Chapter 4. Inflammatory Bowel Disease: Surgical Considerations

Ulcerative Colitis

• Surgery is indicated when (1) chronic intractable disease is not controlled with medication, or drug side effects are too severe; (2) patients with severe colitis require an urgent procedure; or (3) dysplasia or cancer is present.
• Most patients needing surgery are candidates for an ileoanal pouch anastomosis (IPAA); the main considerations are age, gender, type of job, and lifestyle.
• In most patients undergoing IPAA, a temporary diverting loop ileostomy is constructed to decrease the likelihood of pelvic sepsis.
• Laparoscopic-assisted and open IPAA give equivalent results.

Crohn Disease

• In general, surgery is indicated for complications (ie, abscess, fistula, perforation, obstruction); considerations include symptom severity, medical treatment failure or side effects, and operative risk.
• Most patients found to have Crohn disease at laparotomy for suspected appendicitis require early ileocolic resection.
• Perianal Crohn disease activity can be assessed using the Perianal Crohn Disease Activity Index.
• Surgical procedures for treatment of fistula-in-ano include fistulotomy, long-term draining setons, and endoanal flap closure, if the rectal mucosa is normal.
• Recent innovative therapy for anal fistula involves adhesive products, fibrin glue, and bioprosthetic plugs of porcine collagen.

The term inflammatory bowel disease (IBD) encompasses a collection of gastrointestinal diseases that medical and surgical specialists treat in a collaborative fashion. Chapter 2 discusses genetic and immunologic factors influencing the development of IBD. Chapter 3 describes medical therapy for IBD. This chapter discusses the indications and types of surgery used for ulcerative colitis and Crohn disease.

In general, these diseases are first treated with medications, and surgery is recommended after medical therapy has been exhausted. However, with certain presentations (eg, anal abscess, toxic colitis), surgery is the first line of therapy, with medication often given after a procedure. Our purpose in this chapter is to survey the surgical procedures used in the treatment of IBD, and to discuss indications and timings relating to their use.

Ulcerative colitis is usually successfully treated medically; however, it is estimated that between 25% and 45% of patients with ulcerative colitis will ultimately require surgery. Surgical therapy is indicated in the following three cases: (1) in patients in whom medication is not controlling the disease, or side effects of the medication are too severe to be endured; (2) in patients with severe acute colitis requiring an urgent procedure; and (3) in patients with either cancer or dysplasia of the colorectal mucosa. Given that ulcerative colitis is a disease limited to the colon and rectum, one needs to remember that it is possible to "cure" this disease with surgical intervention. Further, in most patients, success rates of surgical therapy are high, and sphincter-sparing options exist. Despite the use of new therapies such as infliximab, the incidence of surgery has not significantly changed in the past few years.

Before discussing the specific indications for surgery, several general issues relating to the patient with colitis need to be reviewed.

IPAA or Ileostomy?

When surgery is recommended for a patient with colitis, the surgeon needs to assess whether the patient is ultimately a candidate for a sphincter-sparing surgery that avoids a permanent ileostomy. Most patients are candidates for an ileoanal procedure (see later discussion), but some are not. The main considerations in determining whether a patient should have an ileostomy or a sphincter-sparing procedure include age, gender, type of job, and lifestyle. For example, an older woman who has had several children may at presentation to the surgeon already have some fecal incontinence issues. As difficult as it may be for the patient's body image, recommending an ileoanal procedure in this patient would do her a disservice because it is highly likely that there would be significant fecal leakage and hygiene issues. Further, if a patient has a job or hobby that does not allow for access to a bathroom, an ileostomy may provide for a better quality of life than an ileoanal procedure.

Emotional Support and Education

When surgery is recommended, the patient—and on occasion the medical team—may feel a sense of failure. In addition, the patient often has a significant fear of the procedure and the possible need for a permanent ostomy. The medical team, surgeon, and support staff need to be cognizant of this perception. Reassurance and education about the upcoming process is the best approach to the patient at this time. Availability of support staff, such as an ostomy nurse, and discussions with previous patients who have undergone the procedure are extremely helpful in improving the patient's outlook on the surgery.

Immunosuppression

The ill colitis patient is often referred to the surgeon after all immunosuppressive options have been exhausted. Surgical outcomes in avoiding infection and with wound healing can be significantly affected by immunosuppressive medications. The gastroenterologist, surgeon, and patient should discuss whether any medications can be stopped before the procedure without risk of a significant disease flare. It is not realistic to wean a patient off all immunosuppressive medications prior to surgery. In particular, many patients require and should remain on corticosteroids if these medications are necessary to avoid a significant exacerbation of a flare. Although patients undergoing surgery for inflammatory bowel disease are at increased risk of developing surgical site infections, recent studies have shown that the addition of biologics to the treatment of ulcerative colitis has not increased the risks of postoperative complications.

