Objective：To investigate the timing of the surgical intervention  in the infection phase of severe acute pancreatitis (SAP).
Methods：The clinical data of 88 SAP patients admitted in Nankai hospital, who underwent surgical treatment in the infection phase, from January 2003 to January 2011 were retrospectively analyzed. According to the time span from the onset of SAP to receiving surgery, the patients were divided into group A (1 week to 2 weeks after onset), group B (3 to 4 weeks after onset) and group C (more than 5 weeks after onset).  The score of acute physiology and chronic health evaluation (APACHE-Ⅱ), C-reactive protein level, reoperation rate, fatality and postoperative complications, etc. were compared among the groups.
Results：The APACHE-Ⅱ score and blood C-reactive protein level of group B ［4.74±0.82, (84.81±4.65)U/L］ were significantly decreased compared with group A ［9.14±0.33, (103.40±4.40)U/L］ and group C ［8.69±0.30, (122.40±3.86)U/L］, respectively (both P＜0.01). The fatality, reoperation rate and postoperative complications of group B (6%, 27.66%, 23.40%) were significantly lower than those of the group A (12.03%, 90.32%, 51.61%) and group C (40%, 80%, 80%), respectively. (all P＜0.01).
Conclusions：The optimal timing of surgery for SAP in infection phase is 3 to 4 weeks after the onset of SAP. At that time, surgical intervention results in less postoperative complications, lower reoperation rate, and lower mortality.