Spine Flashcards
Is the inferior articular process of the facet joint anterior or posterior in the cervical spine?
Posterior
What is the orientation of the zygopophyseal joints of the cervical, thoracic and lumbar spine?
see image
What does a high riding vertebral artery refer to?
An abnormal course in C2
From what levels do the vertebral artery normally run?
C1-C6
In what percent of the population does the vertebral artery run in C7?
7.5% Normally runs from C1-C6
What is spinal shock?
All phenomena surrounding transaction of the spinal cord that results in temporary loss of all or most spinal reflex activity below the level of injury. Characterized by loss of bulbocavernosus reflex
What is neurogenic shock?
Hypotension and bradycardia following SCI
Which vertebrae have bifid spinous processes?
C2-C6
In what percent of people does the vertebral artery run in C7?
7.5% Remember - mostly it’s C1-C6
Describe the safe zone for 8mm occipital screws. What are the dangers?
+/-2cm at Nuchal line +/-1cm, 1cm below the nuchal line +/-0.5cm, 2cm below the nuchal line The dangers are: Dural venous sinuses that are immediately behind these regions
Describe the insertion point for thoracic pedicle screws:
Intersection point of 2 lines: A: Vertically along: Midpoint of facet joint and/or insertion of TP into the lamina (the Valley) B: Horizontally along: Superior ridge of TP and/or inferior base of facet joint
Describe the insertion point for lumbar pedicle screws
Intersection of 2 lines: A: Vertically along the superior facet B: Horizontally along the mid-point of the TP
What level has the smallest pedicle? The largest?
Smallest overall: T4 Smallest in L-spine: L1 Largest in T-spine: T1
Define the motor level
Most caudal level with 3/5 power with 5/5 power above
What is the grading system in the ASIA scale?
E: “Excellent.” No neurological compromise D: Incomplete: >50% muscles below level >/= 3/5 C: Incomplete: /= 3/5 B: Incomplete: only sensory preserved. Motor dysfunction includes sacral segments S4-5 A: “Awful”. Complete. No motor or sensory function is preserved, including sacral segments S4,5
Define the sensory level
Most caudal level with normal pinprick and light touch
What is the most common incomplete cord injury?
Central cord
With respect to central cord syndrome, what is the presentation, pathophysiology and prognosis?
Presentation: Motor deficit UE>LE, hands>arms Pathophysiology: Corticospinal tract, with part controlling hands centrally, are more affected Prognosis: Good. Full function rare but omst ambulatory
With respect to anterior cord syndrome, what is the presentation, pathophysiology and prognosis?
Presentation: Motor dysfunction LE>UE & dissociated sensory deficit below SCI with STT lost and dorsal columsn preserved
With respect to Brown-Sequard syndrome, what is the presentation, pathophysiology, prognosis?
Presentation: ipsilateral loss of motor function, proprioception and vibration with contralateral loss of pain and temperature Pathophysiology: Ipsilateral: Motor: LCST, Sensory: DC Contralateral: Sensory: LSTT Prognosis: Excellent 99% ambulatory
What is posterior cord syndrome?
Loss of proprioception only. Very rare
What tract is the main descending motor pathway in the cervical spinal cord?
Lateral corticospinal tract
The occiput is the thickest in what location?
5cm lateral to the external occipital protuberance
In the setting of bilateral C5-6 facet dislocation, which of the following structures is usually preserved? A: Facet joint capsules 2: Ligamentum flavum 3: Poseterior annulus 4: Anterior longitudinal ligament 5: Interspinous ligament
4: Anterior longitudinal ligament
Which of the following pedicles has the smallest transverse diameter in most people? A: T1 B: T12 C: L1 D: L3 E: S1
3: L1 Remember, T4 is the smallest overall, with L1 being the second smallest, but T4 is not listed in this question
Which area of the spinal cord has the worst collateral blood supply? The best?
