Adhesive small bowel obstruction - an update

Abstract

Small bowel obstruction (SBO) accounts for 12-16% of emergency surgical admissions and 20% of emergency surgical procedures. Even with the advent of laparoscopic surgery, intra-abdominal adhesions remain a significant cause of SBO, accounting for 65% of cases. History and physical examination are essential to identify signs of bowel ischemia as this indicates a need for urgent surgical exploration. Another critical aspect of evaluation includes establishing the underlying cause for obstruction and distinguishing between adhesive and non-adhesive etiologies as adhesive SBO (ASBO) can be managed non-operatively in 70-90% of patients. A patient with a history of abdominopelvic surgery along with one or more cardinal features of obstruction should be suspected to have ASBO until proven otherwise. Triad of severe pain, pain out of proportion to the clinical findings, and presence of an abdominal scar suggest possible closed-loop obstruction. Computed tomography has higher sensitivity and specificity compared to plain films and is recommended by the Bologna guidelines. Correcting fluid and electrolyte imbalance is an initial crucial step to mitigate severe hypovolemia. Patients should proceed with surgery if symptoms of bowel compromise are present, or if symptoms do not resolve or have worsened. Surgery is indicated in patients with ischemia, strangulation, perforation, peritonitis, or failure of non-operative treatment. With advances in minimal access technology and increasing experience, laparoscopic adhesiolysis is recommended. Mechanical adhesion barriers are an effective measure to prevent adhesion formation.

Keywords: Gastrointestinal tract; general surgery; intestinal obstruction; small intestine; tissue adhesion.

Fig. 1

A patient with no relevant medical history showed symptoms of small bowel obstruction. The computed tomography scan shows dilated distal jejunal loop with a transition point suggestive of small bowel obstruction. At laparotomy, a congenital adhesion band from the root of the mesentery to the bowel loop was detected and lysed. Yellow arrow indicates the transition point.

Fig. 2

A patient with a history of tubal ligation carried out more than a decade ago showed symptoms of small bowel obstruction. The computed tomography scan shows dilated distal jejunal loop with abrupt transition, suggestive of small bowel obstruction. Yellow arrow indicates the transition point.

Fig. 3

A patient with a history of surgery for intussusception as an infant and showing symptoms of small bowel obstruction. The computed tomography scan shows dilated distal jejunal loop with two transition points close to each other, suggestive of closed‐loop small bowel obstruction. Top left inset: intraoperative photograph of bowel ischemia caused by small bowel obstruction secondary to acquired adhesions. Yellow and blue arrows point to the transition points of the closed‐loop obstruction.

Fig. 4

Pathogenesis of acquired adhesions in the small bowel. MMP, matrix metalloproteinase; PAI, plasminogen activator inhibitor; TGF‐β transforming growth factor‐β; TIMP, tissue inhibitor of metalloproteinase; tPA, tissue plasminogen activator.

Fig. 5

Pathophysiology of small bowel obstruction (SBO). ASBO, adhesive SBO; BUN, blood urea nitrogen; CRP, C‐reactive protein; FBC, full blood count; I‐FABP, intestinal fatty acid‐binding protein; NBM, nil by mouth; NGT, nasogastric tube.

Fig. 6

Approach to adhesive small bowel obstruction (ASBO) evaluation and management.

Fig. 7

A patient with a history of laparoscopic appendectomy 2 years ago and showing symptoms of small bowel obstruction. A barium meal and follow‐through after 100 mL undiluted Omnipaque dye insertion through a nasogastric tube showing dilated small bowel loops (up to 4.3 cm) and prolonged transit (>7.5 h) without the flow of contrast into the large bowel, suggestive of high‐grade small bowel obstruction.