Prophylactic Drainage after Appendectomy for Perforated Appendicitis in Adults: A Post Hoc Analysis of an EAST Multi-Center Study.

We sought to assess the efficacy of prophylactic abdominal drainage to prevent complications after appendectomy for perforated appendicitis. In this post hoc analysis of a prospective multi-center study of appendicitis in adults (≥ 18 years), we included patients with perforated appendicitis diagnosed intra-operatively. The 634 subjects were divided into groups on the basis of receipt of prophylactic drains. The demographics and outcomes analyzed were surgical site infection (SSI), intra-abdominal abscess (IAA), Clavien-Dindo complications, secondary interventions, and hospital length of stay (LOS). Multivariable logistic regression for the cumulative 30-day incidence of IAA was performed controlling for age, Charlson Comorbidity Index (CCI), antibiotic duration, presence of drains, and Operative American Association for the Surgery of Trauma (AAST) Grade. In comparing the Drain (n = 159) versus No-Drain (n = 475) groups, there was no difference in the frequency of male gender (61% versus 55%; p = 0.168), weight (87.9 ± 27.9 versus 83.8 ± 23.4 kg; p = 0.071), Alvarado score (7 [6-8] versus 7 [6-8]; p = 0.591), white blood cell (WBC) count (14.8 ± 4.8 versus 14.9 ± 4.5; p = 0.867), or CCI (1 [0-3] versus 1 [0-2]; p = 0.113). The Drain group was significantly older (51 ± 16 versus 48 ± 17 years; p = 0.017). Drain use increased as AAST EGS Appendicitis Operative Severity Grade increased: Grade 3 (62/311; 20%), Grade 4 (46/168; 27%), and Grade 5 (51/155; 33%); p = 0.007. For index hospitalization, the Drain group had a higher complication rate (43% versus 28%; p = 0.001) and longer LOS (4 [3-7] versus 3 [1-5] days; p < 0.001). We could not detect a difference between the groups in the incidence of SSI, IAA, or secondary interventions. There was no difference in 30-day emergency department visits, re-admissions, or secondary interventions. Multi-variable logistic regression showed that only AAST Grade (odds ratio 2.7; 95% confidence interval7 1.5-4.7; p = 0.001) was predictive of the cumulative 30-day incidence of IAA. Prophylactic drainage after appendectomy for perforated appendicitis in adults is not associated with fewer intra-abdominal abscesses but is associated with longer hospital LOS. Increasing AAST EGS Appendicitis Operative Grade is a strong predictor of intra-abdominal abscess.