Intubation and monitoring of breathing with Breathe Safe Respiratory Monitor (image 2).
Image 2 – Breathe Safe Respiratory Monitor
Instruments that are used for the procedure
Standard set for sterilization: surgical gloves, surgical sterile sheet, surgical tweezers – Adison tissue, scalpel – No. 10, needle holder – Mayo Hager, hook (spay hook) for ovariohysterectomy, four surgical forceps – Mosquito forceps, surgical scissors – mayo scissor curved, four Backhaus towel clamps, surgical knife – No. 10, monofilament (Monosyn 3-0) resorptive threat, sterile gauze (image 3).
Image 3 – Ovariohysterectomy kit
Position of the patient
By using the lateral “flank” access the patient could be positioned in right or left dorsal recumbence depending of the surgeons opinion. The access at the right side is preferred by some surgeons because it provides better access to more cranially anatomically placed ovary and because the omentum covers the viscera when it’s used a left sided access (Dorn &Swist, 1977). From our experience there aren’t any advantages whether a left or right sided access is used, but the left side is better because the dominant hand is used for easy manipulation with the suspensory ligament. The animal is placed in lateral position by fixing the limbs in their extension (Krzaczynski, 1974) – image 4.
Image 4 – Lateral position with limbs fixed in extension
The surgical field is being shaved by starting cranially from the last rib all the way down to the iliac bone in cranial-caudal direction and the transversal processes of the lumbar vertebrae, all the way down to the mammary complex in dorsal-ventral projection.
Marking the incision
The carving of the incision may be placed in dorsal-ventral or cranial-caudal direction, however by our experience we use the technique of cranial-caudal incision by which the incision is placed in one conceived central line, two fingers from the last rib, one finger from the transversal processes and two fingers from the iliac bone in diameter of 1-1,5 cm (image 5) depending on the size of the cat, estrus phase, or the presence of other possible complication factors.
Image 5 – Ready surgical field and appropriate location of incision for a left lateral access (left dashed line: location of the last rib; right dashed line: location of the iliac crest
The incision of the skin for the lateral “Flank” access can made in cranial caudal direction paying attention for avoiding the superficial blood vessels. The subdermal tissue must be cut with separating scissors (image 6). The abdominal muscles should be separated from the subdermal tissue and by using a forceps or scissors an incision must be made separately on every layer of the lateral abdominal muscles. When the abdomen is opened its important to fixate the abdominal muscle with a forceps, or the thumb, to maintain the control over the abdominal wall. The ovary or the uterine horn should be placed right under the incision.
Image 6 – Subcutaneous separation
The horn is pulled out by using (image 7 top).
Image 7 – Spay hook (top) and extraction of the horn of the uterus (bottom)
After the extraction of the horn and sighting the ovary, with the help of a forceps the ovary is fixated with the suspensory ligament (image 7 bottom). At older and obese cats the ovary is surrounded by adipose tissue, which requires prolonging the incision of the abdominal wall to achieve better visibility of the surgical field. After fixating the ovary/ligament the blood vessel is being ligated by placing two ligatures also used at the medial ventral access. The wide ligament (including the surrounding ligament) should be blindly separated parallel to the uterine artery at the level of the bifurcation of the uterus. After that, the uterine horn should be lifted to reveal the bifurcation and the contra lateral horn of the uterus, after which by using the hook the horn is lifted to a level of visibility of the contra lateral ovary, which is fixated with a forceps to the suspensory ligament. Because this ligament is on the opposite side it is harder to pull it out, and because it is shorter, it should be torn bluntly or be cut by scissors, and the rest of the procedure is the same as the other ovary. Then the both horns are pulled out until the bifurcation is visible. The both horns are being ligated twice near the bifurcation and are cut off 0,5 cm over the second ligature.
The visualization of the contra lateral ovary and horn of the uterus could be difficult to acquire through the small incision, but because the ipsilateral ovary is spotted right beneath the incision, by pulling out the horn all the way to the bifurcation, the contra lateral horn is pulled out by a hook, so is the contra lateral ovary. For easy visualization of the contra lateral ovary, the duodenum (left lateral “Flank” access) or the descendent colon (right lateral “Flank” access) are used to push dorsally the small intestine with the spay hook, simultaneously we pull the abdominal wall ventrally, and by doing so the visibility of the contra lateral ovary is bigger (image 8).
