Patient dose in fluoroscopically guided cervical discectomy and fusion

Cervical discectomy and fusion (CDF) is a minimally invasive procedure, where the accurate placement of the implants is accomplished using fluoroscopic guidance. Therefore, the evaluation of the radiation dose becomes mandatory. The purpose of the current study was to assess patient dose during fluoroscopically guided anterior and/or posterior CDF procedures. Thirty-three patients undergoing single or multiple-level CDF were studied using a mobile C-arm system. Data regarding fluoroscopy time (FT), air kerma area product (KAP) and cumulative dose (CD) were recorded. Patient entrance surface dose (ESD), thyroid absorbed dose and effective dose (ED) were calculated from KAP measurements, utilizing the CALDoseX software. The average FT was 0.12 min (range 0.02-0.48 min), resulting to a KAP value of 0.21 Gy cm² (range 0.01-1.46 Gy cm² ) and a CD value of 0.96 mGy (range 0.04-6.58 mGy). The ESD ranged between 0.08 and 13.58 mGy (average 1.95 mGy), the ED between 0.001 and 0.097 mSv (average 0.015 mSv), while the dose absorbed by the thyroid ranged between 0.01 and 1.12 mGy (average 0.194 mGy). The dose associated with the CDF procedure is very low, comparable to that delivered by a lateral X-ray radiograph of the cervical spine. However, higher doses can be revealed, due to the non-optimum use of the X-ray system and extended FTs, mainly affected by complex clinical conditions, as well as the experience of the neurosurgeon. Additional studies need to be conducted for further investigation of the patient dose from the CDF procedure. (authors)