Lumbar Spinal Stenosis

Lumbar spinal stenosis (LSS) is a medical condition where the spinal canal narrows, compressing nerves and blood vessels at the lumbar vertebrae. It can also affect the cervical or thoracic regions, known as cervical or thoracic spinal stenosis respectively. LSS can cause low back pain, abnormal sensations, and numbness in the legs, thighs, feet, or buttocks, and may lead to loss of bladder and bowel control.

Signs and Symptoms

LSS often presents with lower extremity pain combined with back pain. Symptoms include pain, weakness, and tingling in the legs, radiating to the feet. Other symptoms include fatigue, heaviness, leg cramps, and bladder issues. Symptoms are typically bilateral but can be unilateral. Neurogenic claudication, worsening with standing or walking and improving with sitting or bending forward, is common.

The initial symptoms usually start with episodes of low back pain, potentially progressing to claudication over months or years. Differentiating between vascular claudication and LSS is challenging, but essential as both conditions can coexist.

Causes

LSS may be congenital or acquired due to degenerative changes. Central stenosis refers to the narrowing of the entire canal, while foraminal stenosis pertains to the narrowing of the foramen where the nerve root exits. Other contributing factors include thickening of the ligamentum flavum, facet hypertrophy, and conditions like degenerative spondylolisthesis and ankylosing spondylitis.

Degenerative Spondylolisthesis

This condition involves the forward displacement of a vertebra, narrowing the spinal canal. It is common in older adults and is often associated with diabetes and post-oophorectomy in women.

Diagnosis

Diagnosis is based on clinical findings, with imaging (CT, MRI) aiding confirmation. The normal lumbar central canal has a midsagittal diameter greater than 13 mm, with stenosis considered when this measurement is 10 mm or less. MRI is the preferred diagnostic tool, revealing degenerative changes and spinal cord damage.

Bicycle Test of Van Gelderen

This test helps differentiate between vascular claudication and LSS. Patients pedalling on a stationary bike will find relief from symptoms while leaning forward if LSS is the cause, unlike vascular claudication.

Treatment

Nonoperative Therapies

Initial treatment is usually conservative, focusing on medications, physiotherapy, and injections. Avoiding stress on the lower back and engaging in a physical-therapy programme for core strengthening and aerobic conditioning are common recommendations.

Medication

Evidence for medical interventions is limited. Injectable calcitonin may offer short-term relief, while epidural blocks can provide transient pain reduction. Nonsteroidal anti-inflammatory drugs, muscle relaxants, and opioids are often used, though their efficacy is unproven.

Surgery

Surgery is considered if symptoms persist after 3–6 months of conservative treatment. Laminectomy is the most effective surgical option, with improvement seen in 60–70% of cases. However, surgical interventions are more costly and risky than medical management.

Prognosis

Most individuals with mild to moderate symptoms do not worsen. Surgical outcomes improve short-term but may decline over time. Factors like depression, cardiovascular disease, and scoliosis negatively affect prognosis, whereas severe stenosis and good overall health predict better outcomes.

Epidemiology

Degenerative changes leading to LSS are common, especially in older adults. Approximately 21% of individuals over 60 have LSS. Men are affected earlier, often due to heavier workloads and higher BMI. Despite increasing diagnosis rates, there is a disproportionate rise in spinal surgeries.

History

LSS was first described in 1900, with clinical recognition attributed to Henk Verbiest in 1954. Initial surgical treatment reports showed high success rates, but later studies highlighted the potential for symptom stability without intervention.

Society and Culture

In the United States, LSS is recognised as a disabling condition under the Social Security Act, particularly when it results in neurogenic claudication and significant mobility impairment.

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Self-assessment MCQs (single best answer)

What is Lumbar Spinal Stenosis (LSS)?

Which symptom is commonly associated with Lumbar Spinal Stenosis?

What imaging technique is preferred for diagnosing Lumbar Spinal Stenosis?

Which of the following is a non-operative therapy for Lumbar Spinal Stenosis?

What is degenerative spondylolisthesis?

Which test helps differentiate between vascular claudication and Lumbar Spinal Stenosis?

What is the common surgical treatment for Lumbar Spinal Stenosis?

Which condition is often associated with Lumbar Spinal Stenosis in older adults?

What is the typical age group affected by Lumbar Spinal Stenosis?

What is the prognosis for individuals with mild to moderate Lumbar Spinal Stenosis?