Volvulus

New dedicated page — previously covered only in passing (as a large bowel obstruction etiology) on Large Bowel Obstruction. Content below is from a single textbook reference chapter (ASCRS Ch39 - Large Bowel Obstruction), not primary literature.

Definition and general epidemiology

Axial torsion of a mobile colonic segment along its mesentery, producing a closed-loop obstruction (see Large Bowel Obstruction's Closed-loop obstruction section for the shared physiology). Over time the volvulized segment, and the colon proximal to it, can distend to the point of ischemia and perforation unless reduced — spontaneously or via intervention. Any mobile colonic segment can volvulize, but the sigmoid colon (~60% of cases) and cecum (~40% of cases) account for the overwhelming majority; volvulus of the transverse colon, splenic flexure, or other segments is rare. For unclear reasons, sigmoid volvulus most commonly twists counterclockwise, while cecal volvulus tends to twist clockwise.

Risk factors: anatomy amenable to volvulization (e.g., a redundant colon with a relatively narrow mesentery), constipation or colonic dysmotility, prior abdominal surgery, and prior volvulus. Sigmoid volvulus is more common in patients who are male, >70 years old, African American, diabetic, or institutionalized/have neuropsychiatric comorbidities; cecal volvulus patients tend to be younger and more often female.

Geography: colonic volvulus is relatively uncommon in the United States (~10–15% of large bowel obstructions, ~3–5% of all bowel obstructions). In parts of Africa, the Middle East, India, Brazil, and South America (the so-called "volvulus belt"), volvulus is far more endemic and may account for up to 40% of bowel obstructions — thought to be multifactorial (diet, altitude, cultural factors, certain infections).

Presentation and diagnosis

Abdominal distension, decreased bowel function/obstipation, nausea, and abdominal pain. A secondary small bowel obstruction can develop via decompression of the colon through an incompetent ileocecal valve, which can also produce vomiting. Progression to colonic ischemia and perforation presents as an abdominal catastrophe with sepsis. Imaging (abdominal radiographs and/or CT) typically confirms the diagnosis when the differential is broad; in emergency cases or where imaging is equivocal, volvulus is confirmed at exploration.

Plain radiograph/CT topogram: classic "coffee bean" or "bent inner tube" sign — the appearance of a massively dilated volvulized colonic segment. The "northern exposure sign" describes the apex of a volvulized sigmoid loop projecting cranial to the transverse colon.
Water-soluble contrast enema: "bird's beak" sign — tapering of the colon lumen at the twisted distal limb.
CT: may show a "swirl" or "whirl" sign depicting the torsed mesenteric vessels. CT has effectively supplanted plain radiographs/contrast enema as the preferred diagnostic modality — nearly 100% sensitivity and >90% specificity for volvulus — and can additionally identify signs of complicated volvulus (ischemia/perforation): intravenous-contrast enhancement defects from arterial occlusion, colon wall thickening from venous occlusion, pneumatosis intestinalis, free peritoneal fluid, mesenteric/portal venous gas, and pneumoperitoneum. Cross-sectional imaging can nonetheless be challenging to interpret depending on the degree of proximal bowel dilation, which may explain why some patients aren't diagnosed until exploration.

Sigmoid volvulus

Nonoperative detorsion

Patients with radiographic evidence of sigmoid volvulus, without peritonitis, perforation, clinical instability, or sepsis, are typically managed with an attempt at endoscopic detorsion. Patients should be counseled that detorsion attempts risk failure as well as perforation.

