28 Volvulus of the Colon
Abstract
This chapter discusses volvulus of the colon, specifically the incidence, etiology, clinical presentation, diagnosis, and treatment of sigmoid volvulus, ileosigmoid knotting, cecal volvulus, volvulus of the transverse colon, and splenic flexure volvulus.
28.1 Introduction
Volvulus refers to a torsion or twist of an organ on a pedicle. It can involve the stomach, spleen, gallbladder, small bowel, right colon, transverse colon, splenic flexure, or sigmoid colon. 1 Volvulus of the large bowel results from the colon’s twisting on its mesentery, producing symptoms by either narrowing of the bowel lumen, strangulation of the blood vessels, or both.
Widespread differences based on geographic and epidemiologic factors are seen in the distribution of volvulus. Overall in the United States, the sigmoid colon accounts for 43 to 71% of the cases of colonic volvulus. Most of the remaining cases involve the cecum and the right colon; volvulus of the transverse colon or splenic flexure is relatively rare, accounting for only 2 to 5% and 0 to 2%, respectively. 2 In Olmstead County, Minnesota, during the period 1960 through 1980, the age-adjusted incidences of sigmoid volvulus and cecal volvulus were 1.67 and 1.20 per 100,000 persons per year, respectively. 3 In an unusual report from the high-altitude area of the Bolivian and Peruvian Andes at 13,000 feet above sea level, sigmoid volvulus accounted for 79% of all intestinal obstruction. The reason is not clear but may be related to the increased gas volume in the bowel because of high altitude. 4
28.2 Sigmoid Volvulus
28.2.1 Incidence and Epidemiology
In the United States, sigmoid volvulus is an infrequent cause of intestinal obstruction and occurs much less often than carcinoma or diverticulitis as a cause of colonic obstruction. In an extensive review, Ballantyne 5 found that only 3.4% of 4,766 cases of intestinal obstruction and 9.6% of 1,206 cases of colonic obstruction in the United States were caused by sigmoid volvulus. The highest reported worldwide incidence appeared in a study from northern Iran by Scott, 6 who found that sigmoid volvulus was the cause of 85% of colonic obstructions. Johnson 7 reported 13 cases of sigmoid volvulus in a series of 24 bowel obstructions from Ethiopia. 7 Increased frequency of sigmoid volvulus in Pakistan, India, Brazil, and Eastern Europe also has been reported. 5 Although volvulus does occur with increased frequency in the Soviet Union, 5 the previously reported data from the 1920s, 8 in which more than 50% of cases of bowel obstruction were caused by volvulus, may not be accurate today because of changing epidemiologic and dietary factors.
Among reported cases of sigmoid volvulus from the United States, Ballantyne 5 has isolated the following epidemiologic factors:
Sex. Sigmoid volvulus is more common in men, occurring in 63.7% of men in a collected review of 571 patients. Bruusgaard 9 had previously attributed this finding to the wider female pelvis and more relaxed abdominal musculature, which afford an early volvulus a better chance of spontaneous reduction.
Age. Analysis of data from 43 studies reveals that the average age at which sigmoid volvulus occurs in English-speaking countries is 60 to 65 years, although it tends to occur 15 to 20 years earlier in other parts of the world. Other data suggest a trend toward earlier onset in English-speaking countries as well. 10
Race. Racial differences have been noted in many U.S. studies on sigmoid volvulus. Review of 221 patients in 10 series revealed that two-thirds (146) were black, one-third (74) were white, and 1 was Hispanic.
Residence. Review of nine U.S. studies revealed that 45.1% of 244 patients were admitted to the hospital from another institution. Of all patients, 54.9% came from private homes, 32.4% from mental institutions, and 12.7% from nursing homes.
Typically, then, the sigmoid volvulus patient in the United States is male, black, elderly, and may be institutionalized. In other parts of the world, the typical patient is also male but is younger and living at home, probably in a rural area.
28.2.2 Etiology
In order for it to twist on itself, the sigmoid colon must be long and floppy, with a narrow mesenteric root. It can be congenital or acquired, particularly after previous abdominal surgery causing scar at the root of the sigmoid mesentery.
