Application of 3D printing and intraoperative navigation in surgical treatment for atlantoaxial dislocation

Objective To evaluate the clinical feasibility and effectiveness of digital orthopedic technology (3D printing and intraoperative navigation) in the surgery of posterior atlantoaxial dislocation. Methods We reviewed the clinical data of 39 cases of atlantoaxial dislocation which had been treated from June 2009 to June 2014. Eighteen patients were treated by conventional posterior atlantoaxial reduction, atlantoaxial pedicle screw fixation, and fusion surgery (conventional group), including 11 males and 7 females, aged from 34 to 71 years (mean, 52.7±12.3 years). Twenty-one patients received posterior surgery aided by 3D printing models and real-time intraoperative navigation system (3D Group), including 12 males and 9 females, aged from 30 to 71 years (mean, 51.1±11.4 years). The feasibility and clinical efficacy of digital orthopedic technology were evaluated by comparing the 2 groups in terms of operation time, blood loss, visual analogue scale (VAS) score, cervical Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and accuracy of pedicle screwing. No significant difference was found in preoperative general data between the 2 groups (P>0.05). Results The conventional and 3D groups were followed up for respectively 43.7±5.4 months and 21.3±3.2 months. There were statistically significant differences between the 2 groups in terms of operation time (100.2±9.4 minutes versus 84.8±8.2 minutes), blood loss (94.2±9.6 mL versus 85.6±8.0 mL) and accuracy of pedicle screwing [98.6% (71/72) versus 100% (84/84)] (P 0.05). There were significant differences in VAS score, JOA score, and NDI between pre-surgery and one year post-surgery (P< 0.05) in both groups. All the patients in both groups finally obtained bony fusion, with no complications like loosening, displacement and breakage of internal fixation. Conclusions Application of digital orthopedic technology (3D printing and intraoperative navigation) in the surgical treatment of reductive atlantoaxial dislocation can increase accuracy of screwing, reduce surgical risk and improve surgical safety and outcomes. This new technology is effective, feasible and worthy of spreading. Key words: Atlas; Axis; Dislocation; Computer simulation; 3D printing; Navigation template