Rigid proctoscopy: performed at the bedside (left decubitus position, usually without sedation) after consent. The volvulized mucosa has a characteristic twisting/"pinwheel" appearance. With continued insufflation and gentle manipulation, the colon can usually be untwisted and the proximal sigmoid intubated; venting the trapped gas/liquid produces a dramatic decompression. Once the previously volvulized segment is intubated, the mucosa should be evaluated for ischemia (which should prompt a plan for colectomy); absent concerning findings, a transrectal decompression tube is placed — not primarily to vent (it typically clogs with stool) but to stent the segment against immediate recurrence, allowing time for bowel prep ahead of semi-elective colectomy. A semi-rigid chest tube passed through the proctoscope and sutured to the perianal skin serves this purpose. Post-detorsion abdominal radiographs can confirm tube position/decompression and absence of free air.
Flexible sigmoidoscopy: an alternative when the volvulus level is more proximal than a proctoscope's reach, using water immersion or gas insufflation as needed; fluoroscopic guidance can help in select cases. Prior to proceeding with colectomy in the non-emergent setting, this may be combined with CT colonography.
Success/risk: nonoperative detorsion is successful in 60–95% of cases with a low morbidity rate, but carries an estimated 3% mortality — thought to reflect the typical volvulus patient population's comorbidity burden rather than the procedure itself.
Recurrence: after successful nonoperative decompression alone (no interval resection), the risk of recurrence after a first admission is estimated at 45–70% or higher depending on follow-up length, with most recurrences within the first few months. This drives the standard recommendation for interval sigmoidectomy (see below) rather than decompression alone as definitive management.

Surgery for sigmoid volvulus

Patients with evidence of perforation or concern for ischemia proceed directly to exploratory laparotomy with broad-spectrum antibiotics and IV fluid resuscitation; colon ischemia and peritonitis are the main mortality risk factors, with emergency-presentation volvulus mortality as high as 33% or higher. A laparoscopic approach may be used depending on patient circumstances and surgeon expertise, though the redundant, dilated sigmoid colon (even after successful endoscopic detorsion/decompression) is often difficult to negotiate laparoscopically and tends to prolapse out readily through a relatively short midline laparotomy. Unlike some other left-colon resections, the splenic flexure does not typically need to be released for this operation.

Sigmoid colectomy (resection of the redundant sigmoid to minimize recurrent-volvulus risk) is the most common operation. Extended resection (subtotal colectomy) is indicated for: cecal perforation complicating sigmoid volvulus (addresses both sites of pathology); colonic ischemia proximal to the volvulized loop (often patchy/diffuse, requiring subtotal resection); and concomitant megacolon (subtotal colectomy can prevent recurrent volvulus at an otherwise-retained segment). For a gangrenous, volvulized segment, the general recommendation is to resect the loop without reducing the twist first, to avoid a load of potassium, bacteria, and endotoxin entering the circulation — though an oncologic nodal catch is not required, so it's usually technically helpful to ligate the main mesenteric pedicle close to the colon wall rather than dissect repeatedly through the folded, thickened mesentery. Care should be taken to identify the left ureter, and a mid-mesenteric dissection plane is preferable to avoid the retroperitoneum.

Restoring continuity: in emergency operations, the decision to anastomose is based on individualized risk assessment and clinical status; patients should be sited/marked for a stoma location preoperatively regardless. In semi-elective/elective operations for previously-detorsed volvulus, an anastomosis is commonly created — often with a wide diameter mismatch that can make seating a circular-stapler anvil for an end-to-end anastomosis suboptimal, in which case closing the colon with a linear stapler and performing a side-to-end Baker-type anastomosis can help (see Anastomotic Construction for this wiki's general side-to-end/Baker anastomosis technique detail).

Non-resectional alternatives to sigmoidectomy — simple operative detorsion alone, meso-sigmoidoplasty, and sigmoidopexy — spare the morbidity risk of stoma creation or anastomosis but carry much higher rates of recurrent volvulus.

Percutaneous endoscopic colostomy/sigmoidopexy (PEC): fixes the sigmoid colon to the anterior abdominal wall to restrict colonic mobility and reduce recurrence risk, usually under conscious sedation — a potential option for patients with prohibitive operative risk or who decline abdominal surgery. Can be combined with laparoscopy to ensure proper alignment before fixation and reduce the risk of injury to nearby structures. Considered minimally invasive, though questions remain regarding optimal number of fixation points (one vs. two) and timing of device removal (early removal has been associated with recurrent volvulus); reported complications range from infection/bleeding at the PEC site to peritonitis from PEC migration/dislodgement. Because patients selected for PEC typically have significant comorbidities precluding abdominal surgery, even minor endoscopic-related complications can have severe consequences — reports with follow-up data show a notably high mortality rate after PEC from unrelated causes in this particularly vulnerable population.

