Miller's Review Spine Flashcards
Ortho spine review
SPECT CT commonly used to evaluate ___
Spondylolysis. SPECT is a bone scan overlying a CT scan
Most common lumbar levels of spondylosis
L4-5 > L5-S1 > L3-L4
MRI findings in lumbar spondylosis
As the nucleus pulposis degenerates, you get decreased T2 signal in the disc (dark disc disease)
Physical exam maneuvers for discogenic back pain
Straight leg raise with radicular symptoms and femoral stretch with radicular symptoms
1st step in pathway of disc degeneration
Tear in annulus fibrosus
Nerve block for facetogenic back pain
Medial branch of dorsal rami
Most common direction for disc herniations
Posterolateral, adjacent to the stout posterior longitudinal ligament
Most common nerve compressed in lumbar disc herniation?
L5 root. L4-L5 disc herniation is the most common, posterolateral is most common, so it compresses the traversing L5 nerve root (not the exiting L4 nerve root at the L4-L5 level)
What nerve root is likely compressed at this disc herniation at L4-L5?
This is a far lateral herniation that would compress the EXITING nerve root at L4-L5, which is L4.
Indications for operative management in lumbar disc hernation?
Cauda equina, weakness or failure of conservative management. DO NOT FUSE unless they have instability
Indications for fusion with herniatic lumbar disc
Multiple recurrent HNP
Treatment of single recurrent herniated disc?
Microdiscectomy without fusion
Outcomes in far lateral disc herniation treated with Wiltse approach
Not as well as central disc herniation treatment, persistent radiculopathy in some
How does vascular claudication differ from neurogenic claudication
In vascular claudication patients have no pain when standing still, they have pain when walking up a hill (better going uphill in neurogenic, worse going down hill), pain on stationary bike and pain starts in feet (buttock in neurogenic)
Surgical management of lumbar stenosis
Don’t need to fuse unless evidence of instability or severe foraminal stenosis that may render the segment unstable with facet resection
SPORT trial for lumbar stenosis
Surgery did better than non-op group
Pediatric spondylolysis prognosis
If Meyerding grade I or II by skeletal maturity, they do not slip more. Grades III and IV tend to progress.
6 types of spondylolisthesis
Dysplastic (presents ages 4-6 w/high grade slip, kyphosis and neurologic sx), isthmic, degenerative, traumatic, pathologic and iatrogenic
Treatment of high grade dysplastic spondylolisthesis in a child?
Fusion. Can do L5-S1 in situ fusion which leaves residual deformity, but reduces risk to L5 nerve root with reduction of the slip
When do adolescents with low grade isthmic spondylolysis get nerve compression symptoms?
As they age, the disc degenerates and they get “up down” foraminal stenosis
Surgical treatment of adult isthmic spondylolisthesis
Interbody fusion improves rates of fusion
Most common level for degenerative spondylolisthesis
L4-L5
Cause of degenerative spondylolisthesis
Incompetent facet joints lead to spondylolisthesis, compression is usually central or lateral recess
Surgical treatment of degenerative spondylolisthesis
Decompression only if <5mm movement on flex-ext views. If unstable, fusion
Most common level for isthmic spondylolisthesis
L5-S1
PVR threshold in cauda equina
<200cc is not cauda equina, >500 = cauda equina, in between we don’t know
Best study to evaluate recurrent HNP
MRI WITH CONTRAST, scar will enhance with contrast, recurrent disc will not light up
Approach with highest risk of nerve root injury in lumbar spine surgery
TLIF approach
% of facet to keep to limit instability when not fusing
Maintain >50% of both facets
What decreases the risk of pseudoarthrosis after lumbar fusion?
Instrumentation
Treatment of post-discectomy diskitis
MRI with contrast, if it lights up in the disc, treatment is IR biopsy and medical management
Key physical exam finding to differentiate thoracic myelopathy from cervical myelopathy
Thoracic myelopathy will have UMN signs in the lower extremities, but not in the upper extremities like cervical myelopathy
Surgical treatment of thoracic myelopathy
May require thoracotomy because you can’t retract to cord at the thoracic level enough to get at the disc space
Indication for operative management of osteodiskitis
Impending mechanical/neurological instability, concomitant epidural abscess, unable to get IR biopsy or failure of full medical management
Continue antibiotics while drains in?
Not indicated
Most common region of spine involved in metastatic disease
Thoracic (70%), lumbar (20%), cervical (10%)
Most commonly involved column in spinal mets?
Anterior column
Next step in patients with an intradural spinal mets
Brain MRI to look for primary lesion causing drop down mets
Treatment of lymphoma in the spine?
