Investigation of clinical efficacy of screw fixation with cortical bone trajectory for adjacent segment disease after lumbar interbody fusion

To evaluate the clinical efficacy of screw fixation with cortical bone trajectory for adjacent segment disease after lumbar interbody fusion. A total of 14 patients with adjacent segment disease were enrolled, and a retrospective analysis was performed. All patients experienced posterior lumbar interbody fusion of the affected segments combined with internal fixation of cortical bone trajectory screw. Operation time, intraoperative blood loss, and complications were recorded. Clinical outcomes was evaluated by Visual Analogue Scale, Oswestry disability index, and Japanese Orthopaedic Association score. X-ray and computed tomography and sagittal reconstruction were used to check regularly during the follow-up. Bone graft fusion rate was evaluated by Brantigan classification. Preoperatively, Visual Analogue Scale, Oswestry Disability Index, and Japanese Orthopaedic Association scores were 7.0 ± 1.0, 72.2 ± 3.2, and 11.9 ± 1.3 points, respectively. At the 12th month after surgery, their scores were 1.9 ± 0.7, 28.6 ± 1.2, and 23.7 ± 0.9 points, respectively, which were significantly improved compared with those before surgery, and there were statistical significance in all differences (all p < 0.05). At the 12th month after surgery, X-ray and computed tomography showed there were no complications related to internal fixation, such as breakage and displacement. At the 12th month after surgery, according to the Brantigan classification, 10 patients were classified as Grade E, 3 as Grade D, and 1 as Grade C, with a fusion rate of 92.9%. At the final follow-up, clinical outcomes were assessed by the Stauffer-Coventry criteria: there were 10 patients with excellent outcomes, 1 with good outcomes, 3 with fair outcomes, and 0 with poor outcomes, with an excellent and good rate of 78.6%. The clinical outcomes of posterior lumbar interbody fusion combine with cortical bone trajectory screw for adjacent segment disease without removing the previous internal fixator were satisfactory, but further clinical researches were still required to explore its long-term outcome.