Crohn's Disease of the Duodenum
Primary Crohn's disease of the duodenum almost always manifests with stricturing disease that can be managed by strictureplasty or with bypass procedures (Fig. 33-16). Fortunately, resection of the duodenum for Crohn's disease is almost never required.161–163 Perforating Crohn's disease almost never affects the duodenum. When the duodenum is involved with Crohn's fistulas, it is always the result of disease within a distal segment (typically the terminal ileum or neoterminal ileum) that fistulizes into an otherwise normal duodenum.164 Yet, Crohn's disease of the duodenum can offer a particularly challenging problem due to the retroperitoneal location of the organ and its intimate proximity with the pancreas.
Upper GI study demonstrating Crohn's strictures of the duodenum. Contrast seen within the biliary ducts is due to deformity and incompetence of the ampullary sphincter secondary to the Crohn's disease. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
Stricturing disease of the duodenum is often focal and many cases can be managed with a strictureplasty.165 In order to safely accomplish a strictureplasty, the duodenum must be fully mobilized with a generous Kocher maneuver. Heinecke-Mikulicz strictureplasties can be safely performed in the first, second, and proximal third portion of the duodenum. Strictures of the last portion of the duodenum are better handled with a Finney strictureplasty constructed by creating an enteroenterostomy between the fourth portion of the duodenum and the first loop of the jejunum.
If the duodenal stricture is lengthy or the tissues around the stricture are too rigid or unyielding, a strictureplasty should not be performed and an intestinal bypass procedure should be undertaken. The most common bypass procedure performed for duodenal Crohn's disease is a simple side-to-side retrocolic gastrojejunostomy.121 This procedure effectively relieves the symptoms of duodenal obstruction related to Crohn's strictures but carries a high risk for stomal ulcerations. To lessen the likelihood of ulcerations forming at the anastomosis, it has been recommended that a vagotomy be performed along with the gastrojejunostomy.121 Because of the concerns of vagotomy-related diarrhea, a highly selective vagotomy is preferred to a truncal vagotomy. If the stricturing Crohn's disease is limited to the third or fourth portions of the duodenum, a Roux-en-Y duodenojejunostomy to the proximal duodenum is preferred to a gastrojejunostomy.164 The Roux-en-Y duodenojejunostomy has the advantage of bypassing strictures and eliminates the concern regarding acid-induced marginal ulceration and the need for vagotomy.
As noted previously, when the duodenum is involved with a Crohn's fistula, it is almost always the case that the diseased segment is located distal in the GI tract and the duodenum itself is otherwise free of active Crohn's disease.164 Most of these duodenal fistulas are small in caliber and asymptomatic, but larger fistulas may shunt the duodenal contents to the distal small bowel such that malabsorption and diarrhea result. In the majority of cases, duodenoenteric fistulas are identified with preoperative small bowel radiography; however, many are discovered only at the time of surgery.166 With complex fistulizing disease involving an inflammatory mass, great care at the time of surgery should be undertaken to limit the size of the duodenal defect resulting from the resection of the fistula. Most duodenal fistulas are located away from the pancreaticoduodenal margin, and thus these fistulas can be managed by resection of the primary Crohn's disease with primary closure of the duodenal defect. Larger fistulas or fistulas that are involved with a large degree of inflammation may result in a sizable duodenal defect. Such large defects may require closure with a Roux-en-Y duodenojejunostomy or with a jejunal serosal patch.166,167 As noted previously, duodenal resections are almost never necessary for Crohn's disease and they should be considered the surgical option of last resort.
