Spine

Question 1

• What is the finding and what condition is this associated with?
• What level is most common?
• symptoms?
• treatment?

Answer 1

Facet Cyst (juxtalumbar facet cyst)
- L4-5 most common level (63%)
- Causes lateral recess stenosis, symptoms to the traversing nerve root.
- Highly associated with degenerative spondylolisthesis (82%).
- Presentation is indistinguishable from that of a herniated disk
- MRI: high signal intensity on T2-weighted image sequencing. It appears to be contiguous with the hypertrophied right facet joint, which appears to also have high signal intensity.
- Is it unstable radiographically? pre-operative flexion-extension films to evaluate for instability to include a potential fusion.
○ Yes:** laminectomy, cyst excision w/ instrumented fusion**
* Presence of instability potentiates recurrence of cyst
* Lower rate of recurrent back pain compared w/ laminectomy alone.

Question 2

patients with rheumatoid arthritis and neurologic deterioration in C1-2

What is the most important preoperative imaging finding that predicts full neurologic recovery with surgical stabilization?

Answer 2

PADI>14mm
Boden and associates’ article presents compelling evidence that patients with rheumatoid arthritis and neurologic deterioration in C1-2 instability are more likely to achieve some improvement if the posterior atlanto-dens interval is greater than 10 mm on preoperative studies. All the patients in their series who had neurologic deterioration and a preoperative posterior atlanto-dens interval of greater than 14 mm achieved complete motor recovery.

Boden et al. “The most important predictor of the potential for neurological recovery after the operation was the preoperative posterior atlanto-odontoid interval (PADI). In patients who had paralysis due to atlanto-axial subluxation, no recovery occurred if the PADI was less than 10mm, whereas recovery of at least one neurological class always occurred when the PADI was at least 10mm. All patients who had paralysis and a PADI or diameter of the subaxial canal of 14mm had complete motor recovery after the operation.” They found no correlation with the anterior atlanto-odontoid interval (ADI) with the severity of paralysis or the potential for recovery.

Question 3

Rheumatodid Cervical Spondylitis

Elective patient surgery in patient with RA gets?

Answer 3

Flex-ex films prior to elective surgery.

Question 4

Rheumatoid Cervical Spondylitis

What are the 3 specific patterns of C spine instability in RA patients?

Answer 4

○ Atlantoaxial subluxation (AAS) 1st manifestation…then
○ Atlantoaxial invagination…. then
○ Subaxial subluxation
90% of patients w/ RA, when hx of long standing dz and multiple jt involvement

Question 5

Rheumatoid Cervical Spondylitis

RA patient presents w/ occipital heaches, what is the cause and nerve root involved.

Answer 5

Occipital head aches: erosion of C1-2 compresses C2 nerve root, pain at base of skull relieved w/ manual traction

Question 6

Rheumatoid Cervical Spondylitis

MRI of c-spine in RA, what is the significance of the CMA?

Answer 6

A cervicomedullary angle <135° is suggestive of impending neurologic deterioration with basilar invagination and is an indication for surgical decompression and stabilization.

- MRI: Cervicomedullary angle (CMA) 
	○ Normal 135-175
	○ In progressive superior migration of the odontoid, CMA decreases due to draping of brainstem over odontoid
	○ Reduced CMA had increased association with respiratory dysfunction and sudden death

Question 7

Rheumatoid Cervical Spondylitis

1. Atlantoaxial Subluxation:
   * what is it?
   * % in RA?
   * Dx/Most common findings on XR?

Answer 7

• 1st stage of spine involvement in RA
  - 50-80% of RA patients
  - Pannus formation at synovial joints b/t dens and ring of C1 resulting in destruction of transverse ligament, dens, or both
  - Leads to instability b/t C1 and C2
  - Dx: anterior subluxation of C1 on C2 most common finding.

Xrays to determine AADI and PADI:
- 3.5 mm on flex/ex
- PADI <14 mm more sensitive than AADI measurement for spinal cord compression in patients w/ RA. More sensitive for identifying patients at risk of neuro injury.
Surgery:
- - C1 lateral mass-C2 pedicle/pars fixation (Harms construct) using polyaxial screws
□ Lower rates of vert and C2 n. injury
□ Strongest biomechanical construct
Does not require C1-2 reduction

Question 8

Rheumatoid Cervical Spondylitis: AAS

Xrays determine instability, what radiology parameters do I need to look at? Which one is more sensitive?

Answer 8

Xrays determine mechanical instability: c1-c2 relationship.
* AADI >9-10 mm= surgery due to risk of neurologic injury
* PADI <14 mm= surgery due to risk of neurologic injury
* 3.5 mm on flexion/ext views, though radiographic instability is common in RA and not necessarily indication for surgery.
PADI <14 mm more sensitive than AADI measurement for spinal cord compression in patients w/ RA. More sensitive for identifying patients at risk of neuro injury.

AAOS: patients with rheumatoid arthritis and neurologic deterioration in C1-2 instability are more likely to achieve some improvement if the posterior atlanto-dens interval is greater than 10 mm on preoperative studies. All the patients in their series who had neurologic deterioration and a preoperative posterior atlanto-dens interval of greater than 14 mm achieved complete motor recovery.

Question 9

Rheumatoid Cervical Spondylitis

What is the surgical management for an RA patient w/ neurologic symptoms and imaging findings?

Answer 9

C1 lateral mass-C2 pedicle/pars fixation (Harms construct) using polyaxial screws
* Lower rates of vert and C2 n. injury
* strongest biomechanical construct
* Does not require C1-2 reduction

**C1-2 transarticular screw fixation (Magerl): less commonly used, requires C1-2 reduction, risk of vert artery and C2 nerve injury. **
Odontoidectomy: secondary procedure, anterior cord compression by pannus *often resolves after posterior spinal fusion. *

Question 10

Rheumatoid Cervical Spondylitis

What is the 2nd most common manifestation of RA c- spine? What causes it?

Answer 10

Alantoaxial Invagination (AAI)
superior migration of odontoid, cranial settling, basilar invagination, cranial invagination
* 2nd most common c spine RA manifestation
* 40% of patients
* Tip of dens migrates above foramen magnum
Cranial migration of dens from erosion and bone loss b/t occiput and C1-2

Question 11

Rheumatoid Cervical Spondylitis

Atlantoaxial Invagination:
* Most reproducible xray measure?
* Surgical Indications?

Answer 11

Alantoaxial Invagination (AAI)
* Cranial migration of dens from erosion and bone loss b/t occiput and C1-2
* Ranawat Line: most reproducible:
* - Surgical indications:
- Progressive cranial migration or neuro compromise O-C2 fusion
CMA <135 on MRI = impending neuro impairment

• Occipitocervical fusion: O-C2
  Transoral or retropharyngeal odontoid resection for persistent brainstem compression after O-C2 fusion

Question 12

Rheumatoid Cervical Spondylitis

What does the CMA indicate in Atlantoaxial Invagination?

Answer 12

Alantoaxial Invagination (AAI)
A cervicomedullary angle <135° is suggestive of impending neurologic deterioration with basilar invagination and is an indication for surgical decompression and stabilization

Question 13

Rheumatoid Cervical Spondylitis

Subaxial Subluxation SAS:
Path?
What indicates cord compression?
Surgical indications?
What surgery?

Answer 13

Path: pannus in uncovertebral and facet joints resulting in soft tissue instability of facet&luscka joints.
** SAS > 4 mm or >20% of body is indicative of cord compression**
- Cervical height index (cervical body height/width) less than 2.00 approaches 100% sensitivity and specificity in predicting neurologic compromise.

Surgical indications: pain, progressive compromise, myelopathy, instability, subluxation >4 mm
> 4mm / >20% subaxial subluxation + intractable pain and neurologic symptoms > 4mm / >20% subaxial subluxation + intractable pain and neurologic symptoms

Posterior spinal fusion +/- decompression
- Fusion to most distal unstable level
- Occiput and or C1-2 jt included if AAI or AAS exists

Surgery may not reverse significant neurological deterioration, especially if tight spinal canal is present but can stabilize it.
Anterior Spinal Fusion
* Restore sagittal aligment, may increase likelihood of fusion on multilevel PSF

Question 14

Cervical Myelopathy

MRI: What MRI findings will you see? What correlates to poorer prognosis?

Answer 14

• Effacement of CSF; spinal cord changes (myelomalacia=bright signal on T2; signal changes on T1 correlate w/ poorer prognosis following decompression)
• compression ratio of < 0.4 carries poor prognosis
  CR = smallest AP diameter of cord / largest transverse diameter of cord

Question 15

Cervical Myelopathy: optimal tx depends on individual and the following key considerations (4)

Answer 15

• # of stenotic levels
• Sag alignment of spine
• Degree of motion and desire to obtain
• Medical comorbidities

Question 16

Cervical Myelopathy: combined Anterior and posterior indications

Answer 16

Combined anterior & posterior surgery:
* Multilevel stenosis in rigid kyphotic spine
* Multi-level anterior cervical corpectomies
* Post-laminectomy and kyphosis

Question 17

Cervical Myelopathy Surgery: Laminectomy w/ posterior fusion indications and contra indications?

Answer 17

Indication: Multilevel compression w/ kyphosis <10 degrees. In flexible kyphotic spine, posterior decompression and fusion may be indicated if kyphosis corrected prior to instrumentation.

Contraindication: fixed kyphosis >10 degrees. Will not adequately decompress spinal cord as it is bowstringing anteriorly.

Question 18

Cervical Myelopathy: Laminoplasty indications, contra-indications, technique

Answer 18

• multilevel cervical stenosis that preserves cervical motion. Indications include preserved cervical lordosis and lack of axial neck pain, which suggests fusion would better address arthritic facets and discs
  
  • Maintains motion; avoids complications of in hi-risk pseudarthrosis; congenital cervical stenosis
  • Contraindications: cervical kyphosis >13 degrees contra to posterior decompression; severe axial neck pain pts should be fused.
  • Allows direct posterior decompression of neural elements and indirect anterior decompression allowing the cord to drift posteriorly. Need lordosis to allow for posterior drift of cord otherwise is will bowstring
  • Technique: vol of conal expanded by hinged door laminoplasty followed by fusion
    ○ Open door: hinge created unilateral at junction of lateral mass/lanima and opening on opposite; held open by bone, suture anchors, or plates
    French door: hinge B, opening at midline

Question 19

Cervical Myelopathy: problem with laminectomy alone:

Answer 19

Rare due to risk of post-laminectomy kyphosis. 11-47% risk if laminectomy performed w/o fusion

Question 20

Post-Op cervical myelopathy complications?

Answer 20

Complications:
- Infection: poster>anterior
- Psuedoarthrosis: 12% single level, 30% multilevel
- Post-op C5 palsy: 5%; good prognosis for function recovery, takes time.
○ Deltoid/supraspinatus abduction weakness, flexion weakness, biceps/brachialis
○ Prolonged recovery with motor grade <2
- Recurrent laryngeal nerve injury: RLN vs Left LN debate= nodifference in injury rate. Prolonged retractor placement.
- Dysphagia & alteration in speech: local steroid in retropharyngeal space prior to wound closure decreases rate of dysphagia.
Epidural hematoma: rare, emergent MRI and hematoma evacuation, MRI appearance depends on age, hyperacute <24 hrs hyperintense t2, hypoT1

Question 21

Cervical Myelopathy Alogrithm: 1or 2 levels, < 10 kyphosis

Answer 21

Question 22

Cervical Myelopathy Alogrithm: 1or 2 levels, < 10 lordotic

Answer 22

Question 23

Cervical Myelopathy Alogrithm: 3+ levels, < 10 kyphosis

Answer 23

Question 25

An inverted radial reflex is associated with...

Answer 25

* hypoactive brachioradialis reflex in combination with involuntary finger flexion. * It is a spinal cord “release” sign and is associated with upper motor neuron pathology as seen in cervical stenosis with myelopathy. * ** Radiculopathy is characterized by a diminished reflex but no finger flexion.** Peripheral neuropathy is not associated with any reflex change. ## Footnote aaos

Question 26

What is the most common physical finding in myelopathic patients

Answer 26

The Hoffman sign is the most common finding, occurring in 80% of myelopathic patients, and it is more common with increasing severity of the myelopathy. The prevalence of hyperreflexia has been shown to be no different from the prevalence in individuals without myelopathy. Sustained clonus and Babinski signs have been shown to occur in only one third of the patients with myelopathy. ## Footnote aaos

Question 27

Risk factors for airway complications with ACDF? What were not risk factors?

