Spine Flashcards
Describe the imaging findings in this patient with progressive lower limb weakness
The MRI reveals a mass lesion below the conus medullaris that may be associated with either the filum terminale or a cauda equina nerve root. The lesion enhances homogeneously with contrast administration and the differential diagnosis includes a myxopapillary ependymoma, peripheral nerve sheath tumour such as a schwannoma or neurofibroma and meningioma.
During a lateral extracavitatory approach for a thoracic discectomy, which rib head is removed?
The T10 rib head overlies the T9/10 disc space. The T10 rib articulates with the demifacets on the T9 and T10 vertebral bodies and the rib tubercle articulates with the superior part of the T10 transverse process.
How are C1 and C2 combine fractures managed?
Based on the C2 fracture - most common combination is a C1 fracture with a C2 type 2 peg fracture
How are fractures of the C1 classified?
Jefferson’s (after Sir Geoffery Jefferson of QS)
1 - posterior arch
2 - anterior arch
3 - Anterior and posterior arches (burst)
4 - Lateral mass fracture
**Alternatively the Landell’s classification is also used**
How are Jefferson’s fractures managed?
Type 1/2 are isolated anterior or posterior arch fractures: managed in a hard collar or halo for 8-12 weeks
Type 3 are burst fractures: if transverse ligament intact then collar, if disrupted then halo or surgeyr
Type 4 are unilateral lateral mass fractures: hard collar for 8-12 weeks
How are occipital condyle fractures classified?
Anderson Montesano classification into 3 types:
1 - Comminuted fracture of the occipital condyle
2 - Linear basal fracture extending into the occipital condyle
3 - Avulsion fracture of the occipital condyle (at the alar ligament attachment)
How are scoliosis corrections approached?
<90 deg with posterior spinal instrumentation and fixation
>90 deg need combined anterior and posterior approaches
How can the integrity of the transverse ligament be identified?
- Rule of Spence (sum of the overlap of the C1 arches >6.9 mm on open mouth Xray although 8.1 mm with magnification correction)
- ADI >3 mm
- High STIR signal on MRI
How do you apply traction with Gardener Wells tongs?
Administer analgesis and muscle relaxants.
Pin placement 1 cm above the pinna inline with the EAM (anterior if you want ext and posterior if you want flex)
Tighten tongs to 31lbs of force (indicator becomes 1 mm proud)
Initial weight of 10lbs and then 10lb increments every 20 minutes until a max of 5lb per level. After 35lb repeat a cervical x-ray before adding more.
How do you assess basilar invagination?
- Wackenheims clival line
- Chamberlain line - middle of hard palate to middle of opisthion
- McRae line - Basion to opisthion
- McGregor line - Middle of hard palate to bottom of opisthion
- Height index of Klaus - distance from tip of peg to line through the dorsum sella
How do you classify idiopathic scoliosis by age?
<3 = infantile; 3-10 = juvenile; >10 = adolescent
OR
early onset <5 and late onset >5
How do you clear the spine in an obtunded patient?
Whole spine CT is usually sufficient.
An MRI scan should be performed if there is a high index of suspicion
How do you grade skeletal maturity?
Risser grading
How do you manage a cervical burst fracture?
Corpectomy and plating.
A posterior fixation may be needed if posterior lig complex involved.
How do you manage a cervical VB compression fracture?
If <25 deg loss of height - conservative with collar 6-12 weeks
If >25 deg loss of height - surgical stabilisation
How do you manage a flexion tear drop fracture?
ACDF +/- corpectomy as this mechanism involves disruption of the disc
How do you manage a Scheuermann’s kyphosis?
Brace = <75 deg and skeletal immaturity
Surgery = failure of bracing or >80 deg and skeletally mature; posterior fusion with excision of the ligamentum flavum at the apex should be performed to prevent neurological deficit due to buckling.
How do you manage a trauma patient with normal C-spine CT but on-going pain?
MRI +/- flexion-extension xrays
How do you manage adolescent idiopathic scoliosis?
Observation with orthosis to identify and document curve progression.
Surgical intervention based on natural history of the curve, cobb angle and skeletal maturity i.e.
Curve <20 deg = observation
20-40 deg = brace if skeletally immature
>40 deg = brace if skeletally immature; surgery if skeletally mature or fail bracing.
How do you manage an isolated C2 extension tear drop fracture?
Hard collar 8-12 weeks
How do you manage facet dislocations?
Closed reduction and then posterior decompression and fusion
If unable to reduce then open posteriorly, drill off facets and fix. Then flip and do A.CDF.
How do you measure ADI and PADI?
ADI is between anterior peg and back of C1 anterior arch
PADI is between the back of the peg and the from on the C1 posterior arch
How do you measure coronal balance?
A vertical line from the centre of C7 should pass within 2 cm of the centre of the S1 VB (center sacral vertebral line)
How do you measure the clival angle?
Between Wackenheim’s line and the anterior skull base. If angle >143 deg then = platybasia
How do you measure the cobb angle?
Measured between vertebral that are maximally tilted. It is measured as the angle between the superior endplate of the proximal and inferior endplate of the distal vertebra. The apex of the curve is the most lateral vertebra
How do you treat occipital condyle fractures?
Non-rigid immobilisation for all types of fracture.
Rigid immobilisation with halo should be considered if bilateral or displacement >2 mm
OC fusion should be performed if there is overt instability (based on ligamentous disruption on MRI), neural compression from a displaced fragment or other associated unstable injuries
How does a syrinx present clinically?
Suspended sensory level in a cape-like distribution with dissociation of pain and fine touch; motor impairment affects the UL>LL and distal>proximal. There is sacral sparing and can result in a Horner’s syndrome.
How does age at diagnosis impact scoliosis management?
The earlier the age of diagnosis the more likely the deformity is to progress and need treatment
How does an anterior cord syndrome present?
Paralysis, autonomic dysfunction and loss of pain but intact sensation - anterior spinal artery infarct occurs post AAA repair.
How does os odontoideum present?
- Occipital pain
- Myelopathy
- Intracranial symptoms from vertebrobasilar ischaemia
How does the rib articulate with the vertebra?
The 5th rib covers the T4/5 disc space and articulates with the tubercle on the TP of the 5th rib;
How far lateral is the V3 segment from the middle of C1?
14 mm
How is basilar invagination in RA (Cranial settling) treated surgically?
O-C2 fixation
How is os odontoideum managed?
Surveillance or surgery based on the degree of instability, neurological deficit or risk of future spinal cord injury.
C1/2 fixation is often recommended due to the risk of SCI with minor trauma.
Reduction is attempted. If irreducible then decompression with fusion is required.
PEG screws should NOT be used
How is the L5/S1 facet orientation different from the rest of the lumbar spine?
The lumbar spine has sagittally orientated facets. The L5/S1 has more coronally orientated facets to allow rotation
How is the optimal CPP calculated?
Measuring the PRx at a variety of different CPPs. The CPP with a 0 PRx is optimal.
How is the Stable vertebra defined in scoliosis?
The vertebra bisected by the centre sacral line
How long should you given LMWH prophylaxis for following SCI?
3 months
How should a neuromuscular scoliosis be managed?
MDT assessment of the spinal deformity and the underlying neuromuscular disease:
Observation if curve <30 deg
Spinal orthosis does not prevent curve progression but slows the progression.
Surgery is offered when the curve >40 deg, with earlier surgery in Duschenne’s MD (>20 deg).
Surgery should not be delayed until skeletal maturity.
How should AOD be treated?
OC fusion
How should occipital condyle fractures be imaged?
Fine cut CT of the CC junction
MRI for ligamentous injury
How should you manage patients with complete SCI (ASIA A) with unstable spines?
Internal fixation to allow early mobilisation and rehabilitation. Improves ability to care for patients and reduces risk of secondary complications (LRTI / DVT etc)
How would you manage this patient?
This imaging reveals an intradural extramedullary lesion. The patient should undergo intradural resection of the lesion under neurophysiological monitoring. It is important to completely expose the tumour to identify the proximal and distal connections. I would aim to perform an L1-3 laminoplasty followed by midline durotomy. I would aim to identify the structure it arises from. If arising from the filum terminale it likely represents a myxopapillary ependymoma and should be resected en-bloc without violation of the capsule to prevent a recurrence. If the lesion arises from a nerve root this likely represents a peripheral nerve sheath tumour and the root should be tested using neurophysiological monitoring. It is most likely to be a sensory nerve root which can be sacrificed.
In this case, you find the tumour is stuck to the conus without a clear cleavage plane. How do you proceed?
This most likely represents a filum terminal myxopapillary ependymoma. The aim of surgery would be an en-bloc resection without violation of the capsule, which would be curative. If a plane cannot be safely generated between the conus and the tumour capsule then a portion of the capsule should be left to prevent a permanent deficit and potentially treated with post-radiotherapy.
