Does the length of the intermediate pedicle screw influence outcome in unstable thoracolumbar burst fractures? A prospective randomized study in India.

Abstract

Study design: A prospective randomized study.

Purpose: To investigate the impact of intermediate pedicle screw length on radiological and functional outcomes in unstable thoracolumbar burst fractures (TLF) treated with short-segment posterior fixation (SSPF).

Overview of literature: Although intermediate screws confer biomechanical advantages, there is no consensus on the ideal intermediate screw length.

Methods: Sixty-six patients with unstable TLF (Load Sharing Classification score ≥7) and normal neurology requiring SSPF were randomized into two groups. Group 1 (long intermediate screw [LIS]) underwent SSPF with a long intermediate screw (occupying >50% of the vertebral body, length ≥40 mm), while group 2 (short intermediate screw [SIS]) received a short intermediate screw (occupying <50% of the vertebral body, length ≤35 mm). Radiological parameters (restoration of anterior body height [ABH], posterior body height [PBH], ABH/PBH ratio, local kyphosis angle [LKA], and regional kyphosis angle [RKA]) and functional parameters (Visual Analog Scale score and Oswestry Disability Index) were evaluated.

Results: Demographic variables (age, sex), mode of injury, and fracture pattern were comparable between groups. The LIS group showed a significant improvement in RKA correction in the immediate postoperative period (p =0.019), but this difference was not sustained at the final follow-up (p =0.713). Other radiological and functional parameters were comparable between the two groups at the 2-year follow-up.

Conclusions: Although long intermediate pedicle screw provided better correction of regional kyphosis in the immediate postoperative period for unstable TLFs with LSC ≥7, the outcomes were comparable between both long and short intermediate pedicle screws at longterm follow-up.