The medical records for a total of 71 patients were reviewed in the study. No power calculations were reported. One centre ('alpha' centre) used a designated team (n=27) whereas the other ('beta' centre, n=44) used a nondedicated team. 35 cases (23 at the alpha site, 12 at the beta site) and 36 cases (11 alpha, 25 beta), respectively, were performed by the advanced and basic surgeon.