In trauma, when is it safe to not place a collar?
When the patient is alert, non-intoxicated and without a distracting injury where there is no neck pain and no neurology
In which group of Hangmann’s fractures should traction be avoided?
Type 2a as the C2/3 disc space is ruptured
Is an MRI needed prior to closed reduction of a fracture-dislocation?
No, traction reduction is safe in an awake patient. Failure to reduce with traction or low GCS due to head injury/intoxication should undergo MRI.
Label the spinal tracts
Answers
Name all the labels
With labels
Name all the labels.
Note the dorsal root is proximal to the DRG and the dorsal ramus is distal!
Regarding Type 2 peg fractures, which approach has a higher fusion rate?
Posterior > Anterior
(Anterior allows preservation of rotation but fracture line has to be perpendicular to screw trajectory and body habitus satisfactory)
Should bracing be used for congenital scoliosis?
NO!
What % of patients have a vertebral artery injury following C-spine trauma?
10%
What age does neuromuscular scoliosis develop?
<10 years of age and more likely to progress therefore compared to an idiopathic adolescent scoliosis
What anatomical factors prevent C2 peg screw placement?
Patient factors: Barrel chest, thoracic kyphosis and short neck
Fracture type: Oblique fracture in direction of the screw
Bone quality: osteoporosis
What are the attachments of the ALL?
From the anterior body of C2 to the sacrum binding the vertebral bodies and discs
What are the attachments of the PLL?
From the posterior body of C2 to the sacrum binding the vertebral bodies and discs
What are the BAI and BDI?
BAI = basion-axial interval and is measured by the distance between a straight line drawn up the back of C2 and the basion. If >12mm then suggests atlanto-occipital dislocation.
BDI = basion dental interval measured between the basion and tip of the peg. <12 mm on Xray and <8.5 mm on CT is normal.
What are the bail out options for a C2 pedicle screw?
- C2 pars screw
- Lamina screw
- OC-fusion
What are the branches of the V4 segment?
PICA and spinal arteries
What are the canadian C-spine rules?
Imaging is needed in any patient:
>65 years, dangerous mechanism or paraesthesia in the extremities.
Low risk factors are simple mechanism, ambulant after injury, delayed onset of neck pain with normal ROM and no paraesthesias
What are the causes of a neuromuscular scoliosis?
Muscular causes are muscular dystrophies such as Duschenne, myotonic dystrophy and congenital myotonia
Neurological causes are UMN = cerebral palsy, friedrich’s ataxa, syringomyelia and spinal cord injury <10 years of age; LMN = Spinal muscular atrophy and polio
What are the causes of congenital scoliosis?
Type 1 = Defects of formation = hemivertebrae, spina bifida and wedge
Type 2 = Defects of segmentation = block, unilateral bar, unilateral bar + hemivertebra
Type 3 = mixture of the above
What are the causes of hypotension following SCI?
- Trauma related (bleeding etc)
- Neurogenic shock
Keep the MAP 85-90 mmHg for the first 7 days!
What are the classical features of neuromuscular scoliosis?
Long sweeping C-shaped curves that extend to the pelvis. Most commonly occur in the thoracolumbar or lumbar spine
What are the clinical features of a syrinx associated scoliosis?
Rapidly progressive, left sided and associated with abnormal abdominal reflexes
What are the common causes of a positive Rhomberg’s test?
Loss of the dorsal columns secondary to Vit B12, neurosyphilis, sensory neuropathy e.g. CIDP, Friedreich’s ataxia and Meniere’s disease (loss of vestibular function)
What are the contraindications to bracing for adolescent scoliosis?
Skeletally maturity
>40 deg curve
Thoracic lordosis
What are the different types of adult scoliosis?
Type 1 = Adult degenerative
Type 2 = Idiopathic adolescent that progresses in adulthood
Type 3 = Secondary adult due to leg length discrepancy, hip pathology or metabolic bone diseases
What are the facet joint orientations in the subaxial spine?
45 deg sagittal
0 deg coronal
This allows flexion and extension (greatest at C5/6 and C6/7)
What are the features of infantile idiopathic scoliosis?
Male > female, left thoracic curve with plagiocephaly, developmental delay, congenital heart disease and developmental hip dysplasia
What are the imaging features of AOD?
Craniocervical SAH
Large prevertebral haematoma
Power’s ratio >1
BAI or BDI >12
Condyle-C1 interval >2 mm = atlanto-occipital interval (highest sensitivity in paediatric AOD)
What are the main features of adolescent idiopathic scoliosis?
Females > Males
Right > Left thoracic curves
No severe pain
Risk factors for progression are the skeletal maturity (Risser stage)
Curves 50-75 deg at skeletal maturity progress by 1 deg per year
Lumbar curves are more likely to progress than thoracic as they lack the stability provided by the rib cage
What are the management options for scoliosis prior to bone maturity?
Fusion is avoided to prevent restriction of the thoracic cage and lung development. Surgical options include the use of an expandable prosthetic titanium rib and posterior instrumentation with growing rods.
What are the NEXUS criteria?
Defines whether cervical spine imaging is required in trauma:
Absence of midline cervical tenderness with no neurological injury in an alert patient with no distracting injury or intoxication does not require c-spine imaging.
What are the two types of anterior cervical plates?
Static and dynamic.
With static plates, they are rigidly locked to the plate. Dynamic plates allow some movement between the plate and screw to facilitate load sharing.
What are the two types of basilar invagination?
Group A - both chamberlain’s lines and McRae’s lines are crossed.
Group B - Chamberlain but not McRae’s line is crossed.
Group B occurs when the clivus is abnormal and the Clival angle is low and there is basilar impression.
What are the two types of os odontoideum?
Orthotopic and dystopic
What are the types of Scheuerman kyphosis?
Type 1 = thoracic
Type 2 = thoracolumbar (more painful)
What BDI is associated with atlanto-occipital dislocation?
>10 mm
What brace should be used for idiopathic adolescent scoliosis?
If above T8 then CTLS (Milwaukee brace)
If lower than T8 then TLSO
What do non-decussating CST fibres do?
15%, these form the anterior CST and supply proximal muscles of the upper limb
What do side bending xrays tell you about scoliosis?
If the curve corrects then it is nonstructural; if it persists then it is structural
What do the different spinocerebellar tracts do?
Dorsal and ventral spinocerebellar tracts coordinate lower limb movement whilst the rostral spinocerebellar tract controls head and upper limb movement.
What does the lateral border of the pars align with?
The medial border of the pedicle
What factors are suggestive of non-union for peg fractures?
>5 mm displacement
Age >50
Comminuted fractures
Delay in treatment
What happens to the pedicle orientations in the lumbar spine?
Become more medially orientated from L1-L5
What happens to the vertebral body and ribs at the apex of a scoliosis?
The spinous process is pushed towards the concave side making the lamina narrower on that side. The VB is distorted to the convex side. the rib cage is narrowed on the convex side as the rib is pushed posteriorly.
What imaging is required in the investigation of a scoliosis?
MRI brain and spine to look for syrinx, chiari and tethered cord
What is a dystopic os odontoideum?
Where the os is fused to the basion so does not move with the C1 arch on flexion-extension views
What is a neutral vertebra in scoliosis?
The first non-rotated vertebral at the cranial and caudal ends of the curve.
What is a normal ADI?
<3mm in adults
<5 mm in paeds
What is a normal PADI?
>13 mm
What is a posticulus posticus?
Calcification of the oblique atlanto-occipital ligaments forming a bony bridge over the V3 segment of VA. This may mislead the surgeon when placing a C1 lateral mass screw and increase the risk of a VA injury
What is a tear drop fracture?
Flexion tear drop occurs at C4-6 and represent significant ligamentous injury with posterior displacement of the VB compared to the VB below.
Extension tear drop is less severe are represents disruption of the ALL.
What is an arcuate foramen?
Ponticulus posticus
What is an orthotopic os odontoideum?
Orthotopic is connected to the anterior arch of C1 so moves with it on cervical flexion-extension views
What is AOD more common in children?
Occipital condyles are smaller and flatter
What is Brown-Sequard syndrome?
Hemisection of the cord causing ipsilateral motor and sensory loss with contralateral pain loss. Think MS, tumour or trauma
What is cranial settling?
Basilar invagination due to RA
What is dynamic stabilisation?
Connecting pedicle screws with rods so that motion is constrained but not eliminated. This causes less strain on the adjacent vertebra and therefore less adjacent segment disease.
What is power’s ratio?
A measure of atlantooccipital instability
From posterior arch C1 to basion divided by anterior arch C1 to opisthion
What is Scheuermann’s kyphosis?
