J Korean Neurosurg Soc.  2021 Nov;64(6):933-943. 10.3340/jkns.2020.0338.

Reduction of Radiation Exposure by Modifying Imaging Manner and Fluoroscopic Settings during Percutaneous Pedicle Screw Insertion

• Kim HJ
• Park ES
• Lee SH
• Park CH
• Chung SW

• KMID: 2521983
• DOI: http://doi.org/10.3340/jkns.2020.0338

Abstract

Objective
: Percutaneous pedicle screw (PPS) fixation is a needle based procedure that requires fluoroscopic image guidance. Consequently, radiation exposure is inevitable for patients, surgeons, and operation room staff. We hypothesize that reducing the production of radiation emission will result in reduced radiation exposure for everyone in the operation room. Research was performed to evaluate reduction of radiation exposure by modifying imaging manner and mode of radiation source.
Methods
: A total of 170 patients (680 screws) who underwent fusion surgery with PPS fixation from September 2019 to March 2020 were analyzed in this study. Personal dosimeters (Polimaster Ltd.) were worn at the collar outside a lead apron to measure radiation exposure. Patients were assigned to four groups based on imaging manner of fluoroscopy and radiation modification (pulse mode with reduced dose) : continuous use without radiation modification (group 1, n=34), intermittent use without radiation modification (group 2, n=54), continuous use with radiation modification (group 3, n=26), and intermittent use with radiation modification (group 4, n=56). Post hoc Tukey Honest significant difference test was used for individual comparisons of radiation exposure/screw and fluoroscopic time/screw.
Results
: The average radiation exposure/screw was 71.45±45.75 μSv/screw for group 1, 18.77±11.51 μSv/screw for group 2, 19.58±7.00 μSv/screw for group 3, and 4.26±2.89 μSv/screw for group 4. By changing imaging manner from continuous multiple shot to intermittent single shot, 73.7% radiation reduction was achieved in the no radiation modification groups (groups 1, 2), and 78.2% radiation reduction was achieved in the radiation modification groups (groups 3, 4). Radiation source modification from continuous mode with standard dose to pulse mode with reduced dose resulted in 72.6% radiation reduction in continuous imaging groups (groups 1, 3) and 77.3% radiation reduction in intermittent imaging groups (groups 2, 4). The average radiation exposure/screw was reduced 94.1% by changing imaging manner and modifying radiation source from continuous imaging with standard fluoroscopy setting (group 1) to intermittent imaging with modified fluoroscopy setting (group 4). A total of 680 screws were reviewed postoperatively, and 99.3% (675) were evaluated as pedicle breach grade 0 (<2 mm).
Conclusion
: The average radiation exposure/screw for a spinal surgeon can be reduced 94.1% by changing imaging manner and modifying radiation source from real-time imaging with standard dose to intermittent imaging with modified dose. These modifications can be instantly applied to any procedure using fluoroscopic guidance and may reduce the overall radiation exposure of spine surgeons.

Keyword

Radiation dosage; Minimally invasive surgical procedures; Pedicle screw; Radiation exposure; Fluoroscopy

Figure

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  Fig. 1. Flow-chart of classification criteria for groups 1, 2, 3, and 4. Patients were grouped based on radiation modification and imaging manner.

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  Fig. 2. Anteroposterior (A) and lateral (B) images were obtained after K-wire placement followed by rod insertion (C) using continuous mode with standard dose fluoroscopy. After modifying radiation source to pulse mode with reduced dose, image quality decreased slightly (D-F).

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  Fig. 3. Three anatomic features interfere with percutaneous pedicle screw insertion. Rigid sclerosis with high bone density on preoperative computed tomography is visible on left L4 pedicle and vertebral body (white arrow) (A). Pedicle with vertical diameter of 5.3 mm is visible on left L5 peidcle (white arrow) (B). Bilateral facet joint hypertrophy is visible on both L4–5 facet joints (white arrow) (C).

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  Fig. 4. Results of post-hoc comparisons using Tukey Honest significant difference test. Surgeon radiation exposure per screw is expressed in microsieverts (A), and fluoroscopic time per screw is expressed in seconds (B).

Reference

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