Answer 27

OR time >5hrs & exposure of 4+ vert bodies involving c4 or higher. Not RF: pulmonary status, smoking, absence of drainage, myelopathy ## Footnote aaos

Question 28

patient has a cervical myelopathy with more than mm of space available for the cord; therefore, she has a reasonable chance of improved neurologic function following surgery

Answer 28

patient has a cervical myelopathy with more than 10 mm of space available for the cord; therefore, she has a reasonable chance of improved neurologic function following surgery. If not treated with surgery, however, her neurologic condition likely will worsen and she will die earlier than if she had surgery. ## Footnote aaos

Question 29

contraindication for posterior decompression (with or without fusion) for myelopathy?

Answer 29

Fixed kyphosis of more than 10 degrees ## Footnote Although cervical instability is a contraindication to posterior decompression alone, segmental instability in the myelopathic cervical spine can be addressed with concomitant posterior fusion with instrumentation. Cervical lordosis represents the ideal scenario for posterior decompressive procedures for myelopathy (laminectomy and laminoplasty) because compression from anterior osteophytes, if present, is relieved as the spinal cord migrates posteriorly. The anteroposterior diameter of the spinal canal does not have an impact on the selection of surgical approach. Posterior unroofing-type procedures in kyphotic cervical spines, however, are ineffective because anterior impingement on the spinal cord will remain; therefore, kyphosis of more than 10 degrees is considered a contraindication for posterior decompression.

Question 30

MRI scan of a 48-year-old man who reports increasing unsteadiness in his gait and hand clumsiness. Examination reveals a positive Hoffmann's reflex bilaterally, positive clonus, and a spastic gait. Xray shows no kyphosis. Management should consist of

Answer 30

The patient has a congenitally small spinal canal with secondary multilevel degenerative changes causing stenosis and cord compression across multiple segments, including directly posterior to the vertebral bodies. A multilevel diskectomy may address the cord compression at the disk level, but not posterior to the bodies, and most likely would be inadequate. The patient has significant stenosis distal to C5, necessitating a more extensive surgical approach than simply C3-C5. Because the patient's cervical lordosis is preserved, a posterior procedure such as laminoplasty or laminectomy would allow the cord to fall away from the anterior pathology and afford decompression. Cervical myelopathy does not tend to resolve, and there is a significant risk for progression; therefore, surgical management usually is recommended.

Question 31

Pt has a hx of ACDF and needs revision, what do you need to consider?

Answer 31

When attempting a revision anterior cervical approach from the side opposite the original approach, it is important to evaluate the function of the vocal cords. If this evaluation reveals dysfunction of the vocal cord on the side of the original approach, then an approach on the contralateral side should not be attempted. Injury to the stellate ganglion, which causes a Horner's syndrome, should not preclude an approach on the contralateral side. While the side of the symptomatology can influence the surgeon's choice as to the side of an anterior approach, it does not preclude a certain approach. When approaching the lower cervical spine from the right side, the recurrent laryngeal nerve can cross the surgical field and should be preserved. Excessive intraoperative pressure on the esophagus can increase the incidence of dysphagia, but its incidence is no different with either approach.

Question 32

Klippel-Feil syndrome

Answer 32

failure of segmentation of the cervical spine. The classic triad includes congenital fusion, low hairline, and a web neck.

Question 33

56 y/o M w/ 2 yr hx of progressive cervical myelopathy and the MRI shown here. What is the most appropriate treatment? Why won't other tx options work?

Answer 33

The cervical spine MRI scan shows spinal stenosis with multilevel spondylosis causing spinal cord compression at multiple levels. With the longstanding duration of the patient's signs and symptoms, combined with involvement of multiple levels in the cervical spine, posterior multilevel laminectomy and fusion is the best treatment option. Two-level anterior diskectomy and fusion would address the two areas of most severe narrowing, but it would fail to decompress the other stenotic areas which also require decompression. Posterior cervical foraminotomies would only address radicular symptoms, which are not present in this patient, and would not succeed in decompression of the spinal cord. Cervical epidural injections are not indicated for myelopathy symptoms, and may in fact place this patient at risk for neurologic deterioration.

Question 34

Cervical Myelopathy surgical outcomes.

Answer 34

* surgery should be performed as soon as possible when cervical spondylotic myelopathy has been diagnosed * Surgical outcome is related to the patient's age, disease course, the presence of osseous spinal stenosis, preoperative comorbidities, the preoperative spinal cord functional score, and the presence of high-signal abnormalities on T2-weighted images. * Patients with focal high-intensity intramedullary signal changes on T2-weighted images have better clinical outcomes following surgery than do patients with demonstrable multisegmental high-intensity intramedullary signal changes on T2-weighted sequences.

Question 35

Nurick Grades in cervical myelopathy and when best to operate?

Answer 35

** 1. signs of cord involvement, but gait remains normal. 2. there are mild gait abnormalities, not affecting the patient's employment status. ** 3. gait abnormalities prevent employment, but the patient remains able to ambulate without assistance. 4. the patient is only able to ambulate with assistance. 5. the patient is chair-bound or bedridden. Clearly, it is desirable to operate when the patient is functioning with a Nurick grade of I or II.

Question 36

What is a contraindication to laminoplasty in a patient with cervical spondylotic myelopathy?

Answer 36

**fixed cervical kyphosis** Laminoplasty or any posterior decompressive procedure is contraindicated in patients with cervical spondylotic myelopathy and cervical kyphosis. The residual kyphotic posture of the cervical spine results in persistent spinal cord compression. The other choices are not contraindications for laminoplasty. Concomitant cervical radiculopathy can be addressed at the time of laminoplasty with a keyhole foraminotomy.

Question 37

Factors associated w/ Psuedoarthrosis rates after ACDF?

Answer 37

**Smoking and DM** * no difference in fusion rates for allograft vs autograft * uninstrumented single level acdf higher rates of fusion than instrumented * level of fusion does not correlate w/ fusion rates

Question 38

Nonsurgical vs Surgical mgmt of LDH

Answer 38

Nonsurgical management is helpful for alleviating symptoms as the herniated disk resorbs. In patients in whom nonsurgical treatment fails to improve symptoms or patients with a neurologic deficit, microdiskectomy is highly effective and is associated with better short- and long-term outcomes than nonsurgical management

Question 39

??% of patients with LDH and radiculopathy experiencing spontaneous resolution of symptoms within 3 months of symptom onset

Answer 39

90% of patients with LDH and radiculopathy experiencing spontaneous resolution of symptoms within 3 months of symptom onset

Question 40

LDH non surgical mgmt:

Answer 40

Acute, less than 6 weeks 1st Line: PT and NSAIDs avoid opioids, +/- oral steroids if NSAIDs ineffective. No support for gabapentin Lumbar ESI: transforaminal or intralaminar approach for short term releief does not change longer term risk for surgery.

Question 41

LDH surgery: limited vs complete diskectomy? Open microdiskectomy vs tubular? Percutaneous endoscopic microdisk? Post op Restrictions?

Answer 41

limited vs complete diskectomy: limited microdiskectomy (only herniated and free fragmented excised) is standard of care. More back pain w/ complete Open microdiskectomy vs tubular? similiar results Percutaneous endoscopic microdisk? no rigorous evaluation, indications unclear Restrictions: equivalent clinical outcomes, irrespective of the length of postoperative restrictions. Do not reduce reherniations and result in slower return to regular activity.

Question 42

LDH outcomes: advantage of surgical mgmt? revision surgery? cauda equina, time frame for surgery?

Answer 42

* Surgery results in faster and more complete improvement, advantage of surgery decreased with time. * Symptom duration >6-9 months may improve less w/ surgery. * Revision surgery: improve, but less improvement compared to primary, higher complication rate * Cauda equina: surgery less than 48hrs better neuro outcomes, pts have improvement in bowel, bladder and sex post op but 25-50% have residual deficit.

Question 43

Trendelenbur gait results from? What level of nerve root would you see?

Answer 43

**A Trendelenburg gait results from weakness of the gluteus medius, L5 nerve root.** A paracentral disk herniation at L4-L5 most commonly results in an L5 radiculopathy and thus weakness of the gluteus medius. A paracentral herniation at L5-S1 most commonly affects the S1 nerve root. A paracentral herniation at L3-L4, a central herniation at L3-L4, and a far lateral herniation at L4-L5 all affect the L4 root.

Question 44

Role of Lumbar ESI? How does ESI compare to microdisk? Who gets the most relief from ESI?

Answer 44

* LDH that fails to repsond for 6 weeks of non-op tx. * 42-56% relief w/ ESI vs 92-98% relief w/ diskectomy. Smaller percentage of relief in the ESI group but those who get relief have similiar duration compared with surgery roughly 3 years * extruded or sequestered herniations report the greatest and most rapid relief. Similarly, those with well-hydrated disk fragments report rapid relief of symptoms.

Question 45

Pt has recurrent radicular symptoms after diskectomy, what imaging needs to be ordered and what's the ddx

Answer 45

MRI with gadolinium will best identify recurrent herniated nucleus pulposus or other root compression and distinguish scar from recurrent disk.

Question 46

Pt factors associated w/ recurrent radicular pain following lumbar diskectomy for sciatica? What are 2 factors associated w/ good outcomes?

Answer 46

Poor: large annular defect at the site of a lumbar disk herniation is associated with persistent radicular pain postoperatively. Good: * Large sequestered herniations * a positive SLR preoperatively correlate with good outcomes after diskectomy.

Question 47

Gaenslen's test

Answer 47

Gaenslen's test is designed to detect sacroiliac inflammation as a source of low back pain.

Question 48

Beevor's sign tests

Answer 48

Beevor's sign tests the innervation of the rectus abdominus and paraspinal musculature (L1 innervation).

Question 49

Lumbar stenosis symptoms? relieving factors?

Answer 49

Lumbar spine stenosis is a disease of exertion, with **exacerbation of symptoms with prolonged standing and walking.** **Relieving factors include lying down, sitting, and lumbar flexion (shopping cart sign).** Patients usually present with neurogenic claudication but also may report radicular complaints or a combination.

Question 50

MRI of lumbar stenosis: what do look at? what is a positive sign?

Answer 50

* Look at sentral canal, lateral recess and intervertebral forament. * Positive sign: Lack of lumbar nerve root sedimentation to dorsal the sac while performing MRI. ## Footnote Axial T2-weighted MRIs of a lumbar spine at a level with no stenosis (A), a level with lateral recess stenosis (B), and a level with central canal stenosis (C). Note the trefoil shape of the canal in panel B, which is not present in panel A.

Question 51

Lumbar stenosis w/ lumbar radiculopathy 2/2 synovial cyst from facet joint, outcome of surgery?

Answer 51

91% reported good pain relief and 82% had improvement of their motor deficits. Epstein reported a 58% to 63% incidence of good/excellent results and a 38 to 42 point improvement on the SF-36 Physical Function Scale. It was also suggested that since the presence of a synovial cyst indicates facet pathology, possible fusion should be considered in these patients, especially those with underlying spondylolisthesis.

Question 52

vascular claudication symptoms then work up

Answer 52

Vascular claudication is a manifestation of peripheral vascular disease and presents with crampy leg pain that is exacerbated by physical exertion. The pain is easily relieved by standing still or sitting. Unlike pseudoclaudication, a forward-flexed posture and/or sitting does not improve the symptoms. Night pain is common in vascular claudication due to the elevation of the extremities and patients often report pain improvement by hanging their extremities in a dependent position. In evaluation of a patient with suspected vascular claudication, the five “P’s” of vascular insufficiency should be monitored, including pulselessness, paralysis, paresthesia, pallor, and pain. While pain and paresthesias can be common in both vascular claudication and pseudoclaudication, the presence of any of the remaining symptoms is suggestive of vascular disease. Next step? **ABI**

Question 53

Indication for spinal fusion in patients undergoing laminectomy for spinal stenosis?

Answer 53

* degenerative spndylolithesis and scoliosis * if spine is destabilized: removal of 1 complete facet joit or iatrogenic pars fx * fusion if very long laminectomy, though 2 level lami itself does not need fusion

Question 54

On an axial CT image, which of the following dimensions is considered to be indicative of a critical amount of lumbar spinal stenosis?

Answer 54

* AP canal diameter less than 10 mm * Cross-sectional area of less than 100 mm2

Question 55

What permanent anatomic pelvic parameter should be measured and considered when determining the amount of lumbar lordosis correction that will be necessary to obtain sagittal balance?

