The effect of prophylactic mesh implantation on the development of incisional hernias in patients with elevated BMI: a systematic review and meta-analysis.

BACKGROUND: Incisional hernia is a common complication after midline laparotomy. In certain risk profiles incidences can reach up to 70%. Large RCTs showed a positive effect of prophylactic mesh reinforcement (PMR) in high-risk populations. OBJECTIVES: The aim was to evaluate the effect of prophylactic mesh reinforcement on incisional hernia reduction in obese patients after midline laparotomies. METHODS: Following the PRISMA guidelines, a systematic literature search in Medline, Web of Science and CENTRAL was conducted. RCTs investigating PMR in patients with a BMI ≥ 27 reporting incisional hernia as primary outcome were included. Study quality was assessed using the Cochrane risk-of-bias tool and certainty of evidence was rated according to the GRADE Working Group grading of evidence. A random-effects model was used for the meta-analysis. Secondary outcomes included postoperative complications. RESULTS: Out of 2298 articles found by a systematic literature search, five RCTs with 1136 patients were included. There was no significant difference in the incidence of incisional hernia when comparing PMR with primary suture (odds ratio (OR) 0.59, 95% CI 0.34-1.01, p = 0.06, GRADE: low). Meta-analyses of seroma formation (OR 1.62, 95% CI 0.72-3.65; p = 0.24, GRADE: low) and surgical site infections (OR 1.52, 95% CI 0.72-3.22, p = 0.28, GRADE: moderate) showed no significant differences as well as subgroup analyses for BMI ≥ 40 and length of stay. CONCLUSIONS: We did not observe a significant reduction of the incidence of incisional hernia with prophylactic mesh reinforcement used in patients with elevated BMI. These results stand in contrast to the current recommendation for hernia prevention in obese patients.

Mid-term quality of life after gastric band removal and single-stage conversion to gastric bypass: a single-center cohort study.

BACKGROUND: Revision surgeries in patients with failed gastric banding including band removal are increasingly necessary. However, long-term outcomes after band removal alone are unsatisfactory due to weight regain and limited improvement in quality of life. This study aimed to report mid-term quality of life outcomes after gastric band removal and single-stage conversion to Roux-en-Y gastric bypass. METHODS: Data of 108 patients who underwent conversion surgery from 2011 to 2017 were extracted from a prospective database and retrospectively analyzed. During follow-up visits, physical and laboratory data as well as quality of life questionnaires were obtained. RESULTS: Postoperative mean Moorehead score increased significantly after 1 year (1.62 ± 0.86, p < 0.001) and after 5 years (1.55 ± 0.84, p < 0.001) compared to baseline values (0.72 ± 1.1). The mean follow-up time was 53 months. Moorehead scores at 1, 2, and 5 years postoperative were available in 75% (n = 81), 71% (n = 77), and 42% (n = 45) of cases, respectively. Mixed ANOVA analysis showed a significantly superior increase in Moorehead score in males (p = 0.024). No other significant predictors were identified. Lasting BMI reduction (- 4.6 to 33.0 ± 6.7 kg/m2, p < 0.001) and weight loss (- 12.9% (- 13.6 kg), p < 0.001) 5 years after conversion surgery were seen. Postoperative complications occurred in 35% (n = 38) of patients with a re-operation rate of 30.5% (n = 33). CONCLUSION: The current study shows that band removal with single-stage gastric bypass in patients with failed gastric banding leads to a lasting improvement in quality of life and may be the rescue procedure of choice in this setting.

Learning Curves in Open, Laparoscopic, and Robotic Pancreatic Surgery: A Systematic Review and Proposal of a Standardization.

