The Biomechanics And Imageology Preliminary Studies Of Lumbar Intertransverse Absorbable Fusion Cage In The Process Of Biodegradation

Objective:To investigate the biomechanical variation of the lumbar intertransverse absorbable fusion cage in the process of degradation. Methods:Thirty healthy Boer goats of 15±3kg were randomly divided into the experimental and the contrastive group. The PLGA lumbar intertransverse absorbable fusion cage was placed in the L4/5 intertransverse in the experimental group; the same size lilac bone was placed in the same position in the contrastive group. Five goats in each groups were killed at the 1st,3rd, and 6th month after operation, and the all lumbar spine specimens were take out. Simulate the lumbar spine front flexion, back extension, and left/right lateral bending movement in the three-dimensional laser scanner, and the rotation motion in the vertical axis in the mechanical properties of biological materials tester. Five pure torque were loaded by computer, recorded and analyzed the image of lumbar motion, studied the lumbar motion change of surgery segment. Results:At the 1st month, the ROM of front flexion, back extension and left/right bending were comparatively large in the experimental group and the contrastive group, but the left/right rotation were comparatively small in the experimental, there were statistically significant in six movement without left rotation(p<0.05). At the 3rd month, the ROM of front flexion, back extension, right bending and right rotation were decreased with the time lengthen in all sample of the experimental group and the contrastive group, but were increased in left bending and left rotation, there were statistically significant in right bending and right rotation(p<0.05). At the 6th month, the ROM of the six directions was significantly reduced in two groups, there were a large difference on statistics in left and right rotating(p<0.05). Conclusions:1. The ROM of the six directions significantly reduced and the stability of lumbar spine increased, after the PLGA lumbar intertransverse absorbable fusion cage was implanted in goat, showed that the former was better.2. There were stronger mechanical character and compressive strength in the PLGA lumbar intertransverse absorbable fusion cage, and it is favorable for the process of fusion. Objective:To investigate the manifestation of imageology after the lumbar intertransverse absorbable fusion cage was implanted. Methods:Thirty healthy Boer goats of 15±3kg were randomly divided into the experimental and the contrastive group. The PLGA lumbar intertransverse absorbable fusion cage was placed in the L4/5 intertransverse in the experimental group; the same size lilac bone was placed in the same position in the contrastive group. All specimens were accepting X-ray and CT examination at the 1 st,3rd, and 6th month after surgery. The situation of fusion of all specimens was judged by the standard of Baramki and McAfee PC-Zinreich SJ. The final result of judge fusion depends on no less than 2°of Baramki standard, conform no less than 2 conditions of PC-Zinreich SJ standard, and the cage did not displacement. Results:There were no fusion cases in two groups at the 1st month, one fusion case in the experimental group and two in the contrastive group at the 3rd month, three fusion cases in the experimental group and four in the contrastive group at the 6th month by X-ray observed. There were no fusion cases in the experimental group but one fusion case in the contrastive group at the 1 st month, one fusion case in the experimental group and two in the contrastive group at the 3rd month, four fusion cases in the experimental group and five in the contrastive group at the 6th month by CT observed. Conclusion:1. Lucent gap, island-like structure and trabecular bone were the character of the biodegradation and bone fusion in imageology in the 3 to 6 months after the PLGA lumbar intertransverse absorbable fusion cage was implanted in goat.2. The PLGA lumbar intertransverse absorbable fusion cage didn't impact for judge the degree of fusion.