Kyphosis >45 deg with >5 deg wedging across 3 vertebrae
Commonest cause of thoracic back pain in children and adolescents
Cause is unknown but may be related to avascular necrosis of the vertebral body apophysis
This is not corrected by active extension
What is the action of the lateral (medullary) reticulospinal tract?
Acts on the flexors of the trunk and inhibits the extensors (similar to the rubrospinal tract)
What is the action of the medial reticulospinal tract?
Controls the extensors of the trunk (and inhibits the flexors) - this is the opposite to the rubrospinal tract
What is the advantage of placing a plate in the cervical spine?
Prevents implant subsidence, minimised collapse / kyphosis, improved fusion rates, no need for external immobilisation
What is the AO classification for thoracolumbar fractures?
A = Compression (1 = wedge, 2 = split and 3/4 = burst);
B = Distraction (1 = bony chance throughout, 2 = posterior lig complex rupture, 3 = rupture through the disc space);
C = Rotation (1 = rotation-compression, 2 = rotation-distraction, 3 = rotation-shear)
**Note in B there is failure of the anterior and/or posterior tension bands
What is the ASIA scale?
A = No sacral sparing
B = Sensory but not motor and includes sacral sparing
C = Motor preserved but more than half of the myotomes are <3 power
D = Motor preserved but more than half the myotomes are >3 power
E = Normal examination
What is the C7 plumb line?
Measures sagittal balance. A vertical line from the centre of C7 should lie within 2 cm of the back corner of the S1 VB
What is the classification for AOD?
Traynellis classification:
1 - Anterior displacement of occiput (Powers ratio >1)
2 - Distraction (BAI and occipitocervical distance increased)
3 - Posterior displacement of occiput
What is the classification system for Peg fractures?
Anderson D’Alonso
What is the course of the dorsal and ventral spinocerebellar tracts?
Dorsal = Clarke’s column > Inf cerebellar peduncle > vermis
Anterior = Lamina V-VII > contralateral Sup cerebellar peduncle > ipsilateral vermis (crosses over and then crosses back again)
What is the course of the dorsal spinocerebellar tract?
Clarke’s column > inferior cerebellar peduncle > vermis
What is the definition of a high riding vertebral artery at C2?
Isthmus height < 5mm
What is the definition of a scoliosis?
Cobb angle >10 degrees in the coronal plane
What is the definition of idiopathic scoliosis?
Spinal deformity characterised by lateral bending and fixed rotation of the spine in the absence of a known cause
What is the definition of stability?
According to Punjabi and White, this is the “loss of the ability of the spine under physiological loads to maintain relationships between the vertebrae to prevent pain, deformity or neurological injury”
What is the difference between a C2 pars and a C2 pedicle screw?
The C2 pars screw is shorter, stopping before the foramen transversarium and is unicortical.
The C2 pedicle screw is longer and bicortical.
What is the difference between a structural and non-structural curve?
Structural curves do no correct with bending to <25 deg i.e. correction from 70 deg to 40 deg
What is the difference between basilar invagination and basilar impression?
Basilar invagination is when C2 projects above the foramen magnum
Basilar impression is where the upward displacement is due to acquired softening of the bones at the base of the skull
What is the differences morphologically between a neuromuscular and idiopathic scoliosis?
Neuromuscular curves tend to be longer and involve more vertebrae that an idiopathic scoliosis
What is the differential diagnosis of a Jefferson fracture in a child?
Pseudo-spread of the atlas (due to physiological growing of C1>C2)
Normal synchondroses (there are 3 ossification centres - one in the body and one in each arch). The posterior synchondrosis (in the spinous process) fuses by age 3 years whilst the neurocentral synchondrosis (between the arches and the body) fuse by age 7 years.
What is the effect of inotropes on ISP and SCPP?
Increases ISP and MAP with a resulting increase in SCPP
What is the Effendi classification for Hangman’s fractures?
1 - Fracture through the pars <3 mm displacement
2 - Fracture through the pars with >3 mm displacement and rupture of the C2/3 disc
(Levine–Edwards) 2a - Very severe angulation of the C2 body (>11 deg)
3 - Locked facets at C2/3
What is the entry point for a C2 pedicle screw?
A verticle line through the C2 pars bisecting a horizontal line through the C2 lamina. This lies in the superior medial quadrant. The screw is angled 20 deg medial and superior angulation is parallel to the C2 pars on lateral fluoroscopy.
What is the entry point for a thoracic pedicle screw?
Junction of the facet joint and the TP. Entry is in the upper 1/3 of the TP at its base
What is the function of the cuneocerebellar tract?
Coordination of the movement of the upper limb
What is the function of the dorsal spinocerebellar tract?
Posture and coordination of the lower limb movements
What is the Heuter-Volmann principle?
Increased loading across an endplate accelerated growth, whilst decreased loading inhibits growth. Imbalance of forces due to neuromuscular diseases leads to scoliosis.
What is the Lenke classification for idiopathic scoliosis?
Based on AP, lateral and side-bending radiographs.
The Cobb angle for all the curves are measured and then whether they are structural or not.
There are 6 different curve combinations
There are also lumbar and T5-12 sagittal alignment modifiers
What is the main morbidity of an early onset progressive scoliosis?
Cor pulmonale, right heart failure and premature death
What is the management for Hangman’s fractures?
Type 1 and 2 - conservative with reduction and Halo provides healing rates >90%
Type 2a / 3 - do not apply traction! Healing rates are 30% with Halo so can be tried first but if fail then need surgery for chronic instability. Surgery is ORIF and posterior fixation C1-3 or C2-3.
Ref: Effendi 1981 - management of 131 patients
What is the management of a chronic type 2 peg fracture?
C1/2 fixation if >50 years due to the poor blood supply. If <50 years then halo immobilisation.
What is the management of suspected VA injury?
CT head, CT-A and antiplatelet therapy (to reduce stroke risk).
Endovascular stenting may be appropriate if there is a dissection.
What is the mechanism for facet dislocation?
Flexion and distraction
What is the mechanism of a hangmann’s fracture?
Hyperextension injury causes fracture of the pars bilaterally.
Secondary flexion causes a tear of the PLL and C2/3 disc space. The C2 VB and peg are angulated forwards therefore in Type 2 fractures. In type 3 fractures there is severe angulation and displacement with facet dislocation.
What is the most common incomplete spinal injury pattern?
Central cord syndrome (70%)
What is the most common pattern of instability with os odontoideum?
Anterior instability with the os translating forward in relation to C2 body
What is the name given to the continuity of the ligamentum flavum above C2?
Posterior atlanto-axial (C2-C1) and atlanto-occipital (c1-O) membrane
What is the natural history of adult scoliosis?
< 30 deg do not progress
30-50 deg progress 10-15% over lifetime
>50 deg progress at 1 deg per year
What is the natural history of AOD?
High mortality due to lack of ventilation.
Those that survive have lower cranial nerve dysfunction and quadriplegia
What is the natural history of lower cranial nerve deficits associated with occipital condyle fractures?
Usually, improve with non-rigid immobilisation
What is the presentation of a posterior column syndrome?
Impaired proprioception, sensory ataxia - Rhomberg’s positive and tactile hallucinations.
What is the PRx?
Pressure reactivity index and is the Pearson correlation between ICP and MAP. When +1 then ICP rises with MAP suggesting that there is loss of autoregulation.
What is the risk of a type 1 congential scoliosis (formation abnormality) ?
Sharp angulation that may result in paraplegia
What is the role of Onuf’s nucleus?
Lies in rexed lamina 9 of S2 and gives origin to the pudendal nerve controlling micturition and defecation
What is the role of the medial and lateral vestibulospinal tracts?
Medial controls head and neck movements while maintaining gaze fixation
Lateral controls limb extensors and inhibits flexors
What is the role of the rubrospinal tract?
Flexor tone (and inhibits extensor tone) of the upper limbs
What is the role of the tectospinal tract?
Reflex movements of the eyes, head and neck in response to external stimuli
What is the RVAD?
The rib-vertebra angle difference at the apex of the curve. Angles >20 degrees in infantile scoliosis is associated with progression of the scoliosis and therefore need for intervention.
What is the significance of a positive rhomberg’s test?
For balance 2 out of vision, vestibular and proprioception must be intact;
The patient is asked to stand an close their eyes. If the patient cannot maintain balance this suggests a proprioceptive loss.
What is the significance of pelvic obliquity in scoliosis?
The pelvis needs to be included in that fixation
What is the significance of the Risser grade?
Risser 4 = end of spinal growth in females
Risser 5 = end of spinal growth in males
The risk of progression is lower with greater spinal maturity
What is the SLIC score?