Objective: To depict and analyze learning curves for open, laparoscopic, and robotic pancreatoduodenectomy (PD) and distal pancreatectomy (DP). Background: Formal training is recommended for safe introduction of pancreatic surgery but definitions of learning curves vary and have not been standardized. Methods: A systematic search on PubMed, Web of Science, and CENTRAL databases identified studies on learning curves in pancreatic surgery. Primary outcome was the number needed to reach the learning curve as defined by the included studies. Secondary outcomes included endpoints defining learning curves, methods of analysis (statistical/arbitrary), and classification of learning phases. Results: Out of 1115 articles, 66 studies with 14,206 patients were included. Thirty-five studies (53%) based the learning curve analysis on statistical calculations. Most often used parameters to define learning curves were operative time (n = 51), blood loss (n = 17), and complications (n = 10). The number of procedures to surpass a first phase of learning curve was 30 (20-50) for open PD, 39 (11-60) for laparoscopic PD, 25 (8-100) for robotic PD (P = 0.521), 16 (3-17) for laparoscopic DP, and 15 (5-37) for robotic DP (P = 0.914). In a three-phase model, intraoperative parameters improved earlier (first to second phase: operating time -15%, blood loss -29%) whereas postoperative parameters improved later (second to third phase: complications -46%, postoperative pancreatic fistula -48%). Studies with higher sample sizes showed higher numbers of procedures needed to overcome the learning curve (rho = 0.64, P < 0.001). Conclusions: This study summarizes learning curves for open-, laparoscopic-, and robotic pancreatic surgery with different definitions, analysis methods, and confounding factors. A standardized reporting of learning curves and definition of phases (competency, proficiency, mastery) is desirable and proposed.

Meta-analysis of randomized controlled trials and individual patient data comparing minimally invasive with open oesophagectomy for cancer.

BACKGROUND: Minimally invasive oesophagectomy (MIO) for oesophageal cancer may reduce surgical complications compared with open oesophagectomy. MIO is, however, technically challenging and may impair optimal oncological resection. The aim of the present study was to assess if MIO for cancer is beneficial. METHODS: A systematic literature search in MEDLINE, Web of Science and CENTRAL was performed and randomized controlled trials (RCTs) comparing MIO with open oesophagectomy were included in a meta-analysis. Survival was analysed using individual patient data. Random-effects model was used for pooled estimates of perioperative effects. RESULTS: Among 3219 articles, six RCTs were identified including 822 patients. Three-year overall survival (56 (95 per cent c.i. 49 to 62) per cent for MIO versus 52 (95 per cent c.i. 44 to 60) per cent for open; P = 0.54) and disease-free survival (54 (95 per cent c.i. 47 to 61) per cent versus 50 (95 per cent c.i. 42 to 58) per cent; P = 0.38) were comparable. Overall complication rate was lower for MIO (odds ratio 0.33 (95 per cent c.i. 0.20 to 0.53); P < 0.010) mainly due to fewer pulmonary complications (OR 0.44 (95 per cent c.i. 0.27 to 0.72); P < 0.010), including pneumonia (OR 0.41 (95 per cent c.i. 0.22 to 0.77); P < 0.010). CONCLUSION: MIO for cancer is associated with a lower risk of postoperative complications compared with open resection. Overall and disease-free survival are comparable for the two techniques. LAY SUMMARY: Oesophagectomy for cancer is associated with a high risk of complications. A minimally invasive approach might be less traumatic, leading to fewer complications and may also improve oncological outcome. A meta-analysis of randomized controlled trials comparing minimally invasive to open oesophagectomy was performed. The analysis showed that the minimally invasive approach led to fewer postoperative complications, in particular, fewer pulmonary complications. Survival after surgery was comparable for the two techniques.

Oesophagectomy for cancer is associated with a high risk of complications. A minimally invasive approach might be less traumatic, leading to fewer complications and may also improve oncological outcome. A meta-analysis of randomized controlled trials comparing minimally invasive to open oesophagectomy was performed. The analysis showed that the minimally invasive approach led to fewer postoperative complications, in particular, fewer pulmonary complications. Survival after surgery was comparable for the two techniques.

