The frequency of undescended testis from birth to adulthood: a review

Abstract

Dear Sir, I read the article titled ‘The frequency of undescended testis from birth to adulthood: a review’ that appeared in International Journal of Andrology (31: 1–11, 2008) with interest (Sijstermans et al., 2008). In the second paragraph of page 9, it was written that the cremasteric reflex peaks in boys 5–8 years old (Bingöl-Koloǧlu et al., 2001) and it is generally accepted that retractile testis may represent hyperactivity of the cremasteric reflex (Farrington, 1968; Tanyel, 2004). Since two articles of ours are cited (Bingöl-Koloǧlu et al., 2001; Tanyel, 2004), this sentence tells that we agree on the views about the effect of cremasteric reflex on the localization of a testis. However, it is clearly described in those mentioned articles that cremasteric reflex cannot explain the suprascrotal localization of a testis. Therefore those articles oppose to the idea of the place of the cremasteric reflex, which is very contrary to their use in the aforementioned article. Since my articles are not cited in their exact meaning, I think that the readers of your Journal should be informed about their exact views. In those articles, it is described that a reflex arc cannot be reactivated during the active state. The reflex arc can be reactivated after the completion of the precedingly activated arc. If a testis is retracted because of activities of this reflex, it should go up and down. However, such a testis does not exist. Furthermore, the cremasteric reflex is subjected to desensitization. It cannot be reactivated continuously. Therefore the cremasteric reflex cannot explain the suprascrotal localization of a testis (Bingöl-Koloǧlu et al., 2001). My description includes the development of smooth muscle in the gubernaculum to descend the testis. Testis is descended through the processus vaginalis via peristaltic activity. After descent, the smooth muscle should undergo programmed cell death for the obliteration of processus vaginalis. The initiation of programmed cell death requires a decrease in sympathetic, but an increase in parasympathetic tonus. Undescended testis results from early activation of this pathway that diminishes the amount of smooth muscle to descend the testis. Undescended testis is associated with a permanent decrease in sympathetic and increase in parasympathetic tonuses. Such an alteration in signalling increases cytosolic calcium in the cremaster muscle. Even if the amount of smooth muscle is initially enough for descent, the permanent increase in cytosolic calcium results in contraction, and furthermore contracture formation of the cremaster muscle. As it will be noticed in the cited articles, I think that not the cremasteric reflex, but the contractile status of cremaster muscle defines the retraction or ascent of a testis (Bingöl-Koloǧlu et al., 2001; Tanyel, 2004).