Arden M. Morris
Presentation
A 28-year-old woman presents to the emergency department with complaints of recurrent, severe upper abdominal pain for the third time in 1 month. Prior to her recurrent symptoms of crampy abdominal pain, nausea, and vomiting, the patient had a normal 8-month intrauterine pregnancy and was nonobese and otherwise healthy except for longstanding constipation.
Presentation
Colonic vovulus is a rare cause of bowel obstruction in the developed world, with an estimated annual incidence of about 3/10,000 in the United States. Although volvulus is unusual, it is the most common cause of bowel obstruction in pregnant women and the third leading cause of colonic obstruction after cancer and diverticulitis. Patients present with symptoms of excruciating abdominal pain out of proportion to the clinical examination, absence of flatus, and an empty rectal vault. Often, minimal distension is present during early volvulus that increases dramatically over time.
The mechanical etiology of volvulus is axial rotation of the colon, resulting in a closed loop obstruction. Axial rotation usually arises in one of two alternative mechanisms. First, in the case of a congenitally unfixed or partially unfixed colon, any portion of the colon—particularly the cecum—is at risk. During peristalsis, an unfixed ileocecal area on a narrow mesentery can twist, resulting in initial right lower-quadrant pain and symptoms of small bowel obstruction with minimal distension. Second, in an acquired fashion, the sigmoid colon may elongate due to chronic constipation and then twist on the relatively narrow mesentery. Major risk factors for sigmoid volvulus are advanced age, neurologic and psychiatric disease, lifelong high-fiber diet, and other causes of chronic constipation or elevated intraluminal pressure. Patients with compromised communication, such as those with dementia, previous stroke, or psychiatric disorders, are particularly susceptible to a delayed diagnosis.
If colonic volvulus does not self-reduce or otherwise resolve, the increased luminal pressure, thinning colon wall, and compromised venous outflow will lead over time to ischemic compromise of the bowel wall with necrosis and perforation.
Differential Diagnosis
Colonic obstruction should be considered cancer until proven otherwise. Other items in the differential diagnosis are pseudo-obstruction, constipation, obstipation, diverticulitis, intussusception, external compression by adhesions, and external compression by an extraluminal mass. Rarely, patients may present with late symptoms of volvulus including colonic ischemia, necrosis, and perforation. Therefore, the differential diagnosis of late volvulus includes the conditions listed above as well as mesenteric ischemia.
Workup
The diagnosis of volvulus is usually based on history and physical examination and confirmed radiologically. Volvulus pain can be intermittent, with initial self-reducing episodes of partial torsion. The pain tends to be diffuse and crampy in nature, which may differ from the constant pain of obstructing rectal cancer. Most patients present with symptoms several times before they are diagnosed. Important history and physical exam findings include elderly, infirm, or chronically institutionalized patients, the presence of longstanding constipation, vague recurrent discomfort, signs of obstruction, and no stool in the rectal vault on digital examination. The exception to this general picture is the young, otherwise healthy pregnant woman with intermittent bouts of increasing abdominal pain and obstructive symptoms during progression into the third trimester.
Laboratory tests are not diagnostic but may indicate secondary sequelae of obstruction such as electrolyte abnormalities, nonanion gap acidosis, and an elevated white blood count. High lactic acid levels are rare and indicate a more advanced disease process.
Radiologic imaging is the key to the diagnosis, starting with a flat and upright abdominal x-ray. The classic appearance of sigmoid volvulus on x-ray is a “bent inner tube sign,” with an inverted, distended sigmoid loop absent the normal Haustral folds and pointing toward the right upper quadrant (Figure 1). If the patient is stable and there is any doubt about the diagnosis based on regular abdominal x-ray, a water-soluble radio-opaque enema may be performed. Barium is contraindicated in this setting due to risk of perforation. The classic finding on contrast enema of a “bird’s beak” appearance to the bowel lumen (Figure 2) should result in resuscitation, colonic decompression, and elective operation. If a contrast enema is nondiagnostic or not feasible, a CT scan with intravenous contrast should be performed. Skipping the contrast enema and going immediately to a CT scan is also a reasonable practice. The CT scan can help to identify alternative diagnoses and can demonstrate the sine qua non “swirl sign” indicating a torsed mesentery. Rigid or flexible lower endoscopy can play either a diagnostic or more often a therapeutic role for the patient with volvulus.