Virtual reality simulation in robot-assisted surgery: meta-analysis of skill transfer and predictability of skill.

BACKGROUND: The value of virtual reality (VR) simulators for robot-assisted surgery (RAS) for skill assessment and training of surgeons has not been established. This systematic review and meta-analysis aimed to identify evidence on transferability of surgical skills acquired on robotic VR simulators to the operating room and the predictive value of robotic VR simulator performance for intraoperative performance. METHODS: MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science were searched systematically. Risk of bias was assessed using the Medical Education Research Study Quality Instrument and the Newcastle-Ottawa Scale for Education. Correlation coefficients were chosen as effect measure and pooled using the inverse-variance weighting approach. A random-effects model was applied to estimate the summary effect. RESULTS: A total of 14 131 potential articles were identified; there were eight studies eligible for qualitative and three for quantitative analysis. Three of four studies demonstrated transfer of surgical skills from robotic VR simulators to the operating room measured by time and technical surgical performance. Two of three studies found significant positive correlations between robotic VR simulator performance and intraoperative technical surgical performance; quantitative analysis revealed a positive combined correlation (r = 0.67, 95 per cent c.i. 0.22 to 0.88). CONCLUSION: Technical surgical skills acquired through robotic VR simulator training can be transferred to the operating room, and operating room performance seems to be predictable by robotic VR simulator performance. VR training can therefore be justified before operating on patients.

Endoscopic versus surgical treatment for infected necrotizing pancreatitis: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To compare outcomes of endoscopic and surgical treatment for infected necrotizing pancreatitis (INP) based on results of randomized controlled trials (RCT). BACKGROUND: Treatment of INP has changed in the last two decades with adoption of interventional, endoscopic and minimally invasive surgical procedures for drainage and necrosectomy. However, this relies mostly on observational studies. METHODS: We performed a systematic review following Cochrane and PRISMA guidelines and AMSTAR-2 criteria and searched CENTRAL, Medline and Web of Science. Randomized controlled trails that compared an endoscopic treatment to a surgical treatment for patients with infected walled-off necrosis and included one of the main outcomes were eligible for inclusion. The main outcomes were mortality and new onset multiple organ failure. Prospero registration ID: CRD42019126033 RESULTS: Three RCTs with 190 patients were included. Intention to treat analysis showed no difference in mortality. However, patients in the endoscopic group had statistically significant lower odds of experiencing new onset multiple organ failure (odds ratio (OR) confidence interval [CI] 0.31 [0.10, 0.98]) and were statistically less likely to suffer from perforations of visceral organs or enterocutaneous fistulae (OR [CI] 0.31 [0.10, 0.93]), and pancreatic fistulae (OR [CI] 0.09 [0.03, 0.28]). Patients with endoscopic treatment had a statistically significant lower mean hospital stay (Mean difference [CI] - 7.86 days [- 14.49, - 1.22]). No differences in bleeding requiring intervention, incisional hernia, exocrine or endocrine insufficiency or ICU stay were apparent. Overall certainty of evidence was moderate. CONCLUSION: There seem to be possible benefits of endoscopic treatment procedure. Given the heterogenous procedures in the surgical group as well as the low amount of randomized evidence, further studies are needed to evaluate the combination of different approaches and appropriate timepoints for interventions.

Meta-analysis of α-blockade versus no blockade before adrenalectomy for phaeochromocytoma.