The concept of the etiology of intestinal volvulus is based on the fact that bowel when distended becomes elongated. By direct measurement, the antimesenteric border of the bowel increased its length by 30%, whereas the mesenteric border increased by only 10%. 11 As the bowel distends, it rotates in response to the need to accommodate this disproportionate increase in the length of its antimesenteric border. Perry 11 created a model using thin latex rubber tubing gathered up on its “mesenteric” border by a stiffer adhesive rubber strip to limit the elongation of this border. A latex rubber sheet was used to produce a deep “mesentery” (▶ Fig. 28.1). Inflation of the “bowel” produced a 180-degree volvulus (▶ Fig. 28.2). The same result follows the inflation of an isolated segment of cadaver ileum in which the mesentery has been refashioned and sutured to make it deep with a narrow base (▶ Fig. 28.3). An example of this concept in vivo can be observed. In Afghanistan, for example, during the feast of Ramadan, the incidence of this type of volvulus rises sharply from bloated intestine. 12 “Red gut,” a disease of sheep grazing alfalfa (Lucerne), is thought to be the result of volvulus associated with bowel gas distention. 13
It becomes clear that in order to have a volvulus, the bowel has to be distended with air to float. Colon that is full of stool cannot float and twist but by its weight may twist on itself and is not a true volvulus. In fact, the gush-out of “stool” on reducing the sigmoid volvulus is an exudate from obstruction, not the loaded stool from constipation.
A large number of precipitating or associated factors have been implicated in the genesis of sigmoid volvulus, including lead poisoning, 14 vitamin B deficiency, 14 adhesions, 15 gout, 15 Hirschsprung’s disease, 16 megacolon and diabetes, 17 Parkinson’s disease and other neurologic disorders, 17 Chagas’ disease, 18 stroke, 19 sprue, 20 ischemic colitis, 21 peptic ulcer, 22 tuberculosis, 22 cardiovascular disease, 23 hypokalemia, 24 pregnancy, 25 and excessive enemas. 26
28.2.3 Pathogenesis
In a patient with a sigmoid volvulus, the twist of the sigmoid may be in a clockwise or counterclockwise direction, but it is usually counterclockwise around the axis of the mesocolon with varying degrees of rotation (▶ Fig. 28.4). For significant obstruction to occur, the torsion must be at least 180 degrees. Torsion less than this is generally asymptomatic and can be considered physiologic.
The obstruction produced is a closed-loop type of mechanical obstruction that may be simple or strangulated. In the early stages of obstruction, peristalsis forces gas and fluid into the closed loop to remain trapped as the twist acts as a check valve to prevent release. Occasionally, some trapped air and gas are forced from the loop so that the diarrheal stools may occur. With simple obstruction, the bowel wall generally remains viable for a few days, largely because the sigmoid colon can tolerate more intraluminal pressure than other parts of the intestinal tract before signs of vascular compromise appear. Eventually strangulation will occur, with occlusion of the veins developing first, followed by occlusion of the arteries, mesocolic thrombosis, and infarction. Necrosis usually occurs first at the site of torsion but may include the entire loop.
In the acute fulminating variant of this disease, gangrene may occur much more rapidly because of a sudden, tight compression of the mesenteric vessels compounded by a rapid distention of the bowel lumen.
28.2.4 Clinical Presentation
Although a chronic, painless variant of sigmoid volvulus has been described, 27 the condition should be viewed as an acute disease. Hinshaw and Carter 28 have distinguished between two distinct clinical presentations of acute sigmoid volvulus depending on the rapidity of the twisting mesentery.
In the “acute fulminating type,” the patient is generally younger, the onset of symptoms is sudden, and the course is rapid. Generally, there is little history of previous episodes, and symptoms include early vomiting, diffuse abdominal pain and tenderness, marked prostration, and the early appearance of gangrene. Distention may be minimal, and findings often are not distinctive. In its classic form, the acute fulminating variety of sigmoid volvulus produces no distinctive diagnostic signs except for the clinical picture of an acute abdominal catastrophe; the actual diagnosis is made at celiotomy.
The second type, or “subacute progressive type,” is the more common presentation. The patient is generally older, the onset more gradual, and the early course more benign. There is often a history of previous attacks and chronic constipation. Vomiting occurs late, pain is minimal, and signs of peritonitis are usually not present. Abdominal distention is generally extreme in this form, and radiographic findings are usually diagnostic.
