Abstract
Background: Spinal fusion for degenerative disc disease remains a controversial issue due to adjacent segment disease. Several alternatives have been evaluated; including Dynamic Neutralisation System for Spine and artificial disc arthroplasty. In our cohort study, we are highlighting advantages of DYNESYS over TDA and fusion as being a simple and reversible procedure if removal of implants is necessary.
Material & Methods: Prospective cohort study on 415 patients underwent DYNESYS. The implant has to be removed in 43 patients. Patients were evaluated preoperatively using Oswestry Disability Index, SF 36 and Visual Analogue Scores together with plain imaging and MRI scanning. Preoperative discography was performed in 81% of patients. Questionnaires were evaluated on subsequent follow up at 3/12, 6/12 then at annual intervals.
Results: Average treatment period was 26 months with a range from 3/12 to 60/12. The main reason for DYNE-SYS removal was screws’ failure or loosening followed by infections. The implant was used to treat single disc space in 20.9%, two spaces in 67.4% and three disc spaces in 9.3%. 81% of the screws were not Hydroxy Appetite coated. No loosening was detected among HA coated screws.
Outcome assessment revealed significant improvement in SF36 even after removal of stabilising system while no worsening of ODI or VAS in comparison with preoperative status.
Conclusions: DYNESYS can maintain disc height and restricts movements exceeding physiological limits. HA coated screws have superior biomechanical characteristics in preventing screw loosening and subsequent spinal spasms. If necessary, removal of implants is a simple procedure.
Correspondence should be addressed to Mr Carlos A. Wigderowitz, Senior Lecturer, University Dept of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Dundee DD1 9SY
