Biomechanical And Clinical Evaluation Of Lumbar Lanminotomy And Replantation

Object: To investigate whether LLR and LIHLR can provide more stability than traditional total laminectomy and the clinical results of LLR and LIHLR.Materials and Methods: 1. Biomechanical study: 40 New Zealand white rabbits were divided into 4 groups at random. Group A₁ was performed lumbar laminotomy and replantation(LLR); Group A₂ accepted lumbar inter hemi-laminotomy and replantation (LIHLR); Group B accepted total laminectomy(TL) ; Group C was control group. 2 months after operation all the rabbits were scarified and the vertebrae were studied in biomechanical methods. Axial compression, flexion, extension, lateral bending and torsion loading within physiological range were applied to each specimen. All the data of loading including loading-displacement, point of maximum bending and bending strength were recorded for statistical analysis. 2. Clinical study: In this study, 821 patients underwent LLR or LIHLR. Clinical results of 434 patients who were followed up were reported (174 LLR cases, 260 LIHLR cases). This group included 232 male and 202 female and age range was 38 to 75 years (mean 53. 2y).Results: The biomechanical result demonstrated that axial displacement of LLR decreased by 36% -44.5% compared with total laminectomy (p<0. 01) , but increased 45.5%—62.7% with control group(p<0.01) .The same phenomenon was observed in LIHLR, axial displacement decreased 41. 3%-55. 5% compared with total laminectomy(p<0. 01) .while 8. 3%¹9. 9% (p<0. 05) compared with LLR. There weresignificant statistical differences in axial compression, flexion, extension lateral bending, torsion loading, point of maximum bending and bending strength between LLR/LIHLR and total laminectomy. But LLR/LIHLR has no statistical differences compared with control group in point of bending and bending strength.The clinical results: the operation time was 45 92min for LLR/LIHLR (mean 58 min) . The mean blood loss through the procedure was 158ml. No major operation-related complications were observed. The mean ADL scale of JOA was 24. 3 and the recovery ratio was 93%.Conclusion: LLR/LIHLR can preserve more spinal stability in flexion, extension and lateral bending movements than total laminectomy. LIHLR has advantage over LLR in axial movement. Compared with total laminectomy LLR/LIHLR has greater advantages in axial, flexion, extension, lateral bending and torsion movements, as well as point of bending and bending strength. LLR/LIHLR can expose spinal canal and facilitate complete canal decompression. Meanwhile, with the replantation of lamina, it can preserve posterior structure and mechanical stability and prevent the dura sac adhesion with the soft tissue above it.