Application of pedicle screwing guider to severe spinal deformity

English Keywords:Pedicle screwing guider  Severe spinal deformity  Pedicle screw placement  Accuracy rate of screw placement

English Abstract:

  【Abstract】 Objectives: To explore the safety of 3D printed personalized pedicle screwing guiders for assisting screw placement during the operation of severe spinal deformity(Cobb angle of major curve ≥90°). Methods: Thirteen patients(9 females and 4 males) with severe spinal deformities who were treated with pedicle screwing guider technology from January 2017 to September 2017 in our hospital were retrospectively analyzed. Mean age at the time of surgery was 12.9±3.1 years, ranged from 10 to 19 years. Mean follow-up time was 13.8±1.9 months, ranged from 12 to 18 months. The placement of pedicle screws was evaluated by CT scans two weeks after surgery. According to the degree of pedicle screw breakthrough in the pedicle cortex, pedicle screw placement was divided into grade 0 (no breach), 1 (breach of ＜2mm), 2 (breach of 2-4mm) and 3 (breach ＞4mm), of which grade 0 and grade 1 were determined to be accurate. The preoperative and postoperative radiograph parameters including Cobb angle of major curve, kyphosis, coronal balance and sagittal vertebral axis were also measured and compared. Screw-related complications were recorded. Results: Assisted by 119 pedicle screwing guiders(238 pedicle guide holes), 232 pedicle screws were inserted successfully for the 13 patients with severe spinal deformity, and the success rate of assisted screw placement was 97.5%(232/238). According to the CT classification, the number of grade 0, 1, 2 and 3 was 111, 84, 33 and 4, and the accuracy rate of pedicle screw fixation was 84.1%(195/232). Two weeks after surgery, the Cobb angle of major curve was corrected from 110.6°±15.2° to 52.3°±16.2°(P＜0.05), and kyphosis was corrected from 58.3°±20.6° to 35.7°±10.4°(P＜0.05), coronal balance was corrected from 2.8±1.7cm to 1.7±0.5cm (P＜0.05), and sagittal vertebral axis was corrected from 3.1±1.8cm to 1.4±0.4cm(P＜0.05). No serious screw-related complication occurred. Conclusions: The pedicle screwing guider technology provides individualized navigation for patients with severe spinal deformity, which can achieve high accuracy of screw placement.