What Is the Acceptable Rate of Negative Appendectomy? Comment on Prospective Evaluation of the Added Value of Imaging within the Dutch National Diagnostic Appendicitis Guideline - Do We Forget Our Clinical Eye?

To improve clinical results and resource utilization in the care of appendicitis in children, the authors examined the current practice and outcomes of 30 pediatric hospitals. The Pediatric Health Information System (PHIS) database consists of comparative data from 30 free-standing Children's hospitals. The study population of 3,393 children was derived from the database by selecting the "Diagnosis Related Group Code" for appendicitis (APRDRGv12 164), ages 0 to 17 years, using discharges between October 1, 1999 and September 30, 2000. Data are expressed as the range and median for individual hospital outcomes. The nonpositive appendectomy rate ranged from 0 to 17% at the 30 hospitals (median, 2.6%). Ruptured appendicitis varied from 20% to 76% (median, 36.5%). The median length of stay (LOS) for nonruptured appendicitis was 2 days (range, 1.4 to 3.1 days), ruptured appendicitis varied from 4.4 to 11 days (median, 6 days). The median readmission rate within 14 days was 4.3% (0 to 10%). Laparoscopic appendectomy varied from 0 to 95% in the 30 hospitals (mean, 31%) The LOS did not vary significantly in laparoscopic versus open for nonruptured (2.3 v 2.0 days) or ruptured appendicitis (5.5 v 6.2 days). Days on antibiotics for ruptured appendicitis ranged from 4.6 to 7.9 days (median, 5.9 days) Children receiving any study varied from 18% to 89% (median, 69%). Ultrasound scan and computed tomography (CT) were comparable in both nonruptured (13% ultrasound scan v 14%) and ruptured appendicitis (14% ultrasound scan v 21% CT). Significant variability in practice patterns and resource utilization exists in the management of acute appendicitis in pediatric hospitals. Clinical outcomes could be improved by collaborative initiatives to adopt evidence-based best practices. Copyright 2003, Elsevier Science (USA). All rights reserved.

INTRODUCTION The negative appendicectomy rate (NAR) is a quality metric in the management of appendicitis. While computed tomography (CT) has been associated with a low NAR, Alvarado scoring produces an acceptable NAR. The definition of negative appendicectomy may affect the NAR. This study examined the impact of CT, Alvarado score and definition on the NAR. METHODS The charts of 1,306 emergency appendicectomy patients from 1996 to 2010 were reviewed. Three five-year cohorts were created (Cohort A: 1996–2000, Cohort B: 2001–2005, Cohort C: 2006–2010) and the NAR was calculated for each cohort using two definitions of negative appendicectomy: absence of inflammation (NAR-STD) and absence of intramural neutrophils (NAR-STR). NAR-STD was correlated to the CT rate for Cohorts B and C and also to Alvarado score for Cohort C. RESULTS When the definition of negative appendicectomy was changed, the NAR rose from 9.2% to 15.8% (p=0.0097) for Cohort A, from 2.8% to 8.6% (p=0.0180) for Cohort B (CT rate: 80.6%) and from 3.0% to 6.7% (p=0.0255) for Cohort C (CT rate: 92.4%). The introduction of CT lowered NAR-STD from 1996–2000 (9.2%) to 2001–2010 (2.9%) but increasing the CT rate from 2001–2010 had no impact on the NAR. The positive predictive value for Alvarado score (98.60%) and CT (99.03%) were similar. CONCLUSIONS The definition of a negative appendicectomy determines the NAR. CT reduces the NAR regardless of definition but routine CT is unnecessary for male patients with positive Alvarado scores. Early/mild appendicitis may resolve without surgery and CT may contribute to unnecessary surgery. Alvarado scoring allows selective use of CT in suspected appendicitis.

Accurate, timely diagnosis of pediatric appendicitis minimizes unnecessary operations and treatment delays. Preoperative abdominal-pelvic computed tomography (CT) scan is sensitive and specific for appendicitis; however, concerns regarding radiation exposure in children obligate scrutiny of CT use. Here, we characterize recent preoperative imaging use and accuracy among pediatric appendectomy subjects.