Typically non-surgical, it is very radiosensitive
Indications for surgical stabilization of the spine in metastatic disease
Cord compression, unrelenting pain despite max treatment, need for open biopsy, mechanical instability and radio-insensitive tumors (renal cell)
Primary tumors of the spine seen in the posterior elements?
ABC, osteoid osteoma and osteoblastoma
Operative management of spine ABC
En bloc resection may not be possible, may need extended curettage and grafting +/- post op XRT if you can’t get it all (worry is that these can dedifferentiate into sarcoma after XRT)
What is your diagnosis?
Hemangioma. The prison bars on the sagittal and polka dots on the axial are characteristic.
Management of vertebral plana in eosinophilic granuloma
Bracing to prevent kyphosis, can do low dose XR; however, vertebrae may reconstitute up to 30%
Most common axial site of giant cell tumor?
Sacrum, then clivus
Treatment of giant cell tumor in the spine?
Excision and bone grafting (has high local recurrence rate), no XRT due to malignant transformation risk
Surgical management of chordoma
Resection and reconstruction, no XRT because it is radioresistant
Most common site of thoracolumbar fractures
T11-L2 where fixed thoracic spine transitions to flexible lumbar spine
Prognosis of sacral sparing spinal cord injury?
Residual sensation around S2-S5 = incomplete cord injury and may get more recovery than a complete ASIA A.
Diagnosis of vertebral compression fractures
Anterior column <50% height loss, middle column intact.
Treatment of VCF
Nonsurgical, kyphoplasty if fail initial non-op management
Diagnosis of burst fracture
Fracture of anterior and middle columns +/- posterior column involvement.
Risk of lamina fracture in burst fracture?
Possible dural tear and nerve entrapment (77%), need to be careful during initial approach
Treatment of burst fracture
If intact neuro and PLC -> bracing/non-op regardless of retropulsion or vertebral height loss. If neuro deficit, fracture dislocation or PLC injury w/progressive kyphosis -> surgery
ASIA classification
A) complete B) sacral sparing C) 50% <3/5 strength D) 50% 3 or more/5 strength E) Normal
Treatment of bony vs. ligamentous chance fracture
Bony = brace in extension. Ligamentous = less likely to heal = surgery
Spine GSW antibiotic indications
No abdominal injury = PO. Solid organ injury = PO abx. Hollow organ injury = IV abx 7-14 days + tetanus.
Indications for operative management in spine GSWs
Abdominal organ injury or progressive neuro deterioration. If bullet is in canal and T12 or above, observe. If below T12 consider removing if residual neuro sx
Spinal cord syndrome with ipsilateral motor loss and contralateral loss of pain and temperature sensation? Prognosis?
Brown-Sequard. Best prognosis for ambulation, 99% will regain ambulatory status.
Spinal cord syndrome in elderly with hyperextension and UE involvement > LE.
Central cord
Spinal cord syndrome with associated vascular injury, motor loss, proprioception preserved? Prognosis?
Anterior cord, seen in large aortic reconstructions. Worst prognosis for ambulation.
Spinal cord syndrome with motor intact and loss of proprioception?
Posterior cord syndrome (Tabes dorsalis from syphilis)
Autonomic dysreflexia
Thoracic injury above T5 with severe hypertension, flushing, sweating, blurred vision caused by obstructed urinary catheter or fecal impaction. Can also present after an undiagnosed fracture.
Where should the C7 plumb line fall?
Center of C7 body line should cross T12/L1 junction and posterior corner of L5-S1. Poor balance becomes an issue when 7cm anterior.
What are lumbar lordosis, sacral slope, pelvic tilit and pelvic incidence? Which value is fixed?
Pelvic incidence is a fixed value.
Calculating pelvic incidence
PI = SS + PT
LL – PI goal with deformity correction
Within 10 degrees of each other
PT goal with deformity correction
<25 degrees
SVA target in deformity correction
0 in young patients, more in elderly because it can lead to PJK if at 0
Contraindication for Ponte osteotomy
Non-mobile disc. Correction in this osteotomy happens through the disc, so it wont work if the disc is degenerative. You must do a PSO or VCO in this group.
What parts are removed in a Ponte osteotomy?
½ of the lamina and bilateral superior facets, this will get you 10 degree correction per level
What parts are removed in pedicle subtraction osteotomy?
Pedicles and osteotomy converges at anterior cortex of vertebral body. Gets 25-30 degrees correction/level.
Percentage of lumbar stenosis patients with tandem stenosis?
