Lumbar spondylosis: Pathogenesis, diagnosis and treatment

Abstract

Described are the basic concepts of diagnosing and surgically treating lumbar spondylosis, a degenerative disease particularly involving the facet joints of the lumbosacral spine. This results in stenotic lesions of the central and nerve root canals that impinge on the cauda equina and lumbosacral roots. The hypertrophied inferior articular facets constrict the central portion of the vertebral canal (central spinal stenosis) and the degenerated thickened yellow ligament usually enhances this stenosis. Intermittent claudication is a typical clinical syndrome. The lumbosacral roots run through the nerve root canal and their entrapment can occur and cause stenosis at two locations: most commonly in a narrow lateral recess, i.e., a lateral or subarticular recess stenosis, and, less frequently, in an exit zone of the nerve root canal between the pedicle and the superior articular process, i.e., a lateral stenosis. Computed tomography (CT) with myelography is a most reliable method to diagnose lumbar spondylosis, since this provides precise information about both the anatomical and pathological status of a bony and/or a soft tissue involvement, and a lateral stenosis associated with herniation of a distant lateral disc cannot be diagnosed unless CT-myelography is used. Magnetic resonance imaging (MRI) provides three-dimensional images of neural tissue entrapment and information on intervertebral disc degeneration. Decompressive treatment can be classified into three basic surgical procedures. A decompressive laminectomy is the choice for central spinal stenosis, whereas a medial facetectomy is used for a lateral recess stenosis (subarticular recess stenosis) and a facetectomy for a lateral stenosis. Since patients often show many clinical signs and symptoms of a cauda equina and/or radicular compression, all three operative procedures are usually variously combined. In view of possible postoperative instability, we do a bilateral partial laminectomy for treating central spinal stenosis, which is a limited interlaminar decompressive procedure that does not require removal of the spinous process, and the supra- and inter-spinous ligament, and posterolateral fusion is usually performed for cases given a facetectomy. Our long postoperative follow-up results have shown a 90% recovery from intermittent claudication and an 89% success rate in relieving leg pain, respectively.