Causes and therapeutic strategies for atlantoaxial dislocation revision surgery

English Keywords:Atlantoaxial dislocation  Revision surgery  Cause analysis  Therapeutic strategies

English Abstract:

  【Abstract】 Objectives: To analyze the causes of postoperative revision surgery of atlantoaxial dislocation, and to discuss the therapeutic strategies. Methods: 15 patients with atlantoaxial dislocation revision surgeries(11 male, 4 female; 15-68 years, mean 46.60±14.95 years) were analyzed in this retrospective study. The intervals of two operations ranged from 2 to 120 months(28.73±38.59 months). The reasons were analyzed for revision surgery according to the image data and intraoperative findings. All patients received 8-10kg high dose skull traction and posterior release during revision surgery. For patients with integral posterior structure, the option of anterior release depended on the degree of reduction. After decompression and reduction, all patients received posterior internal fixation. One patient who received posterior decompression in the primary operation was performed with anterior decompression and fixation. Assisted atlantoaxial screw placement under 3D navigation template was performed; autogenous iliac cancellous bone was placed. The atlantoaxial reduction, screw position, bone graft fusion and surgical efficacy were evaluated at follow-up. Results: Reasons for revision were as following: 10 cases of insufficient decompression/reduction, 3 cases of failed internal fixation, 3 cases of unfused bone graft(including 1 case of internal fixation failure caused by unfused bone graft ). Among all the 15 revision surgeries, 14 cases received posterior fixation surgery, 1 case received anterior fixation surgery. By intraoperative skull traction and full release, 13 cases achieved anatomical reduction, the other 2 cases did not reach anatomical reduction due to extensive bony fusion and were fully decompressed after odontoidectomy. 42 atlantoaxial screws were implanted with 3D template-assisted navigation, the accuracy of screw implantation was 97.6%. The follow-up time ranged from 3 to 36 months(16.0±4.2 months). All patients got bone fusion, the fusion time ranged from 3-6 months(3.7±0.5 months). The final JOA score ranged from 11 to 16( mean, 13.8±3.1), which improved compared with the preoperative(range form 6 to 11, mean 8.1±2.3), the improvement rate was (64.0±21.2)%(45.4%-88.8%). Conclusions: Inadequate decompression/reduction, failed internal fixation, and unfused bone graft are the common reasons of C1-2 dislocation needing revision surgery. Intraoperative full release, 8-10kg skull traction, and proper bony structure resection are leading to the reduction of atlantoaxial dislocation, 3D navigation template is beneficial to the accuracy of screw placement.