To correlate the anatomical variants of the circle of Willis with their effects on the hemodynamic and geometrical parameters responsible for the pathogenesis of neurological diseases. The circle of Willis and the proximal segments of the main arteries were dissected and measured on ten formalin-fixed human brains. The anatomical variants were systematized using descriptive statistics. The mathematical models for brain perfusion and wall shear stress were developed by optimally approximating resistance to flow, vascular conductance, and branching. Eighty percent of the brains presented asymmetries, especially in the posterior communicating (70%) and anterior cerebral (40%) arteries. The posterior circulation had more variations (65.21%). Nine hypoplastic vessels were found in 7 brains. Atypical origins were observed in eight specimens. According to the mathematical models, which integrated each anatomical change in the global circle of Willis anatomy, the circle of Willis' geometry could represent a risk factor for intracranial aneurysms and atherosclerosis, mostly when hypoplastic arteries are present, due to high resistance to flow and imbalanced bifurcation geometry. Accessory vessels are less associated with cerebrovascular risk. We described anatomical variants of both the anterior and posterior circulations and their specific effects on the hemodynamic balance of cerebral blood flow.

Background and Aims: The fully-covered, lumen apposing metal stents are designed for one step placement, facilitating the direct endoscopic necrosectomy into the walled-off pancreatic necrosis. However, the prediction of the number of necrosectomy sessions in these patients is not known. This study evaluated the association between the proportion of solid necrotic material inside walled-off necrosis, as assessed during the endosonography placement of a lumen apposing metal stent, and the number of necrosectomies subsequently required. Methods: Patients from three tertiary medical centers with symptomatic walled off pancreatic necrosis (pain, infection, gastric/biliary obstruction) at more than 4 weeks after onset of acute pancreatitis were retrospectively analysed. Proportion of solid necrotic debris was estimated during endosonography procedure of lumen apposing metal stents placement. Necrosectomy was performed when obstruction or inflammation occurred subsequently. Lumen apposing metal stents were removed after clearance of necrotic content. Results: In 46 patients with successful lumen apposing metal stents placement, necrosectomy was performed in 39 patients (72.78%). Performance of 3 or more necrosectomies was significantly associated with more than 50% pancreatic necrosis (p=0.032), but not with walled-off pancreatic necrosis size or location. Necrotic infection during lumen apposing metal stents stenting was associated with hypoalbuminemia, but not with necrosectomy requirement. Clinical success after a median follow-up of 13.37 months was 87%. Conclusions: Walled-off pancreatic necrosis with more than 50% solid necrotic content were associated with more necrosectomy procedures, requiering longer endoscopy time, intravenous sedations, and higher costs.

Pain control after a laparoscopic cholecystectomy can represent a challenge, considering the side effects due to standard analgesia methods. Recently the transversus abdominis plane block (TAP Block) has been used as a part of multimodal analgesia with promising results. The subcostal approach (OSTAP Block), a variant on the TAP block, produces reliable unilateral supraumbilical analgesia. This study evaluated the efficacy of the OSTAP block with bupivacaine in laparoscopic cholecystectomy compared with the placebo OSTAP block. Sixty ASA I/II adult patients listed for elective laparoscopic cholecystectomy were randomly allocated in one of two groups: Group A (OSTAP placebo) received preoperatively bilateral OSTAP block with sterile normal saline and Group B (OSTAP bupivacaine) received bilateral preoperatively OSTAP block with the same volumes of 0.25% bupivacaine. Twenty-four hours postoperative opioid consumption, the dose of opioid required during surgery, opioid dose in the recovery unit (PACU) and PACU length of stay were evaluated. The quality of analgesia was assessed by the Visual Analogue Scale (VAS) at specific interval hours during 24 h, at rest and with movement. The mean intraoperative opioid consumption showed a significant difference between the two groups, (385 ± 72.52 mg in group A vs 173.67 ± 48.60 mg in group B, p < 0.001). The mean 24 h opioid consumption showed a statistically significant difference between groups (32 ± 26.05 mg vs 79 ± 16.68 mg, p < 0.001). PACU length of stay was significantly lower for group B patients compared with group A patients (20.67 ± 11.27 min vs 41.67 ± 12.41 min, p < 0.001). The OSTAP bupivacaine group had a statistically significant lower pain score than the OSTAP placebo group at 0, 2, 4, 6, 12, 24 h, both at rest and with movement. No signs or symptoms of local anaesthetic systemic toxicity or other complications were detected. OSTAP block with bupivacaine 0.25% can provide effective analgesia up to 24 hours after laparoscopic cholecystectomy when combined with conventional multimodal analgesia regimen.

