Clinical Evidence eGuide O-arm® Imaging System

Park P, Foley KT, Cowan JA, Marca FL. Department of Neurosurgery, University of Michigan Health System, Ann Arbor, MI, USA Surg Neurol Int. 2010 Aug Background: Pedicle screw misplacement is relatively common, with reported rates ranging up to 42%. Although computer-assisted image guidance (CaIG) has been shown to improve accuracy in open spinal surgery, its use in minimally invasive procedures has not been as well evaluated. We present our technique and review the results from a cohort of patients who underwent minimally invasive lumbar pedicle screw placement utilizing the O-arm imaging unit in conjunction with the StealthStation Treon System. Methods: A retrospective review of patients who underwent minimally invasive pedicle screw fixation with CaIG was performed. Eleven consecutive patients were identified and all were included. Nine patients underwent a single-level transforaminal lumbar interbody fusion. Two patients underwent multi-level fusion. Inaccurate pedicle screw placement was determined by postoperative computed tomography (CT) and graded as 0-2, 2-4, 4-6, or 6-8 mm. Results: A total of 52 screws were placed. Forty screws were inserted in eight patients who had postoperative CT, and a misplacement rate of 7.5% was noted including one lateral and two medial breaches. All breaches were graded as 0-2 mm and were asymptomatic. In the remaining three patients, post-instrumentation O-arm imaging did not demonstrate pedicle screw misplacement. Conclusion: Although this initial study evaluates a relatively small number of patients, minimally invasive pedicle screw fixation utilizing the O-arm and StealthStation for CaIG appears to be safe and accurate. An assistive image-guided surgical robot system using o-arm fluoroscopy for pedicle screw insertion: preliminary and cadaveric study. Abstract Kim S, Chung J, Yi BJ, Kim YS. Hanyang University, Seoul. Kyushu University, Fukuoka, JapanKim S, Chung J, Yi BJ, Kim YS. Hanyang University, Seoul. Kyushu University, Fukuoka, Japan Neurosurgery. 2010 Dec Background: The biplane fluoroscopy guided robot system (BFRS) was developed for surgical robotic systems, minimally invasive surgeries, and cooperative robotic systems, as well as enhanced surgical planning and navigation with preoperative and intraoperative image data. Objective: To propose a novel surgical robot system for percutaneous pedicle screw insertion. Methods: The BFRS consists of an O-shaped biplane fluoroscope (O-arm), a surgical planning and operating system, and an assistive robot. Each part of the BFRS has a role in conducting percutaneous pedicle screw placements. To evaluate BFRS accuracy, each part was analyzed, and to assess the safety and feasibility of percutaneous pedicle screw insertions with the BFRS, cadaveric studies involving 14 levels in the thoracic and lumbar spine regions were conducted on 2 cadavers. Results: Errors in each part of the system and within the entire system were evaluated. The accuracy of generating coordinates using O-arm images was 0.30 ± 0.15 mm. The robot demonstrated a duplication value of 4.97 μm RMS and an accuracy of 0.358 mm RMS. Total system error was 1.38 ± 0.21 mm. The results of the cadaveric studies show that inserted pedicular screws were adequately located within the spine with no unexpected malpositioning of the screws. The axial angle difference between planned and postoperative data was 2.45 ± 2.56°, and the sagittal angle difference was 0.71 ± 1.21°. Conclusion: The BFRS might be helpful in improving the accuracy of percutaneous pedicular screw insertion procedures. In the future, we will attempt to improve the accuracy and reliability of the BFRS and to determine new clinical applications for the BFRS. Minimally invasive image-guided direct repair of bilateral L-5 pars interarticularis defects.