Posterior revision surgery using an intraarticular distraction technique with cage grafting to treat atlantoaxial dislocation associated with basilar invagination

OBJECTIVE The treatment of atlantoaxial dislocation (AAD) and basilar invagination (BI) is challenging, especially in symptomatic patients with a history of previous surgery. Although seldom reported, posterior revision surgery to revise prior constructs can be advantageous over an anterior or combined approach. The authors describe their experience in performing posterior revision surgery using Goel’s technique. METHODS The authors reviewed patients with AAD and BI who had undergone previous posterior surgery at the cranio-cervical junction between January 2016 and September 2017. All of these patients underwent revision surgery from a posterior approach. The Japanese Orthopaedic Association (JOA) score was used to assess clinical symptoms before and after surgery. The distance from the tip of the odontoid to Chamberlain’s line, atlantodental interval (ADI), and clivus-canal angle (CCA) were used for radiographic assessment before and after surgery. RESULTS Twelve consecutive patients were reviewed. Prior surgeries were as follows: 4 patients (4/12) with posterior osseous decompression without fusion, 7 (7/12) with reduction and fusion without decompression, and 1 (1/12) with posterior osseous decompression and reduction and fusion. With the use of Goel’s technique for revision in these cases, distraction using facet spacers afforded release of the anterior soft tissue from a posterior approach. The occiput was fixated to C2 using a cantilever technique, and autologous cancellous bone was grafted into the intraarticular joints. In all 12 patients, complete reduction of BI and AAD were achieved without injury to nerves or vessels. All patients had evidence of bony fusion on CT scans within 18 months of follow-up. CONCLUSIONS Posterior revision surgery using Goel’s technique is an effective and safe revision salvage surgery for symptomatic patients with AAD and BI.