Answer 55

Pelvic incidence ## Footnote Pelvic incidence (PI) is the anatomic angle between the sacral end plate and a line connecting the center of the femoral heads. Increased pelvic incidence has been found to correlate with the incidence and severity of spondylolisthesis. Patients with increased PI require increased lumbar lordosis to restore sagittal balance. Pelvic tilt (PT) and sacral slope (SS) have also been found to correlate with lumbar lordosis; however, both PT and SS can change depending on pelvic rotation. PI is the only permanent pelvic parameter that is unaffected by pelvic rotation. Acetabular and femoral version have not been found to be associated with lumbar lordosis.

Question 56

Pelvic Incidence, increased PI associated with?

Answer 56

* angle between sacral end plate and line connecting center of femoral heads. * Increased pelvic incidence has been found to correlate with the incidence and severity of spondylolisthesis * Patients with increased PI require increased lumbar lordosis to restore sagittal balance. Pelvic tilt (PT) and sacral slope (SS) have also been found to correlate with lumbar lordosis; however, both PT and SS can change depending on pelvic rotation. PI is the only permanent pelvic parameter that is unaffected by pelvic rotation. Acetabular and femoral version have not been found to be associated with lumbar lordosis.

Question 57

Isthmic spondylolisthesis results from a defect in the

Answer 57

pars interarticularis (spondylolysis). ## Footnote **Spondylolysis** can occur independently or in association with spondylolisthesis and often occurs at the L5-S1 level. **Spondylolisthesis** is the forward displacement of one vertebra with respect to the adjacent caudal vertebra.** Spondyloptosis** is defined as 100% translation of one vertebra over the next caudal vertebra

Question 58

Isthmic spondylolisthesis is the most common type of spondylolisthesis in children and young adults. It occurs in % of the population.

Answer 58

Isthmic spondylolisthesis is the most common type of spondylolisthesis in children and young adults. **It occurs in 5% of the population.**

Question 59

A 40-year-old man has intractable pain following 2 years of nonsurgical management for high-grade spondylolisthesis. What is the best surgical option?

Answer 59

Circumferential fusion is the preferred choice for patients undergoing revision surgery following failed posterolateral fusions for isthmic spondylolisthesis as well as for those patients having primary surgery for high-grade isthmic spondylolisthesis.

Question 60

An adult patient with a grade I isthmic spondylolisthesis at L5-S1 is most likely to have weakness of the

Answer 60

EHL Adult patients with isthmic spondylolisthesis most commonly have neurologic symptoms due to foraminal stenosis at the level of the spondylolisthesis. In this scenario, the patient is most likely to have weakness of the L5 myotome, which would cause weakness of the extensor hallucis longus.

Question 61

What nerve root is prone to injury after reduction of spondylolisthesis? Eg reduction of grade II l5-S1 spondy

Answer 61

L5 nerve root is especially vulnerable and prone to injury after the reduction of spondylolisthesis in patients with mid-and high-grade isthmic spondylolisthesis

Question 62

Spondylolisthesis is best classified as?

Answer 62

Spondylolisthesis can be classified into five types. Type I, dysplastic, occurs at the lumbosacral junction as a result of congenital abnormalities of the upper sacrum and/or the arch of L5. Type II, isthmic, refers to those involving a lesion in the pars interarticularis. Type IIA, lytic, represents fatigue fractures of the pars. Type IIB describes those with elongated, but intact pars. Type IIC describes those that are a result of an acute fracture of the pars. Type III, degenerative spondylolisthesis, results from long-standing intersegmental disease. Type IV, traumatic, refers to those resulting from fractures in regions other than the pars, such as the pedicles. Type V, pathologic, refers to spondylolisthesis resulting from generalized or local bone disease

Question 63

Most common complication of surgical mgmt of degen spondylolisthesis.

Answer 63

A dural tear is one of the most common complications encountered during the surgical management of degenerative spondylolisthesis. The incidence of incidental durotomy in the literature ranges from **4% to 9%**. **Close in water tight fashion. ** **Durotomy has no negative long-term effects on patient oucomes.**

Question 64

rate of revision surgery in same segment disease for degen spondylolisthesis higher for??

Answer 64

The rate of revision surgery in the management of same-segment disease was found to be much higher in patients with degenerative spondylolisthesis who underwent laminectomy alone compared with patients who underwent laminectomy and instrumented fusion

Question 65

Risk factors for adjacent-segment disease include

Answer 65

Risk factors for adjacent-segment disease include higher body mass index, preoperative degenerative changes of the disk space and the facet joints, and sagittal imbalance.34 In addition, longer constructs lead to an increased incidence of adjacent-segment disease and, therefore, increased long-term revision surgery rates.35

Question 66

best radiographic indicator of segmental instability at L4-L5

Answer 66

More than 4 mm of translation or 10 degrees of angulation compared with adjacent levels on flexion/extension radiographs. Motion segments that demonstrate more than 4 mm of translation or 10 degrees of angulation compared with adjacent motion segments on flexion-extension radiographs have excessive motion and instability

Question 67

If a laminectomy for spinal stenosis is performed, which of the following is an indication for concomitant arthrodesis at that level?

Answer 67

**Degenerative spondylolisthesis at the level of the laminectomy** A prospective randomized study of patients with degenerative spondylolisthesis and spinal stenosis by Herkowitz and Kurz showed significantly improved clinical outcomes in patients who also received a lumbar arthrodesis. Patients with a laminectomy at an adjacent level do not have improved outcomes with an arthrodesis. Minimal lumbar scoliosis does not require arthrodesis. Arthrodesis is indicated in cases where there is removal of more than 50% of the facets bilaterally but not with an associated foraminal stenosis.

Question 68

Most common finding from medial breach of pedicle screw?

Answer 68

most common finding at exploration of an inappropriately placed pedicle screw is** displacement of the nerve**. Pedicle breach is common, ranging from 2% to 20%, but most are asymptomatic. ## Footnote large series conducted by Lonstein and associates, the authors reported that displacement of the root, most often medial, was the most common finding. Laceration, contusion, or transfixion usually was not seen. Spinal fluid leakage occurs less frequently and is not expected in the minimal broach illustrated.

Question 69

What factor is associated with the highest risk for in-hospital complications for patients undergoing a lumbar fusion for degenerative spondylolisthesis?

Answer 69

**Age and having three or more comorbidities is associated with a higher rate of complications in patients undergoing a lumbar fusion for lumbar degenerative spondylolisthesis.** Race, gender, and hospital size have not been found to be associated with higher complication rates.

Question 70

# Thoracic Stenosis: Thoracic stenosis: what are the 2 conditions, how do they differ? indication for surgery? Surgical management: posterior vs ventral?

Answer 70

Two distinct clinical syndromes of thoracic stenosis 1. most common degenerative changes of the spine. 2. Thoracic spinal cord stenosis secondary to congenital narrowing of the spinal canal is associated with a more abrupt onset of symptoms. The typical clinical manifestations of myelopathy may commence following minor or moderate trauma. * Indications for surgery include progressive thoracic myelopathy and persistent unremitting radicular pain. **Laminectomy** * indication for thoracic laminectomy is a patient in whom imaging has demonstrated evidence of **spinal canal stenosis secondary to hypertrophy of the posterior elements**. * Posterior laminectomy alone is contra-indicated because of inability to retract spinal cord and high rate of associated nuerologic injury. Should not be the primary approach when stenosis results from a significant ventral epidural osteophyte or herniated disk * **Anterior transthoracic** approaches allow direct access to herniation but require going into the chest. Discetomy and hemicorpectomy performed as needed *** Posterior transpedicular, costotransversectomy, or posterolateral extracavitary** approaches may allow for access to the disc herniation while avoiding the need to enter into the chest cavity; however, they require stabilization and fusion to reduce the risk of late spinal instability.

Question 71

Most common place for thoracic disc herniations

Answer 71

Most thoracic disk herniations occur in the lower (caudal) third of the thoracic spine. This predilection may be related to the unique anatomic and biomechanical environment of that region. The 11th and 12th ribs do not join the rib cage anteriorly and do not form a true articulation with the transverse processes posteriorly. Furthermore, flexion and torsional forces tend to concentrate between T10 and L1.

Question 72

# Thoracic disc herniations Symptomatic herniations of the thoracic spine are --- than those of the cervical or lumbar region. They tend to occur most commonly during the ---- decades of life and although they can be found at all levels, they are most common in the -----. ------ has the highest rate of neurologic deterioration and is not recommended. Multiple studies have shown that herniated thoracic disks can be found at one or more levels in ---% of asymptomatic individuals.

Answer 72

1. Less common than those in C & L spine 2. 3rd-5th decades of life 3. more than two thirds are found at T9-T12, which is the more mobile lower third of the thoracic region. 4. Posterior Laminectomy and disc excsion high rate of neurologic deterioration, posterior approaches cause manipulation of the spinal cord which should be minimized 5. 40% asymptomatic ## Footnote Symptomatic herniations of the thoracic spine are much less common than those of the cervical or lumbar region. They tend to occur most commonly during the third to fifth decades of life and although they can be found at all levels, they are most common in the lower third near the thoracolumbar region. Posterior laminectomy and disk excision has the highest rate of neurologic deterioration and is not recommended. Multiple studies have shown that herniated thoracic disks can be found at one or more levels in 40% of asymptomatic individuals.

Question 73

Thoracic disk herniation radicular symptoms

Answer 73

pattern of radiating pain has been described as either following the dermatomal band around the chest or feeling to the patient as if the pain passes straight anteriorly to the chest wall.

Question 74

Concern for calcified disk herniations

Answer 74

Occur more commonly in thoracic spine More symptomatic Risk of dura tear as it adheres to the dura Higher risks of complication if managed surgically

Question 75

Axial-based pain may be disk-based or facet-based and is transmitted through the ?, which innervates the facets, and the 2?, which innervates the posterior anulus.

Answer 75

medial branch of the dorsal root ganglia sinuvertebral nerve

Question 76

What region of the spine is most susceptible to changes in the vascular supply to the spinal cord during an anterior approach?

Answer 76

T8-T12 artery of Adamkiewicz, also known as the great anterior medullary artery, most typically arises off the left side of the aorta between T8 and T12. It represents the sole medullary blood supply to the thoracic spine

Question 77

Conus medullaris syndrome:

Answer 77

most commonly accompanies injuries at the T12-L2 region. Conus medullaris syndrome most frequently occurs as a result of trauma or with a disk herniation at L1, resulting in a lower motor neuron syndrome but with a poor prognosis for recovery of bowel and bladder dysfunction. The conus region, as the termination of the spinal cord, contains the motor cell bodies of the sacral roots. The syndrome is usually a sacral level neural injury; therefore, lower extremity weakness is uncommon.

Question 78

The anulus of the disk is a fibrous layer consisting of obliquely oriented type ? collagen molecules. The softer nucleus is a remnant of the embryologic notochord and is composed of type ? collagen molecules.

Answer 78

anulus type I nucleus type II

Question 79

3 most common causes of LBP

Answer 79

three most common causes of axial LBP in adults are the intervertebral disk (40%), the lumbar facet joint (15% to 30%), and the sacroiliac joint (20%).

Question 80

what is bertolotti syndrome

Answer 80

In some patients, a partially sacralized L5 vertebrae may form a pseudoarticulation with the sacrum (Bertolotti syndrome) and may be the source of LBP.9 The prevalence of such a finding is approximately 5%.

Question 81

Desribe the pathology of DDD: proteoglycan concentration? Water content? Pyridinoline crosslinks? Pentosidine crosslinks (marker for)? Decorin and Biglycan?

Answer 81

In patients with DDD, the disk undergoes a series of changes that leads to alteration of the local biology and architecture. DDD is characterized by a decline in proteoglycan concentration with loss of water content, reduced viable cells, a decrease in pyridinoline crosslinks, and an increase in pentosidine crosslinks. Pentosidine is a marker of advanced glycosylation. Decorin and biglycan are observed in relatively increased concentrations as the disk degenerates. Decreased disk height results in altered spinal biomechanics, furthering the degenerative cascade of the spinal segment.

Question 82

RFN for LBP, what is it and what does it block

Answer 82

RFN is performed under biplanar fluoroscopic guidance. The goal of RFN is thermal coagulation of the nociceptor, the medial branches of the primary dorsal rami innervating the facet joint

Question 83

adjacent segment disease lumbar spine: biomechanical cause and risk factors

Answer 83

Biomechanically, fusion increases adjacent level intradiscal pressure, facet loading, and hypermobility. Risk factors * pedicle screw fixation, * facet joint violation, * sagittal malalignment, * longer fusion length.

