CHAPTER 113 Ileostomy, Colostomy, and Pouches
Proctocolectomy and permanent ileostomy return most patients with chronic ulcerative colitis (UC) to excellent health and remove premalignant mucosa in patients with UC or familial adenomatous polyposis (FAP). Many of the inconveniences and dangers formerly associated with an ileal stoma have been eliminated by improved surgical techniques, a wider range of better stomal appliances, and more effective education of patients.1
Between 1930 and 1950, the metabolic consequences of ileostomy became apparent, as did the frequent mechanical complications caused by ileostomy dysfunction. Better understanding of fluid, electrolyte, and blood replacement lessened the former problem, and newer techniques of ileostomy construction mitigated the second.2,3 Before these advances, ileostomies were made by withdrawal of the intestine through the abdominal wall, the serosal surface of ileum then being sutured to the skin. Ileostomy dysfunction resulted from the serositis following exposure of the serosal surface to the stomal effluent. The mucosa of the ileum, however, is not susceptible to inflammation after a similar exposure, and a solution, therefore, became conceptually simple: evert the mucosal surface of the bud and suture the mucosa to the skin. This modification was described simultaneously early in the 1950s in the United Kingdom and United States and is commonly referred to as a Brooke ileostomy (Fig. 113-1).1 Development of new ileostomy appliances quickly led to better acceptance by patients and, ultimately, to excellent long-term results.4 Enterostomal therapy was introduced in the 1960s as an additional allied health support, and ileostomy societies have blossomed in most countries, providing a lay component of support to patients with stomas.
Brooke ileostomies are incontinent by definition, and during the 1960s, Nils Kock, a Swedish surgeon, developed the first effective alternative to this incontinent ileostomy.5 The Kock pouch procedure featured an ileal pouch, a nipple valve, and an ileal conduit, which led to a cutaneous stoma that, because this ileostomy was continent and therefore an appliance was not needed, could be made flush with the skin. The Kock pouch was used in selected patients with chronic UC and FAP.6
Stimulated by patients’ poor acceptance of the ileostomy, surgeons explored other alternatives to the incontinent ileal stoma with its ever-present external appliance. The ileoanal pull-through operation was resurrected, with an important technical modification: the addition of an ileal reservoir.7,8 This procedure offered the advantages of a normal exit for stool and preservation of the anal sphincters. Indeed, the use of this procedure in thousands of patients has revealed ileal pouch-anal anastomosis (IPAA) to be the procedure of choice in most patients requiring proctocolectomy for chronic UC or FAP.
PATHOPHYSIOLOGIC CONSEQUENCES OF PROCTOCOLECTOMY
FECAL OUTPUT AFTER PROCTOCOLECTOMY
After a colectomy with any type of ileostomy, the absence of the colon obviously prevents its reabsorption of electrolytes and water. Usually, this creates no major pathophysiologic disturbance, but some important principles should be remembered. A normal colon absorbs at least 1000 mL of water and 100 mEq of sodium chloride each day, and the healthy colon can increase absorption more than 5 L/day when presented with increased amounts of fluid.9,10
Also, the colon has a greater capacity than the small intestine to conserve sodium chloride when a person is salt depleted. For example, under conditions of extremely low salt intake, sodium losses in normal stool can be reduced to 1 or 2 mEq/day, whereas patients with ileostomies have obligatory sodium losses of 30 to 40 mEq/day.11–13 The majority of patients adapt to these daily losses through minor changes in salt and water intake and physiologic compensation.14
Well-functioning conventional (Brooke) ileostomies discharge 300 to 800 g of material daily, 90% of which is water.12,13 Continent ileostomies and IPAAs have similar volumes of effluent.15 Foods containing substantial unabsorbable residue increase the total ileostomy output by increasing the amount of solids discharged. Although many anecdotes are reported on the effect of foods on the volume and consistency of stomal effluents, the response to specific foods varies from one patient to another, and changes usually are minimal.16
FUNCTIONAL SEQUELAE
When oral intakes of sodium, chloride, and fluid are adequate, patients with ileostomies do not become depleted in volume or electrolytes; negative sodium balance, however, can follow periods of diminished oral intake, vomiting, or excess perspiration.17 In addition, chronic oliguria is to be anticipated, even with established ileostomies, because normal stools contain approximately 100 mL of water, whereas ileostomies lose 500 to 600 mL/day.14 Patients with ileostomies also have lower urinary Na+/K+ ratios because of compensatory renal conservation of sodium and water. These changes in the composition of urine presumably contribute to the increased frequency of urolithiasis (about 5%) in patients with ileostomies, whose stones are predominantly composed of urate or calcium salts18; these patients have relatively narrow tolerances for change in their volume and electrolyte status, and even minor changes potentially result in life-threatening electrolyte disturbances.19
When the terminal ileum is resected and a proximal ileostomy is constructed, there can be abnormalities of bile acid reabsorption, malabsorption of vitamin B12 (see Chapters 64, 100, and 101), steatorrhea, and more than expected losses of fluid (1 L/day). These abnormalities usually do not follow a colectomy that is performed for chronic UC or FAP because the ileum, being free of disease, is preserved. Resection for Crohn’s colitis can require removal of additional diseased ileum with the possible consequences of malabsorption and even short bowl syndrome, depending on the length of small bowel removed (see Chapters 101, 103, and 111).