20% will have cervical myelopathy
Definition of congenital stenosis and absolute stenosis?
Congenital is <10mm SAC, absolute <8mm SAC
Lhermitte’s sign
Shock sensations down the back with neck flexion, seen in cervical myelopathy
Torg-Pavlov ratio
Measurement of vertebral body to spinal canal in cervical spine, if <0.8, then suggests congenital stenosis (blue in picture)
Score that helps determine operative timing and outcomes in cervical myelopathy?
JOA <14 = poor outcome with operative mangement, consider surgery in patients with scores between 4-14
Nurick classification
0 = root sx only, 1 = cord compression, normal gait, 2= gait impaired but employed, 3= gait impaired, not employed, walks unassisted, 4 = unable to walk without assistance, 5 = wheelchair bound
Predictors of poor outcome in operative management of cervical myelopathy
JOA <14 (most important), cord signal change (snake eyes shown below), older age, smoking, medical comorbidities and SAC <13mm
Algorithm for operative management of cervical myelopathy
Kyphosis >10 degrees needs anterior, 3+ levels needs posterior too. Kyphosis <10 degrees can go anterior or posterior, anterior if 1-2 levels, anterior & posterior or posterior alone if 3+ levels, may also consider laminoplasty in select patients
K line
Line drawn from top to bottom of decompression. If line intersects vertebral body, there is too much kyphosis and you need to do a decompression and correction from the front.
Anterior vs. posterior c-spine surgery comparision
Higher rate of infection with posterior surgery, decreased with Vanc powder
Anterior or posterior approach preferred for OPLL?
Posterior. Anterior has a high risk of complications.
Guidelines for corpectomy
Okay for anterior alone at 1 level, should back up posterior with 2 levels, because higher risk for graft displacement and pseudoarthrosis
Why do you have to back up a 3 level ACDF?
Higher risk for pseudoarthrosis with isolated ACDF in 3 or more levels
Whats your diagnosis in this patient with visual disturbances and isolated RUE and LLE numbness?
MS. Note the focal demyelinating lesions without any adjacent cord compression. This is how you differentiate it from cervical meylopathy.
Football player has transient quadriplegia that resolves in minutes. What is the next step?
MRI. If he has stenosis then no return to play. If MRI is normal and he has no residual symptoms, he may return to play.
What is your diagnosis? What is the associated condition?
Basilar invagination, note the dens is now through the foramen magnum. This is associated with RA.
What’s your diagnosis? What’s the associated condition
Note the stair step deformity of multiple levels of cervical spondylosis seen in RA.
Measurements/lines seen in basilar invagination?
Ranawat C1-2 index: distance from C2 pedicle to line drawn from anterior to posterior arch. Abnormal < 13mm. MacGregor’s line: tip of dens to line from hard palate to most caudal portion of skull base, >4.5mm abnormal. Chamberlin’s line: tip of dens to line from hard palate to posterior edge of foramen magnum, >5mm abnormal
Operative management of basilar invagination
Occiput – C2 fusion with traction at time of surgery if able, anterior transoral decompression and posterior fusion if there is brain stem compression
Cervical spine measurements when assessing atlantoaxial instability
ADI > 3.5mm = instability, >7mm = disrupted alar ligaments, >10mm = surgery indicated. PADI <14mm = indication for surgery. >13mm greatest sign for recovery.
Operative management of rheumatoid C1-C2 instability
C1-2 fusion with wiring +halo, C-1 transarticular screw, C1-2 Harms or occipute to C2 fusion with posterior arch decompressiona and possible odontoidectomy
Indications for operative management in subaxial subluxation in RA
Neuro sx, >4mm spondylolisthesis or 20% displacement (higher likelihood for cord compression). Also cervical height/width ratio <2 is 100% specific for predicting neurologic compromise
Abatacept mechanism of action
MCH receptor antagonist
Operative management of subaxial subluxation in RA?
Same algorithm as cervical myelopathy
50% of cervical flexion/extension comes from what joint
Occiput-C1
50% of cervical rotation comes from what joint
C1-C2
Blood supply to cartilaginous disc?
No direct blood supply, comes through cartilagenous endplates.
C5 reflex
Biceps
C6 reflex
BR
C7 reflex
Triceps
L4 reflex
Patellar tendon
S1 reflex
Achilles
What defines instability on c-spine flex/ext views?
> 3.5mm translation and/or 11 degrees of angulation across any level
% of patients over 40 with asymptomatic herniated cervical disc
28%
Timing to operate on patients with cervical radiculopathy
Non-op management for at least 12 weeks. Only indication to treat early is with progressively worsening weakness.
