Biomechanical comparison of lumbar spine stability after laminectomy versus bilateral laminotomy: An experimental study in porcine model

Abstract

Background: Rationality of the lumbar spine is inferable to many structures in the practical spinal unit. The alliance of lumbar spine unreliability between laminectomy and laminotomy had been clinically studied, but the corresponding in vitro biomechanical studies are very limited. We explored the hypothesis that the uprightness of the posterior complication plays a vital role on the post-operative spinal rationality in decompressive surgery. Methods: Twenty porcine lumbar spine samples had been studied. Each sample was tested as a whole & after two decompression mechanism. All posterior elements were upheld in Group I (Intact). In Group II (Bilateral laminotomy), the subservient margin of the L4 lamina and predominent margin of the L5 lamina were detached, however the L4 and L5 supraspinous ligament was upheld. Fenestrations design was made on either side. In Group III (Laminectomy) lamina and the spinous activities of lower L4 & upper L5 were detached. Ligamentum flavum & supraspinous ligaments of L4 and L5 were detached. Hydraulic machine for testing was used for the generation of an increasing moment up-to 9000 N-mm in bending of limb and extension. Intervertebral movement at the decompressive level L4 and L5 was evaluated by Extensometer. Results: In extension motion, intervertebral movement between the specimen in complete form and at two dissimilar decompression levels did not remarkably differ (P>0.05). However, In flexion motion, intervertebral movement of laminectomy specimens at the decompression level L4 and L5 was significantly more than in intact or the bilateral laminotomy specimens (P=0.392 and P = 0.0001, P =0.00001). No significance difference was established between intact and the bilateral laminotomy groups (P>0.05). Conclusion: In this experimental study we concluded that Bilateral laminotomy is a more stable surgical procedure as compared to laminectomy in the decompressive surgery of lumbar spine.