The association of elevated percent bands on admission with failure and complications of interval appendectomy.

Background/purpose: The routine use of interval appendectomy for the treatment of perforated appendicitis, with or without abscess, remains controversial. The purpose of this study is to confirm the efficacy of this approach and to identify factors associated with failures and complications.
Methods: All patients (n = 101) with their clinical diagnosis of perforated appendicitis confirmed with imaging were treated prospectively with fluids and intravenous antibiotics (clindamycin, ceftazidime) and were discharged home on oral fluids and analgesics regardless of fever. Intravenous antibiotics were continued at home until the patients were afebrile for 48 hours, and their white blood cell and differential counts were normal. Patients were readmitted at 8 to 12 weeks for an interval appendectomy. Failure to improve by 72 hours of antibiotic therapy mandated an early appendectomy. P values were determined by chi(2) analysis and Student's t test.
Results: The 79 patients (78%) successfully treated with interval appendectomy had an overall 6.3% complication rate, and total hospitalization averaged 5.2 days. The treatment in 21 of 22 patients (22%) requiring early appendectomy failed because of a clinical picture suggesting small bowel obstruction. The patients with the failed procedures had a complication rate of 50% and were hospitalized an average of 12.8 days. The overall complication rate for the 101 patients was 15.8%, and the overall total hospitalization was 6.9 days. Patients requiring early appendectomy had a more frequent finding resembling a small bowel obstruction on their initial x-ray (50% v 13%, P = .004) and a higher percent band count on their initial differential blood cell count (22.6% v 7.6%, P<0.0001) than did those successfully treated with interval appendectomy. An initial band count <15% was predictive of an uncomplicated course (84% positive predictive value).
Conclusions: Interval appendectomy without complications is successful in the majority of patients with perforated appendicitis. An elevated initial band count > or =15% is associated with an increased likelihood of failure and complications.