Compiled by Dr J.L. Möller BVSc(Hons), MMedVet(Chir)

Sterilisation of the bitch and queen by ovariohysterectomy should be one of the procedures that most veterinary practitioners can perform with self-confidence and finesse, if he or she adheres to the basic rules of surgical asepsis and technique.


Improvisation and adaptation, however, are sometimes required when dealing with very large, overweight patients, patients that have had a caesarean section or other abdominal procedures previously, dystocia cases with retained or decomposed foetuses, pyometra cases, and patients with gravid uterine horns in an inguinal or ventral abdominal hernia.


Certain breeds like the bullterrier, German shepherd and Staffordshire bullterrier tend to have very short and stubby ovarian suspensory ligaments, and the surgeon will require a firmer but more stable hand to stretch the ligament and exteriorise the ovarian pedicle. Different breeds also have differing premedication and anaesthetic tolerances. Highly strung and aggressive animals present a greater anaesthetic risk, and even the recovery period may differ in certain breeds and individual animals.


Although this article will concentrate mainly on the surgical complications of sterilisation, the holistic approach to admission of any surgical patient should be worked out and followed in a disciplined way.




These aspects have been dealt with in previous newsletters, but just to summarise:






The owner should complete an admission form detailing the patient’s past medical history and present health status, and giving consent for the procedure to be performed.
A thorough clinical examination should be performed by the veterinarian or an experienced nurse (not lay staff) and all findings should be recorded.
Undetected subclinical conditions (e.g. long-standing diaphragmatic hernia, especially in a cat) may result in a life-threatening situation when the patient is anaesthetised. A carefully taken history and efficient pre-operative examination will increase the chances of detecting such subclinical conditions.
The anaesthetic protocol should be planned and recorded for every surgical procedure.
Post-operative observation should be performed by well-trained support staff, who can notice, evaluate and interpret the stages and signs of normal anaesthetic recovery, and identify danger signs such as bleeding, respiratory distress prolonged recovery time, hypothermia etc.


Once anaesthesia has been induced and an appropriately sized endotracheal tube has been placed and secured, the anaesthesia should, if at all possible, be maintained by halothane and oxygen inhalation. A cardiac and respiratory monitor will greatly complement your surgical procedures and should give an early warning of problems.


  1. Prepare (clip hair, wash and disinfect) the ventral abdomen from xiphoid to pubis, and from flank fold to flank fold (the area should rather be too big than too small – make provision for possibly having to extend the initial incision). After carefully expressing the bladder, transfer the patient from the prep room to the theatre.

  3. Scrub, gown and glove. Open and pack out the instrument set. Drape the patient. Preferably, the patient and table should be completely covered - only the area around the intended site of incision should be visible. The size of the drape opening is determined by the anticipated procedure and the size of the patient.

  5. Surgical incision – skin, subcutaneous tissue, linea alba and peritoneum. The incision length depends on patient size and the anticipated procedure (e.g. routine ovariohysterectomy, pregnant ovariohysterectomy, pyometra). The incision should rather be too liberal than too conservative. Unnecessary probing and cutting of the rectus sheath and the creation of cavities could result in post-operative inflammation, seroma or haematoma.

  7. When entering the abdominal cavity, beware of a possibly enlarged spleen (splenomegaly with barbiturate induction!), an overfilled urinary bladder or insufficient depth of anaesthesia. The small intestine, omentum or mesentery can prolapse through the wound while the surgeon is making the incision. BLEEDING FROM THE SPLEEN AND MESENTERY, AND LEAKAGE FROM THE BLADDER AND INTESTINES CAN OCCUR WITHOUT THE SURGEON EVEN NOTICING.

  9. Use the ovary hook to search for the uterine horns in the correct abdominal quadrant. No force should be used and the surgeon should be able to distinguish between the fat of the omentum, mesentery and broad ligament of the uterus. The surgeon should familiarise him/herself with the differences in appearance and texture of the round ligament of the uterus and the ureter. Ligation of the ureter will lead to HYDRONEPHROSIS and or PYELONEPHROSIS with likely devastating consequences.