Colectomy also reduces the exposure of bile acids to the metabolic effects of the fecal flora, and after ileostomy, secondary bile acids largely disappear from bile; no metabolic consequences of significance have been recognized in this situation.20,21 The flora of ileostomy effluents have quantitative (104 to 107 colony-forming units [CFUs] per 100 milliliters) and qualitative characteristics that are intermediate between those of feces and those of normal ileal contents, whereas the flora in an IPAA or Kock pouch are more similar to feces.22–24
The principal pathophysiologic sequelae of colectomy with ileostomy are mainly the potential consequences of a salt-losing state; patients should be advised to use salt liberally and to increase their fluid intake, especially at times of stress, in hot weather, and after vigorous exercise. A balanced salt solution (Gatorade or Powerade) is a good source of balanced electrolytes. The limited ability of the small intestine to absorb sodium and water, however, means that stomal volumes also increase when the oral intake is increased.13
CLINICAL CONSEQUENCES OF PROCTOCOLECTOMY
After successful proctocolectomy, life expectancy is slightly below normal for the first few years owing to complications of the stoma and to intestinal obstruction; after ileorectostomy for FAP or chronic UC, particularly the former, cancer can develop in the retained rectum. In general, however, the long-term mortality rate in patients after proctocolectomy and conventional ileostomy is the same as for a matched normal population.25 Ninety percent of patients with conventional ileostomies who responded to a survey rated the results of their operation excellent and claimed little inconvenience.4 Overall, there is no real difference in the reported quality of life of patients with conventional ileostomies, continent ileostomies, or an ileal pouch.26 Almost all were able to lead normal lives and enjoy normal sexual relationships; a few patients avoided certain strenuous physical activities.
The metabolic consequences of a proctocolectomy per se should be the same regardless of whether a conventional ileostomy or an alternative procedure is performed. Patients in whom an ileostomy alternative achieves an excellent result have a better quality of life than do patients with a stoma because the former do not need to wear an ileostomy appliance. Indeed, when the Brooke ileostomy and IPAA were compared, patients with IPAA experienced significant advantages in performing daily activities and appeared to enjoy a better quality of life.27 There are certain unique complications of the newer operations, however, including incontinence (Kock pouch), pelvic infections and sepsis, and pouchitis (IPAA), which are discussed later.
THE CONVENTIONAL BROOKE ILEOSTOMY
Prestomal ileitis is a much less common problem than is stomal obstruction. Patients with this complication exhibit the features of mechanical obstruction, and, in addition, they have signs of systemic toxicity (e.g., fever, tachycardia, anemia).28,29 In prestomal ileitis, the ileum has numerous punched-out ulcers, sometimes extending to the serosa. It is not clear whether prestomal ileitis has a different pathogenesis from the changes that follow simple mechanical obstruction of the stoma; both complications involve ileum that was normal histologically at the time of colectomy. Backwash ileitis, seen typically in chronic UC, does not predispose to either prestomal ileitis or obstruction. Conversely, patients who have had colectomy and ileostomy for Crohn’s disease experience problems with the ileal stoma more often, perhaps because transmural inflammation involves the new terminal ileum. In some instances, it is difficult to determine whether stomal dysfunction results from mechanical obstruction or recurrent Crohn’s disease.
