Significance of Measuring Dimensions of Lumbar Lamina and Spinal Canal – A Cadaveric Study

Introduction: The incidence of lumbar nerve root compression and surgeries for its treatment likelaminectomy, laminotomies are increasing. Similarly, intralaminar screw insertion and use of laminar hooksfor stabilization is also gaining popularity. The dimensions of lumbar lamina are of importance for designingof lumbar spinal implants used. Method: The present study was under taken to measure vertical height oflumbar lamina and width of lumbar vertebral canal in cadavers. Lumbar spine was exposed from posteriormidline approach in 20 formalin preserved cadavers. The dimensions of lumbar lamina L1 to L5 wererecorded with the help of Digital Vernier Caliper after removal of soft tissue from the vertebrae. The datawas analyzed using SPSS software version 23. Result: Range of transverse width of vertebral canal ofL1 and L2 was 14-23 mm. It gradually reduces in L3, L4 and L5 (12-21 mm). There was no significantdifference in width of vertebral canal between Male and female. Mean height of lamina at junction withtransverse process at L2 was (25.7±2.8mm) which reduced from L3, L4 and was lowest in L5 (20.8±2).Mean height of lamina at junction with Spinous process increased from L1 to L2 (27.55±3.3) and decreasedfrom L3, L4 and L5 being smallest (24.3±2.7). The gender, right and left differences for the dimensions oflumbar vertebral lamina were statistically insignificant. In 35 percent cases the spinous processes were fusedwhich was an accidental finding. Conclusion: The data so collected will be of great significance for spinalsurgeons and for designing of implant around this region.