A comparative study of ovariectomy and ovariohysterectomy in the Bitch
Absztrakt
The object of this study was to research and analyse both methods of gonadectomy. By compiling
this research paper I gained an indepth understanding of both OHE and OVE. What I have
learned will be of great benefit to me for my future veterinary career. Gonadectomy forms an
essential part of the daily work carried by any small animal practice and there is a constant
ongoing debate as to whether OHE or OVE should be the preferred method.
There are many indications for gonadectomy. The first and most obvious of all is for the
prevention of unwanted pregnancies. The modern world is continuously becoming more
populated by dogs and there is a greater need than ever to control the birth rates. Gonadectomy is
the ultimate choice as it is a once off procedure that is effective for life. OHE can be used to treat
pyometra and has excellent success rates when compared to the conservative methods of
treatment, and both OVE and OHE can be used for the prevention of pyometra as it is a hormone
dependent disease. Both forms of gonadectomy are useful in the control of diabetes mellitus. In a
bitch the earlier you neuter before the third heat the less chance there is of developing mammary
gland tumours. Gonadectomy is also useful in the termination of an unwanted pregnancy when
no further breeding is required of the bitch. In general the same indications exist for OVE and
OHE. In most situations OVE is sufficient with the exception of cases where there is disease of
the uterus.
When thinking about performing gonadectomy, it is very important to decide upon the correct
time for doing so. For this an understanding of the oestrous cycle is required. When the
progesterone level is low, which is during anoestrus, is the ideal time to spay. This prevents the
creation of an iatrogenic pseudopregnancy. Also it is best to avoid surgical operations on the
reproductive tract during oestrus as there is an increased vascularity of the tissue and vessels and
the likelihood of uncontrollable bleeding is greater. When discussing the correct age at which a
bitch should be spayed it is important to take note of prepubertal gonadectomy. The procedure of
neutering sexually immature puppies is frequently carried out, especially in the United States of
America. There have been arguments both for and against this practice and it is predominately
used in animal shelters as a drastic method to control the pet population.
In relation to the surgical procedure itself, the only difference that exists in technique is that in
OVE the uterus remains in the body. Other than this the techniques are quite similar and straight forward. They both involve entry by laparotomy, ligation and transection of the ovarian pedicles.
OVE requires ligation and transection between the tip of the uterus and the ovaries, while OHE
requires the careful ligation, transection and removal of the uterus. This is done at the level of the
cervix.
With this 'routine' operation however there can be complications of course. These are most often
experienced in large, deep chested and overweight bitches. Like all surgeries both OHE and OVE
carry a standard set of surgical complication but these appear to be of more note in OHE,
especially the occurrence of undesired intraoperative and postoperative haemorrhage. Other than
this both operations carry the same hormone dependent consequences, which cannot be
eliminated by choosing one surgery technique over the other. Stump granuloma can only occur in
OHE and accidental ligation of the ureter can happen in both surgeries both is more common in
OHE when ligation around the cervix is possible.
When the advantages and disadvantages of both procedures are compared and weighted up
against each other it is very clear that the differences are minimal. It is very possibly that the lack
of drastic differences is why some small animal surgeons are so reluctant to change their ways
and adopt OVE as the choice surgery. It is believable that if huge advantages of OVE were
demonstrated, veterinarians would be more likely to quickly chose this as their method for
performing elective gonadectomy. Despite the lack of dramatic results, the situation remains
simple and clear. OVE is as good as OHE with almost identical indications and complications.
There are no benefits to be gained from removing the uterus therefore OVE should be every
veterinarian’s first choice when performing elective gonadectomy.