Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 2013
Systematic ultrasound identification of the dorsal scapular and long thoracic nerves during interscalene block.
The use of ultrasound for in-plane interscalene block shifts needle insertion to a more posterior approach through the middle scalene muscle, when compared with classic nerve stimulator techniques. Branches from the brachial plexus, including the dorsal scapular and long thoracic nerves, are often anatomically located within the middle scalene muscle. The aim of this study was to use ultrasound to identify and characterize the frequency and position of the dorsal scapular and long thoracic nerves located in the middle scalene muscle. ⋯ This descriptive study revealed that the dorsal scapular and long thoracic nerves routinely could be identified with ultrasound.
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Reg Anesth Pain Med · Jan 2013
The utility of ultrasound imaging in predicting ease of performance of spinal anesthesia in an orthopedic patient population.
Ultrasonography of the spine improves technical performance of spinal anesthesia, but what is unclear is whether it can predict difficulty. We tested the hypothesis that a good ultrasound view at a given intervertebral level is associated with absence of technical difficulty. ⋯ Ultrasound can be useful in predicting the absence of technical difficulty in performing dural puncture and thus in selecting the optimal intervertebral level for spinal anesthesia.
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Reg Anesth Pain Med · Jan 2013
The κ-opioid receptor agonist U-50488 blocks Ca2+ channels in a voltage- and G protein-independent manner in sensory neurons.
κ-Opioid receptor (κ-OR) activation is known to play a role in analgesia and central sedation. The purpose of the present study was to examine the effect of the κ-OR agonist, U-50488 (an arylacetamide), on Ca channel currents and the signaling proteins involved in acutely isolated rat dorsal root ganglion (DRG) neurons expressing the putative promoter region of the tetrodotoxin-resistant Na channel (NaV 1.8) that is known to be involved in pain transmission. ⋯ These results suggest that the antinociceptive actions mediated by U-50488 are likely due to both a direct block of Ca channels in sensory neurons as well as G protein modulation of Ca currents via κ-OR-expressing neurons.
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Reg Anesth Pain Med · Jan 2013
Bilateral loss of neural function after interscalene plexus blockade may be caused by epidural spread of local anesthetics: a cadaveric study.
Interscalene brachial plexus blockade is widely used in surgical procedures of the upper limb. Recently, we experienced the complication of a contralateral blockade after ultrasound-guided interscalene block. The clinical appearance was a blockade of both the ipsilateral and the contralateral cervical segments 6 to 8. We hypothesized that epidural spread of local anesthetics could be cause for this phenomenon. ⋯ Contralateral blockade after ultrasound-guided interscalene injection of local anesthetics is very likely to be the effect of epidural spread. Future in vivo studies are needed to understand the implications of needle location and volume on epidural spread in interscalene blockade.