Lumbar spinal stenosis

Lumbar spinal stenosis is a condition characterised by narrowing of the spinal canal, most commonly due to degenerative changes. Less common causes include disc herniation, tumour, or congenital canal narrowing.

• Combination of:
• Lower back pain
• Leg pain (often neuropathic)
• Symptoms mimicking claudication (neurogenic claudication)
• Pain is position-dependent:
• Worse with standing and walking
• Relieved by sitting or lumbar flexion
• Patients often find it easier to walk uphill than downhill
• Presence of a typical neurogenic claudication history strongly supports the diagnosis
• Absence of positional leg symptoms makes lumbar spinal stenosis less likely
• Straight leg raise is typically normal in lumbar spinal stenosis.

Pathology

• Degeneration begins in the intervertebral disc:
• Loss of proteoglycans and water content
• Disc bulging and loss of disc height
• Increased load is transferred to posterior elements:
• Facet joint degeneration and hypertrophy
• Osteophyte formation
• Thickening and infolding of the ligamentum flavum
• These changes combine to:
• Circumferential narrowing of the spinal canal

• Compression of the cauda equina nerve roots produces the characteristic symptoms

Diagnosis

• MRI scanning is the investigation of choice
• Demonstrates canal narrowing and neural compression
• Historically, a bicycle test was used:
• Patients with neurogenic claudication could cycle longer than those with true vascular claudication

Treatment

• Conservative management initially:
• Analgesia
• Physiotherapy
• Surgical decompression (e.g. laminectomy) for severe or refractory symptoms