Systematic review of the quantity and quality of randomized clinical trials in pancreatic surgery.

BACKGROUND: RCTs are considered the reference standard in clinical research. However, surgical RCTs pose specific challenges and therefore numbers have been lower than those for randomized trials of medical interventions. In addition, surgical trials have often been associated with poor methodological quality. The objective of this study was to evaluate the evolution of quantity and quality of RCTs in pancreatic surgery and to identify evidence gaps. METHODS: PubMed, CENTRAL and Web of Science were searched systematically. Predefined data were extracted and organized in a database. Quantity and quality were compared for three intervals of the study period comprising more than three decades. Evidence maps were constructed to identify gaps in evidence. RESULTS: The search yielded 8210 results, of which 246 trials containing data on 26 154 patients were finally included. The number of RCTs per year increased continuously from a mean of 2·8, to 5·7 and up to 13·1 per year over the three intervals of the study. Most trials were conducted in Europe (46·3 per cent), followed by Asia (35·0 per cent) and North America (14·2 per cent). Overall, the quality of RCTs was moderate; however, with the exception of blinding, all domains of the Cochrane risk-of-bias tool improved significantly in the later part of the study. Evidence maps showed lack of evidence from RCTs for operations other than pancreatoduodenectomy and for specific diseases such as neuroendocrine neoplasms or intraductal papillary mucinous neoplasms. CONCLUSION: The quantity and quality of RCTs in pancreatic surgery have increased. Evidence mapping showed gaps for specific procedures and diseases, indicating priorities for future research.

Network meta-analysis of topical haemostatic agents in thyroid surgery.

BACKGROUND: The objective of this study was to investigate the potential benefit of local haemostatic agents for the prevention of postoperative bleeding after thyroidectomy. METHODS: A systematic literature search was performed, and RCTs involving adult patients who underwent thyroid surgery using either active (AHA) or passive (PHA) haemostatic agents were included in the review. The main outcome was the rate of cervical haematoma that required reoperation. A Bayesian random-effects model was used for network meta-analysis with minimally informative prior distributions. RESULTS: Thirteen RCTs were included. The rate of cervical haematoma requiring reoperation ranged from 0 to 9·1 per cent, and was not reduced by haemostatic agents: AHA versus control (odds ratio (OR) 1·53, 95 per cent credibility interval 0·21 to 10·77); PHA versus control (OR 2·74, 0·41 to 16·62) and AHA versus PHA (OR 1·77, 0·12 to 25·06). No difference was observed in the time required for drain removal, duration of hospital stay, and the rate of postoperative hypocalcaemia or recurrent nerve palsy. AHA led to a significantly lower total postoperative blood loss and reduced operating time in comparison with both the control and PHA groups. CONCLUSION: The general use of local haemostatic agents has not been shown to reduce the rate of clinically relevant bleeding.

Meta-analysis of prophylactic abdominal drainage in pancreatic surgery.

BACKGROUND: Intra-abdominal drains are frequently used after pancreatic surgery whereas their benefit in other gastrointestinal operations has been questioned. The objective of this meta-analysis was to compare abdominal drainage with no drainage after pancreatic surgery. METHODS: PubMed, the Cochrane Library and Web of Science electronic databases were searched systematically to identify RCTs comparing abdominal drainage with no drainage after pancreatic surgery. Two independent reviewers critically appraised the studies and extracted data. Meta-analyses were performed using a random-effects model. Odds ratios (ORs) were calculated to aggregate dichotomous outcomes, and weighted mean differences for continuous outcomes. Summary effect measures were presented together with their 95 per cent confidence intervals. RESULTS: Some 711 patients from three RCTs were included. The 30-day mortality rate was 2·0 per cent in the drain group versus 3·4 per cent after no drainage (OR 0·68, 95 per cent c.i. 0·26 to 1·79; P = 0·43). The morbidity rate was 65·6 per cent in the drain group and 62·0 per cent in the no-drain group (OR 1·17, 0·86 to 1·60; P = 0·31). Clinically relevant pancreatic fistulas were seen in 11·5 per cent of patients in the drain group and 9·5 per cent in the no-drain group. Reinterventions, intra-abdominal abscesses and duration of hospital stay also showed no significant difference between the two groups. CONCLUSION: Pancreatic resection with, or without abdominal drainage results in similar rates of mortality, morbidity and reintervention.

Meta-analysis of immunonutrition in major abdominal surgery.

