Clinical findings in 10 horses diagnosed with monorchidism following exploratory laparotomy or standing laparoscopic surgery

Is anti-müllerian hormone useful for monorchidism diagnosis in the tomcat?

Monorchidism is an uncommon condition in tomcats, defined by the congenital absence of one of the testicles. Due to the lack of information regarding possible biomarkers, most monorchidism cases require laparotomy in order to differentiate it from cryptorchidism. Human data suggest that monorchid patients have lower serum anti-Müllerian hormone (AMH) levels when compared to cryptorchids, premises that has been also scrutinized in veterinary medicine. Here, we describe a case of monorchidism in a tomcat, focusing on the clinical findings and the dynamics of AMH serum levels before and after the removal of the singularly identified testicle. To contribute to the limited knowledge of AMH levels across different reproductive statuses in tomcats, the findings from this monorchid case were compared to values obtained from two cryptorchid tomcats (one unilateral and one bilateral), three intact tomcats, and three castrated tomcats. In addition, clinical, histopathological and ultrasound examinations were conducted in all tomcats. The AMH levels in the monorchid tomcat revealed a consistent decrease after surgery, from 27.3 ± 0.2 ng/ml when the testicle was still present, to 2.3 ± 0.2 ng/ml 1 week later, and further decreasing below the detection limit (<0.15 ng/ml) for the last 2 weeks of the trial, matching the AMH level of the castrated male. AMH serum levels of the bilateral and unilateral cryptorchid tomcat (22.5 ± 0.3 ng/ml; 24.1 ± 0.2 ng/ml) were in agreement with those of the three intact males (19.1 ± 2.2 ng/ml) and the monorchid prior to surgery. AMH testing effectively confirmed the absence of testicular tissue after unilateral orchiectomy in a monorchid tomcat but did not differentiate between monorchidism and cryptorchidism. To our knowledge, this is the first case of monorchidism in tomcats, in which AMH levels before and after surgery have been determined.

Diagnostic Approach to Equine Testicular Disorders

Management of breeding stallions is crucial to equine reproduction. The longevity of the breeding career is the ultimate objective, whether the stallion is used for natural cover or for semen collection and artificial insemination. Stud farm veterinarians should be aware of the techniques used to evaluate testicular function and the diagnostic approach to testicular disorders in cases of emergency. This paper presents the clinical methods used to evaluate testicular health, including palpation, ultrasonography, biopsy, and fine-needle aspiration. The discussion of testicular disorders is broken down into four categories: congenital disorders (cryptorchidism, monorchidism, and testicular hypoplasia), differential diagnosis of scrotal enlargement, differential diagnosis of causes of progressive testicular enlargement, and differential diagnosis of testicular asymmetry or reduction in size with an emphasis on testicular degeneration. The sudden increase in testicular size is often accompanied by severe clinical signs and is a major cause for referral of stallion for surgery. Testicular disorders are illustrated with clinical cases seen by the authors.

A Single-Port, Multiple-Access, Custom-Made Device Used in Laparoscopically Assisted Cryptorchidectomy in Standing Horses-A Preliminary Study

This study evaluates a new multiport device with single access to the abdominal cavity produced with routine hospital supplies that could be applied to laparoscopically assisted cryptorchidectomy in standing horses. Initially, the new device was evaluated on five cadavers of bovine fetuses (n = 5), placed assisted in a minilaparotomy performed in the flank region. Subsequently, the device was evaluated in four cryptorchid horses treated during the hospital routine. During the evaluation of the new device, the possibilities of exploring the abdominal cavity, inspection, and intra-abdominal manipulation with two Babcock forceps were verified. The possibilities were described, and surgical time data were recorded and analyzed using descriptive statistics. In the cadavers, a wide exploration of the abdominal cavity was possible, with a laparoscopic inspection through the right paralumbar fossa and manipulation of intra-abdominal structures with Babcock forceps inserted by the new device. In cryptorchid horses, laparoscopically assisted cryptorchidectomy with a new device was feasible in two patients, and in the others, it allowed the diagnosis of adhesions and ectopic locations in the inguinal region of testicles retained in the cavity. Therefore, the new device was efficient in exploring the inguinal region of cryptorchid horses in the standing position. The present study is preliminary and can support future studies that aim to improve the developed prototype.

