Large Bowel

Mechanical Bowel Preparation

Two types of MBPs exist: hyperosmotic versus isosmotic ( Table 1 ). Hyperosmotic MBPs (e.g., magnesium citrate, sodium phosphate) exert an osmotic effect, drawing fluid into the bowel lumen, as a mechanism of flushing out colonic contents. Although patients are able to tolerate ingestion of these lower volume formulations, they cause electrolyte and fluid imbalances and dehydration. Patients subsequently become orthostatic and may develop acute kidney injury. Contraindications to hyperosmotic solutions include renal failure, acute coronary syndrome, congestive heart failure, bowel obstruction, ileus, intestinal malabsorption, and ascites. The use of hyperosmotic MBP solutions is not recommended in current consensus guidelines for ERPs.

ERAS consensus guidelines recommend the utilization of isosmotic MBPs, which consist of osmotically balanced, nonabsorbable solutions that do not produce significant fluid or electrolyte shifts. Isosmotic bowel preparations are deemed safe in patients with the comorbidities of hepatic disease, congestive heart failure, and renal failure.

Large volume polyethylene glycol (PEG) preparations include GoLYTELY, Colyte, NuLytely, and TriLyte. Patients have difficulty tolerating these large-volume solutions as they are not palatable and cause nausea and emesis in 4% to 17% of patients. New low-volume PEG (1–2 L) preparations combined with other agents have been developed and include MiraLAX, HalfLytely, MoviPrep, and BiPeglyte.

There are multiple studies/clinical trials and meta-analyses that show conflicting results for the effectiveness of MBPs in regard to surgical outcomes. In a Cochrane review in 2011, 18 randomized controlled trials were reviewed that included 5805 participants; 2906 patients were administered MBP while 2899 received no bowel preparation before elective colorectal surgery. There was no statistically significant difference between the MBP and non-MBP groups in regard to anastomotic leak for colonic resections and low anterior resection. These results are similar to a recent meta-analysis, published in 2018, evaluating eight studies with 1065 patients. However, both studies have reported that evidence quality is low due to the variation in bowel preparations. Because of this, MBP alone is generally not recommended for elective colorectal surgery.

Oral Antibiotics

First-line antibiotics include a combination of oral neomycin sulfate plus oral erythromycin base or oral neomycin sulfate plus oral metronidazole ( Table 2 ). The most common side effects are nausea and emesis. Multiple randomized controlled trials have reported a significant improvement in SSIs with the use of OA. Two large studies from American College of Surgeons National Surgical Quality Improvement Program (NSQIP) (>300,000 patients) and one large meta-analysis of prospective studies (69,000 patients) have confirmed that many medical centers are using OA alone for their bowel preparations before colorectal surgery. These studies suggest that OA alone is associated with similar SSI rates to OA plus MBP and lower SSI rates as compared with both MBP alone and no bowel preparation.

Currently, there is a prospective randomized controlled trial using the Rethinking Clinical Trials (REaCT) platform and NSQIP to compare no bowel preparation versus preoperative OA alone to evaluate SSI rate in elective colorectal surgery. Results are pending at this time. A similar multicenter randomized controlled trial was performed in Spain (ORALEV) in which 536 patients were randomized to no OA versus OA. The incidence of SSI in the no OA group (30/269, 11%) was significantly higher than in the OA group (13/267, 5%) (χ ² test, p = 0.013). The no OA group had more complications (76/269, 28%) compared with the OA group (51/267) ( P = 0.017).

Clinical Presentation and Diagnosis

Uncomplicated acute diverticulitis is typically located in the sigmoid colon and characterized by the symptom triad of left lower quadrant pain, fever, and leukocytosis. A mobile sigmoid colon or atypical manifestation in other segments of the colon can lead to abdominal pain in locations other than the left lower quadrant, such as the suprapubic region or even the right-side of the abdomen.

Severe complications occur in approximately 25% of cases and can complicate the diagnosis of underlying diverticulitis. Complications involve abscesses that occur in 30% of cases, fistula in 14%, and free perforation with peritonitis in 1% to 2% of patients. Colonic stricture with subsequent bowel obstruction is uncommon. For patients with complicated diverticulitis, medical treatment may be ineffective, and the majority require surgical intervention. Complications can be highly variable, and differential diagnoses must be excluded; therefore findings on physical examination and on blood and urine analyses should be further evaluated with diagnostic imaging. Computed tomography (CT) is the mainstay imaging modality in the assessment of acute diverticulitis and accompanying complications. A CT of the abdomen and pelvis with intravenous and oral contrast is used to evaluate the severity of inflammation and the presence of bowel strictures, obstruction, and local or distant complications such as abscesses and fistulas. In patients with contrast allergy, a noncontrast study or an alternative approach may be performed (e.g., magnetic resonance imaging or ultrasonography), particularly in the pregnant patient. Ultrasonography may identify a hypoechoic colonic wall with a fecalith obstructing the diverticulum, an adjacent bowel wall, and mesenteric edema, which may indicate abscess formation. The diagnostic accuracy of ultrasound is, however, dependent on the examiner’s skill and experience.

Classification of diverticulitis is essential to follow a standardized treatment algorithm that provides the highest success rates for disease management. The Hinchey classification, originally published in 1978, is used as a basis to provide evidence-based management strategies for patients with diverticular disease. The modification by Wasvary et al. is widely used and is based on CT findings concerning abscess formation and peritonitis ( Table 1 ). Both imaging and clinical evaluation are required for a complete patient assessment.

Management of the Patient with Acute Diverticular Disease

Diverticular Disease with Pericolic Abscess

Complicated diverticulitis that is accompanied by either a mesocolonic (stage Ib) or more distant abscess formation (stage II) occurs in 15% to 40% of acute diverticulitis patients. It can be treated nonoperatively with antibiotics in an outpatient setting in stable patients with abscesses ≤3 cm in size. Abscesses >3 cm or patients who do not respond to antibiotic treatment alone require percutaneous drainage, typically via a transabdominal approach ( Fig. 1 ). Alternative approaches are transgluteal for pelvic abscesses (even though they are associated with greater patient discomfort and a higher risk of drain dislocation) and transvaginal or transrectal approaches. Conservative treatment strategies are typically effective with small abscesses, with an overall success rate in 80% of patients presenting such abscesses. There is a failure rate of up to 34% with nonoperative treatment of abscesses >3 cm in size.

If the patient is in stable condition with nonoperative treatment, the diet is gradually advanced to a low-residue diet. If a CT-guided drain is placed, decreasing white blood cell and drain output to <30 mL/day indicate when the drain can be considered for removal. In many cases, a drain contrast study will show the size of the residual abscess cavity and whether there is a communication to the colon. The rate of recurrent abscesses after conservative treatment is high, although it is considerably lower after percutaneous drainage (25%–60% vs. 15%–25%). The overall failure rate of these nonoperative approaches is 15% to 32%. In case of failure, surgery is indicated, with urgent abscess drainage and colectomy, typically with primary anastomosis and proximal diversion.

Treatment of Sequelae of Complicated Diverticulitis

Surgical Treatment

Clinical Presentation and Diagnosis

Three to five percent of patients with diverticular disease develop diverticular bleeding, presenting as either bright red blood per rectum, hematochezia, or melena. Risk factors include the use of NSAIDs, thrombocyte aggregation inhibitors, and anticoagulants, which is common among the elderly. Although diverticular bleeding can cause severe blood loss, it will stop spontaneously in approximately 80% of cases. The overall mortality rate is 2% to 4%. Recurrent bleeding is common and occurs in up to 38% of patients.

Diverticular disease is the underlying cause of more than 40% of cases of lower gastrointestinal bleeding. Typically, patients present with painless hematochezia. Initial standard management includes establishing large-gauge peripheral intravenous access at two different sites, cardiopulmonary monitoring, and supplemental oxygen. Initial laboratory analyses should include complete blood count, electrolytes, liver parameters, lactate levels, and coagulation parameters if the patient is on anticoagulant therapy. Hemoglobin levels are serially reevaluated, and blood transfusion is considered according to the patient’s clinical status and the dynamics of changing hemoglobin levels. A hemoglobin level of 6 g/dL absolutely indicates the need for a blood transfusion in the acute setting. Patients with a history of cardiovascular disease should receive blood at an Hb level of 8 g/dL, and a level of 10 g/dL should be maintained.

