To whom do the results of the multicenter, randomized, controlled INSECT trial (ISRCTN 24023541) apply?--assessment of external validity.

UNLABELLED: A response to Seiler et al: Interrupted or continuous slowly absorbable sutures for closure of primary elective midline abdominal incisions: a multicenter randomized trial (INSECT: ISRCTN24023541). Ann Surg 2009, 249(4):576-582. BACKGROUND: Existing evidence suggests that the transfer of results of randomized controlled trials into clinical practice may be limited. Potential reasons can be attributed to aspects of external validity. The aim of this study is to investigate issues related to the external validity of the INSECT trial. METHODS: All participating surgical departments were categorized and the clinical and baseline characteristics of randomized patients were evaluated. In addition, demographic and clinical data of all screened and randomized patients at the Departments of Surgery in Heidelberg and Erlangen were analyzed. RESULTS: Twenty-five centers enrolled a total of 625 patients. These centers included eight primary, 11 secondary, and six tertiary care centers. The tertiary care centers enrolled the most patients (n = 237, 38%) followed by the primary care centers (n = 199, 32%) and the secondary care centers (n = 189 patients; 30%). The mean number and baseline data of randomized patients did not differ between the three types of care centers (p = 0.09). Overall, the treatment according to protocol was at least 92%. At the Department of Surgery, University of Heidelberg, 307 patients were screened and 60 out of 130 eligible patients were randomized. There were no differences in demographic and clinical baseline data between included and non-included patients. In Erlangen, 351 patients were screened and 57 out of 106 eligible patients randomized. CONCLUSIONS: Results of the INSECT trial are applicable to a broad spectrum of patients treated at different hospital levels.

Risk-benefit assessment of closed intra-abdominal drains after pancreatic surgery: a systematic review and meta-analysis assessing the current state of evidence.

BACKGROUND: This systematic review aims to analyse the risk-benefit association of (1) prophylactic drains and/or (2) the time of their removal after pancreatic resection. MATERIALS AND METHODS: A systematic literature search (Medline, Embase, Biosis, and The Cochrane Library) was performed to identify all types of controlled trials comparing the role of drainage or the time of their removal on postoperative complications following pancreatic surgery. Meta-analysis was performed using a random-effects model. RESULTS: Four studies, two randomised trials and two prospective cohort studies, were included in the systematic review and meta-analysis. Removal of drains at day 5 or later did not show an influence on mortality, morbidity, re-intervention or hospital stay compared to no insertion of drains. Early (day 3-4) compared to late (≥ day 5) drain removal significantly reduced pancreatic fistulas (odds ratio (OR) 0.13; 95% confidence interval (CI) 0.03-0.32; P = 0.0002), intra-abdominal collections (OR 0.08; 95% CI 0.01-0.67; P = 0.02) and abscesses (OR 0.26; 95% CI 0.07-1.00; P = 0.05). Moreover, hospital stay was significantly reduced after early drain removal (mean difference -2.60 days; 95% CI -4.74 to -0.46; P = 0.02) CONCLUSION: Further randomised controlled trials are warranted to clarify whether drains are of any use. In case of drain insertion, early removal seems to be superior to late removal.

Evaluation and stages of surgical innovations.

Surgical innovation is an important part of surgical practice. Its assessment is complex because of idiosyncrasies related to surgical practice, but necessary so that introduction and adoption of surgical innovations can derive from evidence-based principles rather than trial and error. A regulatory framework is also desirable to protect patients against the potential harms of any novel procedure. In this first of three Series papers on surgical innovation and evaluation, we propose a five-stage paradigm to describe the development of innovative surgical procedures.

No surgical innovation without evaluation: the IDEAL recommendations.

Surgery and other invasive therapies are complex interventions, the assessment of which is challenged by factors that depend on operator, team, and setting, such as learning curves, quality variations, and perception of equipoise. We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process. We also encourage the widespread use of prospective databases and registries. Reports of new techniques should be registered as a professional duty, anonymously if necessary when outcomes are adverse. Case series studies should be replaced by prospective development studies for early technical modifications and by prospective research databases for later pre-trial evaluation. Protocols for these studies should be registered publicly. Statistical process control techniques can be useful in both early and late assessment. Randomised trials should be used whenever possible to investigate efficacy, but adequate pre-trial data are essential to allow power calculations, clarify the definition and indications of the intervention, and develop quality measures. Difficulties in doing randomised clinical trials should be addressed by measures to evaluate learning curves and alleviate equipoise problems. Alternative prospective designs, such as interrupted time series studies, should be used when randomised trials are not feasible. Established procedures should be monitored with prospective databases to analyse outcome variations and to identify late and rare events. Achievement of improved design, conduct, and reporting of surgical research will need concerted action by editors, funders of health care and research, regulatory bodies, and professional societies.

Challenges in evaluating surgical innovation.

Research on surgical interventions is associated with several methodological and practical challenges of which few, if any, apply only to surgery. However, surgical evaluation is especially demanding because many of these challenges coincide. In this report, the second of three on surgical innovation and evaluation, we discuss obstacles related to the study design of randomised controlled trials and non-randomised studies assessing surgical interventions. We also describe the issues related to the nature of surgical procedures-for example, their complexity, surgeon-related factors, and the range of outcomes. Although difficult, surgical evaluation is achievable and necessary. Solutions tailored to surgical research and a framework for generating evidence on which to base surgical practice are essential.