Sagittal Angle of Pedicle Screws as a Influencing Factor for Postoperative Collapse of Thoracolumbar Fractures: A Case-control Study.

Abstract

This study is a retrospective case analysis. This study evaluates the impact of varying pedicle screw angles on postoperative vertebral body collapse in patients with single-segment thoracolumbar fractures managed with short-segment pedicle screw fixation. Thoracolumbar fractures are prevalent in spinal trauma. Posterior pedicle screw fixation treat for single-segment fractures often encounters the challenge of postoperative vertebral collapse. While the causes are multifactorial, the impact of the pedicle screw's sagittal angle on collapse remains understudied. We retrospectively analyzed 38 patients, grouped by pedicle screw angle in the sagittal plane, comparing postoperative and final follow-up height of the injured vertebrae. Analysis of the injured vertebrae height postoperatively and at final follow-up revealed the following: (1) with PTH in the upper vertebral body, vertebra height decreased. PTT reduced anterior edge height (P<0.05), with no effect on the middle or rear edges height. (2) No height changes occurred with PTH in the lower vertebral body. Instead, PTT reduced anterior edge height (P<0.05), with stable middle and rear edge heights. (3) No height changes with dorsal opening angles between upper and lower pedicle screws. Instead, ventral opening reduced anterior edge height (P<0.05), with stable middle and rear edge height. To preserve postoperative vertebral height in single-segment thoracolumbar fractures, optimal pedicle screw placement involves directing the upper screw tip towards the tail (PTT) and the lower towards the head (PTH). Form a dorsal opening angle between the upper and lower screws after rod connection.