Worst: T4-T9 Best: Cervical and lumbar - they have redundant supply
Describe the main blood supply to the spine? What is the name of the collateral blood supply?
Main: 1x median longitudinal anterior spinal artery 2x (right & left) longitudinal posterior spinal arteries These are supplied by various radicular arteries Collateral: Vaso Corona: anastomosis between the longitudinal vessels forming a fine pial plexus Gives limited blood supply
What artery provides the largest blood supply to the lumbar area? Where does it arise?
Artery of Adamkeiwicz. Arises most commonly from left T8-10
What is the Artery of Adamkeiwicz?
Major radicular artery supplying the longitudinal arteries in the T/L spine Usually arises from left T8-10 Can arise on right or left, anywhere from T7-L4 Usually Left T10
What are the signs of sacral dysmorphism? Why is it important and what should you do instead?
Signs: Sacralization of L5 Lumbarization of S1 Presence of mammillary processes Oval or oblong foramen Tongue in Groove sign of SI joint Important to recognize to avoid iatrogenic injury to L5 during SI screw insertion. If dysmorphic, plan for S2 screw instead (of S1)
What is the highest motor level that the patient can have and initially still be ventilator independent? Why?
C5 C3,4,5 make up the phrenic nerve, which supplies the motor function of the diaphragm (C3,4,5 keep the diaphragm alive) People with C3-C4 levels can progress to be ventilator independent
What are Harris’ measurements of the spine? What do they measure?
They measure atlanto-occipital dissociation There are 2 measurements: Basion to the tip of the dens (BDI) & Basion to the posterior axial line Neither one should be >12mm (Rule of 12’s)
What is the rule of 12’s in the spine?
Harris’s Rule of 12’s: Measures occipito-atlantal dissociation. On the Harris measurements, neither the BDI or BAI should be >12mm. If it is, it’s a sign of occipito-atlantal dissociation
What is a Jefferson’s fracture? mechanism?
Fracture of the lateral mass of C1 - essentially a “burst fracture” of c1 from axial loading - usually diving into a pool or similar mechanism
In a Jefferson’s fracture, how much lateral overhang on open mouth x-ray indicates disruption of the transverse ligament?
A total overhand (both sides added up) of >8mm indicates disruption of the transverse ligament (>6.9mm on CT, though there is some controversy)
What are the risk factors for non-union of odontoid fractures?
Displacement >6mm Angulation >10
What is a Hangman’s fracture? mechanism?
bilateral c2 pars fracture. hyperextension and distraction. traumatic spondylolisthesis of c2 on c3
What are the contents of the carotid sheath?
Common carotid artery +/- internal carotid artery Internal jugular vein Vagus nerve Deep cervical lymph nodes Artery is medial to vein, with nerve in between
Name the surface landmarks for the following spinal levels: C2-3 C3 C4-5 C6 C7 T4 T7 T8 L2 L4 L4-5 S1
C2-3: Mandible C3: Hyoid C4-5: Thyroid cartilage C6: Cricoid cartilage C7: Cervical vertebral prominence T4: Nipples T7: Distal scapular angle T8: Belly button L2: Renal arteries L4: Bifurcation of aorta L4-5: Iliac crest S1: Iliac bifurcation
What are the ligamentous attachments to the dens?
Transverse atlantal ligaments Alar ligaments x2 Apical odontoid ligament
Anterior atlantoaxial ligament
What is a PLIF? TLIF?
PLIF: Posterior lumbar interbody fusion TLIF: Transforaminal lumbar interbody fusion
What is autonomic dysreflexia?
Autonomic dysreflexia is a potentially dangerous clinical syndrome that develops in individuals with spinal cord injury at or above the level of T6, resulting in acute, uncontrolled hypertension.
