LAUSR

OBJECTIVE This study sought to; 1) describe the use 'K-wireless' pedicle screw insertion among adults (age ≥ 18) undergoing a minimally-invasive fusion and 2) perform a systematic review (SR) of all studies that describe a navigated, 'K-wireless' technique with 3D fluoroscopy. METHODS Patients undergoing a minimally invasive fusion requiring pedicle screw fixation for any indication were prospectively enrolled in the observational component of this study. An assessment of pedicle breach was performed independently and in duplicate based on a modification of the Belmont grading scale. Articles for the SR were identified from a structured search of MEDLINE from inception to 05/08/2019 without restriction of language. RESULTS A total of 82 pedicle screws were placed in 20 patients who underwent surgery between January and June 2014. There was no significant difference in mean operative time between the cases included in this study and a matched cohort of 20 patients undergoing surgery with 2D-fluoroscopy and K-wire assisted pedicle screw placement (95±13mins vs 87±20mins; p>0.05). There were two major pedicle breaches (Belmont grade 3) in a single patient, yielding a major breach rate of 2.44%. A total of six articles that described the placement of 700 pedicle screws in 160 patients between May 2011 and March 2017 were included in the SR. The overall breach rate was 7.00% (n=37). CONCLUSIONS Percutaneous pedicle screws can be placed accurately and safely using three-dimensional navigation without the use of K-wires and may confer benefits to patients and clinicians by reducing K-wire associated complications and radiation exposure.