Radiation Exposure During Fluoroscopically-Assisted Pedicle Screw Insertion

Yoga R. Rampersaud, MD
Kevin T. Foley, MD (Memphis, TN)
Alfred C. Shen, MD (San Bernardino, CA)
Scott Williams, MD, PhD
Milo Solomito, PhD (Memphis, TN)

Introduction:

The purpose of this study was to assess radiation exposure to the spine surgeon during fluoroscopically–assisted thoracolumbar pedicle screw placement. To our knowledge, no prior study has assessed fluoroscopy–related radiation exposure to spine surgeons.

Methods:

Bilateral pedicle screw placement (T11–S1) was performed in six fresh cadavers using standard techniques and fluoroscopic imaging. Radiation dose rates to the surgeon's neck, torso, and dominant hand were measured with dosimeter badges and thermolucent dosimeter (TLD) rings. Radiation levels were quantified at various distances from the dorsal lumbar surface in three cadavers using an ion chamber radiation survey meter along a spatial grid.

Results:

The mean dose rate to the neck was 8.3 mrem/min. The dose rate to the torso was greatest when the surgeon was positioned ipsilateral to the beam source (53.3 mrem/min, compared to 2.2 mrem/min on the contralateral side). The average hand dose rate was 58.2 mrem/min. A significant increase (1.5 to 2 times) in hand dose rate was associated with placement of screws ipsilateral to the x–ray beam source (p=0.0005) and larger specimens (p=O.0007). Radiation levels significantly decreased as distance from the x–ray beam source and
dorsal body surface increased. The greatest levels of radiation (Compton scatter) were noted on the side where the primary x–ray beam entered the cadaver.

Discussion:

Fluoroscopically–assisted pedicle screw placement exposes the spine surgeon to significantly greater radiation levels than other, non–spinal musculoskeletal procedures involving the use of a fluoroscope. In fact, dose rates are up to 10–12 times greater. Consequently, spine surgeons performing fluoroscopically–assisted thoracolumbar procedures should monitor their annual radiation exposure. Measures to reduce radiation exposure during these procedures are certainly called for.