Ejaculatory dysfunctions (ED) are an important cause of postoperative dissatisfaction, which lead to a decrease in the intensity of orgasms in 50% of patients. ED is a cause for concern for almost a third of patients who need surgery. Surgical techniques have been developed to limit the occurrence of postoperative ED, but their results remain heterogeneous.

There are very few studies on the biomechanical anatomy of ejaculation. Ejaculation is a complex phenomenon involving different structures and in particular the Veru Montanum. This is the key element in the emission of ejaculate within the prostatic urethra. In addition, there is a structure located in the resection zone of the prostate adenoma. It has therefore been suggested that its resection was a primary source of ED.

A single observational study carried out in by Gil Vernet et al in 1994 evaluated on a single healthy 18-year-old volunteer the ejaculatory mechanism of expulsion using an endorectal probe recording the movements of the prostate, the bladder neck and of the proximal urethra during ejaculation.

A contemporary study of the biomechanics of the ejaculatory expulsion phase could confirm and improve understanding of the involvement of anatomical structures. The results of our study aim to adapt surgical techniques aimed at limiting the risk of postoperative ED.

Inclusion Criteria:

• Affiliated subject or beneficiary of a social security scheme
• Subject agreeing to participate and having signed the free, informed consent.

Exclusion Criteria:

• Subject with ejaculatory dysfunction
• Subject with urinary dysfunction
• History of urinary or penile surgery
• Subject with untreated urinary tract infection
• History of chronic prostatitis
• Pathology making it impossible to introduce the endorectal probe or the ureteroscope
• History of colorectal inflammatory disease
• Recent intake (within 30 days) of drugs known to interfere with ejaculation
• History of intolerance or allergy to any of the drugs used in the study
• Subject participating in another clinical study
• Adults under guardianship, curatorship or other legal protection; deprived of liberty by judicial or administrative decision; Hospitalized without consent.