Quantitative electrical pain threshold assessment in the lower urinary tract

Area of Science:

• Urology
• Neuroscience
• Pain Research

Background:

• Assessing pain perception in the lower urinary tract (LUT) is crucial for diagnosing various conditions.
• Electrical stimulation offers a method for semi-objective evaluation of sensory function in the LUT.
• Understanding the reliability and influencing factors of electrical pain threshold (PT) is essential for clinical application.

Purpose of the Study:

• To evaluate the reliability of electrical pain threshold (PT) measurements in the healthy lower urinary tract (LUT).
• To determine the impact of varying electrical stimulation frequencies on PT at different LUT locations.
• To compare PT between genders and identify influencing factors for accurate pain assessment.

Main Methods:

• Ninety healthy subjects (40 females, 50 males) underwent electrical stimulation at various LUT sites (bladder dome, trigone, urethra).
• Stimulation frequencies of 0.5 Hz, 1.1 Hz, and 1.6 Hz were used to assess current perception thresholds (CPTs), PTs, and tolerance thresholds over two visits.
• Data analysis involved linear mixed models, intraclass correlation coefficients (ICC), and Bland-Altman methods to assess reliability and variability.

Main Results:

• Pain thresholds (PTs) demonstrated variability based on stimulation frequency, anatomical location, and gender, with higher frequencies generally yielding lower PTs.
• The highest PTs were recorded at the bladder dome and membranous urethra, and males reported higher PTs than females.
• Reliability of PT assessments was good to excellent (ICC = 0.61–0.97) across most conditions, with exceptions in females at the bladder dome and distal urethra.

Conclusions:

• Electrical pain threshold (PT) assessments are safe and reliable in bladder and urethral locations.
• Semi-objective PT measurements can enhance understanding of LUT sensory afferents and complement urodynamic and CPT assessments.
• This methodology offers new diagnostic possibilities for precise, location-specific characterization of LUT pain and therapeutic response.