REPLY

Authors

  • Simon Podner


Sir,

There is a long lasting dispute about the physiological role of the prepuce in human. I see it as a tinny structure sitting at the evolutionary pinnacle, where our ‘selfish genes’ fight their way into the next generation. Competition here is harsh, with no room for redundancy. I see the prepuce as an ingenious device engineered to provide a strong sensory stimulation in a slippery environment of a copiously lubricated vagina. Evolution achieved this by the tubular prepuce sliding during sexual activity over the conically shaped glans as far as the frenulum allows. Both, the prepuce and the frenulum, have rich mechanoreceptor innervation [1] sending a large sensory input to the brain. The goal of this mechanism is to achieve maximum procreative efficiency of the semen by optimising ejaculation in place and time. To achieve this, the brain also needs to be finely tuned with the genital sensory structures.

Intuitively, removal of the penile most sensitive genital structure would lead not only to reduced sexual sensation [2], but also to more difficult achievement of ejaculation. This reasoning – named by Professor Boyle ‘common myth’– logically leads to a thought that circumcision might be a useful therapy for premature ejaculation (PE). In line with this, in my paper [3] I cited a report that found a reduction in PE in three of seven patients [4] circumcised due to different penile pathology (e.g., phimosis, balanitis, condyloma, etc.). However, I have to admit that these penile conditions made this empirical support unconvincing. Professor Boyle, by contrast, cites studies showing higher frequency of PE [5] and shorter intravaginal ejaculation latency time (IELT) [6] in circumcised men. Of these, higher frequency of PE in the circumcised seems more convincing, as no effect of circumcision status on IELT could be found in an international study after the exclusion of Turkey [6]. Islamic or Asian background was suggested to be a risk factor for PE irrespective of circumcision status [7]. Nevertheless, anything but lower frequency of PE and longer IELT in the circumcised sounds contra intuitive, and needs explanation. The answer, I believe, is neuroplasticity – changes in the thresholds and connectivity that occur within the CNS after circumcision.

The method of the penilo-cavernosus reflex elicitation I used in my study [3] indeed activated only deep pressure and pain receptors [8] in the glans in the circumcised men. By contrast, in the intact men, the Meisners' corpuscles [9] within the foreskin were also stimulated. However, I do not share the opinion of Professor Boyle that this reduces validity of my clinical findings. In both, the intact and circumcised men, I activated all the available sensory receptors at the tip of the penis, and I showed unequivocal differences in the elicitability of the penilo-cavernosus reflex in the two populations of men [3]. The finding is relevant both for using the reflex as a clinical test, and also for demonstration of possible functional differences. During sexual activity both the glans and the overlying foreskin are stimulated in intact men, as discussed above. However, I do agree that using this approach I could not differentiate absence of Meisners' corpuscles in the foreskin or desensitisation of deep pressure and pain receptors in the glans as the reason for the reduced reflex elicitability found in the circumcised men.