Antibiotics and postoperative abscesses in complicated appendicitis: is there any association?

INTRODUCTION: Complicated appendicitis has significant infective postoperative morbidity. There is no universally-accepted antibiotic regime, although traditionally, triple antibiotics are recommended. Our complicated appendicitis clinical pathway recommends ceftriaxone and metronidazole. The study aimed to determine if choice of antibiotics influenced the risk of infective complications.
METHODS: We reviewed all paediatric appendicectomy patients between January 1, 2005 and December 31, 2005. All patients with intraoperative diagnosis of perforated appendicitis were recruited, excluding infants, immunocompromised patients, and patients allergic to the guideline antibiotics. All operations were performed by registrar/consultant surgeons and were laparoscopic, unless technically not feasible.
RESULTS: There were 82 patients with perforated appendicitis. 62 patients (76 percent) followed pathway antibiotics, and 20 patients (24 percent) deviated from the pathway by receiving additional empiric gentamycin. We compared the pathway compliant and deviation groups, and found no significant differences in patient characteristics, clinical presentation, operation, length of stay and infective complications. Overall there was one wound infection and five (six percent) postoperative abscesses. Initial peritoneal cultures and subsequent drainage cultures of patients who developed abscesses were sensitive to treatment antibiotics.
CONCLUSION: In complicated appendicitis, empirical perioperative addition of gentamycin to ceftriaxone and metronidazole did not reduce the risk of developing intra-abdominal abscess, compared to changing antibiotics on clinical grounds. Patients developed postoperative abscesses despite initial peritoneal cultures growing organisms sensitive to treatment antibiotics.