There were no statistically significant differences between the HA/CMC powder group and the no adhesion barrier group in SSIs ( 21 % vs. 14 % ; P = 0.216 ) and serious SSIs ( 12 % vs. 9 % ; P = 0.38 ) , or in the most frequent serious SSIs of pelvic abscess ( 5 % and 2 % ; significance not tested ) , anastomotic fistula ( 3 % and 4 % ) , and peritonitis ( 2 % and 3 % ) .