Nutrition

IBD and especially severe colitis can lead to weight loss, protein loss, and malnutrition. Intravenous nutrition preoperatively and perioperatively is essential in the most severe cases. Choice of operation is also affected by the nutritional status of the patient.

Medical Comorbidities

Although colitis usually affects younger patients, the medical comorbidities of the patient need to be reviewed because they may affect the type of procedure recommended. In particular, patients with colitis seem to have an increased incidence of thrombotic complications in the postoperative period; therefore, a low threshold should be set for investigating any preoperative risk for venous thrombosis either of the extremities or the intestinal venous system.

Bowel Preparation

Bowel preparation is recommended in any patient undergoing a colon resection. Recent studies have shown that mechanical preparation is not necessarily associated with a decreased risk of infectious complications. These studies, however, have been performed on the "average" colon patient and not on the subset of colitis patients with the issues already noted. We therefore recommend, when possible, that colitis patients undergo mechanical bowel preparation followed by administration of perioperative antibiotics to cover aerobic and anaerobic bacteria.

Indications for Surgery

Acute Colitis

Ideally operations for ulcerative colitis should be performed in a staged and deliberate manner. However, some patients develop severe acute colitis, requiring emergent surgical intervention.

Acute colitis is a term used to describe a series of signs and symptoms that include rapid onset of abdominal pain, bloody diarrhea, abdominal distention and tenderness, anorexia, fever, tachycardia, leukocytosis, and low urine output. It is important to remember that most of these patients use corticosteroids and other immunosuppressive agents that may mask the severity of many clinical symptoms. Severe colonic dilation or toxic megacolon is a feared complication of therapy that can lead to perforation, stool spillage, sepsis, and even death. Although acute colitis may occur in patients with known ulcerative colitis, it can also present as the heralding sign of colonic pathology in a patient not previously diagnosed with ulcerative colitis. Surgery is indicated for patients who exhibit signs of visceral perforation, generalized peritonitis, sepsis, or massive gastrointestinal bleeding. In addition, patients who do not improve despite maximized medical therapy after approximately 72 hours often require emergent operation. Other patients who improve with medical treatment while NPO but who then deteriorate once an oral diet is resumed often require surgery. The differential diagnosis of acute colitis includes Clostridium difficile infection, infectious diarrhea, and cytomegalovirus colitis. These conditions can coexist with and complicate ulcerative colitis. It is important to rule out these diseases, when possible, because their successful medical treatment can avoid an urgent or emergent surgical procedure. At times, however, the combination of baseline colitis and these secondary colitides necessitates an emergency procedure.

The choice of operation for an emergent procedure is discussed later in this chapter. In most cases, the goal of the surgeon is to "get in and get out." Typically, a total colectomy with ileostomy and Hartmann pouch (the oversewn rectum) is performed. This procedure can be completed quickly, removes about 90% of the large intestine, and avoids a complex pelvic dissection and anastomosis. The procedure also does not eliminate further treatment options for the patient; for instance, a sphincter-sparing ileoanal anastomosis can still be performed at a later date.

"Subacute" Colitis: Failure of Medical Therapy

Subacute colitis describes a disease pattern in which the patient is neither acutely ill with an unmistakable indication for resection, nor in remission and symptom free. Patients who experience symptoms of chronic intractable disease such as recurring acute colitis, steroid dependence, chronic fecal urgency, growth retardation, persistent active disease, or complications of medical therapy (eg, diabetes, hypertension, peptic ulcer disease, psychosis, myopathy, osteonecrosis, and cataracts) often benefit from surgical intervention. The long-term side effects of some of the new biologic medications have not yet been determined, and the patient, gastroenterologist, and surgeon need to balance the risks of long-term medical therapy against those of surgery. Again, it should be emphasized that one can "cure" ulcerative colitis with surgery, and most patients have an excellent quality of life without the need for medications. However, a small percentage of patients fail surgical therapy with a sphincter-sparing procedure and require an ileostomy, and some develop pouchitis, a postoperative condition that is rarely debilitating but can require chronic treatment.

Dysplasia or Cancer

In addition to failure of medical management, dysplasia or cancer is an indication for surgery in patients with ulcerative colitis. Patients with IBD are at increased risk of colorectal cancer (CRC). The risk of CRC in ulcerative colitis depends on the duration and extent of disease. A population-based study in the United States estimated the risk was significantly increased in those with extensive disease or pancolitis (standardized incidence ratio [SIR] 2.4, 95% CI 0.6–6.0). In addition, patients with ulcerative colitis complicating primary sclerosing cholangitis (PSC) may be at increased risk for CRC compared with those without PSC. A case-control study in which cases and controls were matched for the extent and duration of disease found that the risk of CRC was reduced with use of anti-inflammatory agents (including aspirin, nonsteroidal anti-inflammatory drugs, and 5-aminosalicylic acid [5-ASA] agents) and by surveillance colonoscopy, while it was increased in patients with a history of postinflammatory pseudopolyps.

