This study found a median operative time of the initial debridement for NSTIs of 59 min, with most of the debridements (78%) lasting no longer than 90 min and an overall 30-day mortality rate of 14% in NSTI patients who underwent at least one debridement. Greater estimated TBSA affected and a higher ASA classification were independently associated with increased mortality, while the operative time did not demonstrate a direct relation with mortality, however the fifteen patients (9%) who underwent surgery for > 140 min had a two-fold increase in mortality. Multivariate analysis showed that each 20 min of extra operative time during the initial debridement resulted in a 1.4-day increase in ICU stay and 3.3-days increase in hospital stay, even if corrected for the presence of sepsis prior to the surgery, estimated TBSA affected and ASA classification.
No other study has investigated the association between the operative time of the initial debridement for NSTIs and its outcomes. However, three prior studies have reported the mean operative time for their entire NSTI cohort. Hong et al. reported an mortality rate of 60% for fifteen septic Vibrio NSTI patient with all a NSTI affecting the extremities, which was associated with a mean duration of the initial debridement of 102 min [5]. Corman et al. found a mortality rate of 4% for Fournier gangrene with an associated mean duration of the initial surgery of 78 min and Elsaket et al. reported an mortality rate of 11.4% for Fournier gangrene associated with a mean duration of the initial debridement of 81 min [4, 6]. Notable, all patients underwent a scrotectomy for source control in the study by Corman et al. and in the study by Elsaket et al. only 5% of the patients were septic upon presentation. As a result, and combined with the fact that those studies only investigated specific NSTI subtypes, these studies cannot directly be compared to our study which consisted of a heterogeneous population with mainly GAS infections in non-Fournier regions as we know that certain pathogens causing NSTIs tend to be associated with higher mortality rates, such as polymicrobial and Vibrio NSTIs [20]. Nonetheless, there is a shorter median operative time in this current cohort, with only 22% of the patients undergoing initial debridements for over 90 min.
As seen in this study, NSTI patients often undergo surgery while they are physiologically compromised (e.g. metabolic acidosis, high sepsis scores), therefore it was postulated that these patients could also benefit from the damage control principles. The concept of damage control was first established to improve outcomes of severely injured trauma patients by obtaining rapid hemorrhage control and prevent contamination without definitive repairs during the first surgery, followed by resuscitation in attempt to prevent and/or reverse the pathophysiological triad of coagulopathy, metabolic acidosis and hypothermia (“lethal triad”) [21]. Definitive surgical repair was reserved until after the goals of resuscitation were reached. In this study reduced operative times were not associated with a reduction in mortality, however, since this study is underpowered for this association, the hypothesis cannot yet be rejected nor confirmed. The lack of mortality reduction might be caused by the fact that the patients included in our study almost all had already a relatively short, and therefore already optimized, operating time. On the other hand, the reduced operative times were indeed associated with a significant shorter ICU and hospital stays, regardless of the presence of sepsis prior to surgery, the estimated TBSA affected and the ASA classification. The concept of reducing length of ICU and hospital stay by reducing operative times has not yet been described for NSTIs, but has been suggested for surgical procedures in trauma and general surgery [8, 22]. Procter et al. studied general surgical procedures and found that the odds ratio for ICU admission, adjusted for operative and patient risk variables, increased with 0.32 each half-hour of extra operative time and the hospital length of stay increased with 6% with each half hour extra operative time [8]. Harvin et al. studied emergency trauma laparotomies and found that damage control principles when applied correctly significantly increased the probability of a shorter ICU and hospital stay compared to when a definitive laparotomies was performed [22]. Furthermore, this study showed that besides operative time, sepsis prior to surgery is also independently associated with prolonged ICU and hospital stay, however this variable is often non-modifiable.
The principle of damage control is based on the philosophy of doing only what is necessary in order not to exhaust the physiological reserves of the patient. Therefore, it can be questioned if performing debridement utilizing the skin sparing technique for NSTIs is doing something more than necessary [23]. In the current study, the skin sparing technique did not result in median prolonged operative times, which might indicate that the technique was used in the proper cases. Nevertheless, a case of 400 min was documented with fatal outcome.
The use of intra-operative diagnostics such as frozen section or Gram stain have also been argued to cause treatment delay, since the time waiting on the results could also be used for debridement, however this statement was not yet investigated in a clinical study [24, 25]. This study found indeed a prolonged operative time with a difference in medians of 41 min, which is to be expected since it can take up to 30 min to process and assess a frozen section [12, 13]. However, the time to diagnosis was significantly shorter in cases that used intra-operative diagnostics (difference in medians of 3 h), which enables timely debridement. However, these intra-operative diagnostic modalities should only be used if indicated: in ambivalent cases to prevent unnecessary debridements in non-NSTI cases or prevent delay and/or refrainment of debridement due to less evident macroscopic findings in NSTI cases [26].
The findings of this study need to be interpreted in context of its limitations. First, the retrospective nature of this study resulted in a substantial amount of missing dating for certain variables, especially limiting our ability to use blood gasses results to calculate SOFA and APACHE II scores and to determine the degree of sepsis/septic shock. Especially for these variables, selection bias is likely present, because patient presenting without systemic toxicity will not always have a comprehensive laboratory work-up. Second, the TBSA was estimated based on operative notes and might be over- or underestimated in certain patients. Third, other factors associated with mortality (such as pathogen or time to surgery) could not reliably be investigated in this study, since only patients undergoing surgery were included and it is known that is common that some patients with NSTIs are already deceased before they can undergo surgery. Furthermore, this study is underpowered regarding the main objective, this warrants further research in bigger cohorts. However, the strengths of this study are the fairly large sample size compared to other NSTI cohorts and that it is the first study assessing the consequences of prolonged operative times of the initial debridement for NSTIs.