The need for interval appendectomy after resolution of an appendiceal mass questioned

Background: Our current treatment of an appendiceal mass is initially conservative, followed by an interval appendectomy. The necessity of this routine interval appendectomy is debatable. A study was conducted to evaluate whether surgical factors and pathological features of the excised appendices support interval appendectomy.

Methods: We performed a retrospective study at the University Hospital Groningen and the Deventer Ziekenhuis. All patients diagnosed with an appendiceal mass in the period January 1991 to January 1997 were identified using the hospital database. The medical records of all these patients (n = 233, 108 M, 125 F) were reviewed. The clinical course of the appendiceal mass patients was split up into three distinct episodes: initial diagnosis and treatment of the appendiceal mass, the interval period and the interval appendectomy. Presenting symptoms, findings at clinical examination and additional imaging (ultrasound) were registered, as well as the course of the primary hospitalisation, the interval period, and the interval appendectomy. Results of histological examination of all resected specimens were reviewed.

Results: It was found that clinical findings alone were not specific enough to diagnose an appendiceal mass; 47% had a palpable abdominal mass and the median temperature was 38.2 degrees C ranging from 36 to 40.5 degrees C. Ultrasound examination was done in 69% of patients and showed an appendiceal mass in 72%. During the interval period, 4 patients presented with an appendiceal mass needing drainage, and 3 with acute appendicitis requiring emergency appendectomy. At interval appendectomy, histological examination of resection specimen showed a normal appendix without signs of previous inflammation in 30% of cases. In addition, complications due to interval appendectomy were seen in 18% of patients, including sepsis, bowel perforation, small bowel ileus, and various wound abscesses.

Conclusions: We conclude that when causes for the appendiceal mass other than appendicitis are excluded, interval appendectomy seems unnecessary in patients who respond well to initial conservative treatment.