Functional anatomy of the nerve and optimal placement of the needle for successful (and) safe nerve blocks Purpose of review Summarize the current thinking concerning the clinically relevant aspects of nerve anatomy and best injection sites for nerve blocks. Recent findings The widespread use of ultrasound in regional anesthesia has changed the practice of regional anesthesia and created new possibilities. Among them is the ability to identify fascial planes, and this has become the basis for a new group of blocks, the fascial plane blocks. In this kind of blocks, the target for injection is the plane itself and not a nerve in particular. transversus abdominis plane, pectoralis muscles, erector spinae plane blocks are some examples of fascial blocks. Because injecting into a fascial plane is not controversial, these blocks are not included in our discussion of optimal placement of the needle. To determine optimal needle placement, it is important to have a clear definition of what constitutes intraneural. Although, there is almost universal agreement that the violation of the epineurium defines the intraneural concept, the literature include several studies where this assessment is erroneous. Although intentional intraneural injection is still considered objectionable, some literature suggests that injecting intraneurally, especially if extrafascicular, may be benign. This evidence is limited and anecdotal. Summary It is necessary to have a better understanding of what intraneural injection is when dealing with any type of nerve blocks, be that single nerve, plexuses, or the sciatic nerve. Perineural injections provide successful anesthesia without putting the nerve integrity at risk. That practice is supported by years of experience and common sense. Currently, there is no evidence to support any kind of intraneural injections, intrafascicular or extrafascicular. Correspondence to Carlo D. Franco, MD, FASA, Stroger Hospital Cook County Department of Anesthesiology 1901 West Harrison St, Suite 5670, Chicago, IL 60612, USA. Tel: +1-312-864-3217; fax: +1-312-864-9549; e-mail: carlofra@aol.com Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Updates on pediatric regional anesthesia safety data Purpose of review The clinical practice of anesthesia continues to evolve and grow toward increasing quality and safety while improving the patient and family perioperative experience. Within the realm of pediatric anesthesia, advances in regional anesthesia techniques are important part in this aim. Recent findings The aim of this review is to provide an update on recent advances in pediatric regional anesthesia. This includes an emphasis on safety data from large datasets that previously were not available. In addition, novel blocks within pediatric regional anesthesia will be described. Summary Large data sets have given clinical providers information into the practice of regional anesthesia. It has confirmed the safety of common regional anesthetic techniques in addition to providing guidance to improving outcomes for children. Correspondence to Angelica Vargas, MD, Division of Pediatric Anesthesiology, Department of Anesthesiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, 225 E Chicago Avenue, Chicago, IL 60611, USA. Tel: +1 312 227 5170; fax: +1 312 227 9730; e-mail: avargas@luriechildrens.org Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Patient-reported outcome measures for acute and chronic pain: current knowledge and future directions Purpose of review During the past years, patient-reported outcomes (PROs) and patient-reported outcome measures (PROMs) have become of growing awareness and importance in medical research and practice. This review summarizes recent developments concerning PROs and PROMs related to pain in the acute postoperative as well as chronic settings and indicates gaps and challenges relevant for future research and clinical applications. Recent findings There are core outcome sets (COSs) of PROs and PROMs developed for specific pain conditions but patients’ perception is not sufficiently considered in the development of corresponding concepts and instruments. Summary COSs of PRO and PROMs are crucial in the field of research to enhance the comparability of results and reducing outcome reporting bias. In clinical practice PROs and PROMs are important for allocation of treatment. Concerning the development and implementation of PROs and PROMs patients’ perspective should be thoroughly considered. Relating to acute as well as chronic pain there are some attempts to create COSs of PROs and PROMs but validity and reliability for both are still missing. Correspondence to Esther Pogatzki-Zahn, Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital of Muenster, Albert-Schweitzer-Campus 1 (Building A1), 48149 Muenster, Germany. Tel: +49 0 251 8347255; fax: +49 0 251 88704; e-mail: pogatzki@anit.uni-muenster.de Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Regional anesthesia for vascular surgery: does the anesthetic choice influence outcome? Purpose of review Outcomes following surgery are of major importance to clinicians, institutions and most importantly patients. This review examines whether regional anesthesia and analgesia influence outcome after vascular surgery. Recent findings Large database analyses of contemporary practice suggest that utilizing regional anesthesia for both open and endovascular