The complex blood supply to the equine testis as a cause of failure in laparoscopic castration.

The research investigates the failure of laparoscopic castration procedure in horses, suggesting the complex blood supply to the equine testis as a potential cause. It argues that an alternate blood supply may lead to incomplete testis necrosis after the transection of the spermatic cord, resulting in castration failures in both normal and cryptorchid stallions.

Research Objectives and Methods

• The primary aim of this study was to understand whether an alternate blood supply could inhibit total testis necrosis post-spermatic cord transection. Additionally, the researchers sought to determine the frequency of this concern in both normal and cryptorchid stallions.
• To investigate this, they first conducted a preliminary study on eight normal stallions in which they ligated and transected the spermatic cords at different sites and in different manners. After five weeks, they evaluated the vitality of both the testes and epididymes after removal.
• Next, a prospective clinical trial was performed, where intra-abdominal spermatic cord transection was conducted on 241 stallions, including both cryptorchid and normal individuals. In situations of surgical failure, the testes were removed for histological analysis.

Research Results

• Post-examination, it was detected that all epididymes were either entirely or largely unscathed in the preliminary study animals. Except for one, all testes were completely necrotic.
• In the horses that underwent surgery, all abdominally retained testes were necrotic, and only a small percentage of inguinally retained and normally descended testes had partially survived. It was observed that the pattern of survival varied between the latter two categories. It was attributed to an alternate blood supply provided by the anastomosing vessels from the cremasteric artery.
• This research concluded that 5.6% of the inguinally retained and 3.4% of the normally descended testes in the sample did not fully necrotize after intra-abdominal transection due to an alternate blood supply via either the cremasteric or external pudendal artery. The study also pointed out that in the case of normally descended testes, a tributary from the external pudendal artery often led to their partial survival.

Conclusions and Implications

• The research concluded that the alternate blood supply led to castration failures due to incomplete necrosis in a small percentage of inguinal cryptorchids and normal stallions. Despite this being a minimal percentage, the study suggests that laparoscopic castration without orchidectomy cannot be considered a reliable method for these categories of stallions.
• The implications and key findings from this research are beneficial for veterinary surgeons, as it informs what anomalies could occur during the laparoscopic castration process, allowing them to anticipate and mitigate these complications.