Question 85

# lumbar interbody fusion factors associated with early post operative migration of "stand-alone' lumbar interbody fusion

Answer 85

**Posterior approach, ** Postoperative migration of lumbar interbody fusion cages is a rare complication. It is most commonly seen after placement of the cages through a posterior approach, with instability of the final construct. *It is not associated with the design of the cage, the type of graft used, or a resultant pseudarthrosis.*

Question 86

alignment of againg spine

Answer 86

* lumbar lordosis gradually decreases * sagittal vertical line moves anteriorly relative to the sacrum * Overall kyphosis in the thoracic spine gradually increases, but the coronal balance remains essentially the same unless scoliosis develops. ## Footnote The primary change that takes place in the aging spine is degeneration of the lumbar disks and loss of the overall lumbar lordosis

Question 87

afferent pain innervation of the L3-L4 facet joint arises from the medial branch nerve of

Answer 87

**L2 and L3 medial branch nerves** Afferent pain fibers to the lumbar facet joints arise from the medial branch nerves originating from the next two cephalad levels. Therefore, innervation of the L3-L4 facet joint arises from the L2 and L3 medial branch nerves. This effect should be taken into account when considering a medial branch block or facet denervation. The medial branch nerve arises from the dorsal ramus of the exiting nerve root.

Question 88

Anterior approach to lumbosacral juntion associated with

Answer 88

Retrograde ejaculation: sequela of injury to the superior hypogastric plexus. L5-S1 exposure ## Footnote use of monopolar electrocautery should be avoided in this region. The ideal exposure starts with blunt dissection just to the medial aspect of the left common iliac vein, sweeping the prevertebral tissues toward the patient’s right side. Although erectile dysfunction can be seen after spinal surgery, it is not typically related to the surgical exposure because erectile function is regulated by parasympathetic fibers derived from the second, third, and fourth sacral segments that are deep in the pelvis and are not at risk with the anterior approach. The other choices are complications of spinal surgery but are not uniquely associated with an anterior L5-S1 exposure

Question 89

most common complication following total disk arthroplasty in the lumbar spine?

Answer 89

Transient radicular leg pain without evidence of nerve root compression. ## Footnote In a midterm (7 to 11 years) follow-up study of lumbar total disk arthroplasty, 5 of 55 patients had transient radicular leg pain without evidence of nerve root compression. Implant migration is rare. Deep venous thrombosis, incisional hernia, and retrograde ejaculation are less common complications of disk arthroplasty.

Question 90

risk factors for the development of low back pain?

Answer 90

* poor physical fitness * smoking * a history of repetitive bending or stooping on the job, * whole body vibration exposure ## Footnote Some radiographic factors such as stenosis, spondyloarthropathy, severe deformity, or instability are also associated with low back pain. Gender, weight, transitional anatomy, or facet trophism are not associated with low back pain.

Question 91

Corset-type brace does what?

Answer 91

Decrease intradiskal pressure, no significant alteration to motion

Question 92

Most common cause of hematogenous spinal infection

Answer 92

urinary tract is a common source for hematogenous spinal infection, but the source was found in only 27% of 111 patients

Question 93

Injury to the sympathetic chain during a lumbar retroperitoneal approach

Answer 93

Sympathectomy: ilpsilateral approach to lumbar spine, injuries sympathetic chain on that side resulting in a warm, red foot creating the appeacher that the normal cooler foot may have compromised circulation concerning for limb ischemai. Tx: self limited, no specific treatment

Question 94

Lumbar disk replacement: comparision to fusion? contraindication? adj segment disease?

Answer 94

* pain relief equivalent to fusion * no study demonstrates that normal motion is restored * pre-existing facet arthropathy is a contraindication. * no long term data on reduced incidence of adj segment disease

Question 95

best initial study for discogenic back pain?

Answer 95

Radiography is the best initial study for the evaluation of diskogenic low back pain. The normal degenerative process can be evaluated. Vacuum phenomenon may be found within the disk space. Other possible sources for back pain should also be evaluated. The other tests may be beneficial but represent later imaging options.

Question 96

Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration

Answer 96

* Cognitive intervention and exercise had similiar results for low back pain and disc degeneration. * this was "Modern rehab program" different to usual care of the 90s in a previous study ## Footnote Brox and associates reported on a randomized clinical trial comparing lumbar fusion to cognitive intervention and exercise and found similar results in both groups, with significantly less risk in the latter.

Question 97

Revision options for total disk replacement: time frame/options

Answer 97

w/in 2 weeks, after that posterior fusion w/ or w/o laminectomy ## Footnote Revision anterior exposure within 2 weeks of total disk replacement incurs relatively little additional morbidity because adhesion formation is minimal. Surgeons should have a low threshold for revising implants that are clearly dangerously malpositioned or show early migration within this 2-week window. Beyond this time period, a revision strategy must be individualized to the particular clinical situation. A posterior fusion with instrumentation with or without a laminectomy is currently the most effective salvage procedure.

Question 98

What are modic changes?

Answer 98

Vertebral body marrow changes to the end plate seen on MRI associated with DDD.

Question 99

modic changes: types and MRI findings

Answer 99

Modic type 1: represents bone marrow edema and inflammation T1: low signal; T2: high signal T1 C+ (Gd): enhancement Modic type 2: represents normal red haemopoietic bone marrow conversion into yellow fatty marrow as a result of marrow ischemia T1: high signal T2: iso to high signal Modic type 3: represents subchondral bony sclerosis T1: low signal T2: low signal

Question 100

Retrograde ejaculation is most commonly associated with what surgical approach?

Answer 100

* Anterior transperitoneal approach to L5-S1 * injury to the superior hypogastric plexus * can be injured with anterior or anterolateral spine surgery at any lumbar level, it is most at risk with anterior transperitoneal approaches to the lumbosacral junction ## Footnote Retrograde ejaculation is the sequela of an injury to the superior hypogastric plexus. This structure needs protection, especially during anterior exposure of the lumbosacral junction. Although the superior hypogastric plexus can be injured with anterior or anterolateral spine surgery at any lumbar level, it is most at risk with anterior transperitoneal approaches to the lumbosacral junction. To avoid this complication, the use of monopolar electrocautery should be avoided during deep dissection in this region. The ideal anterior exposure starts with blunt dissection just to the medial aspect of the left common iliac vein sweeping the prevertebral tissues toward the patient's right side.

Question 101

What is this finding, how common is it, what kind of symptoms can happen and why?

Answer 101

**Unilateral sacralization** * L5 Bertolotti syndrome * 12-21% presence in population * The altered biomechanics have been postulated to cause low back pain by placing increased stress on the adjacent cephalad disk, thus contributing to accelerated degenerative disk disease at this level. It has also been found that the neoarticulation between the enlarged transverse process and the sacrum and/or ilium may be a source of neural impingement on the exited L5 nerve root and results in radicular pain syndrome

Question 102

Which lumbar disk components has the highest tensile modulus to resist torsional, axial, and tensile loads?

Answer 102

**annulus fibrosis** * * multilayer lamellar architecture mode of* type I collagen fibers.* * Each successive layer is oriented at 30 degrees to the horizontal in the opposite direction, “criss-cross” type pattern. * This composition allows the annulus, which has the highest tensile modulus, to resist torsional, axial, and tensile loads.

Question 103

What does cochrane review say about intradiskal electrothermal therapy?

Answer 103

The Cochrane Review states that preliminary results of three small trials of intradiskal electrotherapy suggest that it is ineffective

Question 104

Predominant nucleus collagen?

Answer 104

Type II ## Footnote Types I and II collagen are the predominant types of collagen found in the intervertebral disk. Type I collagen is present in the highest concentration in the annulus fibrosus and type II collagen in the nucleus pulposus. Type V collagen is present in small concentration in the annulus fibrosus. Type VI collagen is a non-fibrillar, short-helix collagen found in both the annulus and nucleus. Type XII is present in the annulus fibrosus only.

Question 105

MoM disk replacement ion levels, how do the compare to THA MoM

Answer 105

* The serum ion levels measured are similar in terms of their level to the values measured in total hip arthroplasty metal-on-metal prostheses. * According to two studies looking at patients with a cobalt-chrome metal-on-metal lumbar disk arthroplasty, serum ion levels in these patients were similar to values measured in patients with total hip arthroplasty metal-on-metal prostheses.

Question 106

. Approximately ---- of LBP is from the SI joint. LBP is more common in patients who have undergone lumbosacral fusion. L5-S1 fusion increases stress on the joint by ---% and L4 through S1 fusion increases the stress on the joint by ---%.

Answer 106

Approximately 15% to 30% of LBP is from the SIJ.1-4 LBP is more common in patients who have undergone lumbosacral fusion.5 L5-S1 fusion increases stress on the joint by 50% and L4 through S1 fusion increases the stress on the joint by 168%. | The sacroiliac joint (SIJ) accounts for 15-30% of lower back pain and oc

Question 107

what innervates the SI joint

Answer 107

ventral lumbosacral plexus and the dorsal primary rami of S1 through S4 may potentially innervate the SIJ

Question 108

SI joint physical exam

Answer 108

Question 109

What is the vacuum phenomenon

Answer 109

The vacuum phenomenon suggests gas in the joint space, suggestive of joint mobility, which may also be a result of degenerative changes.

Question 110

Ways to dx SIJ pain

Answer 110

Fortin finger sign 3/5 positive exam signs atleast 50% reduction in image guided SIJ inction.

Question 111

Non op Tx of SI joint pain

Answer 111

* physical therapy, NSAIDs, sacroiliac belts, manual therapy, * Target injections as dx and therapeutic * radiofrequency ablation for those with positive response to injection. may provide longer lasting therapeutic benefit

Question 112

SI joint fusion

Answer 112

The best data to date comes from two randomized controlled trials involving the use of bone ongrowth triangular titanium rods. Both trials showed clinically important improvement in patients who underwent surgical treatment compared with nonsurgical treatment. **clinically meaningful improvement in Oswestry Disability Index and visual analog scales scores** ## Footnote (>6 months of failed nonsurgical management, three of five positive physical examination findings, >50% reduction of pain with image-guided local anesthetic injections, and hip and spine ruled out as pain generators) experienced a 50% reduction of in Oswestry Disability Index and visual analog scale scores.

Question 113

Which of the following ligaments is least involved in stabilizing the sacroiliac joint?

Answer 113

The SI joint is stabilized by the anterior and posterior sacroiliac ligaments, the sacrotuberous ligament, and the sacrospinous ligament. The interosseous ligament is a component of the posterior sacroiliac ligament that connects between the sacrum and ilium. **The iliolumbar ligament joins the L4 and L5 to the iliac crest and strengthens the lumbosacral joint.**

Question 114

Post op SI joint fusion

Answer 114

To improve outcomes, patients are recommended to adhere to safe post-operative strategies, including** heel-toe, touch-down weight bearing with the use of a front-wheeled walker or crutches for 3 weeks.** Weight bearing is progressively increased until patients are fully ambulatory. **Physical therapy is also highly recommended for 1-3 weeks to assist in their rehabilitation.**

Question 116

Degen Spondy More common in which population? Most common level? Risk factors?

Answer 116

* Black, DM, Women >40 * 8x women>men (ligamentous laxity?) * L4/5 5x more common *isthmic spondy at l5/S1 * RF: sacralization of L5 (transitional l5 vert) * sagitally oriented facets

Question 117

Degen Spondy: L4/5 slip will cause what kind of stenosis.

Answer 117

* Central and lateral recess: L5 nerve root compression in lateral recess * Foraminal: L4 nerve root compressed as vertical height is lost and slips forward.

Question 118

Degen Spondy: L4/5 slip will cause what kind of stenosis.

Answer 118

* Central and lateral recess: L5 nerve root compression in lateral recess * Foraminal: L4 nerve root compressed as vertical height is lost and slips forward.

Question 119

L4 nerve findings L5 nerve findings

Answer 119

L4: Quad weakness (sit to stand test), ankle dorsiflexion (crossover w/ L5), decreased patella reflex L5: ankle DF weakness (heel walk exam-L5 crossover) , EHL weakness, glute med weakness (hip abduction)

Question 120

Risk factors for adj segment disease after** posterior lumbar fusion** and overall incidence

Answer 120

Risk factors identified were multi-level surgery (3-4 levels 5x likely), age > 60 years, and an adjacent level laminectomy. Overall, the average incidence of adjacent segment disease requiring surgery was 2.5% per year. 10 year incidence 22.2%

Question 121

What percentage of patients will need additional surgery after fusion for ASD in lumbar spine?

