Spine Flashcards
Cord compromise as canal diameter decreases….what value for SAC?
Cord compromise as canal diameter decreases
Congenital versus acquired (traumatic, degenerative)
Diameter measured on plain lateral radiograph
from posterior aspect of vertebral body to
spinolaminar line (Fig. 8.5); diameter less than
14 mm is cause for concern.
Normal 14 mm or greater
Relative stenosis: less than 14 mm (10–13 mm)
Absolute stenosis: less than 10 mm
Pavlov (Torg) ratio (canal/vertebral body width)
Clinical significance debated
Normal ratio should be 1.0.
Ratio less than 0.8 considered abnormal and may
be a risk factor for later neurologic involvement
(debated).
Ranawat classification for neuro impairment with RA?
Indications for surgery in subaxial subluxation in RA?
Occurs in 20% of cases of RA
Seen in combination with upper cervical spine
instability
Pathoanatomy
Pannus formation in uncovertebral joints (joints of
Luschka) and facet joints. Subluxation may occur at
multiple levels.
Radiographic markers of instability
Subaxial subluxation of greater than 4 mm or
more than 20% of the body is indicative of cord
compression.
A cervical height index (cervical body height/
width) of less than 2.00 approaches 100%
sensitivity and specificity in predicting
neurologic compromise.
Surgical indications
Intractable pain
Progressive neurologic compromise, cervical
myelopathy
Mechanical instability—subluxation greater than 4 mm
Most reproducible line for AA invagination?
Also known as cranial settling, basilar invagination,
cranial invagination, and other names.
Second most common manifestation of RA in
cervical spine
Occurs in 40% of patients with RA
Results in cranial migration of the dens from
erosion and bone loss between the occiput and
C1–2
Often seen in combination with fixed atlantoaxial
subluxation
Measurements are shown in Fig. 8.8.
Landmarks may be difficult to identify.
Ranawat line is most reproducible.
Risk with ACDF in OPLL?
However, OPLL is frequently associated with
dural ossification.
Therefore anterior-based approaches may
be associated with higher incidence of dural
leaks.
Transient quadriplegia: indications to prohibit from participating in contact sports?
Patients with concurrent pathologic conditions,
including instability, HNP, degenerative changes, and
symptoms that last more than 36 hours, should be
prohibited from participating in contact sports.
Define absolute stenosis in spine?
Absolute stenosis is defined as a cross-sectional
area of less than 100 mm2 or less than 10 mm
of anteroposterior diameter as seen on CT cross
section.
What did the SPORT trial show? (Spine Patient Outcome Research Trial)
- The first results were from the Intervertebral Disc Herniation trial. Full papers can be accessed here, but in summary, the study found that while both groups improved substantially after treatment, the improvement from standard surgery, a procedure called “disectomy”, was more rapid. Patients who had surgery also reported better results in physical function and satisfaction one and two years after the operation.
- The second results are from the trial for Degenerative Spondylolisthesis. The full paper can be accessed here. In summary, the study found that patients with spinal stenosis accompanied by degenerative spondylolisthesis who were treated surgically showed substantially greater improvement in pain and function through 2 years follow-up compared to patients treated nonsurgically. Because patients in the randomized cohort “crossed over” either from the non-operative arm to have surgery or from the surgery arm to remain non-operative, the analyses were non-randomized, as-treated comparisons with careful control for potentially confounding baseline factors.
- The third results are from the trial for Spinal Stenosis. The full paper can be accessed here. In summary, the study found that patients with spinal stenosis who were treated surgically showed significantly greater improvement in pain, function and disability through 2 years follow-up compared to patients treated nonsurgically. Because patients in the randomized cohort “crossed over” either from the non-operative arm to have surgery or from the surgery arm to remain non-operative, the analyses were non-randomized, as-treated comparisons with careful control for potentially confounding baseline factors.
- Analyses of the 4-year follow-up data for each of the three cohorts, Intervertebral Disc Herniation, Spinal Stenosis, and Degenerative Spondylolisthesis, demonstrated that the gains the surgical patients had made were maintained at four years.
Epidemiology of spondylolisthesis
Usually at L5–S1 and typically grade II
Occurs most often in whites, boys, and children who
participate in hyperextension activities
Remarkably common in some Eskimo tribes (>50%)
Timing of decompression of cauda equina syndrome?
Although the prognosis for recovery is guarded
in most cases, surgical decompression within the
first 48 hours has been reported to lead to best
outcomes.
In adult scoliosis, what is a strong indicator of disability?
Sagittal plane imbalance is a strong predictor of
disability.
Success of preventing vertebral compression # on bisphosphonate?
Prevention of compression fractures has been
successful with bisphosphonate treatment, with 65%
decrease in vertebral fractures at 1 year and 40% at
3 years.
Location of tumors in the spine? Posterior? Vertebral body (anterior)?
Tumors of the vertebral body
Histiocytosis X
Giant cell tumor
Chordoma
Osteosarcoma
Hemangioma
Metastatic disease
Marrow cell tumors
Tumors of the posterior elements
Aneurysmal bone cysts
Osteoblastoma
Osteoid osteoma
MRI + gadolinium in spine infection? Why?
MRI—modality of choice; supplementation
with gadolinium allows differentiation between
epidural abscess and CSF.
Abscess and CSF have high signal intensity on T2-
weighted images.
Gadolinium enhances the pus on T1-weighted
images, whereas CSF remains low signal.
How can you diff. Between pyogenic vs TB infection in spine?
preservation of the disc distinguishes
tuberculosis from pyogenic infection.
Define Neurologic Level of Injury