Crohn's Disease of the Small Bowel
Complete Intestinal Obstruction
Complete small intestinal obstruction resulting from Crohn's disease only rarely requires urgent surgical intervention, as the vascular supply to the intestinal loop is never compromised and almost all cases of complete or high-grade partial small bowel obstruction from Crohn's disease respond to conservative management. Such patients should be treated with nasogastric decompression, intravenous hydration, and steroid therapy.121 This program allows for resolution of the acute episode of obstruction in a vast majority of cases. Unfortunately, most patients whose Crohn's disease is severe enough to experience an episode of complete or high-grade partial obstruction are at high risk for recurrent episodes and persistent symptoms. For this reason, elective surgery should be considered once the episode of complete obstruction has resolved. The advantage of this approach is that surgery can be performed under safer conditions when the obstruction has resolved, the bowel is not distended or edematous, and an appropriate bowel preparation has been performed. If the obstruction fails to respond to appropriate conservative treatment, surgery is required. In these situations, the surgeon needs to have a high index of suspicion for small bowel cancer as the cause of the obstruction, as obstructions from cancers do not respond to bowel decompression and steroid treatment.
Ileosigmoid fistula is a common complication of perforating Crohn's disease of the terminal ileum. Typically, the inflamed terminal ileum adheres to the sigmoid colon that is otherwise normal and free of primary involvement of Crohn's disease. Most ileosigmoid fistulas are small and do not produce any symptoms. Asymptomatic ileosigmoid fistulas do not in and of themselves require operative management. On the other hand, large ileosigmoid fistulas can result in bypass of the intestinal contents from the terminal ileum to the distal colon and thus give rise to debilitating diarrhea (Fig. 33-17). Such symptomatic fistulas often fail to respond to medical therapy and should be managed surgically.
Contrast enema demonstrating large ileosigmoid fistula. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
More than half of the ileosigmoid fistulas from Crohn's disease are not recognized prior to surgery.168 For this reason, the surgeon should be prepared to deal with this complication in any case of Crohn's disease that involves the terminal ileum. Ileosigmoid fistulas can be managed by simple division of the fistulous adhesion and resection of the ileal disease. The defect in the sigmoid colon is then débrided and simple closure is undertaken. In this manner, 75% of ileosigmoid fistulas can be managed.55,168 The remainder require resection of the sigmoid colon. Sigmoid colon resection is necessary when primary closure of the fistula is at risk for poor healing. This is the case either when the sigmoid is also involved in Crohn's disease when the fistulous opening is particularly large, or when there is extensive fibrosis extending along the sigmoid colon. Also, fistulous tracts that enter the sigmoid colon in proximity to the mesentery can be difficult to close and often require resection and primary anastomosis.
Ileovesical fistulas occur in approximately 5% of Crohn's disease patients.93 Hematuria and fecaluria are virtually diagnostic of ileovesical fistula, but these symptoms are absent in one-third of cases.169 Small bowel x-rays, cystograms, and cystoscopy often do not detect the fistula. Air within the bladder, as noted on CT scan, is often the best indirect evidence for the presence of an enterovesical fistula. An ileovesical fistula is an indicator of complex fistulizing disease, as most ileovesical fistulas occur along with other enteric fistulas. For example, as many as 60% of patients with an ileovesical fistula will also have an ileosigmoid fistula.55
The necessity for surgery for ileovesical fistula is controversial. Many patients with ileovesical fistulas can be managed medically for extended periods of time without significant complications. Healing rates with medical treatment are not clearly defined, but they are probably low and most patients with ileovesical fistulas will ultimately come to surgery. Surgery is indicated when recurring urinary infections occur, particularly pyelonephritis, with concomitant potential for worsening of renal function.
Surgical treatment of ileovesical fistulas requires resection of the ileal disease with closure of the bladder defect. Most ileovesical fistulas involve the dome of the bladder, and thus débridement and primary closure can be accomplished without risk of injury to the trigone. Decompression of the bladder with an indwelling Foley catheter should be continued postoperatively until the bladder is confidently healed without leaks. A cystogram taken on postoperative day 5 is a convenient means for confirming the seal of the bladder repair and the safety of removing the Foley catheter.
Enterovaginal and Enterocutaneous Fistulas
These are rare fistulas caused by perforating small bowel disease draining through the vaginal stump in a female who has previously undergone a hysterectomy or through the abdominal wall, usually at the site of a previous scar. These fistulas often require surgical intervention because they cause physical discomfort and personal embarrassment. Surgical treatment requires resection of the small bowel disease. The vaginal cuff does not need to be closed; the chronic infection along the abdominal wall fistulous tract requires debridement and wide drainage to allow healing by secondary intention.
