Accuracy Of Percutaneous Screw Placement Research Articles

3D - Navigated percutaneous screw fixation of pelvic ring injuries – a pilot study

IntroductionScrew fixation of pelvic ring fractures is a common, but demanding procedure and navigation techniques were introduced to increase the precision of screw placement. The purpose of this case series is to demonstrate a lower screw malposition rate using percutaneous fixation of pelvic ring fractures and sacroiliac dislocations guided by navigation system based on 3D-fluoroscopic images compared to traditional imaging techniques and to evaluate the functional outcomes of this innovative procedure. Patient and Methods10 cases of disrupted pelvic ring lesions treated in our hospital from February 2018 to December 2018 were included for closed reduction and percutaneous screw fixation of using with O-Arm and the acquisition by the Navigator. Preoperative assessment was performed on the patients by means of X Ray imaging and CT scan. Routine CT was carried out on third postoperative day to evaluate screw placement. Measures of radiation exposure were extracted directly from reports provided by system. Quality of life was evaluated by SF 36-questionnaire 6 months after surgery. Results12 iliosacral- and 2 ramus pubic-screws were inserted. In post-operative CT-scans the screw position was assessed and graded using the score described by Smith. No wound infection or iatrogenic neurovascular damage were observed. No re-operations were performed. The exposure to radiation is, for the patient, slightly greater than that resulting from the use of traditional fluoroscopic systems, while it is naught for the surgical team, which at the time of image acquisition is located outside the room. Discussion and ConclusionThe execution of an intraoperative 3D-fluoroscopic scan can on its own suffice as a post-operative control examination since its accuracy is similar to that of the post-operative CT. The use of a navigated 3d fluoroscopy exposes the patient to an amount of radiation slightly greater than that of traditional fluoroscopy, but the dose is lower than a CT examination. For the operating team, exposure to radiation is naught. 3D-fluoroscopic navigation is a safe tool providing high accuracy of percutaneous screw placement for pelvic ring fractures. Finally, despite the small cohort of patients studied, the excellent results obtained regarding the patients' quality of life and the absence of complications allow us to look positively at the future of this technique, which needs further studies and improvement.

Percutaneous pedicle screw placement in the thoracic spine: A cadaveric study

Study Design:A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance.Summary of Background Data:While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance.Materials and Methods:Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior–posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate.Results:Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96.Conclusions:This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.

2D-fluoroscopic navigated percutaneous screw fixation of pelvic ring injuries - a case series

BackgroundScrew fixation of pelvic ring fractures is a common, but demanding procedure and navigation techniques were introduced to increase the precision of screw placement. The purpose of this case series was the evaluation of screw misplacement rate and functional outcome of percutaneous screw fixation of pelvic ring disruptions using a 2D navigation system.MethodsBetween August 2004 and December 2007, 44 of 442 patients with pelvic injuries were included for closed reduction and percutaneous screw fixation of disrupted pelvic ring lesions using an optoelectronic 2D-fluoroscopic based navigation system. Operating and fluoroscopy time were measured, as well as peri- and postoperative complications documented. Screw position was assessed by postoperative CT scans. Quality of live was evaluated by SF 36-questionnaire in 40 of 44 patients at mean follow up 15.5 ± 1.2 month.Results56 iliosacral- and 29 ramus pubic-screws were inserted (mean operation time per screw 62 ± 4 minutes, mean fluoroscopy time per screw 123 ± 12 seconds). In post-operative CT-scans the screw position was assessed and graded as follows: I. secure positioning, completely in the cancellous bone (80%); II. secure positioning, but contacting cortical bone structures (14%); III. malplaced positioning, penetrating the cortical bone (6%). The malplacements predominantly occurred in bilateral overlapping screw fixation. No wound infection or iatrogenic neurovascular damage were observed. Four re-operations were performed, two of them due to implant-misplacement and two of them due to implant-failure.Conclusion2D-fluoroscopic navigation is a safe tool providing high accuracy of percutaneous screw placement for pelvic ring fractures, but in cases of a bilateral iliosacral screw fixation an increased risk for screw misplacement was observed. If additional ramus pubic screw fixations are performed, the retrograde inserted screws have to pass the iliopubic eminence to prevent an axial screw loosening.

An Evaluation of Image-Guided Technologies in the Placement of Percutaneous Iliosacral Screws

A surgical simulation study in human cadaver spine specimens was conducted to evaluate the accuracy of 3 different surgical navigation systems compared to standard fluoroscopy in the percutaneous placement of iliosacral screws. To compare the accuracy of percutaneous iliosacral screw placement using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance (Medtronic Surgical Navigation Technologies, Louisville, CO), and electromagnetic fluoroscopic image guidance. Conventional percutaneous sacroiliac screw placement has a malposition rate as high as 15%, as reported in the English-speaking literature (Hinsche et al [Clin Orthop Relat Res 2002;395:135-44] and Templeman et al [Clin Orthop Relat Res 1996;329:194-8]). Iso-C3D and computer-assisted image guidance technologies have been proposed to increase this accuracy rate. Two iliosacral screws were placed bilaterally (4 screws) in each of 4 cadavers using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance, and electromagnetic fluoroscopic image guidance. Screw positions were analyzed by computerized tomography after instrumentation and assigned a score based on deviation from ideal screw position. The StealthStation with FluoroNav (Medtronic Surgical Navigation Technologies) appeared to provide the highest accuracy of all guidance techniques. This result was more accurate than standard fluoroscopy. Computer-assisted fluoroscopy based image navigation appears to be more accurate than standard fluoroscopy in placing these screws. However, errors may occur with all techniques. Further refinement in registration procedures may highly improve the accuracy of percutaneous screw placement in a variety of spinopelvic procedures.