Which of the following most accurately describes the medial-lateral (transverse) pedicle diameters in the T/L spine? 1. Diameters are smaller in the lower T-spine than mid-T spine 2. Diameters are smaller in the mid-T spine than high T-spine 3. Diameters are smaller in the high T-spine than the mid-T-spine 4. Diameters are larger in the upper L-spine than the lower T-spine 5. Diameters are larger in the high T-spine than the lower L-spine
- Diameters are smaller in the mid-T spine (T5-7) than the high T-spine (T2-T4)
A misplaced screw is recognized after lumbar surgery. The screw has grossly violated the inferior cortex of the left L4 pedicle. What is the most likely neurologic sequelae?
L4 weakness (ankle dorsiflexion)
Post-ACDF, a patient comes complaining of hoarseness. Which side did the patient likely have their surgery on and what structure was damaged?
Right side Damage to recurrent laryngeal nerve - Nerve is more variable on the right side so it’s easier to damage - So operate on the left if possible
A patient comes in post-cervical spine ACDF complaining of a drooping eyelid. On examination, you see that she has constricted pupils, no sweating on one side of the face (ptosis, miosis, anhidrosis). What structure was damaged. Where is this structure located?
Sympathetic ganglia in the C-spine was damaged - This caused a Horner’s syndrome The sympathetic ganglia are located on the longus colli muscles
What signs characterize UMN disorder?
Spasticity and exaggerated DTR
What levels do the vertebral artery run?
C1-C6
`What does a high-riding vertebral artery refer to?
The abnormal course in C2
In what percent of people does the vertebral artery run in C7?
7.5% - Remember it normally runs only from C1-C6
The occiput is thickest in what location?
5cm lateral to the external occipital protuberance
In the setting of bilateral C5-6 facet dislocation, which anatomical structure is usually preserved?
Anterior longitudinal ligament
Which area of the spinal cord has the worst collateral blood supply? The best?
Worst: T4-T9 Best: Cervical and lumbar - They have redundant blood supply
Describe the main blood supply to the spine? What is the name of the collateral blood supply
Main supply: 1 median longitudinal anterior spinal artery 2 (right & left) longitudinal posterior spinal arteries These are supplied by various radicular arteries Collateral: Vaso corona: anastomosis between the longitudinal vessels forming a fine pial plexus Gives limited blood supply
What is the artery of Adamkeiwicz?
Major radicular artery supplying the longitudinal arteries in the T/L spine Usually arises from left T10 - Arises Left 75% and right 25% Can arise on right or left anywhere from T7-4
What are the signs of sacral dysmorphism?
Sacralization of L5 Lumbarization of S1 Presence of mammillary processes Oval or oblong foramen Sacral intervertebral discs “Tongue in Groove” sign of SI joint Important to recognize to avoid iatrogenic injury to L5 during screw insertion - If dysmorphic, plan for S2 screw instead of S1
Why is it important to recognize sacral dysmorphism?
Important to recognize to avoid iatrogenic injury to L5 during screw insertion
What nerve is at risk with SI screw placement in a patient with sacral dysmorphism?
L5
What is the highest motor level that the patient can have and still be ventilator INDEPENDENT? Why?
C5 C3,4,5 make up the phrenic never, which supplies the motor function of the diaphragm - C3,4,5 keep the diaphragm alive
What are Harris’s measurements of the spine? What do they measure?
Measure occitio-atlanto dissociation 2 measurements: - Basion to the tip of the dens (BDI) and basion to the posterior axial line (BAI) - Neither one of these should be >12mm - This is the rule of 12’s
What is the rule of 12’s in the spine?
Measurements of occipito-atlantal dissociation - Neither one of the Harris measurements (BDI, BAI) should be greater than 12mm
What is a Jefferson’s fracture?
Fracture of the lateral mass of C1
In a Jefferson fracture, how much lateral overhang on open-mouth x-ray indicates disruption of the transverse ligament?
A total overhang (both sides added up) >8mm indicates disruption of the transverse ligament - >6.9mm on CT - there is some controversy
What are the risk factors for non-union of odontoid fractures?
Displacement >6mm Angulation >10deg
What is a teardrop fracture?
