Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2012
Reliability of static and dynamic quantitative sensory testing in patients with painful chronic pancreatitis.
Quantitative sensory testing (QST) has proven to be an important instrument to characterize mechanisms underlying somatic and neuropathic pain disorders. However, its reliability has not previously been established in patients with visceral pain. We investigated the test-retest reliability of static and dynamic QST in patients with visceral pain due to chronic pancreatitis. ⋯ Sensory thresholds in the pancreatic viscerotomes and control areas were reproducible over time. In contrast, dynamic QST measurements reflecting active central modulation of pain processing state (ie, conditioned pain modulation) were not stable over time and showed considerable variability. These factors should be taken into consideration in case QST is used to follow disease mechanisms, drug effects, or effects of pain intervention.
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Reg Anesth Pain Med · Sep 2012
Perioperative nerve injury after total shoulder arthroplasty: assessment of risk after regional anesthesia.
One of the most debilitating complications after total shoulder arthroplasty (TSA) is perioperative nerve injury (PNI). Interscalene blockade (ISB) improves clinical outcomes after TSA, but it may increase the risk for PNI. The objective of this large-scale, single-institution cohort study was to test the hypothesis that the use of ISB increases the risk for PNI after elective TSA. ⋯ The incidence of PNI (2.2%) is consistent with previous estimates in patients undergoing TSA. The use of ISB did not increase the risk for PNI. Most patients with PNI had improvement of their neurologic symptoms. These results further support the use of ISB analgesia for patients undergoing TSA.
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Reg Anesth Pain Med · Sep 2012
Brachial plexus root injection in a human cadaver model: injectate distribution and effects on the neuraxis.
The potential for injection into the brachial plexus root at cervical levels must be considered during interscalene block or chronic pain interventions in the neck, but this phenomenon has not been well studied. In this investigation, we performed injections into the brachial plexus roots of unembalmed cadavers, with real-time ultrasound guidance, to evaluate the proximal and distal spread of the injected fluids, the potential of the injectate to reach the neuraxis, and whether the injectate could migrate into the actual substance of the spinal cord itself. ⋯ Injection directly into the neural tissue of a brachial plexus root in a cadaver model produced high pressures suggestive of intrafascicular injection and widespread flow of the injectate through the distal brachial plexus. However, proximal movement of the dye-containing injectate was more restricted, with only 1 of the injections leading to epidural spread and no apparent effects on the spinal cord.
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Reg Anesth Pain Med · Sep 2012
Duration and local toxicity of sciatic nerve blockade with coinjected site 1 sodium-channel blockers and quaternary lidocaine derivatives.
Quaternary lidocaine derivatives (QLDs) have recently received much attention because of their potential application in prolonged or sensory-selective local anesthesia. However, associated tissue toxicity is an impeding factor that makes QLDs unfavorable for clinical use. Based on the proposed intracellular site of action, we hypothesized that nerve blocks obtained from lower concentrations of QLDs would be enhanced by the coapplication of extracellularly acting site 1 sodium-channel blocker, resulting in prolonged block duration but with minimal tissue toxicity. ⋯ Coadministration of site 1 sodium-channel blockers and QLDs greatly prolongs the duration of peripheral nerve block without enhancing local tissue injury, but minimal myotoxicity still persists. It is not clear that the risks of QLDs are outweighed by the benefits in providing prolonged nerve blockade.