Early experience using 3-D printed locking drill guides for transpedicular screw fixation in scoliosis

Introduction

 The preparation of the pedicle and the insertion of a transpedicular screw is a high-risk procedure during spine surgeries. To avoid pedicle screw misplacement in posterior spinal deformity surgery, patient specific 3D‐printed guides can be used but technical issues reported in 17% of screw fixations. To address this concern, our team has developed single-level guide templates and a locking screw mechanism. We share our experience using a surgical planning and support system with 3D printed patient-specific guides that utilize a locking screw, highlighting the advantages of incorporating it into complex spine surgeries.

Materials and Methods

The surgical planning and support system is composed of six phases: (1) spine digitization, (2) segmental analysis and vertebral characterization, (3) planning of angulation, depth, and diameter of transpedicular screws, (4) 3D printing of the spine model, and the locking single level drill guides, (5) selection of surgical instruments, and (6) surgery.

Illustrative cases

High resolution tomographic images of two 15-year-old females and one 16-year-old male were processed through software analysis for segmental analysis and vertebral characterization. This process aimed to propose the most suitable plan in a multidisciplinary meeting. Sterilized 3D-printed patient-specific locking spine drill guide models were utilized for the spinal instrumentation.

Conclusions

 Multiple countries are now developing 3D printed drill guides for screw fixation in severe scoliosis. Our guide represents the first one using a transitory locking mechanism to improve accuracy of fixation. The 3D printed locking drill guides enabled accurate insertion and direction of the transpedicular screw, resulting in improvements in sagittal and coronal balance, and all screws classified as accurately placed and with minimal difference with the planned trajectory. Additional outcomes such as surgical time, intraoperative bleeding, radiation exposure, hospital stay, and postoperative complications should also be considered for further studies in this area.