Most people with an ileostomy lead a normal life and eat a normal diet; poorly digestible foods (e.g., nuts, corn, some fruits, lightly cooked vegetables) can obstruct the stoma and should be eaten in moderation and with careful chewing.4 Some patients experience continuing difficulties managing their ileostomy. These problems vary in severity, some being minor inconveniences and others being significant drawbacks to the success of the operation. Mechanical difficulties because of a poorly fitting stomal appliance can cause excoriation of the skin around the ileostomy and can even erode the stoma to produce a fistula. Some patients complain of unpleasant odors arising from the ileostomy bag, especially after eating certain foods, such as onions and beans. Because most odor arises from bacterial action on the contents of the appliance, however, the problem may be offset by frequent emptying of the appliance or by adding sodium benzoate or chlorine tablets to the appliance. Oral bismuth subgallate also controls odor, but doubts exist as to whether its long-term use is justified, because questions of neurotoxicity and encephalopathy have been raised.30,31
A review of the long-term outcomes associated with ostomies has demonstrated a high rate of complications. The most common problems related to ostomies are skin irritation and parastomal hernias, both of which contribute to difficulty with appliance pouching, a term used by enterostomal therapists and referring to the fitting of an ostomy device. Several risk factors are associated with development of parastomal hernias, including obesity, malnutrition, chronic respiratory disorders that are associated with increased intra-abdominal pressure, chronic use of glucocorticoids or other immunosuppressive agents, malignancy, advanced age, and wound infection.32–35 Several techniques have been described for parastomal hernia repair, including primary fascial repair, stoma relocation, and mesh repair; mesh repair achieves the best outcomes.32 The simplest approach, primary repair, is associated with very poor outcomes and up to 100% recurrence rates. Stoma relocation may be an effective approach when the initial stoma site is unsatisfactory, but parastomal hernias occur at the new site in up to 76% of patients.35 The use of prosthetic mesh for parastomal hernia repair has significantly improved outcomes, with recurrence rates reported as low as 10%.36,37 To address the concerns of possible mesh infection and erosion of mesh into the bowel, the use of biologic materials, such as human acellular dermal matrix, has been reported, with results that are comparable to mesh in small series.38
Trained stomal therapists and lay societies of ileostomy patients can help with numerous aspects of postoperative care. Education of the patient is best started before surgery; meetings with others who have undergone ileostomy and referral to specialized publications can allay many fears and uncertainties. The United Ostomy Associations of America (UOAA, P.O. Box 66, Fairview, TN 37062-0066; www.uoaa.org) publishes an excellent series of booklets dealing with all aspects of life for the ostomy patient. These materials also are of great help to patients and nursing staffs in the absence of a registered enterostomal therapist (wound ostomy and continence nurse [WOCN]). The location of a registered therapist can be obtained from the Wound Ostomy and Continence Nurses Society (WOCN Society National Office, 15000 Commerce Parkway, Suite C, Mt. Laurel, NJ 08054; www.wocn.org).
