Rationale: Adhesive small bowel obstruction (aSBO) is a frequent surgical emergency, associated with 3-8% hospital mortality and a high risk of recurrence (20% at two years of follow-up). ASBO can be treated conservatively or by emergency surgery. In the absence of bowel ischemia or strangulation, conservative treatment is often preferred, to avoid the excess morbidity and mortality from emergency surgery. Recent epidemiological studies, however, demonstrate a considerable higher recurrence risk of aSBO after conservative treatment that is associated with hospital readmissions and lower survival. Elective adhesiolysis following successful conservative treatment might reduce these long-term risks whilst avoiding the high complication rate of emergency surgery.

Objective: The investigators aim to assess the efficacy of elective adhesiolysis following conservative treatment for aSBO as compared to the current state of the art (wait-and-see policy) to prevent long-term recurrence of aSBO. Further the investigators will evaluate quality of life, healthcare and societal costs.

Study design: Multicenter open-label randomized controlled trial, including 380 patients.

Study population: Adult patients who recovered from aSBO by conservative treatment. Patients that are inoperable for medical, anaesthesiological or surgical reasons are excluded. Intervention (if applicable): The intervention of investigation is elective adhesiolysis. Adhesiolysis is an abdominal procedure in which all adhesions are cut, and adhesion prevention applied to reduce the risk of adhesion reformation. The intervention is compared to wait-and-see policy (the current standard treatment)

Main study parameters/endpoints: Primary outcome is recurrence, defined as readmission for obstructive systems with aetiology of adhesions confirmed by CT. The investigators hypothesize a 50% reduction in recurrence in the intervention arm. Secondary outcomes are morbidity from surgery, health-related quality of life (EQ5D), healthcare costs and societal costs (iMCQ and iPCQ)

Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

Patients in the intervention group are exposed to abdominal surgery, which is associated with a moderate risk of minor complications such as wound infection and haemorrhage, and a small risk of severe complications such as iatrogenic bowel injury. According to our hypothesis, a potential benefit is the reduction in the risk of recurrences. Recurrence of aSBO is associated with a risk of readmissions, reinterventions, and also increased long-term mortality.

Inclusion Criteria:

• Adult patients aged 18 years and older who have recently recovered from aSBO by small bowel obstruction managed by conservative treatment.
• Patients who have previously been operated (high a prior risk of adhesions) are required to have no signs of other causes of bowel obstruction on imaging studies (CT-scan).
• Patients with no previous operation in history (low a prior risk of adhesions) are required to have typical signs for aSBO on imaging studies (abrupt change of bowel calibre, closed loop, or signs of torsion on vessels in the mesentery on CT-scan).

Exclusion Criteria:

• Patient who are unfit for reoperation for surgical, anesthesiological or medical reasons as determined by multidisciplinary team assessment or pre-operative screening
• Patients with active malignancy, reducing life expectancy
• Pregnancy

At the end of the experiment and analyses, all data will be stored for 25 years in accordance with GCP regulations.

Access to individual data will be made available upon reasonable request for academic purposes