Computed-tomography assessment of the lumbar spine body/canal index and review of the literature

Abstract

Lumbar spinal stenosis (LSS) involves narrowing of the lumbar spinal space due to various factors. Torg-Pavlov Index measures predict LSS. The objective was to define the mean characteristics of the lumbar spine body/canal index in a Hispanic population stratified by age and sex. A retrospective, observational, transverse, and descriptive study was performed. Imaging studies included consecutive bone window full abdominal CT scans, in adult patients (≥18 years), without evidence of bone disease, musculoskeletal pathology, or traumatic event and a fully visible lumbar spine (L1-L5). The anteroposterior diameter (APD) and midsagittal diameter (MSD) of each vertebral level were measured using the Carestream image reformatting program at each lumbar vertebral level from L1 to L5 of the CT scan. A total of 400 CTs of subjects with a mean age of 47.7±14.8 (range 18-80 years) were evaluated, of which 59.3% (n 237/400) were women. The presence of a ≤0.5 body/canal index was 31.6% (n 126). The MSD/APD lumbar index did not differ significantly between age groups in any of the vertebrae. However, there was a tendency to decrease with age. An mean index higher than 0.5 was the mean found in the patients evaluated where there was no previous data of spinal cord involvement. This study provides an accurate description of the normal morphometric parameters of the lumbar body/canal ratio in a Mexican population to assess clinical scenarios of lumbar spinal stenosis. Few studies evaluate the use of cut-off points to define an LSS.