Subaxial injury classification sore
Fracture morphology (wedge =1, burst = 2, distraction = 3, rotation/translation = 4)
Discoligamentous complex ( indeterminate = 1, disrupted = 2)
Neurological status (root injury =1, complete SCI =2, incomplete SCI =3)
Modifier = continuous cord compression in the contexts of a neurological deficit = +1
(Scores <4 = non-operative; 4 = indeterminate and 5 or > = surgery)
What is the STASCIS trial?
Surgical timing in acute spinal cord injury study
What is the surface landmark for the torcula?
The inion
What is the treatment for congential scoliosis?
Surgery!
If <5 years with curve <50 deg then posterior in situ fusion
If >5 years or curve >50 deg then anterior and posterior fusion
What is VACTERL?
Congenital anomalies of 3 of the following:
Vertebral
Anorectal
Cardiac
Trachoeo-esophageal fistula
Extensions (lung / single umbilical artery)
Renal
Limb dysplasia
What line extends laterally from the inion?
The superior nuchal line
What long term outcome studies do you know for the treatment of occipital condyle fractures?
Maserati et al - 100 retrospective cases. 3 were treated surgically for increased craniocervlcal malalignment (gap between occipital condyle and C1 lateral mass >2 mm). None of the conservatively managed patients developed delayed instability.
What mechanism causes a Hangman’s fracture?
Hyperextension / Hyperflexion + distraction
What muscle attaches below the inferior nuchal line?
Medially = rectus capitus posterior minor
Laterally = rectus capitus posterior major
What muscle attaches between the superior and inferior nuchal lines?
The semispinalis capitus
What muscle attaches to the inferior bank of the superior nuchal line?
Trapezius in the midline and sternocleidomastoid laterally
What muscle attaches to the superior bank of the superior nuchal line?
Occipitalis
What pathologies cause a complete transection of the cord?
Trauma, transverse myelitis, infarction, tumour and abscess
What proportion of cervical flexion and extension occurs at C0-C1?
50%
What proportion of cervical rotation occurs at C1/2?
50%
What proportion of patients with a syrinx have an associated syrinx?
25-85%
What proportion of patients with jumped facets fail closed reduction?
1/3
What proportion of the axial load passes through the anterior column?
80%
What proportion of the CST decussates in the medullary pyramids to form to the lateral CST?
85%
What structure can be palpated between the mastoid and the angle of the mandible?
The C1 transverse process
What type of collagen is in the annulus fibrosus? and nucleus pulposus?
Type 1 in annulus fibrosus and glycosaminoglycans and type 2 in the nucleus pulposus
What was the outcome of the CRASH trial?
Steroid are not beneficial following head injury and may result in harm
What was the outcome of the NASCIS trial?
NASCIS3 was an RCT that did not find a difference with methylprednisolone administration following SCI except in post-hoc analysis where administration <3 hours may help
What were the results of the STASCIS trial?
Prospective cohort study (not randomised)
Decompression <24 hours after SCI is safe and associated with at least 2 grades of ASIA score improvement by 6 months. Odds ratio is 2.8, so you are 2.8x more likely to improve with early surgery.
Medical complication rates were lower in those that underwent surgery
When is a CT-angiogram needed for C2 fractures?
Where there is the involvement of the transverse foramen and where C1/2 fixation is being performed.
When should an MRI be performed in a patient with jumped facets?
After closed reduction and before surgical fixation in an awake patient.
If NOT awaken then MRI should be performed prior to attempting reduction.
Where are pedicle widths the narrowest in the thoracolumbar spine?
T4-6
Where does the cuneocerebellar tract project?
Cuneate nucleus > Inf cerebellar peduncle > anterior lobe of the cerebellum
Where does the ligamentum flavum attach?
The ventral aspect of the superior lamina to the dorsal aspect of the inferior lamina. Segments run from C2 to S1.
Where does the rubrospinal tract decussate?
In the anterior midbrain tegmentum
Where does the tectospinal tract run?
Superior colliculus, decussates at level of red nucleus, descends in MLF to the spinal cord
Where is Clarke’s column (aka intermediolateral and nucleus dorsalis)?
Rexed lamina 7, contains sympathetic fibres between T1-L2
Where is fasciculus proprius?
On the outside of the spinal central gray matter
Where is Rexed lamina 9?
Front of the anterior horn - contains the cervical phrenic and spinal accessory nuclei in the neck and onuf’s nucleus in the sacrum.
Where is the 3rd segment of the vertebral artery?
Between C2 foramen transversarium and dura
Where is the C1 vertebra weakest?
Where the anterior and posterior arches connect to the lateral masses - which explains why Jefferson’s fractures occur here
Where is the second segment of the vertebral artery?
Between C6 and C2 foramen transversariums
Which cervical spinous processes are bifid?
C2-6
Which fibres terminate in the nucleus proprius?
Rexed laminae 3 & 4 - receives input from proprioception fibres
Which fibres terminate in the substantia gelatinosa?
Rexed laminae 2 &3 - input is pain, temperature and fine touch
Which foramen transversarium does the vertebral artery NOT pass through?
C7
Which muscle attached below sternocleidomastoid on the occipital bone?
Splenius capitis
Which occipital condyle fractures are considered to be unstable?
Type 3
Which rexed lamina lies around the central canal?
10
Which thalamic nucleus do the dorsal columns synapse in?
VPL > posterior limb of internal capsule
Why are C7 lateral mass screws avoided?
The lateral mass is small and therefore risks C8 root irritation.
Why are MRIs performed for occipital condyle fractures?
To assess the integrity of the craniocervical ligaments
Why is the transverse ligament integrity important for C1 fractures?
Disruption signifies C1/2 instability
What is the AO classification for thoracolumbar fractures?
A = Compression (1 = wedge, 2 = split and 3/4 = burst);
B = Distraction (1 = bony chance throughout, 2 = posterior lig complex rupture, 3 = rupture through the disc space);
C = Rotation (1 = rotation-compression, 2 = rotation-distraction, 3 = rotation-shear)
**Note in B there is failure of the anterior and/or posterior tension bands
How do missed fractures in Ank Spondylitis patients present?
Epidural haematoma
What is the TLICs score?
Morphology (1=wedge, 2=burst, 3=rotation/translation, 4=distraction)
PLC (2=indeterminate, 3=disrupted)
Neurology (2=root or complete cord, 3 =cauda equina or incomplete cord)
Note total score <4 = conservative management!
Which type of wedge fracture is most likely to need surgery?
Coronal split fractures as they fail to unite and cause significant pain
How do you manage burst fractures?
In the absence of neurological deficit and intact PLC, these can be managed conservatively in a brace.
Following standing xrays are needed. If the kyphosis increases by >10 deg or pain worsens then consider surgery.
What proportion of Chance fractures are associated with intra-abdominal injuries?
50% (liver, spleen and bowel injuries most commonly)
What structures pass through the diaphragm?
T8 = IVA and right phrenic n
T10 = oesophagus, vagus and gastric artery /vein
T12 = Aorta, thoracic duct, azygous vein
How is a kyphoplasty performed?
Transpedicular balloon expansion within the fractured vertebra followed by cement delivery
What proportion of patients develop autonomic dysreflexia?
30% of patients with lesion above T6 (required splanchnic outflow). Occurs 3/12 after SCI mediated by NorAd release.
How does autonomic dysreflexia present?
Several months post SCI patient develops sympathetic storm with hypertension, hyperhidrosis, tachycardia and vasodilation.
Which factors have best predictive value for CES?
Saddle anaesthesia and urinary retention
How do you define complete cauda equina syndrome?
Painless urinary retention, overflow incontinence and loss of executive bladder control
How does an incomplete CES present?
Reduced awareness of bladder filling,
Altered saddle sensation
Straining micturition
What was the time delay implemented in the STASCIS trial?
24 hours
What is Wackenheim’s line?
Clival line - the C2 should not transgress it unless there is basilar invagination
What is Ranawat’s line?
Height between the centre of C2 pedicle and C1 posterior arch. If <13 mm then suggests cranial settling.
What is the difference between McGregor and Chamberlain lines?
McGregor is hard palate to bottom of occiput
Chamberlain is hard palate to opisthion
What is the pavlov ratio?
The ratio of the sagittal canal diameter to the VB width. Should be 1. If <0.8 then there is a risk of neurological injury after minor trauma.
What is the rule of 12?
if BDI or BAI >12 then AOD
What weakness does C5 radiculopathy cause?
Deltoid and biceps weakness
What weakness does C6 radiculopathy cause?
Weakness in wrist extension and brachioradialis
What weakness does C7 radiculopathy cause?
Triceps and wrist flexion weakness
What weakness does C8 radiculopathy cause?
Finger flexion weakness
What weakness does T1 radiculopathy cause?
Intrinsic muscles of the hand (examined by finger abduction)
What provocative tests should be performed in patients with cervical radiculopathy?
Spurling’s test - rotation, lateral flexion and axial loading
Shoulder abduction test - ask patient to abduction shoulder and put hand on the top of head. Relief of symptoms suggests cervical radiculopathy.
