title: Use of navigation-assisted fluoroscopy to decrease radiation exposure during minimally invasive spine surgery.
abstract: BACKGROUND
  Minimally invasive surgery decreases postoperative pain and disability. However, limited views of the surgical field require extensive use of intraoperative fluoroscopy that may expose the surgical team to higher levels of ionizing radiation.
  
  
  OBJECTIVE
  To assess the feasibility and safety of navigation-assisted fluoroscopy during minimally invasive spine surgery.
  
  
  METHODS
  A combined cadaveric and human study comparing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) using navigation-assisted fluoroscopy with standard intraoperative fluoroscopy to determine differences in surgical times and radiation exposures.
  
  
  METHODS
  Eighteen fresh cadaveric spines underwent unilateral MIS TLIF by using either navigation-assisted fluoroscopy or standard fluoroscopy. Times for specific surgical steps were compared. In addition, a prospective short-term evaluation of the intraoperative and perioperative results of 10 patients undergoing navigation-assisted MIS TLIF (NAV group) compared with a retrospective review of 8 patients undergoing MIS TLIF performed by using standard fluoroscopy (FLUORO group).
  
  
  RESULTS
  In the cadaveric study, the times were similar between the NAV group and the FLUORO group for most key steps. No statistically significant differences were obtained for approach, exposure, screw insertion, facetectomy/decompression, or total surgical times. Statistically significant differences were obtained for the setup time and total fluoroscopy time. The setup time for the NAV group averaged 9.67 (standard deviation [SD], 3.74) minutes compared with 4.78 (SD, 2.11) minutes for the FLUORO group (p=.034). The total fluoroscopy time was higher for the FLUORO group compared with the NAV group (41.9 seconds vs. 28.7 seconds, p=.042). Radiation exposure was undetectable when navigation-assisted fluoroscopy is used (NAV group). In contrast, an average 12.4 milli-REM (mREM) of radiation exposure is delivered to the surgeon during unilateral MIS TLIF procedure without navigation (FLUORO group). In the clinical series, the total fluoro time for the NAV group was 57.1 seconds (SD, 37.3; range, 18-120) compared with 147.2 seconds (SD, 73.3; range, 73-295) for FLUORO group (p=.02). No statistically significant differences are noted for operating time, estimated blood loss, or hospital stay. No inadvertent durotomies, postoperative weakness, or new radiculopathy were noted in the NAV group. One inadvertent durotomy was encountered in the FLUORO group that was repaired intraoperatively without clinical sequelae.
  
  
  CONCLUSIONS
  The use of navigation-assisted fluoroscopy is feasible and safe for minimally invasive spine surgery. Radiation exposure is decreased to the patient as well as the surgical team.
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Diego VA Healthcare System, 200 West Arbor Drive #8894, San Diego, CA 92103 USA. ChollKim@ucsd.edu
authors.forename: Choll W
authors.initials: CW
authors.lastname: Kim
authors.forename: Yu-Po
authors.initials: YP
authors.lastname: Lee
authors.forename: William
authors.initials: W
authors.lastname: Taylor
authors.forename: Ahmet
authors.initials: A
authors.lastname: Oygar
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Kim
mesh_terms: D002102:Cadaver; D005240:Feasibility Studies; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D019060:Minimally Invasive Surgical Procedures; D011446:Prospective Studies; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control*; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods*; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery*; D025321:Surgery, Computer-Assisted