Sigmoid and Cecal Volvulus 

The term volvulus is derived from the Latin word volve, which means to twist. A colonic volvulus occurs when a part of the colon twists on its mesentery, resulting in acute, subacute, or chronic colonic obstruction. The image below illustrates cecal volvulus with associated small bowel obstruction.

More than 2500 years ago, Hippocrates noted that "the intestines tend to become sluggish and bloated with age." In his treatise "Diseases," he described the deflation of volvulus by "placement of a suppository 10 digits long" into the rectum. In 1859, in England, Gay again suggested this mode of deflating the volvulus, but it did not gain widespread acceptance until the middle of the next century. In 1841, von Rokitansky was the first to reference this condition in Western medicine. He described volvulus as a cause of intestinal strangulation. In 1898, von Zoege Manteuffel published an exhaustive description of colonic volvulus.

Prior to the 19th century, the management of patients with volvulus remained largely expectant. Gradually, as nonintervention became associated with a high mortality rate, early surgical treatment became a widely accepted practice. In 1883, Atherton first described open reduction of the volvulus at laparotomy. Simple detorsion was found to carry an unacceptably high recurrence rate, and attempts at plication of the mesentery and fixation of the sigmoid colon produced no significant improvement in outcome. The failure of sigmoidopexy was illustrated during re-exploration of the abdomen for recurrent volvulus, which often revealed little evidence of the attempted fixation.

By 1920, all 3 surgical approaches (ie, open detorsion and mesenteric plication, resection with colostomy, resection with anastomosis) were widely used for the surgical treatment of patients with sigmoid volvulus. Emergency resection carried a mortality rate of well over 50%. The Mikulicz operation (exteriorization of the sigmoid loop, resection, creation of a double barrel colostomy), Hartman procedure (resection of sigmoid loop, proximal colostomy, closure of distal rectum), and sigmoidopexy combined with partial resections were also attempted, with variable results.

In 1947, Bruusgaard described the technique of transanal deflation of the volvulus using sigmoidoscopy. This method of treatment was further supported by Drapanas and Stewart, who cited no mortality using this approach compared with the 50% mortality rate associated with emergent surgical treatment.^[1] Nonoperative detorsion as the only treatment was associated with a high recurrence rate. Elective resection after a few days of decompression of the colon was adopted and remains the current surgical treatment of patients with sigmoid volvulus.

von Rokitansky first described cecal volvulus in 1841, and, in 1899, Treves reported a process later designated by Weinstein as cecal bascule. The surgical treatment of patients with cecal volvulus paralleled that of those with sigmoid volvulus; prior to the early 19th century, expectant management was widely practiced. As experience accrued, surgical treatment became accepted. Detorsion and cecopexy were widely practiced, as was placement of cecostomy tubes. The high recurrence and complication rates led to the currently accepted procedure of right hemicolectomy for treatment of patients with cecal volvulus. Cecostomy is reserved for patients who are too debilitated to withstand resection.

Frequency

Colonic volvulus ranks after cancer and diverticulitis as a cause of large bowel obstruction in the United States. Colonic volvulus is responsible for approximately 5% of all cases of intestinal obstruction and 10-15% of all large bowel obstructions. In these populations, the most common site of large bowel torsion is the sigmoid colon (80%), followed by the cecum (15%), transverse colon (3%), and splenic flexure (2%).

In Western society, the average age of patients with sigmoid volvulus is in the eighth decade, and both sexes are equally affected. Various series have reported that 25-35% of all patients diagnosed with volvulus are admitted to an acute care facility from a neuropsychiatric care institution and 10-15% from a long-term nursing care facility.

Worldwide geographic variations in the incidence of sigmoid volvulus are well described. A much higher frequency is reported in Africa, Asia, and Middle Eastern, Eastern European, and South American countries. In all of these regions, the inhabitants consume a high-fiber diet, which is considered a predisposing factor for the development of sigmoid colon volvulus. In these endemic areas, the patients are younger and predominantly male.

In the volvulus belt of Africa and the Middle East, nearly 50% of large bowel obstructions are a result of volvulus, almost exclusively of the sigmoid colon. Cecal volvulus is much less common than sigmoid volvulus, accounting for 10-15% of all cases of volvulus and predominately affecting women in the sixth decade of life.

The presence of a long mesentery with a narrow base of fixation to the retroperitoneum and elongated, redundant bowel predisposes to the formation of volvulus. Any portion of the large bowel can develop a volvulus. However, volvulus is most common in the sigmoid colon because of the mesenteric anatomy. Less commonly, the right colon and terminal ileum (usually referred to as cecal or cecocolic volvulus) or the cecum alone (termed a cecal bascule) are the sites of volvulus. Rarely, the transverse colon or splenic flexure of the colon develops a volvulus.

Sigmoid volvulus may occur because of sigmoid elongation, resulting in a redundant loop. Most commonly, this is the result of chronic constipation and the progressive dilation and lengthening of the sigmoid colon and its mesentery.