What classification systems are there for cervical myelopathy?
Japan orthopaedic association
Nurick
Ranawat
What cervical sagittal alignment parameters are there?
C2-7 lordosis - cobb angle between the bottom of C2 and bottom on C7.
T1 Slope - angle between the upper endplate of T1 and the horizontal
C2 SVA - C2 plumb line distance ahead of the posterior superior corner of C7 (normal is <2 cm)
Chin-brow vertical angle (CBVA) - measure of horizontal gaze
What is the jaw jerk?
Contraction of the temporalis, masseter and medial pterygoids in response to striking the chin when mouth is open.
Exaggerated in corticobulbar disease with supranuclear lesions of the trigeminal nerve (MND, MS, pseudobulbar palsy)
How wide should a cervical laminectomy be?
>15 mm
How do you decide on ACDF vs posterior foraminotomy
ACDF - myelopathy, central compression, cervical kyphosis
Posterior foraminotomy - radiculopathy, foraminal stenosis, lordosis
What are the risk factors for OPLL?
Asian
M>F
C4-6
Diabetes
Obesity
Poor Ca absorption
What is the surgical technique favoured for OPLL?
Laminoplasty - as usually multilevel and avoids the need for fusion.
Can only be performed if spine is lordotic.
What are the labelled structures?
Cyan - longus colli
Red - anterior scalene
Yellow - middle scalene
Green - posterior scaene
What lies between the anterior and middle scalene muscles?
The brachial plexus
What is the insertion of the middle scalene?
TP of C2-7 to first rib
What is the insertion of the posterior scalene?
C4-6 to second rib
Where does the sympathetic chain run in the neck?
Between the longus colli and the anterior scalene muscles
What is the anatomical difference between the right and left recurrent laryngeal nerves?
Right vagus loops under the subclavian whilst the left vagus loops under the arch of the aorta. The right lies more laterally and runs with the inferior thyroid artery.
The left lies more medially within the tracheo-oesphageal groove. A left sided approach is less likely to result in a recurrent larygneal nerve palsy. Note a left sided approach put the thoracic duct at risk.
What are the causes of an immediate weakness following ACDF?
Traction injury, positioning or root injury during the surgery
What are the causes of a delayed weakness following ACDF?
Compressive causes - cage / graft migration (urgent imaging is needed!)
C5 palsy
Parsonage-Turner syndrome (presents with pain followed by weakness / numbness). The pain is not usually within the side dermatome.
How are C5 palsy and Parsonage Turner syndrome managed?
Physiotherapy and analgesia.
Sling can be given for C5 palsy.
Steroids are not routinely given
Most recover by 6 months
What are the delayed causes of airway obstruction following ACDF?
Implant migration
Progressive supraglottic oedema
Abscess
CSF collection
What do the recurrent laryngeal nerves innervate?
The posterior arytenoid muscles which abduct the vocal cords. A cord palsy will result in an adducted cord initially.
What the Sharp-Purser test?
A test of transverse ligament integrity.
Patient is put in a semi-flexed position
A hand is placed on the forehead and the spinous process of C2 is pushed forward. Or the patient is asked to extend their head.
A clicking sensation indicated reduction of the atlanto-axial subluxation.
What proportion of RA patients develop atlanto-axial subluxation?
60-80%
When do you operate on RA patients with atlanto-axial subluxation?
When the ADI>10mm or SAC <13mm
What operation do you perform on RA patients with atlantoaxial subluxation?
Flexion/ext xrays help to determine extent of reduction. Traction is then placed which is successful in achieving reduction in 75%..
If the subluxation is reducible then a C1/2 fixation is performed. An OC fusion may be performed if there is basilar invagination (40%).
If the subluxation is not reducible then a transoral odontoidectomy followed by OC fusion is required.
What cervicomedullary angle results in severe compression?
<135 degrees
Which levels do thoracic disc prolapses mostly occur?
T8-11
How are thoracic discectomies performed?
Anterior approach with or without fusion
(posterior approaches such as transpedicular or costotransversectomy are only for lateral soft discs)
What anterior approaches to the thoracic spine are employed?
Above T4 = Transsternal or retropleural
Below T4 = transthoracic
What are Waddell signs for non-organic back pain?
- Superficial non-anatomic tenderness
- Pain with axial compression or simulated rotation
- Negative straight leg raise with distraction
- Regional disturbances that do not follow a dermatomal pattern
- Overreaction to physical examination
What are the features of discogenic back pain?
Axial low back pain without radicular symptoms that are worse with bending / sitting / axial loading
What are the indications for lumbar disc replacement?
Single level disease with normal facet joints - patients have better 2 year outcomes and lower rates of adjacent segment disease compared to lumbar fusion alone
What proportion of patients have tandem cervical and lumbar canal stenosis?
5-25%, the cervical spine should be decompressed first followed by lumbar spine later if still required (unless they present with CES)
Which patients following lumbar fusion have a worse outcome?
According to the SPORT study, those with on-going worker’s compensation who underwent fusion have a significant increase in disability, opiate use and poor return to work.
Why can patients with L4 or L5 radiculopathy present with foot drop?
Variable L4 and L5 innervation of tibialis anterior
What are the sites of lumbar disc herniation?
Central
Subarticular
Foraminal
Far lateral
Anterior
What is the differential diagnosis in a patient with recurrent radiculopathy after microdiscectomy?
- Recurrent disc prolapse
- Perineural fibrosis
Differentiated by MRI+/-Gad
What materials are used in cages?
Titanium, PEEK and carbon fibre.
PEEK and carbon fibre allow radiological assessment of fusion. Titanium cages are stronger and improve fusion.
What is the fusion rate for an ALIF?
>90%
What factors prevent fusion?
Smoking
Previous surgery
Obesity
Multi-level fusions
Previous radiotherapy
What are the potential reasons for continued pain after fusion?
Failure to fuse
Recurrent or incomplete treatment of stenosis
Epidural fibrosis
Adjacent level disease
Infection
Implant failure
Intraoperative nerve damage
Summarise the SPORT trial (Weinstein et al 1996 in JAMA)
RCT for management of lumbar disc herniation if >6 weeks of symptoms.
501 patients randomised to open discectomy vs non-operative treatment.
Significant cross-over with only 50% of the surgical arm undergoing surgery and 30% of the conservative arm undergoing surgery. Similar outcomes in both arms.
If no spondy then decompression alone. If spondy then decompression and fusion.
Leg pain was most consistent following surgery at 2 years. Complication rate 5% from surgery with dural tear rate 4%.
In the four year outcome results pain and satisfaction were higher in the ‘as treated’ surgery group.
What are the types of spondylolisthesis?
Wiltse-Newman calssification
1 - Congenital / dysplastic (abnormality of sacrum or L5 arch)
2 - Isthmic (A - fatigue #, B - elongated pars, C - acute pars #)
3 - Degenerative (no pars facture)
4 - Traumatic (fracture anywhere other than the pars)
5 - Pathological - localised or general bone disease
What is the incidence of vertebral haemangioma?
10% at autopsy; treatment for progressive pain or neurological deficit. Treatment is surgical curettage or vertebroplasty
What are the radiological features of DISH?
Diffuse idiopathic skeletal hyperostosis = ossifiication (flowing osteophytes) of the anterolateral margins of at least 3 or more contiguous vertebra and absence of degenerative changes.
There is classically calcification of the ALL and new bone formation on the anterior surface of the vertebral body.
What is destructive spondyloarthropathy?
A rapidly progressive lumbar vertebral and disc disease seen in patients undergoing haemodialysis that resembles infection. Due to crystal induced arthropathy. Biopsy should be performed to rule out infection and for crystalline analysis.
What is the inverted radial reflex?
When the supinator jerk causes finger flexion instead of elbow flexion. Occurs when there is a root lesion affecting C5 and exaggerated UMN reflexes below C5 e.g. with a C5 disc prolapse causing radiculopathy and myelopathy.
What is the finger esape sign?
As patient to hold fingers adducted. Due to myelopathy there is weakness in the hand intrinsics and the little finger abducts.
What is the Oppenheim’s test?
Run knuckles down the tibia causing up going plantar
What is Schober’s test?
A test of lumbar flexion.
Mark a line between the PSIS bilaterally.
Place a tape measure 10 cm above and 5cm below (15 cm). When the patient flexes forward this should increase by >5 cm.
What is Lasegue’s test?
Straight leg raise
What is the equivalent of the straight leg raise for L2/3 and L3/4 disc prolapses?
Femoral stretch test (patient prone with knee bent. Extend the hip by lifting the foot)
What level does the abdominal reflex check?
T7-12
What is the bulbocavernosus reflex?