FIGURE 1 • Abdominal x-ray displaying a distended sigmoid in an inverted U, directed superiorly, with loss of haustral folds and proximal distended bowel. (Image supplied courtesy of Charles O. Finne.)
FIGURE 2 • Radio-opaque enema displaying the classic “bird’s beak” of narrowed lumen at the distal site of torsion, without contrast (A) and with contrast (B).
Diagnosis and Treatment
If free intraperitoneal air is present on abdominal radiographs, no further studies are needed. The patient and family should be warned that this is an ominous sign and, after obtaining informed consent, the patient should be resuscitated with normal saline or lactated ringers and electrolyte repletion before urgently performing an open exploratory celiotomy with Hartmann procedure and peritoneal irrigation.
Presentation Continued
In the scenario described above, the patient was clinically stable and her diagnosis remained in doubt despite a suggestive abdominal x-ray (Figure 3). The abdominal x-rays showed a severely distended colon and an empty rectum but no characteristic signs. Therefore, lower endoscopy was performed, revealing a combination of spiral narrowing of the sigmoid colon with associated mucosal erythema, edema, and ulcerations (Figure 4). The endoscopist was able to advance the scope beyond this segment without significant effort, revealing proximal colonic dilation.
FIGURE 3 • Abdominal radiograph of patient displaying distended sigmoid colon with loss of Haustral markings and proximal distension, as well as a third-trimester fetus.
FIGURE 4 • Endoscopic appearance of the sigmoid mucosa with a swirl pattern confirming volvulus and ulcerations and erythema consistent with ischemia.
If no free intraperitoneal air is present and the patient is clinically stable, she can be resuscitated and the colon decompressed preferably with a flexible or rigid sigmoidoscope. Particularly in frail or elderly patients, rigid sigmoidoscope is preferable due to lower risk or colonic perforation and the ability to pass a rectal tube through the scope lumen to continue proximal decompression for several days. After supportive care and resolution of symptoms, an elective operation should be undertaken within 3 months as up to 70% of cases will recur without an operation.
In the case of an unsuccessful attempt at decompression, the patient should be taken urgently to the operating room for an exploratory celiotomy and sigmoid resection. The decision to perform an anastomosis versus colostomy will depend upon the presence of ischemia, stool spillage, and the general health of the patient.
Although sigmoid volvulus is the most common cause of colon obstruction during pregnancy, fewer than 100 cases have been reported in the literature. The consensus based upon these is that, in the absence of peritonitis, nonoperative decompression is preferred in the first trimester, sigmoid colectomy based upon these cases is preferred in the second trimester, and nonoperative treatment is again preferred in the third trimester until delivery. After delivery, a sigmoid colectomy is recommended.
Surgical Approach
As noted above, if the patient is unstable or has free intraperitoneal air, she should be resuscitated and taken to the operating room urgently for an open exploration (Table 1). Laparoscopic exploration is not judicious during an urgent operation for volvulus given the extensive dilated bowel and negligible working space. A laparoscopic or an open approach could be used for a patient who has undergone successful endoscopic decompression.
TABLE 1. Key Technical Steps and Potential Pitfalls in Operating for Sigmoid Volvulus
For sigmoid volvulus, the appropriate operation is a sigmoid colectomy. For cecal volvulus, the definitive operation is a right colectomy with primary anastomosis. In both cases, intraoperative judgment should inform the decision for an ostomy versus primary anastomosis. Cecopexy to the right lower quadrant also has been described as a way to speed the operation and limit anastomotic complications. However, this advantage may be undone when placing suture in a distended, thinned cecal wall. Additionally, cecopexy for volvulus has historically been associated with a high recurrence rate. Placement of a cecostomy tube is also described for extremely frail patients.1Advantages are the avoidance of an abdominal wound and tethering of the cecum that theoretically prevents recurrent torsion.
