Crohn's Disease Obstructions

Abstract

Obstruction from stricturing Crohn's disease remains one of the most common reasons for intervention. Acute inflammation is often responsive to medications, but chronic fibrosis is unlikely to respond and will generally go on to require additional treatment. Newer methods, such as endoscopic balloon dilation, are gaining grounds in strictures that are amenable, but with high recurrence and strictures that may not be endoscopically accessible, surgery still plays a key role in the treatment of obstructing Crohn's disease.

Stated Objectives

The objective of this article is to provide the clinician with an overview of obstructing CD, which has arisen most commonly from strictures. The clinician will have a better understanding of the medical, endoscopic, and surgical options for obstructing strictures in CD and how best to manage a patient with this problem.

Introduction to the Problem

A stricture, or an abnormal narrowing of the intestine, can lead to partial or complete obstruction in CD. This is not an uncommon problem which often leads to surgical intervention. Historically, as many as 71% of patients required one surgical intervention for abdominal CD within 10 years of diagnosis and over half of these were for obstruction. ¹ Not surprisingly, intestinal obstruction is the most frequent complication of small intestine CD. ^{2 3} There are different phenotypic behavior patterns of CD including nonstricturing/nonpenetrating, stricturing, and penetrating, ⁴ but stricturing type is the most common in ileal disease and in patients diagnosed with CD at a younger age. ³ Strictures are also more common at anastomotic sites between the small and large intestines. Pure colonic strictures occur with less frequency. There are many risk factors associated with surgery in CD, but specifically those more likely to require surgery for stricturing and obstructing CD are associated with an enteroenteric fistula, proximal small bowel dilation >3 cm, or abscess/phlegmon. ³ And when looking at the location of disease as a predictor, as many as 87% of the patients with ileocecal disease eventually require resection for stricture. Unfortunately, there is a relatively high rate of recurrence of symptoms over time, estimated to be 36% for symptomatic recurrence by Toh et al. ³

Epidemiology

Acute Obstruction

Acute inflammation in CD causing obstruction is more likely to be amenable to medical therapy. ² However, approximately 75% of the patients diagnosed with an acute Crohn's stricture go on eventually to need some sort of intervention. This may be endoscopic or surgical. ⁵ Acute strictures are characterized by bowel wall edema as compared with the fibrosis of a chronic stricture. The acuity can often be differentiated on high-quality imaging such as CTE (computed tomography enterography) and MRE (magnetic resonance enterography), which have dramatically improved in recent years. In acute disease with obstruction, there is mucosal enhancement and may be thickening on the CTE, but it is dependent on how well the bowel is distended. On the MRE, mucosal hyperenhancement occurs with acute inflammation as well as thickening of the bowel wall manifested on T2-weighted sequences. This differs from chronic disease as chronic fibrotic bowel may appear thickened but may lack T2 hyperintensity. ⁶

One group specifically looked at MRE features and whether they could show an association with an increased risk of eventually requiring surgery. The majority of those who underwent surgery, did so within a year. They found that when the following three MRE characteristics were present, patients had a poorer prognosis despite maximum drug therapy and were more likely to require surgical intervention: bowel wall thickening at the stricture of >10 mm, stricture length of >5 cm, or prestenotic dilation of >30 mm. The positive predictive value for these three factors in combination was 81%. Conversely, when none of these features existed, the majority of patients were able to avoid surgery, with a negative predictive value of 83%. ⁷ The use of high-quality imaging can help with counseling of patients and can help the clinician understand the likelihood of treatment success.

Risk factors for acute Crohn's flares have been thought to include elements such as cigarette smoking, nonsteroidal anti-inflammatory drug use, antibiotics, infections, and there is also evidence for increased emotional stress. ^{1 8}

Free perforation in acute obstruction is rare but may occur in 1 to 3% of cases. The transmural nature of CD makes it more likely to occur than ulcerative colitis. More commonly, however, a Crohn's perforation results in a focal or sealed perforation with abscess—also called a contained perforation. While important to always consider etiologies on the differential such as adenocarcinoma or an endoscopic perforation if the patient had a recent procedure, acute exacerbations of chronic disease in the presence of an obstruction is a far more common cause of perforation. ⁹

Chronic Obstruction

Stricturing and obstruction typically occur over time and happen most commonly in the ileum. Small bowel strictures are less likely to be malignant, however, if a large bowel stricture or obstruction occurs, one should always keep malignancy on the radar. ⁵