Loss of involuntary anal contraction when squeezing the glans penis / clitoris. Loss after SCI suggests spinal shock.
How do you distinguish shoulder pain from cervical radiculopathy?
Shoulder test. Abduct the arm and place the hand on top of the head. If the pain improves then suggests cervical radiculopathy.
Define disc bulge, extrusion and protrusion.
Bulge is up to 3 mm beyond the endplate >50% of the disc space
Extrusion is where the base of the herniated disc is small than the AP dimension
Protrusion is where the base of the herniated disc is greater than the AP dimension
What is the difference between a migrated and a sequestered disc?
Migrated is still in continuity with the disc space whilst a sequestered disc is no longer in continuity
What are the risk factors for spinal infection?
IVDU
DM
Renal failure
Pregnancy
Previous trauma / surgery
Immunosuppresion (AIDS / steroids etc)
Which organisms are most likely to cause a spinal infection?
Staph, Strep, E.Coli, Pseudamonas
How can a pyogenic spinal infection be distinguished from TB on imaging?
Pyogenic infections are disc centered whilst in TB the disc is relatively preserved
Which subgroup of patients are more likely to have a pseudamonas discitis?
IVDU
How long does it take for MRI features of discitis to appear?
>4 weeks. Disc space narrowing is the first sign.
Which imaging modality shows early spinal infections (before xrays and MRI)?
Technetium-99 bone isotope scan
What is the diagnostic yield of a CT guided biopsy?
70%
What tests would you request for a CT guided biopsy for discitis?
MC&S with gram stain
AFB (TB PCR, Ziehl-Neelson stain and Lowenstein-Jensen agar)
Fungal cultures
Histology to distinguish chronic infection from neoplasia
What are the considerations for treating osteomyelitis?
Diagnosis
Debridement
Eradication of infection
Prevent neurological deficit
Preservation of stability
Correction of deformity
Relief of axial pain
Which factors are most likely to respond to non-surgical treatment for spinal infection?
Staphylococcus aureus
Age <60
Primary disc disease with minimal bone involvement
Minimal kyphotic deformity
No neurological deficit
No systemic disease
No immunosuppression
What are the indications for surgery in spinal infection?
Diagnosis
Abscess drainage
Failure of medical therapy
Stabilisation
Correction of deformity
Neurological decompression
What is the preferred approach for spinal infections?
Anterior (+/- posterior) as the disc and vertebral bodies are most commonly affected so anterior column support is needed.
Posterior approaches can be performed if below the conus
What type of implant is used for stabilisation in the context of infection?
Titanium alloy > stainless steel as biofilms are less likely to form on titanium.
What are the patterns of spinal involvement with TB infection?
Peridiscal - infection adjacent to the endplate spreads to the next vertebra under the ALL sparing the disc space
Central - infection is within the middle of the vertebral body causing collapse and kyphotic deformity
Anterior - Infection is beneath the ALL and causes scalloping of the VB, usually over multiple levels
How does TB infection present?
Fever
Night sweats
Kyphotic deformity (Gibbus)
Neurological deficit (40%)
What are the histological findings of spinal TB infection?
Multinucleated giant cells surrounding a central region of caseating necrosis
How do you investigate a patient with suspected spinal TB?
FBC, ESR / CRP, LFT
CXR
CT CAP - evaluation of extraspinal disease
CT spine
MRI spine
CT guided biopsy
What is the managment of spinal subdural infection?
Aggressive surgical treatment followed by antibiotic therapy.
**LP should not be performed due to risk of seeding into the subarachnoid space
What is the treatment of an intramedullary spinal cord abscess?
Laminectomy, intradural exploration, midline myelotomy, drainage of abscess
IV abx 6 weeks
The rest of the neuro-axis should be imaged for spread of infection
What is the most common extradural spinal tumour in adults?
Metastases (90%) - Breast > Lung > Prostate > Renal
What are the commonest extradural primary spinal tumours?
Benign - osteoid osteomas, osteoblastoma, osteochondroma, aneurysmal bone cysts and haemangiomas. Langerhan’s histiocystosis in children!
Malignant - Osteosarcoma, chrondrosarcoma, giant cell tumour, plasmacytoma, , Ewing’s sarcoma and chordoma.
Where do intradural extramedullary lesions most likely arise?
The thoracic spine (meningiomas and peripheral nerve sheath tumours)
What is the diagnosis?
Osteoblastoma - these are >2cm. They have a very rich blood supply so preoperative embolization aids in the resection. Complete resection is curative.
Predominantly affects adolescents / young adults and causes night pain that is relieved by aspirin.
What is the diagnosis?
Osteochondroma - single or multiple lesions that most commonly affect C2. Present with pain. M>F. Have a core of cortical and medullary bone with a cap made of hyaline cartilage. Can undergo malignant degeneration
What is the diagnosis?
Aneurysmal bone cyst - highly vascular tumours that present in the first 2 decades of life. A well circumscribed lytic lesion with periosteal calcification - soap bubble appearance. Fluid levels are strongly suggestive of an ABC. Surgical excision is curative. Histological examination is needed to exclude other malignant pathologies!
What is the diagnosis in this child with neck pain?
Langerhans cell histiocytosis - causes destructive lesions mostly in the C>T>L spine. In the absence of deformity aggressive surgical management is usually not indicated. Unknown aetiology but characterised by the accumulation of histiocytes.
What is the diagnosis?
Osteosarcoma - prognosis is poor. Management is with en-bloc resection, chemo and radiotherapy. Present with pain and neurological deficit. Paget’s disease is a risk factor. Osteoblastic and chrondroblastic are the most common subtypes.
What is the diagnosis?
Giant cell tumour - extraosseous extension at sites of coritcal destruction and extension into the spinal canal. Note that there is no internal bone matrix within the lesion that would be present with an osteoblastoma. Histology shows multinucleated giant cells with bone infiltration but no necrosis (as would be found in TB!).
What is the diagnosis?
Plasmacytoma - discrete solitary bone or soft tissue lesion composed of monoclonal plasma cells. Unlike multiple myleoma there is no systemic bone marrow involvement.
Punched out lytic lesion with erosion and destruction of the bone.
Management with radiotherapy +/- surgery depending on location and stability. These are highly radiosensitive.
What are the epidemiological features of multiple myeloma?
Most common malignancy in patients >40 years
M:F 2:1
Present with bone pain, anaemia, renal failure and proteinuria (CRAB = calcaemia, renal failure, anaemia, bone pain)
What are the laboratory findings for multiple myeloma?
Low albumin : High globulin
Monoclonal gammopathy
Bence Jones proteinuria (Ig light chain)
High Ca
High serum Beta-2 microglobulin (a prognostic marker for response to chemo and overall disease burden)
What is the second most common primary malignant bone tumour in children?
After osteosarcoma is Ewing’s sarcoma. Destructve lucent lesions without osteoid matrix. Classically has onion skin periostitis. Small round blue cell tumour closely related to PNET. Typically affects the long bones.
What do chordomas arise from?
Embryonic remnants of the notochord
What are the microscopic findings of chordoma?
Physalipherous cells.
What is the most common spinal cord tumour overall?
Ependymoma
What are the clinical features of spinal ependymomas?
Median age 40
M>F
Associated with NF2
Arise from ependymal cells of the central canal or filum
What are the subtypes of spinal ependymoma?
Cellular (most common)
Papillary
Clear cell
Tanycytic
Myopapillary
Melanotic
**Myxopapillary are grade 1, the others are grade 2 or rarely 3
Where do myxopapillary ependymomas arise?
The filum terminale / cauda equina
What are the radiological features of an ependymoma?
Central cord lesion with associated syrinx and haemosiderin cap
Bright contrast enhancement
What are the features of spinal haemangioblastoma?
Associated with VHL in 1/3 (rest are sporadic)
WHO grade 1 - very vascular (preop embolization may help)
Mural nodule with cyst
Can be differentiated from renal cell ca mets by staining for Inhibin A
What are the features of spinal cord astrocytomas?
Arise from the spinal cord parenchyma (eccentric), cause expansion of the cord and have poorly defined margins.
Low grades do not contrast enhance.
In children behave like pilocytic astrocytomas
Associated with NF 1
Which tumours metastasise to the spine?
Breast > prostate > lung > kidney > thyroid
What is the mechanism by which spinal metastases cause bone lysis?
The tumours releases cytokines incl PTHrP and TGF beta.
Both of these increase osteoblast activity.
Osteoblasts release RANK-ligand which stimulated osteoclasts to break down bone.
(Prostate mets also secrete Endothelin-1 which stimulates osteoblasts also)
What is the Tokuhashi score (revised 2005)?
Prognostic score for patients with metastatic spine disease.
Based on 6 factors: Karnofsky, No. of extraspinal bony mets, number of VB mets, No. of visceral mets, primary tumour and Neurological deficit.