Answer 121

SPORT data18% require additional surgery w/in 8 years New data suggests 20-29% at 10 years

Question 121

Tx of degen spondy: tx for best long term outcomes?

Answer 121

Decompression and fusion do best in long term. Instrumented fusion has increased fusion rates. Solid arthrodesis patients have been results than pseudo arthrosis

Question 122

Degen Spondy: Posterior Decompression and Fusion: Outcomes? What is the benefit of adding a cage? When is ALIF indicated?

Answer 122

- 79% have satisfactory outcomes - improved fusion rates w/ pedicle screws - improved outcomes w/ successful arthrodesis (compared to pseudo) - Worse outcome in smokers - No benefit of adding a cage: increases hospital costs w/o increasing fusion rate, no difference in outcome scores for patients - ALIF for revision cases, risk of retrograde ejacuation. superior hypogastric plexus ## Footnote Usually combined with PLIF or TLIF (IF = interbody fusion) Decompression (laminectomy, wide decompression, foraminotomy)

Question 123

Cortical Screw vs Pedicle Screw

Answer 123

Cortical Screws decrease lateral exposure needed * lower intraoperative blood loss, smaller skin incision, and decreased pain scores at 1-week post-op * similiar fusion rates * starting point is more medial and caudal than traditional pedicle screws, trajectory is more cephalad and lateral than traditional screw

Question 124

**Complications of fusion for posterior decompression and fusion** Psuedoarthrosis: ASD: SSI: Positional neuropathy: Complications rates increase with:

Answer 124

Psuedoarthrosis: 5-30% get CT scan ASD: 2-3 % per year Infection: 0.1-2% I&D retain hardware Positional neuropathy: LFCN from prone w/ iliac bolster Complications rates increase with older age, increased EBL, longer OP times, number of levels fused.

Question 125

Ankylosing Spondylitis: Dx Criteria Orthopedic Manifestions Labs Radiographs tx:

Answer 125

* Bilateral Sacroillitis, +/- Uveitis, HLA B27 (90%) (limitation of chest wall expansion < 2cm of expansion is more specific than HLA-B27 for making diagnosis) * Progressive kyphotic spine deformity, Cervical Fxs, Hip and Shoulder arthritis (hip flexion contracture * Labs: HLA B27+, RF negative, mild ESR/CRP/WBC elevations * Exam: limited chest wall expansion, decreased spine motion, + FABER, hip flexion contracture, kyphotic spine deformity * enthesitis + disc space involvement * disc space involvement, AS in cervical spine will show ossification of disc space, marginal syndesmophytes, squaring of vertebral bodies * tx: NSAIDS, COX-2 inhibitors, and therapy * 2nd line: infliximab, etanercept, adalimumab clinical studies show improvement. ## Footnote Seronegative arthropathy: RF negative

Question 126

THA considerations for AS

Answer 126

pts w/ AS has more vertical and anteverted acetabulums, higher risk of anterior dislocation

Question 127

Pt with AS, head trauma, how do you want to immobilize prior to imaging

Answer 127

Due to the high risk of fracture and spinal instability, the patient should be immobilized in a hard collar in his existing kyphotic position and admitted for additional imaging and observation for progressive neurological deficits, despite his normal neurological exam.

Question 128

Trauma in AS vs DISH

Answer 128

Hi rate of neuro injury in both groups, minor trauma leads to unstable 3 column injury AS higher risk of neurological injury, AS has higher rate of surgical tx, Equivalent mortality rate ## Footnote Patients with AS are also at high risk of developing epidural hematoma after spine trauma compared to those with normal spines due to tethering of epidural vessels. Westerveld et al. performed a systematic review of case series regarding the treatment, neurologic status, and complications of patients with DISH or AS presenting with spine fractures. The authors reported that DISH patients had higher thoracic spine injuries (34.5% compared to 10.7%) with fractures that propagated through the vertebral body, whereas AS patients almost always had cervical spine involvement with fractures occurring through the disc space and initially present with neurologic deficits. They found patients with DISH had higher mortality rates with both surgical and conservative treatment measures, but AS patients had higher complications rates following both surgical and nonsurgical treatment. The authors concluded that patients with an ankylosed spine are prone to worse clinical outcomes compared to those following spinal injuries in the general populatio

Question 129

Pediatric Spondylolysis & Spondylolisthesis: continuum of disease, define Pars Stress rxn -> spondylolysis -> isthmic spondylolithesis -> spondyloptosis

Answer 129

* Pars Stress rxn: sclerosis of pars w/o complete disruption * Spondylolysis: fracture through the pars, not present at birth 4-6% of population and develop overtime, 2/2 hyperextension * isthmic spondylolithesis: lithesis of 2/2 pars defect, **pars defects have 15% risk of progression to isthmic spondylilithesis** * spondyloptosis: complete 100% slip, rare.

Question 130

risk of progresion from pars defect: %, types at risk?, correlation to PI

Answer 130

* Isthmic spondylolithesis of 2/2 pars defect, **pars defects have 15% risk of progression to isthmic spondylilithesis** * larger slips (meyerdig 2 >50% slip) higher risk of progression * dysplastic (wiltse I) likely to progression * severity of slip correlated with PI ## Footnote Risk factors for slip progression include presentation before adolescent growth spurt, female gender, >50% slip on initial diagnosis, dysplastic spondylolisthesis, and increased slip angle.

Question 131

Adolescent with a pain and pars? next steps?

Answer 131

avoiding strenuous activities prevented the formation of pars defects in patients with impending spondylolysis. Early diagnosis was made with MRI. Patients should wear a lumbosacral orthosis full time for 6 to 12 weeks.

Question 132

Degen Spondy: who's a candidate for surgery, what are the results?

Answer 132

AAOS: Patients with a degenerative spondylolisthesis and severe stenosis who have failed appropriate nonsurgical management are candidates for surgical intervention. Most studies show good to excellent results in more than 85% of patients after lumbar decompression for stenosis. Atlas and associates found that at 8- to 10-year follow-up, leg pain relief and back-related functional status were greater in those patients opting for surgical treatment of the stenosis. Similarly, the decision to fuse a spondylolisthetic segment has been supported in the literature. Herkowitz and Kurz compared decompressive laminectomy alone and decompressive laminectomy with intertransverse arthrodesis in 50 patients with single-level spinal stenosis and degenerative spondylolisthesis. They demonstrated good to excellent results in 90% of the fused group compared to 44% in the nonfusion group. The decision to include instrumentation during the fusion is more controversial. Whereas the use of instrumentation has shown to improve fusion rates, it has not been conclusively shown to improve the overall clinical outcomes of patients.

Question 133

What is the most common physical examination finding in a patient with chronic painful spondylolysis?

Answer 133

Patients with spondylolysis typically demonstrate increased pain with lumbar extension, not with forward flexion. In the absence of a disk herniation, a straight leg raise test result should be negative. Pain with forward flexion is not common in spondylolysis, and without nerve root impingement there should be no loss of the tendo-Achilles reflex.

Question 134

How would a chronic spondylosis show up on MRI? What is the tx?

Answer 134

chronic L5 spondylolysis (no increased signal on STIR-weighted MRI). If failed an extensive course of physical therapy, the next best step in management is LSO bracing for 6-12 weeks. ## Footnote Pediatric spondylolysis is one of the most common causes of pediatric and adolescent low back pain. These defects develop over time and are seen in 4-6% of the population. The most common cause is repetitive hyperextension seen in gymnasts, football players, and weightlifters. The incidence of progression to high-grade spondylolisthesis is around 15%. Treatment involves activity modifications and an extensive course of PT. If patients remain symptomatic, rigid LSO bracing in a hypolordotic posture is believed to unload the posterior elements and decrease shear stresses across the pars. Healing of the pars defect does NOT correlate with clinical outcome therefore surgical procedures are reserved only for patients who have failed an extensive course of non-operative measures, have neurological deficits or have very high-grade slips.

Question 135

The sagittal vertical axis

Answer 135

is a plumb line dropped from C7 and should fall behind the hip joints and within 4 to 5 cm of the posterior corner of S1 (an easily identifiable radiographic marker).

Question 136

Pelvic Incidence vs Pelvic Tilt

Answer 136

Pelvic incidence is a constant that is unique to each patient's spinopelvic anatomy. Pelvic incidence typically is within 10 degrees of the lumbar lordosis in an upright adult. Pelvic tilt (PT), on the other hand, can vary based on a patient's stance. PT is an indicator of the amount of compensation a patient has developed by retroverting their pelvis to stand upright. In an upright patient who is not compensating for loss of spinal sagittal alignment, the PT should be less than 20 degrees.

Question 137

SSEP and MEP amplitude percentages that indicate possible intra-operative neurologic complication

Answer 137

Sustained decreased SSEP amplitudes of greater than 50% and transcranial electric Motor-Evoked Potentials (tceMEP) amplitudes of greater than 75% are indicative of a possible significant intraoperative neurologic complication.

Question 138

What is PI? How is it releated with spondy? sagittal balance? PT and SS?

Answer 138

Pelvic incidence (PI) is the anatomic angle between the sacral end plate and a line connecting the center of the femoral heads. Increased pelvic incidence has been found to correlate with the incidence and severity of spondylolisthesis. Patients with increased PI require increased lumbar lordosis to restore sagittal balance. Pelvic tilt (PT) and sacral slope (SS) have also been found to correlate with lumbar lordosis; however, both PT and SS can change depending on pelvic rotation. PI is the only permanent pelvic parameter that is unaffected by pelvic rotation. Acetabular and femoral version have not been found to be associated with lumbar lordosis.

Question 139

# sagital imbalance Osteopenic Pt with long instrumented fusion needs fixation to pelvis vs just sacrum why?

Answer 139

Do decrease risk of sacral fractures, long instrumented fusions to the sacrum impart a high degree of strain, and the sacrum may fail in a transverse fracture or fracture-dislocation pattern.

Question 140

# sagital imbalance Pseudo arthrosis after ASD correction, must common site

Answer 140

Lumboscral junction l5-s1

Question 141

# sagital imbalance When posterior fusion with instrumentation to the sacrum is used to treat adult scoliosis, what instrumentation technique best increases the chance of a successful lumbosacral fusion?

Answer 141

As the chance of success of lumbosacral fusion increases with the stiffness and rigidity of the construct, fixation and stiffness improve with fixation into both the upper sacrum and the ilium. In a review of individuals treated with long constructs to the pelvis for adult scoliosis, Islam and associates reported that the rate of pseudarthrosis was significantly lower with sacral and iliac fixation compared with sacral fixation alone or iliac fixation alone. Iliac screws provide significant fixation anterior to the instantaneous axis of rotation for flexion and extension, as well as provides resistance to lateral bending and rotational forces. Numerous biomechanical studies support the concept of increasing biomechanical stabilization with increased fixation from the sacrum to the ilium.

Question 142

Pt w/ flat back syndrome who get what kind of osteotomy? What levels? whats a contraindication? How many degrees of correction can you get

Answer 142

**Pedicle subtraction osteotomy** is the preferred osteotomy technique for the treatment of many patients with iatrogenic flatback syndrome. In the *presence of an anterior pseudarthrosis,* however, it must be done in conjunction with an anterior procedure. Prior laminectomy is not a contraindication. Significant c**orrection, usually averaging about 30 degrees**, can be obtained through each osteotomy. Osteotomies should be performed at **L2 or below in the presence of kyphosis at the thoracolumbar junction.** The pedicle subtraction technique is preferred with vascular calcifications because it does not lengthen the anterior column, which could risk vascular injury.

Question 142

# sagital imbalance What is each angle in the image? Which angle has been found to most closely correlate with a patient's lumbar lordosis, thoracic kyphosis, and overall sagittal alignment?

Answer 142

Angle A represents pelvic incidence (PI), a constant anatomic relationship between the pelvis and sacrum. Angle B represents pelvic tilt, and angle C represents sacral slope. Pelvic tilt and sacral slope can change depending on the rotation of the pelvis. Pelvic incidence has been found to directly correlate with the magnitude of lumbar lordosis and thoracic kyphosis because it determines the angle at the base of the spine (the lumbosacral junction). To obtain sagittal balance, the remainder of the spine compensates, resulting in the degree of lumbar lordosis and thoracic kyphosis to maintain an upright posture. Thus, PI must be considered in the evaluation of sagittal balance and potential reconstructive procedures. Angle D represents the T1 angle.