BACKGROUND: Preoperative α-blockade in phaeochromocytoma surgery is recommended by all guidelines to prevent intraoperative cardiocirculatory events. The aim of this meta-analysis was to assess the benefit of such preoperative treatment compared with no treatment before adrenalectomy for phaeochromocytoma. METHODS: A systematic literature search was undertaken in MEDLINE, Web of Science and CENTRAL without language restrictions. Randomized and non-randomized comparative studies investigating preoperative α-blockade in phaeochromocytoma surgery were included. Data on perioperative safety, effectiveness and outcomes were extracted. Pooled results were calculated as an odds ratio or mean difference with 95 per cent confidence interval. RESULTS: A total of four retrospective comparative studies were included investigating 603 patients undergoing phaeochromocytoma surgery. Mortality, cardiovascular complications, mean maximal intraoperative systolic and diastolic BP, and mean maximal intraoperative heart rate did not differ between patients with or without α-blockade. The certainty of the evidence was very low owing to the inferior quality of studies. CONCLUSION: This meta-analysis has shown a lack of evidence for preoperative α-blockade in surgery for phaeochromocytoma. RCTs are needed to evaluate whether preoperative α-blockade can be abandoned.

ANTECEDENTES: Todas las guías recomiendan el bloqueo alfa preoperatorio en la cirugía del feocromocitoma para prevenir eventos cardiocirculatorios intraoperatorios. El objetivo de este metaanálisis fue evaluar el beneficio de dicho tratamiento preoperatorio antes de la adrenalectomía por feocromocitoma en comparación con ningún tratamiento. MÉTODOS: Se realizó una búsqueda sistemática de la literatura en MEDLINE, Web of Science y CENTRAL sin restricciones de idioma. Se incluyeron estudios comparativos aleatorizados y no aleatorizados que investigaron el bloqueo alfa preoperatorio en la cirugía del feocromocitoma. Se extrajeron los datos en relación a la seguridad perioperatoria, la efectividad y los resultados. Los resultados agrupados se mostraron como razón de oportunidades (odds ratio, OR) o diferencia de medias (MD) con el correspondiente i.c. del 95%. RESULTADOS: Se incluyeron un total de cuatro estudios comparativos retrospectivos que analizaron a 603 pacientes sometidos a cirugía del feocromocitoma. La mortalidad, las complicaciones cardiovasculares, la media del valor máximo de la presión arterial sistólica y diastólica intraoperatoria y la media del valor máximo de la frecuencia cardíaca intraoperatoria no difirieron entre pacientes con o sin bloqueo. La certeza de la evidencia fue muy baja debido a la baja calidad de los estudios. CONCLUSIÓN: Este metaanálisis demuestra la falta de evidencia del bloqueo alfa preoperatorio en la cirugía del feocromocitoma. Se necesitan ensayos controlados aleatorizados para evaluar si se puede abandonar el bloqueo alfa preoperatorio.

Learning Curves of Laparoscopic Roux-en-Y Gastric Bypass and Sleeve Gastrectomy in Bariatric Surgery: a Systematic Review and Introduction of a Standardization.

BACKGROUND: The most commonly performed bariatric procedures are laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (LSG). Impact of learning curves on operative outcome has been well shown, but the necessary learning curves have not been clearly defined. This study provides a systematic review of the literature and proposes a standardization of phases of learning curves for RYGB and LSG. METHODS: A systematic literature search was performed using PubMed, Web of Science, and CENTRAL databases. All studies specifying a number or range of approaches to characterize the learning curve for RYGB and LSG were selected. RESULTS: A total of 28 publications related to learning curves for 27,770 performed bariatric surgeries were included. Parameters used to determine the learning curve were operative time, complications, conversions, length of stay, and blood loss. Learning curve range was 30-500 (RYGB) and 30-200 operations (LSG) according to different definitions and respective phases of learning curves. Learning phases described the number of procedures necessary to achieve predefined skill levels, such as competency, proficiency, and mastery. CONCLUSIONS: Definitions of learning curves for bariatric surgery are heterogeneous. Introduction of the three skill phases competency, proficiency, and mastery is proposed to provide a standardized definition using multiple outcome variables to enable better comparison in the future. These levels are reached after 30-70, 70-150, and up to 500 RYGB, and after 30-50, 60-100, and 100-200 LSG. Training curricula, previous laparoscopic experience, and high procedure volume are hallmarks for successful outcomes during the learning curve.