BACKGROUND: The objective of this study was to evaluate the potential benefits of immunonutrition in major abdominal surgery with special regard to subgroups and influence of bias. METHODS: A systematic literature search from January 1985 to July 2015 was performed in MEDLINE, Embase and CENTRAL. Only RCTs investigating immunonutrition in major abdominal surgery were included. Outcomes evaluated were mortality, overall complications, infectious complications and length of hospital stay. The influence of different domains of bias was evaluated in sensitivity analyses. Evidence was rated according to the GRADE Working Group grading of evidence. RESULTS: A total of 83 RCTs with 7116 patients were included. Mortality was not altered by immunonutrition. Taking all trials into account, immunonutrition reduced overall complications (odds ratio (OR) 0·79, 95 per cent c.i. 0·66 to 0·94; P = 0·01), infectious complications (OR 0·58, 0·51 to 0·66; P < 0·001) and shortened hospital stay (mean difference -1·79 (95 per cent c.i. -2·39 to -1·19) days; P < 0·001) compared with control groups. However, these effects vanished after excluding trials at high and unclear risk of bias. Publication bias seemed to be present for infectious complications (P = 0·002). Non-industry-funded trials reported no positive effects for overall complications (OR 1·13, 0·88 to 1·46; P = 0·34), whereas those funded by industry reported large effects (OR 0·66, 0·48 to 0·91; P = 0·01). CONCLUSION: Immunonutrition after major abdominal surgery did not seem to alter mortality (GRADE: high quality of evidence). Immunonutrition reduced overall complications, infectious complications and shortened hospital stay (GRADE: low to moderate). The existence of bias lowers confidence in the evidence (GRADE approach).

Incidence, risk factors and clinical implications of chyle leak after pancreatic surgery.

BACKGROUND: Chyle leak is a well known but poorly characterized complication after pancreatic surgery. Available data on incidence, risk factors and clinical significance of chyle leak are highly heterogeneous. METHODS: For this cohort study all patients who underwent pancreatic surgery between January 2008 and December 2012 were identified from a prospective database. Chyle leak was defined as any drainage output with triglyceride content of 110 mg/dl or more. Risk factors for chyle leak were assessed by univariable and multivariable analyses. The clinical relevance of chyle leak was evaluated using hospital stay and resolution by 14 days for short-term outcome and overall survival for long-term outcome. RESULTS: Chyle leak developed in 346 (10·4 per cent) of 3324 patients. Pre-existing diabetes, resection for malignancy, distal pancreatectomy, duration of surgery 180 min or longer, and concomitant pancreatic fistula or abscess were independent risk factors for chyle leak. Both isolated chyle leak and coincidental chyle leak (with other intra-abdominal complications) were associated with prolonged hospital stay. Some 178 (87·7 per cent) of 203 isolated chyle leaks and 90 (70·3 per cent) of 128 coincidental chyle leaks resolved with conservative management within 14 days. Initial and maximum drainage volumes were associated with duration of hospital stay and success of therapy by 14 days. Impact on survival was restricted to chyle leaks that persisted at 14 days in patients with cancer undergoing palliative surgery. CONCLUSION: Chyle leak is a relevant complication, with an incidence of more than 10 per cent after pancreatic surgery, and has a major impact on hospital stay. Drainage volume is associated with hospital stay and success of therapy.

Meta-analysis of surgical outcome after enucleation versus standard resection for pancreatic neoplasms.

BACKGROUND: Pancreatic enucleation is a tissue-sparing approach to pancreatic neoplasms and may result in better postoperative pancreatic function than standard pancreatic resection. The objective of this review was to compare the postoperative outcome after pancreatic enucleation versus standard resection. METHODS: MEDLINE, Embase and the Cochrane Library were searched systematically until February 2015 to identify studies comparing the outcome of enucleation versus standard resection for pancreatic neoplasms. After critical appraisal, meta-analysis was performed and the findings were presented as odds ratios or weighted mean differences with corresponding 95 per cent c.i. RESULTS: Twenty-two observational studies (1148 patients) were included. Duration of surgery (P < 0.001), blood loss (P < 0.001), length of hospital stay (P = 0.04), and postoperative endocrine (P < 0.001) and exocrine (P = 0.01) insufficiency were lower after enucleation than after standard resection. Mortality (P = 0.44), overall complications (P = 0.74), reoperation rate (P = 0.93) and delayed gastric emptying (P = 0.15) were not significantly different between the two approaches. The overall rate of postoperative pancreatic fistula (POPF) was higher after enucleation than after standard resection (P < 0.001). However, the raised POPF rate did not result in higher mortality or overall morbidity. Sensitivity analysis of high-volume studies (total of more than 20 enucleations and more than 4 per year) showed that, in specialized centres, enucleation can be performed with no increased risk of POPF (P = 0.12). CONCLUSION: Compared with standard resection, pancreatic enucleation can be performed effectively and with comparable safety in high-volume institutions. Enucleation should be considered instead of standard resection for selected pancreatic neoplasms.