Recommendations for withholding anticoagulants or antiplatelet drugs in patients with acute diverticular bleeding are based on moderate to low quality evidence. The type of drug, the history of the patient determining their individual thrombotic risk, and their clinical status should all be considered. Aspirin as a primary prophylaxis for cardiovascular events generally can be continued, even perioperatively in the case of emergent surgical treatment. In patients with a low thrombotic risk and unstable gastrointestinal hemorrhage under warfarin therapy, anticoagulation can be immediately reversed using prothrombin complex and vitamin K. Once the bleeding has stopped, warfarin therapy should be restarted after an interval of 7 days. In case of high thrombotic risk (mechanical heart valve, atrial fibrillation with a prosthetic heart valve or mitral stenosis, recent venous thromboembolic event [within prior 3 months]), however, the pausing of warfarin therapy has to be evaluated carefully. Anticoagulant therapy with heparin can be considered as a transitional solution in an emergency setting. With heparin therapy, monitoring the partial thromboplastin time (PTT) every 6 hours is essential. Dosing should be carefully adjusted according to PTT levels and body weight.

The two main diagnostic approaches to distinguish diverticular bleeding from other etiologies of lower gastrointestinal bleeding are colonoscopy and computed tomography angiography (CT-A).

Overview

The 10-year cumulative risk of colectomy for patients with UC is 10% to 15%, and the rate appears to be decreasing in the era of biologics. Despite evolving medical therapies, patients come to surgery for three main reasons: (1) failure of medical management to control either the intestinal or extraintestinal manifestations of UC, (2) dysplasia and colorectal cancer, or (3) toxic megacolon.

The first is far and away the most common indication for surgery. A patient with UC is cured of colitis by removing the entire colon and rectum (from the terminal ileum to the anorectal junction). This stands in contrast to Crohn’s disease where surgery is used to address immediate symptoms, but there is always the risk of the disease returning in a new area.

Patients with UC are at higher risk of colorectal cancer and require routine endoscopic surveillance beginning 8 to 10 years after disease onset or sometimes sooner. Colonoscopy should occur every 1 to 3 years depending on risk factors such as PSC, a family history of colorectal cancer, and whether active inflammation is present. In the past, patients with dysplasia were encouraged to undergo surgery due a high rate of colorectal cancer even with immediate colectomy. Now with improved endoscopic techniques, patients with visible and resectable dysplasia can be safely followed with close colonoscopic surveillance by experienced gastroenterologists using dye spray or virtual chromoendoscopy and high-definition endoscopes. In the event of persistent invisible multifocal or high-grade dysplasia, unresectable dysplasia, or colorectal cancer on biopsy, patients should undergo proctocolectomy.

Patients with advanced disease despite maximal medical therapy may also progress to toxic megacolon, characterized by colonic dilation, fevers, tachycardia, leukocytosis, and abdominal distension. This requires urgent surgical intervention to prevent perforation.

While the surgical concepts are the same for all UC patients, the approach should be tailored to each patient’s indications, urgency, comorbidities, and severity (corticosteroids, biologics, nutritional status) as well as long-term goals of care with regards to life with an ostomy versus bowel frequency. Shared decision making and a team-based approach with the patient, family, gastroenterologist, and surgeon should be embraced to ensure that the patient is knowledgeable and prepared for the operation(s) and long-term impact on lifestyle.

Total Abdominal Colectomy with End Ileostomy

For urgent indications (toxic megacolon, severe medically refractory disease, refractory ASUC, perforation), total abdominal colectomy with end ileostomy is the best course of action. It is a relatively short operation (2–3 hours) that removes a good amount of diseased bowel (colon) and diverts the fecal stream away from the rectum, allowing the mucosa to partially heal. The rectum is left in place during this operation to reduce the risk of complications associated with pelvic dissection in the setting of severe inflammation and to allow for restoration of fecal continence via an ileal pouch later. Before surgery, if time allows, the patient should have a visit with an enterostomal therapist and the site for the end ileostomy should be selected. It is usually in the right lower quadrant, but it is important that it is tailored to the patient’s body habitus. A poorly placed ileostomy (in a skin fold or scar, belt line, etc.) can be very challenging to manage, time consuming, and lifestyle limiting for the patient and family.

The approach should be laparoscopic if the surgeon has experience and the patient is hemodynamically stable. A fully laparoscopic, hand-assisted laparoscopic, or robotic approach have all been described. In general, after the pneumoperitoneum is established, the colon is mobilized, either with a medial to lateral approach with ligation of the vessels first (ileocolic, middle colic, and inferior mesenteric) or lateral to medial approach with ligation of the vessels second. High ligation is not needed unless there is concern for dysplasia or malignancy, and it is generally safest to stay close to the colon when dividing the mesentery.

In a medial to lateral approach, the dissection begins on the left by the sigmoid colon, which is retracted anteriorly to identify the inferior mesenteric artery pedicle. A window is created to isolate the pedicle, and before ligation it is important to identify and preserve the left ureter and gonadal vessels. After ligation, the dissection then proceeds superiorly separating the colon from Gerota’s fascia up to the splenic flexure. The lateral attachments are taken next, following the white line of Toldt to free the descending colon from the retroperitoneum. Division of the rectosigmoid junction with a stapler is performed next, followed by ligation of mesenteric vessels. Attention is then turned to the right colon with identification and ligation of the ileocolic artery. The medial dissection proceeds superiorly toward the hepatic flexure, followed by a lateral dissection releasing the peritoneal attachments. After dividing the hepatic flexure, all remaining attachments along the transverse colon are divided. The colectomy is completed with division of the terminal ileum. Of note, based on surgeon preference, the dissection either proceeds from left to right (as described) or right to left.

There are a few key considerations when selecting the proximal and distal resection sites. The rectosigmoid junction should be divided either intracorporeally or extracorporeally (via Pfannenstiel or lower midline incision). If the rectosigmoid bowel is thick and edematous, it is possible that the staples will not hold. If there is concern, the selected division point should allow for the rectosigmoid area to be matured to the skin as a mucous fistula. Other strategies for managing a challenging rectal stump include oversewing the staple line and decompressing the rectum with a rectal tube. Delayed intraabdominal breakdown of the rectal stump results in sepsis and usually needs to be managed with reoperation. The proximal division should be in the very distal terminal ileum so that sufficient small bowel remains for an ileal pouch if the patient desires.

After the colectomy specimen is removed, the ileostomy should be brought out through the previously marked area and everted or “Brooked.” By having the ileostomy above the skin, it will allow for a well-fitting ileostomy appliance and reduce risk of skin breakdown, pain, and discomfort. When bringing the ileostomy through the abdominal wall, it is also important to ensure that the mesentery of the small bowel is not twisted as this can lead to obstruction and/or ischemia requiring reoperation.

For most patients, the total abdominal colectomy will restore appetite, weight, energy, and overall quality of life. There will be some bloody mucus drainage from the rectum, but if patients are warned to expect this it is usually quite manageable.

Completion Proctectomy/Total Proctocolectomy

For patients undergoing surgery for dysplasia, cancer, or chronic medically refractory disease (not hospitalized, not on high dose steroids, and without signs of malnutrition), the best approach is to remove the colon and rectum (total proctocolectomy) in one operation. In this case, the patient and surgeon should plan to either proceed with ileal pouch anal anastomosis (IPAA) with a temporary diverting loop ileostomy or simply remove the rectum and remain with a permanent end ileostomy. If the plan is to complete the proctocolectomy in one operation, the colectomy is completed as described before and the rectum is removed as described later.