The majority of Crohn's obstructions are from chronic strictures that are fibrotic in nature ( Fig. 1a–c ). Despite newer, more targeted therapies, there is no medication to specifically target the chronic fibrosis of Crohn's strictures, and thus the need for surgery remains. ¹⁰ The process and mechanism of fibrosis is very intricate and complex which has led to the difficulty so far in finding a targeted drug therapy specifically for the fibrosis. It is thought that the accumulation of extracellular matrix ultimately leads to tissue fibrosis and intestinal structuring/obstruction but there are many different mechanisms that may contribute and many different cell types that lead to the increased secretion of extracellular matrix. ¹⁰ Fibrosis is an exaggerated response of these processes with accumulation of extracellular matrix. ¹¹ And in CD there can be an imbalance between extracellular matrix deposition and breakdown. ¹¹ Important to remember is that anti-inflammatory medications/therapies, do not necessarily have antifibrotic effects. The fibrosis can occur in all layers of the bowel wall due to the transmural nature of CD. There are both inflammation-dependent and inflammation-independent mechanisms which lead to fibrosis in CD and these mechanisms have not been fully defined which again makes targeted drug therapy much more difficult.

Fig. 1.

( a ) Crohn's stricture with proximal dilatation (note the fibrostenotic appearance of the proximal small bowel). ( b ) Maximal chronic dilatation of the small bowel. ( c ) Axial image of small bowel stricture.

Malignant strictures causing obstruction in CD, while still rare, are more common in colon than in small bowel. Small bowel adenocarcinoma is found at stricture sites <1% of the time, ¹² whereas in patients with colonic strictures the malignancy rate historically was reported as high as 6.8%. ¹³ Because of this known increased risk of cancer associated with colonic Crohn's strictures, the traditional teaching was that the segment should be surgically resected, however, a more recent study showed a rate of 0.8% of cancer in Crohn's colonic strictures. There was an overall rate of 2.4% of strictures with any dysplasia or cancer. ¹⁴ A bowel obstruction from a large tumor can also occur, just like in patients without CD, however, the risk of colorectal cancer is higher in patients with CD with an increased incidence rate ratio of at least 2.64 over the general population. ¹⁵

Treatment Options

Medical Management

Once an abscess and free perforation are ruled out, initial management for Crohn's structuring with obstruction is usually medical therapy. Acutely this often includes nasogastric decompression and steroids. The majority of obstructions will resolve with these measures, but need to transition to a long term maintenance medication as long term steroids come with definite risk. If the obstruction is unresponsive to medical therapy, then they will need an intervention ⁹ as in 66% of the patients with stricturing CD medical therapy is unsuccessful ( Table 1 ). ¹⁰

Table 1. Crohn's obstruction intervention options.

Intervention	Acute vs. chronic stricture	Configuration of stricture	Options
Medical	Acute	Any	1. Steroids 2. TPN and bowel rest (temporizing) 3. Maintenance medication.
Endoscopic	Chronic	1. Endoscopically accessible 2. Length <5 cm 3. Nonangulated.	1. Balloon dilation 2. Intrastricture steroid injection not recommended.
Surgical	Chronic	1. Unreachable with endoscope. 2. Multiple strictures 3. Long length 4. Failed endoscopic management.	1. Resection reanastomosis. 2. Stricturoplasty.

For acute flares, corticosteroids have been used since the first study was published in 1955 demonstrating their utility in the treatment of severe attacks in inflammatory bowel disease. ¹⁶ They are used primarily to reduce the signs and symptoms of active or acute CD. For mild to moderate disease, or partial obstruction, oral steroids may be used but for moderate to severe disease intravenous formulations should be used along with hospital admission. The corticosteroids help “bridge” symptoms to control and allow time for an immunomodulator and/or biologic agent to take effect. ¹⁷ The steroids can then be tapered off and the maintenance medication is continued.

Despite increased use of immunosuppressants over the years we have yet to consistently show a convincing decrease in the need for surgical intervention specifically when related to the occurrence of stricturing and perforating complications. ¹⁸ There has been no evidence of the decrease in the progression of inflammation to stricturing or penetrating CD and while Jeuring et al found an overall decrease in the rate of surgery requirements from 1990s to 2000s when biological and immunomodulator therapies were increasing, the characteristics of the type of surgery show an actual increase in the number of patients presenting with stricturing disease to their surgeon (34.1 > 37.6 > 51.4% p  = 0.03). ¹⁹

TPN and Bowel Rest

In 1960s and 1970s, total parenteral nutrition (TPN) and bowel rest were looked at as a possible primary treatment in CD. This was derived from some observational studies which saw TPN obviating the need for surgery in some patients. The thought was that extended bowel rest, which TPN could allow, may be a treatment in itself for CD. But in 1985, Ostro et al reported their randomized controlled trail of bowel rest and TPN for CD. They found that when comparing a group on total bowel rest with TPN to a group with enteral formula and another with partial parenteral nutrition but ad lib oral intake, there was no difference in remission rate at 21 days. They felt confident that this showed bowel rest alone was not an appropriate treatment for CD. The conclusion from this study was that TPN should be restricted to supportive use rather than primary therapy. ²⁰

