Comparison of short segment posterior spinal fixation with or without index screw in thoracolumbar spinal injuries – mid-term results

Introduction: Short-segment spinal instrumentation has been advantageous in the treatment of thoracolumbar spinal fractures for better correction of kyphotic deformity. Many authors considered that together with the rods with lordotic contour, pedicle screw fixation at the fractured vertebra can cause a forward driving force to augment the reduction, and help to directly elevate the end plate to assist in the restoration of the compressed vertebral height. So it is worthwhile to study the functional and radiological outcome of short-segment fixation of thoracolumbar spine fracture with or without an index screw. Material and methods: A total of 108 patients (44 retrospective and 64 prospective) underwent posterior stabilisation with pedicle screws and rod construct under radiographic guidance. The only difference in the two groups is the insertion of an index screw in the fractured vertebra. Neurological and functional outcomes of all patients were analysed with the ASIA scale, Denis pain score and Denis work scale preoperatively, postoperatively and at 9 months. Radiographic assessment was done with a preoperative radiograph and CT scan measuring regional kyphotic angle at preoperative, postoperative and final follow-up. Results: Of the total 108 patients with dorsolumbar vertebral fracture- Group-A had 28 patients without index screws, Group-B had 80 patients with index screw in the fractured vertebra. Postoperatively, we found neurological improvement by 1 grade according to the ASIA scale but there was no significant difference between the two groups. We found no significant difference in the neurological and functional outcomes but the change in kyphotic angle between the immediate postoperative period and 9 months follow-up was significantly less in group B. Conclusion: The addition of an index screw in the thoracolumbar fractures will help in better kyphosis correction, less correction loss in kyphotic angle in the postoperative period with fewer instrument failures, without additional complications.