SSI is associated with quality of life, increased lengths of hospital stay, so that significant benefits is expected from the prevention of SSI. The GCS was developed to reduce SSI by providing high local gentamicin concentrations but no the high systemic concentrations associated with nephrotoxicity [17]. The GCS was first approved in Germany in 1985 and is currently used in over 60 countries [14]. In view of these results, our department of surgery started to use GCS in early 2017.
However, there have been some controversies about the role of GCS. In previous study conducted on the use of GCS in reducing SSI, Musella et al.[18] examined its use in prosthetic repair of inguinal hernia and concluded that it was effective in reducing SSI. However, Anderson et al.[19], who examined the use of GCS in pilonidal sinus excision, concluded that GCS was not effective in reducing SSI. In our results, overall SSI rate for the sponge group was 13.3% (6 of 45), while SSI rate for control group was 20.1% (30 of 149); P = 0.384. With these results, we aimed to be selective in the use of GCS and to identify the subgroup of patients who would benefit most from it in our study. As Liau et al.[20] demonstrated low SSI rates for clean and clean-contaminated wounds (0% and 1.1%, respectively, from the period of 2005 to 2007), our results showed that SSI rate for these wounds were 5.9% and 14.3%, respectively. Plus, Chia et al.[21] concluded that dirty-infected wounds have the most potential for benefiting from GCS on other wound classes. However, there were only 19 patients with dirty wound in our series, so we conducted subgroup analysis combining contaminated and dirty wound together. As shown in Table 3, SSI rate for contaminated and dirty wounds were 41.7% (15 of 36) in control group and 13.6%(3 of 22) in sponge group, respectively; P = 0.04. One study demonstrated that dirty wounds carry a risk of infection in up to 45%, regardless of all measures taken to reduce the incidence of SSI, such as the improvements in surgical techniques and the use of perioperative systemic antibiotics [15].
The organisms most frequently found in SSI are the gram-negative anaerobes such as Escherichia coli, Klebsiella sp., Proteus mb and Pseudomonas aeruginosa, among others; therefore aminoglycosides should be included in the treatment regimens for the SSI [16, 22]. For gentamicin, a positive influence on anastomotic healing and the quality of collagen formation could be shown [23], whereas Bang et al.[24] reported GCS hampering epithelialization and neovascularization in a mouse model. Vaneerdeweg et al.[24] set up a rat model in which nearly all rats in the collagen group developed anastomotic breakdowns. However, there were no cases of wound disruption or incisional hernia in both groups during the study periods.
In our results, the length of hospital stay was not different between two group (18.43 ± 20.89 versus 19.91 ± 14.47; P = 0.665). But Sponge group was consisted relatively large proportion of contaminated and dirty wound rather than control group that means sponge group is consisted with more severe patients compared to control group.
It has been well known that immediate closure of contaminated or dirty abdominal wounds at the time of surgery increases the risk of SSI. The most frequent method for preventing SSI consists in leaving the wound open and closing it within 3 to 5 days. However this make the patients feel severe pain during the wound dressing until wound is closed and it is associated with increased length of hospital stay. Therefore, the GCS is more comfortable and effective rather than delayed wound closure.
This study has several limits. First one is that this is retrospective study. Also the use of GCS was determined by surgeon’s preferences. Finally, we used only 1 size of GCS in this study, however, previous study demonstrated that larger size of GCS is more effective related to the size of wound [21]. Randomized controlled trial using several sizes of GCS is needed in the future.