Indications for isolated foraminotomy
No neck pain, radiculopathy with soft foraminal disc herniation, normal cervical lordosis
Indication for cervical disc replacement
No facet arthritis, young patient, single or two level disc disease or foramenal narrowing with radiculopathy or myelopathy, neck pain is a relative contraindication. Benefit is possible decrease in adjacent segment degeneration.
Palpable landmarks for C2 – C6
C2 = angle of mandible, C3 = hyoid, C4-5 = thyroid, C5-6 = cricoid cartilage 1st ring, C6 = carotid tubercle
What innervates the omohyoid?
Branches of the ansa cervicalis
Main structure at risk when placing screws into the occiput
Transverse foramen, screws shouldn’t be longer than 12mm
Strongest type of screw to place into C2
Pedicle > Translaminar >Pars
Management of post-op C5 palsy
Only observation. EMG, steroids, foramenotomy are all not indicated, 95% recover spontaneously.
Recurrent laryngeal nerve more commonly injured
No difference in sides. Left goes around aortic arch, right goes around the subclavian and is more superficial in the approach.
How does Horner’s syndrome occur during ACDF?
Failure to protect the sympathetic chain on the longus coli, highest risk level is C6
How does hypoglossal injury occur during ACDF? What are the clinical signs?
C2-3, C3-4 level approach puts the hypoglossal nerve at risk (CN XII). Tongue will deviate to the side of injury
Most common cause of post-op airway compromise
Hematoma
Mortality in patients with mediastinal perforation after ACDF
50%
Ways to limit post-op dysphagia after ACDF
Limit retraction, deflate/reinflate ET tube after retractors are placed, decrease surgical time, steroids, zero profile or no anterior plate
Rate of adjacent segment degeneration after ACDF
2.6% per year, 20% over 5-10 years
Risk factors for adjacent segment degeneration after ACDF?
Plate <5mm from adjacent level, smoking and female
% of spinal cord injuries associated with poor transfer techniques after injury
Up to 25%
What embryonic layer does the spinal cord develop from?
Ectoderm -> neural tube
What anomalies occur when the neural tube fails to close?
Proximally= anencephaly. Distallly = spina bifida.
What embryonic layer becomes the peripheral nervous system?
Neural crest
What embryonic layer becomes the vertebral bodies and discs?
Notocord, if this fails to form appropriately you can get hemivertebrae and bars.
Descending motor tracts
Lateral corticospinal tract (main voluntary motot, UE pathways are more central). Ventral corticospinal tract (volunatry motore)
Ascending sensory tracts
Dorsal column = deep touch, vibration and proprioceptions. Lateral spinothalamic tract = pain and temperature. Ventral spinothalamic tract = light touch.
Spinal cord blood supply
2/3 comes from the anterior spinal artery, injury results in deficits to the lateral corticospinal and ventral corticospinal tracts. 1/3 comes posterior.
Cord levels supplied by Artery of Adamkiewicz
In 75% the artery originates on the left from the posterior intercostal branch off the aorta and travels from T8-L1, supplying the lower 2/3 of the spinal cord.
Why increase MAPs when patients loose motor signals intra-op?
Most common reason is vasospasm of the anterior spinal artery, increasing the MAPs pushes the blood through the vasospasm
How do you define the level of injury in spinal cord injury?
Ensure the bulbocavernosus reflex is back indicating they are no longer in spinal shock. Then identify the most cephalad level with normal bilateral sensory and motor function
Vent dependent level in spinal cord injjry
C1-4
Vend independent but unable to feed self in spinal cord injury
C5
Able to feed self, manual wheelchair and drive car level in spinal cord injury
C6
Level of spinal cord injury that allows use of manual wheelchair and indepence with transfers
C7
Steroids in spinal cord injury
Not indicated
Algorithm for timing of operative management in spinal cord injury
Incomplete = surgery within 12 hours can save 1-2 functional levels. Complete = surgery within 24 hours. Central cord = typically nonop unless they have severe worsening of symptoms. GSW = typically non-op unless cord compression with incomplete SCI and fragment in canal.
Treatment in anterior spinal cord injury from vascular occlusion or ischemia?
No intervention, observation is all you can do
Incidence of depression in spinal cord injury
11%
Spinal cord level predisposed to autonomic dysreflexia
T6
Osteophytes in DISH vs AS
DISH = flowing, AS = marginal
What’s your diagnosis?
DISH, it is associated with massive amounts of right sided thoracic bone formation
Operative management of spinal fractures in DISH and AS?
