Clinical Analysis of Radiologic Measurements in Patients with Basilar Invagination

Abstract Objective To investigate correlations between radiologic measurements and clinical outcomes in patients with basilar invagination (BI). Methods The medical records and radiologic data of 46 patients (27 women) that had undergone posterior atlantoaxial fusion or occipitocervical fusion for BI from January 2010 to June 2018 were retrospectively analyzed. Patients under 15 years old or with a polytraumatic, tumorous, or infectious pathology were excluded. The modified Ranawat method (MRM) and the Redlund-Johnell method (RJM) were used to obtain radiographic measurements of basilar invagination preoperatively, subacute postoperatively, and at 3-month and last follow-up. Visual Analogue Scale (VAS), Neck Disability Index (NDI) and Japanese Orthopedic Association (JOA) scores were also assessed. Correlations between MRM and RJM measurements and clinical outcomes were evaluated. Results Mean age of patients was 59.9±16.5 years, mean body mass index was 23.5±4.6 kg/m 2 , and Mean follow-up was 37.9±23.8 months. Postoperative radiologic measurements increased about 36% of preoperative radiologic measurements. Subsidence at the C1-2 joint occurred in most patients at 3 months postoperatively, but clinical outcomes did not deteriorate. JOA scores were linearly correlated with percentage increases in both radiologic measurements subacute postoperatively ( p Conclusion The subacute postoperative neurological outcomes of BI patients are significantly related with the amount of vertical reduction.