ANTERIOR INSTRUMENTATION OF THE SPINE IN THORACIC AND THORACOLUMBAR FRACTURES - THE SINGLE ROD VERSUS THE DOUBLE ROD SLOT-ZIELKE DEVICE

Study Design. This retrospective study analyzed the clinical and radio logic results of two groups of patients with unstable burst fractures of the thoracolumbar spine treated with anterior decompression, reduct ion of the kyphotic deformity, and stabilization by grafting and instr umentation. Objective, To compare the results regarding loss of correc tion of two groups of patients treated with two different configuratio ns of the same instrumentation, the so-called ''Slot-Zielke'' device. Summary of Background Data. Decompression of burst fractures and reduc tion of kyphotic deformity are facilitated by the anterior approach to the spine. The maintenance of reduction depends on the strength of th e grafting material and on the rigidity of the internal fixation. Meth od. Forty consecutive patients with spine fractures underwent surgery for anterior decompression, reduction of kyphotic deformity, and stabi lization by grafting and instrumentation. The first group of 25 patien ts (Group A) received a single rod ''Slot-Zielke'' device as an implan t. The second group of 15 patients (Group B) received a double rod ''S lot-Zielke'' device. Before and at least 2 years after surgery, the ky photic angle between the vertebrae above and below the fracture was me asured. Results. The clinical results at follow-up evaluation were sim ilar between the groups. In Group A, 60% of the cases had a loss of co rrection of 5 degrees or more (least square mean, 5.64 degrees; range, 0-23 degrees). In Group B, the loss of correction in all cases was le ss than 5 degrees (least square mean, 1.60 degrees; range, 0-4 degrees ). The difference between the average of both groups was highly signif icant (P = 0.014). Conclusion, The double rod instrumentation performs significantly better regarding loss of correction compared with the s ingle rod instrumentation.