Defining the post-operative morbidity index for distal pancreatectomy

Background: Accurate assessment of complications is critical in analysing surgical outcomes. The post-operative morbidity index (PMI), derived from the Modified Accordion Severity Grading System and American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP), is a quantitative measure of post-operative morbidity. This study utilizes PMI to establish the complication burden for a distal pancreatectomy (DP). Methods: From 2005-2011, nine centres contributed ACS-NSQIP complication data for 655 DPs. Each complication was assigned an Accordion severity weight ranging from 0.11 for grade 1 to 1.00 for grade 6 (death). The PMI is the sum of complication severity weights divided by the total number of patients. Results: ACS-NSQIP complications occurred in 177 patients (27.0%). The non risk-adjusted PMI for DP is 0.087. Bleeding/Transfusion and Organ Space Infection were the most common complications. Frequency and burden differed across Accordion grades. While grade 4-6 complications represented only 15.4% of complication occurrences, they accounted for 30.4% of the burden. Subgroup analysis demonstrates that the PMI did not vary based on laparoscopic versus open approach or the performance of a splenectomy. Discussion: This study uses two validated systems to quantitatively establish the morbidity of a DP. The PMI allows estimation of both the frequency and severity of complications and thus provides a more comprehensive assessment of risk.