Author

Stephen J. Birchard DVM, MS, Diplomate ACVS

Tuesday, July 29, 2014

Cryptorchidism in Dogs: 5 ways to make surgery easier

1. Determine which testicle is retained
Perform a thorough physical examination.(1) Carefully evaluate the scrotum, prescrotal area, inguinal canals, and abdominal cavity. If only 1 testicle is present in the scrotum, push it dorsally and cranially into the inguinal canal to determine whether it is the right or left testicle. After determining which testicle is retained, carefully palpate the prescrotal area and inguinal canal on the affected side. Palpation of the testicle in the inguinal region may be difficult since it can be confused with inguinal fat or lymph node. Ultrasound examination may be helpful to identify the testicle since it has a characteristic appearance (See recent paper on ultrasonography for retained testicles by Felumlee, Reichle, Hecht, et.al. http://onlinelibrary.wiley.com/.../j.1740-8261.../abstract)
Fig. 1: Ultrasound of a cryptorchid dog with a retained testicle found in the abdomen (arrow)
Also perform abdominal palpation, but unless the retained testicle is severely enlarged it will be difficult to palpate.

2. Begin with an incision over the pre-scrotal or inguinal region
Testicles located just cranial to the scrotum can be removed either by pushing the testicle caudally and exposing it through a standard pre-scrotal midline incision, or by simply incising directly over the testicle. Retained testicles in the inguinal area require incision directly over the inguinal canal. (Fig. 2a)
Fig. 2a: Inguinal incision for removal of right sided retained testicle
(Figs 2a through 2f are from: Birchard SJ, Nappier M. Cryptorchidism.
Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.)
Meticulous and thorough dissection may be required to expose the testicle. Be careful not to injure the pudendoepigastric artery and vein and its branches. It is possible to confuse the inguinal lymph node with the testicle. However, careful dissection and gross examination of the structure should allow differentiation before proceeding with the excision. Once the testicle and associated structures are exposed, remove them as described for prescrotal or normal testicles.

3. For an abdominal testicle, perform a paramedian approach
If one testicle is retained in the abdominal cavity, the paramedian approach to the abdomen offers the advantages of avoiding dissection around the prepuce, which necessitates ligation of the caudal superficial epigastric artery and vein, and not creating dead space in the subcutaneous tissues adjacent to the prepuce. Although the paramedian approach can allow removal of the testicle through a smaller incision than the ventral midline approach, the surgeon should not compromise the exposure of the intra-abdominal structures. Carefully identify the caudal abdominal structures, and expose and remove the testicle only after verifying that the correct structures have been identified. In one clinical study, the prostate gland was inadvertently removed in 3 dogs when insufficient exposure had been obtained while attempting to remove an abdominal testicle.(2) If additional exposure is needed to identify key structures, enlarge the abdominal incision and use appropriate retractors to find the testicle and surrounding organs.

For the paramedian caudal abdominal approach, place the dog in dorsal recumbency, and prepare the ventral abdomen for aseptic surgery. Depending upon the size of dog, make a 6-10 cm incision in the ventral abdomen, approximately 3-4cm lateral to the prepuce. (Fig. 2a)  Incise the subcutaneous tissue to expose the fascia of the rectus abdominus muscle using a scalpel, make a nick incision in the fascia, and sharply incise the fascia with Mayo scissors (not the muscle). (Fig. 2b) 
Fig. 2b: Sharply incise the rectus abdominus fascia with Mayo scissors
Bluntly separate the fibers of the rectus abdominus muscle, beginning with Mayo scissors, then continuing with the index finger of both hands. (Fig. 2c) 
Fig. 2c: Bluntly separate the muscle fibers of the rectus abdominus with fingers
Sharply incise the peritoneum. (Fig. 2d) 
Fig. 2d: Sharply incise the peritoneum with scissors
Place moistened laparotomy sponges on both sides of the body wall, and place a Balfour retractor or hand held retractors to retract the abdominal wall and expose the viscera.

4. Exteriorize the urinary bladder and palpate the prostate gland
If the retained testicle is not immediately seen in the abdominal cavity after making the paramedian approach, exteriorize the urinary bladder and retract it caudally. Identify the prostate gland, and the vas deferens entering the prostate.
Fig. 2e: Exteriorize the urinary bladder and identify the prostate gland and vas deferens
5. Find the vas deferens and follow it to the testicle
Follow the vas deferens cranially until the testicle is located. (Fig. 2e) Triple ligate the vas deferens and the vessels with absorbable suture, cut between the distal 2 ligatures, and remove the testicle.

Rarely, the abdominal approach and identification of the vas deferens may reveal that the testicle is in the inguinal canal. Remove the testicle as previously described in the inguinal approach.

Close the abdominal incision by first closing the external rectus fascia with absorbable suture (e.g. polydioxanone) in either a simple interrupted or simple continuous pattern.(Fig. 2f) Close the subcutaneous tissue and skin routinely.
Fig. 2f: Close the external rectus fascia, subcutaneous tissue, and skin routinely
Fig. 3: Testicular torsion of an abdominal testicle in a 5 month old Boxer
(same dog as in Figure 1) removed by the paramedian approach. 
References

1. Birchard SJ, Nappier M. Cryptorchidism. Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.
2. Schulz KS, Waldron DR, Smith MM, et al: Inadvertent prostatectomy as a complication of cryptorchidectomy in four dogs. J Am An Hosp Assoc 32: 211-214, 1996.