Aortic abutment after direct vertebral rotation: plowing of pedicle screws

Abstract

Study design: Retrospective case series.

Objective: To report the occurrence of pedicle screw plow after individual-level direct vertebral rotation (DVR) that resulted in critical screw proximity to the aorta, from three institutions over a four-year period (2004-2008).

Summary of background data: Thoracic pedicle screws are generally accepted as safe implants that possess sufficient strength to correct the coronal, sagittal, and now transverse plane deformities associated with scoliosis. Structural failure of the bone resulting in translation of the screw in the transverse plane, defined as plow, can occur with individual-level DVR.

Methods: We performed a retrospective review of all pediatric patients who underwent posterior spinal fusion with pedicle screws for neuromuscular and idiopathic scoliosis and underwent postoperative computed tomographic scan. We identified all patients who required a secondary procedure for implant removal because of malposition of the screw.

Results: Six patients with lateral screw direction after a DVR maneuver required screw removal because of proximity to the aorta. All patients had intraoperative confirmation of adequate screw placement before introducing the rod and performing derotation. CONCLUSIONS.: The biologic limitations of vertebrae are approached as we strive to achieve further correction of the spine. Surgeons' experience and methods to assess proper screw placement may give a false sense of adequate final implant position after DVR. Vigilance to ensure proper pedicle screw position can avoid potential iatrogenic catastrophes.