2013 Young Investigator Award Winner: How Safe Is Lateral Lumbar Interbody Fusion for the Surgeon? A Prospective In Vivo Radiation Exposure Study

Study Design. Prospective in vivo radiation exposure study. Objective. To assess surgeon exposure to ionizing radiation in the setting of lateral lumbar interbody fusion (LLIF). Summary of Background Data. Minimally invasive spine surgery relies heavily on image guidance. Rapid popularization of minimally invasive spine surgery procedures, such as LLIF, is appropriately accompanied by concern regarding occupational radiation exposure related to intraoperative fluoroscopy. Methods. Optically stimulated luminescence technology dosimeters were used to record radiation exposure prospectively at 5 anatomic locations during 18 LLIF procedures: (1) eye, (2) thyroid, (3) chest, (4) axilla, and (5) gluteal region. Additionally, a ring dosimeter was worn during 13 of the LLIF cases. Results. Average fluoroscopy time was 88.7 +/- 36.8 seconds and skin dose to the patient was 25.2 +/- 21.1 mGy. The chest dosimeter protected by lead recorded the lowest readings per procedure (0.44 +/- 0.49 mrem). The gluteal dosimeter recorded an average exposure of 2.31 +/- 4.50 mrem and the dosimeter at the axilla recorded an average of 4.20 +/- 7.76 mrem per procedure. Exposure to the thyroid and eye were 2.19 +/- 2.07 mrem and 2.64 +/- 2.76 mrem, respectively. With the exception of the gluteal region, dosimeter readings from all unprotected areas were significantly higher than those from the chest dosimeter (P < 0.0125). In the course of 13 procedures, 190 mrem of exposure to the hand was recorded by the ring dosimeters. More than 2700 LLIF procedures may be performed annually before occupational limits are exceeded. Conclusion. Prolonged exposure to "low-level" radiation as an occupational risk remains a concern for medical personnel. Radiation exposures to unprotected, radiosensitive locations, such as the axilla or eye, are worrisome. However, following radiation safety guidelines, 2700 LLIF procedures can be performed per year before exceeding occupational dose limits. Adherence to radiation safety guidelines is necessary to avoid sequelae related to an invisible but potentially deadly risk of minimally invasive spine surgery procedures.