Meta-analysis of reconstruction techniques after low anterior resection for rectal cancer.

BACKGROUND: Options for reconstruction after low anterior resection (LAR) for rectal cancer include straight or side-to-end coloanal anastomosis (CAA), colonic J pouch and transverse coloplasty. This systematic review compared these techniques in terms of function, surgical outcomes and quality of life. METHODS: A systematic literature search (MEDLINE, Embase and the Cochrane Library, from inception of the databases until November 2014) was conducted to identify randomized clinical trials comparing reconstructive techniques after LAR. Random-effects meta-analyses were carried out, and results presented as weighted odds ratios or mean differences with corresponding 95 per cent c.i. A network meta-analysis was conducted for the outcome anastomotic leakage. RESULTS: The search yielded 965 results; 21 trials comprising data from 1636 patients were included. Colonic J pouch was associated with lower stool frequency and antidiarrhoeal medication use for up to 1 year after surgery compared with straight CAA. Transverse coloplasty and side-to-end CAA had similar functional outcomes to the colonic J pouch. No superiority was found for any of the techniques in terms of anastomotic leak rate. CONCLUSION: Colonic J pouch and side-to-end CAA or transverse coloplasty lead to a better functional outcome than straight CAA for the first year after surgery.

[Benefit assessment of operative interventions from the perspective of surgical research]. / Nutzenbewertung operativer Maßnahmen aus der Perspektive der chirurgischen Forschung.

The benefit assessment of surgical procedures serves as the basis for the concept of evidence-based surgery. However, especially in the field of surgery, many interventions are lacking assessment in high-quality clinical trials. Therefore, a well-structured benefit assessment of surgical interventions in the future is imperative. Considering the different perspectives, e.g. of the patients, surgeons, industry or health care investors, the implications of the benefits and risks of a procedure can differ significantly. Researchers have to abide by different regulations, depending on the type of intervention being evaluated in a surgical trial. Furthermore, the benefit assessment of surgical procedures poses specific challenges, from the choice of a relevant endpoint to issues concerning the standardization of the interventions and the impact of learning curves. The IDEAL concept, which was established by a group of international experts in 2009, serves as a framework for the future development and assessment of innovations in the field of surgery. For example, the SDGC (Study Center of the German Society of Surgery) and CHIR-Net (Surgical Studies Network) indicate that such collaborations of clinicians and methodologists can lead to the creation of a qualified structure for the effective benefit assessment of surgical procedures. In the future, the aforementioned evidence gaps must be eliminated and innovations evaluated efficiently by the work of such networks.

[Evidence-based perioperative medicine]. / Evidenzbasierte perioperative Medizin.

Perioperative medical interventions are an integral part of modern surgical management. In addition to the main manual aspects of surgical interventions, surgeons must also be familiar with preoperative and postoperative medical interventions. This ranges from the indications for perioperative anticoagulation, handling of drainage, adjusting the perioperative analgesia, prescribing an antibiotic prophylaxis to deciding whether a preoperative bowel preparation is necessary. Therefore, this article exemplifies some areas in perioperative medicine. Based on the best available evidence, it should always be critically assessed whether these perioperative interventions really contribute to the success of the treatment.

[Tracheostomy techniques]. / Tracheotomietechniken.

Due to the comprehensive establishment of modern techniques, tracheostomy has become a routine procedure in intensive care units (ICU). The negative effects of prolonged translaryngeal intubation on the laryngeal and tracheal mucosa up to tracheal stenosis can be reduced by tracheostomy. Furthermore, long-term ventilation is facilitated; however, there is no clear evidence on the optimal timing of tracheostomy in critically ill patients. The specific indications and contraindications of surgical as well as percutaneous tracheostomy must be strictly observed for a safe and successful intervention. Exchanging the tracheostomy tube may lead to potentially dangerous situations especially after percutaneous tracheostomy. A standardized and structured approach is therefore recommended.