Intraoperative computed tomography with integrated navigation in percutaneous iliosacral screwing
ABSTRACT BACKGROUND: Iliosacral screw fixation has generally been accepted as a treatment for unstable pelvic fractures with posterior sacroiliac joint disruption despite a 2-16% rate of screw malposition. The integration of an intraoperative computed tomography (iCT) with a navigation system was utilized in percutaneous sacroiliac screwing to provide an alternative. METHODS: From October 2010 to November 2011, thirteen patients presented pelvic fractures with posterior ring disruption (lateral compression type 2-3 [n=12] and vertical shear type [n=1] by Young-Burgess Classification) and underwent percutaneous iliosacral screwing using an iCT integrated with navigation system. The perioperative data and radiographic outcomes of the patients were collected and analyzed. RESULTS: Navigation times ranged from 10 to 45min (mean of 21.2±10.6min). Radiation exposure to the skin utilizing integrated navigation system ranged from 23.5 to 28.1mGy (mean of 26.4±1.5mGy), and the dose associated with examining the screw position ranged from 22.5 to 26.8mGy (mean of 25.5±1.1mGy). Effective dose of radiation ranged from 9.26 to 17.43mSv (mean of 13.16±2.52mSv). The iCT demonstrated iliosacral screws in adequate position (i.e., no penetration or encroachment of the neuroforamen or cord). No neurologic or vascular injury occurred in these cases. CONCLUSIONS: An iCT with an integrated navigation system provided accuracy for percutaneous iliosacral screwing. In addition, the accumulated dose was minimized for surgeons. However, effective dose of radiation in iCT with an integrated navigation system group was higher than fluoroscopic-assisted iliosacral screwing in hands of the same group of surgeons. No neurologic complications occurred. The iCT with an integrated navigation system provided an alternative to percutaneous iliosacral screwing.
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ABSTRACT: Background Percutaneous iliosacral screw insertion requires substantial experience and detailed anatomical knowledge to find the proper entry point and trajectory even with the use of a navigation system. Our hypothesis was that three-dimensional (3D) fluoroscopic navigation combined with a preoperative computed tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion. The purpose of the current study is two-fold: 1) to demonstrate the navigation accuracy for sacral fractures and sacroiliac dislocations on widely displaced cadaveric pelves; and 2) to report the technical and clinical aspects of percutaneous iliosacral screw insertion using the CT-3D-fluoroscopy matching navigation system. Methods We simulated three types of posterior pelvic ring disruptions with vertical displacements of 0, 1, 2 and 3 cm using cadaveric pelvic rings. A total of six fiducial markers were fixed to the anterior surface of the sacrum. Target registration error over the sacrum was assessed with the fluoroscopic imaging center on the second sacral vertebral body. Six patients with pelvic ring fractures underwent percutaneous iliosacral screw placement using the CT-3D-fluoroscopy matching navigation. Three pelvic ring fractures were classified as type B2 and three were classified as type C1 according to the AO-OTA classification. Iliosacral screws for the S1 and S2 vertebra were inserted. Results The mean target registration error over the sacrum was 1.2 mm (0.5 to 1.9 mm) in the experimental study. Fracture type and amount of vertical displacement did not affect the target registration error. All 12 screws were positioned correctly in the clinical series. There were no postoperative complications including nerve palsy. The mean deviation between the planned and the inserted screw position was 2.5 mm at the screw entry point, 1.8 mm at the area around the nerve root tunnels and 2.2 mm at the tip of the screw. Conclusion The CT-3D-fluoroscopy matching navigation system was accurate and robust regardless of pelvic ring fracture type and fragment displacement. Percutaneous iliosacral screw insertion with the navigation system is clinically feasible.Injury 06/2014; 45(6). DOI:10.1016/j.injury.2014.01.015 · 2.46 Impact Factor
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ABSTRACT: The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. 100 guidewires and hollow titan screws were inserted in 38 patients (49.6±19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. The mean minimal distance between guidewire and adjacent neural foramina was 4.5±2.01mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6±0.53mm to 1.2±0.54mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7mGycm). The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.European Journal of Radiology 02/2015; 84(2):290-4. DOI:10.1016/j.ejrad.2014.11.017 · 2.16 Impact Factor