Use of transabdominal ultrasonography to determine the location of cryptorchid testes in the horse.
Authors: Schambourg M A, Farley J A, Marcoux M, Laverty S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Transabdominal Ultrasonography for Cryptorchid Testis Localisation Cryptorchidism presents a diagnostic challenge in equine practice, particularly when testes are intra-abdominal; whilst transrectal ultrasonography is established as reliable, it carries risks and practical limitations in young, fractious or small horses. Schambourg and colleagues evaluated transabdominal ultrasonography as an alternative imaging modality by scanning 38 horses with confirmed cryptorchidism across a weight range of 175–760 kg, with surgical or necropsy findings used as the gold standard for validation. The technique achieved 97.6% sensitivity (93.2% when including two cases obscured by heavy winter coats) and 100% specificity, successfully localising 22 intra-abdominal, 19 inguinal and 3 subcutaneous testes. The transabdominal approach offers immediate diagnostic certainty regardless of age, temperament or body size, and crucially allows practitioners to determine testis location—whether abdominal, inguinal or subcutaneous—before selecting the most appropriate surgical removal technique. For farriers and vets managing cryptorchid cases, this validates transabdominal ultrasonography as a safe, non-invasive first-line imaging tool that can be performed on standing horses without the risks associated with rectal manipulation, though coat quality should be optimised for adequate probe contact.
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Practical Takeaways
- •Transabdominal ultrasonography is a safe, non-hazardous alternative to transrectal ultrasound for localizing cryptorchid testes, particularly useful for fractious, young, or small horses
- •The technique provides immediate, precise anatomical localization to guide surgical approach selection, improving surgical planning and efficiency
- •Ensure adequate clipping or grooming of the surgical site before imaging, as heavy hair coats can compromise image quality and lead to missed lesions
Key Findings
- •Transabdominal ultrasonography achieved 97.6% sensitivity and 100% specificity for locating cryptorchid testes (excluding cases with excessive hair coat)
- •22 of 38 testes were located within the abdomen, 19 in the inguinal space, and 3 in subcutaneous locations
- •Technique was effective across all horse sizes (175-760 kg) and temperaments, including fractious and juvenile animals
- •Thick winter coat in 2 horses prevented adequate probe contact and visualization, highlighting a practical limitation