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  • Accuracy and Safety of Minimally Invasive Guidewireless, Navigated Pedicle Screw Placement

    Final Number:

    Brandon W Smith MD MSCR; Jacob R. Joseph MD; Michael Kirsch; M. Oakley Strasser; Jacob G Smith; Paul Park MD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2017 Annual Meeting

    Introduction: Percutaneous pedicle screw insertion (PPSI) has been a mainstay of minimally invasive spinal surgery. Traditionally, PPSI is a fluoroscopy guided, multi-step process involving traversing the pedicle with a jamshidi needle, placement of a kirschner wire (K-wire), placement of soft tissue dilator, pedicle tract tapping, screw insertion over the K-wire. This study evaluates the accuracy and safety of PPSI with a simplified two-step process using a navigated awl-tap followed by navigated screw insertion without use of fluoroscopy.

    Methods: Patients undergoing PPSI utilizing the k-wireless technique were identified. Data were extracted from the electronic medical record. Complications associated with screw placement were recorded. Post-operative x-rays as well as CT were evaluated for accuracy of pedicle screw placement.

    Results: 36 patients were included. There were 18 (50%) women with mean age of 60.4yrs (23.8-78.4) and mean BMI was 28.5kg/m^2(20.8-40.1). A total of 238 pedicle screws were placed. A mean of 6.6(4-14) pedicle screws were placed over a mean of 2.61(1-7) levels. Post-operative x-rays did not identify any pedicle breaches. In subgroup analysis of 25/36(69%) patients who underwent CT, 173 screws were assessed with 170(98.3%) completely within the pedicle and 3(1.7%) which demonstrated mild medial, grade B, breaches. There were no complications related to PPSI in this cohort.

    Conclusions: This streamlined 2-step guidewireless, navigated PPSI appears safe and accurate without the need for radiation exposure to surgeon and staff.

    Patient Care: The navigated awl-tap safely and accurately allows PPSI. Use of this simplified navigated technique will potentially allow a more efficient and safe surgery for the patient.

    Learning Objectives: By the conclusion of this session participants should be able to: a) describe that Percutaneous pedicle screws can safely and accurately be placed without use of a K-wire in a more efficient 2-step process without need for radiation exposure to surgeon and staff.


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