Abstract
Most spinal pedicle fixation systems used in this country are imported and expensive. They mostly employ rigid or semi-rigid screws with a known and significant rate of implant failure. Though they are often designed for ease of insertion, many are difficult to remove.
This study investigated the radiological outcome of a dynamic spinal fixation system developed in South Africa with the aims of reducing costs, improving ease of insertion and removal, reducing the rate of implant failure, and at the same time meeting international standards.
A University Ethics Committee approved this study of 439 patients in whom the device was used in spinal surgery between 1997 and 2002. Of these patients, 121 had follow-up radiographs taken more than one year after surgery. These radiographs were independently reviewed and form the basis of this study.
In 93.4% of patients, the fusion was radiographically solid. The state of fusion was uncertain in 4.1%, and fusion had failed in 2.5%. Screw breakage occurred in 0.3%. There were no rod breakages. In 1% of patients there was evidence of screw-bone loosening. There were no signs of screw-rod breakage or loosening.
The device produces a satisfactory rate of fusion with a very low rate of implant failure. Awarded ISO 9001:2001 certification and the CE mark, it meets international standards at considerably reduced cost.
The abstracts were edited by Prof. M.B.E. Sweet. Correspondence should be addressed to him at the Department of Orthopaedic Surgery, Medical School, University of the Witwatersrand, 7 York Road, Parktown, 2193 South Africa
