What are the symptoms and findings of lumbar spinal stenosis?

Symptoms and Findings of Lumbar Spinal Stenosis

Lumbar spinal stenosis is characterized primarily by neurogenic claudication, with activity-related low back and leg pain that worsens with prolonged standing or ambulation, compromising patients' quality of life. The hallmark symptom of lumbar spinal stenosis is pain that worsens with lumbar extension (standing/walking) and improves with lumbar flexion (sitting/bending forward). 1, 2, 3

Cardinal Symptoms

• Pain radiating to the buttocks and lower extremities bilaterally, typically described as burning or cramping in nature 3
• Neurogenic claudication: activity-related pain that worsens with prolonged standing or walking 1, 2
• Pain relief with sitting or forward bending (lumbar flexion) 2, 3
• Worsening of symptoms with lumbar extension (standing or walking) 2, 3
• Progressive limitation in walking distance and standing tolerance 1, 2

Physical Examination Findings

• Positive straight leg raise (SLR) test: 91% sensitivity but only 26% specificity for diagnosing nerve root compression 4, 5
• Positive crossed SLR test (pain produced when raising the unaffected leg): lower sensitivity (29%) but higher specificity (88%) 4, 5
• Normal neurological examination at rest in many patients 2
• Possible neurological deficits after walking (provocative testing) 2, 6
• Relief of symptoms with forward flexion of the spine 3, 7

Clinical Course and Progression

• Typically a progressive waxing and waning process that may deteriorate over years 3
• Natural history without intervention: approximately one-third of patients report improvement, 50% report no change, and 10-20% report worsening symptoms over 3 years 2
• More common in older adults, with a mean age of 64 years 3
• Affects approximately 11% of US adults, with prevalence increasing with age 2

Diagnostic Imaging

• MRI is the recommended diagnostic test as it allows cross-sectional measurement of the spinal canal 3
• Radiographic findings should correlate with clinical symptoms for proper diagnosis 2, 6
• Common findings include central canal narrowing, lateral recess stenosis, and/or foraminal narrowing 7

Associated Conditions

• May coexist with spondylolisthesis or spinal instability, which can affect treatment decisions 1
• Can occur with or without spinal deformity 1
• Degenerative changes are common and associated with the natural aging process 1, 7

Differential Diagnosis

• Vascular claudication (differs in that it is not relieved by forward bending) 6
• Lumbar disc herniation (may have more focal neurological deficits) 4, 5
• Peripheral neuropathy (typically symmetrical and not position-dependent) 6

Clinical Pitfalls

• Overreliance on imaging findings without clinical correlation can lead to misdiagnosis, as many asymptomatic individuals have stenosis on imaging 5
• Failure to recognize that symptoms are typically position-dependent (worse with extension, better with flexion) can lead to missed diagnosis 3, 7
• Not distinguishing between neurogenic claudication and vascular claudication can result in inappropriate treatment 6

Lumbar spinal stenosis represents a significant cause of disability in older adults, with characteristic symptoms that correlate with the biomechanical changes occurring during different postures. The diagnosis relies on both clinical presentation and confirmatory imaging findings 2, 3, 7.