Spine Flashcards
unilateral facet dislocation X-ray finding and presentation
leads to ~25% subluxation on xray
associated with monoradiculopathy that improves with traction
bilateral facet dislocation X-ray?
leads to ~50% subluxation on xray
often associated with significant spinal cord injury
Mechanism and location of cervical facet fracture and dislocation
flexion and distraction forces +/- an element of rotation
What levels do cervical facet fractures occur at most often?
~75% of all facet dislocations occurred within the subaxial spine (C3 to C7)
17% of all injuries were fractures of C7 or dislocation at the C7-T1 junction
reinforces need to radiographically visualize the cervicothoracic junction
Flexion distraction injuries of the c-spine according to Allen-ferguson have four stages, what are they?
Bonus: what ligament is intact in unilateral dislocations but not bilateral? What ligament is intact in both?
Stage 1: facet subluxation
Stage 2: unilateral facet dislocation
Stage 3: bilateral facet dislocation with 50% displacement
Stage 4: complete dislocation
PLL/ALL
Role of MRI in cervical facet dislocations after successful closed reduction, how do they guide treatment?
Surgical stabilization following successful closed reduction
PSF or ACDF can be performed in the absence of significant disc herniation
ACDF performed if significant disc herniation present
What improves cervical radiculopathy?
Shoulder abduction
Treatment of odontoid fractures in elderly.
Taken from JAAOS Hsu et al 2010
Type 1 and 3: collar
Type 2 stable: collar
Type 2 unstable: Posterior C1-2 fusion
Posterior C1-2 fusion high rate of morbidity and mortality in this age group (approx 20%) but still lower than use of a halo-vest (approx 40%).
A nonunion of type 2 is acceptable in this age group provided no s/s of myelopathy. Hence OK to treat stable 2s in a collar alone.
Treatment of odontoid fractures in non-elderly.
Taken from JAAOS Hsu et al 2010
Type 1 and 3: Collar Type 2b (Grauer modification with fracture line anterosuperior to posteroinferior): Good pattern for anterior odontoid screw.
Type 2: Low risk: Use halo-vest (or collar, but collar associated with higher nonunion rate (50% vs 30% with halo vest)
High risk: Surgical. Dealers choice of anterior screw, vs posterior C12 fixation, etc.
Risk factors for odontoid nonunion
Age >40 Posterior displacement >5mm Angulation >11 degrees Neurologic deficits Comminution of fracture
Ekong et al (from the Hsu JAAOS article 2010)
Describe harris lines and rule of 12
BAI: basion-posterior axial interval
BDI: basion-dens interval
Each should be 12 or less
List 7 ligamentous constraints of the upper C spine
Tectorial membrane (PLL)
Cruciate ligament (which includes transverse ligament)
Alar ligments (dens to condyles)
Apical ligment (dens to basion)
Nuchal ligament (external occipital protuberance to the posterior atlas and spinous processes)
Superior continuation of ALL
Superior continuation of ligamentum flavum
Outline treatment for occipital condyle fractures for types 1-3
Type 1. (comminuted condyle from compression/impaction mechanism). Stable and treat in collar
Type 2. basal skull # extending into condyle. Stable and treat in collar
Type 3. Associated with avulsion off condyle. If stable can be treating with collar. If unstable should to O-C2 fusion. Stability can be sorted out with dynamic manual traction under fluoro, or halo traction with lateral imaging. Any distraction >2mm means it’s unstable (either fracture distraction or O-C distraction.
Indications for Rigid Collar or Halo in atlas fracture
Isolated anterior or posterior ring fracture (with intact transverse ligament)
Stable burst (jefferson) ie. with combined lateral mass displacement of less than 7mm
Stable unilateral lateral mass fracture (may need MRI to sort out when transverse ligament intact to confer stability)
Indications for surgery in atlas fractures
- Plough fracture (dens driven through anterior arch of C1)
- Unstable burst (jefferson) with combined lateral mass displacement of >7mm
- Unstable unilateral lateral mass fracture (ie. transverse ligament ruptured).
If reducible in supine traction but displaces when you attach halo, can just leave them for 6 weeks in traction.
Usually Occ to C2 fusion, option to Atlas ORIF but not easy.
Levine and Edwards classification of Hangman’s #
- Bilat pars fracture minimally displaced. HALO.