Intra-abdominal abscesses that result from Crohn's disease tend to follow an indolent course with modest fever, abdominal pain, and leukocytosis. Rapidly progressive and overwhelming sepsis is not typical for the clinical course of Crohn's disease–related abscesses. In fact, in up to one-third of intra-abdominal Crohn's abscesses preoperative clinical signs of localized infection are absent and the abscesses are discovered only at the time of operation. When an abscess is suspected or an abdominal mass is palpated, a CT scan should be obtained, as 50% of tender intra-abdominal masses will harbor an abscess collection within.100 The CT scan can detect most chronic abscesses and can also delineate the size and location of the abscess as well as the relationship of the abscess to critical structures such as the ureters, duodenum, and the inferior vena cava (Fig. 33-18).
CT scan of the pelvis demonstrating large Crohn's abscess. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
Most abscesses with Crohn's disease are in fact very small collections that are contained within the area of diseased intestine and its mesentery. In the case of small intraloop or intramesenteric abscesses, resection of the defective segment and its mesentery often extirpates the abscess such that drains are not necessary and primary anastomosis can be performed without risk.
Large abscesses related to Crohn's disease are best managed with CT-guided percutaneous drainage.102 Percutaneous drainage is often very effective at controlling the sepsis and healing the abscess cavity.101 With percutaneous drainage of a Crohn's disease abscess, an enterocutaneous fistula often occurs as the abscess typically connects to a deeply penetrating sinus emanating from a segment of Crohn's disease–affected intestine. Percutaneous drainage then completes the fistulous tract from the intestine through the sinus to the abscess cavity and out the drain. Such a fistula may spontaneously close or it may persist, and the intestine may continue to be a source of sepsis. With successful drainage of the abscess, the sepsis often clears well enough that it can be tempting to try to manage the disease without subsequent surgery. Published clinical data on the optimal approach to such patients are unfortunately lacking. Even so, in the absence of Crohn's symptoms, initial nonoperative management after successful percutaneous drainage can be undertaken in carefully selected patients.103 On the other hand, if drainage through the fistula continues, surgical resection of the affected segment of intestine becomes necessary.
Free perforation is a surprisingly uncommon phenomenon because the chronic progressive inflammation of Crohn's disease normally leads to adhesions with adjacent structures. Most perforations from Crohn's disease occur in the ileum and are usually proximal to a stenotic lesion.104,121 The diagnosis of free perforation is made by detecting a sudden change in the patient's symptoms along with the development of the physical findings of peritonitis or the identification of free intraperitoneal air as demonstrated on plain x-rays or CT scans. Free perforation is an absolute indication for emergent laparotomy with resection of the diseased segment and exteriorization of the proximal bowel as an end ileostomy. The distal bowel end can be exteriorized as a mucous fistula or closed as a defunctionalized pouch, depending on the degree of peritoneal contamination. Creation of a primary anastomosis even with a proximal protecting loop ileostomy carries a high risk of anastomotic breakdown and should be avoided. Primary closure of the perforation should never be attempted, as sutures will not be able to approximate the edges of the perforated, edematous, and diseased bowel in a satisfactory and tension-free way and the presence of a distal intestinal stenosis or partial obstruction will cause an increase in the intraluminal pressure at the level of the local repair with subsequent dehiscence.
Hemorrhage from small bowel Crohn's disease is managed by resection of the diseased portion of intestine. For patients with multiple skip areas of Crohn's disease, small bowel angiography may be attempted to localize the exact site of bleeding.105 Localization with angiography may be unsuccessful if the bleeding is episodic or insufficiently brisk to be identified with angiography. In patients in whom small bowel hemorrhage stops spontaneously, the risk for rebleeding is high. Thus elective resection of active Crohn's disease after the first episode of hemorrhage should be considered.
Crohn's Disease of the Colon
The optimal management of Crohn's disease of the colon is dependent on the distribution and the location of the disease (Fig. 33-19).