CONTINENT ILEOSTOMY (KOCK POUCH)
Clearly, one of the major (social) drawbacks to ileostomy could be eliminated if a continent stoma were possible. Nils Kock reasoned that a pouch and nipple valve constructed of terminal ileum could store ileal content internally until emptied voluntarily by the patient passing a large, soft catheter into the pouch several times daily, thereby obviating the need for an external appliance (Fig. 113-2). The first such operations were reported in 1969, and the results were promising; however, the nipple valve sometimes failed, usually because it slipped out of the pouch, resulting in incontinence.5 Techniques gradually improved, and the most recent approaches have been more successful, providing continence in most patients. In two series, more than 90% of patients were continent for gas and feces (i.e., never requiring an appliance).34,39
This high success rate, however, is achieved at the price of additional operations in most patients for nipple or pouch dysfunction, fistula, or stricture. Wasmuth and colleagues reported a 50% rate of reoperation by 14 years after continent ileostomy construction.40 Furthermore, in a series reported by Lepisto, 59% of patients with a continent ileostomy required reoperation, with a total of 85 pouch reconstructions being performed: 42 patients had one reconstruction, nine had two reconstructions, three had three reconstructions, one had four reconstructions, and two had six reconstructions.41 Others have reported similar findings: patients generally did well after initial continent ileostomy construction, but a sizable minority required repeated surgical intervention either to salvage pouch function or remove the pouch.42,43
Despite requiring numerous reoperations, the majority of Kock pouch patients are satisfied with the outcomes of their functioning pouch. In a recent comparative study on quality of life in patients with standard ileostomies, ileal pouch, and Kock pouch, the Kock pouch patients did not fare significantly better or worse than those with a conventional ileostomy or IPAA; 56% of the continent ileostomy patients, however, did require reoperation to maintain function of the continent ileostomy.26
The fundamental mechanical problem of the nipple valve design in the Kock pouch has prevented widespread acceptance of the procedure. Another continent ileostomy, the T pouch, has been developed to combat this problem44; its design prevents slippage of the intussusceptive nipple valve constructed in the traditional Kock pouch. In the T pouch, the valve mechanism is made by securing an isolated distal ileal segment into a serosal-lined trough formed by the base of two adjacent ileal segments. The high volume-low pressure reservoir is fashioned around this isolated valve segment. Once constructed, the distal end of the valve mechanism is brought up through the skin as a stoma. T pouches have been constructed in only a few patients, and the results are promising, but long-term follow-up is required to assess the structural integrity and clinical success of the new valve design. Given the wide acceptance of the IPAA, continent ileostomy operations are performed rarely and used mainly in patients who have had a proctocolectomy and ileostomy and who desire enteric continence.
ILEAL POUCH-ANAL ANASTOMOSIS
IPAA is now the procedure of choice for most patients who require proctocolectomy for chronic UC or FAP. IPAA is not considered suitable for patients with Crohn’s disease, although this recommendation now is being questioned.45,46 The operation has several major advantages: nearly all mucosal disease is removed in contrast to ileorectostomy; the normal route for elimination is maintained (a permanent stoma is not required); the anal sphincters are undisturbed; and the pelvic dissection, being less extensive than in cancer operations, should not endanger innervation of the sexual organs.
The general principle of ileoanal anastomosis was first described in 1947, and its revival was influenced by the success of pediatric surgeons in children with Hirschsprung’s disease.7 Early approaches used a straight pull-through and sutured the ileum directly to the anal verge.47 Although results in children were encouraging, excessive stool frequency and anal seepage were unacceptable to many adult patients. Subsequently, the operation was modified to include one of several forms of ileal pouch. The basic surgical steps are as follows: a proctocolectomy is performed; the distal rectal mucosa is divided at the top of the anal canal, which leaves a small cuff of residual rectal and anal canal mucosa; an ileal pouch is fashioned and then stapled or sutured to the cuff of remaining rectal and anal canal tissue. A diverting ileostomy is usually required for two to three months until the anastomosis heals completely. At a second operation eight to 12 weeks later, the diverting ileostomy is closed.
The Mayo Clinic has acquired considerable experience with IPAA, having performed more than 2200 of these operations.48–50 Although pouches of different configurations have been advocated by various surgical groups in the past, the pouch routinely used today is the J pouch because of its ease of construction and reliable function (Fig. 113-3).
LONG-TERM RESULTS
IPAA is a complex operation and complications occur frequently. The overall morbidity rate still hovers between 25% and 30%.49–51 Failure, however, is rare, even in those who suffer a postoperative complication.
At the Mayo Clinic, overall pouch success rate was 92% in patients who had had their IPAA for up to 20 years.52 In this series of 1885 IPAA operations performed for UC over a 20-year period with a mean follow-up of 11 years, the overall rate of pouch success at 5, 10, 15 and 20 years was 96.3%, 93.3%, 92.4% and 92.1%, respectively. Over time, the mean daytime stool frequency increased from 5.7 times at one year to 6.4 times at 20 years; nighttime stool frequency also increased from 1.5 to 2.0. The incidence of frequent daytime fecal incontinence increased from 5% to 11% during the day (P < 0.001) and from 12% to 21% at night (P < 0.001). This series demonstrated that IPAA is a reliable surgical procedure for patients requiring proctocolectomy for UC and indeterminate colitis. Furthermore, it showed that the clinical and functional outcomes are excellent and durable.