Patients with disease extending to the hepatic flexure or more proximally have the greatest risk of CRC. Compared with an age-matched population, the risk begins to increase 8–10 years after the onset of symptoms. The approximate cumulative incidence of CRC is 5–10% after 20 years and 12–20% after 30 years of disease. Lower rates of CRC have also been found. In a population-based study from Copenhagen, the risk of CRC was not different from the general population, a finding that the authors hypothesize may have been due to an active surgical approach in medical treatment failures and long-term use of 5-ASA drugs. The highest cancer risks have been reported by medical centers that predominantly receive referral patients who may have more severe or long-standing disease.

In one series, the absolute risk of CRC in patients with pancolitis was 30% after 35 years of disease. The risk was increased in those with the onset of symptoms prior to age 15. However, in other reports, the age of onset of colitis did not increase the risk of CRC after adjusting for the longer period of time that young patients were at risk and the extent of the disease.

Most studies have found that the risk of CRC increases after 15–20 years (approximately one decade later than in pancolitis) in patients with colitis confined to the left colon (ie, distal to the splenic flexure). However, rates of CRC and dysplasia similar to those seen in patients with pancolitis have been described. Patients with ulcerative proctitis and proctosigmoiditis are probably not at increased risk for CRC. Although optimal surveillance strategies for colon cancer in patients with IBD have not been established, the following recommendations for patients with ulcerative colitis have been issued by major national medical societies in the United States.

American Gastroenterological Association (AGA)

The AGA recommends that colonoscopic surveillance begin after 8 years in patients with pancolitis, and after 15 years in patients with colitis involving the left colon. Colonoscopy should be repeated every 1–2 years.

American College of Gastroenterology (ACG)

The ACG recommends annual surveillance colonoscopy beginning after 8–10 years of disease in patients who are surgical candidates. Multiple biopsies should be performed at regular intervals. The finding of definite dysplasia (of any grade) should be confirmed by an expert pathologist and is an indication for colectomy. Patients whose biopsy specimens are indefinite for dysplasia after review by an expert pathologist should undergo repeat surveillance colonoscopy at a shorter interval. The ACG recommendations do not specify whether surveillance can begin later in patients with disease limited to the left colon.

Surgical Options

The choice of operation(s) for a patient with ulcerative colitis is dependent on the presenting condition (emergent vs urgent vs elective), general issues previously discussed, and the experience of the surgeon. There are three eventual choices for the patient: (1) proctocolectomy and creation of an ileoanal anastomosis with a pouch (IPAA), (2) proctocolectomy with end ileostomy, and (3) continent ileostomy (Koch pouch or variation).

Another surgical issue is how to stage these procedures. Can the procedure be completed in one operation, or does it require a two-stage or three-stage approach? Finally, in patients undergoing IPAA, should the anorectal mucosa that lines the sphincter complex and distal rectal wall just proximal to the dentate line be "stripped," or should 0–3 cm of this mucosa be left intact and the pouch stapled to this anorectal cuff?

Many factors are taken into account when the surgeon and patient choose an operation, including age, comorbidities, patient size, extent of disease, and patient preference. Ultimately, however, surgery results in complete removal of the colon and rectum, and near complete removal of the proximal anal mucosa, which effectively eliminates the disease.

Emergency Surgery

When an emergency operation is indicated, the best surgical option consists of total colectomy, end ileostomy, and the Hartmann pouch (stapling or sewing off the stump of the rectum). As mentioned, this procedure avoids a pelvic dissection, removes most of the large intestine, avoids an anastomosis, and does not eliminate any future options. The procedure also is used in patients in whom the diagnosis of ulcerative colitis is not clear. If the differential diagnosis includes Crohn disease, indeterminate colitis, or C difficile or other infectious colitis, this procedure should be performed; the eventual surgical choice can then be discussed after the pathologist has been able to examine the whole specimen. On extremely rare occasions, the surgeon's only option is a diverting ileostomy. The only indication for this procedure is a patient who is hemodynamically unstable on the operating room table.

Ileoanal J Pouch Procedure

In the ileoanal J pouch procedure, the colon and rectum are removed in either one or two stages, and a reservoir is created using the distal ileum. This reservoir or pouch is then anastomosed to the anus in one of two ways: either with a hand-sewn anastomosis combined with stripping of the distal rectal mucosa down to the dentate line, or with a specialized stapling device that leaves 0–3 cm of distal rectum. The pouch procedure (IPAA) is a very attractive option because it not only removes the diseased areas, but it also allows the patient to remain continent and with normal anal defecation. It is usually performed as a two-stage operation: the first stage involves a complete proctocolectomy with ileoanal J pouch anastomosis and temporary diverting ileostomy, and the second (final) stage involves removal of the diverting ileostomy and restoration of intestinal continuity. The IPAA can also be performed after a patient has had emergency surgery (see later discussion). Once a patient has recovered sufficiently, both medically and psychologically, from an emergency total colectomy, the surgeon can proceed to removal of the remaining rectum and creation of the pouch.

