Incidence and locations of intra-abdominal abscesses after laparoscopic vs. open appendectomy; role of pneumoperitoneum and abdominal irrigation.

In the Netherlands, 16.000 appendectomies are performed annually. The proportion laparoscopic appendectomies (LA) is increasing compared to open appendectomies (OA), because of its advantages. However, an important disadvantage of LA is the increased abscess rate (LA 1.6% versus OA 0.6%). Intra-abdominal bacterial dissemination due to pneumoperitoneum or abdominal irrigation might play a role. This could result in abscess formation in other regions of the abdomen, and not only locally in the right iliac fossa. Therefore, the aim of this study is to analyze the role of pneumoperitoneum and abdominal irrigation in abscess formation, by evaluating abscess locations. After retrospective analysis of all patients who underwent appendectomy from 1991 until 2011 (n=2726), 263 patients had suspicion for abscess formation. Wound abscesses were excluded. Intra-abdominal abscesses were present in 83 patients, 3.6% after LA (n=63), and 2.2% after OA (n=20), p = 0.042. Of all abscesses, 24.1% was found in the right iliac fossa (n=20), and 75.9% was found in other regions of the abdomen (n=63). Abscess locations were not related significantly to the operation technique, p = 0.377. In 201/263 patients (76.4%) abdominal irrigation was applied. Of all patients with abscesses, 86.7% received abdominal irrigation, p = 0.003. Of all irrigated patients who developed an abscess, abscesses were significantly more located in other regions of the abdomen, p = 0.001. This retrospective study shows that the abscess rate after laparoscopic appendectomy is significantly higher compared to open appendectomy. Pneumoperitoneum is not associated with abscess formation in other regions of the abdomen. Abdominal irrigation appears to have no preventive effect on abscess formation, it may even contribute to abscess formation in other regions.