Lumbar Spinal
Stenosis
Diagnosis and Management:
A 30 year legend
Philip R. Weinstein, MD
UCSF Dept. of Neurosurgery
San Francisco, California
My Legends
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Brain WR, Wilkinson M, eds.
Cervical Spondylosis and other
Disorders of the Cervical Spine,
Phila. Saunders, 1967
Wilson, CB: Significance of the
small Lumbar Spinal Canal:
Cauda Equina Compression
Syndromes due to Spondylosis.
III. Intermittent Claudication
J
Neurosurg 31 :499, 1969
Classic case: 74 yo male; postural + ambulation
claudication, bilat. footdrop, calf/thigh atrophy,
incontinence
Why so mysterious?
• Lumbar spondylostenosis, one of the most common
neuro-spinal disorders, was not regularly recognized
and treated until 1960. The diagnosis was not
considered as an alternative to disc, infection or
tumor because:
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Stenosis not described/identified
Spondylosis not appreciated/visualized
Postural radiculopathy not understood
Atypical leg pain not interpreted
Neurogenic claudication not defined/explained
Cauda equina syndrome not diagnosed
Role of associated LBP/deformity not appreciated
Why has treatment been
unsuccessful (20-40%)?
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Clinical history/diagnosis not appreciated
Anatomy/imaging misinterpreted
Surgical plan incomplete or excessive
Surgical decompression inadequate
Fusion/fixation omitted/incomplete
Post-operative instability; ASD
Neuropathic radiculopathy
Progressive disc/facet DJD, spondy, scolio
Recurrent/progressive stenosis
Co-morbidities
Books on Lumbar Stenosis
• Neurogenic Intermittent Claudication, Verbiest H,
1976, Elsevier
• Lumbar Spondylosis, Weinstein P, et al,
1977, Year Book Medical
• Cheirolumbar Dysostosis,
Wachenheim A, et al, 1980, Springer
• Lumbar Spinal Stenosis,
Postacchini F, et al, 1989, Springer
• Lumbar Spinal Stenosis, Andersson GBJ,
et al, 1992, Mosby-Year Book
• Lumbar Spinal Stenosis, Gunzberg R, et al,
2000, Lippincott-Williams&Wilkins
Evolution of a Concept: 1911-’25-’60
Spondylotic Caudal Radiculopathy
(SCR)
• Bailey P, Casamajor L,
Osteoarthritis of the Spine as
a Cause of Compression of
the Spinal cord and its
roots: With report of five
cases,
J. Nerv. and
Mental Dis. 38:588, 1911
• Parker JL, Adson AW,
Compression of the Spinal
Cord and its roots and
hypertrophic Osteoarthritis,
Surg. Gynec. Obstet. 41:1,
1925
Pioneering Intra-operative Measurements:
Define the Syndrome
Confirm the Diagnosis
• Verbiest H, Further
experiences on the
Pathological
influence of a
Developmental
narrowness of the
bony Lumbar
Vertebral canal,
J. Bone Joint Surg.
37B:576, 1955
Developmental Variations/Stenosis
Documented
in Normal Sized Cadavers
• Epstein BS, Epstein
JA, Lavine L, The
Effect of Anatomic
variations of the
Lumbar vertebra and
Spinal canal on Cauda
equina nerve root
syndromes, Am. J.
Roentgenol. Radium
Ther. Nucl. Med.
91:105, 1964
Vertebral Embryology
• Unique paired growth centers for neural arch;
vertebral body centers unite at 9 weeks
• Premature arrest only dorsally in LS;
both arch and body in dwarfism
• Conus reaches L2; 22 weeks gestation
• Most rapid canal growth; 18-36 weeks
• L3-4 canal 80% at birth; 100%-1year; stops
• L5 canal 50% at birth; 100%-5years
• Canal deficiency: birth age/weight, mater. age
• L5 trefoil canal: 15-25%
Papp T, et al, JBJS 1995, 77B:469-472
Angevine JB, Clin. NS 1973, 20:95-113
Dwarfism
Familial Cases
Developmental non-dwarf
(2 brothers and a sister)
Postacchini F, et al, JBJS 67A:321, 1985
Incidence of Lumbar Stenosis
in radiculopathy cases
• Primary stenosis
– 2%
• Primary disc
– 31%
• Primary degenerative
– 28%
• Combined
– 39%
N=227
Paine K, Haung P, Lumbar Disc Syndrome JNS 37:75, 1972
Imaging Pearls for the
Diagnostic Necklace
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Thin section axials; no skipped levels
Compare disc vs mid-body sections
View images; beware report omissions/LRS
Sagittals for foraminal height/lat. osteophytes
Sagittals for disc height, spondylolisthesis
Coronals for scoliosis/foramen stenosis
Add CT to MRI for bone detail/facet tropism
CT myelo for postop cases/instrumented fusions
3D CT to rule out pseudarthrosis
IV contrast CT for foraminal root constriction Radiculogram for
foraminal fibrosis (TFESI)
• Flexion-extension MRI for borderline cases
• Intraop fluoro-CT useful for complex stenosis/deformity
Quantification of stenosis
correlates with symptoms
• Mean L4-5 canal area
by CTM in extension in
normals = 145mm2
(range 86-230)
• Myelographic block
occurs = 40mm2
• Transverse canal
diameter below 11mm
is symptomatic
• Lateral recess height
2-4mm is symptomatic
Wilmink JT et al, Neuroradiology,
1988,3:5476-550
Wilmink JT, AJNR,
1989,26:173-181
Radiographic-Clinical Correlation:
Limitations of Measurements
• Asymptomatic abnormalities
seen
• Magnification is variable
• Imaging window, slice
thickness, scan angle, alter
bone/soft tissue
measurements
• Flex-ext. changes
relationships
• Ca on MR; CSF on CT not
well visualized
Mechanisms of neurogenic claudication:
compression, ischemia or both
• 83yo male with L4-5
spondy II and stenosis
5yr. hx of leg pain
during 1block walk
relieved by standing
• At autopsy: radicular
arteries straightened
veins compressed,
neuronal loss, empty
axons, demyelinization,
arachnoid fibrosis,
adjacent AV coilinganastomosis
Watanabe R, Parke W, JNS 64:64-70, 1986
Problems in Patient Selection
and Surgical Planning
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Patient age/co-morbidities
Previous surgery
Unilateral or bilateral decompression
“Asymptomatic” levels
MIS vs open
Disc “herniation”
Disc collapse/foramen stenosis
Spondylolisthesis/scoliosis/kyphosis
“Back pain” without instability
(arthrogenic vs
radicular)
• Fusion: instrumented/PSF vs interbody fusion
What do Evidence-based
Guidelines Tell Us?
• Surgery resulted in better improvement in pain and
function than non-operative rx for stenosis/deg.
spondy @ 2yrs. 17% crossover to surg.
Weinstein JN, (SPORT STUDY) NEJM, 2007;356(22):2257-70
• Surgery better for leg pain and back related function
but equal to non-op rx for pt. satisfaction, back pain
and primary sx relief @8-10yrs. 39% non-ops had
surg.
23% reops.
Atlas SJ, (MAINE STUDY) Spine, 2005;30(8):936-43
Clinical Trial Results
• Unilat Laminotomy for Bilateral
Microdecompr: 520 levels/374pts
• 88% improved VAS/Prolo scale 5yr f/u
0.8% instability: none reoperated
Costa F etal.
JNS-Spine 2007;7(6):579-586