Proctectomy can be completed laparoscopic, hand-assisted laparoscopic, robotic, or open. The rectum is identified, and the inferior mesenteric artery is noted coursing along the retroperitoneum. The peritoneum is incised, and the left ureter is identified. The inferior mesenteric artery and vein are ligated. The dissection is then carried into the pelvis posteriorly by developing the plane between the mesorectum and the fascia propria of the rectum. The superior hypogastric plexus should be identified and preserved. Once the pelvic floor is reached, the anterior dissection should be initiated by developing the plane between the rectum and prostate or vagina. Care should be taken to err on the side of the rectum and, in men, avoid entering Denonvilliers’ fascia as nerves controlling sexual function course around the pelvic brim and are at risk of injury. The lateral stalks of the rectum should be divided on the right and left, and the rectum should now be free circumferentially to the pelvic floor. This can be confirmed by placing a finger in the anus. If the patient is not to have an ileal pouch constructed, the rectum and anus will be completely removed by completing the dissection from the anus. This dissection is initiated with a self-retaining retractor effacing the anus. It is generally a simple dissection conducted from the perineum in the intersphincteric (between the internal and external anal sphincter) groove. This is usually bloodless and leaves the external sphincter in place to help with perineal wound healing and prevent herniation later.

The perineum is closed in multiple layers approximating the muscle layers using Vicryl or other absorbable suture, followed by skin closure. Surgical closed suction drains are typically left in the presacral space to protect the perineal wound from seroma formation and reduce the risk of infection and dehiscence.

Creation of Ileal Pouch Anal Anastomosis

Most patients will desire ileal pouch creation; IPAA is the most common operation done for UC in the United States. Although it is associated with more risks (short and long term) than end ileostomy, for many patients restoring intestinal continuity is important to their quality of life. For most patients with an IPAA, it is reasonable to expect 6 to 10 bowel movements per day. The stool will be looser, although consistency may improve with time as the small bowel adapts to absorb some water. A significant number of patients will experience urgency and even some fecal incontinence, but for the most part the pain associated with bowel movements is gone.

It is important to recognize scenarios where IPAA is not appropriate. These include patients with a history of fecal incontinence or sphincter injury, history of anorectal disease (anal fistula), uncertainty related to the diagnosis of UC versus Crohn’s disease (indeterminate colitis or IBD unclassified), and those who are frail and would not be able to tolerate the complications associated with IPAA (pelvic sepsis). IPAA should not be undertaken in patients with Crohn’s disease except by expert surgeons in specific situations as it is associated with a much higher rate of postoperative complications and pouch failure.

If the plan is to create an ileal pouch, when the rectal dissection is at the level of the pelvic floor, the rectum is transected with a stapler, approximately 1 cm above the anal sphincters. After the rectum is removed, the ileal pouch is created. If the colectomy was done in a prior operation, the terminal ileum is freed up from the ileostomy site. The distal terminal ileum is identified as is the superior mesenteric artery. The “tip” of the small bowel is located—the area of the small bowel that will reach the furthest into the pelvis. This is usually 10 to 15 cm proximal from the distal end. If this “tip” can touch the pubic bone, it will likely reach the anus. The two limbs of the ileal pouch are aligned, and a linear stapler is used to fashion the pouch ( Fig. 1 ). Usually, two loads of the linear stapler are needed as the goal is to have the pouch 10 to 12 cm in length. The pouch to anus anastomosis is created with a circular stapler ( Fig. 2 ). The anvil is placed in the pouch, secured with purse-string suture, and the handle is placed in the anus. The anastomosis is fashioned by firing the stapler. It is essential that there is excellent visibility in the pelvis when creating the anastomosis to ensure that the small bowel, bladder, vagina, etc. do not fall into the staple lines. There should be two complete “donuts” on the stapler, and the pouch should be inspected for bleeding by sigmoidoscopy and for air tightness by inflating air into the pouch and looking for air bubbles in the pelvis (saline irrigation is used to submerge the pouch from the abdominal side).

Most surgeons, when creating an IPAA, protect the pouch with a diverting loop ileostomy, created using more proximal small bowel brought up as a loop in the right lower quadrant. Although this does not prevent postoperative pelvic sepsis, it mitigates the severity as the fecal stream is diverted. The diverting loop ileostomy is closed in a separate operation about 3 months later. In most cases, this can simply be done with an incision around the ileostomy site, and the hospital stay is 1 to 2 nights. Rarely, more extensive dissection is needed, and a laparotomy is required. Before the ileostomy closure operation, the ileal pouch is interrogated with a Gastrografin enema to check for leaks at the staple lines and sometimes a flexible sigmoidoscopy to dilate the anus and inspect the mucosa.

Perioperative Management

Enhanced recovery protocols beginning in the days leading up to surgery and continuing through postoperative management should be used. Pain medication regimens should limit opioids and maximize nonopioid analgesia including regional analgesia as appropriate. For patients on high-dose, long-term steroids, a short course of steroid taper should be used to avoid manifestations of adrenal insufficiency. Surgical site infection prevention bundles including presurgery bathing with chlorhexidine, mechanical bowel preparation with oral antibiotics (elective surgery), preincisional prophylactic antibiotics (cefazolin and Flagyl, or as determined by the hospital), alcohol-based skin preparation in the operating room, and appropriate attention to sterile technique using a closing set when suturing on the fascia and skin should be employed. Early ambulation with deep venous thrombosis prophylaxis is essential to reduce the risk of clot formation as this patient population is at significantly increased risk. Catheter-associated urinary tract infection bundles should also be employed comprising of careful insertion by a trained provider and prewash with antiseptic soap; early removal either at the end of the surgical case or the following morning should also be integrated into the care.

Ileal Pouch Complications

Complications can be divided into immediate perioperative complications associated with pelvic surgery and longer-term complications more specific to the ileal pouch. Surgical risks include injury to surrounding structures, especially nerves associated with sexual and urinary function, infection related to leaking at staple lines leading to pelvic abscess and sepsis, bleeding and ileus, or early postoperative small bowel obstruction. Overall, the short-term complication rates are in the range of 10% to 15%. Postoperative management should also include monitoring for persistent frank blood in the stool consistent with intraluminal bleeding (although some bleeding is expected in the first few days), which may require endoscopy with inspection of the staple line. Hemodynamically unstable patients should be taken to the operating room. Early anastomotic leak will present with fever, tachycardia, leukocytosis, and pelvic abscess on cross-sectional imaging and is usually treated with a percutaneous drain, but sometimes it is very low in the pelvis and needs to be drained transanally in the operating room.

Pouch-specific issues include acute, recurrent, or chronic inflammation in the ileal pouch, termed pouchitis. This can occur in about half of patients and is generally treated with antibiotics, mesalamine, topical steroids, budesonide, or biologic agents. A small subset of patients may develop de novo Crohn’s disease after IPAA. Medically refractory pouchitis, especially secondary to de novo Crohn’s disease, may lead to pouch failure and necessitate end ileostomy and/or pouchectomy. Patients with inactive UC and no prior pelvic surgery have similar infertility rates to the general population. However, women should be counseled that IPAA has been reported to increase the infertility rate compared with medically managed patients, although laparoscopic approaches may preserve fertility.

Medical Therapy

Regardless of the underlying cause of toxic megacolon, immediate aggressive supportive management in an intensive care unit must be initiated.

There is no evidence to support the use of nasogastric tube decompression because it does not decompress the colon. Frequent patient repositioning has been described as a method of colon decompression based on the observation that gas tends to accumulate in the transverse colon if the patient remains in the prone position and may be redistributed to the distal colon and rectum with frequent repositioning. There is no strong evidence to support use of this technique; however, it is simple and may be attempted.

Complete bowel rest with adequate intravenous fluid replacement is required. Electrolyte abnormalities, especially hypokalemia, dehydration, and anemia can exacerbate colonic dysmotility and must be corrected aggressively. Any medications that affect colonic motility such as opiates, antimotility agents, and anticholinergics should be discontinued immediately. Prophylaxis for deep venous thrombosis and gastric ulcer should be administered. Broad-spectrum antibiotics were found to reduce the mortality from septic complications that result from associated bacteremia or colonic perforation and should be initiated, whereas any agent that may have led to C. difficile overgrowth should be discontinued. Frequent clinical assessment and close monitoring with physical examination, serial complete blood counts, electrolyte monitoring, and abdominal x-rays must be performed ( Fig. 2 ).