Meta-analysis of recurrence pattern after resection for pancreatic cancer.

BACKGROUND: Initial recurrence mapping of resected pancreatic ductal adenocarcinoma (PDAC) could help in stratifying patient subpopulations for optimal postoperative follow-up. The aim of this systematic review and meta-analysis was to investigate the initial recurrence patterns of PDAC and to correlate them with clinicopathological factors. METHODS: MEDLINE and Web of Science databases were searched systematically for studies reporting first recurrence patterns after PDAC resection. Data were extracted from the studies selected for inclusion. Pooled odds ratios (ORs) and 95 per cent confidence intervals were calculated to determine the clinicopathological factors related to the recurrence sites. The weighted average of median overall survival was calculated. RESULTS: Eighty-nine studies with 17 313 patients undergoing PDAC resection were included. The weighted median rates of initial recurrence were 20·8 per cent for locoregional sites, 26·5 per cent for liver, 11·4 per cent for lung and 13·5 per cent for peritoneal dissemination. The weighted median overall survival times were 19·8 months for locoregional recurrence, 15·0 months for liver recurrence, 30·4 months for lung recurrence and 14·1 months for peritoneal dissemination. Meta-analysis revealed that R1 (direct) resection (OR 2·21, 95 per cent c.i. 1·12 to 4·35), perineural invasion (OR 5·19, 2·79 to 9·64) and positive peritoneal lavage cytology (OR 5·29, 3·03 to 9·25) were significantly associated with peritoneal dissemination as initial recurrence site. Low grade of tumour differentiation was significantly associated with liver recurrence (OR 4·15, 1·71 to 10·07). CONCLUSION: Risk factors for recurrence patterns after surgery could be considered for specific surveillance and treatments for patients with pancreatic cancer.

ANTECEDENTES: El mapeo del patrón de recidiva inicial tras la resección de un adenocarcinoma ductal pancreático (pancreatic ductal adenocarcinoma, PDAC) podría ayudar a estratificar subpoblaciones de pacientes para un seguimiento postoperatorio óptimo. El objetivo de esta revisión sistemática con metaanálisis fue investigar los patrones de recidiva inicial de PDAC y correlacionarlos con factores clínico-patológicos. MÉTODOS: Se realizaron búsquedas sistemáticas en las bases de datos MEDLINE y Web of Science para seleccionar estudios que presentaran información sobre los patrones de recidiva inicial después de la resección del PDAC. Se extrajeron los datos de los estudios seleccionados para su inclusión en el metaanálisis. Se calcularon las razones de oportunidades agrupadas (pooled odds ratio, OR) y los i.c. del 95% para definir los factores clínico-patológicos relacionados con las localizaciones de la recidiva. Se estimó el promedio ponderado de la mediana de la supervivencia global. RESULTADOS: Se incluyeron 89 estudios con 17.313 pacientes a los que se realizó una resección por PDAC. Las tasas medias ponderadas de las localizaciones de la recidiva inicial fueron del 20,8% para la locorregional, 26,5% para las hepáticas, 11,4% para el pulmón y 13,5% para la diseminación peritoneal. La mediana ponderada de supervivencia global fue de 19,8 meses (locorregional), 15,0 meses (hígado), 30,4 meses (pulmón) y 14,1 meses (diseminación peritoneal). El metaanálisis demostró que la resección R1 (inicial) (OR 2,21, i.c. del 95% 1,12-4,35), la invasión perineural (OR 5,19; i.c. del 95% 2,79-9,64) y la positividad de la citología del lavado peritoneal (OR 5,29; i.c. del 95% 3,03-9,25) se asociaron significativamente con la diseminación peritoneal como localización de recidiva inicial. El bajo grado de diferenciación tumoral se asoció significativamente con la recidiva hepática (OR 4,15; i.c. del 95%: 1,71-10,07). CONCLUSIÓN: Se podrían tener en cuenta estos factores de riesgo de los patrones de recidiva tras la cirugía para realizar un seguimiento y tratamiento específicos en pacientes con cáncer de páncreas.