1A. Unilat pars with contralateral body fracture. (side bend mechanism). HALO. - Bilateral pars # with >3mm translation
Reduce with traction/extension and use Halo vest 12 weeks. Mechanism is rebound flexion after hyperextension and axial load. Stable to apply traction. Can operate if residual displacement after reduction. C1-3 posterior or C23 ACDF.
2A. Bilateral pars # with more oblique pattern. Usually angulated moreso than translated. Associated with C23 disc and PLL disruption because mech is flexion/distraction. Interspinous ligs gone too. Very unstable (ALL is only thing intact). Reduce in extension. Do not apply traction!
Tx: HALO if reduces, if still displaced do C23 ACDF or posterior C1-3 fixation.
- Bilateral pars # with C23 facet dislocations.
Mech is hyperflexion then hyperextension. Mandatory to do posterior open reduction (won’t be able to reduce with traction). Options are C1-C3 fusion. Or preserve atlantoaxial motion by placing interfrag screws in C2 across fracture and fuse to C3.
Must use halo postop.
SLIC classification
Morphology: Compression 1 Burst 2 Distraction 3 Translation 4
Discoligamentous:
Intact 0
? 1
Disrupted 2
Neuro: Intact 0 Root involvement 1 Complete 2 Incomplete 3 Add +1 for continuous cord compression
NONOP 3 or less
4: consider for surgery
5: operative
C - spine stability (White and Panjabi)
Unstable if >5points
2 points each:
Anterior element injury, posterior element injury, translation >3.5mm, kyphosis >11deg, positive stretch test >1.7mm, SC injury
1 point each:
Root injury, abnormal disc space narrowing, dangerous anticipated loads
Orthobullets adds: >25% vertebral body height loss
List factors that may preclude use of C1-2 transarticular fixation
Medial VA trajectory
Hypoplastic C2 pars
Irreducible C1 C2 position
Large thoracic kyphosis blocking low trajectory.
2 risks with anterior penetration during C12 transarticular screws
Internal carotid artery
Superior hypoglossal nerve
Preop predictors for clinical outcome in LSS surgery? HINT: Radiologic Comorbidities Depression Symptoms
Aalto et al Spine 2006
“Preoperative Predictors for Postoperative Clinical Outcome in Lumbar Spinal Stenosis”
Radiologic:
- AP stenosis diameter = 6mm on myelogram predicted less pain postop
- Stenosis cross-sectional area on MRI = 70mm2 had better postop Oswestry score than CSA >70mm2.
- Preop scoliosis predicted worse postop pain.
Comorbidities:
- Better preop walking capacity predicted better postop walking capacity.
- Preop cardiovascular comorbidity predicted worse outcomes.
Depression:
-Depression and unrealistic expectations did worse.
Symptoms:
- Shorter symptom duration associated with less postop pain (in lateral stenosis only).
- Preop back-dominant pain had worse satisfaction.
Straight leg raise tests which roots?
Femoral nerve stretch tests which roots?
SLR: L4-S3
FN:L2-L4
Does duration of symptoms matter in lumbar spinal stenosis WRT outcomes?
Radcliff et al 2011 SPINE
(subgroup analysis of SPORT trial)
Patients with duration of symptoms 12 mos.
For patients with degenerative spondy, there was not difference in outcomes with respect to duration in symptoms.
What are the anatomic borders of the lateral recess
Posterior: superior articular facet
Anterior: Disk and vertebral body
Medial: Thecal sac
Lateral: Pedicle
4 radiographic signs of instability in lumbar degenerative spinal stenosis.
Spondylolisthesis on lateral xray
Lateral listhesis on AP xray
Widened facets on T1 MRI
Fluid-filled facets on T2 MRI
Complications with laminectomy (isolated) for LSS
2012 JAAOS Issack et al
Dural tear 10% (does not affect outcome)
Infection 2%
Postlaminectomy Instability 3.7%
Epidural hematoma (rare)
Adult isthmic spondy - which level at higher risk of slip progression? L45 or L5S1?
L45 higher risk of slip progression
JAAOS Jones et al 2009, pg 610
Compare and constrast DISH vs AS
DISH: non-marginal syndesmophyes (candle wax) @ min. 3 consecutive levels No SI involvement HLA B27 negative Tends to be older age Disk space preserved No osteopenia RF: gout, DM, hyperlipidemia. Can have hoarseness, dysphagia
AS: Marginal syndesmophytes (bamboo spine) SI joints involved first (spine later, +/- uveitis) HLA B27 usually positive RF usually negative Younger patient (20s-30s at onset) Disk space ossifies Yes osteopenia Other probs include cardiac conduction, aortitis, pulm fibrosis, renal amyloidosis Have
In spine mets, surgery then rads? OR rads then surgery?
