General Considerations

  • Twisting of loop of intestine around its mesenteric attachment site may occur at various sites in the GI tract
    • Most commonly: sigmoid & cecum
    • Rarely: stomach, small intestine, transverse colon
    • Results in partial or complete obstruction
    • May also compromise bowel circulation resulting in ischemia
  • Sigmoid volvulus most common form of GI tract volvulus
    • Accounts for up to 8% of all intestinal obstructions
  • Most common in elderly persons (often neurologically impaired)
  • Patients almost always have a history of chronic constipation

Pathophysiology

  • Redundant sigmoid colon that has a narrow mesenteric attachment to posterior abdominal wall allows close approximation of 2 limbs of sigmoid colon à twisting of sigmoid colon around mesenteric axis
  • Other predisposing factors
    • Chronic constipation
    • High-roughage diet (may cause a long, redundant sigmoid colon)
    • Roundworm infestation
    • Megacolon (often due to Chagas dz)
  • 20-25% mortality rate
  • Peak age > 50 yrs.
    • Second largest group à children
  • Torsion usually counterclockwise ranging from 180 – 540 degrees
  • Luminal obstruction generally @ 180 degrees
  • Venous occlusion generally @ 360 degrees à gangrene & perforation
  • Signs and symptoms
    • May present as abdominal emergency
      • Acute distension
      • Colicky pain (often LLQ)
      • Failure to pass flatus or stool (constipation is prevailing feature)
      • Vomiting is late sign
    • Distention may compromise respiratory & cardiac function
    • May also present with surprisingly few signs and symptoms in bedridden and debilitated
  • Physical examination
    • Tympanitic abdomen
    • Abdominal distention
    • +/- palpable mass

Diagnosis

  • Abdominal plain films usually diagnostic
    • Inverted U-shaped appearance of distended sigmoid loop
      • Largest  and most dilated loops of bowel are seen with volvulus
    • Loss of haustra
    • Coffee-bean sign à midline crease corresponding to mesenteric root in a greatly distended sigmoid
    • Bird’s-beak or bird-of-prey sign à seen on barium enema as it encounters the volvulated loop
  • CT scan useful in assessing mural wall ischemia

Differential Diagnosis

  • Large bowel obstruction due to other causes à sigmoid colon CA
  • Giant sigmoid diverticulum
  • Pseudo-obstruction
  • Colonic ischemia
  • Perforation
  • Sepsis

Treatment

  • Laparoscopic de-rotation or laparotomy +/- bowel resection
  • De-rotation & decompression by barium enema or with rectal tube, colonoscope, or sigmoidoscope if no signs of bowel ischemia or perforation
  • Cecopexy à suture fixation of bowel to parietal peritoneum may prevent recurrence
  • Recurrence rate after decompression alone à 50%

Sigmoid volvulus


Sigmoid Volvulus. Dilated loop of sigmoid colon has a "coffee-bean" shape and
the wall between the two volvulated loops of sigmoid (black arrow) "points" towards the right upper quadrant.
There is a considerable amount of stool in the colon from chronic constipation.