Bilateral abscess

1. Schematic representation of posterior horseshoe anorectal abscess: 1. Primary ischiorectal abscess. 2. Horseshoe tract. 3. Secondary subcutaneous abscess.

2. Schematic representation of anterior horseshoe abscess

In this form of anorectal abscess, which is encountered in 10—11 per cent of cases, the pus passes over from the right (or left) ischiorectal fossa to the opposite side, by skirling the anal canal either posteriorly, or, less frequently, anteriorly (Fig. 1 and 2). A primary abscess is in most cases an ischiorectal one , while a secondary abscess on the other side is usually subcutaneous (2). The suppurating horseshoe tract which connects the both abscesses is often rather wide. The internal opening of the abscess is located in the rectum in a posterior (Fig. 1) or anterior (Fig. 2) crypt.

In cases with a horseshoe anoreclal abscess we do not perform sphincterotomy while opening the abscesses so as not to damage the sphincter when the horseshoe tract is wide. Instead, we employ a «postponed» sphincterotomy, that is, we partially divide the sphincter thraugh the internal abscess opening 15—20 days after the abscess was laid open, by which time, the horseshoe trad has considerably decreased in size. No sphincterotomy is performed in women with an anterior horseshoe, these patients being operated on some time later for fistula inano.

3.1 The steps in the operation for horseshoe anorectal abscess: The cavity of one of the abscesses has been opened

3.2 The steps in the operation for horseshoe anorectal abscess: A closed Billroth forceps has been introduced into the horseshoe tract connecting the both abscesses. The forceps end makes the skin bulge over the other abscess

Operative technique. If the abscess is large, it is opened by making a wide incision (Fig. 3,1), and its cavity is swabbed with hydrogen peroxide. A closed Bill-roth forceps is introduced into the abscess horseshoe tract so that the skin over the second opposite is made to bulge by the forceps end (Fig. 3,2). At this point, a second incision is made and the abscess (which as a rule is a subcutanous one)  swabbed with hydrogen peroxide).
Both the abscesses are packed separately with gauze soaked in Vishnevsky ointment (see page 40) or in ointment with Peruvian balsam, and an ointment pack and a gas   evacuation   tube   are   inserted   into   the   rectum
(Fig. 3,3). Dressings are applied each day until a second operation is done 15—20 days after the first one. This second operation is performed in the case the healing of perineal wounds has not been complete and consists in posterior sphincterotomy to a depth of 1 cm in females and 1.5 cm in males (Fig. 3,4). Ointment packs and a gas evacuation tube arc introduced into the rectum, and dressings are applied on the third and fifth days postopcratively.

3.3 The steps in the operation for horseshoe anorectal abscess: The cavities of both the abscesses are filled with ointment packs, and an ointment pack and gas evacuation tube are introduced into the rectal lumen

3.4 The steps in the operation for horseshoe anorectal abscess: Sphincterotomy 3 weeks after the first operation

Packing of the rectal wound is discontinued on the fifth postoperative day, and a liquid Vishnevsky ointment is introduced into the rectal lumen by means of a 2 ml syringe. No sphincterotomy is per formed in women with an arterior horseshoe.