Contrast enema demonstrating severe Crohn's colitis with multiple high-grade strictures. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
Colonic disease limited to the cecum is almost always associated with terminal ileal disease. The terminal ileitis is the predominant component of the ileocecal disease. Terminal ileal disease with extension into the cecum behaves much like disease limited to the terminal ileum. For this pattern of disease, surgical resection should encompass the margins of gross disease with an anastomosis between the neoterminal ileum and the proximal ascending colon. Recurrence of disease at the anastomosis or at the preanastomotic ileum is common, but the risk for recurrent disease within the distal colon or the rectum is low. This pattern of disease does not imply a predisposition to more extensive colonic disease.
Disease involving the entire right colon can occur alone but more typically occurs along with disease of the terminal ileum. Extensive involvement of the right colon as a form of ileocolonic disease is less common than the ileocecal pattern. Surgical treatment involves a standard right hemicolectomy to encompass the gross limits of the disease. An anastomosis between the ileum and the transverse colon is then fashioned. With a standard right hemicolectomy, the anastomosis may rest in proximity to the duodenum. Recurrent disease at the preanastomotic ileum may thus secondarily involve the duodenum. This phenomenon can place the patient at risk for substantial morbidity should inflammatory encasement of the duodenum or fistulization into the duodenum occur. For this reason it is advantageous to protect the duodenum by interposing omentum between the duodenum and the ileocolonic anastomosis.
Extensive Colitis with Rectal Sparing
Extensive colitis with sparing of the rectum occurs in approximately 20% of individuals suffering from Crohn's colitis. In such cases, the rectum should be closely examined endoscopically, and, should the rectum be truly free of disease, a total abdominal colectomy with ileorectal anastomosis can be performed when fecal continence is adequate and the patient does not have extensive perineal septic complications. This procedure often results in good long-term function and enables many patients to avoid an ileostomy. Older patients or patients who have undergone an extensive small bowel resection may experience frequent and loose stools to the point that incontinence may develop after an ileorectal anastomosis. Additionally, recurrent disease within the rectum can result in significant deterioration of bowel function requiring further medical or even surgical intervention. Up to 50% of patients who undergo an ileorectal anastomosis for colonic Crohn's disease will ultimately require a proctectomy with permanent ileostomy because of poor bowel function with incontinence or recurrence of disease in the rectum.170
Surgical management of extensive involvement of the colon and rectum requires total proctocolectomy with permanent ileostomy in almost all cases. In most instances, a total proctocolectomy can be performed in a single step. The presence of severe perianal disease, however, may require that the procedure be performed in two stages. At the first stage, the intra-abdominal colon and majority of the rectum are removed and a short rectal stump is created at the level of the levator muscles. At the same time, perineal abscesses are drained and fistulas are laid open. This first step removes the diseased colon and rectum without creating a perineal wound that may be difficult to heal in the presence of active perineal sepsis. Once the perineal sepsis is cleared and the perineum is healed, the short anorectal stump can be removed through a perineal approach. At the second stage, primary closure of the perineum can be accomplished without the high risk of persistent perineal wounds.
Restorative procedures such as an ileal pouch–anal anastomosis or continent ileostomy have traditionally not been offered to patients who have Crohn's colitis because of the recurrent nature of the disease. Even so, some of these procedures have been performed in patients whose diagnosis of Crohn's disease was not known or suspected at the time of surgery. Various reports indicate that recurrence of Crohn's disease within the pouch is common and removal of the pouch is often necessary. On the other hand, those patients who do not suffer from recurrent disease generally do well and typically experience good pouch function.
While it is commonly accepted that restorative proctocolectomy with J-pouch ileoanal anastomosis should not be undertaken for Crohn's colitis, there is a specific pattern of Crohn's disease that appears to be at low risk for problems with recurrence after an ileoanal anastomosis.171,172 In cases in whom Crohn's disease is limited to the colon and rectum without any history of small bowel involvement and without any perineal manifestations, the risk for pouch failure after ileoanal anastomosis appears to be low and such patients can be considered for the ileoanal procedure. This particular pattern of Crohn's disease, however, is rare, as most patients with Crohn's proctocolitis will have some degree of small bowel involvement or perineal manifestations and thus would not be considered candidates for the ileoanal procedure.
