The Posterior Fixation of Thoracolumbar Burst Fracture using Pedicle Screws and Caudal Offset Sublaminar Hooks

Abstract

Study Design: A retrospective study O b j e c t i v e s: We analyzed the clinical results of thoracolumbar burst fractures, managed by posterior fixation of 2 segments above and 1 segment below, using an offset sublaminar hook. Summary of Literature Review: Mono-segment fixation above and below the injured vertebra, using posterior pedicle screw fixation, has the benefit of saving the uninjured mobile lumbar segment in thoracolumbar junction burst fracture patients. However, in a severely comminuted vertebral body, mono-segment fixation may not prevent loss of correction and metal failure. Options for such cases are additional anterior column support or long segment fixation, including 2 segments above and 1 below the injured vertebra. Instead of fixing 2 segments below the fracture level, fixation of one segment below, using the offset sublaminar hook, can save the uninjured segment, especially in the upper lumbar segment, with greater fixation strength than mono-segmental screws only. Material and Method: The study included eleven patients with a thoracolumbar junction burst fracture, which underwent posterior fixation using pedicle screws in 2 segments above and 1 segment below, aided by an offset sublaminar hook. The mean follow-up period was 30.7 months (range, 24 to 58 months). Radiographs taken at follow-up were evaluated for implant loosening, correction loss, change in pedicle screw angle, and loss of vertebral height, adjacent segment instability and junctional degenerative change. The clinical results were collected in out-patient department. Results: No implant loosening was noted. No case showed adjacent instability, acceleration of junctional degenerative change at the lower end of lumbar segment or hook dislodgement. Also, there were no junctional area related symptoms. Conclusion: For posterior surgery of thoracolumbar burst fractures, this construct, fixing 2 segments above and 1 segment below injured vertebra, aided by an offset sublaminar hook, was satisfactory in maintaining fracture reduction, and showed no instability or acceleration of degeneration on adjacent segnents.