28.2.5 Diagnosis
In the acute fulminating type, the diagnosis of acute peritonitis is evident, immediate celiotomy is mandatory, and specific diagnostic measures are generally not indicated. In the more common subacute progressive type, the diagnosis can be strongly suspected by the history and physical examination. In addition to a history of chronic constipation and possibly previous episodes, there is a recent history of gradual onset of cramping, lower abdominal pain, and progressive distention. Usually, there is obstipation and absence of flatus, although there may be occasional diarrheal stools. Vomiting is uncommon as an early symptom. Marked abdominal distention and tympany are the most striking physical findings. Bowel sounds may be hyperactive or hypoactive but generally are not absent.
The diagnosis is usually confirmed by X-ray examination. A plain film of the abdomen classically shows a massively distended single loop of bowel on the right or left side of the abdomen with both ends in the pelvis and the bow near the diaphragm (“bent inner tube sign”; ▶ Fig. 28.5). Fluid levels may be seen in the sigmoid loop with little difference of levels in the upright position. The degree of distention of the proximal colon and small bowel on the right side of the abdomen varies. A Gastrografin enema study reveals a pathognomonic finding of the Gastrografin column, ending sharply at the level of the site of torsion (“bird’s beak” or “ace of spades” deformity; ▶ Fig. 28.6). Burrell et al 29 evaluated the plain abdominal radiographs in patients with sigmoid volvulus. Three signs, the apex of the loop under the left hemidiaphragm, inferior convergence on the left, and the left flank overlap sign, are 100% specific as well as being highly sensitive. The sign that is least specific is a distended ahaustral sigmoid loop and an air:fluid ratio greater than 2:1.
In approximately 30 to 40% of the cases, plain films can be equivocal. The transverse colon or small bowel distention can superimpose on the sigmoid loops; the two limbs may overlap, deviate laterally, or be oriented in an anteroposterior plane; the sigmoid can be fluid filled; or a dilated, redundant transverse colon or a closed-loop small bowel obstruction may mimic sigmoid volvulus. 30 , 31 In these cases, computed tomography (CT) is the preferred confirmatory test. 32 It is noninvasive, easily obtainable, accurate, and has the advantage of identification of incidental pathology that may be missed by studies. The sigmoid afferent and efferent loops have a radial distribution around a low-attenuating adipose area (the twisted mesocolon) with a soft-tissue center (the point of torsion). Engorged and stretched vessels converge toward the center. This feature is described as the “whirl sign” (▶ Fig. 28.7). CT scan can also identify signs of strangulation. 33 In the study by Swenson, 34 the positive diagnostic yield of CT was 89%.
28.2.6 Treatment
Management of Nonstrangulated Sigmoid Volvulus
The goals of therapy in nonstrangulated sigmoid volvulus are directed at relief of acute torsion and prevention of recurrences. Ideally, the volvulus should be derotated and the colon decompressed. A few days later, after a full colonic preparation, sigmoid resection is performed. However, there are other lesser procedures to prevent recurrences such as tube sigmoid colostomy, 35 mesosigmoidoplasty, 36 and sigmoid colopexy. 37
Rigid Sigmoidoscopic Decompression
In 1947, Bruusgaard 9 described his experience with nonoperative reduction by sigmoidoscopy and passage of a rectal tube into the obstructed loop. The procedure was performed on 136 cases and was successful 123 times for a 90% success rate; 4 deaths occurred, with a mortality rate of 2.9%. In the 1950s and 1960s, greater experience was gained with the nonoperative method. Several larger series with equally impressive results were reported. Drapanas and Stewart 38 reported successful decompression with rectal intubation in 82 of 98 cases (84% success) with a 1.2% mortality rate; Wuepper et al 19 were successful with this method in 44 of 54 cases, and had a mortality rate of 5.5%; and Shepherd 39 was successful in 78 of 89 cases, with a 3.4% mortality rate. In addition, in 1973 Arnold and Nance 23 had a 77% success rate in 114 cases.
Comparative figures for survival with operative detorsion have consistently yielded higher mortality rates than nonoperative reduction. Hinshaw and Carter 28 reported a 22% mortality rate for operative detorsion in 18 patients. Shepherd 39 reported a 16% mortality rate for 49 patients, and Sutcliffe 40 reported 2 deaths in 19 patients (11% mortality rate). Gama et al 18 and Sharpton and Cheek 41 have reported mortality rates as low as 5 and 8%, respectively, and Gulati et al 42 have reported a 35% mortality rate for 34 patients.