Crohn's inflammation limited to the rectum is unusual. Surgical management of Crohn's proctitis mandates proctectomy with permanent stoma. The need for resection of the normal proximal colon is controversial. Abdominoperineal resection with end sigmoid colostomy has been associated in some reports with a high risk for stomal complications and recurrent disease in the proximal intestine when compared to total proctocolectomy with end ileostomy. For these reasons, total proctocolectomy with ileostomy has been recommended for Crohn's disease limited to the rectum and distal colon. This more extensive resection may be of greater value in younger patients who have no history of small bowel Crohn's disease, as it appears that colorectal Crohn's disease without small bowel involvement is unlikely to result in recurrence within the small bowel once a proctocolectomy is performed.40 If the patient has undergone a prior resection for small bowel Crohn's disease, they may be at risk for high output from the ileostomy and therefore may benefit from the preservation of colonic absorptive capacity. Preservation of the colonic absorptive capacity may be beneficial also in the elderly patient. Thus these patients may be better managed with a proctectomy and end sigmoid colostomy.
Proctectomy for Crohn's disease does not require a wide excision of perirectal tissue. To avoid injury to pelvic sympathetic and parasympathetic nerves, the dissection should be undertaken close to the rectal wall. This is sometimes challenging in the presence of severe rectal mesenteric inflammatory reaction. In the absence of significant perianal disease, the perineal dissection is best carried out along the plane between the internal and external sphincters.173 This intersphincteric dissection allows for a perineal closure that is associated with fewer complications and better healing than wider dissections that encompass the entire sphincter mechanism. In some patients, fistula from the perianal Crohn's disease can traverse the intersphincteric plane and a wider dissection is required in order to encompass the diseased tissue. In the presence of significant perianal disease, a staged approach, as described previously, can be utilized as an option. Occasionally, however, because of extensive rectal disease, closure of the rectal stump may be technically challenging or not feasible, forcing the surgeon to proceed with a proctectomy in the face of perianal sepsis. These dissections may need to be carried out widely and extensive loss of perianal skin and subcutaneous tissue may occur. The resultant defects are often too large for primary closure, and closure may require advanced tissue transfer techniques such as gluteal flaps, gracilis flaps, or myocutaneous rectus abdominis pedicle flaps. These closures may have to be staged as well in the presence of perineal sepsis. Large open perineal wounds may be managed temporarily or definitively with the assistance of the vacuum-assisted closure device. This device allows for rapid contracture of the wound and facilitates healing.
The optimal management of segmental colitis is dependent primarily on the location of the disease and secondarily on the presence and severity of concurrent perineal complications, the degree of fecal continence, and the natural history of the disease in the residual colon. Segmental involvement of the right colon should be managed by simple right hemicolectomy with ileotransverse anastomosis. For segmental disease involving the transverse colon, an extended right hemicolectomy is generally preferred to a segmental transverse colectomy. Such an approach may have a lower risk of recurrence compared to a segmental resection of the transverse colon. Additionally, the extended right hemicolectomy avoids a colocolonic anastomosis that is associated with a higher risk for anastomotic dehiscences and strictures.
For disease in the descending or sigmoid colon, the appropriate surgery is more controversial. Presence and severity of concurrent perineal complications, the degree of fecal continence, and the natural history of the disease in the residual colon all play a role in deciding on the approach for each individual patient. Studies have indicated that segmental colonic resection with colocolonic anastomosis or even colonic strictureplasty can be performed with overall good results.174,175 However, such a strategy may be at risk for early disease recurrence within the colon.40 Even if the risk for recurrence is higher with segmental resection, the benefits of preserving the absorptive capacity in appropriately selected cases may outweigh the higher risk of recurrence.
