Bowel adhesions are a major cause of small bowel obstruction, accounting for around 60% of cases. Whilst a rare few are congenital in cause, the majority occur secondary to previous surgery.
Fibrous bands can occur in up to 93% of patients after undergoing abdominal surgery, with the actual incidence of small bowel obstruction reported to be around 9%. Fibrous adhesions are also associated with female infertility and chronic pelvic pain.
A recent meta-analysis showed the incidence of small bowel obstruction was greatest in lower GI surgery and paediatric surgery, and the lowest in abdominal wall surgery, upper GI surgery, and urological surgery.
Patients with bowel adhesions will classically present with the clinical features of bowel obstruction – abdominal pain, vomiting, abdominal distention, and absolute constipation.
It is important to palpate for signs of localised tenderness or peritonism, to rule out any indication of bowel ischaemia.
Much of the work-up required for suspected bowel adhesions is directed to that of bowel obstruction.
Routine bloods are required (FBC, U&E, LFTs, Clotting), as well as a Group and Save or Crossmatch (depending on the likelihood of the patient requiring surgical intervention). Monitor electrolytes for signs of dehydration.
An arterial blood gas (ABG) is required if there are any signs of ischaemia or perforation. Whilst not specific, serum lactate is highly sensitive for bowel ischemia thus is a robust sign to proceed for urgent surgery.
As with any case of bowel obstruction, suspected bowel adhesions warrants a plain film abdominal X-ray (AXR) to assess for features of bowel obstruction. If perforation is suspected, an erect chest X-ray (eCXR) may also be required.
However, if the cause is unknown or further details are required, an abdominal CT scan may be requested, providing details on location of the adhesions and identifying any complications (e.g. ischaemia or perforation)
Conservative management should be attempted initially in patients presenting with uncomplicated bowel obstruction.
The mainstay of conservative management is tube decompression. This involves passing a tube into the stomach (nasogastric tube) or, less commonly, into the small intestine (long tube), allowing any build up of pressure to be released*.
*No difference has been reported between NG tube and long tube decompression in the conservative management of bowel adhesions.
Additionally, the patient should be kept nil-by-mouth, started on IV fluids, and provided with adequate analgesia. Any electrolyte abnormalities or fluid deficits should be corrected accordingly.
Surgical intervention is warranted in any patient with clinical features of ischaemia or perforation, worrying features on CT scan (evidence of free intraperitoneal fluid, mesenteric oedema, or bowel ischaemia), or failed conservative treatment.
Whilst open management is still performed in some cases, laparoscopic management for bowel adhesions is becoming the mainstay – allowing for faster return of intestinal function, shorter hospital stays, fewer wound complications, and decreased postoperative adhesion formation.
Laparoscopic adhesiolysis is technically challenging, due to the distension of the bowel and the increased risk of iatrogenic injuries if the small bowel is not handled appropriately. Hence, there should be a low threshold for conversion to open approach in extensive disease.
Adhesiolysis should be limited to only the adhesions causing the mechanical obstruction or strangulation, in an aim to reduce risk of recurrent adhesional disease.
Note: In patients that require surgical management, early intervention is preferable – as a recent study found that delay to operation for bowel adhesions had increased rates of post-operative complications, bowel resection, prolonged length of stay, and mortality.
There are no devices currently able to totally prevent adhesion formation after abdominal surgery.
Correct surgical technical and reducing traumatic intraperitoneal organ handling remain the mainstay of reducing bowel adhesion formation.