STUDY DESIGN: Retrospective review.

OBJECTIVES: To determine whether radiographic measurements derived from standard computed tomography (CT) evaluation can be used to predict failure of nonoperative treatment in patients with unilateral facet fractures.

SUMMARY OF BACKGROUND DATA: There is no consensus regarding treatment of unilateral cervical spine facet fractures. Management of this injury is based primarily on the presence of neurologic deficits and the degree of perceived spinal instability. CT-based criteria for predicting failure of nonoperative treatment in this patient population have not been examined.

METHODS: Initial CT scans of all patients with unilateral cervical facet fractures were reviewed. Direct measurements included height and width of the facet fracture fragment, fracture displacement, and angulation. Calculated data included percent height and width of the fracture fragment based on the height and width of the contralateral intact facet.

RESULTS: A total of 24 patients with 26 unilateral facet fractures were identified. Five patients with 5 facet fractures failed nonoperative management and required delayed surgical stabilization. Comparing patients successfully treated nonoperatively to those failing nonoperative management, a significant difference was found in absolute height of the fracture fragment (P = 0.0002), articular fracture height (P = 0.008), and height of the fracture fragment expressed as a percentage of the contralateral intact lateral mass (P = 0.026).

CONCLUSION: The only significant risk factors identified for failure of nonoperative treatment were craniocaudal height of the fracture fragment and relative height of the fracture fragment expressed as a percentage of the intact lateral mass. This study suggests that patients with unilateral cervical facet fractures involving >40% of the absolute height of the intact lateral mass or an absolute height >1 cm are at increased risk for failure of nonoperative treatment. Failure of nonoperative treatment was not observed in any patient with a fracture involving less than 40% of the height of the lateral mass or an absolute height <1>cm.