Image 8 – Extraction of the ovaries
To visualize the bifurcation of the uterus, by using the spay hook the small intestine and the bladder should be pulled in cranial and ventral direction simultaneously pulling the abdominal wall caudally, by doing so the uterine body lies dorsally of the bladders neck (image 9).
The abdominal wall at cats is closed by using a continuous suture, embracing the three layers of abdominal muscles. The skin is closed with a routine intra dermal suture, and by doing so, the extraction of the suture threads postoperatively is unnecessary (image 10).
Image 10 – Closing the skin wound by placing an intradermal suture
Postoperative care and analgesia
The postoperative care by using the lateral “Flank” access is nothing special, nor is necessary stationary observing postoperatively, so the patient could be checked out the very same day. The observation is done from distance and there is no need of bringing the patient back for a control. We used a single dose of NSAIL analgesic – meloxicam 0,2 mg/kg i/v.
RESULTS AND DISCUSION
In this study for ovariohysterectomy were involved 500 adult female cats at the age of 6 months to 9 years, with bodyweight of 2,5-5 kg. (Domestic and feral) which were electively brought to the clinic, which covers all the world known high standards of working in veterinary medicine.
The owners and volunteers in charge were informed of the whole process both verbally and in writing detailed description of the procedures and in this publication, their personal data isn’t mentioned and they remained completely anonymous.
The choice of anesthetic protocol and the analgesia in the postoperative period, depends on the procedure and the health status of the patient, including both acute and chronic diseases.
Even though there is no standard surgical access to ovariohysterectomy at cats, generally the ventral medial access dominates, in contrast to the lateral “Flank” access, which technique is less preferred (Bartels, 1998; Slatter, 2003).
The complexity to identify the subcutaneous adipose tissue and the internal and external oblique muscle and the peritoneum, during this access did not showed as a problem, so did the identification of the anatomical position of the ovaries and the uterus.
The risk of remaining ovarian tissue is rather often complication during ovariohysterectomy at cats, so is loosening of the ovarian ligatures during operation, which however doesn’t result with significant loss of blood (James at all, 2021). These intra operational complications didn’t showed as a problem with the application of the “Flank” lateral access in this study, considering the high level of competence and experience of the main surgeon, as is the use of modern materials for ligation and the use of modern surgical techniques as for ligating the ovaries and the
uterus and as for the fascia of mm. rectus abdominis.
By choosing the lateral “Flank” access to ovariohysterectomy at cats, there is lower degree of licking the wound, swelling and lower incidence of complications: bleeding of wound 0,5%, dehiscence of the wound 2%, infections of the wound 2,5% in the postoperative period (image 11).
Even though there is no general opinion for which procedure is better and it’s not used as a routine procedure, the lateral “Flank” access to ovariohysterectomy at cats in this study provede positive effect in veterinary surgeons during the intra and postoperative process, lower costs of material, so is the greater satisfaction of the owners and the comfort of the patients in the healing period.
Also the tress hold of pain during the lateral “Flank” access is very low, examined by Feline grimace scale fact sheet (Evanelista at all, 2019) by which a single dose of NSAID – meloxicam 0,2 mg/kg i/v is enough.
The lateral access in this study showed as better by the personnel that took place in the operations and the owners/fosters of patients because of the shorter operation time (
generally the difference is 10-15 minutes quicker), smaller surgical incision (1-1,5 cm), eased anatomical locating of the ovaries and uterus, quicker healing of the wound (2-4 days), smaller degree of wound opening (2%), together with the better response of the patient during awakening from anesthesia and in the postoperative period.
Saving the amount of time for the procedure (around 20 minutes per procedure), the minimal incision for performing the procedure, the shortened time for wound healing in contrast to the standard medial ovariohysterectomy, the tress hold of pain postoperatively is way lower in contrast to the standard medial technique, the postoperative complications are very rare (infection of the wound, dehiscence of the sutures, postoperative bleeding and pain at the animal itself.