ESTABLISHING NORMAL PENILE SKIN SENSATION USING TWO-POINT DISCRIMINATION TEST

Abstract

Introductions: To many penile surgeries, degloving of the penis is a routine part. The effect of this on penile sensation is unknown. The Two-Point Discrimination test (TPD) is used in clinical practice to evaluate sensory nerve function. There is no normative data for two-point discrimination sensation in the penile skin in children. Methods: Participants were prospectively collected from the pediatric surgical clinic patients provided they were: 7 years or older, generally healthy with no known systemic or neurological disease, had no prior genitourinary surgery or trauma, and demonstrated understanding of the test principle on the fingers. Lowest TPD test was recorded for the following areas: dorsum of penis, ventral surface of penis, pubic skin, scrotum and medial thigh. The test was started at 5 mm and incrementally increased by 1-2 mm until the child could reliably feel two separate touch points by giving correct responses 4 out of 5 or 7 out of 10 times for each area. Data was analysed using mean +/- standard deviation. Results: 24 patients were enrolled during the study period August 2021 - October 2022, mean age 10 +/-2.1 years. TPD for dorsal and ventral penile skin was 8.5 +/-1 mm. For the scrotum, pubic skin and medial thigh; TPD was 9.9 +/-1.6, 10.3 +/-1.8 and 14 +/- 2.4 mm; respectively. Conclusion: Normal TPD for the penile skin is around 8 mm. This will aid in studying sensory effects of penile surgery, particularly degloving penile skin.