THE BWM SPINAL FIXATOR SYSTEM - A PRELIMINARY-REPORT OF A 2-YEAR PROSPECTIVE, INTERNATIONAL MULTICENTER STUDY IN A RANGE OF INDICATIONS REQUIRING SURGICAL INTERVENTION FOR BONE-GRAFTING AND PEDICLE SCREW FIXATION

Study Design. A prospective, international, multi-center study of 400 patients who received the BWM fixator system. Objectives. To assess th e effectiveness and safety of the system in the management of various conditions requiring spinal fixation and bone grafting. Summary of Bac kground Data. The BWM system was developed for the management of spina l instability of all etiologies occurring in the thoracic, thoracolumb ar, and lumbosacral spine. Methods. Patients with fracture, tumor, spo ndylolisthesis, spondylitis, failed back, or other degenerative condit ions of the spine received the BWM instrumentation as described in the study literature and were regularly reviewed for 2 years. Results. Th e results from the first 200 patients to complete the study showed an overall graft fusion rate of 94% (95% confidence interval: 91.3%-97.6% ). There were marked improvements in measures of functional ability (P < 0.001, Wilcoxon test). Before surgery, less than half the patients were capable of outdoor activity. At 2 years, 80% were able to underta ke outdoor activity. There were few perioperative difficulties reporte d. Postoperative complications associated with major surgery were seen in 18% patients. There were 23 (2.6%) pedicle screw failures, includi ng two loosenings, and 13 (2.5%) spacer element failures, including th ree loosenings. Conclusions. Clinical failure was not necessarily a co nsequence of component failure. The BWM fixator provided excellent sta bilization during the process of bone graft consolidation. The risks o f complication or component failure were no higher than those associat ed with similar devices.