Complications
Pelvic sepsis, an ominous development, occurs in 5% to 24% of patients after IPAA.49,50,53,54 Computed tomography (CT) is useful for demonstrating pelvic fluid collections or phlegmon. Patients with pelvic phlegmon usually respond to conservative treatment with broad-spectrum antibiotics and bowel rest, whereas patients with a pelvic abscess ideally should undergo CT-guided drainage, if technically feasible, or laparotomy and drainage (Fig. 113-4). The most commonly cited risk factor for pelvic sepsis is chronic or high-dose glucocorticoid use in the perioperative period.55 Pelvic sepsis can, in the short-term, lead to pouch excision, which fortunately is rare; long-term functional results of the pouch are worse, however, and there is a higher rate of pouch loss compared with patients who did not experience pelvic sepsis.52
A diverting temporary ileostomy, while minimizing the impact of pelvic sepsis, is associated with a number of complications.56 Closure of temporary ileostomies also may be associated with complications. Peritonitis occurred in 4% of patients and postoperative intestinal obstruction in 12% of patients. Proximal and distal serosal tears during stoma mobilization, in addition to anastomotic leaks, are important causes of peritonitis. If all extraperitoneal bowel (afferent and efferent limbs and the stoma itself) is resected, however, the chance of leaving an unrecognized perforation is nearly eliminated.
Almost all patients have a web-like stricture of the ileoanal anastomosis before ileostomy closure (Fig. 113-5). This stricture generally can be dilated digitally without difficulty, but narrowing can recur and is the most common indication for surgical intervention after an IPAA.57 If the pouch retracts under anastomotic tension, heavy scarring can result in a long, fibrotic stricture. This type of stricture is manifested by increased straining to empty the pouch, a sensation of incomplete pouch evacuation, or a high stool frequency (more than 10 to 12 stools per day). Repeated anal dilation can prevent progression of the stricture.
Clinical Results
Following an IPAA, the average stool frequency is six stools during the day, with one stool at night.48–5054 Daytime and nocturnal stool frequency and the ability to discriminate flatus from stool remain relatively stable over time, whereas the need for stool bulking and hypomotility agents declines. The lower stool frequencies six months after surgery compared with the frequency in the early postoperative period are likely attributable to increased pouch capacity over time.
In the Mayo Clinic experience, major fecal incontinence (more than twice per week) occurs in 5% or less of patients during the day and 12% of patients during sleep.50 In contrast, minor episodes of nocturnal incontinence occur in up to 30% of patients at least one year after the operation. A pad must be worn by 28% of patients for protection against seepage. Minor perianal skin irritation is reported by 63% of patients. Patients older than 50 years have a higher daytime stool frequency (eight per day) than do patients younger than 50 years (six per day). Men and women have similar stool frequencies postoperatively, but women have more episodes of fecal soilage during the day and night; this is thought to be related to a shorter average anal canal length in women. Seventy-eight percent of patients report excellent continence one year after surgery, which remains unchanged at 10 years; 20% experience minor incontinence; and 2% have poor control. Of patients with minor incontinence at one year, 40% remain unchanged, 40% improve, and 20% worsen by 10 years.52 Nocturnal fecal spotting increases during the 10-year period, but not significantly.
Pouchitis and Cuffitis
A wide range of reported incidences suggests that the level of clinical suspicion and the diagnostic criteria for pouchitis vary greatly.58–60 An early experience in IPAA patients demonstrated that patients who have preoperative extraintestinal manifestations of UC had significantly higher rates of pouchitis than patients without such manifestations (39% with preoperative symptoms and 26% without).58 A recent study by Hoda and colleagues, however, demonstrated that whereas extraintestinal manifestations might indicate a predisposition to episodes of acute pouchitis, they are not predictors of chronic pouchitis.60 Furthermore, they report that patients at highest risk for developing chronic pouchitis suffered from postoperative complications, more specifically anastomotic and septic complications.
Other investigators have suggested that there is a biological predisposition for pouchitis and that better risk stratification can be obtained by the preoperative use of serum markers of IBD.61–63
