The physiology of ejaculation – Breaking the dogma

S. Alloussi (1); R. Eichel(2); Ch. Lang (3); S.H. Alloussi (4)

(1) Dept. of Urology, Diakonie Klinikum Neunkirchen; Academic teaching hospital of Saar University, Germany
(2) Urologist, Out Patient Clinic, Neunkirchen
(3) Dept. of Urology, Knappschaftskrankenhaus Sulzbach Academic teaching hospital of Saar University, Germany
(4) Dept. of Urology, University of Bale, Switzerland

The theory of ejaculation was established in the 70s by Marberger. In particular the internal spincter which represent the theoretical cornerstone of the ejaculation process. However, new aspects have been found questioning this doctrine resulting in new knowledge about the process as well as in new ejaculation preserving operation techniques. However the exact physiology of the ejaculation is still unknown. Current studies are regarding the internal spincter as benchmark for keeping the antegradic ejaculation which should be critically reviewed.

Materials and Methods:
Urologic literature and relevant studies were reviewed for new aspect in the physiology of ejaculation. With studies regarding different examination techniques such as videourodynamic, ultrasound, sperm analyses and new histological data as well as new surgical procedures the assignment of the internal spincter for the ejaculation process has been critically reviewed and challenged. An alternative theory with respect to these new findings has been developed.

Clinical Observation: Sonographical studies of Gil-Vernet et al. and Hermabessiere et al. as well as videourodynamical observation proved that there is no pressurized chamber built during the process of ejaculation. The internal spincter has no function in the process.
Microscopical findings of ejaculate: Ndove et al. showed that different parts of the ejaculate appear on different timepoints. This fractionated release of compounds of the sperm is against the common theory of building up a pressurized chamber which would need an internal spincter.
Histoanatomy: Dorschner et al. found a new muscle in the crista muscularis. This musculus ejaculatorius adapts as histological structure which moves the verumontanum distally. With respect to the physiological aspects this muscle shows a high concentration of alpha-adrenergic receptors.
Missing ejaculation after the intake of alpha-blocker is related to an insufficient or missing ability for contraction of the m. ejaculatorius. This alpha-adrenergic innervation can be antagonized by imipramine.
Ejaculation-preserving TUR-Prostate: By saving these important structures a new resection technique with persisting antegradic ejaculation in >90% of patients receiving TUR-prostate underlining these aspects.

Based on these results it could be proved that the current theory about the process of ejaculation published by Marberger is wrong. With respect to the new aspects found in the literature, a new model regarding the process of ejaculation is necessary and was established. This new aspects proved that the internal sphincter is not necessary and should not be seen as benchmark for antegradic ejaculation in future studies.