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

Abstract

Introduction: The incidence of lumbar nerve root compression and surgeries for its treatment like
laminectomy, laminotomies are increasing. Similarly, intralaminar screw insertion and use of laminar hooks
for stabilization is also gaining popularity. The dimensions of lumbar lamina are of importance for designing
of lumbar spinal implants used. Method: The present study was under taken to measure vertical height of
lumbar lamina and width of lumbar vertebral canal in cadavers. Lumbar spine was exposed from posterior
midline approach in 20 formalin preserved cadavers. The dimensions of lumbar lamina L1 to L5 were
recorded with the help of Digital Vernier Caliper after removal of soft tissue from the vertebrae. The data
was analyzed using SPSS software version 23. Result: Range of transverse width of vertebral canal of
L1 and L2 was 14-23 mm. It gradually reduces in L3, L4 and L5 (12-21 mm). There was no significant
difference in width of vertebral canal between Male and female. Mean height of lamina at junction with
transverse 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 decreased
from L3, L4 and L5 being smallest (24.3±2.7). The gender, right and left differences for the dimensions of
lumbar vertebral lamina were statistically insignificant. In 35 percent cases the spinous processes were fused
which was an accidental finding. Conclusion: The data so collected will be of great significance for spinal
surgeons and for designing of implant around this region.