Delayed Occipitocervical Instability With Cranial Settling After Far-Lateral Transcondylar Surgery for Invasive Skull Base Tumor.

BACKGROUND Occipitocervical instability is a rare but potentially severe complication of a far-lateral transcondylar surgical approach to the skull base. OBJECTIVE To investigate the incidence of clinically significant occipitocervical instability after transcondylar surgery via a far-lateral approach and to determine whether the extent of occipital condyle resection relative to the hypoglossal canal was associated with the development of occipitocervical instability. METHODS A retrospective review of patients undergoing far-lateral transcondylar surgery was performed at our institution to identify patients who developed postoperative occipitocervical instability. RESULTS Of the 61 far-lateral transcondylar operations performed, the authors identified 2 cases of delayed occipitocervical instability after surgery. In each case, the patient had tumor invading into the occipital condyle and supracondylar region and a resection extending anterior to the hypoglossal canal was performed. Both patients presented with pathological fractures and a severe occipitocervical deformity. CONCLUSION Patients who have tumor involvement of the occipital condyle and supracondylar region and undergo partial unilateral condylar resection are at risk for occipitocervical instability and should be considered for occipitocervical fusion.