Meta-analysis of effect of routine enteral nutrition on postoperative outcomes after pancreatoduodenectomy.

BACKGROUND: The optimal nutritional treatment after pancreatoduodenectomy is still unclear. The aim of this meta-analysis was to investigate the impact of routine enteral nutrition following pancreatoduodenectomy on postoperative outcomes. METHODS: RCTs comparing enteral nutrition (regular oral intake with routine tube feeding) with non-enteral nutrition (regular oral intake with or without parenteral nutrition) after pancreatoduodenectomy were sought systematically in the MEDLINE, Cochrane Library and Web of Science databases. Postoperative data were extracted. Random-effects meta-analyses were performed to compare postoperative outcomes in the two arms, and pooled odds ratios (ORs) or mean differences (MDs) were calculated with 95 per cent confidence intervals. In subgroup analyses, the routes of nutrition were assessed. Percutaneous tube feeding and nasojejunal tube feeding were each compared with parenteral nutrition. RESULTS: Eight RCTs with a total of 955 patients were included. Enteral nutrition was associated with a lower incidence of infectious complications (OR 0·66, 95 per cent c.i. 0·43 to 0·99; P = 0·046) and a shorter length of hospital stay (MD -2·89 (95 per cent c.i. -4·99 to -0·80) days; P < 0·001) than non-enteral nutrition. Percutaneous tube feeding had a lower incidence of infectious complications (OR 0·47, 0·25 to 0·87; P = 0·017) and a shorter hospital stay (MD -1·56 (-2·13 to -0·98) days; P < 0·001) than parenteral nutrition (3 RCTs), whereas nasojejunal tube feeding was not associated with better postoperative outcomes (2 RCTs). CONCLUSION: As a supplement to regular oral diet, routine enteral nutrition, especially via a percutaneous enteral tube, may improve postoperative outcomes after pancreatoduodenectomy.

[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.

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 the prognostic role of perioperative platelet count in posthepatectomy liver failure and mortality.

BACKGROUND: Emerging evidence suggests that the perioperative platelet count (PLT) can predict posthepatectomy liver failure (PHLF). In this systematic review and meta-analysis, the impact of perioperative PLT on PHLF and mortality was evaluated. METHODS: MEDLINE and Web of Science databases were searched systematically for relevant literature up to January 2018. All studies comparing PHLF or mortality in patients with a low versus high perioperative PLT were included. Study quality was assessed using methodological index for non-randomized studies (MINORS) criteria. Meta-analyses were performed using Mantel-Haenszel tests with a random-effects model, and presented as odds ratios (ORs) with 95 per cent confidence intervals. RESULTS: Thirteen studies containing 5260 patients were included in the meta-analysis. Two different cut-off values for PLT were used: 150 and 100/nl. Patients with a perioperative PLT below 150/nl had higher PHLF (4 studies, 817 patients; OR 4·79, 95 per cent c.i. 2·89 to 7·94) and mortality (4 studies, 3307 patients; OR 3·78, 1·48 to 9·62) rates than patients with a perioperative PLT of 150/nl or more. Similarly, patients with a PLT below 100/nl had a significantly higher risk of PHLF (4 studies, 949 patients; OR 4·65, 2·60 to 8·31) and higher mortality rates (7 studies, 3487 patients; OR 6·35, 2·99 to 13·47) than patients with a PLT of 100/nl or greater. CONCLUSION: A low perioperative PLT correlates with higher PHLF and mortality rates after hepatectomy.

Comparison of chlorhexidine-isopropanol with isopropanol skin antisepsis for prevention of surgical-site infection after abdominal surgery.

