Comparison of radiation exposure and surgery time between an intraoperative CT with automatic surface registration and a preoperative CT with manual surface registration in navigated spinal surgeries

Purpose This retrospective matched case–control study was conducted to compare two CT based surgery techniques for navigated screw placement in spinal surgery, whether a reduction of radiation exposure and surgery time could be achieved. Methods We matched cases treated with an intraoperative CT (iCT), regarding the type and number of implants, with cases treated with a preoperative CT (pCT) of one main surgeon. Outcome measures were radiation exposure due to intraoperative control x-rays, radiation exposure due to CT images, and the duration of surgery. Results The required radiation exposure could be significantly reduced in the iCT group. For the intraoperative control X-rays by 69% (median (MED) 88.50/standard deviation (SD) 107.84 and MED 286.00/SD 485.04 for iCT and pCT respectively—in Gycm 2 ; p