Necrotizing fasciitis: microbiological characteristics and predictors of postoperative outcome

Abstract

Objective: Necrotizing fasciitis is a life threatening soft-tissue infection with a high morbidity and mortality. Prompt treatment based on extensive surgical debridement and antibiotic therapies are the therapeutic principles.

Methods: The medical records of patients with necrotizing fasciitis (n = 26) from 1996 to 2005 were retrospectively analyzed.

Results: The localization of necrotizing fasciitis was most commonly the trunk (42.3 %). Type I polymicrobial infection was the dominating infection. The involvement of anaerobic bacteria was associated with an increase in the number of surgical revisions (p = 0.005). Length of postoperative intensive care unit stay, duration of postoperative ventilation and mortality were significantly increased in the ASA IV-V group. Computed tomography displayed only a limited significance as diagnostic tool for initial diagnosis.

Conclusions: In severe cases the combination of necrotic skin and soft tissue gas facilitates the correct diagnosis, which should than be followed by immediate - and most often - repeated debridement. If anaerobes are isolated an early and aggressive second look is necessary.

Figure 1

Localization of necrotizing fasciitis.

Figure 2

Morphological aspects of necrotizing fasciitis. Typical aspects on computed tomography (CT) scan included a thickening of the fascial layer, stranding of the subcutaneous tissue as well as edema of the adjacent muscle and local gas collections. (B) Histological hallmarks of necrotizing fasciitis with subcutaneous (a) and fascial (b) necrosis. (C) Intraoperative typical appearance of necrotic fascial layer and surrounding inflammatory tissue.

Figure 3

Definitive reconstructions after successful treatment of necrotizing fasciitis.

Figure 4

Relationship between number of surgical revisions and existence of anerobic bacterial strains (p = 0.005; Mann-Whitney-test).

Figure 5

Prognostic impact of the classification according the American Society of Anaesthesiologists (ASA) and course of disease. ASA IV and V patients had to be (A) ventilated for a longer period (p = 0.003) and (B) required a longer intensive care unit (ICU) stay (p = 0.009).

Figure 6

Relationship between the classification according American Society of Anaesthesiologists (ASA) and mortality While none of the patients classified as ASA II-III died, mortality in patients with ASA IV-V was 50%. (p = 0.036; Mann-Whitney-test).