Accuracy of K-Wireless Insertion of Percutaneous Pedicle Screws Using Computer-Assisted Spinal Navigation: A Systematic Review and Single-Center Experience

This study sought to 1) describe the use K-wireless pedicle screw insertion among adults (age ≥18 years) undergoing a minimally invasive fusion and 2) perform a systematic review (SR) of all studies that describe a navigated, K-wireless technique with 3-dimensional fluoroscopy. 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 May 8, 2019, without restriction of language. 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 2-dimensional fluoroscopy and K-wire–assisted pedicle screw placement (95 ± 13 vs. 87 ± 20 minutes, respectively; P > 0.05). There were 2 major pedicle breaches (Belmont grade 3) in a single patient, yielding a major breach rate of 2.44%. A total of 6 papers 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). Percutaneous pedicle screws can be placed accurately and safely using 3-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.