Int J Colorectal Dis (2012) 27:207–214 (laparoscopic) sigmoid resection is probably the final resolu- tion. When a general peritonitis is suspected on physical examination, confirmed by CT scan, surgical intervention is warranted. According to current literature, a safe strategy might be to primarily perform a diagnostic laparoscopy. In the case of a purulent peritonitis, either (laparoscopic) sigmoid resection with primary anastomosis (with or without defunc- tioning stoma) or even laparoscopic lavage may be considered in selected cases. When fecal contamination is discovered, Hartmann’s procedure is still considered the safest option, but in select cases, a primary anastomosis (with or without defunctioning stoma) might be a safe alternative. In most classifications, post-inflammatory changes like stenosis or fistulas are not included. Patients may have serious complaints, but interventions can usually be postponed to an elective setting. Stage B includes non-acute complications of diverticular disease, such as symptomatic stenosis, fistulas to hollow organ, recurrent (self-limiting) diverticular bleeding, and incapacitating complaints. This last group of patients covers mainly those young patients who are incapacitated by recurrent attacks and hospital admissions, which prevent them from having normal working careers and social life. In addition, high-risk patients, such as those immune compro- mised, using of NSAIDs and other immune suppressants or experiencing chronic renal failure, might be good candidates for early elective sigmoid resection. The planning of an elective operation makes it possible to do a proper preoper- ative work-up to prevent unwelcome surprises during surgery. In cases of stenosis or recurrent rectal blood loss, it is advisable to perform a colonoscopy to rule out cancer. CT scan is of superior diagnostic value in case of stenosis or fistula. During preoperative planning of complex fistula, MRI might have some benefit over CT scan. Stage B disease forms indications for elective sigmoid resections, preferably laparoscopically. Stage A contains symptomatic uncomplicated disease. Patients with subclinical complaints or recurrent hospital admission should not be considered differently because both groups will fully recover with conservative measures. Acute episodes of stage A diverticulitis can mostly be resolved with antibiotics and a low residue diet. Recurrent episodes usually follow a benign course and risks of complications are low. At presentation, a CT scan or US (provided an experienced radiologist is available) has to be performed to rule out complicated disease. Moreover, these baseline findings are crucial if the patient deteriorates during conservative treatment. Small amounts of mucus or blood loss are generic signs of inflammation, whereby colonoscopy has to rule out other inflammatory bowel diseases or colon cancer. After a first attack, preventive measures have to be taken into account, such as high-fiber diet, weight loss, and treatment of comorbid conditions. In the near 213 future, the prescription of Mesalazine might be added to this preventive strategy. In conclusion, this manuscript provides an overview of current classification systems for diverticular disease. The proposed three-stage model provides a renewed and comprehensive classification system for diverticular disease, incorporating up-to-date imaging and (future) treatment modalities. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. 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