Modified Posterior Short-Segment Pedicle Screw Fixation at The Fracture Level for Treatment of Upper Lumbar Burst Fracture

Abstract

Introduction Upper lumbar burst fractures (L1or L2) are often followed by bilateral pedicle screw fixation at the level of fracture using posterior short-segment pedicle instrumentation. However, it can aggravate the trauma to the fractured vertebra. We have introduced a modified technique of posterior short-segment instrumentation for the treatment of upper lumbar burst fracture. The aim of this study was to compare the clinical and radiologic results of modified technique versus conventional technique using posterior short-segment pedicle instrumentation in the treatment of upper lumbar burst fractures. Methods The data from 64 patients with upper lumbar burst fracture who had undergone posterior short-segment instrumentation from April 2014 to November 2018 in our clinic were evaluated in the present retrospective study. All the patients were divided into 2 groups according to the surgical technique, including 27 patients (modified order of intraoperative pedicle screw placement) in modified group and 37 patients (conventional order of intraoperative pedicle screw placement) in conventional group. The clinical outcomes and radiological parameters were evaluated preoperatively, postoperatively, at 3-month follow-up and final follow-up.Results Technical success was achieved in all 64 patients. The operation time of modified group(130.4±32.4min) is significantly longer than conventional group (115.3±26.8min, p<0.05). Significant improvement in the anterior vertebral height(AVH) ratio (97.9%±6.7% in modified group, 94.1%±7.8% in conventional group, p<0.05) was found postoperatively, (100.1%±9.7% in modified group, 89.6%±6.7% in conventional group, p<0.01) at the 3-month follow-up and(98.8%±7.7% in modified group, 90.9%±7.6% in conventional group, p<0.01) at the final follow-up. And post-operative correction of AVH ratio was significantly better in modified group (45.0%) than in conventional group (38.8%, p<0.01). There was 1 case of wound infection in both groups respectively. No instrument loosening or failure, or breakage was observed during follow-up.Conclusions Modified technique and conventional technique of posterior short-segment pedicle screw fixation for upper lumbar burst fractures both provided immediate stability and reduction of post-traumatic segmental kyphosis. In addition, modified technique of posterior short-segment pedicle screw fixation seems to be a promising method for upper lumbar burst fractures because it led to better reduction of fractured vertebra than in patients who received conventional technique.