The purpose of the pouch in the IPAA is to provide a reservoir for stool as a means of decreasing the frequency of bowel movements. When the ileoanal procedure was first performed, creation of the pouch was not part of the procedure. Instead, the patient would have a "straight" ileoanal anastomosis. However, stool frequency during the first year following surgery was extremely high—as many as 20 times per day. Although the frequency diminished after 1 year, the pouch procedure was added to the ileoanal anastomosis to correct this functional problem.

There are several different configurations for an ileoanal pouch. The most common shape is the J pouch, so named because it resembles the letter "J." The J pouch is created by folding the end of the oversewn ileum back on itself by 12–15 cm and then creating a common channel between the limbs via the apex of the J. The procedure can be performed with a surgical stapling device, which is quick and reliable. The pouch has an increased capacity, which then allows for a decreased frequency of bowel movements. The J pouch is anastomosed to the anus or very distal rectum through the opening at the apex that had been used to create the reservoir.

Several other pouch configurations (S, W, Q, etc) exist; however, one pouch shape rarely has an advantage over another. The S pouch is the only other configuration that is commonly used. To create an S pouch, the distal ileum is folded on itself three times for 8–10 cm, with the most distal limb having a short "spout." The spout is anastomosed to the anus. The key technical issue with the S pouch is to make sure the spout is not too long, since this can lead to difficulties in emptying of the pouch. Typically the spout is no longer than 2 cm.

In most patients, after creation of the pouch and the ileoanal anastomosis, a temporary diverting loop ileostomy is constructed. The goal is to decrease the pelvic sepsis rate from a suture line leak either at the ileoanal anastomosis or along the suture or staple lines of the pouch. Pelvic sepsis rates are decreased significantly when a temporary diverting ileostomy is used. Because pelvic sepsis can lead to poor pouch function and, in women, can lead to significant rates of infertility, the diversion is nearly always performed (ie, in >95% of all patients undergoing IPAA). In carefully selected patients, however, this temporary diversion can be eliminated. These patients tend to be thin and well nourished, tend to undergo a stapled anastomosis, and are not receiving immunosuppressive medications.

Total Proctocolectomy and End Ileostomy

The IPAA is not suitable for all patients. For example, in patients who do not have sufficient anal sphincter function, an ileoanal J pouch may lead to involuntary soilage and leakage of stool. In these patients, the best surgical option is proctocolectomy with end ileostomy. This procedure removes all of the large bowel, including the colon, rectum, and anal glands, which are lined with columnar mucosa, thereby removing any subsequent risk of inflammation or carcinoma. It is usually performed as a one-stage procedure and, because there are no suture or staple lines, is often performed without major septic complications.

The disadvantage of the procedure is that it obligates the patient to a permanent ileostomy. Any stoma can have an effect on the patient's body image; however, this decrease in quality of life is counterbalanced by the overall increase in well-being that results from elimination of the disease. Additionally, for patients who have had problems with fecal incontinence, an ostomy can bring a significant improvement in quality of life.

Total proctocolectomy and end ileostomy are indicated in the following cases: poor anal sphincter control, those who need postoperative chemoradiation for cancer treatment, body habitus (ie, obese patients) that precludes an IPAA, prior small bowel resection, severe dysplasia in the distal rectal mucosa, and patient preference.

Continent Ileostomy

Another surgical option for patients with ulcerative colitis is total proctocolectomy and continent ileostomy. This procedure combines a total proctocolectomy with complex pouch and nipple configuration of the distal ileum. The nipple valve is sutured flush with the abdominal skin, and the pouch is then emptied using a catheter at regular intervals. Although ideal in theory, the continent ileostomy is associated with many complications, including fistulization, valve necrosis, prolapse of the valve, extrusion of the valve, dessusception, and incontinence. Additionally, the continent pouch uses significant amounts of distal ileum and if revised or removed, can result in significant loss of small bowel. This procedure is usually performed only at specialized centers, and its complexity and complication rate make it the third choice for patients who need surgery for colitis.

