Clinical observation of 3D printed external guide plate assisted percutaneous pedicle screw fixation in the treatment of thoracolumbar fractures

English Keywords:Thoracolumbar fracture  3D printed external guide plate  Pedicle screw  Minimally invasive

English Abstract:

  【Abstract】 Objectives: To observe the clinical effect of 3D printed external guide plate assisted percutaneous pedicle screw fixation in the treatment of thoracolumbar fractures. Methods: A retrospective analysis was performed on 47 patients with thoracolumbar fractures who underwent percutaneous pedicle screw fixation from August 2017 to August 2020, including 13 males and 34 females, aged 21-69 years. The patients were all single-segment fractures, involving T12 in 11 cases, L1 in 26 cases, L2 in 7 cases, L3 in 2 cases, and L4 in 1 case. 22 cases were treated with 3D printed customized in vitro guide plates made before surgery in simulating screw placement and assisting placement during operation(guide plate group), and the other 25 cases were treated with freehand screw placement under X-ray fluoroscopy(freehand group). The operative time, screw placement time, intraoperative X-ray fluoroscopy times, intraoperative blood loss, and postoperative complications were compared between the two groups. The Neo classification was used to evaluate the grades of screw placement in the two groups, and the accuracy of screw placement was calculated. The anterior height of the fractured vertebral body and the Cobb angle were measured on the preoperative and postoperative X-ray images, and the sagittal plane index of the vertebral body was calculated to evaluate the reduction and correction of the fracture. The visual analogue scale(VAS) score, Japanese Orthopedics Association(JOA) score and Oswestry disability index(ODI) were recorded before operation and at 1 day, 7 days and 1 year after operation. Results: The operative time, screw placement time, intraoperative X-ray fluoroscopy times, and intraoperative blood loss of the guide plate group were all less than those of the freehand group, which were 63.57±12.18min vs 85.56±16.27min, 23.69±3.63min vs 41.36±8.12min, 15.26±4.15 vs 26.93±6.93, and 48.82±13.72ml vs 74.35±18.64ml, respectively, and the differences were with statistical significance(P<0.05). The accuracy of screw placement was 97.54% of the guide plate group with 119 screws of grade 0 and 3 screws of grade 1, which was higher than that of the freehand group of 92.09% with 128 screws of grade 0, 10 screws of grade 1, and 1 screw of grade 2, and the difference was statistically significant(P<0.05). The anterior height of the vertebral body, sagittal index of the vertebral body, and Cobb angle of the two groups after operation were improved significantly compared with those before operation(P<0.05), and no significant difference was found between the two groups at the same time points(P>0.05). The VAS score, JOA score and ODI of the two groups after operation were significantly improved compared with those before operation(P<0.05), and there was no statistical difference between the two groups at the same time points(P>0.05). The injured vertebrae in patients of both groups achieved bone healing after operation, and no postoperative complications occurred. Conclusions: 3D printed external guide plate assisted percutaneous pedicle screw fixation can achieve good results in the treatment of single-segment thoracolumbar fractures, which can improves the screw placement accuracy significantly, shortens the operative time, and reduces the intraoperative radiation exposures comparing with freehand percutaneous pedicle screw fixation.