Analysis of Lumbar Canal dimensions using CT Morphometry in south Indian population – A Cross sectional study

Abstract

Introduction: Lower back pain is increasingly common among younger individuals, likely due to lifestyle changes. Radiological evaluations are essential for diagnosing spine pathologies, including lumbar spondylosis, lumbar disc disease, and spinal canal stenosis. Lumbar canal stenosis is characterized by reduced antero-posterior and lateral dimensions of the spinal canal. CT scans are preferred for studying vertebral morphometry.

Objectives: This study aims to establish normative lumbar canal dimensions for the South Indian population, considering age and sex demographics, to aid in clinical diagnosis and management.

Methods: This cross-sectional study included 247 patients aged 20-40 years, conducted at Department of Orthopedics in SRM Medical College and Hospital from September 2023 to February 2024. CT scans (64-slice and 128-slice) were used to measure lumbar vertebral dimensions including upper and lower vertebral width, upper and lower vertebral depth, and intervertebral disc height and Canal dimensions including spinal canal AP diameter, intervertebral foramen diameter, and inter-facet distance. Data was analyzed using SPSS version 25.0, comparing dimensions across genders and age groups to identify significant differences.

Results: The study included 247 patients, with 157 males (63.6%) and 90 females (36.4%). The highest number of patients were in the 36-40 age group (76 patients), followed by those under 25 years (70 patients). The lowest number of patients were in the 25-30 age group (46 patients). Vertebral dimensions showed that the upper vertebral width (UVW) increased from L1 to L5 in both genders, with minimum UVW at L1 and maximum at L5. Lower vertebral width (LVW) increased from L1 to L4, then slightly decreased at L5. Upper vertebral depth (UVD) and lower vertebral depth (LVD) both increased from L1 to L5, with UVD decreasing in the 36-40 age group. Intervertebral disc height (IVDH) increased from L1 to L4, then decreased at L5, showing an increase with age. Canal dimensions revealed that spinal canal AP diameter (SCD) decreased from L1 to L3, then increased from L4 to L5, with SCD decreasing with age. Intervertebral foramen diameter (IVFD) increased from L1 to L3, then decreased from L3 to L5, showing a decrease with age, then an increase in the 36-40 age group. Inter-facet diameter (IFD) increased from L1 to L5, with IFD decreasing in the 36-40 age group.

Conclusions: In our study of 247 South Indian patients, we measured vertebral and canal dimensions from L1 to L5 using CT morphometry. Significant differences were found across gender and age groups. Vertebral dimensions generally increased from L1 to L5 and from under 25 to 31-35 years, but decreased in the 36-40 age group, except for UVW. Spinal canal AP diameters decreased from L1 to L3, then increased from L4 to L5, with variations across age groups. Intervertebral foramen and inter-facet diameters showed similar trends. Dimensions were higher in males, and notable differences were observed in the 31-40 age group, indicating early degenerative changes. This data provides baseline normative values for diagnosing lower back pain and lumbar canal stenosis in the South Indian population.