Stenosis means narrowing, and when referenced to the spine means narrowing or constriction of the spinal canal, which contains the spinal cord and nerves. Although the lumbar spine region is more accommodating and forgiving (than the cervical or thoracic regions) of neurologic compression, it is also the most common location of its occurrence. Spinal stenosis is generally sequelae of aging and degenerative arthritis of the spine. As the degenerative process occurs, the ligamentum flavum becomes hypertropic (overgrown) and the facet joints enlarge and develop osteophytes (bone spurs) that encroach into the spinal canal. As the nerve compression worsens, patients often develop pain, numbness, weakness, and/or difficulty walking (neurogenic claudication). Spinal stenosis is increasingly being recognized as a major cause of pain and dysfunction in our society, particularly since the elderly population is growing exponentially. It is expected that by 2030, 20% of the population will be 65 years or older.
The condition of spinal stenosis is extremely common and usually easily diagnosed. It can be complicated when the symptoms or physical findings are atypical. Some patients will complain of isolated "hip pain" or "knee pain," and be evaluated and treated for this rather than a back problem. It is important for the clinician to conduct a thorough history and clinical examination prior to formulating a diagnosis so as not to misdiagnosis this condition. Imaging studies (and occasionally laboratory tests) must be used to clarify the diagnosis.
The treatment of lumbar spinal stenosis often depends on the severity of a patient's symptoms and the severity of neurologic compression. Patients with mild or moderate stenosis may respond very well to conservative treatments. Conservative treatments may consist of oral anti-inflammatory medications and pain medications. Muscle relaxant medications should be used for severe pain and muscle spasms, and only for short duration in elderly patients. Complications secondary to medications are more common in the elderly, and all medications should be closely monitored by the prescribing physician. Physical therapy, manipulation, and modalities may also be utilized, primarily to improve a patient's strength, endurance, and level of function. Epidural steroid injections may provide dramatic improvement of pain symptoms, but only 25% have long-term relief according to a study authored by Surin.
When a patient has severe spinal stenosis and symptomatology, or a patient with mild or moderate stenosis has failed conservative modalities, surgical intervention is considered. Patients noted to have multiple spinal levels involved are indicated for a laminectomy. If a patient only has one or two levels of involvement, then minimally invasive procedures such as a microscopic laminectomy or intra-laminar decompression may be considered. The goals of surgery are to improve a patient's pain and level of function, as well as prevent further deterioration of function and worsening pain. Patients who demonstrate instability or mal-alignment of the spine may also require spinal fusion (mending the spine bones together) in addition to a decompression procedure. There is a high rate of success for patients treated surgically, yet there is a notable increase in morbidity and mortality in elderly patients over 80 years-old, especially those with significant medical problems. A careful preoperative evaluation and delicate perioperative and postoperative management is particularly important in this setting.
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