Surgery first, rads second is better.
Patchell: patients who had rads first then crossed over to surgical arm did worse.
JAAOS 2011
Factors influencing choice of Ant vs Post c spine approach in myelopathy.
Sagittal alignment Number of levels (disease extent) Location of compressive pathology (ant or post) Premorbid neck pain Any prior operations
Anterior approach to lumbar spine. Nerve on psoas? Two nerves lateral to psoas?
On psoas: genitofemoral
Lateral to psoas: Ilioinguinal & Iliohypogastric
Outline ECOG stages for determination of performance status in spinal mets patients
ECOG
0 Fully active: able to carry on all predisease activities without restriction
1 Restricted in strenuous activity; ambulatory; able to perform light work
2 Ambulatory; able to perform self care; unable to work; bedridden ≤50% of the time
3 Limited self care; bedridden ≥50% of the time
4 Completely disabled; incapable of self care; bedridden
Mechanism (4) of steroid treatment in metastatic spine lesions.
Dose of steroids?
Reduce vasogenic edema
Reduce inflammation
Stabilize liposomal membranes
Some tumourlytic effect in MM/Lymphoma
100mg IV Decadron, then 24mg IV q6h
Common treatment algorithm for spine rads to metastatic spine disease.
30 Gy in 10 fractions
In spine mets, surgery then rads? OR rads then surgery?
Surgery first, rads second is better.
Patchell: patients who had rads first then crossed over to surgical arm did worse.
Also, surgery then rads much better than rads alone.
JAAOS 2011
Spinal Instability Neoplastic Score (SINS)
Location in spine Pain relief with recumbancy Type of lesion (lytic, blastic, etc) Malalignment Vertebral collapse Posterior element involvement
Outcomes of PSF alone vs circumferential fusion for low-grade adult isthmic spondy.
JAAOS 2009 Jones
Better clinical outcomes reported with PSF combined with ALIF/PLIF vs PSF alone.
Take home message from SPORT trial
JAAOS 2012 Asghar
HNP: randomized cohort - surgery better but not stat significant. OBS cohort - as treated analysis, surgery statistically better. Magnitude of treatment effect not as high with HNP.
DS and LSS: high level of crossover. As treated analysis of OBS cohorts show very significant benefit to surgery.
Overall: 2-3 % infection, 10% dural tear (3% in HNP), 10-15% reoperation rate. No paralysis, and nerve root injury EXTREMELY rare.
Which gets more adjacent level degeneration/disease in the cervical spine? ACDF or non-fusion procedure?
Cho JAAOS 2013
Similar rates of adjacent level degen/disease regardless of fusion or non-fusion procedure.
No evidence that a fusion procedure leads to adjacent level degen.
Based on Hildebrand study, 1999, who gets more adjacent level disease in the C-spine - single level fusion or multilevel fusion?
Cho JAAOS 2013
Statistically lower rates of adjacent disease in the multilevel fusion (12%) vs 18% for single level fusion
RFs for developing adjacent level disease?
- Preexisting spondylotic change
- Procedures next to C5-6 and C6-7
Risk factors for wrong site spinal surgery.
Emergent surgery Obese patient Hx of prior surgery (altered anatomy) Unfamiliar equipment 2 surgeons involved Multiple procedures during one surgery Misinterpret intraop xray
Indications to operate on discitis
Failure to respond to antibiotics
Progressive neuro deficit
Progressive deformity
Surface landmarks for anterior spine approach
C3 - hyoid bone C4/5 - thyroid cartilage C5 - cricoid cartilage C7 - most prominent L2 Renal artery L4 Aortic bifurcation S1 Iliac bifurcation
Pearls for thoracoabdominal approach
For access to T12 and L1, diaphraghm has to be cut.
Above T12 - principles of thoracotomy
Below L1 - principles of lumbotomy
For T12-L1
Gain access to thoracic cavity posteriorly (cut parietal pleura)
Gain access to retroperitoneum anteriorly (cut three layers of abdominal musculature)
To connect the retroperitoneum to the thoracic cavity, the diaphragm must be cut. Leave 1cm peripheral flap for later repair.