If score <8 then < 6months, 9-12 then >6 months survival and 12-15 then>1 year survival
Note, the revised score took primary tumour site into account more
How does the Tomita prognostic score differ from Tokuhashi?
The higher the score with Tokuhashi the better the prognosis. With Tomita, the lower the score the better the prognosis.
What is the goal of palliative radiotherapy in patients with spinal mets?
8Gy single fraction is given for non-mechanical pain even if paralysed
In the absence of instability vertebroplasty can be peformed for mechanical pain
What are the immediate management steps for suspected MSCC?
- Spinal immobilisation - flat bed rest
- Dexamethasone
- Whole spine MRI and CT
What are the contraindications for radiotherapy in MSCC?
No histological diagnosis
Radio-resistant tumours
Spinal instability
Previous radiotherapy to the region
Which spinal tumours should be treated with chemotherapy (not radiotherapy)
Germ cell tumours (teratomas, yolk sac, choriocarcinoma)
What is a normal prevertebral thickness?
Above C4 <8 mm, below C5 <18 mm (due to the oesophagus)
What are the indications for surgery in MSCC?
Fit for surgery
No neurology or <24 hours paralysis
Single or continguous areas of compression
Expected survival >3-6 months (depending on the surgery)
Spinal instability
Pain resistant to conventional therapy
Prevent impending neurological compromise
Histological diagnosis
Cytoreduction / Monobloc resection (e.g. solitary renal or thyroid mets)
Summarise the Patchell et al 2005 Lancet study
RCT comparing decompression + RT vs RT alone for MSCC
Stopped early at 50% recruitment as surgery superior
30Gy in 10 fractures to both arms
Improved ambulation (duration / maintenance / return), functional ability, power and continence compared to RT alone.
Surgery+RT survival 126 days; RT alone 100 days.
Note: radiosensitive tumours were excluded (small cell, lymphoma and myeloma)!
What proportion of spinal mets do not have a primary?
10-20%, therefore a biopsy / histological diagnosis is required
What is the diagnosis?
Cellular ependymoma. Other common subtypes are myxopapillary and anaplastic subtypes
Which primary bone tumours may seed along the biopsy tract?
Chordomas / osteosarcomas
What factors should be considered regarding the approach to MSCC surgery?
- Location of the tumour within the vertebra
- Spinal segments involved
- Reconstruction method required
- Histology
How does radiation myelitis present?
Acutely with transient myleopathy and Lhermitte’s sign (within 3-4 months of treatment) - usually self-limiting as due to demyelination
Delayed (20-30 months) - presents with progressive weakness due to demyelination and white matter necrosis.
Pathology is due to oligodendrocyte injury and microvascular injury
**local recurrence must be ruled out before making this diagnosis**
Where are myxopapillary ependymomas most likely located?
Conus medullaris and filum terminale
Why can myxopapillary ependymomas appear hyperintense on T1?
Mucin and haemorrhage content
Should radiotherapy be given after myxopapiillary ependymoma resection?
Controversial. Unclear if beneficial after GTR. Some evidence that irradiation improves outcomes in paediatric patients.
What is the treatment of choice for ependymoma?
Gross total resection
What is MISME syndrome?
Multiple inherited schwannomas, meningiomas and ependymomas. Seen in NF-2 (ch22), NF-1 (Ch 17), Tuberous sclerosis (Ch 9 and 16) and Neuroblastoma (Ch 11).
How do you treat spinal astrocytomas?
Low grade - maximal safe resection (difficult to achieve except in pilocytic astrocytomas), then observe and hold radiation for recurrence.
High grade - Maximal safe resection followed by chemo and radiotherapy (extrapolation of the Stupp protocol)
What further investigations are required for patients with haemangioblastomas / VHL?
Opthalmology - to rule out retinal haemangioblatomas
Brain MRI - other CNS haemangioblastomas
CT abdomen - renal tumours
What are the management options for cerebellar haemangioblastomas?
Surgical excision or SRS.
Note: SRS has not been evaluated for spinal haemangioblastomas so GTR remains the mainstay of treatment
What is the most common type of nerve sheath tumour?
Schwannoma
Where are most spinal schwannomas located?
Encompassing the dorsal sensory root (lumbar > cervical)
Classically have a dumbbell shape and widen the neural foramen
NF-2 patients often have multiple schwannomas.
Resection requires sacrifice of the rootlets (most often dorsal sensory rootlets)
**Surgery is the mainstay of treatment
Which extra-axial spinal lesion is most likely associated with NF-1?
Neurofibroma
(note meningiomas are related to NF-2)
Note NF-1 is associated with transformation to MNST characterised by rapid growth and pain
Which condition are axillary / inguinal freckling and iris Lisch nodules associated with?
NF-1 (Ch 17 - neurofibromin gene)
How are schwannomas different to neurofibromas on MRI?
Schwannomas typically exhibit asymmetric growth and displace the nerve root, whilst neurofibromas result in fusiform encasement of the root.
What are the features of benign peripheral nerve sheath tumours on MRI?
Isointense on T1
Hyperintense T2
Bright contrast enhancement
What are the features of spinal lipomas?
Bright on T1 and T2
Dark with fat saturation sequence
Associated with occult spinal dysraphism
Intimately related to cauda equina. Complete resection difficult. Surgery should be conservative to relieve symptomatic compression
What are the features of spinal meningiomas?
25% of all spinal neoplasms
5x more common in females
Age at diagnosis 50 years (younger patients have NF-2)
Most occur in the thoracic spine (younger patients have more cervical lesions)
What are contraindications to spinal SRS?
Neurological deficit due to MSCC (as surgery is needed to decompress)
Instability
Previous RT with maximal tolerable dose delivered to spinal cord
Note, SRS can be given to radioresistant tumours (renal cell / melanoma)!
What is the most common intradural extramedullary lesion in western countries?
Meningiomas (note this is schwannoma in china / japan)
What is the cause of vertebra plana in the thoracic spine of a 7-year-old?
Eosinophilic granuloma
Label the vessels
- Posterior spinal arteries (x2)
- Anterior spinal artery (x1)
- Anterior Radiculomedullary artery (largest of which is Adamkiewicz)
- and 5. Medial and lateral muscular arteries
- Posterior radiculomedullary artery
- Retrocorporeal arteries
- Spinal branch
- Dorsal (muscular) branch
- Ventral (intercostal / lumbar) branch
- and 12. Segmental artery
What is a honey comb pattern (jail house striations) associated with?
Haemangioma
Where does the artery of adamkiewicz arise?
T9-12 (80% left side)
Describe the segmental blood supply to the spine
Segmental arteries come off the aorta.
Segmental artery branches into ventral, dorsal and spinal branches
Ventral branches supply intercostal and lumbar regions
Dorsal branches supply the paraspinal muscles and skin
Spinal arteries form the retrocorporeal and radicular branches which supply the anterior spinal artery
Radicular arteries are radiculoradial to nerve root, radiculopial to pia and radiculomedullary to anterior and posterior spinal cord
Describe this spinal AVM
Type 1 dAVF with abnormal connection at the root sleeve between the radicular artery and vein. This is a type A because there is only one arterial feeder.
Describe the spinal AVM
Type 2 - intramedullary glomus AVM with the nidus in the parenchyma of the cord. Classified as compact or diffuse.
Describe the spinal AVM
Type 3 juvenile AVM - which has intra and extradural components that typically involve the spinal cord, VB and muscles.Part of Cobb syndrome which has skin lesions corresponding to the dermatomes of the spinal levels where the lesion is.
Describe the spinal AVM
Type 4 intradural perimedullary fistula with the fistula on the pial surface of the spinal cord (usually anterior). The spinal arteries shunt into the spinal venous plexus.
If type A ASA supply only then surgery
If type B ASA and PSA then embo prior to surgery
If type C giant with ASA and PSA with dilated segmental veins then embo only
What are the features of this pathology?
80% of all spinal AVMs. M>F presenting between 40-60y. Congestive venous myelopathy causes slowly progressive neurological deterioration. Venous disconnection is the goal of surgery.
What spinal AVM is associated with HHT / Rendu-Osler-Weber?
Type 4 perimedullary AVF
What is this spinal AVM?
Type 2 glomus AVM with tight intramedullary nidus
What is Foix-Alajouanine syndrome?
Venous congestive myelopathy - most likely due to dural AV fisutal
What is the Bao & Ling (1997) classification of spinal vascular malformations?
1 - Dural AVF - between a radiculomedullary artery and radiculomedullary vein. The fistual is at the dural root sleeve. Type A have a single feeder. Type B have multiple feeders
2 - Intramedullary glomus AVM - Fistula within the spinal cord. Feeders can come from ASA, PSA and radiculomedullary arteries.
3 - Juvenile AVM - Rare AVMs of the cord, vertebra and paraspinal tissues.