aortic aneurysm repair, lower limb revascularization and carotid endarterectomy reduces morbidity, length of stay and possibly even mortality. Results from such analyses are limited by an inherent risk of bias but are nevertheless important given the number of patients required in randomized trials to detect differences in rare outcomes. There is minimal evidence that regional anesthesia influences longer term outcomes except for arteriovenous fistula surgery where brachial plexus blocks appear to improve 3-month fistula patency. Summary Patients undergoing vascular surgery often have multiple comorbidities and it is important to be able to outline both benefits and risks of regional anesthesia techniques. Regional anesthesia in vascular surgery allows avoidance of general anesthesia and does provide short-term benefits beyond superior analgesia. Evidence of long-term benefits is lacking in most procedures. Further work is required on newer patient centered outcomes. Correspondence to Alan J.R. Macfarlane, Department of Anaesthetics, Critical Care and Pain Medicine, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, UK. Tel: +44 0 141 211 4620; e-mail: alan.macfarlane@nhs.net Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Primer on machine learning: utilization of large data set analyses to individualize pain management Purpose of review Pain researchers and clinicians increasingly encounter machine learning algorithms in both research methods and clinical practice. This review provides a summary of key machine learning principles, as well as applications to both structured and unstructured datasets. Recent findings Aside from increasing use in the analysis of electronic health record data, machine and deep learning algorithms are now key tools in the analyses of neuroimaging and facial expression recognition data used in pain research. Summary In the coming years, machine learning is likely to become a key component of evidence-based medicine, yet will require additional skills and perspectives for its successful and ethical use in research and clinical settings. Correspondence to Patrick J. Tighe, MD, MS, J. Crayton Pruitt Family Department of Biomedical Engineering (BME), University of Florida (UF), PO Box 100254, 1600 SW Archer Road, Gainesville, FL 32610-0254, USA. Tel: +1 352 273 7844; e-mail: ptighe@anest.ufl.edu Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Regional anesthesia and pain management in patients with sleep apnea: can they improve outcomes? Purpose of Review In several guidelines, regional anesthesia and analgesia have been suggested as safer alternatives for general anesthesia and systemic analgesia for their safety profile in patients suffering from obstructive sleep apnea (OSA). However, the underlying scientific basis is still evolving. The present review is intended to provide an up-to-date account on the question whether the use of regional anesthesia improves outcomes in patients with OSA. Recent Findings A number of studies found favorable effects of regional anesthesia used in patients with OSA, including reduced incidence of major perioperative complications such as the need for mechanical ventilation, reintubation and pulmonary/cardiac complications. No negative effects of regional anesthesia specific to patients with OSA were found. Regional anesthesia was most effective when used as a sole technique, but also carried benefits when added to general anesthesia. The majority of available literature focuses on orthopedic surgery and neuraxial anesthesia. Summary Regional anesthesia can be recommended as a good strategy to treat patients with OSA whenever feasible, as it reduces the incidence of potentially catastrophic perioperative complications. However, the breadth of both surgical and regional anesthetic techniques analyzed is limited; further research should focus on extending the knowledge base beyond neuraxial anesthesia and orthopedics. Correspondence to Ottokar Stundner, Department of Anesthesiology, Perioperative, Medicine and Intensive Care Medicine, Paracelsus Medical University, Muellner Hauptstrasse 48, Salzburg, Austria. Tel: +43 5 7255 55763; fax: +43 5 7255 24197; e-mail: otto.stundner@gmail.com Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Indications, contraindications, and safety aspects of procedural sedation Purpose of review There is a steadily increasing demand for procedural sedation outside the operating room, frequently performed in comorbid high-risk adult patients. This review evaluates the feasibility and advantages of sedation vs. general anesthesia for some of these new procedures. Recent findings Generally, sedation performed by experienced staff is safe. Although for some endoscopic or transcatheter interventions sedation is feasible, results of the intervention might be improved when performed under general anesthesia. For elected procedures like intra-arterial treatment after acute ischemic stroke, avoiding general anesthesia and sedation at all might be the optimal treatment. Summary Anesthesiologists are facing continuously new indications for procedural sedation in sometimes sophisticated diagnostic or therapeutic procedures. Timely availability of anesthesia staff will mainly influence who is performing sedation, anesthesia or nonanesthesia personal. While the number of absolute contraindications for sedation decreased to almost zero, relative