TPN as a modality to help prepare a patient for surgery has been examined. The complication rate following surgery for CD has been observed to be as high as 30%. ²¹ It is well established that malnutrition is a risk factor for complications, so Ayoub et al looked at whether or not they could demonstrate an advantage to preoperative TPN in CD. They were able to show in a multivariate analysis that preoperative TPN for ≥60 days prior to surgery significantly reduced noninfectious complications when operating on CD. They also showed that weight loss >10% in the past 6 months was an independent risk factor for both infectious and noninfectious complications. ²²

Endoscopic Management

Balloon dilation or “stricturotomy” for fibrotic strictures is an option employed by some advanced endoscopists. Ballooning success rates have been reported as high as 89 to 92% with up to 81% of patients having at least short-term relief of symptoms. ⁵ This relief does go down over time with long-term results showing 43% eventually undergo surgery. In general, strictures ideal for endoscopic balloon dilation are those that are accessible endoscopically, those with a length of ≤5 cm, and those that are considered “nonangulated” or are relatively straight. ¹⁰ There are conflicting results as to whether or not the presence of some active inflammation on endoscopy or an elevated CRP is associated with short- or long-term failures, but active cigarette smoking seems to be associated. ²³ Additional or repetitive dilation of the same area has been studied as well. In the setting of starting on a new or escalated medical regimen (i.e., Immunomodulators or biologics), repeat dilations may be reasonable. In this particular cohort with repeat dilations, the surgery free rate was still 57% at 24 months. ¹⁰

The two largest benefits of endoscopic balloon dilation include the minimally invasive approach and preservation of bowel length by avoiding a resection. Most commonly, this is a technique used in the terminal ileum but can also be used at an ileocolic anastomosis. ²⁴ In 2017, Bettenworth and colleagues published a pooled analysis of endoscopic balloon dilation for Crohn's strictures causing obstructive symptoms. Most were in the ileum (81.5%) and were anastomotic strictures (58.3%). Measures of short-term efficacy included the ability to dilate the stricture and see improvement in the lumen. The main factors associated with a higher rate of short-term success were de novo strictures, compared with anastomotic strictures (odds ratio [OR] 2.3, p  < 0.001) and ability to dilate to a greater maximum diameter (OR 1.4, p  < 0.001). The measure of long-term efficacy was the time until another intervention was needed. While in the short term, de novo strictures were found to have a higher technical success rate, the clinical efficacy was not actually associated with location or type of stricture nor the maximum dilation diameter. They did find that for every 1 cm increase in stricture length, the hazard ratio for eventually needing surgery increased by 8% ( p  = 0.005). They also evaluated a stricture length cutoff for surgery-free outcome and found that strictures ≤5 cm were associated with surgery-free outcomes and were less likely to need repeat dilation. Major complications occurred in 2.8% of the procedures and included perforation, bleeding, and dilation-related need for surgery. And with a median follow-up of 36 months, 47.5% of patients had a symptomatic recurrence and 28.6% went on to have surgical intervention. ²⁵

Other endoscopic treatments for obstructing strictures, such as corticosteroid injections have been looked at, but the data so far does not support this. ¹⁰ A trial was started to look specifically at intralesional corticosteroids, but it was stopped early due to a trend toward harm. ²⁶ Both the American College of Gastroenterology and the British Society of Gastroenterology do not recommend routine use of this technique. ^{27 28}

Specifically, in colonic strictures, as discussed above, the cancer rates at strictures are now thought to be <1%, so endoscopic dilation is a reasonable management option. In a study published by Chang et al, endoscopic treatment was successful in 76% of colonic strictures. ²⁹

Surgical Management

Surgical management has historically been the go-to for treatment of obstruction from Crohn's stricturing, but as discussed above, endoscopic techniques have decreased the need for surgery, but definitely not eliminated its role. Of course, obstruction in CD from a tumor is still surgically managed.

There are several decision points once surgery is deemed necessary. These include surgical approach: laparoscopic versus open, and management of the stricture: stricturoplasty versus resection.