For the most part, the key technical steps in operating urgently for sigmoid volvulus also apply to a resection for cecal volvulus. Fist, a midline laparotomy and full abdominal exploration are performed with the goal of identification of potential areas of bowel ischemia or other causes of obstruction. Warm saline-soaked sponges are applied to any dusky bowel. Identify areas of torsed bowel as well as areas of ischemia extending beyond the obvious torsion. Before detorsing, identify appropriate proximal and distal sites for current or future anastomosis. Divide the mesentery prior to detorsing in order to avoid exposing the circulation to accumulated cytokines or bacteria in the ischemic segment. Divide the bowel proximally and distally and remove the specimen from the field.
Intraoperative judgment regarding whether to anastomose the bowel or to create an end ostomy and mucus fistula depends upon the patient’s cardiovascular function, nutritional status, and absence of bowel necrosis or gross contamination. As well, the remaining bowel must be healthy-appearing and the ends must come together without tension. If an anastomosis is performed, it should be scrutinized for adequate perfusion, patency, and if possible undergo a leak test prior to closing the abdomen. A leak test can be performed for a sigmoid resection but is problematic for a right colectomy. A straightforward approach to the leak test is to fill the pelvis with sterile saline, gently compress the bowel proximal to the anastomosis, and insufflate the rectum with air using a rigid sigmoidoscope. The presence of bubbles indicates a leak. Other options for leak test include instillation of betadine or indigo carmine in the rectum and a search for discoloration of surrounding lap sponges applied to the anastomosis.
Special Intraoperative Considerations
Occasionally, a severely demented or otherwise non-communicating patient with severe colonic distension and radiographic free air will undergo celiotomy and no evidence of perforation can be identified. If the bowel appears pink and viable and no evidence of a perforation site, sucus, purulence, or other spilled bowel contents can be identified, resection is not warranted. If the colon can be decompressed endoscopically, this may be advantageous but will likely be temporary.
Postoperative Management
Patients who have undergone a bowel resection for colonic volvulus should be managed expectantly with intravenous hydration, electrolyte repletion, and bowel rest until the return of peristalsis. Intravenous nutrition should be considered if the patient is initially malnourished or if more than a week passes without oral intake. Routine postcolectomy care is appropriate in the absence of clinical instability. For patients with an end ileostomy, waiting at least 6 to 12 weeks before performing an ostomy closure is prudent.
Case Conclusion
After decompression of the colon, patient A.B. was initially taken to the operating room for a transverse loop colostomy by the emergency surgery service. Six weeks later, she had a normal spontaneous vaginal delivery of a healthy baby. At 6 weeks postpartum, she underwent an uneventful closure of the transverse colostomy closure and resection of approximately 18 inches of sigmoid colon with a primary anastomosis through a small Pfannensteil incision by the colorectal surgery service.
TAKE HOME POINTS
· Colonic volvulus, an axial rotation of the colon resulting in a closed loop obstruction, can occur at any nonfixed portion of the colon, most commonly in the sigmoid colon and cecum.
· Conditions such as chronic constipation or treatment for neurologic or psychiatric conditions are associated with chronically increased intraluminal pressure and ultimately elongation of the sigmoid colon, resulting in greater risk of volvulus.
· Colonic volvulus is typically diagnosed based on radiographic studies, including upright abdominal radiograph (“bent inner tube sign” or “coffee bean sign”), radio-opaque enema (“bird’s beak”), or computed tomography (“swirl sign”).
· The first line of treatment for volvulus in a stable patient is endoscopic decompression and placement of a decompressing rectal tube, followed by supportive hydration and electrolyte correction.
· Patients who cannot be treated successfully with endoscopic decompression or who exhibit worsening clinical signs should be taken to the operating room for an open procedure.
· Prior to intraoperative detorsion of the volvulus, the mesentery should be divided to prevent circulation of inflammatory cytokines or septicemia.
· Even among stable, successfully decompressed patients, an elective laparoscopic or open sigmoidectomy is recommended due to recurrence rates ranging from 30% to 70%.
SUGGESTED READINGS
Alshawi JS. Recurrent sigmoid volvulus in pregnancy: report of a case and review of the literature. Dis Colon Rectum. 2005;48(9):1811–1813.
Ballantyne GH, Brandner MD, Beart RW Jr, et al. Volvulus of the colon. Incidence and mortality. Ann Surg. 1985;202(1):83–92.
Renzulli P, Maurer CA, Netzer P, et al. Preoperative colonoscopic derotation is beneficial in acute colonic volvulus. Dig Surg. 2002;19(3):223–229.