The evaluation of patients with early hepatocellular carcinoma (HCC) referred for liver resection is still a matter of debate. Aims: 1) to compare liver stiffness measurement (LSM) by transient elastography with hepatic venous pressure gradient (HVPG) in the prediction of decompensation after liver resection in patients with cirrhosis and early HCC; 2) to identify which definition for posthepatectomy liver failure is better associated with survival.Material and methods: Fifty-one patients (MELD score of 10±3) were included. In this group, 34 patients underwent HVPG measurement, of which 13 (38%) had clinically significant portal hypertension (CSPH) and 35 patients underwent LSM (21.8±17.9 kPa). The study’s end-points were: posthepatectomy liver failure (PHLF) defined according to International Study Group of Liver Surgery criteria and 3-month decompensation defined as de novo ascites, variceal bleeding, jaundice, hepatic encephalopathy and acute kidney injury. The performance of LSM compared to HVPG in predicting the end-points were assessed by AUROC curves and accuracy.Results: Twenty (39%) patients developed PHLF and 15 (29%) developed decompensationat 3 months. Three-month decompensation tended to be better correlated with survival. LSM performed well in predicting decompensation at 3 months (AUROC=0.78, 95%CI: 0.63-0.94; p=0.01), comparable with HVPG (AUROC=0.89, 95%CI: 0.79-1.00; p<0.01) (DeLong test p=0.21). LSM was not sufficiently accurate to predict PHLF.Conclusion: LSM has a similar performance to HVPG in predicting decompensation at 3 months in patients with early HCC submitted to liver resection. Three-month decompensation is better associated with survival.

Aim: Percutaneous radiofrequency (RFA) and microwave ablation (MWA) are currently the best treatment options forpatients with liver metastases (LM) who cannot undergo a liver resection procedure. Presently, few studies have evaluated theefficacy of tumor ablation in beginner’s hands but none at all in hepatic metastasis. Our aim was to report the initial experiencewith ultrasound as a tool to guide tumor ablation in a low volume center with no experience in tumor ablation.Material and methods: We conducted a retrospective cohort study, on a series of 61 patients who had undergone percutaneous US-guided ablations for 82 LM between 2010 and 2015. Long term outcome predictors were assessed using univariate and multivariate analysis.Results: Complete ablation was achieved in 86.9% of cases (53/61). All MWA sessions (20/20) attained ablation margins >5mm, compared to 79% (49/62) for RFA sessions (p=0.031). Ablation time was significantly shorter for MWA, with a median duration of 10 minutes (range: 6-12) vs. 14 minutes (range: 10-19.5, p=0.003). There was no statistically significant difference in local tumor progression (LTP)-free survival rates between MWA and RFA (p=0.154). On univariate analysis, significant predictors for local recurrence were multiple metastases (p=0.013) and ablation margins <5 mm (p<.001), both retaining significance on multivariate analysis. Significant predictors for distant recurrence on both univariate and multivariate analysis were multiple metastases (p<0.001) and non-colorectal cancer metastases (p<0.05).Conclusion: A larger than 5 mm ablation size is critical for local tumor control. We favor the use of MWA due to its ability to achieve ablation in significantlyshorter times with less incomplete ablations.

Sorafenib is a multikinase inhibitor that has received increasing attention due to its high efficacy in hepatocellular carcinoma treatment. However, its poor pharmacokinetic properties (limited water solubility, rapid elimination, and metabolism) still represent major bottlenecks that need to be overcome in order to improve Sorafenib’s clinical application. In this paper, we propose a nanotechnology-based hybrid formulation that has the potential to overcome these challenges: sorafenib-loaded nanoliposomes. Sorafenib molecules have been incorporated into the hydrophobic lipidic bilayer during the synthesis process of nanoliposomes using an original procedure developed in our laboratory and, to the best of our knowledge, this is the first paper reporting this type of analysis. The liposomal hybrid formulations have been characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), and nanoparticle tracking analysis (NTA) that provided useful information concerning their shape, size, zeta-potential, and concentration. The therapeutic efficacy of the nanohybrids has been evaluated on a normal cell line (LX2) and two hepatocarcinoma cell lines, SK-HEP-1 and HepG2, respectively.