Management of post appendicectomy intra-abdominal collections: A volumetric cut off for drainage?

Intra-abdominal collections (IAC) are a common complication following appendicectomy, one of the most commonly performed emergency abdominal procedures in childhood. The option to drain a collection is frequently available but not always required.

The aim of this study was to compare the outcomes of medically and procedurally-managed post appendicectomy IACs and suggest a method of standardising the need for intervention.

A single centre, retrospective review of children aged ≤ 16 years presenting between 2014 and 2019 was performed. Patient demographics, management, and outcome data were collected. IAC volume and surface area were calculated assuming a prolate spheroid or true ellipsoid depending on the number of dimensions reported.

60 patients (18%) of 334 patients developed an IAC post appendicectomy. Medical management was undertaken in 44 (73%), drainage in 12 (20%), and surgical washout in 4 (7%). Collection size was associated with failure of medical management: maximum diameter (p = 0.028), volume (p = 0.002), and surface area (p = 0.001). Collections with a volume of 2 ml/kg were significantly less likely to fail medical management than larger collections (0/33 vs 6/11; p < 0.0001).

Not all post appendicectomy IACs require drainage. The relationship between collection volume and need for drainage is more closely assessed using a volume calculation rather than a single dimension measurement, particularly when adjusted for weight of the child. A cut off of 2 ml/kg appears to be a good objective measure for intervention and provides a communication tool for discussion amongst the multidisciplinary team. Prospectively collected multicentre data on this subject would be timely.

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