Post Spinal Stenosis

Spinal stenosis is a term that means narrowing of the spinal canal or the nerve root foramina. It is thus divided into central or lateral stenosis. Central stenosis produces compression of the thecal sac: soft tissue (ligamentum flavum and disc) may contribute as much as 40% to this compression. It is more common in males because their spinal canal is smaller at the L3-L5 level. Lateral stenosis involves impingement of nerve roots lateral to the thecal sac, as they pass through the neural foramina. It is made worse with hypertrophy (overgrowth) of the ligamentum flavum and /or joint capsule. Foraminal stenosis affects the exiting (upper) nerve root. Compression of neural structures produces root ischemia and stenosis also compresses vascu lar supply of nerves so that symptoms are predominately those of neural ischemia. (Inadequate blood supply to nerves). There are many different causes of stenosis, the commonest of which is degenerative changes in the spine. This is also referred to as spondylosis, and tends to occur in the older age groups. However, there are other causes, including congenital or developmental stenosis. This presents at a much earlier age. A further cause is spondylolisthesis, which is slippage of one vertebra on another, usually