Nonoperative decompression thus has become the preferred initial treatment for nonstrangulated sigmoid volvulus. This approach, however, should not be used in three situations: (1) when there are clinical signs of nonviable bowel, (2) if a trial of sigmoidoscopy has failed to achieve immediate reduction, and (3) when volvulus repeatedly recurs. In these situations, it is safest to proceed with immediate celiotomy.
The technique of sigmoidoscopic decompression is as follows. Preparation of the patient for surgery is begun so that if the nonoperative technique fails, operative intervention will not be delayed. Preferably the patient is placed in the prone jackknife position because this position facilitates the decompression by allowing the colon to fall away. The lateral decubitus position is acceptable if the patient cannot tolerate the jackknife position. The rigid sigmoidoscope is carefully inserted until the site of torsion is seen, and the mucosa is inspected carefully for signs of ischemia or necrosis. If the mucosa appears intact, a soft, well-lubricated 40- to 60-cm rectal tube is passed gently beyond the site of torsion until there is an immediate return of gas and stool from the obstructed loop. The rectal tube can be passed through the sigmoidoscope or along the side of the sigmoidoscope. The tube is then secured to the perianal skin and is left in place for at least 48 hours (▶ Fig. 28.8). Reports showed a wide range of success rates in sigmoidoscopic decompression between 38 and 100%. 2 , 37 , 43 , 44 , 45 , 46 When decompression is unsuccessful, strangulation of the sigmoid volvulus must be suspected, or the volvulus is beyond reach of the sigmoidoscope. Flexible sigmoidoscopy and colonoscopy are now widely used and have largely replaced the rigid sigmoidoscope.
Colonoscopic and Flexible Sigmoidoscopic Decompression
Despite the fact that many failures of sigmoidoscopic decompression of a sigmoid volvulus are related to gangrenous changes at the site of torsion, a significant number of failures occur because the rigid 25-cm sigmoidoscope does not reach the site of obstruction.
In 1976, Ghazi et al 47 presented the first case of colonoscopic decompression of sigmoid volvulus with the site of obstruction measured at 105 cm from the insertion of the colonoscope. Subsequent favorable reports with both the full-length colonoscope 48 , 49 , 50 and the flexible sigmoidoscope 51 have appeared. A review of 25 cases of sigmoid volvulus revealed that 24 of the cases were safely decompressed colonoscopically, with the only failure occurring when the colonoscope was deliberately withdrawn when cyanotic mucosa was identified 80 cm from the anus. 49 Renzulli et al 52 reported a success rate of only 58% in a small series of 12 patients. In a review of 189 patients with sigmoid volvulus from Veterans Affairs hospitals, using endoscopy (rigid sigmoidoscopy, flexible sigmoidoscopy, or endoscopy), the success rate was 81%. 53 Colonoscopic and flexible sigmoidoscopic decompression differs from rigid sigmoidoscopic decompression in that the colonoscope itself is passed through the site of torsion, often with gentle air insufflation as the scope is passed beyond the obstruction. Some authors have attached an external suction device to the biopsy portion of the colonoscope to facilitate removal of liquid, stool, and debris from the unprepared colon. 54 Others have attached to the colonoscope a jejunostomy-type tube that is left as a decompressing stent that can be passed as far proximally as the cecum. 55 A rectal tube can be passed after the volvulus has been reduced by passing the tube alongside with the flexible scope in place or after it has been withdrawn.
The precautions taken for rigid sigmoidoscopic decompression also apply to colonoscopic and flexible sigmoidoscopic decompression. If reduction does not occur promptly, the procedure should be terminated in favor of surgery. The procedure should also be abandoned in the presence of bloody drainage or cyanotic mucosa.
