Overview of Surgical Therapy for Crohn’s Disease

Introduction

Crohn's disease (CD) is a chronic inflammatory disease of the intestinal tract with an unknown etiology or cure. The characteristic transmural inflammation can progress to refractory inflammatory disease, stricturing disease, and fistulizing disease—all potential indications for surgery when medical management has been exhausted. An important tenant to remember is that surgery is not curative but is rather an adjunct to maximal medical therapy. Thus, a mindset of symptom control and bowel preservation is imperative as up to two-thirds of the patients will require subsequent operations in their lifetime.

Medical Treatment of Crohn's Disease

Because there is no known cure for CD, the goal of medical management is symptom control and, ideally, maintenance of disease remission. With a vast number of medications now approved for the treatment of CD, medical management is largely dictated by severity and phenotype of disease. For the treatment of mild disease, patients are often treated with 5-aminosalicylate products such as sulfasalazine, oral mesalamine (Pentasa, Asacol), or rectal mesalamine. For moderate to severe disease, corticosteroids were historically the cornerstone of medical management. However, with the US Food and Drug Administration (FDA) approval of infliximab in 1998 for the treatment of CD, we have entered an age where biologic therapy is supplanting many other therapies. Initially, biologic agents were only given to patients with severe disease, half of whom had already required surgery for complications, and a third of whom had failed to respond to thiopurines. However, post hoc analysis of the large randomized controlled trials found that overall remission rates with biologics were greater when administered to patients within 2 years of diagnosis. Thus, biologics are now being introduced to patients with moderate to severe active disease, prior to the development of strictures, whom are at a higher risk of complications. Unfortunately, up to 60% of patients experience recurrence of symptoms after induced remission with antitumor necrosis factor (TNF)α agents. In the past, most of these patients would have gone to the operating room. Now, rather than going to surgery, an alternative anti-TNFα agent (e.g., adalimumab or certolizumab pegol) or class of biologic therapy, including vedolizumab (binds integrin α4β7) or ustekinumab (binds to IL-12 and 23) is being administered. Therefore, patients are arriving to the operating room later, with more advanced disease, increasingly malnourished and immunosuppressed—arguable, a sicker patient population than before the introduction of biologic therapy.

This underscores the importance of a multidisciplinary approach to the management of these challenging, and often, medically refractory patients. The patient, gastroenterologist, and surgeon should all be in close communication as the patient's disease severity increases and surgery becomes increasingly likely. Prior to exhausting all medical options, a patient should have at least undergone a surgical consultation to understand the risks and benefits of an operation versus ongoing medical management. Ideally, consensus will be reached by all involved parties prior to the patient being taken to the operating room.

Indications for Surgery

Despite making significant advances in medical therapy, up to 70% of patients eventually require an operation. The leading indication for surgery is medically refractory disease manifested as an obstruction, fistulae, abscess, gastrointestinal bleeding, or perforation. In addition, less common indications for surgery include growth retardation in children, toxic megacolon, and fulminant colitis.

Preoperative Considerations

The decision to operate is made in the context of the patient's preoperative nutritional status, immunosuppressive regimen, and any undrained sources of infection. Total parenteral nutrition (TPN) may be indicated if the patient is severely malnourished (defined as loss of more than 5% of body weight in 1 month or 10% in 6 months, a body mass index less than 19 kg/m ² , or an albumin level less than 3 g/dL) to achieve improvement in wound healing and prevention of anastomotic leaks. This finding was demonstrated in a study of 395 malnourished patients who received 1 week of TPN prior to surgery and had significantly fewer noninfectious complications as compared to the controls (5% vs. 43%).

The impact of immunosuppressive medications on postoperative complications remains controversial. Recently, there has been a heightened focus on whether biologic therapy increases postoperative complications; while anti-TNFα therapy's impact on postoperative complications remains controversial, a recent metaanalyses including up to 18 studies concluded infliximab was associated with an increased rate of postoperative complications, reported at a rate of 15%–17%. Our recent analysis of postoperative infectious complications associated with vedolizumab administration within 12 weeks of an abdominal operation found vedolizumab to be an independent predictor of postoperative infectious complications, with a 30-day surgical site infection rate of 36% (unpublished data). Thus, the timing of surgery as it relates to the most recent dose of biologic therapy becomes important to consider, as does consideration for diversion in the setting of a primary anastomosis.

Patients with abscesses should be drained nonoperatively with interventional radiology prior to going to the operating room, unless contraindicated due to need for emergent surgery. For intraabdominal abscesses, adequate drainage may obviate the need for surgery altogether; if not, it at least minimizes the degree of intraabdominal inflammation allowing for a more limited bowel resection. If infection or abscesses are present at the time of the operation, the surgeon should consider postoperative antibiotic therapy and delayed closure of operative incisions.

Once it is decided that the patient will proceed with surgery, the surgical plan should incorporate detailed information from imaging, endoscopy, and prior operative reports. Cross-sectional imaging with CT enterography (CTE) or MR enterography (MRE) provides important information about the distribution and extent of disease, any undrained fluid collections, anatomic location of fistulizing disease, alteration in anatomy due to prior operations, and an estimate of remaining small bowel length. MRE has the added advantage of no radiation with improved anatomic detail, especially important in this young population who will likely require several repeat abdominal images over the course of their lifetime.

A final important step prior to taking a patient to the operating room is a discussion regarding the potential construction of a permanent or temporary stoma. Because anxiety around stoma formation is common among CD patients, early comprehensive education and support from an enterostomal therapist is important. Additionally, it is important to consider preoperative stoma marking if the patient has any suspicion of requiring a stoma, especially in complex reoperative CD where unexpected intraoperative findings or technical difficulties may mandate stoma construction.