Intrathecal Migration of a Broken Posterior Spinal Rod: A Case Report

Abstract

An unusual complication of intrathecal broken rod migration into the dural sac following spinal instrumentation is reported. The clinical and radiographic records were retrospectively evaluated for a 49-year-old, morbidly obese woman who presented with walking difficulty and pitching forward posture 11 years after posterior spinal fusion. The radiographs demonstrated a foreign body consistent with a broken spinal rod that had migrated to the midline behind the L6-S1 disc. Because of the persistent symptoms and suspected implant failure, the patient was taken to the operating room for exploration and posterior spinal instrumentation from L1-S1. A round hole in the thecal sac measuring 6 mm in diameter was identified medial and proximal to the L6 pedicle screw. The mobile, broken rod measuring 23 x 5.5 mm inside the thecal sac was removed after durotomy following localization by C-arm fluoroscopy. After removal of the rod and re-instrumentation, the patient's neurologic symptoms resolved and her back pain was resolved.