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.

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.

Creation and establishment of a respiratory liver motion simulator for liver interventions.

Image-guided surgery and navigation have resulted from convergent developments in radiology, teletransmission, and computer science and are well-established procedures in the surgical routine in orthopedic, neurosurgery, and head-and-neck surgery. In abdominal surgery, however, these tools have gained little attraction so far. The inability to transfer the methodology from orthopedic or neurosurgery is mainly a result of intraoperative organ movement and shifting. To practice and establish navigated interventions in the liver, a custom-designed respiratory liver motion simulator was built which models the human torso and is easy to recreate. To simulate breathing motion, an explanted porcine or human liver is mounted to the diaphragm model of the simulator, and a lung ventilator causes a periodic movement of the liver along the craniocaudal axis. Additionally, the liver can be connected to a circulating pump device which simulates hepatic perfusion and provides real surgical options to establish navigated interventions and simulate management of possible complications. Respiratory motion caused by the simulator was evaluated with an optical tracking system and it was shown that in vitro movement and deformation of a liver mounted to the device are similar to the liver movements in human or porcine bodies. Based on the tests, it is concluded that the novel respiratory liver motion simulator is suitable for in vitro evaluation of navigated systems and interventional and surgical procedures.

[Prevention of postoperative infections : Evidence-based principles]. / Vermeidung postoperativer Infektionen : Evidenzbasierte Prinzipien.

BACKGROUND: Surgical site infections (SSI) are one of the most frequent postoperative complications worldwide and preventive measures are still an important research topic. High infection rates are not uncommon, especially in visceral surgery. At the same time, frequently not all evidence-based measures are carried out in a standardized manner. The aim of this article is to summarize the relevant literature on evidence-based measures for prevention of SSI. Although evidence-based medicine has already become well-established in surgery, the opinion of experts often still prevails. MATERIAL AND METHODS: The current literature on preventive measures and recommendations was reviewed and the results are appraised. RESULTS: Many different preventive measures could be identified in the literature, which can be classified into preoperative, intraoperative and postoperative measures. Recommendations for implementation of individual measures are made depending on the underlying evidence. CONCLUSION: The occurrence of SSI can effectively be reduced by adhering to evidence-based principles.

[Current standards of abdominal wall closure techniques : Conventional suture techniques]. / Aktuelle Studienlage zum Bauchdeckenverschluss : Klassische Nahttechniken.

BACKGROUND: The most frequent complications following midline abdominal laparotomy include incisional hernias, which develop in 10-15 % of patients and surgical site infections in 15-25 % of cases; however, the risk of these complications can be reduced by the surgical technique and the use of special suture materials. In 2010, the INLINE meta-analysis performed by the Study Centre of the German Society of Surgery (SDGC) revealed that a continuous suture technique using slowly absorbable suture material resulted in the lowest risk of developing postoperative incisional hernia after elective midline laparotomy. OBJECTIVE: The aim of this study was to perform a systematic literature search to identify all randomized controlled trials (RCTs) that have been published since 2010 concerning conventional abdominal wall closure in order to update the 2010 INLINE meta-analysis and summarize current evidence. MATERIAL AND METHODS: On 28 January 2016, a systematic literature search was performed in MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL). All RCTs dealing with abdominal wall closure after midline laparotomy were identified and included for further analysis. RESULTS: Since 2010 a total of 9 RCTs comparing different techniques of abdominal wall closure have been published. Three monocentric RCTs comparing different suture materials, showed no significant differences to the INLINE meta-analysis regarding incisional hernia development; therefore, slowly absorbable sutures using a continuous suture technique are still recommended for abdominal wall closure in elective cases. Furthermore, six RCTs were identified which investigated antimicrobial suture materials but failed to show an overall advantage for Triclosan-coated suture material with respect to surgical site infections. CONCLUSION: Current evidence shows that slowly absorbable monofilament suture material using a continuous suture technique provides the best results with regard to incisional hernia rates after elective midline laparotomy. Triclosan-coated sutures cannot be recommended as a standard suture material as they failed to reduce surgical site infections. For emergency laparotomies no evidence exists to recommend a specific kind of suture technique or a special suture material.

Precision targeting of liver lesions with a needle-based soft tissue navigation system.

In this study, we assessed the targeting precision of a previously reported needle-based soft tissue navigation system. For this purpose, we implanted 10 2-ml agar nodules into three pig livers as tumor models, and two of the authors used the navigation system to target the center of gravity of each nodule. In order to obtain a realistic setting, we mounted the livers onto a respiratory liver motion simulator that models the human body. For each targeting procedure, we simulated the liver biopsy workflow, consisting of four steps: preparation, trajectory planning, registration, and navigation. The lesions were successfully hit in all 20 trials. The final distance between the applicator tip and the center of gravity of the lesion was determined from control computed tomography (CT) scans and was 3.5 +/- 1.1 mm on average. Robust targeting precision of this order of magnitude would significantly improve the clinical treatment standard for various CT-guided minimally invasive interventions in the liver.