Background The pedicle screw is one of the main tools used in spinal deformity correction surgery. Robotic and navigated surgeries are usually used, and they provide superior accuracy in pedicle screw placement than free-hand and fluoroscopy-guided techniques. However, their high cost and space limitation are problematic. We provide a new solution using 3D printing technology to facilitate spinal deformity surgery. Methods A workflow was developed to assist spinal deformity surgery using 3D printing technology. The trajectory and profile of pedicle screws were determined on the image system by the surgical team. The engineering team designed drill templates based on the bony surface anatomy and the trajectory of pedicle screws. Their effectiveness and safety were evaluated during a preoperative simulation surgery. The surgery consisted in making a pilot hole through the drill template on a computed tomography- (CT-) based, full-scale 3D spine model for every planned segment. Somatosensory evoke potential (SSEP) and motor evoke potential (MEP) were used for intraoperative neurophysiological monitoring. Postoperative CT was obtained 6 months after the correction surgery to confirm the screw accuracy. Results From July 2015 to November 2016, we performed 10 spinal deformity surgeries with 3D printing technology assistance. In total, 173 pedicle screws were implanted using drill templates. No notable change in SSEP and MEP or neurologic deficit was noted. Based on postoperative CT scans, the acceptable rate was 97.1% (168/173). We recorded twelve pedicle screws with medial breach, six with lateral breach, and five with inferior breach. Medial breach (12/23) was the main type of penetration. Lateral breach occurred mostly in the concave side (5/6). Most penetrations occurred above the T8 level (69.6%, 16/23). Conclusion 3D printing technology provides an effective alternative for spinal deformity surgery when expensive medical equipment, such as intraoperative navigation and robotic systems, is unavailable.

Background The aim of this study is to introduce a new method of percutaneous endoscopic decompression under 3D real-time image-guided navigation for spinal stenosis in degenerative kyphoscoliosis patients without instability or those who with multiple comorbidities. Decompression alone using endoscope for kyphoscoliosis patient is technical demanding and may result in unnecessary bone destruction leading to further instability. The O-arm/StealthStation system is popular for its ability to provide automated registration with intraoperative, postpositioning computed tomography (CT) which results in superior accuracy in spine surgery. Methods In this study, we presented four cases. All patients were over seventy years old female with variable degrees of kyphoscoliosis and multiple comorbidities who could not endure major spine fusion surgery. Percutaneous endoscopic unilateral laminotomy and bilateral decompression under 3D real-time image-guided navigation were successfully performed. Patients’ demographics, image study parameters, and outcome measurements including pre- and post-operative serial Visual analog scale (VAS), and Oswestry Disability Index (ODI) were well documented. The follow-up time was 1 year. Results Pre- and post-operative MRI showed average dural sac cross sectional area (DSCSA) improved from 81.62 (range 67.34–89.07) to 153.27 (range 127.96–189.73). Preoperative neurological symptoms including radicular leg pain improved postoperatively. The mean ODI (%) were 85 (range 82.5–90) at initial visit, 35.875 (range 25–51) at 1 month post-operatively, 26.875 (range 22.5–35) at 6 months post-operatively and 22.5 (range 17.5–30) at 12 months post-operatively (p < 0.05). The mean VAS score were 9 (range 8–10) at initial visit, 2.25 (range 2–3) at 1 month post-operatively, 1.75 (range 1–2) at 6 months post-operatively and 0.25 (range 0–1) at 12 months post-operatively (p < 0.05). There was no surgery-related complication. Conclusions To the best of our knowledge, this is the first preliminary study of percutaneous endoscopic laminotomy under O-arm navigation with successful outcomes. The innovative technique may serve as a promising solution in treating spinal stenosis patients with lumbar kyphoscoliosis and multiple comorbidities.