Surgical removal of equine ovarian masses – is less more?

Abstract

This paper describes a retrospective study of 34 mares which had been subjected to surgical elective ovariectomy using a standing laparotomy technique by two experienced veterinary surgeons at 13 different equine clinics in the Netherlands over a 9-year period (2010-2018). Of the 34 mares that underwent surgery, 74 % (25/34) were Warmbloods. Fifty-nine percent (20/34) had a mass in the right ovary and 41% in the left ovary. The primary presenting signs were behavioural and fertility issues. The mean age of the horses was 10 years (5-18 years). The procedure was performed in stocks with continuous infusion sedation and analgesia. Prior to surgery the horses routinely received antibiotics and non-steroidal anti-inflammatory drugs (NSAID's). The surgical site was anaesthetized using an inverted L-block. The paracostal incision was performed in a "grid-or partial grid" fashion. The length of the incision varied from 15-30 cm depending on the size of the mass. The affected ovary was manoeuvred into the laparotomy wound and the ovarian pedicle was infiltrated with local anaesthetic solution. Shortly thereafter the pedicle was crushed with an emasculator and ligated with absorbable suture material. The ovarian mass was removed and the stump inspected for bleeding prior to wound closure in separate layers. The mares remained hospitalized for between 5 and 7 days. The mean diameter of the operated ovaries was 18.5 cm (10-25 cm). Surgical pathology was not always carried out but almost all cases showed a typical granulosa (theca) cell tumour (GCT) appearance and subsequent pathology, in 3 cases, confirmed that diagnosis. All laparotomy wounds healed per primam with only minor postoperative complications (seroma) and no further complications were reported over the following 3 months; all horses returned to their normal activity. Ovariectomy via a standing flank laparotomy is a relative safe, basic, straightforward and economic surgical procedure for the removal of pathologically enlarged ovaries. The procedure requires only restraint, sedation and local anaesthesia with standard, non-specialized instruments. This approach can be considered as a viable and effective surgical option.