Surgical Therapy

Timing of surgical intervention is paramount in decreasing the morbidity and mortality of toxic megacolon and improving the patient’s overall outcome. Medical management has been reported to be effective and successful in 50% to 70% of patients with toxic megacolon. However, delay in surgical intervention carries a risk of developing abdominal complications such as colonic perforation and abdominal compartment syndrome, which increases the mortality rate from 2% to 50%.

The possible need for surgical intervention and the nature of surgery must be discussed with patients and their families on admission. All patients must be evaluated and marked by an enterostomal therapist who should mark the best site for an end ileostomy.

Surgery is absolutely indicated in the presence of progressive colonic dilatation, uncontrolled hemorrhage, development of complications such as free perforation, and with general clinical deterioration. This includes progressive sepsis with continued tachycardia, hypotension, or the need for presser agents to maintain blood pressure. Lack of improvement within 48 hours is also a relative indication for surgical intervention. It is better to proceed to the operating room sooner as opposed to later, and any of the previously mentioned findings should push the surgeon to operate.

Mechanical bowel preparation is contraindicated, and the surgery typically is performed through an open approach for two reasons. The significant colon dilatation and friability of the colonic wall do not allow for a workable space or graspable tissue and therefore preclude a laparoscopic approach. The patient is often unstable and needs significant resuscitation from sepsis, requiring a quick efficient operation. Patients with fulminant colitis who have not progressed to toxic megacolon are often managed with a laparoscopic total colectomy and end ileostomy. If the surgeon feels the colonic distention will not interfere with laparoscopic visibility, the patient is hemodynamically stable and not on any pressor medications, and colonic wall does not appear significantly thinned or necrotic, an attempt at a laparoscopic total colectomy is feasible.

The current surgical standard of care for patients with toxic megacolon who require surgery is total colectomy with end ileostomy. This removes the diseased colon and allows restoration of intestinal continuity after the patient has recovered. The rectum should not be resected at the time of this emergent operation despite how inflamed it may appear. The bowel is often fragile with a high likelihood of intraoperative perforation with manipulation resulting from the significant dilatation and inflammatory process, and thus it should be handled with extra care. During hepatic and splenic flexures mobilization, the colonic mesentery is divided close to the bowel wall to avoid damage to retroperitoneal structures.

The rectal stump is often just as severely inflamed and, therefore, difficult to manage. If the rectosigmoid junction appears too inflamed to hold staples or sutures, then the surgeon should leave a short segment of sigmoid colon to form a mucous fistula to decompress the remaining colon and rectum. In obese patients, the rectal stump may be brought through the inferior aspect of the midline fascial incision and left buried in the subcutaneous space. This will be removed at time of stoma reversal, and if the stump blows out, it allows for decompression through the wound as opposed to in the peritoneal cavity. If a rectal stump is left in the peritoneal cavity, it should be decompressed in the operating room with a rectal tube that is left in place to allow for further postoperative decompression and possible vancomycin enemas. Drains should be left on top of the stump. A rectal stump leak typically occurs 5 to 10 days after surgery; therefore, if a patient manifests signs of peritonitis 5 to 7 days after surgery after initially recovering well, the surgeon should have a high suspicion for rectal leak. Emergent return to the operating room with washout and drainage is necessary.

Postoperative care requires transferring the patient to an intensive care unit where all supportive measures are continued as needed. Preoperative antibiotics are discontinued within 24 hours, and intravenous steroids are tapered to a maintenance dose (equivalent of 10–20 mg of prednisone per day). On restoration of gastrointestinal motility, enteral feeding is given. The rectal tube is removed on the fifth to seventh postoperative day.

An alternative, less invasive, colon-preserving surgical approach for the treatment of CDAD is the formation of a loop ileostomy with antegrade vancomycin irrigation of the colon. In a case-controlled study, Neal et al. treated 42 patients with creation of a loop ileostomy after visual assessment of colon viability. Intraoperatively, colonic lavage with 8 L of warmed polyethylene glycol 3350/electrolyte solution was performed via the ileostomy and drained via rectal tube. Postoperatively, patients received antegrade vancomycin enema (500 mg in 500 mL of lactated Ringer’s every 8 hours for 10 days) via the efferent limb of the ileostomy. All patients received intravenous metronidazole (500 mg every 8 hour for 10 days). These patients were compared with matching historical controls treated with total colectomy and end ileostomy. In the study cohort, 35 (83%) cases were performed laparoscopically. The colon was preserved in 39 (93%) patients, and subsequent colectomy was required for continued sepsis in one patient and for abdominal compartment syndrome in two patients. When compared with a historical population, mortality was reduced from 50% to 19%.

Although this novel surgical approach may represent a less-invasive surgical treatment with promising outcomes, the results of this study are limited by the retrospective nature and lack of randomization that introduce a selection bias. Furthermore, there are no clear criteria to suggest which patient may benefit from this approach. Finally, the results were never reproduced by other investigators. There has been little written recently, but the technique may still be considered for those patients who are less severe. The 2015 practice parameters of the American Society of Colon and Rectal Surgeons for the management of C. difficile infection considered that the evidence for loop ileostomy formation in the management of toxic megacolon from C. difficile to be weak and strongly recommend the standard surgical approach in managing these patients, which is subtotal colectomy with end ileostomy. Loop ileostomy with antegrade colonic vancomycin lavage should not be considered in the severely septic patient requiring significant (presser or ventilatory) support.

Total Abdominal Colectomy

In a patient without free perforation, the preferred methods for TAC are laparoscopic mobilization of the abdominal colon and transection of the terminal ileum and rectosigmoid junction through a Pfannenstiel incision or intracorporeal transection at the rectosigmoid junction and extraction through the ileostomy site incision. There are several indications for TAC: (1) when more than two segments of colon are involved, with rectal sparing, and anastomosis is deemed unsafe; (2) when a patient presents in extremis with pancolitis, but a TPC is not indicated; and (3) when definitive diagnosis is not established, and indeterminate colitis is considered. The dissection for laparoscopic TAC begins with transection of the ileocolic pedicle and mobilizing the cecum away from the right iliac vessels at the right pelvic brim in a medial to lateral fashion and continues in a clockwise rotation to the hepatic flexure taking care to avoid injuring the duodenum. The gastrocolic ligament and any ligamentous attachments to the liver, spleen, and pancreas are divided to mobilize the transverse colon. The lateral attachments of the right colon to the lateral abdominal sidewall are divided last to finally release the right colon to the midline. The authors prefer to divide the omentum distal to the gastroepiploic arcade and remove it with the specimen. Many surgeons would try to preserve the omentum, but the difficulty in releasing the omentum from an inflamed transverse colon is likely to result in a colotomy and fecal spillage.

The splenic flexure is mobilized in an antegrade fashion from the right to the left, when feasible. When severely inflamed or in obese patients, it may be necessary to return to the splenic flexure in the retrograde fashion after partial mobilization of the left colon. Care must be taken to divide the base of the mesentery of the splenic flexure with sealing energy in case the arc of Riolan is a significant vessel and the branches of the inferior mesenteric vein (IMV) persist. All ligamentous attachments of the splenic flexure should then be dissected close to the colon to avoid injury to the splenic capsule. The left colon is mobilized by dividing the lateral attachments and freeing it off of the retroperitoneum starting at the left pelvic brim and dissecting medially, taking care to avoid injury to the left ureter. Ureteral stents placed at the induction of anesthesia can facilitate identification and protection of the ureters in a patient with severe inflammation in the descending colon and sigmoid regions. A medial approach to releasing the left colon and rectosigmoid junction allows avoidance of inflammatory attachments of the sigmoid and left colon to the critical structures at the pelvic brim. Working from soft normal dissection planes toward the diseased areas gives a better chance to complete the dissection and avoid injury to diseased and normal structures. Unlike TAC for malignancy, ligation of the vascular supply to the colon does not need to occur close to its origin in CC, and the mesentery can be ligated closer to the colon.