Question 142

# sagital imbalance Flat Back Syndrome, what level should you perform the corrective osteotomy

Answer 142

**L2 or L3, it's away from the spinal cord, if you go too distal its hard to get fixation** The safest correction for this malalignment typically is performed away from the spinal cord in the midlumbar spine, most commonly at L2 or L3. The more distal the correction is performed, the more sagittal plane translation of the C7 plumb line with respect to the posterior sacrum. Performing the osteotomy too distally, however, makes it difficult to obtain adequate distal fixation. The clinical photograph and radiograph show an iatrogenic flatback deformity with loss of the normal lumbar lordosis.

Question 143

# sagital imbalance What reduces the rate of psuedoarthrosis at lumbosacral junction

Answer 143

placement of multiple rods, anterior column support, or pelvic fixation reduces pseudarthrosis and instrumentation failure at the lumbosacral junction.

Question 143

# sagital imbalance Risk Factors for PJK? Surgical/Radiographic/Patient specific

Answer 143

Risk Factors and Potential Prevention Strategies for Proximal Junctional Kyphosis and Proximal Junctional Failure: PJK is common, occurring in 10% to 40% of patients; however, PJF requiring revision surgery is much less common, ranging from 1% to 5%

Question 144

Surgical mgmt of thoracolumbar sagital imbalance outcomes:

Answer 144

* may result in excellent outcomes, with reduction in pain and improvement in HRQOL measures. 60% relief of back and leg pain with 40% improvement in disability over 2 years * Risk factors for poorer clinical outcome: depression, increase body mass index, comorbidities, disability, residual deformity (SVA), complications * Coronal balance also has a substantial effect on outcomes

Question 145

# sagital imbalance Rod fracture is commonly associated with

Answer 145

pseudarthrosis. Most common at the lumbosacral junction or at the level of a three-column osteotomy (as high as 30%) Consider improved fixation with the use of multiple rods, anterior column support, or pelvic fixation

Question 146

# sagital imbalance Instrumentation loosening or failure occurs with

Answer 146

Osteoporosis must be optimized preoperatively (typically at least 3 to 6 months of management) Add multiple fixation points, hydroxyapatite-coated screws, cement augmentation

Question 147

# sagital imbalance Psuedoarthosis rates, who's at risk, when whould you suspect

Answer 147

Pseudarthrosis occurs at rates ranging from 5% to 25% Risks: age, kyphosis, positive balance, hip arthritis, smoking, thoracoabdominal approach, incomplete lumbopelvic fixation36,37 Junctional levels are at risk: add interbody or pelvic fixation Consider biologics if indicated to supplement fusion Diagnosis should be considered for persistent or recurrent pain with Rod or screw implant failure Postoperative motion on dynamic imaging CT

Question 148

# sagital imbalance Anterior sagittal balance is the most important and reliable predictor of clinical symptoms and health status.

Answer 148

Disability increases linearly with sagittal imbalance and pelvic compensation. Adverse HRQOL measures include pain, function, and self-image. HRQOL measures worsen with: Increasing SVA (>4 cm) Relative lumbar kyphosis, which is particularly associated with considerable disability Truncal inclination (T1 SPI) and pelvic retroversion (pelvic tilt) outperform the SVA. The T1 pelvic angle, independent of postural compensation The LPA Lumbopelvic mismatch of more than 9° (lumbar lordosis = pelvic incidence ± 9) also is particularly associated with poorer function.

Question 149

ASD and sagittal imbalance are associated with substantial disability.

Answer 149

Below population means and similar to cancers, diabetes mellitus, and cardiac disease Disability worsened particularly with increasing SVA (>10 cm) and decreasing lumbar lordosis

Question 150

sagital balance realigment targets

Answer 150

sagittal realignment targets have been suggested, including a SVA less than 50 mm, pelvic tilt less than 20°, lumbar lordosis = pelvic incidence ± 9°, and T1 SPI less than 0°

Question 151

# sagital imbalance PJK and PJF: definition, rates, patients at risk, surgical considerations, how to avoid?

Answer 151

* PJK is defined as a junctional sagittal Cobb angle of at least 10° or a change of at least 10° from preoperative alignment at the UIV and UIV +1. 10% to 40% * PJF is defined as PJK requiring revision surgery and typically includes instrumentation failure, fracture with instability, or progressive neurologic deficit.low PJF rate of 1% to 5% May be asymptomatic or lead to pain, deformity, or neurologic deficit **Risk factors** Surgical: soft-tissue disruption, combined anterior and posterior approaches, high construct rigidity, magnitude of deformity and correction, and the level of the UIV Patient: older than 55 years, nicotine use, obesity, osteopenia Avoidance is challenging * Avoidance of overcorrection of the sagittal plane * Include levels with baseline segmental kyphosis greater than 5° * Decrease instrumentation stiffness at the junction * Maintain some kyphotic alignment at the junction to match the existing curvature * Use of interspinous tethers or cement augmentation (vertebroplasty) of the UIV +1 or UIV +2 * Reduce soft-tissue disruption at the UIV * Preoperative optimization of osteoporosis

Question 152

Indications for extending ASD fusions to the sacrum rather than stopping in the lower lumbar spine:

Answer 152

* posterior column deficiencies at L5-S1, such as spondylolysis and laminectomy, and deformities extending to the sacrum, such as fixed tilt of L5-S1 or sagittal imbalance. * MRI signal changes in the L5-S1 disk do not preclude stopping the fusion at L5. Some surgeons use diskography or diagnostic facet blocks to evaluate the integrity of the L5-S1 level prior to stopping the fusion at L5. * Long scoliosis fusions stopping at L5 have a significant risk of failure, highlighting the importance of careful selection of fusion levels.

Question 153

When using surgery extending to the pelvis to treat long spinal deformity in adults, the addition of anterior interbody structural support at the lumbosacral junction serves what biomechanical function?

Answer 153

placement of anterior interbody structural support at the lumbosacral junction increases the overall construct stiffness and reduces the strain on posterior instrumentation, thereby reducing the risk of screw pull-out or fracture. The stiffness of the posterior instrumentation actually increases, whereas the actual strength of the instrumentation remains the same. Actual strain measured at an adjacent intervertebral disk to a fusion construct is expected to increase.

Question 154

primary reason for including the ilium in the distal fixation of long instrumentation constructs in adult scoliosis?

Answer 154

improved fusion success across the lumbosacral junction increases when both the sacrum and ilium are included in the posterolateral construct. ## Footnote Studies have shown that when compared with fixation to the sacrum alone, the success rate of fusion across the lumbosacral junction increases when both the sacrum and ilium are included in the posterolateral construct. Curve correction, coronal balance, and pelvic balance are all attended to within the thoracolumbar spine and are not directly related to the pelvic fixation. Fretting and corrosion are a byproduct of metal-to-metal connections.

Question 155

in-situ bending: what is it? During in-situ bending deformity correction, why is it important not to perform major coronal plane correction with this specific maneuver?

Answer 155

* deformity correction techniques involves holding benders to the rods after the set screws have been tightened to improve both sagittal and coronal alignment. * Due to the significant stresses applied at the bone implant interface, the excessive bending force could result in implant insufficiency * In addition, although these maneuvers provide excellent coronal plane correction, they may cause sagittal plane malalignment, losing balance for the sake of radiographic appearance

Question 155

During compression-distraction maneuvers for adult spinal coronal deformity correction, it is important to remember that the compression maneuvers result in --- moments and distraction maneuvers result in --- moments, so care must be taken to preserve sagittal alignment.

Answer 155

lordotic and kyphotic

Question 156

During posterior rod de-rotation correction maneuvers to address adult spine coronal plan deformities, are monoaxial or polyaxial screws recommend and why?

Answer 156

Monoaxial; because polyaxial screws allow for too much movement (and thus less effective on the side of the rod de-rotation

Question 157

Affect on Pulmonary function from ASD

Answer 157

There is no evidence that suggests that an adult patient with previously normal pulmonary function (after skeletal maturity) will experience pulmonary function deterioration due to progression of the curvature without a history of smoking or other pulmonary diseases*

Question 158

what do the lines represent

Answer 158

Central sacral vertical line (CSVL); C7 plumb line (C7PL); the horizontal distance between these two lines is the coronal vertical axis or coronal balance ## Footnote Full-length spine radiographs. A, PA radiograph with a dashed line, which represents the central sacral vertical line (CSVL), and a solid line with an arrow, which represents the C7 plumb line (C7PL). The horizontal distance between these two lines is the coronal vertical axis or coronal balance. Because the C7PL is to the left of the CSVL in this patient, the coronal balance would be described as negative. B, Lateral radiograph with a dashed line, which represents the posterior sacral vertical line (PSVL) drawn from the superoposterior corner of S1, and a solid line with an arrow, which represents the C7PL. The horizontal distance between these two lines is the sagittal vertical axis (SVA) or sagittal balance. Because the C7PL is posterior to the PSVL, the SVA would be described as negative.

Question 159

AIS curves progression?

Answer 159

Most AIS coronal thoracic curves less than 30° tend not to progress; those >30°, progress at a rate of <1° per year

Question 160

Bracing for ASD

Answer 160

Bracing may provide benefit for temporary exacerbation of symptoms, but is not recommended as it has not shown the ability to prevent curve progression, and may actually exacerbate deconditioning

Question 161

Deformity Correction in ASD: Rod derotation

Answer 161

Rod derotation is a commonly used technique for the reduction of coronal curvatures ## Footnote Rod derotation is a commonly used technique for the reduction of coronal curvatures. In theory, the technique is simple and effective at rotating a scoliotic helix toward the sagittal plane. The amount of derotation at individual vertebrae in the axial plane may be limited in a pure rod rotation correction maneuver; however, this is disputed by some who suggest that considerable apical vertebral rotation occurs in posterior derotation maneuvers and in the overall correction of a coronal deformity into the sagittal plane.41 Rod derotation often is described via the posterior approach but also may be performed via open anterior and thoracoscopic approaches. For segmental derotation, after placement of pedicle screws at planned levels, the concave rod is placed initially as usual. The surgeon should identify the proximal and distal neutral vertebrae and secure them with the use of derotation devices to act as a counterforce for the rotatory maneuvers (Figure 8). Then, rod derotation and translation are applied to reduce the rod into the screw tulips. The convex derotation device should be forced downward and medially as the concave device is forced upward by a pulling vector. Concurrently, the neutral vertebrae should be forced toward the contralateral side, and more downward force can be applied across the rib hump (if present).42 For en bloc derotation, the derotation devices are attached to all intervening levels. The entire segment can connect through a locking device and, therefore, provide simultaneous rotation of the entire segment.

Question 162

Deformity Correction in ASD: what is cantilever beam

Answer 162

The concept of a cantilever beam fixation system refers to a short-segment fixation technique generally confined to a single level above and below a pathologic spinal segment.43 The most straightforward application of the rod cantilever technique involves the placement of screws into the vertebral bodies spanning a single disk space. The most practical application for deformity correction surgery is the use of cantilever beam fixation in a multisegmental fashion.44 The vertical rod or plate segment then acts to transmit the load back through another cantilever beam to the spinal column. After bending to the desired contour for optimal sagittal alignment, rods are connected sequentially to each pedicle screw or hook one by one. As the screws are connected to the rods, the spine begins to take the shape of the rods and is brought into the desired sagittal and coronal alignment. Specifically, for coronal deformities, lateral translational deformities may either be reduced or prevented in the thoracic and lumbar spine by toeing-in of the screws, applying rigid cross-fixation of the longitudinal rods, adding levels of spinal segmental fixation, or incorporating any combination of these techniques. The corrective forces generated by the cantilever bending technique ultimately are limited by the reliability of bone-implant interfaces

Question 163

ASD deformity correction: direct vertebral rotation

Answer 163

direct vertebral rotation involves correction of vertebral rotation via the application of a posterior force in the direction opposite that of the deformity.48 The torque is applied to the pedicle screw with the use of long screw derotators that are placed on the concavity and convexity of the curve. This maneuver corrects intervertebral rotation, allowing for three-dimensional correction. The direction of direct vertebral rotation is opposite to the direction of vertebral rotation. For example, if a right thoracic curve is present, apical and juxta-apical vertebrae are rotated clockwise in the transverse plane. These maneuvers generally are reserved for pediatric patients and are uncommonly used in the management of ASD.