Laparoscopic Approach

As with all colonic surgery, laparoscopic techniques can be applied to surgery for ulcerative colitis. The use of laparoscopic instruments does not, however, lead to a significant difference in hospitalization. Although the time to discharge may be decreased in patients undergoing a segmental colon resection, in those undergoing total colectomy or total proctocolectomy, the length of stay is often the same for both laparoscopic and open surgery. The laparoscopic procedure does have some advantage in cosmesis. The overall length of the small incisions is less than the incision length for open surgery, and sometimes the main laparoscopic incision can be placed low on the abdomen in a transverse manner so it can be hidden below a belt or panty line. The laparoscopic procedure is best reserved for thin patients who are undergoing an elective procedure. Larson and colleagues studied the functional outcome of laparoscopic-assisted versus open IPAA and found equivalent results for frequency and consistency of stool, medication usage, daytime and nocturnal incontinence, and quality of life in regard to social life, home life, family, travel, sports, recreation, and sex life.

Fertility Considerations in Female Patients

Female patients requiring restorative proctocolectomy are usually in their reproductive years at the time of surgery. Cornish and colleagues reviewed the effect of restorative proctocolectomy on sexual function, urinary function, fertility, pregnancy, and delivery. They found that the incidence of dyspareunia increases after restorative proctocolectomy. There was a decrease in fertility, although pregnancy was not associated with an increase in complications. Vaginal delivery is safe after restorative proctocolectomy, and pouch function after delivery returns to pregestational function within 6 months.

Crohn disease can affect the entire gastrointestinal tract, from mouth to anus. It may be confined to the colon alone or involve only the anal canal. Segmental involvement, rectal sparing, fistulas, perianal disease, strictures, and abscess formation are all characteristic of granulomatous colitis. Characteristic "fat creeping" (subserosal extension of fat around the surface of the bowel) and prominent vascularity in the serosa are characteristics of the disease seen on gross inspection. The disease usually affects the bowel in a segmental fashion, leaving so-called skip lesions. Ulcerations and bowel wall thickening occur with areas of sparing in between pathologic areas. Fistulas often form in Crohn disease and may involve small or large bowel, bladder, vagina, uterus, ureter, or skin, most commonly originating from the mesocolic (rather than antimesocolic) border of the bowel. Histologically, the three primary findings in Crohn colitis are transmural inflammation and fibrosis, granulomas, and narrow, deeply penetrating ulcers or fissures.

Although the majority of patients with Crohn disease require surgery during the course of their disease, the indications for surgery are not completely clear-cut. In general, surgery is indicated primarily for complications of the disease, including abscess, fistula, perforation, and obstruction. The decision to operate involves consideration of symptom severity, medical treatment failure or side effects, and operative risks.

Ileocolic Disease

Ileocecal Crohn disease may masquerade as appendicitis. Traditionally, patients found to have terminal ileitis at laparotomy for presumed appendicitis, and who have a normal cecum, undergo appendectomy, leaving the diseased ileum in place. However, recent studies demonstrate that the majority of patients found to have Crohn disease at laparotomy for appendicitis required early ileocolic resection; therefore, the traditional advice to leave the diseased bowel in place may be reconsidered.

The ileocecal region is the most common site of Crohn disease. The diagnosis of ileocolic Crohn disease may be delayed up to 1 year. The second surgery rate for ileocolic disease is 44% over 10 years, but this rate may change with the introduction of biologics and other therapies given postoperatively as "maintenance" therapy.

Strictures & Fistulas

The rectum and anal region can be involved in this chronic inflammatory bowel disease (Figure 4–1), either together (as rectal and perianal Crohn disease) or as separate entities, and the perianal disease often heralds the onset of intestinal symptoms of Crohn disease (see Figure 9–23). Perianal disease on its own has a better prognosis than disease associated with rectal involvement. However, it is important that definitive diagnosis be confirmed by histologic examination, as ulcerative colitis and Crohn disease share similar features. Perianal involvement is present in 3.8–80% of patients, as seen in literature reviews (refer to Armuzzi and colleagues; McClane and Rombeau, listed later), and it recently has been cited as a distinct phenotype of Crohn disease by identification of a susceptibility locus on chromosome 5.

There is a wide spectrum of presentation of perianal disease, with the perianal skin appearing bluish in active disease. Superficial ulcers may extend into the anal canal or be present on edematous fleshy tags protruding from the anal verge. These ulcers may be painless, whereas deep cavitating ones in the upper anal canal can be painful, causing abscesses and fistulas. The anus can be distorted with fistulating disease and is sometimes described as a "watering can anus." Pain and swelling are common findings, and individuals with fistulas have persistent purulent discharge, pain, and possibly bleeding as well as fever and a preceding history of abscess development. The external opening on the skin is evident, and on digital rectal examination, anoscopy, or proctoscopy, an indurated area in the anal canal corresponding to the internal opening may be obvious. The involved rectal mucosa has a characteristic thickened, nodular feel and a congested and granular appearance.