The perianal manifestations of Crohn's disease include abscesses, fistulas, fissures, anal stenosis, and hypertrophic skin tags.176,177 Perianal Crohn's disease originates from inflammation within the anal crypts. This inflammation gives rise to sepsis and to fistulization (Fig. 33-20). Perianal Crohn's disease is common and occurs in one-third of the patients who suffer from intestinal Crohn's disease.42 Perianal Crohn's disease is usually associated with active or quiescent disease elsewhere within the GI tract. It is controversial as to whether the activity of perianal Crohn's disease parallels that of the intestinal disease. There is also controversy over whether medical or surgical control of the intestinal disease can ameliorate the perianal manifestations. Unlike idiopathic perianal abscesses and fistula-in-ano that occur in patients without Crohn's disease, perianal Crohn's disease tends to be recurrent, complex, and sometimes progressive.
Dynamic proctogram demonstrating Crohn's fistula-in-ano. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
Surgical incision and drainage are required to manage perianal abscesses (Fig. 33-21). Attempts at treating purulent collections with antibiotics alone are invariably unsuccessful. With surgical drainage of the abscess, the incision should be placed close to the anal margin. The cavity may be packed with ribbon gauze or drained with a 10–16F mushroom catheter. If a fistula tract can be identified at the time of drainage of the suppuration, a loose seton may be placed to ensure adequate drainage.
CT scan demonstrating a large perirectal abscess secondary to Crohn's disease. (Reprinted, with permission, from the University of Chicago General Surgery Archives.)
Uncomplicated submucosal or intersphincteric fistulas are best treated with an initial trial of either metronidazole or ciprofloxacin. These antibiotics are moderately effective in promoting healing of Crohn's fistulas and are associated with a low risk of complication.178,179 If a low-lying submucosal or intersphincteric fistula fails to heal with antibiotic treatment, a surgical fistulotomy can be performed. These low-lying fistulas typically heal well after fistulotomy and the risk of incontinence is low.
Surgical fistulotomies and cutting setons should not be used for suprasphincteric fistulas and should also be avoided for most transsphincteric fistulas. For complex fistulas, the risk for surgical complications is higher and more aggressive medical therapy is warranted before surgery is recommended. Medical treatment for extensive Crohn's fistulas includes the use of 6-MP, azathioprine, and cyclosporine. Probably the most effective agent at promoting healing of perianal fistulas related to Crohn's disease is infliximab. With infliximab treatment, healing of complex perianal fistulas is seen in 60% of cases.180,181 Recurrence of the fistula after infliximab is discontinued, however, may be high. Additionally, persistent stasis or sepsis within the fistula tract can impede effective healing with medical treatment. To provide for adequate drainage throughout the fistula tract, many patients may benefit from placement of setons. The use of setons with infliximab therapy can improve the overall effectiveness of infliximab.182 Typically the seton is placed prior to the initiation of infliximab therapy and then it is removed after the second or third dose.
Fibrin glue has been used for the treatment of Crohn's disease–related fistulas, but reported experience is limited. Success rates with this approach are low, but, given the low risk of complications, an attempt at fibrin glue may be worthwhile in selected cases.183,184
Closure of the internal opening of the fistula with a rectal advancement flap can be considered in cases of Crohn's disease.185 With this approach, an incision is made at the dentate line, and a flap of mucosa and muscularis is undermined and advanced down over the internal opening of the fistula. The advancement flap is then sutured into position with absorbable sutures. Rectal advancement flaps for Crohn's disease have a low risk for anal incontinence but are associated with a high failure rate. Rectal advancement flaps are not appropriate in patients in whom the rectal mucosa is involved with Crohn's disease. In severe cases of perianal disease that do not respond to aggressive medical and surgical therapy, fecal diversion with a stoma may be necessary. Diversion of the fecal stream typically results in significant relief of local inflammation and can assist in the healing of perianal fistulas. Proctectomy is indicated when perianal disease is unrelenting or when damage to the sphincters results in debilitating incontinence.