  11. Exteriorisation of the ovary by gentle and careful traction on the ovarian suspensory ligament is a procedure that can only be perfected by experience. Never become complacent with this step. In certain breeds like the bullterrier, German Shepherd and Staffordshire bullterrier, the suspensory ligament tends to be short and very difficult to stretch or break. Overzealous traction can cause haemorrhage where the ligament originates from the middle and ventral thirds of the last one or two ribs. The convoluted left and right ovarian arteries arise directly from the aorta - the tortuousity of these vessels is a built-in safety mechanism against rupturing when subjected to traction. Vascular branches to the adipose tissue and kidney capsule must be kept in mind when ligating the ovarian vessels. Accidental incorporation of omental, mesenteric and/or falciform fat can predispose to LIGATURE SLIPPAGE with immediate or delayed bleeding (blood pressure rises when animal wakes up). SPECIAL CARE SHOULD BE TAKEN WHEN LIGATING THESE STRUCTURES WHEN:








the patient is in oestrus – blood vessels are enlarged and there is a definite bleeding tendency; and
there is uterine infection; and
there are fallopian tube adhesions and infection; and
the patient is overweight; and
the patient has very short, stubby and strong ovarian suspensory ligaments; and
the plane of anaesthesia is too light with insufficient abdominal muscle relaxation;
the abdominal incision is too small or incorrectly placed.

Every surgeon loves a small, neat wound because this is the only evidence of his/her surgical skill that the client sees – the so-called "surgeon’s signature". However, it should be borne in mind that A LONGER INCISION AND SURVIVING PATIENT ARE PREFERABLE TO A TINY WOUND AND EXSANGUINATED PATIENT.

It is obviously very important to remove each ovary completely and this should be verified by opening the ovarian bursa – this small step may well save you the embarrassment of having to deal with the OVARIAN REMNANT SYNDROME. Finding such an ovarian remnant a few months later is not impossible, but requires exposing the patient to additional unnecessary anaesthetic and surgical risk.


  1. Once the ovarian pedicle has been ligated and transected, carefully lift the uterine horn out of the abdominal cavity. Ligate the
  2. mesometerium to prevent oozing from the smaller branches of the uterine artery and vein. In very young and lean patients, bleeding is generally not a problem, but in older and obese patients ligation is mandatory.

    In ovariohysterectomy both ovaries, both uterine horns and the body of the uterus should be removed. The uterine arteries should always be ligated individually in large patients (over 20kg), when the uterus is diseased, and in pregnant and very fat patients. An additional ligature caudal to these individually ligated vessels should encircle the uterine vessels and uterine body (but not include any fat), 0.5 to 1cm from the cervical orifice. WHEN LIGATING THE UTERINE BODY, BLEEDING SHOULD BE AVOIDED AT ALL COSTS. Avoid excessive traction and ensure that the bladder, ureters, colon and fat are not included in any ligature. Time and effort spent here is well-invested because haemorrhage will claim valuable time and result in a blood-filled abdominal cavity. Dealing with bleeding that is totally obscuring your vision can be an extremely stressful experience. IN THE HASTE TO FIND THE POINT OF BLEEDING, IT IS EASY FOR GAUZE SWABS TO FIND THEIR WAY TO A "FORGOTTEN CORNER" OF THE ABDOMINAL CAVITY. Using large abdominal swabs (with tag and radiopaque marker) and suction is a more reliable way of restoring visibility and helps to avoid the STRAY SWAB INTRA-ABDOMINALLY.

    There are many theories on how best to deal with the uterine stump after a caesarean-pan hysterectomy, pyometra or an in-oestrus ovariohysterectomy in a large patient. Thorough cleaning of the stump with sterile Ringers solution, over-sewing the loose ends of the stump and covering it with omentum can minimise granuloma formation by reaction around the stump. Using high quality suture material to tie ligatures will complement your technique and lessen complications - avoid cheap alternatives! Multifilament non-absorbable suture material should never be used because a FOREIGN BODY reaction is inevitable. The resultant SUBLUMBAR DRAINING TRACTS which may develop will force you to search for and completly remove all the ligatures tied with such material. PYOMETRA CAN DEVELOP in the remaining uterine body if too much of this organ is left behind.