4 - Perimedullary AVF - Thoracolumbar fistula between ASA and anterior spinal vein on the ventral cord surface. Type A - small with single ASA feeder, B - medium sized, C - giant sized
- Extradural
What is the most common source of spinal extradural haematomas?
Venous.
If the blood cannot be found then do US as may need to open the dura to make sure it is not intradural
Describe how blood changes on MRI with time
OxyHb is iso on T1 and T2 and becomes deoxy-HB within 1-2 days.
De-oxyHb appears iso on T1 and dark on T2.
De-oxyHb becomes intracellular metHb after 2-7 days and is bright on T1 and remains dark on T2.
Intracellular metHb becomes extracellular after 7-28 days which is bright on T1 and T2
After 28 days Haemosiderin forms which is dark on T1 and T2
What is the treatment for type 2 spinal AVMs?
Surgical excision with or without embolization first
What is the Hufschmidt grade?
Clinical symptom grading of spondylolisthesis
What are the types of lumbar canal stenosis?
Central, lateral and foraminal
What % of disc herniation are in the thoracic spine?
1% (mostly T11/12)
Between which levels can a thoracic disc prolapse cause Horner’s syndrome?
T2-5
What are the approaches to a thoracic disc prolapse?
Anterior (transthoracic)Posterior lateral (transpedicular, costotransversectomy, lateral extracavitatory approach)
What investigation should all patients with a thoracic disc have prior to surgery?
CT scan!! As likely calcified.
What are the stages of degenerative disc disease?
Dysfunction - poor biomechanics resulting in painInstability - aberrant motionRe-Stabilisation - fusion to immobilise the area
Which nerve is thought to cause discogenic pain?
Sinoverterbral nerve
What is the equation for momentum?
Momentum = force X distance
What is IAR?
Incidence of angular rotation
What aspect of a screw governs the pull out strength?
The thread depth
What aspect of a screw governs the screw fracture strength?
The inner diameterThe screw fracture strength is proportional to the diameter cubed
What is the definition of the functional spinal unit?
The two vertebral bodies, intervening disc and facet joints
What is normal Sagittal balance?
Centre of C2 runs to the anterior T7, middle of T12 and posterior L3 and ?S1
How are fractures classified with AO classification?
A - Compression
B - Distraction
C - Rotation / translation
These are each subdivided into 1-3
How do you classify occipital-cervical dislocation?
A - Head forwardB - Head vertical displacementC - Head backwards
How can you measure occipito-cervical dislocation
Powers ratioBDICCI (Condylar gap) >2mmBAIX-line
What is the classification of occipital condyle fractures?
Anderson: 1 - Comminuted condyle2 - Extension of skull base fracture3 - Avulsions of the condyle
What is the rule of spence?
Overhang of the C1 over C2 >7mm when combined suggests transverse ligament injury
How do you manage Jefferson fractures?
Transverse ligament intact - HaloTransverse ligament not intact - Surgery
What is C1 osteosynthesis?
Bilateral C1 lateral mass screws with a connector between the screws to treat Jefferson’s fractures
What fractures occur of C2?
Peg fractures (Anderson D’Alonzo classification)Hangman’s (Effendi classification)Ring fractures
What is the Effendi classification?
1 - <3mm displacement
2 - 3-5 mm displacement
2a - >11 degrees angulation (C2/3 disc space rupture)
3 - C2/3 facet joint dislocation
What does the bulbocavernous reflex tell you?
Lack of supra spinal input to the sacral outflow is suggestive of a complete spinal injury
What are the Canadian c-spine rules?
Image if:1) >65 years2) Dangerous mechanism3) Parasthesia in extremities
What is the pB-C2 line?
A line drawn through the odontoid tip from the ventral dura perpendicular to a second line drawn from the basion to the inferoposterior aspect of C-2 vertebral body.If the peg is >9mm behind this line then basilar invagination exits
Which fracture should not be placed into traction?
Occipital-cervical dislocation Hangmann’s type 2A
How can a burst fracture be diagnosed on AP X-Ray?
Widening of the interpedicular distance.
What are the types of spondylolisthesis?
Degenerative - due to facet degenerative changesIsthmic - has bilateral pars defectsTraumaticCongenital2 more
What is the management of Chordoma / chrondrosarcoma of the spine?
Total enbloc resection
How do you calculate prognosis in patients with spinal metastasis?
Tokuhashi score: General conditionNumber of extra spinal bone metsNumber of bone metsVisceral metsPrimary site of cancerSpine cord involvementTotal is 15; If 9 surgery, 6-9 unclear
What is the most likely diagnosis of an extramedullary intradural tumour?
Meningioma / haemangiopericytomaSchwannomasNeurofibromas (need to sacrifice the nerve root)Ependymoma (myxopapillary)CavernomaMets etcDermoid
What is the diagnosis of an intramedullary intradural spinal tumour?
Low grade astrocytomaEpendymoma (homogenous enhancement, arachnoid capping cysts or syrinx associated)SubependymomaHaemangioblastoma (florid contrast enhancement with large syrinx - get an angiogram!)Vasculitis/ Demyelinating lesion / Sacroid
Where are spinal haemangiocytomas?
Subpial
What are the symptoms associated with Chiari malformation?
Cough headacheLower cranial nerve dysfunctionDysphagiaLimb symptoms associated with syrinx
What is platybasia?
When the angle of the Clivus is >143 degrees
What is the classification of Basilar Invagination?
Goel classification: 1) Reducible - Unstable with tip of peg above chamberlain, McRae and wackenheim’s line - needs reduction and C1/2 fixation. These tend not to have an associated Chiari 2) Irreducible - need to have anterior odontoid peg resection (transoral) plus posterior fixation. These tend to be associated with a Chiari.
How can bone mineral density be estimated from CT?
BMD (mg/ml) = 0.78 X Hounsfield unit
What are the contraindications to vertebroplasty?
Coronal split fractureVertebra planumPosterior wall breach
Why is the risk of cement extrusion less with kyphoplasty?
As the balloon creates a cavity which is filled with low pressure cement
What proportion to the population suffer from RA?
1%
What is the aetiology of instability in the spine with RA patients?
Immune complex deposition causes ligamentous laxity and instability. This leads to pannus formation and neurological compression
What is the difference between basilar invagination and cranial settling?
Basilar invagination has C1/2 instability I.e. C1 is in the normal position; with Cranial settling the C1/2 and normal and the whole complex has migrated cranially
What is the differential diagnosis of an intradural spinal lesion (extra / intramedullary)?
MeningiomaSchwannomaNeurofibromaChordomaMyxopapillary ependymoma
What are the radiological features of a solitary fibrous tumour?
T2 =
iso- to hypointensity (the best clue to the diagnosis)
heterogeneous signal: “yin-yang” appearance of separate areas with low signal and high signal intensity may be characteristic
flow voids commonly seen
T1 C+ =
vivid diffuse heterogeneous contrast enhancement of low T2 signal components
dural tail may be seen, but is much less common than in meningiomas
What are the radiological features of a benign vs malignant peripheral nerve sheath tumour?
Look it up
What is the differential diagnosis of an intradural lesion at the conus?
Myxopapillary ependymomaParagangliomaCavernomaDermoidsLipomaDermoid
What is the differential of an intramedullary spinal lesion?
Low grade astrocytomasEpendymoma (usually central and homogeneous)SubependymomaHaemangioblastoma (pial location on the surface of the cord)CaveromaInflammatory lesion
What are the radiological features of a spinal haemangioblastoma?
Haemangioblastomas are associated with large syrinxes!! Get an angiogram !! Take the feeders
What are the general principles of spinal intramedullary surgery?
Adequate laminectomyLarge durotomyAdequate myelotomySurgical plane better centrally at the edges and worse at the polesDebulk with CUSAWater tight dural closureLaminoplasty for children
When would you do a posterior foraminotomy / discectomy?
Soft discs affecting the root unilaterally(Best if sequestered)
What is the differential diagnosis of an expansile destructive lesion of the spine?
What is the differential of a lytic vertebral body lesion?
Metastasis
Chordoma
Osteoblastoma
ABC
Giant cell tumour
What is this lesion?
No central trabeculation otherwise would be an osteoblastoma
What is this lesion?
Osteochondroma
What is the diagnosis?
Polka dot sign on CT
Hyperintense on T1 and T2
What are the causes of hyperintense vertebral bodies?
Haemangioma
Radiation
Paget’s disease
Modic changes
What is the evidence for surgery for cervical spondylotic myelopathy?
Fehlings et al. (2015): surgery improved clinical outcomes, functional status and quality of life. 479 symptomatic patients with image evidence of CSM. A prospective, multicenter study. The improvements after surgical decompression were sustained at 1 year and 2 years after surgery.