Cecal volvulus

In contrast to sigmoid volvulus, nonoperative detorsion success is low, and the general consensus is not to delay operation (risking ischemia, necrosis, and perforation). Cecal volvulus is considered a surgical emergency even without overt sepsis; patients typically receive broad-spectrum antibiotics and IV fluid resuscitation as the OR is mobilized. As with sigmoid volvulus, open vs. laparoscopic approach depends on clinical circumstances and available expertise, but the typical specimen size usually requires a meaningful extraction incision regardless, and the dilated/displaced/elongated colon can be difficult to negotiate laparoscopically.

Ileocolectomy with anastomosis is the most common operation, both to treat and to prevent recurrent cecal volvulus. Where an ileocolic anastomosis is considered too high-risk, an end ileostomy with or without a mucous fistula is performed. In select unstable patients, the bowel may be resected, left in discontinuity, and the patient brought back for a "second look" with possible anastomosis at that time. Non-resectional alternatives (simple detorsion alone, cecopexy, cecostomy) carry a risk of recurrent volvulus, similar in principle to the sigmoid analogs above. Given the risks and benefits of the various approaches, resection-based therapy is most commonly favored, though individualization has a role.

Cecal bascule: a rare entity distinct from volvulus in that there is no axial torsion across the mesenteric axis — instead, the caput of the cecum is displaced anteriorly and folds over the ascending colon, closing off the cecum. In the setting of a competent ileocecal valve, this configuration can cause a closed-loop obstruction. May be demonstrated on cross-sectional imaging but is commonly diagnosed at exploration. Evaluation and treatment mirror those for cecal volvulus.

Mobile cecum syndrome: a poorly defined entity, distinct from volvulus, postulated to result from an embryologic abnormality in which the lateral peritoneal attachments of the ascending colon are absent, permitting a degree of cecal mobility hypothesized to cause related symptoms. There's a paucity of high-quality or population-based evidence on this condition; in practice, patients present with episodic bloating, distension, and pain that resolve after an explosive, decompressive bowel movement, with imaging showing colonic dilation but no volvulus. The proposed treatment is laparoscopic cecopexy, though criteria for intervention and post-cecopexy outcomes data are not well established. The concept of a "pre-volvulus" condition is not well described, and operative intervention under these circumstances — despite patient/referring-physician insistence — is not generally supported by the evidence.

Ileosigmoid knotting: rare in the United States, more common in volvulus-belt regions. Multiple knotting configurations have been described, all involving the ileum and sigmoid colon wrapping around each other, frequently progressing to ischemia in one or both segments. The "double-loop" obstruction pattern carries a poor prognosis; patients commonly present with an abdominal catastrophe, and mortality can be as high as 73%. Diagnosis is made by cross-sectional imaging but is often made at exploration; a combination of imaging findings suggesting sigmoid volvulus plus a secondary small bowel obstruction, with inability to reduce the sigmoid volvulus endoscopically, may raise suspicion. Operative treatment depends on the specific anatomic variant encountered and often involves resection of both involved segments, with or without restoration of bowel continuity depending on anatomy and circumstances.

Large Bowel Obstruction — the broader LBO condition page; this page's shared closed-loop obstruction physiology, and etiology-general diagnosis/imaging approach, is covered there in less volvulus-specific detail.
Anastomotic Construction — general side-to-end/Baker anastomosis technique referenced above for size-mismatched sigmoid-volvulus anastomoses.
Colonic Pseudo-Obstruction (Ogilvie Syndrome) — the differential-diagnosis counterpart for colonic dilation without a mechanical (volvulus or otherwise) obstruction.

Open items / gaps

All content on this page is from a single textbook reference chapter — no primary literature (RCTs, the SCOTIA-adjacent trials referenced elsewhere, individual case series behind the cited recurrence/mortality figures) independently ingested yet.
PEC's optimal fixation-point count and device-removal timing are described as open questions in the source chapter itself — not resolved here.
No data yet on long-term outcomes/quality of life after subtotal colectomy for sigmoid volvulus with megacolon, or after non-resectional alternatives (mesosigmoidoplasty, sigmoidopexy) specifically — only their comparatively higher recurrence rates are quantified.

Colorectal LLM Wiki