Right- and left-sided diverticulitis have similar clinical presentations. However, there is limited and conflicting data on the surgical outcomes following resection for right-sided compared to left-sided diverticulitis. The aim of this study was to compare these outcomes.
All cases of right-sided colectomy (RC) and left-sided colectomy (LC) for diverticulitis were identified from the ACS National Surgical Quality Improvement Program database from 2005-2015.  Demographics, comorbidities, and postoperative outcomes were compared. Predictors of the pre-defined outcomes were analyzed by multivariate regression.
Of 50,588 patients identified, 710 underwent RC for diverticulitis and 49,878 underwent a LC. RC was associated with younger mean age (55.98 (±14.68) vs. 58.50 (±13.00), p<0.01) and Asian origin (3.66% vs. 0.84%, p<0.01). RC was more likely to be performed emergently (23.66% vs. 15.80%, p<0.01) and less likely to have a stoma (3.38% vs. 24.91%, p<0.01).  Furthermore, RC was associated with higher rates of anastomotic leak (6.36% vs. 3.16%, p<0.01), reoperation (7.18% vs. 4.80%, p <0.01), and increased length of stay (median [IQR] 6 [4,10] vs. 5 [4, 8] days, p<0.01), without any differences in overall 30-day major morbidity (19.44 vs. 16.77, p=0.06) or mortality (1.83% vs. 1.30%, p=0.24). On multivariate analysis, RC was a predictor of anastomotic leak (OR 2.04, 95%CI 1.13-3.68), major morbidity (OR 1.31, 95%CI 1.06-1.63) and increased length of stay (0.19 days, 95%CI 0.15-0.24). Emergency surgery was also a predictor for major morbidity (OR 1.42, 95%CI 1.53-2.66) for both RC and LC, while increased age, ASA of 4 or 5, congestive heart failure, immunosuppression, contaminated/dirty wounds, and pre-operative sepsis were predictors of mortality.  Type of colectomy (right vs. left-sided) was not a predictor of mortality. 
RC was more likely to be performed emergently compared to LC for diverticulitis, and was associated with significantly greater rates of major morbidity, anastomotic leak and reoperation.

Right-sided Colectomies for Diverticulitis Have Worse Outcomes Compared to Left-sided Colectomies for Diverticulitis: An ACS NSQIP analysis of Predictors and Outcomes