To date, the benefit of extended mesenteric resection for CD in reducing recurrence rate is not clearly established. However, the mesentery near the diseased bowel is often inflamed and thickened, so the soft, normal embryologic plane at the base of the mesentery may be the preferred dissection plane. Care must be taken to avoid significant bleeding from the thickened, friable mesentery during the transection of the vessels and at the point of transection of the colon. The rectum is identified at the distal sigmoid colon where the tenia coli “splay” out onto the anterior surface of the rectum. The peritoneal reflection is incised around the pelvic sidewalls and the proximal rectum is mobilized using the areolar tissue plane posterior to the rectum at the sacral promontory. The terminal ileum and the rectosigmoid junction are transected with a linear cutter stapler to control spillage after dividing the mesentery up to the bowel wall, either intracorporeally or through a small Pfannenstiel incision. The rectosigmoid junction is the preferred level of distal transection. This provides adequate rectal length for ileorectal anastomosis or creation of a mucus fistula and removes all colonic mucosa. Depending on the clinical scenario either an end ileostomy or ileorectal anastomosis is performed using either hand-sewn or stapled technique.

Patients who are restored to intestinal continuity with an ileorectal anastomosis often experience a period of rapid return of bowel function followed by a sudden decrease in bowel function, marked abdominal distension, and vomiting. This phenomenon, sometimes described as “ileorectal syndrome”, is caused by exposure of the terminal ileum to a high back pressure from the rectal vault. Drainage of rectal contents and relief of build-up of pressure in the ileum using an in-dwelling large catheter (24–34F) in the rectum can alleviate this ileal response to perceived obstruction caused by normal rectal pressures withholding stool from evacuations until a steady bowel function returns.

There are certain factors that need to be considered when deciding between ileorectal anastomosis and end ileostomy. The rectum and the perianal region must be examined carefully to make sure they are free of stricturing or fistulizing disease before committing to ileorectal anastomosis. Adequate sphincter resting tone and maximal squeeze pressures are required to prevent incontinence of liquid stool. The presence of fistulotomy or episiotomy scars should raise concern for postoperative inadequate control of liquid stool. The patient’s general condition such as nutritional status, weight loss, usage and dosage of steroidal agents, and smoking status should be reviewed to determine the feasibility of anastomosis. Opting for an end ileostomy confers a lower rate of recurrence of CD, especially in active smokers and patients with penetrating disease. The ileostomy and Hartmann stump of the rectum allows the surgeon to appreciate the natural history of the patient’s disease to determine whether an ileorectal anastomosis is possible in the future. A Brook ileostomy should be performed in the acute setting, in cases of indeterminate colitis, and when the rectum is involved. Management of the rectal stump remains controversial. It is the authors’ preferences to drain the stump with a rectal tube and leave a drain by the staple line for the duration of the hospital stay. The transected Hartmann rectal stump of an inflamed rectum is at risk for dehiscence of the upper staple line due to active disease and tissue friability. Other surgeons bring the stump to the incision and either suture it to the fascia or open it as a formal mucus fistula. These two options require a longer stump that may not be feasible with sigmoid involvement or in the obese patient.

Total Proctocolectomy

If two or more segments of colon are involved, and if associated perianal fistulizing disease is present, TPC with end ileostomy should be performed. Any presence of visible dysplasia not amenable for complete endoscopic removal, multifocal dysplasia, dysplasia in the surrounding flat mucosa, or carcinoma in the setting of pancolitis should also warrant TPC and end ileostomy. This is based on the observation that more than a third of patients who undergo colectomy for dysplasia are found to have multifocal dysplasia. In addition, 14% to 40% of patients who undergo colectomy for carcinoma in CC eventually develop metachronous cancer. The proctectomy portion of TPC proceeds after the abdominal portion as described earlier. Typically, the pelvic dissection follows the total mesorectal excision (TME) plane performed for rectal cancer surgery. This plane allows for decreased blood loss especially in the presence of inflamed mesorectum. Using electrocautery, the loose avascular areolar tissue of the retrorectal space is dissected to mobilize the rectum with the mesorectum intact. Once the posterior dissection is complete to the levator ani, the lateral attachments and the anterior Denonvilliers’ fascia/rectovaginal septum are dissected to the levator ani to completely mobilize the mesorectum. Extra care must be taken not to mistake the pelvic parietal fascia for the fascia propria of the rectum because the loose avascular areolar tissue between presacral fascia and pelvic parietal fascia can look identical to the one present in the retrorectal space. Surgeons often realize this mistake mid-dissection and, in an attempt to return to the correct retrorectal space, transect the hypogastric nerve embedded within the pelvic parietal fascia. A helpful hint is that if median sacral vessels running on the sacral periosteum are visualized, the dissection plane is already in a posterior plane deep to the desired plane anterior to the pelvic parietal fascia. One technique to reduce potential pelvic nerve injuries is to perform close rectal dissection (CRD). In this technique, the dissection is performed close to the rectal muscle wall within the mesorectum. This minimizes the risk of injury to the hypogastric nerves, the pelvic splanchnic nerves, and the inferior hypogastric plexus.

When ileal pouch-anal anastomosis (IPAA) for benign disease was randomized to CRD and TME, the CRD group suffered significantly fewer severe complications and improved quality of life. However, dissection through the mesorectal tissue often results in bleeding and is understandably associated with longer operating time (approximately 30 minutes). Once the rectum is completely mobilized intraabdominally as close to the anal canal as possible, the transperineal portion of the procedure is begun. Intersphincteric dissection for the completion proctectomy is preferred, whenever possible. The dissection is begun at the anal verge in the palpable intersphincteric groove with a circumferential incision into the space between the internal and external sphincters. The autonomic internal sphincter circular fibers do not twitch when touched with electrocautery. The somatic external sphincter fibers that encircle the internal sphincter fibers do twitch. The longitudinal rectal muscle fibers run at right angles to the circular fibers in the intersphincteric space and guide the dissection cephalad to the level of the puborectalis muscle. Preserving the well-vascularized external sphincter reduces the size of the perineal wound, allows better pelvic closure and healing, and reduces the risk of injury to the vagina/prostate and neurovascular bundle. Notwithstanding, extra care must be taken during anterior dissection to avoid injury to the vagina or the prostatic capsule. Frequent palpation of the posterior vaginal wall or the bladder catheter in the perineal and prostatic urethra helps to maintain orientation in the correct dissection plane. The dissection progresses circumferentially in a cephalad direction, and the levator ani muscles are finally separated from the rectum at the puborectalis sling to join with the dissection plane from the intraabdominal portion of the procedure. Once the rectum is removed, a drain is left in place in the pelvis through the abdominal wall or perineum. The levator ani, the external sphincter, and the ischiorectal fat are approximated in layers across the midline, but the subcutaneous tissue and skin are left open. This serves the purpose of draining the wound as well as leaving an opening that cosmetically resembles an anal orifice. The drain is typically removed in two weeks if drainage is minimal.

Restorative Proctocolectomy with Ileal Pouch Anal Anastomosis

There is a rare, select patient group with isolated CC without small bowel or perianal involvement who may be candidates for IPAA. If the diagnosis of CD is made before IPAA, pouch failure rate is 15%. If the patient is able to keep the pouch, functional outcomes and quality of life are similar between IPAA for CD and UC.

Minimally Invasive Surgery

Adaptation of laparoscopic surgery for CD has been rather unhurried in the surgical community compared with other arenas of abdominopelvic surgery. This is because the disease involves chronically inflamed bowel with friable and thickened mesentery that makes laparoscopic surgery particularly challenging. The initial randomized and observational studies comparing the outcomes of laparoscopic colectomy to open surgery have been promising. Similar to comparative studies for other colorectal disorders, laparoscopic colectomy showed decreased morbidity, decreased blood loss, faster return of bowel function, shorter hospital stays, and, in some cases, decreased costs. Furthermore, laparoscopic surgery allows specimen extraction through a Pfannenstiel incision, which affords decreased incisional hernia rate and pain ( Fig. 2 ). Fistulizing disease warrants a special mention as it adds another layer of complexity. So far, comparative observational studies have shown that although operating time, conversion rate to open surgery, and rate of stoma creation are all increased, overall morbidity rate remains the same between laparoscopic surgeries for fistulizing and nonfistulizing disease. Individual surgeon’s skill and comfort level should dictate if laparoscopic surgery is feasible in these cases. The use of hand-assisted laparoscopic surgery is an intermediate step between open operation and totally laparoscopic operations. The experienced hand, inserted through an airtight seal in the Pfannenstiel incision, can facilitate dissection by finding planes, identifying structures, encircling vessels bluntly, and guiding the incision by feel to speed the operation, thus reducing stress and risk and achieving the same outcomes as a pure laparoscopic procedure.

