COMMENT ON
MY Beg, L Bains, P Lai et al. Small bowel knots. Ann R Coll Surg Engl 2020; 102: 571–576. doi 10.1308/rcsann.2020.0122
Dear Sir,
I read with interest the review on small bowel knots by Beg et al, who presented a case with ileoileal knotting arising from ileoileal and ileocaecal intussusception. As the authors stated, intestinal knotting is one of the less common causes of intestinal obstruction. Although ileosigmoid knotting (ISK), the wrapping of the ileum or sigmoid colon around the other structure, causing a double loop intestinal obstruction, is the most common among intestinal knots, it is a very rare entity worldwide with only a few hundred cases reported.1 However, it is relatively common in eastern Anatolia, where I practise. My colleagues and I have dealt with 80 cases of ISK over a 54-year period from June 1966 to date, which is one of the largest single centre ISK series in the world.2 Here, I would like to discuss some details of intestinal knots relating to the patient described by Beg et al.
First, a hypermobile terminal ileum with a long mesentery is the main anatomical prerequisite for ileoileal knotting; in addition, a dilated sigmoid colon with an elongated mesentery is required for the development of ISK.3 Nevertheless, even when these anatomical prerequisites are present, ISK does not develop in all people at risk and a trigger action is required for the development of knot formation. In my opinion and experience, bowel hypermotility (as seen in acute diarrhoea) is the most important precipitating factor in the development of a knot. In our series, 17 patients (21.3%) had a 1–3-day history of diarrhoea prior to the main clinical features. Increased bowel peristalsis may stimulate a rotation, causing a knot. Consequently, according to the hypothesis of Beg et al, ileoileal intussusception may lead to sudden peristalsis of the ileum and turning of loops, causing knot formation in the case presented, which supports my idea.
Second, while abdominal x-ray radiography generally reveals dilated bowel loops as well as multiple intestinal air–fluid levels in the knot, computed tomography is highly diagnostic, showing the mesenteric whirlpool sign in addition to the enlarged loops,2,4 as demonstrated by Beg et al. In my experience, following the usage of computed tomography by the 2000s, the diagnostic accuracy of ISK clearly increased from 15–20% to 90%.
Finally, although endoscopy may demonstrate the mucosal viability of the distal loop, it cannot give information about the proximal loop. Moreover, the unravelling of the knot is often very difficult or impossible. For this reason, emergency laparotomy is required in the treatment of almost all cases of intestinal knotting.2,5 In those with gangrenous bowel, following the resection of the unviable segments, primary anastomosis is preferred in otherwise relatively fit individuals (as in the patient of Beg et al) while a stoma can be life saving in cases with poor general conditions.2,5
I congratulate the authors on their paper and look forward to their reply.
References
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