الفهرس 
Morphological Anatomy
Anatomy of the Spinal CanalOnly 14 pages are availabe for public view
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Abstract
Degenerative spondylolisthesis, also known as pseudospondylolisthesis, results from severe localized arthritis of the facets (apophyseal joints) of the slipped vertebrae.
The presenting features involve back pain and leg pain. The initial symptom is usually back pain, which may radiate into the buttocks, but patients often complain of a ‘tight’ feeling in the upper thighs. patients often have a gait disturbance, the so-called ‘tight hamstring’ syndrome.
The vertebral slippage may produce compression of the lumbar nerve roots in the neural foramen. This causes sciatica, the symptoms of which may be indistinguishable from those due to disc prolapse. Narrowing of the bony canal may result in clinical symptoms of ‘lumbar canal stenosis’.
Radiological investigations, including plain X-rays, CT scan and MRI, will show the type of spondylolisthesis, the amount of slippage and the associated narrowing of the neural canals. The degree of subluxation is commonly described by the percentage of slip (Taillard method) or assigned a grade (I–IV) based on the number of quarters of the adjacent body spanned by the slip.
In most patients conservative therapy involving short periods of bed rest during exacerbations of discomfort, gentle mobilizing exercises, simple analgesic medication and non-steroidal anti-inflammatory medication will be sufficient. If some pain persists following bed rest a period with a properly fitted lumbar brace may be of value.
Surgery involves either a laminectomy to decompress the neural structures and/or a spinal fusion to prevent instability. A laminectomy decompresses the lumbar theca and nerve roots, usually with satisfactory relief of lower limb symptoms. However, a laminectomy may increase the instability and some surgeons prefer to combine a decompressive laminectomy with a spinal fusion. An intertransverse fusion between the transverse processes has been the traditional method of fusion, but more recently internal pedicle screw fixation and/or interbody ‘cages’ placed in the emptied disc space between the vertebral bodies have become the preferred method.