  3. Rough handling of the abdominal organs, excessive bleeding, and haematoma formation in the fat of the uterine broad ligament and mesentery, and around the urinary bladder will predispose to intra-abdominal inflammation and infection.
  4. Performing a caesarean section, panhysterectomy with dead or decomposed foetuses, pyometra with perimetritis and leakage of uterine fluid into the abdominal cavity can cause life-threatening sepsis and extensive adhesions between the abdominal organs. POST-OPERATIVE SWELLING AROUND THE UTERINE STUMP SHOULD BE ANTICIPATED when dealing with the above mentioned conditions. HARD GRANULOMATOUS ADHESIONS BETWEEN UTERINE STUMP, URINARY BLADDER AND RECTUM may interfere with urination and defecation, and should be anticipated and handled to prevent pain and misery to the animal.


  5. Suturing the abdominal incision.
  6. Muscle layers: If the initial incision was made correctly through the linea alba, (the midventral strip of collagenous tissue extending from the xiphoid process to the pelvic symphysis), and not incorrectly through the rectus abdominis muscles, BLEEDING AND BLOOD OOZING FROM MUSCULAR VESSELS will be eliminated and sutures should not incorporate the peritoneum. Care should be taken to ensure that the cranial and caudal commissures of the surgical wound are closed properly with a suitable suture pattern using monofilament nylon. According to the literature the incidence of DEHISCENCE will increase if chromic catgut is used and all the muscle layers and peritoneum are included in the sutures. Obliterating subcutaneous dead space by placing 2–4 subcutaneous sutures will prevent SEROMA FORMATION AND WOUND SWELLING, and will ensure an acceptably neat surgical wound with no tension on the skin sutures. INCISIONAL HERNIAS occur acutely within 7 days post-operatively or occasionally weeks after surgery. This embarrassing complication may be caused by fat entrapment, inappropriate suture material, crushing sutures and poor knot tying technique. An inflamed wound, red and swollen with serosanguineus discharge 3–5 days post-operatively may be associated with EVISCERATION. This complication requires aggressive correction and support therapy. Bleeding from the subcutaneous tissue, seroma formation, swelling, skin sutures tied too tightly, and injury of skin around or near the wound, may lead to SELF MUTILATION OF THE WOUND, INFECTION AND FOREIGN BODY REACTION of the subcutaneous sutures with discharging sinus formation.

  7. Animals sterilised when in oestrus should be kept away from male dogs for at least another 12–14 days. When discharging such a patient
  8. from hospital, the owner should hear this message loud and clear. SEVERE DAMAGE CAN BE INFLICTED by the male dog while the patient is still emitting an oestrus odour.


  9. To maintain good client relationships, each owner should be spoken to by the veterinarian or nurse, and their responsibilities explained as
  10. far as wound examination and post-operative care of their pet is concerned. Advice on correct feeding and physical activity, especially in certain inactive breeds (to prevent obesity after sterilisation) is mandatory and will be appreciated by the owners.


  11. When the patient is presented for suture removal, the veterinarian or his nurse will have another opportunity to inspect the wound, palpate

the abdomen, stress the importance of correct feeding and deliberate physical activity, and the vague possibility of urinary incontinence.

Loosing a patient presented for sterilisation is an awful, nightmarish experience and can be extremely detrimental to your practice, your name and the profession. Everything possible within your power should be done to prevent catastrophes and complications, for the sake of our patients, clients, profession, practice and personal peace of mind and job satisfaction.

The last word is still not written about this aspect of our work. Many more complications can be added by surgeons performing these procedures. Let us keep on striving for perfection and only be satisfied with excellence.

Recommended reading:


Current Techniques in Small Animal Surgery

Bojrab MJ (ed). 3rd edition 1990, Lea & Febiger, Philadelphia

Textbook of Veterinary Internal Medicine: Diseases of the Dog and Cat

Ettinger SJ, Feldman EC (eds). 5th edition 2000, W.B. Saunders, Philadelphia

Saunders Manual of Small Animal Practice

Birchard SJ , Sherding RG (eds). 2nd edition 2000, W.B. Saunders, Philadelphia

Reviewed by:

1. Dr W. Venning. Germiston Veterinary Hospital. Tel. No. (011) 902-2506

2. Dr T. Jacobs. Brackenhurst Veterinary Clinic. Tel. No. (011) 867-3631

(Published- September 2002, courtesy of Dr  J L  Möller)


Links to African Council websites

Veterinary Statutory Bodies in Africa

Veterinary Council of Namibia

Veterinary Council of Zimbabwe (department of livestock and veterinary services)

Kenya Veterinary Board

Veterinary Council of Tanzania

Botswana Veterinary Association

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