General anesthesia is usually used, but on occasions local anesthesia may be used. GA affords better examination of the anus and palpation of the sphincter muscles, particularly the internal sphincter.

The lithotomy or prone jackknife position is used, depending on the surgeon’s preference. The prone jackknife position offers a better view of the anus for the operating surgeon and reduces the edema associated with the supine position, and any bleeding usually runs away from the operating surgeon into the rectum. Anesthetists sometimes object to the prone jackknife position, because of the physiological effects on the circulatory system and respiratory system.

Views of the anal canal are greatly enhanced by the use of the operating anoscope such as the Fansler, Eisenhammer, or Parks anoscopes and the addition of a headlight.

The objective of this operation is to establish the anatomy, drain the perianal abscess, and settle the infection. In particular, the surgeon should attempt to identify the presence of an internal opening of a potential fistula at the dentate line, by general pressure on the abscess before incising the abscess.

The abscess is then drained externally, either with a simple radial incision or cruciate incision, any loculations are broken down by the finger, the cavity is lavaged with saline and/or antiseptic, and light packing of the cavity is performed with an alginate dressing. Injecting a weak solution of hydrogen peroxide may further identify an internal opening and hence a fistula.

Some colorectal surgeons prefer the use of a “mushroom” catheter placed in the abscess cavity. If an internal opening is identified, then placement of a loose seton, such as a vascular loop, may be useful. For superficial and submucosal fistulae, abscess drainage can be combined with fistulotomy (laying open).

The most common perianal abscess is either mucosal or intersphincteric indicating their communication between the skin and dentate line, the former being at the level of the submucosa and the latter being through the intersphincteric plane between the internal sphincter and the external sphincter. An ischiorectal abscess forms as an extrasphincteric abscess that has been a communication between the crypt gland level of the dentate line through both the internal and external sphincters with abscess formation in the ischiorectal fossa (see below). The more sphincter that is involved in the abscess formation, the greater the likelihood of longer-term incontinence and the need for care in performing fistulotomy at the initial operation.

The anus has two circular muscles, the internal sphincter (involuntary muscle) and the external sphincter (voluntary muscle) which control muscle tone and fecal/gas control, respectively. The anal cushions are transposed in the 3, 7, and 11 o’clock positions (12 o’clock being anterior) around the anus and carry blood vessels, which can become enlarged and engorged as hemorrhoidal tissue. The anal (crypt) glands lie at the dentate line in the anal canal and communicate with the intersphincteric plane between the internal and external sphincters. Infection of these glands and extension into the ischiorectal fossa may occur. Abscess formation in either of these locations may be evident at the perianal skin surface.

See Table 3.2. Subsequent fistula formation is the most common consequence of this procedure and is the cause of recurrent perianal abscess. Occasionally Fournier’s gangrene may develop in association with perianal abscess, but this is most commonly associated with patients with other significant comorbidities particularly diabetes, immunosuppression, and poor general health. Fournier’s gangrene is often the first presenting problem rather than as a direct postoperative complication of the perianal abscess drainage.

The main potential problem is fecal incontinence, but usually only if the external sphincter is interrupted, for example, when surgery for a high fistula is performed. Other complications are minor. Occasionally, buttock or perianal pain may be significant on defecation after surgery, but usually settles within 5–7 days. Localized cellulitis, recurrent abscess formation, systemic infection, and rarely multi-system organ failure can occur.

General anesthesia is usually used, but on occasions local anesthesia may be used. GA affords better examination of the anus and palpation of the sphincter muscles, particularly the internal sphincter.

The lithotomy or prone jackknife position is used, depending on the surgeon’s preference. The prone jackknife position offers a better view of the anus for the operating surgeon and reduces the edema associated with the supine position, and any bleeding usually runs away from the operating surgeon into the rectum. Anesthetists sometimes object to the prone jackknife position, because of the physiological effects on the circulatory system and respiratory system. Views of the anal canal are greatly enhanced by the use of the operating anoscope such as the Fansler, Eisenhammer, or Parks anoscopes and a headlight.

The objective of this operation is to establish the anatomy, drain the ischiorectal abscess, and settle the infection. In particular the surgeon should attempt to identify the presence of an internal opening by general pressure on the abscess before incising the abscess using an operating anoscope to view the level of the dentate line, being the likely source of the internal opening.

The abscess is then drained externally, either with a simple radial incision or cruciate incision, any loculations are broken down by the finger, the cavity is lavaged with saline antiseptic, and light packing of the cavity is performed. Injecting a weak solution of hydrogen peroxide may further identify an internal opening and hence a fistula.

Some colorectal surgeons prefer the use of a “mushroom” catheter placed in the abscess cavity. If an internal opening is identified, then placement of a loose seton, such as a vascular loop, is preferable to fistulotomy (laying open), as incision may divide the external sphincter muscle and lead to incontinence of feces.

An ischiorectal abscess forms as an extrasphincteric abscess that has been a communication between the crypt gland level of the dentate line through both the internal and external sphincter with abscess formation within the ischiorectal fossa. The more sphincter that is involved in the abscess formation, the greater the likelihood of longer-term incontinence.

