Benefits of inferential statistical methods in radiation exposure studies: another look at percutaneous spinal cord stimulation mapping [trialing] procedures observational study

Wininger KL – Radiation exposure levels in spinal cord stimulation (SCS) trialing procedures remain negligible. While no differences in fluoroscopy times for such procedures were detected based on physician experience, the expert implanter demonstrated the ability to use less fluoroscopy time than that of the benchmark reference level.

Methods

• An observational study.
• A non–university outpatient Interventional Pain Management practice in the United States.
• Fluoroscopy time (in seconds) was retrospectively studied in 18 SCS trialing procedures (with dual lead placement in the low thoracic spine) performed over a 3–month period.
• The procedures were categorized by physician experience: one novice physician implanter with n = 5 cases and one expert physician implanter with n = 13 cases.
• All procedures were conducted with the same fluoroscope operator and the same mobile C–arm fluoroscopy system.
• A two–tailed t–test was used to compare mean fluoroscopy times between physician categories.
• Left–tailed t–tests were used to compare mean fluoroscopy times for each physician category separately to the benchmark level (μ = 71.7 seconds).
• Incident air kerma (KERMA) was assessed by nonsimplistic modeling.

Results

• No statistical difference was found in mean fluoroscopy times for SCS trialing procedures between the novice– and expert–implanter, novice = 63.5 seconds and expert = 53.9 seconds.
• In the case of the novice implanter, although mean fluoroscopy time was lower than the benchmark reference level, novice = 63.5 seconds compared to μ = 71.7 seconds, this was not significantly relevant.
• In the case of the expert implanter, a statistically relevant reduction in mean fluoroscopy time was observed compared to the benchmark level, expert = 53.9 seconds versus μ = 71.7 seconds.
• KERMA ranged from 5.3 mGy to 9.1 mGy with a mean and standard deviation of 6.5 mGy and 1.5 mGy, respectively, in the novice implanter sample set.
• KERMA ranged from 2.6 mGy to 13.1 mGy with a mean and standard deviation of 5.8 mGy and 3.2 mGy, respectively, in the expert implanter sample set.

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