Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jul 2011
Comparative StudyOptical detection of the brachial plexus for peripheral nerve blocks: an in vivo swine study.
Accurate identification of nerves is critical to ensure safe and effective delivery of regional anesthesia during peripheral nerve blocks. Nerve stimulation is commonly used, but it is not perfect. Even when nerve stimulation is performed in conjunction with ultrasound guidance, determining when the needle tip is at the nerve target region can be challenging. In this in vivo pilot study, we investigated whether close proximity to the brachial plexus and penetration of the axillary artery can be identified with optical reflectance spectroscopy, using a custom needle stylet with integrated optical fibers. ⋯ Spectroscopic information obtained with the optical needle is distinct from nerve stimulation and complementary to ultrasound imaging, and it could potentially allow for reliable identification of the injection site during peripheral nerve blocks.
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Perioperative nerve injuries are devastating complications that are commonly attributed to a variety of patient, surgical, or anesthetic factors. Well-documented causes of postsurgical neuropathy include nerve compression, stretch, contusion, or transection, which can occur following surgical trauma or patient positioning. Potential anesthetic causes of perioperative nerve injury include mechanical trauma, local anesthetic toxicity, and ischemic injury. We present a case of a diffuse, bilateral neurologic deficit of unclear etiology in a patient who underwent a combined neuraxial-general anesthetic for bilateral total hip arthroplasty. ⋯ Perioperative nerve deficits not readily explained by direct surgical or anesthesia-related causes should prompt early neurologic consultation to seek alternative etiologies such as postsurgical inflammatory neuropathy. Although this condition is poorly understood, it is believed to be an idiopathic immune-mediated response to a physiologic stress (eg, surgery, regional block) and is treated with prolonged, high-dose corticosteroids. Because suppression of the immune system with high-dose steroids may result in improved neurologic outcome, it is essential that surgeons and anesthesiologists are aware of this condition so that treatment is not delayed.
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Suprascapular nerve blockade (SSNB) is a simple and safe technique for providing relief from various types of shoulder pain, including rheumatologic disorders, cancer, and trauma pain, and postoperative pain due to shoulder arthroscopy. Posterior, superior, and anterior approaches may be used, the most common being the posterior. ⋯ The different techniques of SSNB and indications for SSNB will be discussed. The complications of SSNB and outcomes of SSNB on the management of acute and chronic shoulder pain will be reviewed.
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Reg Anesth Pain Med · Jul 2011
Comparative StudyEchotexture and correlated histologic analysis of peripheral nerves important in regional anesthesia.
Peripheral nerves in different body locations display different echotextures on ultrasound imaging, and knowledge of peripheral nerve echotexture is helpful for locating target nerves. However, the degree of echogenicity is often difficult to characterize. We aimed to define objectively the degree of echogenicity of peripheral nerves using grayscale measurements and compare nerve echotexture with matched histologic samples. ⋯ This study suggests that grayscales can be used to objectively determine echogenicity and shows that grayscale measurements match well with subjective visual grading. Histologic analysis showed that both ratio of total fascicular area to whole nerve area and fascicular pattern are important determinants of echogenicity.