BACKGROUND: Prevention of surgical-site infection (SSI) has received increasing attention. Clinical trials have focused on the role of skin antisepsis in preventing SSI. The benefit of combining antiseptic chlorhexidine with alcohol has not been compared with alcohol-based skin preparation alone in a prospective controlled clinical trial. METHODS: Between August and October 2014, patients undergoing abdominal surgery received preoperative skin antisepsis with 70 per cent isopropanol (PA). Those treated between November 2014 and January 2015 received 2 per cent chlorhexidine with 70 per cent isopropanol (CA). The primary endpoint was SSI on postoperative day (POD) 10, which was evaluated using univariable analysis, and a multivariable logistic regression model correcting for known independent risk factors for SSI. The study protocol was published in the German Registry of Clinical Studies (DRKS00011174). RESULTS: In total, 500 patients undergoing elective midline laparotomy were included (CA 221, PA 279). The incidence of superficial and deep SSIs was significantly different on POD 10: 14 of 212 (6·6 per cent) among those treated with CA and 32 of 260 (12·3 per cent) in those who received PA (P = 0·038). In the multivariable analysis, skin antisepsis with CA was an independent factor for reduced incidence of SSI on POD 10 (P = 0·034). CONCLUSION: This study showed a benefit of adding chlorhexidine to alcohol for skin antisepsis in reducing early SSI compared with alcohol alone.

Meta-analysis of metabolic surgery versus medical treatment for microvascular complications in patients with type 2 diabetes mellitus.

BACKGROUND: This study aimed to examine the effect of metabolic surgery on pre-existing and future microvascular complications in patients with type 2 diabetes mellitus (T2DM) in comparison with medical treatment. Although metabolic surgery is the most effective treatment for obese patients with T2DM regarding glycaemic control, it is unclear whether the incidence or severity of microvascular complications is reduced. METHODS: A systematic literature search was performed in MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials (CENTRAL) with no language restrictions, looking for RCTs, case-control trials and cohort studies that assessed the effect of metabolic surgery on the incidence of microvascular diabetic complications compared with medical treatment as control. The study was registered in the International prospective register of systematic reviews (CRD42016042994). RESULTS: The literature search yielded 1559 articles. Ten studies (3 RCTs, 7 controlled clinical trials) investigating 17 532 patients were included. Metabolic surgery reduced the incidence of microvascular complications (odds ratio 0·26, 95 per cent c.i. 0·16 to 0·42; P < 0·001) compared with medical treatment. Pre-existing diabetic nephropathy was strongly improved by metabolic surgery versus medical treatment (odds ratio 15·41, 1·28 to 185·46; P = 0·03). CONCLUSION: In patients with T2DM, metabolic surgery prevented the development of microvascular complications better than medical treatment . Metabolic surgery improved pre-existing diabetic nephropathy compared with medical treatment.

Meta-analysis of delayed gastric emptying after pylorus-preserving versus pylorus-resecting pancreatoduodenectomy.

BACKGROUND: Delayed gastric emptying (DGE) is a frequent complication after pylorus-preserving pancreatoduodenectomy. Recent studies have suggested that resection of the pylorus is associated with decreased rates of DGE. However, superiority of pylorus-resecting pancreatoduodenectomy was not shown in a recent RCT. This meta-analysis summarized evidence of the effectiveness and safety of pylorus-preserving compared with pylorus-resecting pancreatoduodenectomy. METHODS: RCTs and non-randomized studies comparing outcomes of pylorus-preserving and pylorus-resecting pancreatoduodenectomy were searched systematically in MEDLINE, Web of Science and CENTRAL. Random-effects meta-analyses were performed and the results presented as weighted odds ratios (ORs) or mean differences with their corresponding 95 per cent confidence intervals. Subgroup analyses were performed to account for interstudy heterogeneity between RCTs and non-randomized studies. RESULTS: Three RCTs and eight non-randomized studies with a total of 992 patients were included. Quantitative synthesis across all studies showed superiority for pylorus-resecting pancreatoduodenectomy regarding DGE (OR 2·71, 95 per cent c.i. 1·48 to 4·96; P = 0·001) and length of hospital stay (mean difference 3·26 (95 per cent c.i. -1·04 to 5·48) days; P = 0·004). Subgroup analyses including only RCTs showed no significant statistical differences between the two procedures regarding DGE, and for all other effectiveness and safety measures. CONCLUSION: Pylorus-resecting pancreatoduodenectomy is not superior to pylorus-preserving pancreatoduodenectomy for reducing DGE or other relevant complications.

