Use of compound 3D printing navigation template to assist pedicle or laminar screw placement in axis

English Keywords:Axis  Internal fixation  Computer-assisted design  3D printing technology

English Abstract:

  【Abstract】 Objectives: To explore the feasibility and efficacy of the compound 3D printing navigation template in assisting the axis pedicle or laminar screw placement. Methods: 32 patients, 20 males and 12 females, aging from 21 to 77, with an average age of 57.3±9.0, with posterior internal fixation from our hospital during January 2015 to May 2017 were retrospectively analyzed; all of them were followed for more than 12 months. Among them, 18 cases of pedicle or laminar screws placement were operated by using compound 3D printing navigation template which was designed according to preoperative simulated nailing(observation group). 14 cases of pedicle screw placement were operated by free hand(control group). The blooding and nailing duration were recorded; the accuracy of screw placement was evaluated by Kawaguchi criteria; the deviation of nailing point and nailing direction between simulated screw and postoperative screw were calculated; all above parameters were statistically analyzed. Results: All patients underwent surgeries without serious complications such as nerve or blood vessel injury. A total of 36 screws were placed in the experimental group, including 22 pedicle screws and 14 laminar screws, nailing duration was 31.5±6.5min, blood loss was 45.0±19.2ml, according to Kawaguchi criteria, 32 screws were in grade 0, 4 screws in grade Ⅰ and 0 screw in grade Ⅱ, and nailing accuracy was 100%. A total of 28 screws were placed in the control group. Nailing duration was 57.6±6.9min, blood loss was 228.5±57.9ml, according to Kawaguchi criteria, 18 screws were in grade 0, 6 screws in grade Ⅰ and 4 screw in grade Ⅱ, nailing accuracy was 85.7%. There were no significant differences between the two groups in the nailing duration, blood loss and nailing accuracy(P<0.05). Angle deviation between postoperative nailing and simulated nailing was 0.69°±1.34°; the deviation between the postoperative nailing point and the simulated nailing point on the X, Y and Z axes was 0.50±2.13mm, 0.75±2.18mm, 0.43±2.39mm, respectively. There was no significant difference of above deviations between postoperative and preoperative design(P＞0.05). Conclusions: Use of compound 3D printing navigation template in assisting in the placement of pedicle screws or laminar screws can reduce nailing duration and blood loss and improve nailing accuracy. It is an alternative measure for arthroscopic pedicle screw placement failure.