Large-Bowel Obstruction Treatment & Management

Surgical intervention is directed at relieving the obstruction.

A diverting transverse loop colostomy may be the least invasive procedure for a very ill patient with a left colonic obstruction. It permits relief of the obstruction and further resuscitation without compromising chances for a subsequent resection. A case report described the use of hand-assisted laparoscopy via the loop colostomy site for subsequent resection of the obstructing lesion.^[17]

A sigmoid colostomy without resection may be used in patients with a rectal obstruction that cannot be managed without a combined abdominoperineal approach. Cecostomy should not be performed, because the diversion is inadequate.

In younger patients without substantial comorbidity, some surgeons would consider primary anastomosis, rather than ileostomy, in the right colon, assuming no intraoperative hypotension, blood loss, or other complications are present.

If resection and proximal colostomy or ileostomy are performed, a mucous fistula is generally extracted from the distal end, unless the obstruction is rectosigmoid, in which case the distal end may be oversewn or stapled and left to drain transanally.

If the cause of the obstruction can be relieved nonsurgically, through procedures such as decompressing a volvulus, or if the obstruction is only partial, deferring surgery temporarily and supporting the patient while the large bowel is cleansed so that primary anastomosis may be performed more safely is preferable.

A slow preoperative mechanical bowel preparation is indicated for patients who have incomplete obstruction, provided the patient can tolerate it. Some authors prefer polyethylene glycol solutions, such as GO-LYTELY, because they avoid issues of fluid and electrolyte imbalance.^[18] The fluid should be administered slowly (rather than given in the standard manner of 1 gal over 4 h), and the patient should be observed for abdominal cramping and intolerance.

Carcinoma

In most patients, the obstructing lesion is resected. Because the colon has not been cleansed, anastomosis is often risky. After resection, most surgeons perform a proximal colostomy if the obstruction is on the left side or ileostomy if it is on the right side.

In patients with substantial comorbidity and surgical risk or in the presence of an unresectable tumor, a diverting proximal colostomy or ileostomy may be performed without resection.

Left vs right colon carcinoma

Surgical treatment of left colon carcinoma includes resection without primary anastomosis or resection with primary anastomosis and intraoperative lavage.^{[19, 20]} Endoscopically placed expandable metal stents can be used to relieve the large-bowel obstruction, thus allowing for a primary colorectal anastomosis.^[21]

Right colonic obstructions are treated with a right colectomy and a primary anastomosis between the ileum and the transverse colon. Patients with high-risk features for surgery (advanced age, complete obstruction, or severe comorbidities) may benefit from stent placement until patient can be optimized for a surgical procedure.^[22] Palliative colorectal stents are an option in patients who are poor surgical candidates or have advanced cancer.

Diverticulitis

Patients with persistent obstruction secondary to diverticular disease despite appropriate medical management are treated surgically. Surgical resection follows the same principles as the treatment of carcinomas. Elective colonic resection is offered to patients with recurrent disease.

Sigmoid vs cecal volvulus

Sigmoidoscopy with volvulus reduction is the procedure of choice for sigmoid volvuli.^[1] Second choice is sigmoid colectomy.

The primary treatment of cecal volvuli is also surgical. A cecopexy often needs to be performed to prevent recurrence. Second choice is colonoscopy, due to the high risk of colonic perforation.

Intussusception

Adult colonic intussusception is treated with primary colon resection without prior reduction.

Care after discharge following surgical management of large-bowel obstruction (LBO) focuses on surgical convalescence and, if relevant, the need to care for the disease that caused the obstruction. An obstructing colon cancer may require postoperative chemotherapy, depending on the stage of the disease. The patient who is chronically obstipated may need stool softeners.

Aggressive screening for colorectal cancer in individuals who are older than 50 years or who have a strong family history of colorectal cancer, as indicated by current guidelines, should reduce the future incidence of malignant colonic obstruction.

If the patient has received a colostomy or ileostomy, a decision regarding whether it is temporary or permanent may have been made at the time of discharge, depending on the patient's diagnosis, comorbidity, and postoperative convalescence.

Most patients who retain a rectum are, at least in principle, candidates for reanastomosis at a subsequent stage. Generally, it is performed 2-3 months after the initial operation. Careful counseling and assessment are required before proceeding with the second procedure.

Counseling is directed at the risks of the second procedure, because the patient must understand that this surgery is elective and that a colostomy or ileostomy is compatible with a reasonable lifestyle. Often, local ostomy support groups and meeting with other patients with ostomies are helpful at this time.

Patients who had stool incontinence before their first operation, those with substantial surgical risks, and patients with decreased mental status who are cared for in nursing homes may potentially be better off without a reanastomosis.

In addition, the remaining colon, both proximally and distally, must be evaluated radiographically or endoscopically to rule out synchronous colonic lesions, such as neoplasms, because the presence of the large-bowel obstruction prevented this from being performed before the first procedure.

Patients with an endoscopically reduced sigmoid volvulus should be offered elective surgical procedures, including sigmoid resection or fixation, because of the high risk of recurrence.

Initial therapy in patients with suspected large-bowel obstruction (LBO) includes volume resuscitation, appropriate preoperative antibiotics, gastric decompression, and timely surgical consultation.

