Bone-Mounted Robotic System in Minimally Invasive Spinal Surgery for Osteoporosis Patients: Clinical and Radiological Outcomes

Yu-Feng Su,1,2 Tai-Hsin Tsai,1,3 Ann-Shung Lieu,1,3,4 Chih-Lung Lin,1– 3 Chih-Hui Chang,1,2 Cheng-Yu Tsai,4– 6 Hui-Yuan Su1,3 1Division of Neurosurgery, Department of Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan; 2Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 3Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 4Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 5Ph.D. Program in Environmental and Occupational Medicine, College of Medicine, Kaohsiung Medical University and National Health Research Institutes, Kaohsiung, Taiwan; 6Post Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, TaiwanCorrespondence: Cheng-Yu Tsai; Hui-Yuan Su, Division of Neurosurgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100 Tzyou 1st Road, Kaohsiung, 80708, Taiwan, Tel +886-7-3215049, Fax +886-7-3215039, Email moutzyy691010@yahoo.com.tw; latimeria8@hotmail.comPurpose: Severe complications, including screw loosening events and low fusion rates, in spinal fusion surgery using the traditional open method are problematic. This retrospective study aimed to evaluate the rate of screw loosening and the clinical outcomes of bone-mounted miniature robot-assisted pedicle screw placement in patients treated for degenerative spinal disease.Patients and Methods: Data were collected from the medical records of 118 patients (mean age, 69 years). Differences in clinical outcomes, including the Oswestry disability index, visual analog scale score, screw loosening rate, cage fusion rate, and complications, were evaluated among different bone mineral densities.Results: The screw loosening and cage fusion rates for all patients, normal bone mineral density, osteopenia, and osteoporosis groups were 12%, 8.6%, 13.1%, and 14%, respectively, and 85.3%, 93%, 82.5%, and 81.4%, respectively. There was a higher screw loosening rate and a lower cage fusion rate in the osteopenia and osteoporosis groups than in the normal bone density group. The accuracy of the screw placement was 97.3%. There were no statistically significant differences in the Oswestry disability index and visual analog scale scores, and no major complications for dural tear or vascular or visceral injury.Conclusion: Our study demonstrated an acceptable screw loosening rate in patients with osteoporosis compared to that in patients with normal bone mineral density. The robotic system resulted in accurate screw placement in patients with osteoporosis.Keywords: robotic surgery, screw loosening rate, spinal fixation, spinal fusion, spinal fusion rate