Spinal Stenosis: Diagnosis and Treatment
Spinal stenosis is a narrowing of the spinal canal that may result in bony constriction of the cauda equina and the emerging nerve roots, causing neurogenic claudication and radicular symptoms. 1
Definition and Pathophysiology
Spinal stenosis refers to the narrowing of the spinal canal or neural foramina by a combination of bone and soft tissues, which leads to mechanical compression of spinal nerve roots or the dural sac 2, 3. This condition most commonly affects the lumbar spine, followed by the cervical spine, with thoracic involvement being rare 2.
The narrowing can be:
- Congenital: Present from birth
- Acquired: More common and typically results from:
- Degenerative changes (most common)
- Endocrinopathies (Cushing disease, acromegaly)
- Calcium metabolism disorders (hypoparathyroidism, Paget disease)
- Inflammatory diseases (rheumatoid arthritis)
- Infectious diseases 2
A key component in lumbar spinal stenosis is often hypertrophy of the ligamentum flavum, which contributes significantly to canal narrowing 4.
Clinical Presentation
Symptoms
- Neurogenic claudication: Leg pain (and occasionally weakness) on walking or standing, relieved by sitting or spinal flexion 1
- Radicular pain or atypical leg pain
- Back pain
- Weakness
- Sensory changes
- Gait disturbances
- In severe cases: bowel or bladder dysfunction 3
Key Clinical Features
- Pain relief when sitting or leaning forward (spinal flexion)
- Worsening of symptoms with walking or standing (spinal extension)
- Bilateral symptoms (often)
- Gradual onset and progression of symptoms
Diagnosis
Diagnosis of spinal stenosis relies on both clinical presentation and imaging findings:
Clinical Examination
- Physical examination may be normal in lumbar spinal stenosis 2
- Changing symptoms on downhill treadmill testing (positive likelihood ratio of 3.1) 1
- Age older than 65 years (positive likelihood ratio of 2.5) 1
- Pain relieved by sitting (variable usefulness) 1
- Pseudoclaudication (positive likelihood ratio of 1.2) 1
- Radiating leg pain (positive likelihood ratio of 2.2) 1
Imaging Studies
- MRI: Preferred imaging modality that can visualize the spinal canal, neural elements, and soft tissues 1, 2
- CT: Alternative when MRI is contraindicated; better for bony detail 1, 3
- Plain radiography: Limited value as it cannot visualize discs or accurately evaluate the degree of spinal stenosis 1, 5
Ancillary Tests
- Electromyography (EMG) and evoked potentials have limited diagnostic value 5
- May be useful to establish differential diagnoses, particularly vascular claudication 2
Treatment Algorithm
1. Conservative Management (First-line for mild to moderate symptoms)
- Patient education about the condition and prognosis
- Pain medications (NSAIDs, analgesics)
- Delordosing physiotherapy (exercises that promote spinal flexion) 6
- Epidural steroid injections 6
2. Surgical Management
Indications for surgery:
- Progressive, intolerable symptoms despite 3-6 months of conservative treatment 6
- Clinically relevant motor deficits (absolute indication) 6
- Cauda equina syndrome (absolute indication) 6
Surgical options:
- Decompression procedures based on anatomical level and type of narrowing:
- Laminectomy
- Foraminotomy
- Discectomy
- Corporectomy 2
- Additional instrumentation if spinal stability or sagittal balance is compromised 2
- Minimally invasive procedures such as mild (minimally invasive lumbar decompression) for ligamentum flavum hypertrophy 4
Evidence for Treatment Effectiveness
- Class 1b evidence supports that surgery provides more benefit for lumbar stenosis at least in the short term compared to conservative treatment 2
- Randomized, prospective studies provide class I-II evidence that decompressive surgery leads to a more rapid and profound decline of symptoms than conservative therapy 6
- For cervical spine stenosis, the main objective of surgery is to halt disease progression 2
Important Considerations and Pitfalls
Differential diagnosis: Vascular claudication can mimic neurogenic claudication but typically improves with rest regardless of position, while neurogenic claudication improves with sitting or forward flexion.
Imaging findings vs. clinical symptoms: Radiographic stenosis is common in asymptomatic elderly individuals. Only when symptoms of neurogenic claudication or myelopathy are present should a diagnosis of symptomatic spinal stenosis be made 2.
Surgical timing: Consider that trials of surgery for nonspecific low back pain included only patients with at least 1 year of symptoms 1.
Comorbidities: Assess surgical risks based on the patient's comorbid conditions before recommending invasive interventions 1.
Psychosocial factors: These can influence outcomes and should be considered when developing a treatment plan 1.