C. Maloney1, M. C. Edelman2, A. C. Bolognese1, L. Collins3, A. M. Lipskar1, B. S. Rich1 1Hoftstra Northwell School Of Medicine,Surgery,New Hyde Park, NY, USA 2Hofstra Northwell School Of Medicine,Pathology And Laboratory Medicine,New Hyde Park, NY, USA 3Hoftstra Northwell School Of Medicine,Pediatric Radiology,New Hyde Park, NY, USA
Introduction: Negative appendectomy rate (NAR) is a quality metric used in the surgical management of appendicitis. An acceptable NAR minimizes the morbidity of missed appendicitis, which is typically higher than that of non-therapeutic appendectomy. The rates of negative appendectomy (NA) in children range from 5-40% in the literature. Many reports do not provide a clear pathological definition of acute appendicitis or NA. In order to interpret these data, a generalizable definition of a normal appendix must be accepted. We reviewed our experience with pediatric appendectomy and the pathological spectrum encompassed within our definition of a NA and examined how the definition impacts our hospital’s NAR.
Methods: A retrospective review from 2012-2016 identified 1,676 children that underwent appendectomy. Average age was 11.4 (4-18 yo). Interval and incidental appendectomies were excluded. Patient demographics, perioperative data and pathological findings were collected. Appendicitis was defined as the presence of transmural aucte inflammation in the appendix while NA was defined as the absence of transmural inflammation.
Results: 1,437 patients underwent appendectomy for presumed appendicitis. The rate of pathologically diagnosed appendicitis was 91%(1,318/1437). Using the proposed definition of NA, NAR was 8.4% (120/1437). 60% of patients with true appendicitis presented with vomiting vs 38.5% of NA patients (p<0.01). The average white blood cell count was 11.3 ± 4.8 in the NA group vs 15.5 ± 5.3 in the patients with true appendicitis (p<0.001). 88.3% of NA patients were diagnosed with ultrasound alone and 27.5% with CT scan. 11.6% of NA patients had mesenteric lymphadenopathy on US vs 3% of patients with true appendicitis (p<0.05). Review of the pathology of the NA cohort identified 61/120(50.8%) patients with completely normal pathology. The remaining 59 (50.4%) patients displayed some sort of pathological abnormality including fecaliths (n=9), pinworms (n= 3), cryptitis (n=10), granuloma (n=2), fibrous obliteration of the appendiceal tip (n=4), lymphadenopathy (n=1), and non-specific inflammation (n=30). Exclusion of these patients decreased the NAR to 4.2%. Subgroup analysis could not identify pre-operative factors that differentiated the patients with normal pathology from those with pathological abnormalities. Of the NA patients, 5(4.2%) were readmitted for recurrent abdominal pain (2 with normal pathology and 3 with abnormal pathology).
Conclusion: Pediatric NAR is dependent upon the pathological definitions of a normal appendix and variations in definition may explain discrepancies in the literature. Changing our definition of a NA to “the absence of inflammation or other appendiceal pathology” decreased the negative appendectomy rate by 50%. Further follow-up of patients with pathological abnormalities other than transmural inflammation is warranted to determine the necessity for surgery in this group.