Insert a nasogastric tube if the patient has been vomiting. The patient's intravascular volume is usually depleted, and early intravenous fluid (IVF) resuscitation with isotonic saline or Ringer lactate solution is necessary.

Further assessment and management may include the following:

• Anatomic and, if possible, pathologic characterization of the cause of the obstruction
• Bowel cleansing if the obstruction is incomplete
• Surgical relief of the obstruction

Obtain early consultation from a general surgeon. Surgical intervention is frequently indicated, depending on the cause of the obstruction.

Transfer to another facility is indicated if adequate surgical management or backup is not available. Before the transfer, the patient should be adequately hydrated and resuscitated.

Medical care of colonic obstruction is directed primarily at supporting the patient and treating any comorbid illnesses. This involves resuscitation, correction of fluid and electrolyte imbalances, and nasogastric decompression to temporarily treat the obstruction and to prevent vomiting and aspiration. Medications that slow colonic motility (eg, narcotics, anticholinergics) should be stopped, if possible.

Oral laxatives are contraindicated if large-bowel obstruction is suspected. If any evidence suggests simple constipation, patients should be managed with transrectal enemas. Tap water, isotonic sodium chloride solution, and a variety of other fluids may be used. In patients with renal insufficiency, the physician should be sensitive to the electrolyte content of the fluid.

If the patient’s pain is sufficiently severe to merit use of significant analgesics, peritonitis, rather than large-bowel obstruction, should be considered as the first diagnosis.

For a small subset of patients, in whom the obstruction is not only malignant but also reflects substantially disseminated or even inoperable disease, consideration of completely nonoperative palliative therapy within the context of a palliative care or hospice approach may be appropriate. This might include somatostatin therapy and may or may not include nasogastric decompression.^[13]

For acute colonic pseudo-obstruction (ACPO), or Ogilvie syndrome, underlying precipitant factors must be identified and corrected. If no perforation is present, pseudo-obstruction is treated with conservative management for the first 24 hours. This includes bowel rest, hydration, and management of underlying disorders.

Pharmacologic treatment of acute colonic pseudo-obstruction with neostigmine or colonoscopic decompression may be effective in cases that do not resolve with conservative management.^[14] Colonoscopic decompression may be successful in as many as 80% of patients with acute colonic pseudo-obstruction.^[8]

Surgical intervention for acute colonic pseudo-obstruction is associated with a high mortality and morbidity. This treatment is reserved for refractory cases or cases complicated by perforation.^[8]

Cleansing enemas

Perform cleansing enemas if obstipation is suspected rather than true large-bowel obstruction. These can also be performed to prepare the distal colon for endoscopic evaluation.

Endoscopic reduction of volvulus

Endoscopic reduction is indicated for sigmoid volvulus when peritoneal signs are absent, which would imply dead bowel or perforation. This procedure is also indicated when evidence of mucosal ischemia is not present upon endoscopy. An experienced person should perform the procedure.

Endoscopic reduction is not indicated for the less common cecal or transverse colon volvulus.

A rigid sigmoidoscope may be used if a flexible instrument is not available. The endoscopist must have sufficient experience with this technique.

Reduction of a volvulus does not imply cure. The sigmoid usually revolvulizes if definitive treatment is not carried out.

These patients are generally admitted to the hospital, subjected to mechanical bowel preparation, and managed surgically by sigmoid resection, unless contraindications are present.

Reduction of intussusception with barium enema

Barium enema for reduction of intussusception is useful and often successful in children in whom a pathologic leading point for the intussusception is unlikely. This procedure should be performed by an experienced radiologist, because the risk of perforation is significant.

In adults, typically a pathologic leading point for the intussusception is present. Success is far less likely, and patients still require surgery to deal with their pathology.

Endoscopic dilation and stenting of colonic obstruction

Endoscopic dilation and stenting of colonic obstruction is indicated for colonic near-total obstruction through which some small amount of lumen remains. The procedure may be palliative in a high-risk patient with an unresectable malignancy, accepting a risk of reobstruction of the stent, or preparatory to surgical resection.

In cases in which the stent is deployed before surgery, this procedure permits relief of the acute obstruction, resuscitation of the patient, and mechanical bowel preparation before a 1-stage colonic resection and reanastomosis, thus avoiding temporary or permanent colostomy.

Endoscopic dilation and stenting of colonic obstruction should be performed only by an endoscopist experienced in such procedures.

Surgical consultation and backup should be available, as the risk of perforation is increased during attempts at such procedures, with a potentially catastrophic result.

Although some experience with stenting has been positive,^[15] with some retrospective preference for the Ultraflex stent over the Wallstent because of ease of placement, a multicenter trial of endoscopic stenting using the Wallstent versus surgery for stage IV left-sided colorectal cancer was terminated early because of an unacceptably high incidence of perforation.^[16] Whether this finding reflects the technical aspects of the procedure in that study, the particular stent used, or a truly unacceptable incidence of this dangerous complication awaits further study.

Dietary considerations

Patients with complete large-bowel obstruction should receive nothing by mouth (NPO). Patients with a partial obstruction may tolerate minimal clear liquids, oral medications, and a gradual bowel preparation.