WTP4.9 Use of the American Association for Surgery and Trauma (AAST) Scale as a Predictive Tool in the Laparoscopic Approach to Adhesive Small Bowel Obstruction in a Tertiary Hospital

Aims

The laparoscopic approach (LA) in treating adhesive small bowel obstruction (ASBO) has been shown to be a beneficial technique. Despite being a minimally invasive procedure, it is still not a widespread technique.

Tools to identify which patients with ASBO may benefit from LA are needed. The AAST scale classifies ASBO into five grades of obstruction, differentiated by radiological, intraoperative, and pathological findings.

The correlation between AAST-radiological and AAST-intraoperative is evaluated, as well as the association between the AAST scale and the rate of conversion to open surgery.

Methods

Observational, descriptive, retrospective, single-center, retrospective study from January 2011 to April 2022 of patients undergoing emergency laparoscopic surgery for suspected ASBO.

Results

43 patients were analyzed. By CT scan 13.5% of patients had AAST-I, 43.2% AAST-II, and 43.2% AAST-III. Intraoperatively 11.6% of patients had AAST-I, 46.5% AAST-II, 25.5% AAST-III, 13.9% AAST-IV, and 2.3% AAST-V. The overall conversion rate was 27.9%. Using the univariate logistic regression model, an association was found between conversion rate and intraoperative AAST, as patients with an AAST≤II were less likely to convert to open surgery (OR 0.03, 95%, CI 0.00-0.26, p=0.03). This association was not observed between conversion rate and AAST-radiological. The degree of agreement between radiological-AAST vs intraoperative-AAST was moderate (Kappa coefficient 0.532).

Conclusions

Although radiological AAST is a guiding tool in selecting patients in whom the entire LA can be performed, it is the intraoperative findings that increase conversion, which encourages a laparoscopic approach in these cases.