Perianal lesions are classified as primary or secondary. Primary lesions comprise anal fissure, ulcerated edematous pile, cogitating ulcer, and aggressive ulceration. Secondary lesions consist of skin tags, anal or rectal stricture, perianal abscess or fistula, fistulas of the vagina or bladder, and carcinoma.

An assessment of perianal Crohn disease activity can be made using the Perianal Crohn Disease Activity Index (Table 4–1), which looks at discharge, pain, restriction of sexual activity, type of perianal disease, and degree of induration. Other scoring systems also are available that require additional evaluation. A thorough assessment of intestinal pathology should be undertaken to determine the extent and severity of the disease, because terminal ileal disease sometimes manifests as a perianal fistula, and at other times, medical treatment of intestinal disease improves the outcome or healing of local surgery of perianal disease.

Indications for Surgery

Traditionally, owing to poor or delayed healing, a conservative approach to the management of perianal Crohn disease has been followed. Surgical procedures range from simple suppurative drainage to proctocolectomy and ileostomy, the latter reserved for intractable disease or complications associated with intestinal disease.

Indications for local surgery in perianal Crohn disease are limited to the drainage of pus in abscesses, bothersome fistulas-in-ano that are refractory to medical or nonsurgical management, rectovaginal fistulas, and, in severe proctitis, anal stenosis, or severe recurrent abscesses, proctectomy.

It is important to note that medical therapy alone or surgical therapy alone does not have as high a success rate in the treatment of anal fistulae in Crohn disease as does a combined approach. Surgery, antibiotics, and medical therapy, especially the use of infliximab, used in sequence or combination have shown the best results.

Surgical Options

Incision & Drainage of Abscesses

A common emergency presentation of perianal Crohn disease is abscess formation requiring incision and drainage to allow maximum drainage of sepsis (Figure 4–2). Appropriate antimicrobial cover is needed when significant cellulitis surrounds the abscess, or the patient is immunocompromised or has cardiac valvular pathology. A cruciate incision or an elliptical excision of skin overlying the area of maximum fluctuance is undertaken under general anesthesia if the abscess cavity is large. Any loculations are then gently broken up with a digit, and the wound is loosely packed (Figure 4–2A). This approach should suffice for superficial abscesses. For deep or high abscesses, placement of a mushroom or Malecot catheter allows adequate drainage and thus prevents premature closure of the surgical incision (Figure 4–2B).

At this time an examination to find any fistulas is undertaken under anesthesia. Usually a probe is inserted through the external opening to delineate the fistulous tract. If any resistance to the passage of the probe is encountered, care is taken to avoid creating false passages. If the internal opening is not evident, injection of dilute methylene blue dye or hydrogen peroxide into the external opening with an angio-catheter may facilitate visualization. The track, if found, is curetted, and a loose seton is inserted to allow drainage. The seton is a thread of foreign material that is passed through a fistula tract and tied into a loop. (Silastic tubing or a vessel loop is preferred because they are soft and can remain in place for prolonged periods.) Drainage of sepsis decreases the risk of further abscess formation and avoids iatrogenic incontinence due to division of any sphincteric muscle, particularly in high anal fistula.

These simple procedures alleviate pain and improve the quality of life in most patients. They also permit magnetic resonance imaging or endoanal ultrasonographic imaging of the anus to delineate more complex fistula tracks or distorted anorectal anatomy. Later, as the sepsis resolves, a more definitive surgical procedure can be undertaken.

Some patients require long-term seton drainage because of the risk of complications that may occur with surgery (eg, delayed wound healing and incontinence). However, healing of the perianal pathology occurs with removal of the seton in some patients.

Surgical Management of Fistulas

Surgical procedures for treating fistula-in-ano in patients with Crohn disease vary, depending on the severity of symptomatology and the complexity of the fistulous track. The following guidelines are suggested: (1) Asymptomatic fistulas need not be treated immediately. However, they often reclose at the level of the skin, and placement of a draining seton is often required to keep the tract open. (2) Simple, low fistulas may be treated by fistulotomy. (3) Complex fistulas may be well palliated with long-term draining setons. (4) Complex fistulas may be treated with advancement flap closure if the rectal mucosa is grossly normal or with placement of a porcine plug, and on rare occasions, a Crohn fistula can be treated with a LIFT (ligation of intersphincteric fistula tract) procedure.

Fistulotomy

Fistulotomy involves laying open the fistula tract and merging it with the anal canal. This allows the tissues to heal from the inside out. Primary fistulotomy in Crohn disease patients with low, simple fistulas demonstrates excellent healing rates, particularly in the absence of rectal disease. The procedure is contraindicated for complex and high fistulas where division of a large proportion of the anorectal sphincter would be necessary.

