Artikel
Biological sealing of annulus fibrosus defects with a polymer-based implant in an ovine model
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Veröffentlicht: | 16. September 2010 |
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Gliederung
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Objective: Spinal surgery procedures for disc herniation can be complicated by two major problems: (1) re-herniation through the annulus fibrosus defect and (2) painful degeneration of the spinal segment. Therefore, we examined a textile absorbable polymer-based biomaterial for its utility to seal annulus fibrosus defects aiming for (a) preventing re-herniation and (b) providing a containment strategy for potential nucleus implants.
Methods: Via a left retroperitoneal approach the discs L3/4 and L4/5 of 20 adult merino sheep were approached. A standardized box defect was applied to the annulus of each disc, followed by randomized insertion of the annulus implant in one of the defects. Explantation of the spinal segments was conducted after 2, 6 and 12 weeks. Evaluation of the discs were performed by magnetic resonance imaging, histological analysis and pressure-volume testing.
Results: At all time points, no implant dislocations were detected with mri. Contrary to the control defect, histological analysis of the annulus implants showed proper nucleus containment. In addition, considerable cell in-growth and matrix assembling in the biomaterial was observed. However, a smear effect was noticed at the outer absorbable layers of the implant. Pressure-volume testing showed an increasing pressure resistance with time, but after 12 weeks no advantage in comparison to the control defect could be noticed.
Conclusions: The presented annulus sealing system showed promising results with regard to biocompatibility and mechanical function in an ovine model. Optimization of the absorbable component and design of an adequate application and fixation system, however, are mandatory before clinical application.