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

Study design: This study is a retrospective case analysis.

Objective: 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.

Summary of background data: 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.

Methods: 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.

Result: 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.

Conclusions: 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.