Cryptorchid Surgery
Cryptorchism is defined as the failure of one or both testicles to descend into the scrotum. The cryptorchid testicle can
be located anywhere along the path from the area of fetal development of the gonads (just caudal to the caudal pole of the
kidney) to the subcutaneous tissue between the external inguinal ring and the scrotum. Thus a cryptorchid testicle can be
located in the abdominal cavity, in the inguinal canal, or in the subcutaneous tissue between the external inguinal ring and
the scrotum.
Diagnosis
Testicles should be easily palpated in the scrotum of dogs and cats greater than 2 - 4 months of age. If one or both testicles
are not located in the scrotum careful palpation will reveal which testicle(s) are involved and whether the testicle(s) are
located in the subcutaneous tissue. Failure to palpate a testicle in the scrotum or the subcutaneous tissue leads to a presumptive
diagnosis of abdominal cryptorchidism. Palpation of the testicle in the subcutaneous tissue leads to a diagnosis of subcutaneous
cryptorchidism.
Surgical Technique
Subcutaneous cryptorcidism. If the cryptorchid testicle is palpated in the subcutaneous tissue, incision directly over the
testicle will allow exposure and removal of the testicle.
Abdominal cryptorcidism. Locating an abdominal testicle is generally very easy. The critical factor to remember is that both
ductus deferens enter the urethra at the prostate. If you trace the ductus deferens from the prostatic urethra cranially it
is located dorsal to the bladder until it passes the junction of the ureter and the bladder. Cranial to the point where the
respective ureter enters the bladder the ductus deferens turns laterally on its course to the testicle. This anatomical feature
makes it extremely easy to find an abdominal testicle.
In the dog the skin incision is made in the caudal abdominal skin just lateral to the prepuce on the side of the cryptorchid
testicle. Entry into the abdomen is on the midline through the linea alba by undermining under the prepuce to the midline.
Incising the linea alba allows exposure of the urinary bladder. Caudal reflection of the urinary bladder, exposing the dorsal
surface of the bladder, will allow visualization of both ductus deferens. Gentle retraction of the ductus of the cryptorchid
testicle will allow delivery of the testicle into the surgical site, ligation of the testicular vessels and excision of the
testicle.
In the cat the skin incision is made in the caudal abdominal skin on the midline. Entry into the abdomen is on the midline
through the linea alba and allows exposure of the urinary bladder. Caudal reflection of the urinary bladder, exposing the
dorsal surface of the bladder, will allow visualization of both ductus deferens. Gentle retraction of the ductus of the cryptorchid
testicle will allow delivery of the testicle into the surgical site, ligation of the testicular vessels and excision of the
testicle.
On occasion cryptorchid testicles are trapped between the muscles layers in the inguinal canal. When this occurs gentle tension
on the ductus deferens will allow visualization of the ductus deferens entering the inguinal canal. Gently teasing the musculature
of the internal inguinal ring apart with a blunt instrument is often enough to allow delivery of the testicle back into the
abdomen for removal.
Frequently cryptorchid testicles are smaller than normal and it is possible that the cryptorchid testicle will be in the subcutaneous
tissue but not be palpable. Entry into the abdomen, assuming abdominal cryptorchidism, would, therefore, fail to reveal the
cryptorchid testicle. Gentle tension on the ductus deferens would confirm that the ductus deferens passes through the inguinal
canal. The caudal abdominal skin incision is of value here, as from that incision you can undermine the skin between the incision
and the external inguinal ring. Gentle traction on the abdominal ductus will allow you to locate the ductus deferens as it
exits the inguinal canal and will lead you to the cryptorchid testicle.
Once the cryptorchid testicle is located, either in the abdomen or the subcutaneous tissue, it can be excised using any standard
technique. For very small testicles with small vessels and a small ductus deferens I will use the figure eight knot in the
spermatic cord. For larger testicles, with larger spermatic cords I will clamp the spermatic cord with hemostats, transect
distal to the most distal hemostat and place a ligature using Miller's knot in the area of the spermatic cord crushed by the
most proximal hemostat. In dogs weighing over 18 kg, I will clamp the spermatic cord with three hemostats, transect distal
to the most distal hemostat, place a ligature using Miller's knot in the area of the spermatic cord crushed by the most proximal
hemostat, and a transfixation ligature in the area of the spermatic cord crushed by the second hemostat.