Robotic Surgery

Advantages of robotic surgery including intracorporeal anastomosis, smaller incision, and minimal manipulation of the bowel generally apply to CD. Robotic surgery is associated with a median of 2-day shorter length of stay and lower 30-day complication rate compared with open surgery. When robotic TAC for CC was compared with laparoscopy, no differences were noted including complications. Evidence in favor of robotic surgery in the management of CD is still in development.

Clinical Risk Factors for CDI

Several risk factors for contracting CDI have been identified. The most widely recognized and modifiable risk factor for CDI is antibiotic use; CDI can occur up to 3 months after antibiotic discontinuation. Antibiotics result in a disruption of the balanced normal colonic microbiota allowing pathogenic C. difficile bacteria to multiply and cause disease. While clindamycin was the first antibiotic to be associated with CDI, many other antibiotics have since been implicated. Antibiotic resistance patterns of C. difficile have also been found to be correlated to virulence. Another important risk factor for CDI is advanced age. Furthermore, immunosuppression, inflammatory bowel disease (IBD), gastrointestinal surgery, and length of hospitalization have all been associated with increased risk of CDI. Special attention needs to be paid to patients with IBD, as disease exacerbation can mimic C. difficile colitis. Although some epidemiologic studies have implicated gastric acid suppression as a risk factor, this association was not consistently found after adjusting for confounding factors and is most likely to be the result of patient illness and hospital length of stay.

Endoscopy

Pseudomembranes are a characteristic endoscopic feature of CDI that appear as raised white and yellow plaques and consist of toxin-induced ulcers with inflammatory cells and mucous ( Fig. 1 ). Confirmatory endoscopy with flexible or rigid sigmoidoscopy is not necessary; however, it is often performed to exclude other causes of colitis such as cytomegalovirus infection, graft-versus-host disease, IBD exacerbation, or ischemic colitis. Endoscopic confirmation has also been used in cases where a decision on surgical management needs to be expediently made and the situation does not allow waiting for confirmatory laboratory testing.

Imaging

Abdominal imaging can aid in the diagnosis of colitis and identify complications requiring operative intervention. Rarely, complications such as free air may also be seen. Classically, plain films were used to assess for “thumb printing” secondary to submucosal edema or toxic megacolon with colonic distention. Nowadays, an infused computed tomography (CT) scan of the abdomen and pelvis is the preferred imaging modality to assess the degree, extent, and complications of the colitis. Typical findings in severe or fulminant disease include pancolitis with significant colonic thickening and ascites ( Fig. 2A ). If gastrointestinal contrast is given, it can be seen trapped between the edematous haustral folds (accordion sign) ( Fig. 2B ). Evidence of complications such as bowel perforation, toxic megacolon, and ischemia can also be seen on CT.

Total Abdominal Colectomy with End Ileostomy

An open total abdominal colectomy (TAC) with an end ileostomy remains the gold standard operation for patients with fulminant C. difficile colitis (FCDC) requiring surgery and is the operation to which all others are compared. Outcomes after segmental colectomies for the treatment of FCDC have been shown to be inferior to TAC, and thus segmental colectomy is not recommended even if the colitis appears to be limited to a part of the colon on CT imaging. Upon entry into the abdominal cavity, usually profuse ascites is encountered. The colon usually appears dilated and edematous but otherwise has a normal serosal surface, as this is a mucosal disease. The distal extent of the resection is at the rectosigmoid junction, where the rectum is transected and stapled; however, if the rectosigmoid appears too friable and there is heightened concern for rectal stump blowout, the surgeon can consider a more proximal transection to allow delivery of a distal stapled end of more proximal sigmoid as a mucous fistula. It is our preference to place a Malecot rectal catheter in the rectal stump for the first few postoperative days to allow decompression while healing. Postoperatively, patients should remain in a monitored setting until their vital functions are stable without the supportive measures offered in the intensive care unit and until their systemic inflammatory response syndrome (SIRS) starts improving. Postoperative length of stay is often prolonged by the patient’s comorbidities, and rapid recovery is limited by the severity of the multiorgan system involvement. After recovery, ileorectal anastomosis can be performed if the patient has returned to a functional baseline. This usually occurs starting at 3 to 6 months postoperatively. Given the significant postoperative morbidity associated with a colectomy for severe CDI, many patients do not reach a level of fitness suitable to endure another extensive operation for restoration of gastrointestinal continuity with an ileorectal anastomosis. In the literature, most patients who undergo a TAC do not eventually have restoration of gastrointestinal continuity.

Colonic Lavage and Diverting Loop Ileostomy

The creation of a diverting loop ileostomy (DLI) with colonic lavage has been advocated as a less-invasive alternative to TAC in this critically ill-patient population. In 2011, Neil et al. described this approach, which consists of the creation of a DLI with colonic lavage with warm polyethylene glycol solution and postoperative antegrade installation of vancomycin flashes by the ileostomy ( Fig. 3 ). In their single-institution, single-surgeon series, the authors compared 42 patients who underwent surgery for FCDC with 42 historical patients who had undergone TAC. The authors observed a decreased 30-day postoperative mortality for patients who underwent a DLI compared with TAC. In addition to the survival benefit, the authors demonstrated increased ileostomy closure rates at six months. A minority of patients in the DLI group required conversion to a TAC either due to the development of abdominal compartment syndrome or for failure of improvement. Since the first description of this novel procedure, few studies have compared it to TAC. There remains a lack of high-quality prospective data comparing these two operations given the difficulty in conducting such studies in the setting of a disease associated with high mortality in the emergency setting. A recent meta-analysis of 733 patients with DLI and 2950 patients with TAC found no difference in postoperative morbidity or mortality but found higher gastrointestinal restoration rates for patients with DLI.

Thus, while no recommendations can be made on which patients would best benefit from DLI vs. TAC, we believe patients with severe disease early in their disease course, who do not have any complications associated with their colitis necessitating a TAC (perforation, ischemia, or toxic megacolon), can be offered a DLI with colonic lavage. However, one must be cautious that patients need close follow-up as the diseased colon is still in situ, and thus there is a longer time to resolution of SIRS. Typically, patients may take up to a few days to a week in this SIRS state before improving. Tables 3 and 4 summarize the current evidence and the advantages and disadvantages of each operation.

Theoretically, the creation of a DLI is relatively simple; however, there are a few technical challenges associated with fulminant disease state and with performing the colonic lavage. We summarized the steps of the operation in Box 2 and at the following link https://www.youtube.com/watch?v=1VMQrEI6jro&t=26s . Furthermore, comorbidities such as elevated BMI may be challenging and may be overcome with the creation of an end loop ileostomy.

History and Physical Examination

Prompt evaluation and diagnosis beginning with a focused history and physical examination should occur in patients presenting with signs and symptoms of a large bowel obstruction. Obtaining a careful history of the development of symptoms can often cue surgeons to the most likely diagnosis. Patients may report a rapid or slow progression of their symptoms depending on the etiology. Recent orthopedic or gynecologic procedures are commonly associated with the development of colonic pseudo-obstruction. A family or personal history of colonic neoplasms, diverticular disease, or inflammatory bowel disease, as well as findings on previous colonoscopy (if performed) should be ascertained as this helps narrow the diagnosis. A review of current medications may indicate prescription medication-induced constipation but equally importantly can provide an overview of the patient’s overall underlying health status and comorbid conditions.

The physical examination classically reveals a tympanitic and distended abdomen. On occasion, a mass can be palpated through the abdominal wall in thin patients. Focal tenderness on examination may suggest ischemia or localized perforation, whereas diffuse tenderness is concerning for peritonitis. A digital rectal examination is an important part of the exam and should be performed on all patients to rule out fecal impaction, foreign body, or anorectal malignancy as the cause. In elderly patients and/or those with severe comorbid medical problems, it is important to ascertain goals of care, especially when advanced malignancy is suspected.

