The need for registries in the early scientific evaluation of surgical innovations

Asafield,surgeryhasgeneratedsomeof theleading innovators in history (1).Advancesin immunology and microbiology knowl-edge and exciting technological develop-ments, e.g., 3D imaging, robotic surgery,natural orifice transluminal endoscopicsurgery, tissue engineering, and 3D print-ing, will maintain the innovation potentialin the field of surgery on a high level.Randomized controlled trials (RCTs)represent the gold standard for evalua-tion of the safety and efficacy of surgi-cal interventions. There are several fac-tors that make conduct of RCTs of surgi-cal procedures particularly difficult. There-fore in the past the majority of surgicalinnovations were accepted on the basis ofnon-randomized trials (2).That was highlighted, in particular, bythe reaction to the introduction of laparo-scopic cholecystectomy, which was greetedby Sir Alfred Cushieri as the “greatestunaudited procedure in the history ofsurgery”(3).The first minimally invasivegallbladder-removal procedure was per-formed by Muhe in Germany in 1985 usinga galloscope he himself had designed (4),and the first video-endoscopic cholecystec-tomy was carried out by Mouret in Francein 1987 (3). The first case series was thenpublished by Dubois in 1989 with 63 cases(5), and by Perissat in 1992 with 777 cases(6). By that time, laparoscopic cholecys-tectomy had already become established inmany hospitals worldwide. A problematicissue during that phase of“scientific uncer-tainty” was the significantly higher rateof common bile duct injuries, especiallyduring the learning curve (7).The first report on a prospective ran-domizedtrialcomparinglaparoscopicwithopen cholecystectomy were published in1992, attesting to the benefits of the mini-mally invasive technique (8). However, thesample size in that first RCT was only70 patients. It was only in 2006, whenthe Cochrane Collaboration reviewed ina meta-analysis of 38 RCTs with 2,338patients, i.e., on average 62 patients perstudy,that itwaspossibleto issueascientif-ically corroborated statement demonstrat-ing that laparoscopic cholecystectomy didnotdifferfromtheopentechniqueintermsof mortality, complication rate, or operat-ing time,but did result in a shorter hospitalstay and quicker convalescence (9).The authors thus concluded that “theseresults confirm the existing preferencefor the laparoscopic cholecystectomy overopen cholecystectomy.”It thus took 20years from the initialintroduction of video-endoscopic chole-cystectomy until scientific proof of itsbenefits to the patients could be demon-strated. That proof, of the highest levelof evidence according to the Oxford cri-teria, was obtained from the RCT goldstandard and meta-analysis. By that time,laparoscopic cholecystectomy had alreadybecome established as the gold standard inall hospitals worldwide.As a reaction to the analysis of howinnovations were taking place in surgery,an expert group was set up within theframework of the Balliol Collaborationto compile recommendations for scientificevaluation of surgical innovations. In thatspirit, McCulloch (10) stated that “in theshort term, we cannot change how surgicalinnovations happen and so we need toadapt our methods to the process ratherthan doing the opposite.”In addition, the Balliol Collaborationhighlighted the special features of this sur-gical innovation process:“By contrast withthe formalized approach for drug devel-opments, the process in surgery has beenunregulated, unstructured, and variable.Surgery and other invasive therapies arecomplex interventions, the assessment ofwhich is challenged by factors that dependon operator, team, and setting, such aslearning curves, quality variations, andperception of equipoise”(10).To take account of how surgical inno-vations take place in reality, the BalliolCollaboration recommends that details ofpatients treated with the new techniquebe recorded in prospective developmentstudies, prospective research databases, orprospective registries. These prospectivelyrecorded data will provide for a betterpowercalculationforRCTs,indicationscanbe formulated for this new technique andquality criteria identified (10). As such,prospectively recorded registry data canplay an important role in the developmentof high-caliber RCTs since the prospec-tive registry data can pave the way for anenhanced study design for RCTs. In partic-ular, this would cut back on the need forRCTs with a relatively small sample size,while reserving resources for those RCTsendowed with adequate power.A good example of early scientific eval-uation of surgical innovation by meansof a prospective research database is theNOTES registry of the German Societyof General and Visceral Surgery. Data onall procedures related to natural orifices(transgastral, transrectal, and transvagi-nal) can be entered into the registry forNatural Orifice Transluminal EndoscopicSurgery. The national NOTES registry wasset up by the German Society of Gen-eral and Visceral Surgery to collect dataon implementation of the new technique.The aim is to draw on past experiences