Clinical characteristics of postoperative anterior arch fracture of the atlas following C1 laminectomy: 14-year experience of a single neurosurgical center.

Objective: Postoperative anterior arch fracture of the atlas (PAFA) is a rare but increasingly recognized complication of C1 laminectomy. However, the pathophysiology remains poorly understood. We retrospectively investigated the incidence of PAFA and associated risk factors. Methods: We retrospectively reviewed the records of patients who underwent C1 laminectomy at our institution between January 2010 and December 2023. The clinical records and radiological findings were analyzed. Atlantodental interval (ADI) and retro-odontoid distance (ROD) were measured using preoperative sagittal reconstructed computed tomography or T1-weighted magnetic resonance imaging. Results: In total, 51 patients were included in this study. The indications for surgery included posterior fossa lesions, Chiari malformation type I, cervical canal stenosis at C1, and spinal tumors. During follow-up (mean, 69 ± 34 months), PAFA developed in three (5.9%) patients. All patients underwent decompression surgery for cervical canal stenosis at C1. The mean interval between surgery and fracture detection was 11 ± 5 months. Two patients presented with neck pain, which improved with conservative treatment. One patient developed a vertebral artery occlusion and cerebral infarction associated with lateral mass displacement. Patients with PAFA were significantly older ( Conclusions: PAFA is an uncommon but important complication of C1 laminectomy, particularly in elderly patients with cervical canal stenosis at the craniocervical junction. An increased ROD may radiologically predict fracture risk. PAFA can occasionally lead to serious vascular complications; thus, careful postoperative surveillance is recommended, particularly during the first postoperative year.