Who Should Undergo Drain Studies After Percutaneous Drainage in Complicated Diverticulitis?

Introduction: This study evaluated the role of interval drain studies following percutaneous abscess drainage in complicated diverticulitis. We sought to identify patients who would benefit from these studies by assessing predictive factors for a positive drain study (PDS). Methods: A single institution cohort study was performed on patients undergoing interval drain study following percutaneous abscess drainage for complicated diverticulitis. PDS was defined as persistence of abscess, increased size of abscess, or fistula formation. Demographics, admission data, drain study-specific findings, and readmission rates were assessed. Results: A total of 133 patients underwent drain studies. A total of 28 (21.1%) patients had a PDS and 105 (78.9%) had negative drain studies (NDS). PDS patients were more likely to have prior episodes of diverticulitis (50.0% vs. 33.3%, p = 0.045). Mean percent decrease in pre-to post-drain WBC was smaller in PDS patients (−8.7 vs. −17.9%, p < 0.001). A total of 78.6% of PDS patients had a persistent abscess and 14.3% had an increase in size of their abscess. Re-admission rate was higher in PDS patients (39.3% vs. 19.0%, p = 0.025). Prior history of diverticulitis, elevated BMI, and elevated pre- and post-drain WBC were predictors of PDS. Only prior history of diverticulitis (HR: 3.21, 95% CI: 1.14–9.03) was an independent predictor of PDS on multivariate analysis. Conclusion: Patients with prior episodes of diverticulitis were more likely to have PDS following percutaneous abscess drainage in complicated diverticulitis, with elevated BMI and percent decrease in pre-drain leukocytosis also being associated with PDS. These patients should receive stronger consideration for interval drain study.