Bilateral Medial Medullary Syndrome Following Anterior Odontoid Screw Fixation for a Type II Fracture: A Case Report.

INTRODUCTION

Medial medullary syndrome is an uncommon brainstem stroke, and bilateral involvement is rarer still. It has not, to our knowledge, been described as a complication of anterior screw fixation for a type II odontoid fracture.

CASE REPORT: A 28-year-old man sustained a posteriorly displaced type II odontoid fracture with an associated C2 spinous process fracture in a road traffic accident. He was neurologically intact at admission. Surgery was briefly postponed after a transient episode of anisocoria during induction that resolved without deficit and with a normal computed tomography (CT) angiogram. Halo-ring traction was applied preoperatively for 3 days to achieve gradual fracture reduction, and anterior fixation with two cannulated lag screws was performed uneventfully. Weaning from ventilation was prolonged and complicated; cerebral CT was unremarkable, but magnetic resonance imaging (MRI) showed acute bilateral medial medullary ischemia. He developed a bilateral incomplete tetraparesis, predominantly left-sided, with pyramidal signs and a right hypoglossal palsy (American Spinal Injury Association [ASIA] C)]. Tracheostomy, gastrostomy feeding, anticoagulation, antiplatelet therapy, and early rehabilitation were instituted. Severe atherosclerosis of the bilateral vertebral and basilar arteries, in a patient with hypertension, dyslipidemia, and long-standing smoking, was the only etiological factor identified. At 6-month follow-up, he had improved to ASIA D and was ambulating short distances with a cane.

CONCLUSION

Postoperative brainstem ischemia should be suspected whenever weaning fails or new deficits appear after upper cervical spine surgery, even with a normal CT; MRI with diffusion-weighted sequences is required to confirm the diagnosis. Perioperative manipulation of the cervical spine in a patient with underlying atherosclerosis may be an under-recognized mechanism for this rare complication.