Clinical Application Of 3d Printing In Pedicle Screw Fixation And Fusion For The Treatment Of Old Type Ii Odontoid Fractures With Posterior Atlantoaxial Dislocation

Objective: To evaluate the clinical value of 3D printing in old type II odontoid fracture with posterior pedicle screw fixation and fusion of posterior atlantoaxial dislocation. Methods: From September 2014 to February 2016, a total of 19 patients with old type II odontoid fracture and with atlantoaxial dislocation were enrolled in the department of Spine Surgery, Affiliated Chenggong Hospital of Xiamen University. The patients included 10 males and 9 females, with ages ranging from 27 to 68 years old and an average of 46.9 years old. The patients were divided into two groups (experimental group of 13 cases, the control group of 6 cases) according to whether they were given 3D printing assisted surgery. The posterior pedicle screw implantation with 3D printing navigation template was performed in the experiment group and traditional X-ray-assisted posterior atlantoaxial pedicle screw fixation was carried out in the control group. The cervical spine was scanned by computed tomography (CT) after operation to evaluate the accuracy of the surgery in the two groups. The bleeding volume, wound drainage volume and operation time were also compared between the two groups. Results: 38 screws were inserted into the atlas and another 38 screws were placed in the axial of the 19 patients. According to Richter et al.'s criteria, the accuracy rate of 52 screws in the experiment group was 100%, with 51 screws (98.1%) in Grade 1 and 1 screw (1.9%) in Grade 2. The accuracy rate of 24 screws in the control group was 95.8%, with 21 screws (87.5%) in Grade 1, 2 screws (8.3%) in Grade 2 and 1 (4.2%) in Grade 3. The accuracy rate of the screws was significantly different (P<0.05) between the two groups. The bleeding volume in the experiment group (116 +/- 37 ml) was significantly lower than that in the control group (192 +/- 69 ml, P<0.05). The wound drainage volume in the experiment group (79 +/- 32 ml) was also markedly less than that in the control group (116 +/- 35 ml, P<0.05). The operation time in the experiment group (83 +/- 20 min) was significantly shorter than that in the control group (116 +/- 26 min, P<0.05). Conclusion: This study clearly demonstrated that 3D printing navigation template technique is an accurate, safe and rapid method with promising potential in the clinical treatment of old type II odontoid fracture with atlantoaxial dislocation.