Robotic Surgery in Achalasia: State of the Art.

Introduction: Achalasia is a rare primary esophageal disorder characterized by impaired functioning of the lower esophageal sphincter. The goal of treatment is to reduce symptoms and improve the quality of life. The gold standard of surgical approach is Heller-Dor myotomy. The aim of this review is to describe the use of robotic surgery in patients with achalasia. Methods: The literature review was performed by searching on PubMed, Web of Science, Scopus and EMBASE for all studies on robotic surgery for achalasia, published from January 1, 2001, to December 31, 2022. We focused our attention on randomized controlled trials (RCTs), metaanalysis, systematic reviews, and observational studies on large cohorts of patients. Furthermore, we have identified relevant articles from the reference list. Conclusions: Taking into consideration our review and experience, RHM with partial fundoplication is safe, efficient, comfortable for the surgeon and characterized by a reduction of the intraoperative perforation rate of the esophageal mucosa. This approach may represent the future for the surgical treatment of achalasia especially with a reduction in costs.

Co-movements, option pricing and risk management: an application to WTI versus Brent spread options.

Co-moments of asset returns play a major role in financial contagion during crises. We study the properties of a particular specification of the generalized bivariate normal distribution which allows for co-volatility and co-skewness. With this probability distribution, formulae for single-name and exchange options can be evaluated quickly since they are based on one-dimensional integrals. We provide a very precise approximation formula for spread option prices and derive the corresponding greeks. We perform a day-to-day re-estimation of the probability distribution on a dataset of WTI vs Brent spread options, showing the ability of this specification to capture the salient empirical features observed in the market. Finally, we show the impact of co-movements on portfolio risk management.