Institutionalized patients with neuropsychiatric disorders often develop sigmoid volvulus. A higher incidence of the condition is observed in patients with Parkinson disease, multiple sclerosis, or spinal cord injury. Psychotropic drugs interfere with colonic motility and are etiologically implicated in the high incidence observed in patients in psychiatric institutes. Patients in nursing homes also commonly develop sigmoid volvulus. This association may be a manifestation of the prolonged recumbency and chronic constipation that patients in chronic care facilities experience. Not surprisingly, the excessive use of laxatives, cathartics, and enemas is highly associated with the development of sigmoid volvulus.

In developing countries, a high-fiber diet results in overloading of the sigmoid colon, which twists around its mesentery and results in volvulus. Megacolon, either congenital or acquired because of Chagas disease, predisposes to the development of sigmoid volvulus. In areas of South America where Chagas disease is endemic, the development of sigmoid volvulus in affected patients is reported to be as high as 30%.

The presence of a pelvic mass also increases the risk of developing sigmoid volvulus. The mass displaces the sigmoid colon sufficiently to result in torsion of the mesentery and a resultant volvulus. The association of pregnancy and large ovarian tumors with sigmoid volvulus is well known. In Western societies, as many as 45% of pregnant patients with intestinal obstruction have sigmoid volvulus.

Less common conditions resulting in sigmoid volvulus include postoperative adhesions, internal herniations, intussusceptions, omphalomesenteric abnormalities, intestinal malrotations, and carcinoma. A rare condition in patients with abnormally long mesenteries of the stomach, splenic flexure, and sigmoid colon has been described as traveling volvulus. The abnormal mesenteric fixation of intraperitoneal organs predisposes these patients to recurrent spontaneous torsion and detorsion.

Compared with sigmoid volvulus, which is usually an acquired condition, cecal volvulus is due to congenital incomplete dorsal mesenteric fixation of the cecum or ascending colon associated with an abnormally elongated mesentery distal to this area of absent mesentery. In autopsy studies, marked mobility of the right colon occurs in an estimated 15-20% of the population.

Cecal volvulus may be organoaxial (true cecal or cecocolic volvulus) or mesentericoaxial (cecal bascule).

The former involves the distal ileum and ascending colon twisting around each other, in much the same way as a sigmoid volvulus. Compared with sigmoid volvulus, in which the torsion is in a counterclockwise direction, cecal volvulus usually occurs in a clockwise direction. A cecal bascule involves the cecum folding in an axis at right angles to the mesentery.

Other anomalies that predispose to cecal volvulus include undescended right colon and previous surgical mobilization of the cecum, both permitting sufficient mobility for volvulus. Appendicitis, with resultant formation of adhesions, also predisposes to cecal volvulus.

As in sigmoid volvulus, a pelvic space-occupying lesion, such as a gravid uterus or an ovarian tumor, may precipitate an episode of cecal volvulus by altering the relative positions of the intra-abdominal organs. Gaseous dilation of sigmoid colon and cecum following colonoscopy has also been described as a cause of volvulus.

Chronic constipation in Western society and a high-fiber diet in developing nations lead to an overloaded sigmoid colonic loop. The weight of this loaded sigmoid colon makes it susceptible to torsion along the axis of the elongated mesentery. The presence of a gravid uterus or a large pelvic mass alters the relative positions of the intra-abdominal organs, also predisposing to formation of volvulus.

Because of subacute, repeated attacks of torsion, the base of the sigmoid mesocolon becomes foreshortened. The associated mild, chronic inflammation at the base of the mesentery and the 2 limbs of the sigmoid colon loop lead to the formation of adhesive tissue. This causes the sigmoid loop to become chronically fixed into a paddlelike configuration, which, in turn, predisposes to recurrence of the torsion (see the image below).

Incomplete cecal and ascending colonic fixation occurs because of a lack of embryologic development of the dorsal mesentery. The lack of development predisposes the patient to clockwise torsion of the cecum, terminal ileum, and ascending colon. Vascular compromise is common because of mesenteric torsion. In contrast, a cecal bascule occurs when the malfixed cecum folds anteriorly over the ascending colon. As no torsion of the ileocolic mesentery is present, vascular compromise of the cecum rarely occurs. Vascular compromise occurs more commonly in cases in which significant distension is present, which prevents the cecum from unfolding into its normal position. See the images below.

A complete volvulus leads to the development of a closed loop obstruction of the affected colonic segment. Increased dilation of the bowel loop compromises the vascular supply of the bowel, eventually leading to ischemic gangrene and bowel wall perforation.

The differential diagnosis includes an ileosigmoid knot, which is a rare condition. An ileosigmoid knot occurs when the ileum and sigmoid colon become entangled, creating a knot that results in vascular compromise of the bowel. The patient presents with acute onset of abdominal pain and rapidly developing shock.

Patients with volvulus are commonly elderly, debilitated, and bedridden. Often, the patient has a history of dementia or neuropsychiatric impairment. As a result, only a limited history is available.

More than 60-70% of patients present with acute symptoms; the remainder present with subacute or chronic symptoms. A history of chronic constipation is common. The patient may describe previous episodes of abdominal pain, distension, and obstipation suggestive of repeated, subclinical episodes of volvulus.

