Why people with a narrowed spine often feel better leaning forward
Spinal stenosis squeezes the nerves running through the backbone, and a telltale sign is that symptoms ease when a person bends forward, as over a shopping trolley. Up to 8 percent of people have it, mostly over 50, and traces of the condition reach back to ancient Egypt.
The spine's central canal and the side openings where nerves exit can narrow for many reasons. Ligaments thicken, bone spurs grow inward, discs bulge, a vertebra can slide forward on its neighbour, and fractures from osteoporosis or injury can intrude. Arthritis, tumours, Paget's disease and the genetic condition achondroplasia are other causes. Men and women are affected equally, and the first modern description came from Antoine Portal in 1803.
Location changes everything. The lower back is the most common site, followed by the neck, with the mid-back rarely involved. In the lumbar spine the cord has already ended, so only a bundle of nerve roots called the cauda equina is at risk, producing sciatica-like tingling and weakness down the legs. A classic pattern is neurogenic claudication: leg heaviness and numbness brought on by walking or standing, which fades when sitting or bending, because arching the spine narrows the space further and flexing widens it.
Narrowing in the neck is potentially more serious, because the spinal cord itself can be pinched. That can cause myelopathy, with numb, clumsy hands, poor balance, loss of bladder or bowel control and, at worst, paralysis. People with a narrowed cervical canal also face a higher risk of acute cord injury in accidents.
Diagnosis rests mainly on the patient's history and examination, with MRI now the most used scan because it shows nerves, muscles and ligaments that X-rays miss; CT myelography, using dye in the spinal fluid, helps when MRI is unsuitable, for example with a pacemaker. Options range from medication and exercise to decompressive surgery, but overall evidence is inconclusive on whether surgery beats non-surgical care for the lower back. One small randomised trial of 60 patients found two endoscopic keyhole techniques gave similar results, with good-to-excellent outcomes in about 90 percent of each group.
Source: Spinal stenosis