Flexible endoscopy is a sensitive means of diagnosing both acute sigmoid volvulus and intermittent sigmoid volvulus. Twisting spirals of mucosa are seen if the volvulus is still present. Even if the volvulus has spontaneously reduced, the mucosa at the site of volvulus demonstrates discrete and localized signs of inflammation. In addition, the vascular markings are obscured and the mucosal folds are thickened. There may also be some granularity or friability. These findings are limited only to short segments of approximately 4 to 5 cm at both the rectosigmoid and the descending sigmoid junctions. 3
Surgical Management
Although the mortality rate of sigmoidoscopic deflation without further treatment is relatively low, at 5 to 8%, most deaths are the result of coexisting disease rather than a direct result of the procedure itself or complications related to the procedure. 56 The recurrence from sigmoidoscopic deflation alone is high, 40 to 70%. 2 , 39 , 44 With this high recurrence, it is obvious that further management is desirable. The mortality of surgery for sigmoid volvulus depends on whether the colon is gangrenous, and on the severity of intercurrent disease. Elective colon resection for sigmoid volvulus is most efficient. When properly performed, recurrence should not occur, although this complication has been reported. 39 , 46
Most authors have emphasized the need for elective resection in all patients who had an episode of sigmoid volvulus, although some have reserved elective resection for selected lower-risk patients. Shepherd 39 reported on 74 elective resections performed 5 to 8 days after conservative treatment, with a mortality rate of 2.8%. Even in patients who have been classified as higher risk, the elective mortality rate should be lower than the risk of death from complications of recurrent volvulus.
In a recent study by Yassaie et al, 57 31 patients with sigmoid volvulus who underwent successful endoscopic detorsion and no further interventions before discharge were evaluated. Recurrent sigmoid volvulus was diagnosed in 19 (61%) of these patients at a median of 31 days. Of these 19 patients, 7 underwent colectomy and 12 had repeat endoscopic detorsion alone, of whom 5 (48%) were diagnosed with a third episode of volvulus at a median interval of 5 months and 3 (25%) required emergent sigmoid colectomy. In a study by Swenson et al, 34 10 (48%) of 21 patients with sigmoid volvulus treated nonoperatively returned with recurrent volvulus at a median of 106 days (range 8–374 days) after discharge. Tan et al 58 observed recurrent sigmoid volvulus in 28 (61%) of 46 patients who were discharged after endoscopic reduction alone.
Sigmoid Colon Resection
For a nonstrangulated colon, sigmoid colon resection can be performed as an elective procedure a few days later, after a bowel preparation. If an urgent exploratory celiotomy is necessary, the left colon and rectum can be irrigated with povidone–iodine via a rectal tube. The mortality rate for sigmoid colon resection with primary anastomosis has been reported to be between 0 and 12.5%. 39 , 43 , 59 , 60 , 61 For gangrenous bowel, sigmoid resection with a colostomy and Hartmann’s procedure is the safest, although some authors perform an anastomosis. The operative mortality is between 0 and 38%. 39 , 43 , 59 , 60 , 61 , 62 Even without gangrenous colon, emergency sigmoid resection with primary anastomosis has a high anastomotic leak rate. 63
Much of the mortality associated with elective sigmoid resection after volvulus can be reduced by taking advantage of the unique anatomic features of the sigmoid in these patients. Because the sigmoid is long and freely movable, the mesosigmoid is also long, and the points of peritoneal fixation are close together, the redundant loop usually can be delivered out of the abdominal cavity through a limited incision (▶ Fig. 28.9). The peritoneum is entered through a short transverse incision made in the left lower quadrant, dividing through the left rectus muscle. The redundant loop is delivered, the mesocolon is divided to free a proximal and a distal end, and the anastomosis is made on the surface of the abdomen. The bowel is then dropped back into the peritoneal cavity and the incision is closed. In elderly debilitated patients, this procedure can often be performed with local anesthesia.
At operation, it is important to examine the entire abdomen to make certain that there is no volvulus at any other part. Simultaneous sigmoid and cecal volvulus is rare but has been reported. 64 An example of this condition can be seen in ▶ Fig. 28.10.
In the series reported by Grossmann et al, 53 178 of 228 (78%) patients underwent a colostomy, with 44% considered to be urgent. Evidence of ischemia was present in 86 of 178 cases (48%), and frank necrosis of the colon was observed in 59 of 178 cases (33%). Sigmoid resection was performed in 173 of 178 patients (97%): 107 of 173 patients (62%) had resection with colostomy; 66 of 173 patients (38%) had primary anastomosis; colostomy without sigmoid resection was performed in 2 of 178 patients (1%); and 3 of 178 patients (2%) underwent sigmoidopexy. There were no operative deaths. Twenty-five of 178 patients (14%) died within 30 days of surgery.
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