Biomechanical and in vivo evaluation of experimental closure devices of the annulus fibrosus designed for a goat nucleus replacement model
Open Access
- 17 April 2010
- journal article
- research article
- Published by Springer Science and Business Media LLC in European Spine Journal
- Vol. 19 (8), 1347-1355
- https://doi.org/10.1007/s00586-010-1384-z
Abstract
Promising strategies are being developed to replace or regenerate the herniated nucleus pulposus. However, clinical efficacy of these methods has still to be addressed, and the lack of appropriate annulus closure techniques is increasingly being recognised as a major limiting factor. In the current study, in vitro and in vivo evaluation of novel annulus closure devices (ACDs) was performed. These devices are intended to be used in adjunct to nucleus replacement therapies in an experimental goat study. After a standardised discectomy had been performed, different ACDs were implanted solely or in addition to a collagen nucleus replacement implant. Biomechanical effects and axial failure load were assessed in vitro and followed by in vivo evaluation in a goat model. On axial compression, the average axial failure load for ACDs with four barb rings was significantly higher compared to the implants with five barb rings. The increased range of flexion–extension and latero-flexion observed after discectomy were restored to the normal range after implantation of the implants. Positive findings with the four-ring ACD were confirmed in goats after a follow-up of 2 weeks in vivo. However, after 6 weeks most implants ( n = 16) showed signs of destruction and displacement. Although there seemed to be a tendency towards better results when ACDs were placed in addition to the nucleus replacements, these differences were not statistically significant. Moreover, two endplate reactions extending into the subchondral bone were observed, most likely due to continuous friction between the ACD and the vertebrae. Although current results are encouraging first steps towards the development of an efficient ACD for animal models, further optimisation is necessary. Current results also show that one cannot rely on in vitro biomechanical studies with annulus closure techniques, and these should always be confirmed in vivo in a large animal model.Keywords
This publication has 24 references indexed in Scilit:
- Repair, regenerative and supportive therapies of the annulus fibrosus: achievements and challengesEuropean Spine Journal, 2008
- Rheological characterization of the nucleus pulposus and dense collagen scaffolds intended for functional replacementJournal of Orthopaedic Research, 2008
- Biomechanical evaluation of conventional anulus fibrosus closure methods required for nucleus replacementJournal of Neurosurgery: Spine, 2008
- Recent advances in annular pathobiology provide insights into rim-lesion mediated intervertebral disc degeneration and potential new approaches to annular repair strategiesEuropean Spine Journal, 2008
- Regenerative treatment strategies in spinal surgeryFrontiers in Bioscience-Landmark, 2008
- Is a collagen scaffold for a tissue engineered nucleus replacement capable of restoring disc height and stability in an animal model?European Spine Journal, 2006
- The cost–utility of lumbar disc herniation surgeryEuropean Spine Journal, 2006
- The use of a quadruped as an in vivo model for the study of the spine – biomechanical considerationsEuropean Spine Journal, 2002
- Effect of Anular Repair on the Healing Strength of the Intervertebral DiscSpine, 2000
- Mechanical Response of a Lumbar Motion Segment in Axial Torque Alone and Combined with CompressionSpine, 1986