HOW-TO SESSION: FIELD SURGERY - SOFT TISSUE AND WOUND MANAGEMENT


Fig. 2. Inflammed omentum prolapsed through a castration site. Fig. 1. Seroma formation and edema following castration. 3. Infection


dian raphe to facilitate the procedure and establish adequate drainage. Older horses may develop edemamore often when compared to younger horses, which may make them more reluctant to exercise and increase the chances of seroma formation.4 A recent paper has shown that the closed method of castration is less likely to lead to complications when compared to the semi- closed technique.1 The authors of that paper tended to use the semi-closed technique on older horses (mean age, 46 months) and the closed tech- nique on younger (mean age, 18 months) patients. In that study a statistically significant higher per- centage of equids castrated by the semi-closed tech- nique experienced complications (23.5%) than ones in which closed castration was performed (6.1%).1 Seromas may develop several weeks following cas-


tration especially if the incisions close prematurely. If a seroma develops, the horse should be chemically and physically restrained and following aseptic preparation the incision should be manually re- opened and stretched with a sterile-gloved finger. Once adequate drainage is established, broad- spectrum antibiotics and NSAIDs as well as forced daily exercise should be continued until the incisions heal and all swelling subsides. Occasionally a strip of subcutaneous or fatty tis-


sue will protrude from the scrotal incision which can cause owners to worry and may contribute to swell- ing and serve as a nidus of infection. Once the castration is completed and the incisions have been stretched, any subcutaneous tissue that may hang down from the site should be carefully trimmed. Occasionally, a portion of omentum may protrude down from the incision. Following adequate chem- ical and physical restraint, the omentum may be ligated as proximal as possible and safely transected or emasculated (Fig. 2).


If swelling and/or a seroma becomes persistent, especially in the presence of fever or supportive complete blood count (CBC) findings, infection should be suspected (Fig. 3A). Most infections are local and respond to similar treatment as for sero- mas. Long-term drainage may arise from infection of the spermatic cord (scirrhous cord) even months after surgery. The most common bacterial isolates from postoperative castration infections include Streptococcus zooepidemicus and Staphylococcus sp. Preoperative antibiotics and aseptic technique as well as owner compliance are all important in the prevention of postoperative infections (POIs).5 Al- though there are conflicting results in the literature regarding the efficacy of prophlactic antibiotics at preventing infections, the author routinely adminis- ters procaine penicillin G (22,000 IU/kg) approxi- mately an hour before surgery to allow sufficient time for circulation prior to making an incision. Early treatment of incisional infection or seroma will allow management in the field in most in- stances. Establishing adequate drainage by open- ing and enlarging the incisions, lavaging the site with copious amounts of sterile isotonic fluids, and instituting broad-spectrum antibiotics may all be performed either standing or in fractious animals, under injectable anesthesia. NSAIDs should be administered to reduce pain and inflammation asso- ciated with the infection. With established infec- tions of deeper tissues as in scirrous cords surgical debridement of the infected stump and associated fibrous tissue is warranted. Sinus formation may take place over a year after the incisions have healed and will present with persistent serous drainage (Fig. 3B). There is a direct communication along the sper-


matic cord with the abdominal cavity so the poten- tial to develop septic peritonitis exists, though occurrence is rare. Non-septic peritonitis occurs with all castrations and peritoneal nucleated cell counts can be surprisingly elevated without leading


AAEP PROCEEDINGS  Vol. 65  2019 173


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