Fracture of the anterior inferior endplate - Must differentiate between flexion and extension types - Flexion is unstable and associated with SCI. Extension is stable
What are the contents of the carotid sheath?
4 things: Common carotid artery +/- internal carotid artery Internal jugular vein Vagus nerve Deep cervical lymph nodes - Artery is medial to the vein, with nerve in between
Neurogenic shock is best characterized by:
Systemic hypotension & bradycardia following SCI - Remember: neurogenic shock not equal to spinal shock
What is the expected functional outcome of a patient with a C5 neurologic level following complete SCI?
Mobility in an electric wheelchair - Cannot use UE
What is spinal shock?
Physiologic or anatomci transection of the cord, resulting in temporary loss or depression of all or most spinal reflex activity below the level of the injury - Characterized by loss of bulbocavernosus reflex - Important b/c exam is not reliable during period of spinal shock
Defined as temporary loss of spinal cord function and reflex activity below the level of a spinal cord injury.
characterized by
flaccid areflexic paralysis
bradycardia & hypotension (due to loss of sympathetic tone)
absent bulbocavernosus reflex
How do you perform a bulbocavernosus reflex?
Normal: - Anal sphincter contraction (anal wink) after squeezing the glans penis or tugging on the foley - In women, squeeze the clitoris or tug on the foley
Is the inferior articular process of the facet joint anterior/posterior vs. superior/inferior in the C-spine?
Inferior articular process is anterior
Name the intrinsic craniocervical ligaments
They all reside within the spinal canal. From dorsal to ventral: Tectorial membrane: connects posterior body of axis to anterior foramen magnum. Is the cephalad continuation of the PLL Cruciate ligaments: lies anterior to tectorial membrane, behind the odontoid process Odontoid ligaments (alar and apical)
What is the tectorial membrane a continuation of?
Posterior longitudinal ligament
Name the extrinsic ligaments of the craniocervical spine
Ligamentum nuchae: extends from external occipital protuberance to the posterior aspect of the atlas and cervical spinous processes Fibroelastic membranes: Replace the anterior longitudinal ligament, intervertebral disks, and ligamentum flavum between the occiput and atlas and between the atlas and axis Atlanto-occipital joint capsule Atlanto-axial joint capsule
What is the amount of lateral mass displacement necessary to indicate disruption of the transverse ligament on on imaging?
6.9mm vs. 8.1mm 6.9mm: Spence: critical amount of total displacement (on CT) 8.1mm: Heller. However this measurement may be obviated using calibrated axial and sagittal CT
What is Swischuk’s Line?
Connects the anterior aspect of the spinous processes of C1 and C3.
If the anterior aspect of the spinous process of C2 misses this line by ⩾2 mm true subluxation of hangman’s fracture must be considered.
This line is only applicable to those demonstrating subluxation.
The distance is frequently 2 mm or more if no subluxation is apparent.
Figure: (A) No subluxation. Therefore, PCL cannot be applied. Anterior aspect of spinous process of C2 commonly misses PCL by 2 mm. (B) Subluxation is present. The anterior aspect of spinous process of C2 misses the PCL >2 mm. Finding is suggestive of a hangman’s fracture of the neural arches of C2. (C) Pseudosubluxation is present. The anterior aspect of spinous process of C2 touches or lies within 2 mm of PCL. (Adapted from figure from Fesmire FM and Luten RC.16)
Describe the cervicomedullary angle and its significance:
The cervicomedullary angle can be measured on MRI by drawing a line along the anterior aspect of the cervical spinal cord and the medulla.
This angle is normally between 135° and 175°
With progressive craniocervical disease, the brainstem angulates ventrally over the displaced odontoid process, leading to increased obliquity of the cervicomedullary angle.
What are the synovial joints of the spine?
