Association of hospital volume with conversion to open from minimally invasive colectomy in patients with diverticulitis: A national analysis

BACKGROUND: Despite the known advantages of minimally invasive surgery (MIS) for diverticular disease, the impact of conversions to open (CtO) colectomy remains understudied. The present study used a nationally representative database to characterize risk factors and outcomes associated with CtO in patients with diverticular disease. METHODS: All elective adult hospitalizations entailing colectomy for diverticulitis were identified in the 2017–2019 Nationwide Readmissions Database. Annual institutional caseloads of MIS and open colectomy were independently tabulated. Restricted cubic splines were utilized to non-linearly estimate the risk-adjusted association between hospital volumes and CtO. Additional regression models were developed to evaluate the association of CtO with outcomes of interest. RESULTS: Of an estimated 110,281 patients with diverticulitis who met study criteria, 39.3% underwent planned open colectomy, 53.3% completed MIS, and 7.4% had a CtO. Following adjustment, an inverse relationship between hospital MIS volume and risk of CtO was observed. In contrast, increasing hospital open volume was positively associated with greater risk of CtO. On multivariable analysis, CtO was associated with lower odds of mortality (AOR 0.3, p = 0.001) when compared to open approach, and similar risk of mortality when compared to completed MIS (AOR 0.7, p = 0.436). CONCLUSION: In the present study, institutional MIS volume exhibited inverse correlation with adjusted rates of CtO, independent of open colectomy volume. CtO was associated with decreased rates of mortality compared to planned open approach but equivalence risk relative to completed MIS. Our findings highlight the importance of MIS experience and suggest that MIS may be safely pursued as the initial surgical approach among diverticulitis patients.