The anus has two circular muscles, the internal sphincter (involuntary muscle) and the external sphincter (voluntary muscle) which control muscle tone and fecal/gas control, respectively. The anal cushions are transposed in the 3, 7, and 11 o’clock positions (12 o’clock being anterior) around the anus and carry blood vessels, which can become enlarged and engorged as hemorrhoidal sacs. The anal glands lie at the dentate line in the anal canal and communicate with the intersphincteric plane between the internal and external sphincters. Infection of these glands and extension into the ischiorectal fossa may occur. Abscess formation in either of these locations may be evident at the perianal skin surface.

See Table 3.3. The complications for ischiorectal abscess are similar, but at a higher incidence than for perianal abscess treatment. Subsequent fistula formation is the most common consequence of this procedure and is the cause of recurrent ischiorectal abscess. Occasionally Fournier’s (synergistic) gangrene may develop in association with perianal abscess, but this is most commonly associated with patients with other significant comorbidities particularly diabetes, immunosuppression, and poor general health. Fournier’s gangrene is often the first presenting problem rather than as a direct postoperative complication of the perianal abscess drainage.

The main potential problem is fecal incontinence, but usually only if the external sphincter is interrupted, for example, when surgery for a high fistula is performed. Other complications are minor. Occasionally, buttock or perianal pain may be significant, especially on defecation after surgery, but usually settles within 5–7 days. Initial discomfort is usual after a seton has been inserted, but this usually settles quickly. Localized cellulitis, recurrent abscess formation, systemic infection, and rarely severe sepsis with multi-system organ failure can occur.

General anesthesia is usually used, but on occasions local anesthesia may be used. GA affords better examination of the anus and palpation of the sphincter muscles, particularly the internal sphincter.

The lithotomy or prone jackknife position is used, depending on the surgeon’s preference. The prone jackknife position offers a better view of the anus for the operating surgeon and reduces the edema associated with the supine position, and any bleeding usually runs away from the operating surgeon into the rectum. Anesthetists sometimes object to the prone jackknife position, because of the physiological effects on the circulatory system and respiratory system.

Views of the anal canal are greatly enhanced by the use of the operating anoscope such as the Fansler, Eisenhammer, or Parks anoscopes and a headlight. The objective of this procedure is to carefully examine the anal canal and lower rectum to confirm the diagnosis and divide the internal sphincter by either the closed, open, or combination technique. The left lateral position is usually selected for convenience. Local (long-acting, adrenalin-containing) anesthetic infiltration may be used to define planes, reduce bleeding, and aid postoperative pain relief.

The closed technique uses a no. 11 scalpel and blade placed between the external and internal sphincters through a small skin stab incision, incising the sphincter from outside inward and completing the sphincterotomy by gentle pressure with the finger in a circumferential manner.

The open method incises the perianal skin longitudinally to expose the internal sphincter which is then divided longitudinally under direct vision, using either a scalpel, scissors, or diathermy to expose the external sphincter. The mucosa is then either sutured or left open.

The combination method makes a small radial incision, adjacent to the anal verge, to expose the external and internal sphincters and the planes either side of the internal sphincter are dissected easily with artery forceps or blunt scissors. The internal sphincter is divided using scissors and palpated with the finger to ensure adequate division. Some surgeons prefer to incise the internal sphincter in the base of a fissure; however, scarring and inflammation may make the tissue planes more difficult to define.

The anus has two circular muscles, the internal sphincter (involuntary muscle) and the external sphincter (voluntary muscle) which control muscle tone and fecal/gas control, respectively. The anal cushions are transposed in the 3, 7, and 11 o’clock positions (12 o’clock being anterior) around the anus and carry blood vessels, which can become enlarged and engorged as hemorrhoidal tissue, which may render sphincterotomy difficult. Chronic scarring or perianal sepsis may also alter the anatomy.

See Table 3.4. Sphincterotomy for anal fissure may be performed in a tailored manner, which involves a measured sphincterotomy with division of the internal sphincter relevant to the length of the fissure rather than always dividing the internal sphincter to the dentate line. Sphincterotomy beyond the dentate line will increase the incidence of incontinence, particularly incontinence for flatus.

Bleeding is the most common immediate problem, and this usually resolves spontaneously, though perianal bruising may be a problem and extensive bleeding in the ischiorectal fossa may occasionally occur. Local cellulitis and perianal abscess may occur primarily or secondary to a hematoma. Fistula is rare. Incontinence, particularly incontinence for flatus is the most distressing initial symptom, but usually resolves. Incontinence for feces is not as common, but can occur usually resolving within weeks, but very rarely being permanent. The potential for incontinence and its significant consequences, particularly in women, has been the driver for making this operation a lesser resort after chemical means of relaxing the internal sphincter, such as the use of nitrous oxide inhibitors, calcium channel blockers, and botulinum toxin.

The main potential problem is fecal incontinence, but usually only if the external sphincter is interrupted, for example, when surgery deeply or above the dentate line is performed. Other complications are usually minor. Occasionally, buttock or perianal pain may be significant, especially on defecation after surgery, but usually settles within 5–7 days. Initial bleeding is usual after a sphincterotomy, but this usually settles quickly. Severe bleeding may occur but is rare, although it may require further surgery. Localized cellulitis, abscess formation, systemic infection, and very rarely multi-system organ failure can occur.