Lumbar canal stenosis is a narrowing of the spinal canal in the lower back, usually from age-related changes — thickened ligaments, bulging discs and enlarged joints. The narrowed canal compresses the nerves to the legs, classically causing pain, heaviness or tingling in the legs on walking that eases on sitting or bending forward (neurogenic claudication).
Recognising the symptoms
Typical features include leg pain or heaviness that starts after walking a certain distance and improves with sitting or leaning forward (many patients find pushing a trolley easier than walking upright), numbness or tingling in the legs, and gradually shrinking walking distance. Back pain may or may not be prominent.
How stenosis is diagnosed
Diagnosis rests on the clinical story and examination, confirmed by MRI, which shows the levels and severity of canal narrowing. X-rays may be added to check alignment and stability, and to rule out associated spondylolisthesis (vertebral slippage).
Non-surgical treatment first
Mild to moderate stenosis is usually managed conservatively: a structured physiotherapy programme emphasising flexion-based exercises and core strengthening, activity pacing, weight management and appropriate medication. Selected patients may benefit from image-guided injections to control a difficult pain episode.
Surgery for stenosis — decompression
When walking distance keeps falling despite good conservative care, or neurological deficits appear, surgical decompression is considered. Modern options include endoscopic and tubular (muscle-sparing) decompression, which remove the tissue compressing the nerves through small openings. Fusion is added only when there is instability — it is not routine.