Laparoscopy has been gaining traction in all intestinal resections but its use for complex CD and especially recurrent disease is less prevalent and more controversial. With a wide range of conversion rates reported, from 6.7 to 42.3% in recurrent CD, most commonly from adhesions, ³⁰ many surgeons just plan for an open procedure. To delve deeper into this question, Shigeta et al did a meta-analysis and were able to show that there was no significant difference in the incidence of overall complications between laparoscopic approach for primary or recurrent CD. Not surprisingly, they found the conversion rates to be much higher in re-operative cases than in primary cases, but again there was no difference in complications so felt the approach was justified in recurrent disease as well. ³¹ The benefits of laparoscopic surgery for CD have also been studied and many report that compared with open procedures, it is a safe and feasible approach associated with a shorter length of stay and does not significantly increase the postoperative complication rate. ^{32 33 34}

Because CD can affect any region of the intestinal track, if the bulk of the affected areas is in the small intestine and a patient requires extensive or repeat surgeries, it can lead to short bowel syndrome. For this reason, stricturoplasty in the small intestine should be considered instead of resection if possible. Landerholm and colleagues studied the short- and long-term outcomes of stricturoplasty and found that the complication rate was similar between patients who had a stricturoplasty alone, a resection with anastomosis alone, or both. In their 130 patients, two developed anastomotic leaks and one a leak at the stricturoplasty site. Symptomatic obstruction recurred in 47% and 22% of patients went on to have another operation in the 5-year follow-up period. Patients were more likely to need an additional surgery if they underwent a stricturoplasty and resection at the time of initial surgery ( p  = 0.039). ³⁵ This may imply they had a more aggressive disease pattern to begin with.

When deciding on appropriateness of stricturoplasty for Crohn's obstructions, important things to consider include the amount of palpable inflammation. Stricturoplasty is generally best for chronic, fibrotic strictures. Other indications include multiple strictures within a long segment of bowel or known short bowel syndrome. Contraindications include multiple strictures in a short segment of bowel, a stricture close to the site of a resection, significant acute inflammation, perforation, or significant malnutrition. ³⁶ General recommendations also include taking a biopsy of the stricture site when the bowel is open to rule out cancer. Regarding intestinal bypass with exclusion of a segment, this is a more historic consideration and should only be considered as a temporizing measure or in situation where there is no alternative. ²

Stricturoplasty options are broken down based on location and length of stricture. The options for jejunoileal strictures include Heineke-Mikulicz for short segments (<5–10 cm) and for longer segments the Finney or Jaboulay (10–20 cm). The Heineke-Mikulicz stricturoplasty is similar to a pyloroplasty for pyloric stenosis. An antimesenteric enterotomy is made longitudinally over the stricture and extended onto normal bowel on either side. This is then closed in a transverse fashion with absorbable suture. The Finney stricturoplasty, again starts with an antimesenteric enterotomy extending onto normal bowel on both sides, the strictured area is folded onto itself, suturing the posterior edges in a running fashion and then closing the anterior edges in an interrupted fashion. ³⁶ Also for longer strictures, but again perhaps more historically relevant, is the Jaboulay technique where the stricture is bypassed in a side-to-side fashion because of how narrow it is and the concern that it would not hold suture. Lastly there is a side-to-side stricturoplasty, first described by Dr. Michelassi in 1996 for strictures >20 cm. This involves division of the small bowel and mesentery at its midpoint and moving the proximal loop over the distal one in a side-to-side fashion placing stenotic areas of one limb next to dilated areas of the other limb. A back row of sutures is placed and then an antimesenteric longitudinal enterotomy is made on both limbs followed by placement of an internal row of absorbable sutures. This suture is then continued anteriorly and then the anterior suture row is reinforced with an outer layer of interrupted suture. ³⁷

Fortunately, rarely is operative intervention on duodenal obstructive disease warranted. Stricturoplasty using Heineke-Mikulicz technique may be considered, but gastrojejunal bypass is generally the procedure of choice. ²

Stricturoplasty is generally utilized on small bowel, however, can also be used to treat ileocolic strictures. The use of stricturoplasty on colonic strictures is still unknown but not widely utilized. For localized disease, an isolated colonic stricture can be safely managed with a segmental resection and primary anastomosis. However, if a patient is malnourished or on steroids, a resection and ostomy creation may be the safest option. And finally, in the setting of multiple colonic strictures or multiple areas of active colonic Crohn's disease, a total colectomy may be most appropriate ³ ( Fig. 2 ).

Fig. 2.

Colonic Chron's stricture.

Principles of resection for Crohn's obstruction follow the same guidelines as any intestinal resection for Crohn's disease, to resect back to grossly normal bowel to avoid removing excess intestine ( Fig. 3 ).

Fig. 3.

Small bowel stricture with dilated proximal intestine.

Summary

In summary, bowel obstruction from Crohn's disease is a known and common entity that has persisted despite advances in medical management over the years. The most important factors when considering treatment include high quality cross-sectional imaging (CTE or MRE) to evaluate the stricture, consideration of a trial of medical therapy, addition of parenteral nutrition if severely malnourished, and then location and number of strictures. For strictures that are amenable, endoscopic balloon dilation is a newer technique to help with symptoms and holds some promise. Surgery still has a strong role in the treatment of obstructing Crohn's strictures and based on surgeon's experience, patient history, and nature of disease, laparoscopic or open approach with segmental or stricturoplasty or both are the available options.