Recent evidence for subcutaneous drains to prevent surgical site infections after abdominal surgery:A systematic review and metaanalysis

BACKGROUND Surgical site infections(SSIs)increase mortality,hospital stays,additional medical treatment,and medical costs.Subcutaneous drains prevent SSIs in gynecological and breast surgeries;however,their clinical impact in abdominal surgery remains unclear.AIM To investigate whether subcutaneous drains were beneficial in abdominal surgery using a systematic review and meta-analysis.METHODS The database search used PubMed,MEDLINE,and the Cochrane Library.The following inclusion criteria were set for the systematic review:(1)Randomized controlled trial studies comparing SSIs after abdominal surgery with or without subcutaneous drains;and(2)Studies that described clinical outcomes,such as SSIs,seroma formation,the length of hospital stays,and mortality.RESULTS Eight studies were included in this meta-analysis.The rate of total SSIs was significantly lower in the drained group(54/771,7.0%)than in the control group(89/759,11.7%),particularly in gastrointestinal surgery.Furthermore,the rate of superficial SSIs was slightly lower in the drained group(31/517,6.0%)than in the control group(49/521,9.4%).No significant differences were observed in seroma formation between the groups.Hospital stays were shorter in the drained group than in the control group.CONCLUSION Subcutaneous drains after abdominal surgery prevented SSIs and reduced hospital stays but did not significantly affect seroma formation.The timing of drain removal needs to be reconsidered in future studies.

Scoring criteria for determining the safety of liver resection for malignant liver tumors

BACKGROUND Liver resection has become safer as it has become less invasive.However,the minimum residual liver volume(RLV)required to maintain homeostasis is unclear.Furthermore,the formulae used to calculate standard liver volume(SLV)are complex.AIM To review previously reported SLV formulae and the methods used to evaluate the minimum RLV,and explore the association between liver volume and mortality.METHODS A systematic review of Medline,PubMed,and grey literature was performed.References in the retrieved articles were cross-checked manually to obtain further studies.The last search was conducted on January 20,2019.We developed an SLV formula using data for 86 consecutive patients who underwent hepatectomy at our institution between July 2009 and August 2011.RESULTS Linear regression analysis revealed the following formula:SLV(mL)=822.7×body surface area(BSA)?183.2(R2=0.419 and R=0.644,P<0.001).We retrieved 25 studies relating to SLV formulae and 12 studies about the RLV required for safe liver resection.Although the previously reported formulae included various coefficient and constant values,a simplified version of the SLV,the common SLV(cSLV),can be calculated as follows:cSLV(mL)=710 or 770×BSA.The minimum RLV for normal and damaged livers ranged from 20%-40%and 30%-50%,respectively.The Sapporo score indicated that the minimum RLV ranges from 35%-95%depending on liver function.CONCLUSION We reviewed SLV formulae and the minimum RLV required for safe liver resection.The Sapporo score is the only liver function-based method for determining the minimum RLV.