Biomechanical comparison of laminotomy versus laminectomy- A cadaveric study
Stability of the lumbar spine is attributable to several structures in the functional spinal unit. The association of lumbar spine instability between laminotomy and laminectomy has been clinically studied, but the corresponding in-vitro biomechanical studies are very limited. Using a cadaveric simulation model we compared lumbar spine stability after unilateral laminotomy, bilateral laminotomy and laminectomy in fresh frozen human cadaver models on mechanical loading.
Materials & Methods:
Ten fresh frozen human cadaver lumbar spine specimens were studied. Each specimen was tested intact (Group I), after unilateral laminotomy (Group II), bilateral laminotomy (Group III) and laminectomy (Group IV). Universal testing machine was used to generate physioloical loading in flexion, extension and lateral bending. Intervertebral displacement was measured by extensometer.
Under flexion motion, intervertebral displacement of laminectomy (Group IV) specimens at decompression level L3â€“L4 was statistically greater as compared to intact, unilateral or bilateral laminotomy specimens (p<0.05). No significant difference was found among any of the other movements (p> 0.05).
Unilateral laminotomy and bilateral laminotomy are more stable surgical procedures. Laminectomy causes spinal segmental instability in flexion. Integrity of posterior osteoligamentous complex helps to provide segmental stability of the decompressive spinal unit.