Question 164

ASD deformity correction: Compression-distraction forces

Answer 164

Compression-distraction forces can be applied throughout all segments of the instrumented construct to improve coronal and sagittal alignment.45 In general, the intervertebral disks are opened more on the convex side, and the compression force is applied along the convexity of the curve.46 On the contralateral side, the opposite is true for the distraction force. The compression maneuvers result in lordotic moments, and the distraction maneuvers result in kyphotic moments; therefore, care must be taken to preserve sagittal alignment

Question 165

contraindication for posterior decompression (with or without fusion) for myelopathy

Answer 165

fixed kyphosis >10 deg ## Footnote Although cervical instability is a contraindication to posterior decompression alone, segmental instability in the myelopathic cervical spine can be addressed with concomitant posterior fusion with instrumentation. Cervical lordosis represents the ideal scenario for posterior decompressive procedures for myelopathy (laminectomy and laminoplasty) because compression from anterior osteophytes, if present, is relieved as the spinal cord migrates posteriorly. The anteroposterior diameter of the spinal canal does not have an impact on the selection of surgical approach. Posterior unroofing-type procedures in kyphotic cervical spines, however, are ineffective because anterior impingement on the spinal cord will remain; therefore, kyphosis of more than 10 degrees is considered a contraindication for posterior decompression.

Question 166

Degenerative spondylolisthesis of the cervical spine is most commonly seen at which of the following levels?

Answer 166

Degenerative spondylolisthesis of the cervical spine is seen almost exclusively at C3-4 and C4-5; this is in contrast to degenerative changes, which are most commonly seen at C5-6 and C6-7.

Question 167

congenitally small spinal canal with secondary multilevel degenerative changes causing stenosis and cord compression across multiple segments, including directly posterior to the vertebral bodies. what does this patient need

Answer 167

cervical laminoplasty, if lordosis preserved the patient's cervical lordosis is preserved, a posterior procedure such as laminoplasty or laminectomy would allow the cord to fall away from the anterior pathology and afford decompression. A multilevel diskectomy may address the cord compression at the disk level, but not posterior to the bodies, and most likely would be inadequate

Question 168

surgical dissection should not enter the plane between the trachea and the esophagus and excessive retraction should be avoided to prevent injury to the?

Answer 168

The recurrent laryngeal nerve lies between the trachea and the esophagus. The vagus nerve lies in the carotid sheath. The sympathetic trunk lies anterior to the longus colli muscles. The hypoglossal and superior laryngeal nerves are both at risk during the exposure but are not located between the trachea and the esophagus.

Question 169

What is the most common adverse postoperative complication of laminoplasty for multilevel cervical spondylotic myelopathy?

Answer 169

A **30% to 50% loss of cervical range of motion** is reported postoperatively in most patients following cervical laminoplasty. Inadvertent closure of the laminoplasty does occur but is rare. Laminoplasty is advocated in lieu of laminectomy to prevent progressive kyphosis and can effectively decompress the spinal cord. * C5 nerve root palsies are a poorly understood but rare complication of surgical decompression for cervical spondylotic myelopathy.

Question 170

contraindication to laminoplasty in a patient with cervical spondylotic myelopathy?

Answer 170

Laminoplasty or any posterior decompressive procedure is contraindicated in patients with cervical spondylotic myelopathy and cervical kyphosis. The residual kyphotic posture of the cervical spine results in persistent spinal cord compression.

Question 171

Who is at risk for airway complications after ACDF/Cervical procedures? What are the recommendations

Answer 171

Airway complications after anterior cervical surgery can be a catastrophic event necessitating emergent intubation for airway protection. Multilevel surgeries requiring long intubation and prolonged soft-tissue retraction as well as preexisting comorbidities may predispose a patient to postoperative airway complications. Sagi and associates reported that surgical times greater than 5 hours, blood loss greater than 300 mL, and multilevel surgery at or above C3-4 are risk factors for airway complications. In surgical procedures with the aforementioned factors, serious consideration should be given to elective intubation for 1 to 3 days to avoid urgent reintubation.

Question 172

What structure is most at risk with anterior penetration of C1 lateral mass screws?

Answer 172

**internal carotid artery** that lies immediately anterior to the arch of C1 that is particularly at risk by anterior penetration of C1 lateral mass or C1-C2 transarticular screws. The internal carotid artery lies posterior to the pharynx. **Vertebral artery ** injury is one of the most feared complications associated with screws in the C1/C2 region. This structure, however, is *lateral and posterior at the C2 level and then penetrates the foramen transversarium of C1 to lie cephalad to the arch of C1 before entering the foramen magnum. * The external carotid artery and the glossopharyngeal nerve are not at risk with this method of fixation.

Question 173

hoarseness due to vocal cord paralysis after anterior cervical diskectomy and fusion

Answer 173

**Equivocal b/t R and L approaches** no clinical evidence to suggest that laterality of approach for anterior cervical surgery makes any difference in the incidence of vocal cord paralysis ## Footnote It has been traditionally taught that a left-sided approach to the anterior cervical spine is associated with a lower incidence of injury compared to the right-sided approach. This is due in part to the anatomic differences in the path the recurrent laryngeal nerve (RLN) takes on the right as compared to the left. Both nerves ascend in the tracheoesophageal groove after branching off the vagus nerve in the upper thorax. The left-sided RLN loops around the aortic arch and stays relatively medial as compared to the right-sided RLN which loops around the right subclavian artery and is somewhat more lateral at this point, and therefore is theoretically more vulnerable as it ascends toward the larynx before becoming protected in the tracheoesophageal groove. Furthermore, the variant of a nonrecurrent inferior laryngeal nerve branching directly off the vagus nerve at the level of the midcervical spine is much more common on the right than the left. Despite this reasoning, there has been no clinical evidence to suggest that laterality of approach for anterior cervical surgery makes any difference in the incidence of vocal cord paralysis. Furthermore, two recent studies have shown that the incidence of RLN injury and vocal cord paralysis is equal with either side of approach.

Question 174

density changes are not observed on radiographs until a loss of ----- of bony architecture occurs.3 Radiographic bony changes from infection may not be observed for up to ---- weeks.

Answer 174

density changes are not observed on radiographs until a loss of **30% to 50%** of bony architecture occurs.3 Radiographic bony changes from infection may not be observed for up to **8 **weeks.

Question 175

MRI is performed if concern for an unstable spine injury exists and to evaluate the ???. T2 weighted MRIs should be evaluated for???. T1 weighted MRIs should be evaluated for ???

Answer 175

MRI is performed if concern for an unstable spine injury exists and to evaluate the **PLC.** T2-weighted MRIs should be evaluated for **signal intensity at the PLC**, and T1-weighted MRIs should be evaluated for** ligamentous discontinuity**

Question 176

DDD on CT and MRI what will you see on imaging.

Answer 176

The vacuum phenomenon on CT scans, which is observed as air in the disk space, may indicate advanced disk degeneration and mobility in that segment. On T2-weighted MRIs, decreased water and proteoglycan content manifests as loss of disk hyperintensity

Question 177

Modic Changes

Answer 177

MRI is the best imaging modality for assessing degenerative progression at the end plates. Modic end plate changes describes the progression of involvement of the end plates.16 Type 1 changes are observed as hypointense on T1-weighted MRIs and hyperintense on T2-weighted MRIs, signaling marrow inflammation and edema. Type 2 changes are observed as hyperintense on T1-weighted MRIs and isointense or slightly hyperintense on T2-weighted MRIs, indicating fatty replacement of marrow. Type 3 changes are observed as hypointense on T1- and T2-weighted MRIs, signaling trabecular microfracture and sclerosis.

Question 178

MRI is recommended for patients with adolescent idiopathic scoliosis who have an ???

Answer 178

MRI is recommended for patients with adolescent idiopathic scoliosis who have an atypical, left-sided thoracic curve; pathologic reflexes; hairy patches concerning for spina bifida; or syndromic pathology.

Question 179

Inferior outcomes in adults with spinal deformity,

Answer 179

In adults with a spinal deformity, a** sagittal imbalance greater than 5 cm**, **a coronal imbalance greater than 4 cm**, and **pelvic incidence–lumbar lordosis mismatch greater than 10°** are associated with inferior outcomes

Question 180

Neoplasm Imaging: Bony changes may not be observed until? Lytic vs Blastic changes: Neoplastic processes most often appear as? CT is helpful for?

Answer 180

* Radiographic bony changes may not be observed until as much as 40% bony erosion occurs. Lytic changes: Lung, thyroid, and renal lesions Blastic changes: prostate and breast cancer Gadolinium-enhanced MRI is the preferred imaging modality, defining the extent of tumor and neural compression. Full-length spine images should be obtained to ensure all noncontiguous lesions are identified. Neoplastic processes most often appear hyperintense on T2-weighted MRIs and hypointense on T1-weighted MRIs. CT is particularly useful for evaluating osteoblastic processes and to assess the extent of bony erosion. CT also aids in evaluating for osteoid osteoma.

Question 181

Infection spine Imaging: Abnormal radiographic findings? MRI necessary for what? How does TB look?

Answer 181

Abnormal radiographic findings, which may include paraspinal soft-tissue swelling, narrowing of the disk space, end plate erosion, focal deformities after chronic infection, and fusion in late stages, may not be observed for up to 8 weeks after the onset of the disease process. MRI is the most sensitive and specific imaging modality and helps delineate osteomyelitis from tumor. Epidural abscesses, which may be a surgical emergency, may appear hypointense on T1-weighted MRIs and hyperintense on T2-weighted MRIs with gadolinium rim-enhancement Vertebral osteomyelitis may be confused for a tumor or trauma because it commonly appears hyperintense and hypointense on T2-weighted MRIs and T1-weighted MRIs, respectively Tuberculosis is a less common infectious presentation and may be suggested if vertebral body compression and severe angular kyphosis are observed on radiographs. Dissimilar to pyogenic infections, sparing of the disk space is present early in the disease process. Similar to other infections, MRI is the preferred imaging modality, displaying a low signal intensity in affected areas on T1-weighted MRIs and a high signal intensity in affected areas on T2-weighted MRIs. Smooth-walled abscesses with septa also may be observed.

Question 182

# Facet Dislocations: Pt w/ facet dislocation, tx strategy for awake vs obtunded? How much weigh is ok?

Answer 182

If awake, gardner wells tong traction. If can't get reduction MRI then open reduction If obtunded, MRI then open reduction. 50lbs of traction is traditional limit though more can be safely used. ## Footnote In patients with facet dislocations and an incomplete neurologic deficit, early decompression of the canal via reduction of the dislocation generally is considered safe if the patient is alert and can cooperate. However, patients who cannot cooperate with serial neurologic examinations during the reduction are at risk for increased deficit secondary to herniated nucleus pulposus, and **MRI should be performed prior to either closed or open reduction.** - Gardner wells tong traction Cotler and associates reported on the use of awake skeletal traction to reduce facet fracture-dislocations in 24 patients. Seventeen patients required more than 50 pounds of traction (the “traditional” limit) to achieve reduction. More than 100 pounds of traction was safely used in one-third of the patients in this study. A cadaver study has supported the safe use of traction with weights in excess of 100 pounds.

Question 183

Neurogenic shock management

Answer 183

**Bradycardic, loss of sympathetic tone to the heart. Not responding to hypotension with tachycardia. Adequate urine output. Swan ganz catheter to differentiate and vasopressors** ## Footnote The patient’s heart rate is not responding to hypotension with tachycardia, as would be expected in the event of hypovolemic shock. Additionally, the adequate urine output suggests proper fluid resuscitation. Instead, she is bradycardic, possibly indicating neurogenic shock and loss of sympathetic tone to the heart. A Swan-Ganz catheter should be used to help differentiate these problems and guide appropriate fluid resuscitation and use of vasopressor agents.

Question 184

C spine clearance: Failure to achieve early spinal clearance in an unconscious blunt trauma patient predisposed the patient to

Answer 184

Failure to achieve early spinal clearance in an unconscious blunt trauma patient predisposed the patient to increased morbidity secondary to the prolonged used of cervical immobilization. **four significant predictors of collar-related ulcers ** ICU admission, mechanical ventilation, the necessity for cervical MRI, and the time to cervical spine clearance and collar removal. The risk of pressure-related ulceration increased by 66% for every 1-day increase in Philadelphia collar time and this highlights the need for definitive C-spine clearance

Question 185

Burst Fx is cause from

Answer 185

**Axial load,** radiographic hallmark of a burst fracture is compression of the posterior cortex of the vertebral body with retropulsion of bone into the spinal canal. AP radiographs often show widening of the interpedicular distance with a fracture of the lamina.