When a fistula occurs anterior to the anal canal in a woman, primary fistulotomy almost invariably causes some degree of fecal incontinence. Wound healing occurs in 3–6 months, and complications of fecal incontinence and anal stenosis have been reported. In complex cases, a more conservative surgical approach is taken to minimize the risk of incontinence, by using a noncutting or draining seton. Medical therapy can also be instituted, thus reducing the risk of recurrence. One report found that 85% of patients treated with noncutting setons experienced fistula closure; however, rates of fistula recurrence may be as high as 39% after removal of noncutting setons, highlighting the need for concomitant medical therapy with antibiotics, azathioprine, or 6-mercaptopurine and infliximab. More than one seton may be placed if multiple tracts are present, although fecal seepage and drainage along the seton can be problematic.

In patients with rectal-sparing disease, endoanal or rectal flaps are advocated. These flaps are advantageous because they avoid the risk of incontinence, problems of open wounds, and possibly poor healing that may occur in the presence of sepsis. Apart from flap failure, few complications are seen. Thus, fistulotomy can be performed as a primary procedure or following seton drainage with the use of flaps or interposition grafts.

For longer, more complex fistulae with no evidence of anal sepsis, a porcine plug can be placed in the tract. The tract is usually curetted of all granulation tissue, and the plug is sutured to the anorectal wall with the rectal mucosa covering the plug (see below). A new procedure called a LIFT technique can also be used. The surgeon divides the fistula tract in the intersphincteric groove. All of these techniques for complex fistulae have a lower success rate with Crohn disease. Success is improved when there is no evidence of anorectal sepsis and with quiescent rectal disease.

Endoanal Advancement Flap

An endoanal advancement flap consists of anal mucosa, submucosa, and usually part of the underlying circular muscle. The base of the flap should be twice the width of its apex to ensure adequate blood supply for healing. The optimal depth of the flap is controversial; some surgeons believe that the flap should entail the full thickness of the rectal wall to reduce the chance of flap failure. The fistula tract is cored out or curetted before mobilization, and suturing of the flap distal to the internal opening of the fistula is carried out. Any secondary tracts can be treated by curetting or laying open the tract.

A curvilinear mucosal flap is most commonly used. It involves a semicircular incision starting at the dentate line and continuing proximally for 4–5 cm. The fistula tract is cored out, and the fistula is closed in layers, with mobilization of the flap. The diseased distal portion of the flap is trimmed before the flap is sutured to the mucosal edge of the anus.

If the location of the fistula is high, or there is too much tension on the flap, a linear mucosal flap is used. In this repair, the fistula tract is excised in a linear fashion perpendicular to the dentate line. The defect is closed in layers. The mucosa and submucosa are mobilized on each side and sutured together.

An anocutaneous flap is another option for closing the internal opening. It has the theoretical advantage of not involving any sphincter and can be a more feasible option than an endoanal flap if the internal opening is located distally or if the anal canal is changed by stenosis or scarring after previous surgery or inflammation. The sleeve advancement flap originally described by Berman has also been used to treat anal stricture and a combination of rectal and perianal fistulas.

Using these variations of flaps, healing rates of 68% have been achieved for a curvilinear rectal flap in scenarios of minimal rectal-sparing disease and for rectal ulceration, a sleeve flap and a linear flap for high rectovaginal fistula. Based on a literature review, Sher and colleagues advised using a transvaginal approach to develop a vaginal flap with a protective defunctioning ileostomy for the management of rectovaginal fistula in patients with Crohn colitis. They achieved a success rate of 93% in their series of patients. In cases of high rectovaginal or colovaginal fistula, an approach via the abdomen would be preferable. However, in intractable disease, some women may choose to accept residual fistula drainage over proctectomy or stoma formation.

Fecal Diversion

Diversion of the fecal stream by the creation of an ileostomy or a colostomy has been employed to manage anal fistulas in Crohn disease, an approach first reported by Truelove. A loop defunctioning stoma, which should be easy to reverse, is constructed either laparoscopically or by open surgery. The decrease in fecal flow through the rectum and across the fistula tract allows the rectal mucosa to heal and the fistula to close. Creation of the stoma may improve the results of subsequent anal procedures, and also allows the patient to adjust to the prospect that life with a stoma is feasible. Symptomatic improvement after diversion is not predictable, and new manifestations of perianal Crohn disease can develop. Approximately 50% of patients with symptomatic perianal Crohn disease require permanent fecal diversion.

There are limited indications for fecal diversion in Crohn disease. These include severe perianal sepsis, deep persistent anal ulceration, and complex anorectal or rectovaginal fistula, as well as complications refractory to medical and local surgical measures. In some patients, fecal diversion can be considered before commencement of combination medical therapy. Initially there is a high rate of perianal healing with reversal of the stoma in patient with rectal-sparing disease. However, in individuals with rectal or colonic Crohn involvement, restoration of bowel continuity almost invariably leads to recurrence of perianal symptoms, eventually necessitating proctectomy.