Crohn's disease carries a high risk for recurrence after surgery. The actual incidence of recurrent disease depends on the defining parameters of recurrence. For example, histological evidence for recurrence can be seen in many patients within days of surgical resection.186 Endoscopic evidence for recurrent Crohn's disease can be seen in over 80% of patients within 3 years.187 Most cases of histological or endoscopically detected recurrences, however, do not go on to produce symptoms of Crohn's disease. For this reason, histological or endoscopic evidence of recurrent disease may be used as an end point in investigative studies but are not typically used as a guide for clinical management.188
The development of symptoms related to recurrent Crohn's disease activity is the most commonly applied definition of disease recurrence, as it is the recurrence of symptoms that has the most relevance to the patient. The onset of symptoms of recurrent Crohn's disease is often insidious and the severity of symptoms varies greatly. To create a reproducible standard for recurrence of Crohn's disease symptoms, the Crohn's Disease Activity Index (CDAI) can be applied as a means of measuring recurrent disease.189,190 A CDAI of greater than 150 is generally accepted as defining clinical recurrence. Once symptoms suggestive of recurrent disease occur, it is still necessary to carry out radiological and endoscopic tests to confirm that the symptoms are in fact related to Crohn's disease.
The clearest end point as a definition of recurrence is the need for reoperation. Dates of surgery are readily documented even in a retrospective fashion. While reoperation is the most precise definition of recurrence, even this standard does not allow for accurate and reproducible comparisons between series as some centers may submit patients to surgery earlier than other centers.
Reported crude and cumulative recurrence rates vary greatly. Symptomatic or clinical recurrence occurs in about 60% of patients at 5 years, and recurrences increase with time such that at 20 years clinical recurrence can occur in between 75 and 95% of cases.35,191,192 Reports of surgical recurrence rates range from 10 to 30% at 5 years, 20 to 45% at 10 years, and 50 to 70% at 20 years.70,94,191–195 Some interesting observations regarding the pattern of recurrent disease have been made. Recurrent Crohn's disease is most likely to occur in proximity to the location of the previously resected intestinal segment, typically at the anastomosis and preanastomotic bowel.94 This is particularly true for terminal ileal disease. Additionally, the length of small bowel involved with recurrent disease parallels the length of disease originally resected.196,197 Short-segment disease tends to recur over a short segment of the preanastomotic bowel, and lengthy disease typically is followed by lengthy recurrence. Also, to a lesser degree of concordance, stenotic disease tends to recur as stenotic disease and perforating disease tends to recur as perforating disease.197
While many factors that may influence the risk of recurrence have been studied, the cumulative literature has validated very few as true risk factors. The data are conflicting for most of the proposed predictors of recurrent Crohn's disease. Much of the clinical data examining potential risk factors are confounded by poorly defined end points and improper study design. There is, however, general consensus that cigarette smoking has a significant effect on the clinical course of Crohn's disease.30 Smoking not only exacerbates existing Crohn's disease but also has been identified as a risk factor for the development of Crohn's.27,28,30 What is so striking about the effect of cigarettes on Crohn's disease is that smoking has the opposite effect on what is thought to be a very similar disease, ulcerative colitis.29 While smoking exacerbates Crohn's disease, it seems to lessen the activity of ulcerative colitis.
The mechanism by which smoking results in exacerbation of Crohn's disease is not known. Smoking is an independent risk factor for endoscopic, symptomatic, and surgical recurrence.31,32 The risk from smoking appeared to be dose-related with heavy smokers being at higher risk. This effect is reversible, as smokers who quit smoking prior to surgery can lower their risk of recurrence to a level similar to that of nonsmokers. Because of the harmful effects on the clinical course of Crohn's disease combined with the many other clearly established health hazards caused by cigarette smoking, all patients with Crohn's disease should be strongly counseled to quit smoking.
There is concern that NSAIDs may exacerbate the activity of both ulcerative colitis and Crohn's disease.70,80 Although there are no studies that have examined the specific issue of NSAIDs and the risks for postoperative recurrence of Crohn's disease, the currently available data certainly warrant some caution and patients with Crohn's disease should be advised to avoid NSAIDs.