Facet joints
Atlanto-occipital joint
Lateral Atlanto-axial joint
Central atlanto-axial joint
Figures 8a and 8b show the radiograph and MRI scan of a 31-year-old man with severe back pain and intermittent leg pain. Which of the following anatomic measurements has been best correlated with this patient’s condition?
- Pelvic tilt
- Pelvic Incidence
- Lumbar Lordosis
- Thoracic Kyphosis
- C7 Sagittal plumb line
2.Pelvic Incidence
Which of the following is most predictive of disability in adult patients with scoliosis?
- Coronal plane cobb angle
- Retrolisthesis at L3/4
- Osteoporosis
- Sagittal plane decompensation
- Severity and number of levels of disk degeneration
- Sagittal plane decompensation
On a standing lateral radiograph of the spine in which the edge of the film represents a true vertical, a normal C7 plumb line should intersect which of the following anatomic landmarks?
- Center of the C7 vertebral body and posterior-superior corner S1
- Center of C7 body and anterior-superior corner of S1
- Anterior border of C7 vertebral body and anterior-superior corner of S1
- Anterior border of C7 body and posterior-superior corner of S1
- Posterior border of C7 vertebral body and posterior-superior corner of S1
1.Center of the C7 vertebral body and posterior-superior corner S1
Figure 169a is the lateral radiograph of a 19-year-old female gymnast with low back and leg pain. Examination reveals exacerbation of back pain with extension. She has a normal motor examination but diminished light touch sensation in an L5 distribution. What measurement shown in Figure 169b has been correlated with this disease?
- Slip Angle
- Sacral Slope
- Pelvic Tilt
- Pelvic Incidence
- Spinopelvic Angle
- Pelvic incidence
Figure 255 shows the axial CT scan of a 33-year-old man with severe neck pain after a motor vehicle collision. Which structure is most important in guiding treatment?
- VA
- Alar Lig
- Apical Lig
- Transverse Lig
- Post Lig Complex
- Transverse ligament
What osseous structure is seen by the * in Figure 237?
1- Inferior articular facet of C4
2- Inferior articular facet of C5
3- Superior articular facet of C5
4- Pedicle of C5
5- Pars interarticularis of C5
- Inferior articular process of C4
Figures 89a and 89b are the parasagittal and axial CT scans of a 42-year-old patient seen after a motor vehicle collison. What anatomic structure is identified by the asterisk in Figure 89b?
- C6 facet
- C7 facet
- C6 pars
- C6 pedicle
- C7 pedicle
- C6 Facet
What is the nerve injury shown?
CN VI
No lateral gaze
A 27-year-old male is an unrestrained passenger in a motor vehicle accident. He was medically stabilized in the emergency room. His initial injury CT scans are seen in Figures A and B. He is neurologically intact and placed in a halo fixator prior to surgical treatment. What is the most common neurologic complication with halo traction?
- Weakness in biting and chewing strength
- Deficit in medial and downward eye movement
- Deficit in lateral eye movement
- Inability to close eyes against resistance
- Tongue deviation toward the affected side
- Deficit in lateral eye movement (CN VI injury)
After application of a halo device, a patient has pain and numbness over the medial one third of the eyebrow. This is most likely the result of injury to which of the following structures?
- Second dorsal rami
- Facial nerve
- Auriculo temporal nerve
- Lesser occipital nerve
- Supraorbital nerve
- supraorbital nerve injury
The halo vest is least effective at controlling which of the following spinal motions? 1- Lateral bend 2- Flexion 3- Extension 4- Axial rotation 5- Axial distraction
- Axial distraction
What vertebra does the vertebral artery run in?
C1-C6
Although all the cervical vertebra have a vertebral foramen
Which vertebra has the smallest diameter pedicle in the lumbar spine? Smallest overall?
L1 is smallest in lumbar spine T4 is smallest overall
Which vertebra has the largest pedicle in the upper spine? Overall?
