Techniques in regional anesthesia & pain management最新文献

Severe postoperative pain and wound hyperalgesia, a clinical sign of central sensitization, are risk factors for the development of chronic postsurgical pain. This article describes the neuronal changes that surgical pain and possibly high opioid doses cause in the central nervous system. It also relates how regional anesthesia might oppose these changes and block both the pain sensitization and the pain chronification following surgery.

The number of procedures carried out with regional anesthesia techniques is increasingly higher; this applies not only to the anesthetic act itself but also includes postoperative analgesia, with the added advantage of the possibility of being a tool that prevents pain from becoming chronic. Anesthesiologists should be adequately trained in neurostimulation and ultrasound regional anesthesia techniques. The progress of ultrasound over the last few years has pushed both anatomical cutaneous references and basic pharmacologic knowledge into the background, so as to focus essentially on ultrasound visualization. This article reviews the different elements required for a good training in regional anesthesia (phantoms, simulators, tutorials, corpse workshop, etc) without disregarding neurostimulation, and it focuses on ultrasound as the main nerve location tool for the performance of regional anesthesia techniques.

According to systematic reviews performed on adults, ultrasound provides moderate advantages in latency time reduction and block quality. Whether it really reduces the number of complications at the expense of less vascular puncturing, less diaphragm paralysis, and less pleural puncturing, together with lower doses of local anesthetic used, is a controversial question. Neither is there evidence that ultrasound achieves a higher rate of success than traditional techniques. Pediatric patients have special characteristics that differentiate them from adult patients, so the existing studies and their results should not be extrapolated. Ultrasound has a series of advantages: real-time visualization of our target or infiltration of anatomical plane; a view of the needle performing the puncture; and continuous monitoring of spreading of the local anesthetic. Few techniques satisfy so many requirements for adoption by the medical practice, but trials proving that this is an essential technique for pediatric regional anesthesia are scarce. However, ultrasound has shown to be at least as efficient and as safe as traditional techniques and should therefore be routinely used in pediatric regional anesthesia.

The use of peripheral nerve block techniques has significantly increased over the last two decades; as a consequence, development of complications has also increased. Neurostimulation has been the technique of choice for locoregional anesthesia for many years and has even been considered the gold standard. Compared with location by means of paresthesia, this technique reduces the potential risk of postoperative neuropathy, as it limits any direct contact between the needle and the nerve structure. Neurostimulation provides high efficacy with a minimum complication rate; currently, however, as ultrasound provides real time visualization of the nerve, needle and local anesthetic distribution relationship, the use of neurostimulation is less prevalent. Additionally to an apparent improvement of ultrasound-guided peripheral block success rate, there are also many trials available promoting the decrease of neurologic complications. Thus the unavoidable question comes up: is ultrasound the quality gold standard for locoregional anesthesia today? Should we rule out formerly used techniques? The current evidence for maintaining routine and exclusive use of ultrasound over any other peripheral nerve block method is limited. So, why not use all anesthetic techniques available to us, that is neurostimulation, injection pressure control, and ultrasound, to bring the complication rate down?

Chronic pain is a complex syndrome estimated to affect over 100 million Americans. Pharmaceutical-based therapy, including the use of opioids, is widely accepted as a primary treatment strategy but is associated with addiction, overdose, and diversion risk. Spinal cord stimulation (SCS) is a well-established, device-based alternative for pain management. Though effective in treating leg pain, traditional SCS has been much less effective at achieving long-term back-pain relief. In addition, stimulation with traditional SCS often leads to tingling sensations and inadvertent postural-related shocks that many patients find unpleasant. A newly developed SCS system (Nevro Corp., Menlo Park, CA) shows promise in addressing these limitations. This new device is similar to traditional SCS systems but is able to stimulate at much higher frequencies, up to 10 kHz. Prospective clinical studies of high-frequency SCS (HF-SCS) suggest improved effectiveness in treating chronic low-back pain and other types of pain that often do not respond well to traditional SCS. In addition, HF-SCS appears capable of delivering pain relief without paresthesia, both simplifying the implant procedure and improving patient satisfaction. The system is currently undergoing study in a multicenter, randomized controlled clinical trial in the United States. If the results are positive, HF-SCS could represent an important advancement in the treatment of chronic pain.

Spinal cord stimulation (SCS) is widely used for relief of chronic back and limb pain. However, numerous adverse events pose a hindrance to the widened acceptability of the treatment. A prospective, nonrandomized cohort study was conducted to compare the efficacy of a wirelessly powered SCS novel system with commercial SCS systems. Each of 12 patients were serially implanted with a Medtronic 1 × 8 SCS trial lead and a Stimwave Freedom trial lead for a 1-day evaluation. Patients were asked to report on pain relief, paresthesia coverage, paresthesia intensity, and paresthesia comfort. Ten of the 12 patients successfully underwent the trial whereas the remaining 2 procedures were terminated because of operating-equipment failures. Of the successful patients, all reported good pain relief and paresthesia for each device. The average pain reduction was reported as 80% for the Stimwave system and 66% for the Medtronic system. The average paresthesia coverage was 91% and 77%, respectfully. Differences in the averages reported by patients can be attributed to the fact that no randomization was designed in the study. The study showed that wirelessly powered, injectable SCS systems are just as effective as commercial products at relieving pain and at creating paresthesia coverage for patients who suffer from chronic back and limb pain and have the added advantages of shortened procedure time and elimination of open ports during the trial periods, as well as elimination of the need for tunneling and pocket creation for implantable pulse generators.