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The Whole Nine Yards in Randomised Controlled Trials

2019; Elsevier BV; Volume: 59; Issue: 4 Linguagem: Inglês

10.1016/j.ejvs.2019.10.011

1532-2165

Robert Svensson‐Björk, Stefan Acosta,

Cardiac, Anesthesia and Surgical Outcomes

The article by Wübbeke et al. is the first peripheral vascular surgery randomised controlled trial (RCT) to investigate the efficacy of gentamicin implants to reduce surgical site infection (SSI) in the groin.1Wübbeke L.F. Telgenkampn B. van Boxtel T. Bolt L.J.J. Houthoofd S. Vriens P. et al.Gentamicin containing collagen implants and groin wound infections in vascular surgery: a prospective randomized controlled multicentre trial.Eur J Vasc Endovasc Surg. 2020; 59: 635-641Abstract Full Text Full Text PDF Scopus (8) Google Scholar The authors avoided investigator bias in wound assessment and used the revised criteria for wound infections established by the Centers for Disease Control and Prevention.2National Healthcare Safety Network, Centers for Disease Control and Prevention. Surgical site infection (SSI) event. Available at: http://www.cdc.gov/nhsn/pdfs/pscmanual/9pscssicurrent.pdf (accessed 3 October 2019).Google Scholar Another scientific strength was that the patients were blinded to the randomisation result. The investigators could even have used gentamicin free collagen implants in the control arm to further reduce bias. It must be said, however, that the difference in SSI rate of 22% in the control group vs. 1% in the gentamicin group at high risk centres is startling, compared with an increase in SSIs from 7% in the control group to 13% in the gentamicin group in low risk centres. This implies that there might have been difficulties in interpreting wound characteristics such as seroma formation, wound dehiscence, lymphatic leakage, and haematoma across centres. The study was funded by EUSA Pharma, UK, the manufacturer of Garacol 130 mg (gentamicin implant). Even though wound outcomes not were assessed by the investigators in charge, industry sponsorship is well known to lead to biased results and conclusions favouring the funding companies.3Lundh A. Lexchin J. Mintzes B. Schroll J.B. Bero L. Industry sponsorship and research outcome. Cochrane Database Syst Rev, 2017MR000033Crossref Scopus (501) Google Scholar The sample size calculation is realistic. However, it should be clear that patients undergoing endovascular aneurysm repair (EVAR) have a much lower groin SSI rate than those undergoing lower limb revascularisation,4Hasselmann J. Kühme T. Björk J. Acosta S. Incisional negative pressure wound therapy in the prevention of surgical site infection after vascular surgery with inguinal incisions: rationale and design of a randomized controlled trial (INVIPS-TRIAL).Surg Sci. 2015; 6: 562-571Crossref Google Scholar and it would have been preferable to exclude the 34 enrolled EVAR patients from the start. If EVAR procedures were excluded, the sample size would have been reduced. From a scientific point of view, the authors missed the opportunity to randomise patients with bilateral groin incisions to gentamicin implant in one groin and control implant in the contralateral groin, as there were 16 patients receiving an axillo- or aortobifemoral prosthesis and an unclear number of patients undergoing bilateral thrombo-endarterectomies. The advantage of including bilateral incisions is that all patient related risk factors, such as comorbidities and hygiene factors, are exactly the same in both treatment groups and patients serve as their own control.4Hasselmann J. Kühme T. Björk J. Acosta S. Incisional negative pressure wound therapy in the prevention of surgical site infection after vascular surgery with inguinal incisions: rationale and design of a randomized controlled trial (INVIPS-TRIAL).Surg Sci. 2015; 6: 562-571Crossref Google Scholar This dependency needs to be accounted for in both study design and data analysis,5Dell-Kluster S. Droeser R.A. Schäfer J. Gloy V. Ewald H. Schandelmaier S. et al.Systematic review and simulation study of ignoring clustered data in surgical trials.Br J Surg. 2018; 105: 182-191Crossref PubMed Scopus (6) Google Scholar decreasing sample size and at the same time being able to include both groins in the study. RCTs are very challenging tasks in vascular surgery, especially multicentre trials. The fact that the study ended in 2015 and was accepted for publication in 2019 highlights the logistical issues of the study. In addition, the number of patients assessed for eligibility at the four centres during the three year period should have been much higher. At the start of the study, at least one full time employee monitoring the study is necessary to be able to reach final sample size with high quality data. Even though the authors were able to include only half of the calculated sample size, their effort should be acknowledged. New RCTs in this field are warranted and some of the lessons learned from this RCT should be considered at the protocol stage. Gentamicin Containing Collagen Implants and Groin Wound Infections in Vascular Surgery: A Prospective Randomised Controlled Multicentre TrialEuropean Journal of Vascular and Endovascular SurgeryVol. 59Issue 4PreviewThe aim of this study was to assess the effectiveness of gentamicin containing collagen implants in the reduction of surgical site infections (SSIs) in patients undergoing an inguinal incision for vascular surgery. 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