An Unusual Cause of Buttock Pain after Posterior Thoracolumbar Fixation: Rod Migration into the Pelvis

INTRODUCTION: Posterior surgical stabilization is commonly indicated for unstable thoracolumbar fractures. Short segment stabilization has the advantage of preserving mobile segments and reducing excessive loads on the adjacent discs but is not without complications. Rod migration is an extremely rare complication after thoracolumbar fracture fixation and can lead to catastrophic visceral and vascular injuries. To the best of our knowledge, this is the first case report of a surgically managed distant rod migration into the posterior sacrum and pelvis after a posterior thoracolumbar trauma fixation. CASE REPORT: A 25-year-old male patient presented to our center with complaints of the right buttock and groin pain for 8weeks. He had a history of an unstable thoracolumbar fracture treated by a short segment posterior stabilization 5years back. On examination and investigations, we found that the right-sided rod migrated into the posterior sacrum and partly into the pelvis. The fracture had united well in kyphosis. Anticipating complications, the rod was removed through an incision over buttock. The other implants were also removed. The patient was asymptomatic at 2-year follow-up. CONCLUSION: One should keep in mind the rare possibility of rod migration during follow-up of thoracolumbar trauma fixation. A proper history and clinical examination may guide the surgeon into such a rare possibility. Radiological investigations should be performed if there is suspicion and surgery may be advised when complications are anticipated depending on the location of the rod.