Tandem stenosis: a cadaveric study in osseous morphology

BackgroundTandem stenosis is the occurrence of concurrent cervical and lumbar stenosis. The prevalence has been estimated to be from 5% to 25%. Symptomatic tandem stenosis can present with a confusing scenario of both neurogenic claudication and myelopathy symptoms.PurposeThe purpose of this study was to determine 1) the prevalence of anatomic tandem stenosis in a cadaveric population, 2) if there was an associative relationship between lumbar and cervical stenosis, and 3) the positive predictive values of stenosis in one area for stenosis in the other.Study designWe obtained 440 skeletally mature skeletons and examined the cervical and lumbar spines from the Hamann Todd Collection in the Cleveland Museum of Natural History.MethodsFor the cervical spine, we measured the mid-sagittal canal diameter using digital calipers for every level from C3 through C7. The minimum full central sagittal diameter was recorded for each level. For the lumbar spine, we measured the minimum full mid-sagittal canal diameter for every level from L1 through L5, using digital calipers. Stenosis was defined as a mid-sagittal canal diameter of less than 12 mm at at least one level. After analysis of this data, a second analysis was performed after correcting the data for contemporary body size and radiographic manifestation.ResultsThe prevalence of tandem stenosis ranged from 0.9% to 5.4% in this population. The association of cervical and lumbar stenosis was found to be statistically significant (p<.05). Stenosis in one part of the spine positively predicts for stenosis in the other area of the spine 15.3% to 32.4% of the time.ConclusionTandem stenosis should be considered when evaluating a patient with mixed claudication and myeloradiculopathy symptoms.