Cervicomedullary angle as an independent radiological predictor of postoperative neurological outcome in type A basilar invagination

Abstract

To propose an independent radiological index to evaluate surgical outcomes of A type basilar invagination, a retrospective study was conducted to compare the clinical outcome between procedures 1 and 2 by applying intraoperative consistent traction and manual reduction. Moreover, the atlantodental interval (ADI), cervicomedullary angle (CMA), bilateral sagittal inclination of atlantoaxial joint (SIAA) were measured and compared to pre-operation. Postoperatively, only these patients undergoing procedure 2 achieved significant neurological improvement. The ADIs and the SIAAs decreased in both groups, these differences are statistically significant between pre- and post- operation. For postoperative CMAs, only these patients undergoing modified surgery gained significant improvement of angle with mean 141°. We concluded that the CMA or SIAA could be a radiological predictor to evaluate surgical outcome in BI, among which the CMA is a more independent and easily measurable predictor that is closely correlated with satisfactory neurological improvements. Moreover, procedure 2 with intraoperative resistant cranial traction and manual reduction can help us achieve a good CMA.

Radiological assessment and surgical management of cervical spine involvement in patients with rheumatoid arthritis

“…The normal angle is 135°–175°. Patients with a cervical–medullary angle < 135° may suffer from cranial settling and clinical signs of C2 root pain [ 34 ]. Plain radiographs have not been found to be a reliable diagnostic imaging modality for the detection of BI.…”