Question 186

Halo pin site infection vs loosening

Answer 186

One of the most common complications of halo device fixation is pin loosening. In adults, pin loosening can occur in up to 36% of patients and most commonly occurs in the anterior pins. If there is no infection present, a loose pin can be managed by simply retightening the screw one to two turns. Infection at the pin site is the second most common complication of the halo device, occurring in about 20% of patients. Infection can be either superficial or deep. Superficial infections can be treated with oral antibiotics and wound care at the pin site. Pin loosening does not always occur with pin site infection. The infection can be treated with or without removing the pin. If a deep infection develops, the pin should be removed. If an abscess develops, parenteral antibiotics and drainage of the abscess may be necessary. A new pin may be placed in a new position. Other complications from halo fixation include skin breakdown and intracranial penetration

Question 187

Type IIa Hangman's fx

Answer 187

**classic treatment is halo vest immobilization**. Traction should be avoided in type IIa injuries because of the risk of overdistraction. A lesser form of immobilization such as a hard collar or a Minerva jacket can be used for nondisplaced (type I) fractures. Surgery generally is reserved for type III fractures (includes C2-3 facet dislocation), or extenuating circumstances such as multiple trauma or other fractures of the cervical spine that require surgical stabilization.

Question 188

C1 Jefferson Burst fx on AP

Answer 188

classic C1 burst (Jefferson) fracture, noted that spread of the lateral masses of more than 7 mm is indicative of a transverse ligament rupture.

Question 189

Dens fx tx

Answer 189

* Type 1 fractures typically can be treated nonsurgically with 6 to 8 weeks of immobilization with a semi-rigid cervical orthosis. * Type II: op vs non op. Management with the halo vest usually is considered if the initial dens displacement is less than 6 mm, the reduction is performed within 1 week of the injury and is able to be maintained, and the patient is younger than age 60 years. Halo vest immobilization can lead to a healing rate of more than 90%. Posterior surgical fusion techniques provide high fusion success rates but do so at the expense of cervical rotation. Up to 50% of rotation is lost with these techniques. Anterior odontoid single screw fixation is often tolerated better than skeletal halo fixation and also is noted to preserve the normal rotation at C1/C2. Studies have shown less of a malunion and nonunion rate in the treatment of type II odontoid fractures with anterior odontoid screw fixation. Osteoporosis, short neck and barrel-chested anatomy, and fractures that are more than 4 weeks old preclude anterior odontoid fixation. * Type III: fx line extends through body of axis, Nondisplaced, deep type III fractures generally are treated with skeletal halo fixation. Deep, displaced, and angled type III fractures can be treated with closed reduction and skeletal halo fixation. Shallow type III fractures are sometimes amenable to anterior odontoid screw fixation.

Question 191

c spine facet fx/dislocation is hard to manange in a halo because

Answer 191

Facet fx/dislocation hard to manage in a halo Facet joint fracture or dislocation is associated with an increased risk of loss of alignment with halo vest immobilization. The recently published study by van Middendorp and associates confirms the findings of prior studies that facet fracture-subluxations or dislocations are difficult to immobilize with a halo vest due to a limited ability to maintain reduction and alignment. C2 pars fractures, burst fractures, and C1 lateral mass fractures can be managed with halo vest immobilization

Question 192

TAL injury management:

Answer 192

injuries of the transverse atlantal ligament into two categories. Type I injuries are disruptions through the substance of the ligament itself. Type II injuries render the transverse ligament physiologically incompetent through fractures and avulsions involving the tubercle of insertion of the transverse ligament on the C1 lateral mass. Type I injuries are incapable of healing without supplemental internal fixation. Type II injuries can be treated with a rigid cervical orthosis with a success rate of 74%. Surgery may be required for type II injures that fail to heal with 3 to 4 months of nonsurgical management. ## Footnote In two different biomechanical studies performed in both bovine and human cadaveric spines, all posterior techniques of stabilization were found to be superior to anterior plating in flexion-distraction injuries of the cervical spine. These injuries usually have an intact anterior longitudinal ligament that allows posterior fixation to function as a tension band. Anterior plating with grafting destroys this last remaining stabilizing structure and does not allow for a tension band effect because all of the posterior stabilizing structures have been destroyed with the injury. In clinical practice, however, anterior plating can be effective in the treatment of this injury with appropriate postoperative orthotic management.

Question 193

Ankylosed Spine Injury management:

Answer 193

**Get CT** scan if xrays negative; In patients with trauma in the setting of ankylosing spondylitis and cervicothoracic kyphosis, it is **highly recommended that the neck be maintained in the pre-morbid flexed position until definitive management can be performed.** . Extension of the injured spine in a patient with ankylosing spondylitis can lead to neurologic injury and/or displacement of a previously aligned fracture. ## Footnote Ankylosing spondylitis is a chronic inflammatory disease that is characterized by ossification of the spinal column with an associated progressive kyphotic deformity of the spine. The deformity therefore becomes the native position for the patient with ankylosing spondylitis

Question 194

A paracentral disk herniation at L4-L5 most commonly results

Answer 194

Trendelenburg gait: glute med weakness. L5 nerve root.L5 radic from L4-5 Paracentral disk herniation A paracentral disk herniation at L4-L5 most commonly results in an L5 radiculopathy and thus weakness of the gluteus medius.

Question 195

A paracentral herniation at L5-S1 most commonly affects the ??? nerve root.

Answer 195

S1 nerve root

Question 196

L4 nerve root radiculopathy can come from:

Answer 196

A paracentral herniation at L3-L4, a central herniation at L3-L4, and a far lateral herniation at L4-L5 all affect the L4 root.

Question 197

TLSO lowest level of immobilization

Answer 197

TLSO: lowest level of immobilization is** L3-4.** L4-5 &L5-S1 have same or increased mobility when wearing a TLSO.

Question 198

Halo Pins: how much torque for aldults and kids

Answer 198

8lbs torque adults; 6 lbs kids. Clinically safe and effective in lowering incidence of pin loosening and infection

Question 199

Relationship of nerves in retroperitoneal approach to lumbar spine:

Answer 199

* Sympathetic trunk runs longitudinally along medial border of psoas. * Ilioinguinal n upper lateral border of psoas * Genitofemoral nerve, more lateral on psoas.

Question 200

Thickest bone of the occiput is

Answer 200

Thickest bone of the occiput is at the level of the external occipital protuberance

Question 201

Aging spine, primary change is

Answer 201

primary change that takes place in the aging spine is degeneration of the lumbar disks and loss of the overall lumbar lordosis. This also may be associated with osteopenic-related compression fractures. With these changes, the sagittal vertical line moves anteriorly relative to the sacrum; cervical scoliosis is uncommon and not part of the normal aging process. Overall kyphosis in the thoracic spine gradually increases, but the coronal balance remains essentially the same unless scoliosis develops.

Question 202

Afferent pain fibers to the lumbar facet joints arise from

Answer 202

medial branch nerves originating from the next two cephalad levels. Therefore, innervation of the L3-L4 facet joint arises from the L2 and L3 medial branch nerves. This effect should be taken into account when considering a medial branch block or facet denervation. The medial branch nerve arises from the dorsal ramus of the exiting nerve root.

Question 203

Vertebral artery path in c-spine when entering skull

Answer 203

The vertebral artery traverses through the arcuate foramen after exiting the lateral aspect of C1 and before entering the skull. The foramen usually is not fully formed, but a complete foramen such as this one has been reported in up to 18% of patients.

Question 204

Retrograde ejaculation is a sequela of injury to

Answer 204

**superior hypogastric plexus**. The structure needs protection, especially during anterior exposure of the **lumbosacral junction**. The use of monopolar electrocautery should be avoided in this region. The ideal exposure starts with blunt dissection just to the medial aspect of the left common iliac vein, sweeping the prevertebral tissues toward the patient’s right side. ## Footnote Although erectile dysfunction can be seen after spinal surgery, it is not typically related to the surgical exposure because erectile function is regulated by parasympathetic fibers derived from the second, third, and fourth sacral segments that are deep in the pelvis and are not at risk with the anterior approach.

Question 205

The angle of the mandible is at ?; the hyoid is at ?; the superior portion of the thyroid cartilage is ?; and the cricoid cartilage is at ?. The carotid tubercle is usually located at the level of ?

Answer 205

The angle of the mandible is at C1-C2; the hyoid is at C4; the superior portion of the thyroid cartilage is C4-C5; and the cricoid cartilage is at C6. The carotid tubercle is usually located at the level of C6

Question 206

Segmental root level palsy after laminoplasty:

Answer 206

postoperative incidence of** C5 root palsy after laminoplasty ranges from 5% to 12%**. Other roots also may be affected. The palsies tend to be motor dominant, although sensory dysfunction and radicular pain are also possible. The palsy may arise during the immediate postoperative period or up to 20 days later. C5 may be preferentially involved because it is at the apex of the cervical lordosis. Recovery usually occurs over weeks to months.

Question 207

Structure at risk for anterior exposure of C2-3?

Answer 207

The **hypoglossal nerve** exits from the ansa cervicalis at approximately the C2-3 level and can be injured during retraction up to the C2 level. The superior laryngeal nerve lies at about C4-5

Question 208

Halo fixation: where do you want to place your pins?

Answer 208

A relatively safe zone for anterior pin placement is located **1 cm above the orbital rim and superior to the lateral two thirds of the orbit.** This position avoids the supraorbital and supratrochlear nerves and arteries over the medial one third of the orbit. The more lateral positions in the temporal fossa have very thin bone and can interfere with the muscles of mastication. Posterior pin site locations are less critical; positioning on the posterolateral aspect of the skull, diagonal to the contralateral anterior pins, is generally desirable.

Question 209

C5-6 surgical approach, what is the muscle encountered?

Answer 209

The omohyoid muscle crosses the surgical field from inferior lateral to anterior superior traveling from the scapula to the hyoid bone and may need to be transected. The posterior digastric crosses the field as well but higher near C3-4.

Question 210

Highest tensile modulus to resist torsional, axial, and tensile loads in spine?

Answer 210

The annulus fibrosis has a multilayer lamellar architecture mode of type I collagen fibers. Each successive layer is oriented at 30 degrees to the horizontal in the opposite direction, leading to a “criss-cross” type pattern. This composition allows the annulus, which has the highest tensile modulus, to resist torsional, axial, and tensile loads.

Question 211

inverted radial reflex

Answer 211

inverted radial reflex is a hypoactive brachioradialis reflex in combination with involuntary finger flexion. It is a spinal cord “release” sign and is associated with upper motor neuron pathology as seen in cervical stenosis with myelopathy. Radiculopathy is characterized by a diminished reflex but no finger flexion. Peripheral neuropathy is not associated with any reflex change.

Question 212

Shoulder abduction relief sign

Answer 212

The shoulder abduction relief (SAR) sign (relief of upper extremity pain with shoulder abduction) is virtually pathognomic of cervical radiculopathy because this maneuver results in relaxation of a compressed and/or inflamed cervical nerve root. The SAR sign is the converse analog of the straight leg raising sign in the lumbar examination for lumbar radiculopathy, as it relieves tension in the nerve root, thereby relieving symptoms.

Question 213

tine's sign at levator scapulae is indicative of

Answer 213

Tinel’s sign at the levator scapulae, if present, is indicative of an **upper cervical (C3 or C4)** radiculopathy.

Question 214

Most common physical exam findings in myelopathy

Answer 214

Hoffman (80%)> hyperreflexia (no difference in prevelance in ppl w/ and w/o myelopathy), babinski & clonus 1/3 of ppl w/ myelopathy.

Question 215

What condition does this patient likely suffer from?

Answer 215

The radiograph and sagittal T2-weighted MRI scan show multilevel degenerative changes and subaxial subluxations with anterolisthesis at C3-C4 and C4-C5 and retrolisthesis at C5-C6. In addition, there is evidence of midcervical kyphosis. Such findings are often seen in patients with rheumatoid arthritis.

Question 216

TB spine: where is it commonly found?

Answer 216

Tuberculosis of the spine is seen in 50% to 60% of skeletal disease and is most commonly found in the lower thoracic or upper lumbar spine. Typically two or more adjacent bodies are involved as seen in this MRI scan. The disk space is narrowed but still relatively preserved as opposed to pyogenic infections (black arrow). Epidural extensions often spread from vertebrae to vertebrae (white arrow); however, the posterior elements are not frequently involved (arrowhead).