Understanding Spinal Stenosis
Spinal stenosis is a narrowing of the spinal canal that causes compression of neural structures, resulting in characteristic symptoms of neurogenic claudication (leg pain with walking that improves with sitting or forward flexion) in lumbar stenosis, or myelopathy (gait disturbances, balance problems, fine motor deterioration) in cervical stenosis. 1
Definition and Pathophysiology
Spinal stenosis refers to a clinical syndrome, not just an anatomic finding. 2 The condition involves:
- Narrowing of the spinal canal that results in bony constriction of the cauda equina and emerging nerve roots 1
- Mechanical compression of neural elements or their blood supply, which produces symptoms 2
- Important caveat: Radiographic stenosis does not always equal symptomatic stenosis—anatomic narrowing on imaging is common in asymptomatic older adults 3
The stenosis can occur in different locations:
- Central canal stenosis (compression of the thecal sac) 2
- Lateral recess stenosis (compression of individual nerve roots) 2
- Foraminal stenosis (narrowing of the intervertebral foramen) 2
Clinical Presentation
Lumbar Spinal Stenosis
Neurogenic claudication is the hallmark symptom, characterized by: 1, 3
- Leg pain, weakness, or numbness with walking or standing 3
- Relief with sitting or spinal flexion 1, 3
- Symptoms may include pain in the low back, legs, and buttocks 4
Cervical Spinal Stenosis
Myelopathy is the primary concern, manifesting as: 3, 5
- Gait disturbances and balance problems 3, 5
- Fine motor skill deterioration in the hands 3, 5
- Weakness in upper and/or lower extremities 5
- Radiculopathy with radiating pain, numbness, or tingling in the arms 3, 5
Red Flag Symptoms
Bowel or bladder dysfunction can occur in severe cases, including cauda equina syndrome, which is a medical emergency requiring immediate surgical intervention 1, 3, 5
Diagnostic Approach
MRI is the gold standard for evaluating both osseous structures and neural elements in suspected spinal stenosis 3, 6
Critical imaging findings to assess:
- Cord signal changes on T2-weighted MRI indicate myelopathy and suggest more severe disease warranting prompt attention 3, 5
- Presence of syringomyelia 5, 6
- Degree of canal narrowing and neural compression 7
Functional assessment tools:
- The modified Japanese Orthopaedic Association (mJOA) scale should be used to objectively quantify neurological function, as severity correlates with treatment outcomes 5, 6
Treatment Algorithm
Conservative Management
Conservative management is indicated for mild to moderate symptoms without progressive neurological deficits, including: 3, 8
Important evidence: Exercise-based rehabilitation is equally beneficial for individuals with severe stenosis compared to mild stenosis in the short term, with significant improvements in pain, disability, and strength regardless of stenosis severity 9
For younger patients (<75 years) with mild cervical spondylotic myelopathy (mJOA score >12), conservative management may be considered, but clinical gains are maintained over 3 years in only 70% of cases, requiring close neurological monitoring 5, 6
Surgical Indications
Surgery is indicated for: 3, 5, 6
- Progressive neurological deficits 3, 5, 6
- Cord signal changes or syringomyelia on MRI 3, 5, 6
- Cauda equina syndrome 3, 6
- Severe symptoms unresponsive to conservative treatment after 3-6 months 8
Surgical approach selection:
- Decompression with fusion provides superior long-term outcomes compared to decompression alone for pain relief, functional improvement, and quality of life 3, 5
- Anterior decompression and fusion (ACDF) is appropriate for 1-3 level disease 5
- Posterior laminectomy with fusion is recommended for ≥4-segment disease 5
- Laminectomy alone carries higher reoperation risk due to restenosis, adjacent-level stenosis, and postoperative deformity 3, 5
Expected outcomes: Approximately 97% of patients experience some symptom recovery after surgery 3, 5, 6
Critical Pitfalls to Avoid
Do not assume radiographic stenosis requires treatment—asymptomatic radiographic stenosis does not require intervention 5
Do not delay surgery in the presence of myelopathy with cord signal changes—long periods of severe stenosis can lead to demyelination of white matter and potentially irreversible neurological deficits, with untreated severe cervicomedullary compression carrying a 16% mortality rate 5, 6
Monitor conservatively managed patients closely—the disease course is variable with stepwise decline, and approximately 20-30% of conservatively managed patients ultimately require surgery 6
Recognize that any progression of gait disturbance or development of cord signal changes mandates surgical referral, even in patients initially managed conservatively 5, 6