What is the prevalence of spinal stenosis?

Updated: Mar 05, 2018
  • Author: John K Hsiang, MD, PhD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Answer

Approximately 250,000-500,000 US residents have symptoms of spinal stenosis. This represents about 1 per 1000 persons older than 65 years and about 5 of every 1000 persons older than 50 years. About 70 million Americans are older than 50 years, and this number is estimated to grow by 18 million in the next decade alone, suggesting that the prevalence of spinal stenosis will increase. Lumbar spinal stenosis (LSS) remains the leading preoperative diagnosis for adults older than 65 years who undergo spine surgery. The incidence of lateral nerve entrapment is reportedly 8-11%. Some studies implicate lateral recess stenosis as the pain generator for 60% of patients with symptomatology of failed back surgery syndrome.

As many as 35% of persons who are asymptomatic and aged 20-39 years demonstrate disc bulging. CT scanning and MRI studies in patients who are asymptomatic and younger than 40 years demonstrate a 4-28% occurrence of spinal stenosis. Most persons older than 60 years have spinal stenosis to some degree. Because most patients with mild spinal stenosis are asymptomatic, the absolute frequency can only be estimated. [4]

Incidence of foraminal stenosis increases in lower lumbar levels because of increased dorsal root ganglion (DRG) diameter with resulting decreased foramen (ie, nerve root area ratio). Jenis and An cite commonly involved roots as L5 (75%), L4 (15%), L3 (5.3%), and L2 (4%). [21] The lower lumbar levels maintain greater obliquity of nerve root passage, as well as higher incidence of spondylosis and DDD, further predisposing patients to L4 and L5 nerve root impingement.

Cervical stenosis resulting from ossification of the posterior longitudinal ligament is more common among Asians, and LSS occurs most frequently in males. Patients with LSS due to degenerative causes generally are aged at least 50 years; however, LSS may be present at earlier ages in cases of congenital malformations.


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