Proctectomy

Patients with active anorectal disease that fails to respond to medical and previous surgical therapy may require proctectomy with end colostomy. Rates of 10–18% have been reported. Patients who also have colonic involvement require proctocolectomy with permanent end ileostomy. In ill or high-risk patients, this may be performed in two stages, with colectomy and end ileostomy comprising the first procedure, followed by completion proctectomy. In contrast to an abdominoperineal resection for rectal cancer, an intersphincteric dissection may be considered for the perineal component, as this leaves a smaller, more vascularized wound that heals with less morbidity. However, deep fistulating disease or sepsis may make this impossible. When a tension-free closure is not possible, the use of rectus abdominis, gluteal myocutaneous, and gracilis transposition flaps promote healing.

A recognized complication of proctectomy is a persistent perineal sinus. In such cases, it is important to rule out pelvic sepsis or an enteroperineal fistula, which would require resection of the affected bowel. Some patients experience phantom sensations after proctectomy that are analogous to those occurring after limb amputation. Explanation and reassurance is usually sufficient to allay patients' concerns. Persistent perineal pain after proctectomy can be troublesome and may be caused by a neuroma.

Patients with long-standing Crohn disease, like those with ulcerative colitis, are at increased risk (3.7%) of developing adenocarcinoma as well as squamous cell carcinomas. This increased risk has been attributed to an early onset and prolonged duration of disease. The incidence of carcinoma is 0.7% in patients with perineal Crohn disease. Patients with adenocarcinoma require proctectomy. Those with squamous cell carcinoma may be considered for chemoradiotherapy; however, the functional outcome may be unsatisfactory. Therefore, proctectomy may be the preferred option. The diagnosis is usually made based on examination of biopsy specimens and brushings of the curetted fistulous tract.

Other Techniques

Recent innovative therapy involves the use of adhesive products. Several studies have reported on fibrin glue treatment of anal fistula using both autologous fibrin tissue adhesives and commercially available fibrin glue. The adhesive is instilled in the fistula tract after curetting, and sometimes irrigation of the tract, to allow glue adhesion to the tissue. Insertion of the fibrin glue is continued until glue appears at the internal opening of the fistula. The sealant not only acts as a closing plug for the fistula, but also as the substrate for the in-growth of fibroblasts. The technique is not suitable for fistulas with extensions.

The reported success rates in patients have varied from 40% to 85%, with a mean of 67% for the various materials. Buchanan and colleagues reported long-term healing of only 14%, whereas Sentovich showed a healing rate of 60% when all patients had a draining seton preoperatively and the internal opening was closed with a suture at the time of glue instillation. In a later review by Swinscoe and colleagues of 12 studies, the overall healing rate was 53%. However, in patients with Crohn disease, fistula results have been considerably lower. Recent data have shown no value in using fibrin glue over fistula surgery without glue. Currently, we do not recommend or use fibrin glue for the treatment of fistulae. The use of human granulocyte colony-stimulating factor instead of fibrin glue has been shown to heal perianal Crohn-associated fistula in some patients.

Johnson and colleagues introduced a new method of closure for anal fistula with a bioprosthetic plug. The conically shaped plug, made of porcine collagen, is pulled into the primary tract through the internal opening until it fills out the whole length of the tract. Both ends of the plug are secured with sutures, and at the internal opening, the end of the plug is covered with mucosa and also preferably with internal sphincter. The remaining external opening is left open for drainage. Champagne and colleagues reported a success rate of 83% with a median follow-up of 12 months for high cryptoglandular anal fistulas, and the method has also been used in a smaller group of patients with Crohn fistulas reported by O'Connor and colleagues. However the exact place that these modalities have in the management of Crohn fistula remains unclear, but their use does not preclude other surgical procedures should the treatment fail.

Asymptomatic fissures, hemorrhoids, and skin tags in Crohn patients should be left alone, and if surgery is requested, the patient should be informed of complications such as poor healing, stenosis, incontinence, and ulcer formation. Anal ulcers are likely to be worsened by surgery, and a trial with medical therapy should be instituted to promote healing. In refractory symptomatic anal fissures without proctitis, lateral sphincterotomy is indicated. Symptomatic strictures should be cautiously dilated with Hegar dilators or an endoscopic balloon, as perforation is a risk. The stricture may be primary or occur as a complication of anorectal or ileal pouch surgery performed on the basis of an incorrect preoperative diagnosis of ulcerative colitis or indeterminate colitis. Severe strictures that do not respond to dilation may require an advancement flap (in low anal strictures) or ultimately fecal diversion or proctectomy (in anorectal stenosis).

Given the unpredictable disease process of perianal Crohn fistulas and the variety of surgical options, management should be individually tailored, using combined medical and surgical approaches to offer the patient an improved quality of life.