Vertebral artery injury in C-1 lateral mass screw fixation

Abstract

Atlantal lateral mass screw fixation is an increasingly popular procedure that is viewed as less demanding—and with lower risk of vertebral artery (VA) injury—than atlantoaxial transarticular fixation.2,3,5 We report a case in which the VA was injured during an atlantal lateral mass screw fixation procedure, however, to draw attention to this unusual complication. Of 10 patients in whom this technique was used between 2003 and 2004, we documented one VA injury in a 76-year-old woman who suffered from depression. She sustained a Levine‐Edwards 4 Type II traumatic C-2 spondylolisthesis injury involving a C-3 compression fracture. Initial halo fixation was abandoned because of her mental state. Posterior C1‐3 fusion was planned in light of the patient’s history of pharyngeal cancer and bronchiectasis. Preoperative computed tomography (CT) scanning at C-1 revealed no abnormality (Fig. 1). During surgery, C-1 screw entry points were drilled at the intersection of the inferior border of the posterior arch and the midpoint of the lateral mass 3 without sacrificing the greater occipital nerve. Using lateral fluoroscopy, trajectories were drilled with a 2-mm bit. Unfortunately, when the left screw hole was tapped, the 4-mm tap traversed the superior wall of the posterior arch, damaging the VA (Fig. 2). Although bleeding was stopped by compression, the preoperative plan was abandoned in favor of occipitocervical fixation. The total estimated blood loss was 750 ml. A pseudoaneurysm detected immediately after surgery was evaluated every 4 months and gradually decreased in size (Fig. 3). The postsurgical course has been uneventful, requiring no further treatment, during a 30-month period of observation.