2.8 Diagnosis and Castration of Cryptorchids

What is cryptorchidism?

What is cryptorchidism?

Failure of both or one of the testes to descend into the scrotum. Can be unilateral (usually left) or bilateral.

When is a stallion classed as cryptorchid?

2 years old.

What are the types of cryptorchidism?

• Complete abdominal cryptorchidism: Both the epididymis and the testis are located within the abdomen.

• Incomplete abdominal cryptorchidism: The epididymis, but not the testis, has descended into the inguinal canal.

• Inguinal cryptorchidism: The epididymis and testis have descended into the inguinal canal, but not into the scrotum – called “high-flankers”.

What are the causes of cryptorchidism?

• Heritable – genetics, improper gubernaculum function, too large testis to pass through inguinal canal.

• Hormonal: inadequate stimulation of androgen or testosterone.

When is a cryptorchid stallion still fertile?

Unilateral cryptorchidism.

How is cryptorchidism diagnosed?

• History – has the horse been castrated previously?

• External palpation: give sedatives to relax the m. cremaster – can always palpate it in case of inguinal cryptorchidism and physiological descension. If m.cremaster can be palpated, testicle is not an abdominal cryptorchid.

• Rectal palpation of inguinal rings: If there are no structures in the inguinal region, then cryptorchidism is completely in the abdominal cavity. If there are vessels in the inguinal region, cryptorchidism is inguinal or incompletely in the abdominal cavity.

• USG – typical homogenic echogenic appearance.

• Hormonal assays: Testosterone concentration. Blood: anti-Mullerian hormone increased (from Sertoli cells in cryptorchid testes), testosterone decreased. Urine: oestrogen

• Exploratory laparoscopy

How is cryptorchidism treated?

Surgical removal of both testes under general anaesthesia. Always locate and remove the cryptorchid testicle first.

How can a stallion be castrated without surgery?

Immunological castration = Immunisation against luteinizing hormone-releasing hormone (LHRH), to decrease serum concentration of testosterone. This has a variable result.

What are the different surgical methods for cryptorchidism?

• Inguinal

• Para-inguinal

• Paramedian

• Flank

• Laparoscopic

What type of cryptorchidism is the inguinal approach used for?

Inguinal and incomplete abdominal

How is the inguinal removal of cryptorchid testes carried out?

• Dorsal recumbency

• Incise over the superficial inguinal canal, cut rectus abdominis, locate the vaginal process from the gubernaculum

• Incise vaginal process to locate testicle and epididymis. find the proper ligament of testis, so the testis can be pulled through the vaginal ring.

• Suture with absorbable suture the superficial inguinal ring to prevent evisceration.

When is the para-inguinal approach used?

If the inguinal method didn’t work.

How is the para-inguinal approach carried out?

An incision is made several cm medial to the inguinal ring; cranially to the external inguinal canal. Incision between raphe scroti and left leg. Cut rectus abdominis, aponeurosis of external abdominal oblique muscle.

When is the paramedian approach used?

Abdominal cryptorchidism.

How is the paramedian approach carried out?

• Open abdomen as medial as possible

• Open skin, subcutis and the locate external facia flava abdominis – under this is aponeurosis of oblique abdominal muscle – cut through this

• Find fibres of rectus abdominis and separate them with finger - under here is the transverse fascia with peritoneum which is perforated – then introduce hand into abdomen and remove testicle

• Do ligature, reposition of stump of spermatic cord and put suture on fascia transversalis (which is the main structure holding the abdominal wall).

When is the flank approach used?

Abdominal cryptorchidism. Invasive so not common.

How is the flank approach carried out?

• 10-15 cm incision is made through skin and subcutis in the paralumbar fossa of the affected side with the horse standing/recumbent.

• The external abdominal oblique muscles must be cut, and the peritoneum is exposed by splitting the internal abdominal oblique and transversus abdominis muscles.

• Peritoneum cut and testes located and removed.

What are the benefits and consequences of the laparoscopic method?

Minimally invasive, but requires expensive equipment. Done standing or recumbent.

How can the horse be positioned for recumbent laparoscopic cryptorchid castration?

Drop head/elevate legs to remove pressure of GIT on inguinal region (increases pressure on lungs)

How is the laparoscopic method carried out?

Distend abdomen with gas, insert camera through umbilical region. Locate testicle(s) around the vaginal ring and remove.

What is the post-operative care for cryptorchidism surgery?

• Stall rest, lead walking only.

• Antibiotics: potentiated sulfonamides or procaine penicillin for 7 days

• NSAIDs: 5-7 days

• Exercise gradually resumed in the next 10-14 days. External sutures may be removed 7 days post-op.

• Laparoscopically less invasive = resume activity after the first 72 hours.

What are the potential complications of cryptorchidism surgery?

Rare. Anaesthetic complications, excessive haemorrhage, evisceration, bowel damage, infection, post-op swelling, incision breakdown and continued stallion behaviour.

Which muscles are cut through on the paramedian approach for cryptorchidism surgery?

m. rectus abdominis.

How can a castrated horse be differentiated from an abdominal cryptorchid?

• Cannot palpate internal inguinal ring.

• Hormonal assays. Blood: anti-muellerian hormone, testosterone; Urine: oestrogen.

How does a testicle look on USG?

Hyperechoic.

Which method is used for castration of complete cryptorchidism, and which muscles are cut?

Paramedian, m. rectus abdominis.

What is given to make rectal palpation more comfortable?

Buscopan.

Which cells make testosterone and what causes the release?

GnRH → LH from the pituitary gland stimulates Leydig cells to release it.