contraindications are becoming more relevant and should be tailored to the individual procedure and patient. Correspondence to Benedikt Preckel, Department of Anesthesiology, Amsterdam University Medical Centers UMC, Location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. Tel: +31 20 5669111; e-mail: b.preckel@amsterdamumc.nl Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Essential elements of an outpatient total joint replacement programme Purpose of review To summarize the safety and feasibility of outpatient total joint arthroplasty (TJA) from the perspectives of short-term complications, long-term functional outcomes, patient satisfaction and financial impact, and to provide evidence-based guidance on how to establish an outpatient TJA programme. Recent findings TJA has been recently transitioned from an exclusively inpatient procedure for all Medicare and Medicaid patients to an outpatient surgery in properly selected total knee arthroplasty patients. This change may decrease costs while maintaining comparable rates of readmission, adverse events, positive surgical outcomes and patient satisfaction. Summary With a standardized clinical pathway, outpatient TJA can be safe and effective in a subset of patients. Essential components of a successful outpatient TJA programme include proper patient selection, preoperative patient/family education, perioperative multidisciplinary coordination and opioid-sparing analgesia, and early and effective postdischarge planning. More studies are needed to further assess and optimize this new care paradigm. Correspondence to Jinlei Li, MD, PhD, Associate Professor, Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, USA 06510. E-mail: jinlei.li@yale.edu Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Regional anesthesia for cardiac surgery Purpose of review Anesthesia for cardiac surgery has traditionally utilized high-dose opioids to blunt the sympathetic response to surgery. However, recent data suggest that opioids prolong postoperative intubation, leading to increased morbidity. Given the increased risk of opioid dependency after in-hospital exposure to opioids, coupled with an increase in morbidity, regional techniques offer an adjunct for perioperative analgesia. The aim of this review is to describe conventional and emerging regional techniques for cardiac surgery. Recent findings Well-studied techniques such as thoracic epidurals and paravertebral blocks are relatively low risk despite lack of widespread adoption. Benefits include reduced opioid exposure after paravertebral blocks and reduced risk of perioperative myocardial infarction after epidurals. To further lower the risk of epidural hematoma and pneumothorax, new regional techniques have been studied, including parasternal, pectoral, and erector spinae plane blocks. Because these are superficial compared with paravertebral and epidural blocks, they may have even lower risks of hematoma formation, whereas patients are anticoagulated on cardiopulmonary bypass. Efficacy data have been promising, although large and generalizable studies are lacking. Summary New regional techniques for cardiac surgery may be potent perioperative analgesic adjuncts, but well-designed studies are needed to quantify the effectiveness and safety of these blocks. Correspondence to Ban C. H. Tsui, MD, Department of Anesthesiology, Perioperative, and Pain Medicine, Division of Pediatric Anesthesia, Stanford University School of Medicine, Stanford, CA 94304, USA. Tel: +1 650 723 5728; e-mail: bantsui@stanford.edu Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.

Cannabis-based medicines for chronic pain management: current and future prospects Purpose of review The medicinal use of cannabis has recently become the focus of much medical, as well as political, attention. This reality of growing use but limited evidence creates unique dilemmas for the prescribing clinician. The purpose of this review is to explore current evidence and gaps in knowledge and offer some practical considerations. Recent findings There is robust preclinical data regarding the relevance of the endocannabinoid system to many pain-relevant processes. However, evidence to support cannabis-based medicines clinical use is still lacking. The best evidence to date is in managing neuropathic pain, although whether effects are clinically significant remains undetermined. However, the safety profile of cannabinoids seems favorable, especially by comparison to other medications used for pain control. Summary The endocannabinoid system is undoubtedly a new and exciting pharmaceutical target for chronic pain management, but transition from preclinical to clinical studies has so far proved difficult. Although it is reasonable to consider cannabinoids for otherwise unresponsive pain, care should be taken in frail clinical populations. As this has become a socioeconomic and political issue in which agendas often take precedence over due diligence, there is a pressing need for unbiased empirical data and high quality evidence to better inform prescribers and patients. Correspondence to Haggai Sharon, MD, PhD, Department of Anesthesiology and Critical Care Medicine, Tel Aviv Sourasky Medical Center, Institute of Pain Medicine, Weizmann 6, Tel Aviv, Israel. Tel: +97236974477; e-mail: haggaisharon@gmail.com Copyright © 2019 YEAR Wolters Kluwer Health, Inc. All rights reserved.