Thoracolumbar injuries : short segment posterior instrumentation as standalone treatment - thoracolumbar fractures
Thesis (MMed (Surgical Sciences. Orthopaedic Surgery))--University of Stellenbosch, 2010.
Objective: This research paper reports on the radiographic outcome of unstable thoracolumbar injuries with short segment posterior instrumentation as standalone treatment; in order to review rate of instrumentation failure and identify possible contributing factors. Background: Short segment posterior instrumentation is the treatment method of choice for unstable thoracolumbar injuries in the Acute Spinal Cord Injury Unit (Groote Schuur Hospital). It is considered adequate treatment in fracture cases with an intact posterior longitudinal ligament, and Gaines score below 7 (Parker JW 2000); as well as fracture dislocations, and seatbelt-type injuries (without loss of bone column - bearing integrity). The available body of literature often states instrumentation failure rates of up to 50% (Alanay A 2001, Tezeren G 2005). The same high level of catastrophic hardware failure is not evident in the unit researched. Methods: Sixty-five consecutive patients undergoing the aforementioned surgery were studied. Patients were divided into two main cohorts, namely the “Fracture group” (n=40) consisting of unstable burst fractures and unstable compression fractures; and the “Dislocation group” (n=25) consisting of fracture dislocations and seatbelt-type injuries. The groups reflect similar goals in surgical treatment for the grouped injuries, with reduction in loss of sagittal profile and maintenance thereof being the main aim in the fracture group, appropriately treated with Schantz pin constructs; and maintenance in position only, the goal in the dislocation group, managed with pedicle screw constructs. Data was reviewed in terms of complications, correction of deformity, and subsequent loss of correction with associated instrumentation failure. Secondly, factors influencing the aforementioned were sought, and stratified in terms of relevance. Results: Average follow up was 278 days for the fracture group and 177 days for the dislocation group (all patients included were deemed to have achieved radiological fusion – if fusion technique was employed). There was an average correction in kyphotic deformity of 10.25 degrees. Subsequent loss in sagittal profile averaged 2 degrees (injured level) and 5 degrees (thoracolumbar region) in the combined fracture and dislocation group. The only factor showing a superior trend in loss of reduction achieved was the absence of bone graft (when non-fusion technique was employed). Instrumentation complications occurred in two cases (bent connection rods in a Schantz pin construct with exaggerated loss in regional sagittal profile, and bent Schantz pins). These complications represent a 3.07% hardware failure in total. None of the failures were considered catastrophic. Conclusion: Short segment posterior instrumentation is a safe and effective option in the treatment of unstable thoracolumbar fractures as a standalone measure.