The frequency of surgical site infections (SSIs) after clean neck surgery is low and antibiotic prophylaxis is not recommended. This retrospective study investigated the effect of perioperative prophylactic antimicrobial therapy on the development of infections. A total of 807 consecutive patients undergoing clean neck surgery were included in the study. Antimicrobial prophylaxis with intravenous cefuroxime was administered in 518 cases. Although patients who received prophylaxis had a lower rate of SSIs than those who did not receive antibiotics, this was not statistically significant (0.4% vs 1.4% respectively, p=0.19). Older age was the only variable associated with the development of SSIs (p=0.014). Clean neck operations (thyroidectomy, parathyroidectomy and lymph node resection) are among the most common operations performed worldwide. Most guidelines do not recommend the routine use of perioperative antimicrobial prophylaxis for these procedures 1,2 because the frequency of surgical site infections (SSIs) is generally low (<1%).3,4 However, prophylaxis is still often used in these cases as some surgeons and anaesthetists feel that this advice is not appropriate for a part of the globe in which multidrug resistant infections are endemic. In this context, we studied the frequency of postoperative infections after clean neck surgery and examined the effect of perioperative prophylactic antimicrobial therapy on the development of infections. MethodsThis was an observational, retrospective study performed in a 140-bed private clinic (Department of Endocrine Surgery, Central Clinic) in Athens, Greece, over a 5-year period (2010)(2011)(2012)(2013)(2014). The study was approved by the clinic's ethics committee. All patients undergoing clean neck surgery (regardless of age, sex and co-morbidity) were included. All operations were performed by the same primary surgeon and surgical team. Apart from the primary operator, there were also three assistants and one of two anaesthetists. Administration of perioperative prophylaxis was at the discretion of the anaesthetist. The first anaesthetist did not provide antibiotic prophylaxis in any patient while the second administered antibiotics to all patients. Selection of the anaesthetist was independent of patient characteristics and operation plan. All data were retrieved from patient files. The patients were divided into two groups based on whether antimicrobial prophylaxis was administered. Among the patients in the antibiotics cohort, only those who received intravenous cefuroxime were studied. The primary outcome was the rate of SSIs or remote infections. Statistical analysis ResultsDuring the study period, 849 patients underwent surgery. Of these, 34 were excluded because data were missing, 7410 Ann R Coll Surg Engl 2017; 99: 410-412