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).

Meta-analysis of hybrid natural-orifice transluminal endoscopic surgery versus laparoscopic surgery.

BACKGROUND: Hybrid natural-orifice transluminal endoscopic surgery (NOTES), combining access through a natural orifice with small-sized abdominal trocars, aims to reduce pain and enhance recovery. The objective of this systematic review and meta-analysis was to compare pain and morbidity in hybrid NOTES and standard laparoscopy. METHODS: A systematic literature search was performed to identify RCTs and non-RCTs comparing hybrid NOTES and standard laparoscopy. The main outcome was pain on postoperative day (POD) 1. Secondary outcomes were pain during the further postsurgical course, rescue analgesia, complications, and satisfaction with the cosmetic result. The results of meta-analysis in a random-effects model were presented as odds ratio (ORs) or standard mean differences (MDs) with 95 per cent confidence intervals. RESULTS: Six RCTs and 21 non-randomized trials including 2186 patients were identified. In hybrid NOTES the score on the numerical pain scale was lower on POD 1 (-0·75, 95 per cent c.i. -1·09 to -0·42; P = 0·001) and on POD 2-4 (-0·58, -0·91 to -0·26; P < 0·001) than that for standard laparoscopy. The need for rescue analgesia was reduced in hybrid NOTES (OR 0·36, 0·24 to 0·54; P < 0·001). The reduction in complications found for hybrid NOTES compared with standard laparoscopy (OR 0·52, 0·38 to 0·71; P < 0·001) was not significant when only RCTs were considered (OR 0·83, 0·43 to 1·60; P = 0·570). The score for cosmetic satisfaction was higher after NOTES (MD 1·14, 0·57 to 1·71; P < 0·001). CONCLUSION: Hybrid NOTES reduces postoperative pain and is associated with greater cosmetic satisfaction in selected patients.

Prospective trial to evaluate the prognostic value of different nutritional assessment scores in pancreatic surgery (NURIMAS Pancreas).

BACKGROUND: Preoperative nutritional status has an impact on patients' clinical outcome. For pancreatic surgery, however, it is unclear which nutritional assessment scores adequately assess malnutrition associated with postoperative outcome. METHODS: Patients scheduled for elective pancreatic surgery at the University of Heidelberg were screened for eligibility. Twelve nutritional assessment scores were calculated before operation, and patients were categorized as either at risk or not at risk for malnutrition by each score. The postoperative course was monitored prospectively by assessors blinded to the nutritional status. The primary endpoint was major complications evaluated for each score in a multivariable analysis corrected for known risk factors in pancreatic surgery. RESULTS: Overall, 279 patients were analysed. A major complication occurred in 61 patients (21·9 per cent). The proportion of malnourished patients differed greatly among the scores, from 1·1 per cent (Nutritional Risk Index) to 79·6 per cent (Nutritional Risk Classification). In the multivariable analysis, only raised amylase level in drainage fluid on postoperative day 1 (odds ratio (OR) 4·91, 95 per cent c.i. 1·10 to 21·84; P = 0·037) and age (OR 1·05, 1·02 to 1·09; P = 0·005) were significantly associated with major complications; none of the scores was associated with, or predicted, postoperative complications. CONCLUSION: None of the nutritional assessment scores defined malnutrition relevant to complications after pancreatic surgery and these scores may thus be abandoned.