[ second attack would have prevented 29 recurrent attacks by performing 57 operations, of which 28 would not have been necessary. The authors subsequently updated their series and stated that there was no data to support resec­tion after the second attack of diverticulitis [ 15 ]. An addi- tional study of 2,551 patients who were initially treated successfully medically for diverticulitis (with a mean fol­low-up of 9 years) resulted in only 13 % of patients with recurrent attacks and only 7 % of patients who required colectomy [ sigmoid diverticulitis was found to be safe in the short and long term in a prospectively followed cohort of 232 patients from 1990 to 2004 [ 17 ]. Thus, several studies have suggested that the majority of patients who recover from an episode of diverticulitis have no further attacks. Evaluation of inpatients may be associated with a higher risk of diverticulitis, presumably since such patients, compared to outpatients, would be expected to have more severe diverticulitis. We have found a 36 % recurrence rate in 672 patients, the majority of whom were treated as inpatients [ 18 ]. The risk of recurrent diverticulitis appears to vary markedly, and patients with more severe disease most likely have a higher recurrence rate. Further inves­tigations should focus on groups of patients at the high­est risk for development of recurrent diverticulitis. The most recent practice parameters of the American Society of Colon and Rectal Surgeons suggest that the number of attacks of uncomplicated diverticulitis is “not necessar­ily the overriding factor in defi ning the appropriateness of surgery” [ 11 ].

We have noted that patients with a longer segment of dis­ease (>5 cm) are more likely to have recurrent attacks of diverticulitis and have used this as one parameter in advising patients to have sigmoid resection after multiple attacks of diverticulitis [ 18 ]. We have also developed a scoring system for those patients who are less likely to resolve on conserva­tive measures and require resection [ 28 ]. The scoring system is a point system that determines the risk of surgery within 90 days. The points are given for abscess >4 cm (2 points), pericolic free air (2 points), segment greater than 5 cm (2 points), pericolic abscess (5 points), and distant free air (7 points). Patients with 0–4 points have a less than 25 % risk of surgery in 90 days, patients with 5–9 points have a 25–50 % risk of surgery, and patients with >9 points have over a 50 % risk of requiring surgery with 90 days of presentation.