A comparative research on the accuracy of pedicle screw implantation in corrective surgery for scoliosis patient with freehand, drill guide template and three-dimensional image navigation

English Keywords:Scoliosis  Pedicle screws  Freehand  Guide template  Computer navigation

English Abstract:

  【Abstract】 Objectives: To compare the accuracy of free-hand implantation, drill guide template and 3D image navigation implantation for pedicle screw in corrective surgery for scoliosis. Methods: This study included 32 patients(mean age 32.8±21.0 years) with scoliosis who underwent corrective surgery in Peking University Third Hospital from February 2014 to December 2019. The patients were divided into three groups according to the pedicle screw implantation technique: group A using free-hand(10 patients with 163 pedicle screws), group B using drill guide template(11 patients with 176 pedicle screws), and group C using three-dimensional image navigation(11 patients with 191 pedicle screws). Total spine X-ray and CT were routinely performed before and after surgery, and the drill guide template was built according to thin-slice CT in group B. In group C, the real time 3D image navigation was applied in assistant to pedicle screw implantation. The Cobb angle before and after surgery, apex rotation and transverse diameter of pedicle before surgery were measured. The accuracy rate of screws were measured by Gertzbein′s method and satisfactory rate was calculated. Results: The Cobb angle of 32 patients was 69.4°±21.3°(35.0°-115.0°) before surgery, 23.0°±12.9°(2.4°-47.5°) after surgery, and the correction rate was (68.8±12.0)%(46.2％-95.0％). The rotation angle of the apex vertebral was 25.5°±8.9°(9.5°-39.0°) in group A, 31.3°±11.6°(9.9°-50.0°) in group B, and 30.7°±17.0°(11.2°-60.0°) in group C(P=0.556). The proportion of abnormal pedicle was 31.9% in group A, 33.0% in group B and 39.3% in group C(P=0.281). According to the postoperative CT evaluation of the accuracy of pedicle screw placement, the satisfaction rate of pedicle screw placement was 92.8% in group A, 89.4% in group B and 92.6% in group C(P=0.629), and there was no significant difference between the satisfaction rates of screw placement(P>0.05). The satisfaction rate in thoracic spine in group B was lower than that in groups A and C(P=0.042). There was a positive correlation between segment of spine and satisfaction rate(P=0.029, OR=1.086, 95%CI: 1.008-1.169), but a negative correlation between the Cobb angle before surgery and satisfaction rate(P=0.005, OR=0.964, 95%CI: 0.939-0.989). The operative time of group A, B, C was 350±114min， 447±133min， 414±128min, respectively, with no significance among three groups(P=0.219). In group A, a patient suffered from wound hematoma. In group B, a patient had neurological deterioration due to the screw misplacement and a patient suffered from cerebrospinal fluid leakage, and one patient suffered from non-screw-related neurological deterioration. One patient suffered from deep venous thrombosis with pulmonary infection, and intercostal neuralgia. In group C, a patient suffered from delayed intrapleural hemorrhage, and another patient suffered from surgical site infection. Conclusions: Free-hand technique, drill guide template and intraoperative navigation have similar accuracy in pedical screw implantation in scoliosis surgery. Intraoperative navigation may have advantages in abnormal thoracic pedicle screws.