Long instrumented fusions and epidural hematoma decompression
Imaging work up in trauma patients with DISH and AS
Need full spine CT to look for non-contiguous injury
How many ossification centers in C1?
3, lateral masses fuse at age 7
How many ossification centers in C2?
5, there is a subdental (basilar) synchondrosis that fuses between 5-7 and can become an os odontoideum if it doesn’t fuse.
Why are odontoid fractures prone to non-union?
There is a vascular watershed at the waist between the internal carotid and vertebral arteries.
Treatment algorithm of ondontoid fractures
Type I = tip = collar. Type II = waist, non-op if <50 and/or displaced <6mm and 10 degrees, op if >50 and displaced. Type III = body = collar.
Sports clearance in this patient?
Patients with an os odontoideum should not be cleared for contact sports
Risks for non-union in odontoid fractures
Age >5, displacement >6mm. posterior angulation >10 deg, diabetes, delay in treatment
Why not treat an odontoid fracture in a halo?
40% mortality in patients >65 due to pneumonia, cardiac and respiratory arrest
Indications for anterior odontoid screw
Type II fracture that is reduced in a patient with good bone, intact transverse ligament and no barrel chest
Types of C1 fractures
I = isolated arch, II = anterior and posterior arch, III = isolated lateral mass. Treatment depends on if the transverse ligament is intact.
Radiographic measurements that indicate an injury to the transverse ligament in C1 fractures
Sum of lateral mass displacement >8.1mm
ADI and PADI imaging thresholds for transverse ligament injury
ADI <3mm (<5mm kids), 3-5mm = transverse ligament injury with apical and alar intact, >5mm = apical, alar and transverse injured
Treatment algorithm for C1 fractures
Halo or collar if stable (<8.1mm lateral mass displacement on ondontoid view). Occiput -C2 fusion if unstable.
Most common fracture associated with facet dislocations
Superior facet
Spondylolisthesis seen in unilateral vs bilateral facet dislocation
Up to 25% if unilateral, 25-50% if bilateral
Indications for MRI in cervical facet dislocation? Treatment?
Altered mental status, failed closed reduction, neurologic before/deterioration during reduction = MRI. If not reduced, go posterior to reduce/stabilize. If reduced and needs discectomy, go from the front.
Injuries associated with vertebral artery injury
OCD, transverse foramen fracture, facet dislocation, basilar skull fracture
Powers ratio
CD/AB. Normal = 1, abnormal = OCD
Treatment of OCD fracture dislocation?
Occiput to cervical fusion
Management of bilateral C2 pars fractures
Look for other injuries in c-spine (30%). If <3mm displaced and intact disc with no angulation = collar. If 3-5mm displaced = halo, if >5mm displaced try to reduce w/traction, fi doesn’t reduce = C1-2 maybe 3 PSIF.
% of patients with non-continguous spine fracture in subaxial c-spine fractures
10-15%
Management of flexion vs extension tear drop.
Flexion tear drop is unstable, associated with SCI and needs anterior vs. ant/post surgery. The extension tear drop is an ALL ligament avulsion and can be treated in a collar (shown).
Management of floating lateral mass in subaxial c-spine injury
Needs posterior fusion if needs reduction, can do anterior if already reduced. No indication for non-op because it is unstable.
C-spine injuries that should not be treated in a halo
Age >50 and subaxial c-spine (bell-ringer phenomenon with increased subaxial motion, poorly controls lateral bending)
Contraindications to halo orthosis
Cranial fracture, infection, severe soft tissue injury, <2 years old, age >50, chest trauma, obesity
Adult halo pin technique
4 pins at 8in-lbs. Anterior pin is lateral 2/3’s of orbit and 1cm above supraorbital ridge below the equator. Posterior pin is 180 Degrees from the anterior pin and below the equator.
Pediatric halo pin technique
8 pins at 4 in-lbs
Complications associated with halos
Loosening (40%), infection (20%), supra orbital nerve palsy and abducens palsy (CN VI, shown)
What do SSEPs monitor
Dorsal sensory column. The UE or LE is stimulated and transcranial leads from the somatosensory cortex record a response.
SSEP or MEP less variable with anesthetic?
SSEP. Anesthetic gas can make MEPs less reliable
Cons of SSEPs
Not as reliable and slower to respond to injury. MEPs detect ischemic or other injury to the anterior cord.
SSEP alert levels? MEP alert levels?
50% decrease in amplitude and/or 10% decreased latency. >75% decrease in amplitude for MEPs.
What do MEPs monitor?
Lateral and ventral motor tracts. Transcranial stimulation of motor cortex, measures response in muscle contraction.