The presenting symptoms are similar, regardless of the anatomical site of the volvulus. Cramping abdominal pain, distention, obstipation, and constipation are present. With progressive obstruction, nausea and vomiting occur. The development of constant abdominal pain is ominous and indicates the development of a closed loop obstruction with significant intraluminal pressure. This, in turn, portends the development of ischemic gangrene and bowel wall perforation.

Abdominal distension is commonly massive and characteristically tympanitic over the gas-filled, thin-walled colon loop. Overlying or rebound tenderness raises the concern of peritonitis due to ischemic or perforated bowel. The patient may have a history of episodes of acute volvulus that spontaneously resolved; in such circumstances, marked abdominal distention with minimal tenderness may occur.

Depending on the extent of bowel ischemia or fecal peritonitis, signs of systemic toxicity may be apparent. Because of the massive abdominal distension, the patient may have respiratory and cardiovascular compromise.

The decisions regarding timing of surgery and type of surgical procedure depend on the patient's condition at the time of presentation.

In patients with no evidence of peritonitis or ischemic bowel, treatment is started with resuscitation and detorsion of the sigmoid volvulus. This is accomplished using a sigmoidoscope or colonoscope and concomitant rectal tube placement. The bowel is then prepared and surgery is undertaken electively during the same hospitalization. Inability to detorse the sigmoid volvulus via endoscope requires immediate surgical intervention. If the patient has evidence of peritonitis or ischemic bowel, emergent surgery is undertaken, and the operative procedure is chosen based on intraoperative findings.

Radiologic diagnoses of cecal volvulus or cecal bascule are also indications for surgical intervention, since the obstruction in these conditions cannot be reliably reduced with colonoscopy. This remains controversial, as increasing reports of successful detorsion of cecal volvulus suggest that, in patients who are stable, a single attempt at colonoscopic decompression is reasonable.

The embryonic right colon typically has a mesentery that eventually fuses to the parietal peritoneum, resulting in adherence to the posterior abdominal wall. Developmental variations in the degree of this fusion lead to differences in the mobility of the ascending colon and the cecum (see the image below). Hendrick, in a 1964 review of several cadaver studies, indicated that 10-25% of the general population has a propensity for cecal volvulus based on the length of the colonic mesentery.^[2] The long mesentery of the ascending colon results in a mobile cecum.

Two conditions must be present for the development of a cecal volvulus: an abnormally mobile segment of cecum and colon and a fixed point around which the mobile segment can twist. The second condition is created through normal ileocolic attachments, as well as through abnormal adhesions following surgery or appendicitis.

Jackson veil is an abnormal membrane that passes anterior to the ascending colon and permits the cecum to be mobile around the lower point of the fixation permitted by the membrane (see the image below).

The descending colon becomes the sigmoid colon at the level of the iliac crest. The mesosigmoid has variable attachments to the posterior body wall; the most common is attached diagonally downward toward the right side. Cadaver studies in the United States reported by Vaez-Zadeh in 1969 demonstrated the average length and breadth of the sigmoid mesentery as 7.9 cm and 5.6 cm, respectively.^[3] Comparatively, cadaver studies from the Middle East reported a mesenteric breadth of 15.2 cm. This racial difference may be developmental or may reflect the effects of the high-fiber diet of this region (see the image below).

The arterial supply of the colon is depicted in the image below. The resection of the colon is based on the arterial supply of its various anatomical divisions.

The ascending colon and cecum are supplied by the superior mesenteric artery via the ileocolic and right colic arteries. Adjacent to the colonic wall, these arteries form arcades that give off the vasa recta. The vasa recta divide into short and long branches that supply the medial and lateral aspects of the colon, respectively.

The middle colic artery forms an arcade with the left colic artery, which is a branch of the inferior mesenteric artery. The arcade is termed the marginal artery of Drummond. It lies in the mesenteric border adjacent to the colonic wall. The marginal artery gives off vasa recta to the transverse colon, the splenic flexure, and the descending colon. The sigmoid colon is supplied by branches of the left colic artery, as well as 2-4 sigmoidal arteries, which are branches of the inferior mesenteric artery, as shown below.

In 3-5% of the population, the right and the ileocolic arteries do not anastomose, creating an area of poor blood supply. Similarly, the point of Griffith is an area of poor blood supply in the region of the splenic flexure. The critical point of Sudeck was previously considered to be a similar watershed area of poor blood supply at the junction of the rectum with the sigmoid colon. Because of the extensive and intramural submucosal plexus of arteries formed by the branches of the superior, middle, and inferior rectal arteries, the rectum and distal sigmoid colon are well vascularized. In contrast, the vasa recta (the end arteries in the colon wall) are not well vascularized. For this reason, the clinical implications of the critical point of Sudeck are not as important.

The surgeon must always be aware of the location of the ureters in the retroperitoneum to avoid injuring them. The ureter is easily identified at the pelvic brim where it crosses over the external iliac artery. The ureter is visible as a white structure, which, on gentle compression, demonstrates characteristic propulsive movement.