T1 largest in upper spine L5 largest overall (unless you count S1, then it’s S1)
The occiput is thickest in what location? 1.At the external occipital protuberance 2.1cm lateral to the foramen magnum 3.2cm superior to the foramen magnum 4.2cm cranial to the occipital condyles 5.5cm lateral to the external occipital protuberance
- 5cm lateral to the external occipital protuberane
A misplaced pedicle screw is recognized after lumbar surgery. The screw has grossly violated the inferior cortex of the left L4 pedicle. What is the most likely neurologic sequelae? 1. Weakness of plantar flexion, numbness along the lateral foot 3. Weakness of hip flexion, numbness along the inguinal crease 4. Weakness of foot dorsiflexion, numbness along the medial ankle 5. Weakness of toe dorsiflexion, numbness of the first web space
4: Weakness in foot dorsiflexion, numbness along medial ankle Knocked out L4
Which of the following most accurately describes the medial-lateral (transverse) pedicle diameters in the thoracic and lumbar spine? 1. Diameters are smaller in the lower thoracic spine (T10-T12) than the mid-thoracic spine (T5-T7) 2. Diameters are smaller in the mid-thoracic spine (T5-T7) than the high thoracic spine (T2-T4) 3. Diameters are smaller in the high thoracic spine (T2-4) than the mid-thoracic spine (T5-T7) 4. Diameters are larger in the upper lumbar spine (L1-2) than the lower thoracic spine (T10-12) 5.Diameters are larger in the high thoracic spine (T2-T4) than the lower lumbar spine (L3-S1)
- Diameters are smaller in the mid-thoracic spine (T5-T7) than the high thoracic spine (T2-T4)
A 76-year-old woman has neck pain after falling down a flight of stairs. Figures 65a and 65b show a lateral radiograph and sagittal CT scan of her cervical spine. Which factor is an absolute contraindication for the placement of C1-C2 transarticular screws? -Osteoporosis
- Aberrant Vertebral Artery
- Previous C2 laminectomy
- C1 fracture
- Disruption transverse lig
- Aberrant vertebral artery ??
What is autonomic dysreflexia?
In a high-level spinal cord injury, intact lower motor neurons sense the painful stimuli below the level of injury and transmit the message up the spinal cord (see diagram). At the level of the spinal cord injury, the pain signal is interrupted and prevented from being transmitted to the cerebral cortex. The site of the spinal cord injury also interrupts the two branches of the autonomic nervous system and disconnects the feedback loop, causing the two branches to function independently. The ascending information reaches the major splanchnic sympathetic outflow (T5-T6) and stimulates a sympathetic response. The sympathetic response causes vasoconstriction, resulting in: hypertension pounding headache visual changes anxiety pallor goose bumps below the level of injury This hypertension stimulates the baroreceptors in the carotid sinuses and aortic arch. The PSNS is unable to counteract these effects through the injured spinal cord, however. Instead, the PSNS attempts to maintain homeostasis by slowing down the heart rate. The brainstem stimulates the heart, through the vagus nerve, causing bradycardia and vasodilation above the level of injury. The PSNS impulses are unable to descend past the lesion, and therefore no changes occur below the level of injury.
What is autonomic dysreflexia, and how do you manage?
potentially fatal
presents with headache, agitation, hypertension
caused by unchecked visceral stimulation
check foley
disimpact patient
Autonomic dysreflexia is defined as “an increase in systolic blood pressure of at least 20% associated with a change in heart rate and accompanied by at least one of the following signs (sweating, piloerection, facial flushing), or symptoms (headache, blurred vision, stuffy nose)” due to a stimulus such as overdistended bladder or bowel impaction. Guidelines for treatment of autonomic dysreflexia include 1) patient immediately placed in a sitting position if the person is supine. 2) clothing or constrictive devices need to be loosened 3) troubleshoot etiologies for bladder distention or bowel impaction 4) a SBP >150 mmHg may need to be treated with nifedipine or nitrates 5) close monitoring of symptoms, blood pressure, and heart rate for at least 2 hours.