Imaging

Because of ease in accessibility, upright and supine abdominal radiographs are often the first images obtained. For the diagnosis of large bowel obstruction, plain films have a sensitivity and specificity of 84% and 72%, respectively. Importantly, they can help rule out an abdominal disaster such as pneumatosis coli or pneumoperitoneum, which in the right clinical context may obviate additional imaging. Cecal distension of 9 to 12 cm on plain abdominal film is concerning for impending perforation. In the setting of an incompetent ileocecal valve, reflux of contents back into the small intestine may reflect as air-fluid levels of the small bowel with distension. When colonic volvulus is the cause of large bowel obstruction, plain films can confirm the diagnosis. The classic findings of a sigmoid volvulus are seen in about two-thirds of patients and are commonly described as the “bent inner tube” sign or an “omega loop.” In the case of cecal volvulus, this classically presents as the “coffee bean” sign; however, it is only seen radiographically in less than 20% of the patients.

Contrast enemas (CEs) were once the gold standard in the diagnosis of large bowel obstruction. However, because these tests are labor intensive and require additional time, CEs are not readily accessible and are underutilized. CEs have a 96% sensitivity and a 98% specificity for diagnosing large bowel obstruction, compared to the 84% and 72%, respectively, of plain abdominal films. Classic finding is a “bird’s beak” deformity at the site of a volvulus or an “apple core lesion” at the site of an obstructing cancer. CE can also provide additional details such as the length, width, and tortuosity of the narrowing that may be helpful when intraluminal stents are being considered. In cases of colonic pseudo-obstruction, contrast will freely flow without evidence of transition point. Additionally, in the setting of fecal impaction, contrast may be therapeutic.

Computed tomography (CT) has become the preferred imaging modality in the evaluation of a patient with signs and symptoms of a large bowel obstruction. CT is much more readily accessible than CE and has largely supplanted CE as the diagnostic modality of choice. CT confirms the diagnosis of large bowel obstruction with almost 100% sensitivity and 90% specificity; it also allows multiplanar reconstruction that further facilitates the definitive etiology of large bowel obstruction. Finally, CT may have a substantial impact on the clinical management of a large bowel obstruction by demonstrating signs of intestinal ischemia, early pneumatosis, or pneumoperitoneum leading to earlier interventions.

Initial Management

In concert with the initial history and physical, laboratory assessment should include serum chemistry and electrolytes, complete blood count, and lactate level. Hypovolemia and electrolyte imbalances are common and should prompt aggressive resuscitation with accurate monitoring of intake and output with a urinary catheter. Decompression with a nasogastric tube should be performed early. If surgery is a consideration, preoperative antibiotics and stoma marking should occur as an ostomy is frequently required.

Surgical Management

The optimal surgical management and approach, either laparoscopic or open, will vary according to the degree of obstruction, the underlying etiology of large bowel obstruction, as well as the clinical condition of the patient. Broadly, the surgical management of large bowel obstructions can be guided by the urgency of decompression, emergent or nonemergent.

Colonic Lavage

In select patients, the use of an on-table colonic lavage may permit a single-stage surgery in the setting of a left-sided large bowel obstruction. Following resection of the lesion, the colon should be fully mobilized at both hepatic and splenic flexures to facilitate irrigation and allow descending colon to extend beyond the abdominal cavity. Next, an appendectomy is performed, and a catheter is passed into the cecum and secured with a purse-string suture. This catheter is attached to a large bag of warmed saline and elevated on a pole. If the cecum is thinned, an alternative is to insert the catheter into the terminal ileum and secure with a purse-string suture. The staple line at the distal segment of colon is opened and a generous length of sterile corrugated tubing is placed into the lumen of the descending colon. The tubing is secured in place with umbilical tape or a purse string and then draped off the table into a basin. Three to six liters of warmed saline is then flushed through the colon. This is continued until the effluent clears ( Fig. 1 ). The catheter and tubing are removed, and the site of the appendectomy is closed. Before the anastomosis, the colon is inspected for injuries that may have occurred during the lavage. The anastomosis is then performed in the standard fashion, either end-to-end or side-to-side if there is a large bowel size discrepancy. A modified version of this method uses a Y-shaped connector ( Fig. 2 ). One limb allows for retrograde infusion of saline through the descending colon and the other is attached to drainage tubing. This modification is appealing as it obviates the need for the appendectomy or cecostomy. In a study by Jung and colleagues, 171 patients with an obstructing left-sided lesion received intraoperative colonic lavage with primary anastomosis. Compared with elective, nonobstructed patients during the same interval, anastomotic leakage and wound infection were not significantly different.

Endoscopic Stenting

In the past decade, endoscopic management of obstructing large bowel lesions has gained significant attention. Much of the literature is on stenting of obstructing left-side lesions, and although reports of right-sided lesions exist, the indication is less clear. In the appropriately selected patient, endoscopic stents can be tremendously beneficial. Indications for stent placement include palliation of an inoperable obstructing lesion (e.g., stage IV colorectal cancer) and as a temporizing “bridge” to definitive therapy in a patient with a curable or potentially curable lesion. The ability to stent a curable or potentially curable lesion affords time for colonic decompression, medical optimization, endoscopic evaluation for synchronous lesions, and increases the likelihood of a single-stage operation. Contraindications to stent placement include any of the previously discussed indications for emergent surgery, an abscess/infection closely associated with the lesion, short and tethered colon, and a lesion less than 5 cm from the anal verge.

Perioperative antibiotic coverage is unnecessary for stent placement. Gentle tap water enemas should be used to evacuate stool distal to the lesion. If an oral bowel preparation is desired, it may be attempted only if the obstruction is partial and the patient is closely monitored for the development of new or worsening symptoms. Colonoscopic evaluation of the lesion must be done with the utmost care; forceful attempts to traverse beyond the lesion are strictly avoided. Perforation is the most feared complication of stent placement. To mitigate the procedural risk of perforation, insufflation with carbon dioxide is preferred over room air because of the dramatically faster clearance time. The most common stents used in the United States are uncovered, self-expanding metal stents (SEM). Through-the-scope (TTS) and over-the-wire, also referred to as non-TTS, are the two conventional approaches to stent placement. TTS is usually the first-line approach ( Fig. 3 ). The TTS system requires a colonoscope equipped with a working channel to pass the guidewire and stent. The scope is advanced and parked in an area immediately distal to the lesion. Contrast is administered and the lesion assessed with fluoroscopy. The guidewire is then advanced safely beyond the lesion followed by the stent (Seldinger’s technique). Endoscopy and fluoroscopy confirm the correct location of the wire and the stent. Most TTS systems encourage a proximal and distal stent overlap of 2 cm. For longer lesions, additional stents can be placed in series. If assessment of the lesion shows anatomy unfavorable for TTS (e.g., available size of the stents), the procedure is converted to over-the-wire. With the guidewire fixed, the colonoscope is withdrawn entirely. The appropriate stent is selected and passed directly over the wire into position using fluoroscopy. Fluoroscopic or postprocedural abdominal films are obtained to confirm the typical stent appearance of a narrowed or waisted midportion with proximal and distal flaring. The flaring represents adequate overlap into normal, low-resistance lumen. To reduce development of rapid restenosis, the intraluminal diameter at the midportion of the stent should be at least 24 mm. Balloon dilation should not be attempted because of significant risk of perforation. If imaging does not demonstrate flaring at one or both ends of the stent, additional stenting is likely necessary and typically done in an end-to-end fashion. Patients should expect gradual improvement of symptoms over 3 to 5 days as the stents reach maximal expansion and the colon decompresses. For descending colon and beyond, patients are advised to consume a low-residue, low-fiber diet along with daily laxatives (e.g., polyethylene glycol) to promote soft stools that are unlikely to become impacted at the stent. It is important that if definitive therapy is planned, it should be done within 7 to 14 days following placement of the stent. Patients who receive stenting for palliation and the anticipated duration greater than 2 weeks have a significantly increased risk of stent complications, primarily perforation. Multidisciplinary discussion should weigh the possibility of surgical palliation in this high-risk population. Current literature reports successful stent placement for acute large bowel obstruction between 70% and 90%. In a pooled analysis by Sebastian et al., 25% of the 1198 patients who underwent stent placement for obstruction developed a complication. Most common complications include stent migration, reobstruction, and perforation. The most serious complication is perforation and occurs in 4% to 5% of patients. Intrinsic factors that may increase the risk of stent-related perforation include longer segment of obstruction (median length of 64 mm), benign etiology, and extraluminal origin.

