What is Spinal Canal Stenosis?
Narrowing of the spinal canal, most commonly in the lumbar spine, that places pressure on the nerves leading to the legs. Produces a characteristic pattern of symptoms known as neurogenic claudication.
Causes
Usually develops as part of the ageing process — thickening of the ligamentum flavum, overgrowth of arthritic facet joints, bone spurs, disc bulges and synovial cysts arising from the facet joints. Spondylolisthesis can contribute to canal and foraminal narrowing.
Symptoms
Pain, burning or aching in the buttocks and legs sciatica brought on by standing or walking symptoms that ease with sitting or leaning forward — many people find pushing a shopping trolley, leaning on a kitchen bench or cycling much easier than walking upright heaviness, weakness or numbness in the legs after walking a distance in more advanced cases, foot drop or persistent numbness…
Diagnosis
History and clinical examination including spinal range of motion, neurological assessment of the legs and walking tolerance. The pattern of symptoms — leg symptoms with walking, relieved by flexion — is highly suggestive.
Imaging
MRI is the investigation of choice, showing the discs, nerves and degree of canal and foraminal narrowing in detail. CT or CT myelography when MRI is contraindicated or for bony detail. Standing X-rays for alignment and instability, including flexion-extension views where instability is suspected.
Treatment
Non-surgical care first physiotherapy stretching, postural work, lumbar and abdominal strengthening, weight loss and general conditioning, simple analgesia paracetamol, short NSAID courses where safe, and CT-guided epidural or selective nerve-root steroid injections. Surgery — most commonly a lumbar laminectomy to remove the bone, thickened ligament and overgrown joint tissue — is considered when non-surgical care has not provided adequate relief and symptoms are limiting walking, standing tolerance, sleep or work.