Monorchidism in a Phenotypic Mare With a 64,XY, SRY-Positive Karyotype

Disorders of sexual development (DSD) are associated with atypical chromosomal, gonadal, or phenotypic sex. It is likely that the number of cases of DSD are underestimated in the equine population. Monorchidism in the horse is very rare. This case report describes the clinical assessment of a phenotypic mare with stallion-like behavior which led to the diagnosis of a DSD. A 4-year-old Quarter Horse mare presented in good body condition, with normal external genitalia for a mare, and normal mammary glands with two bilaterally symmetric teats. No uterus, cervix, or gonads were detected on transrectal palpation. Transrectal ultrasonography revealed a single gonad in the right dorsal abdomen with the morphologic appearance of a testicle. Presurgical hormonal evaluation revealed elevated serum testosterone and anti-Müllerian hormone (AMH) concentrations. The right gonad was successfully removed via standing exploratory laparoscopy and submitted for histopathology. No gonad was identified on the left side during laparoscopy. Histopathologic examination confirmed that the excised gonad was a testicle. Cytogenetic and molecular analysis revealed a 64,XY, SRY-positive chromosomal constitution. Hormonal evaluation 5 weeks after surgery revealed low serum testosterone and AMH levels. A diagnosis of monorchidism was based on ultrasound examination, laparoscopic exploration of the abdomen, removal of a single gonad, and a subsequent decrease in serum testosterone and AMH concentrations to basal levels. In summary, a combination of clinical signs, endocrine evaluation, chromosomal and molecular analysis, and histopathology can be used in the diagnosis of DSD conditions.

Current Use of Equine Laparoscopy in Urogenital Disorders: A Scoping Review of the Literature from 2000 to 2021

(1) Background: Laparoscopic surgery replaced traditional invasive techniques for the treatment of common urogenital disorders in equids. The aim of this review is to evaluate applications and the development of urogenital laparoscopy from 2001 to 2021. (2) Methods: A scoping review of literature was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for scoping reviews on three databases (NCBI-PubMed, Web of Science-Thompson Reuters, and SciVerse Scopus). (3) Results: A total of 452 papers were identified. After duplicate removal and title screening, 181 papers underwent abstract screening. Of these, 160 + 10 papers (cited by others) were assessed for eligibility according to the PICOs. A total of 132 papers were considered eligible. Most of the research was focused on ovaries and testes, followed by urinary bladder and general articles about laparoscopy in horses. We identified 43 original studies (33%, RCT, NoRCT, and experimental trials), 39 case series/retrospective studies (29%), 37 case reports (28%), and 13 reviews (10%, narrative or systematic). (4) Conclusions: Gonadal disorders were the most investigated. Hand-Assisted Laparoscopic Surgery (HALS) and laparoscopic-assisted surgery represent valuable options for more challenging conditions (uterine and urinary bladder disorders).

Animal Model of Video-Assisted Cecum and Ileum Instrumentation for Equine Visceral Pain Study

This study aimed to describe an animal model for studying equine visceral pain using minimally invasive and video-assisted cecum and ileum instrumentation. The access to the cecum and ileum was affected because of a previous typhlostomy. For video-assisted distention of the cecum and ileum, a distention device, which we developed using an endotracheal Rusch probe, was used, adapted, and coupled to a cuffometer to inflate and measure the pressure of the cuff attached to its distal portion. In a video-assisted manner, the distal portion of the device was introduced into the cecum and ileum, which contained the cuff in its distal portion, properly positioning it in the lumen. The cuff of the distension device was insufflated after the measurement of baseline physiological parameters of the animals and video-assisted confirmation of its right placement in the cecum and ileum lumen (M0). Was performed in one moment through two simultaneous cuff compressions and 1 minute of animal observation to evaluate the degree of abdominal discomfort manifestations (M1). To cease these stimuli, the cuff was deflated by disconnecting the extensor of the distension device attached to its proximal portion (M2). The procedure was easily performed in most cases. Slow and progressive insufflation allowed subjective adjustment of the intensity of the pain stimulus based on behavioral manifestations. Even with a low rate of complications, the model is feasible and reproducible for studies on visceral pain and the evaluation of analgesic effects.