Sigmoid Volvulus

Volvulus, from the Latin, volvere , means to roll. The classic patient with a sigmoid volvulus presents with colicky lower abdominal pain and obstipation. The demographic profile most affected by sigmoid volvulus is a black male older than 70 years with significant comorbidities. The two primary goals for management of sigmoid volvulus are to relieve the obstruction and prevent recurrence. The gold standard in the management of uncomplicated sigmoid volvulus is endoscopic detorsion, gross inspection to ensure viability of the colon, and placement of a drainage catheter (successful in up to 70%–90% of patients). Endoscopic reduction converts an emergency situation into an elective one and allows preparation of bowel and patient prior to definitive surgery. Failure of endoscopic reduction and/or presence of bowel ischemia is an indication for emergent resection. Primary anastomosis in this setting is an ongoing controversy and dependent of clinical picture of the patient. When endoscopic reduction is successful, definitive elective operation is recommended based on the high rate of recurrence; most studies cite a rate in the 50% to 80% range. Atamanalp and colleagues published data from a single-center review of 686 patients. They found morbidity and mortality of 35% and 16% for emergent surgery for recurrent sigmoid volvulus and 12.5% and 0% for elective surgery, respectively. Some suggest performing the definitive surgery as early as the index admission. Regardless of timing, the approach can be either open or minimally invasive. The redundant colon and narrowed mesentery leading to sigmoid volvulus results in an anatomical configuration that facilitates sigmoid resection with minimal difficulty. The gold standard is resection with primary anastomosis. For isolated sigmoid volvulus and the elective sigmoid colectomy, the recurrence rates are very low.

Cecal Volvulus or Bascule

The second most common site of colonic volvulus is the cecum ( Fig. 4 ). In patients with cecal volvulus, there is a female predominance, and typically patients are in the second and third decade of life, younger than those presenting with sigmoid volvulus. Presentation is similar to small bowel obstruction with abdominal distension, nausea, and vomiting; however, this can vary. There are three types of cecal volvulus:

• 1

  Axial cecal volvulus: A twist of the intestines in which the affected cecum remains in the right lower quadrant.

• 2

  Loop cecal volvulus: The cecum and terminal ileum are twisted in the axial plane and the affected cecum typically lies in the left upper quadrant.

• 3

  Cecal bascule: A redundant cecum folds in the sagittal plane onto itself and the proximal ascending colon leaving the affected cecum within the right upper quadrant.

All three types necessitate either an acquired or congenital hypermobile cecum and ascending colon. Types 1 and 2 are the most common, accounting for roughly 80% of cecal volvuli. Unlike types 1 and 2, type 3 does not exhibit torsion. Patients who present with type 3 typically have a much more insidious presentation. Endoscopic management is not recommended for cecal volvulus or bascule because of a low rate of successful detorsion, and colonic ischemia can be missed in up to 25% of patients. For the patient presenting with a high probability of cecal volvulus, the operation of choice is an exploratory laparotomy. Severe ischemia, necrosis, or perforation occurs in up to 44% of patients with cecal volvulus; if present, mortality rates are equally as high. Management of the patient with nonviable cecum is resection and creation of end ileostomy, with consideration for mucous fistula. If the cecum is viable or with patchy ischemia, there is less consensus on the appropriate management. Nonresectional options include detorsion with cecopexy and cecostomy. Widely variable rates of recurrence, morbidity, and mortality have been demonstrated, although there is a paucity of recent data that compares these options and with respect to viable versus nonviable bowel. Distillation of the current data favors ileocecectomy with primary anastomosis for patients with acute cecal volvulus, even when bowel appears viable. Laparoscopic approach is an acceptable option in stable patients with limited bowel distension if performed by an experienced surgeon.

Acute Colonic Pseudo-Obstruction

Acute colonic pseudo-obstruction (ACPO) is also referred to as Ogilvie’s syndrome in homage to British surgeon Sir Heneage Ogilvie who in 1948 identified two patients who presented with large bowel distension without an identifiable lesion. This syndrome is most encountered in the hospitalized, elderly male patient. Hospitalization is notably unrelated to the presenting symptoms rather for unrelated surgical procedure (most commonly involving pelvic dissection) or traumatic bony injury. Additional predisposing factors include severe electrolyte disturbances, certain medications, and acute deconditioning. Presentation is consistent with other etiologies of large bowel obstruction, including nausea, vomiting, and persistent abdominal pain. A significant portion of these patients will continue to pass loose stool. Focal peritonitis confined to the right lower quadrant may be a warning sign of impending perforation because of the profound cecal distension. These findings should encourage expeditious intervention. Perforation at the time of presentation occurs in about 15% of patients and often is associated with abdominal tenderness, cecal diameter greater than 12 cm, fever, and leukocytosis. Abdominal plain films are the best initial imaging study, although findings are nonspecific. Second-line imaging has traditionally been with water-soluble CE. Unfamiliarity with the technique coupled with the risk of perforation makes this option less favorable. The gold standard imaging modality is CT; findings include diffuse colonic distension, possible transition point near splenic flexure, and, importantly, no evidence of a mechanical obstruction. Nonoperative management of ACPO is successful in more than two-thirds of patients. This consists of aggressive fluid resuscitation, repletion of serum electrolytes as necessary, cessation of possible offending medications (e.g., opioids, anticholinergics), and bowel rest. The use of nasogastric and rectal tubes for decompression may also encourage the passage of flatus. These principles of nonoperative management are continued for up to 72 hours. During this period, it is essential to monitor the patient with the use of serial imaging and physical examination.

Failure to improve over this period necessitates the next step in the algorithm, neostigmine. Neostigmine increases the availability of acetylcholine through its antiacetylcholinesterase mechanism. In the colon, additional acetylcholine results in improved contractility and generalized motility. Before administration, the patient should be transferred to a unit with continuous cardiopulmonary monitoring and the ability to administer atropine, glycopyrrolate, or both. Neostigmine is contraindicated in patients in whom there is suspicion for ischemia or perforation, severe acute bronchospasm, poorly controlled cardiac dysrhythmia, or pregnancy. With the patient connected to continuous monitoring, the first dose of neostigmine of 2 to 5 mg is given intravenously over 1 to 5 minutes. Success is achieved with passage of flatus, stool, or decreased abdominal distension. Patients are observed over the next 80 minutes. Atropine and glycopyrrolate should be readily available if there is development of bradycardia or bronchospasm, respectively. Neostigmine is successful at treating ACPO in more than 90% of cases. For patients who are partial responders or nonresponders after one dose, a second can be administered with high rates of success. For those who fail to respond to neostigmine, the next step in management is endoscopic decompression. Geller et al. reviewed 50 patients with ACPO treated with colonoscopic decompression and found clinical success in 95% following a single intervention, 18% needed at least one additional colonoscopy; for patients who did not receive a decompression tube at the time of the procedure, clinical success was only achieved in 25%. Regarding technical considerations, insufflation should be minimized and preferably with carbon dioxide. The scope should be advanced into the right colon. A decompression tube is strongly recommended and should originate from the right colon; however, randomized controlled trial data are lacking to support the use of decompression tubes. Evidence does, however, support the use of polyethylene glycol solution after endoscopy and neostigmine to lower recurrence rate. The endoscopist should remove as much gas as possible during withdrawal of the scope. If endoscopic decompression is not possible or unsuccessful, percutaneous cecostomy can be used with variable success. When all these interventions have been unsuccessful, operative management is indicated. The surgery is dictated by the intraoperative findings. A minilaparotomy may be enough to assess the viability of the colon. If there is no evidence of perforation or ischemia, a tube cecostomy or surgical cecostomy may be sufficient. When ischemia is identified, the affected region should be resected, including subtotal colectomy if indicated. Primary anastomosis is not recommended but rather the creation of end colostomy with or without mucous fistula.