Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jul 2011
Randomized Controlled Trial Comparative Study Clinical TrialLow-volume ultrasound-guided nerve block provides inferior postoperative analgesia compared to a higher-volume landmark technique.
Ultrasound guidance reduces the required local anesthetic volume for successful peripheral nerve blockade, but it is unclear whether this impacts postoperative analgesia. This prospective, randomized, observer-blinded study tested the hypothesis that a low-volume ultrasound-guided ankle block would provide similar analgesia after foot surgery compared with a conventional-volume surface landmark technique. ⋯ Low-volume ultrasound-guided ankle block is associated with a high block success rate after foot surgery; however, compared with a conventional volume (surface landmark) technique, the reduced local anesthetic volume marginally compromises postoperative analgesia during the first 24 hours.
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Reg Anesth Pain Med · Jul 2011
Case ReportsRecognition of an incidental abscess and a hematoma during ultrasound-guided femoral nerve block.
Ultrasound guidance for femoral nerve blockade allows visualization of normal and abnormal anatomy. Two cases of femoral nerve blockade under ultrasound guidance are presented where a major perineural pathologic lesion was incidentally revealed. ⋯ We review and discuss incidental pathologic lesions that can be found in the femoral region. Identification of these 2 pathologic lesions facilitated our perioperative management strategies in two separate cases.
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Reg Anesth Pain Med · Jul 2011
Comparative StudyDo diagnostic blocks have beneficial effects on pain processing?
Diagnostic blocks of cervical zygapophysial joints have been used as part of the management strategy for patients with chronic neck pain. Little information is available regarding the sensory processing changes that occur after these common procedures. In a hypothesis-generating prospective study, the pressure-pain thresholds, electrical pain thresholds, and descending inhibitory modulation response using the conditioned pain modulation paradigm are described for 9 patients with cervical zygapophysial joint pain that underwent successful comparative diagnostic blocks. ⋯ Our preliminary evidence suggests that the perturbations to the sensory processing system from effective diagnostic blocks affect the tonic inhibitory system in a positive manner. Conditioned pain modulation, however, needs to be interpreted in the context of altered pain thresholds, and future studies should aim to investigate the shift in the nociceptive balance between facilitatory and inhibitory control after therapeutic interventions.
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Reg Anesth Pain Med · Jul 2011
Comparative StudyMidazolam activates the intrinsic pathway of apoptosis independent of benzodiazepine and death receptor signaling.
Midazolam has neurotoxic properties when administered neuraxially in vivo. Furthermore, midazolam induces neurodegeneration in neonatal animal models in combination with other general anesthetics. Therefore, this study focuses on the mechanism of neurotoxicity by midazolam in neuronal and nonneuronal cells. The study aims to evaluate the apoptotic pathway and to investigate the protective effects of the benzodiazepine antagonist flumazenil and the caspase inhibitor N-(2-quinolyl)valyl-aspartyl-(2,6-difluorophenoxy)-methylketone. ⋯ Midazolam induces apoptosis via activation of the mitochondrial pathway in a concentration-dependent manner. The mechanism of midazolam toxicity switches from caspase-dependent apoptosis to necrosis with increasing concentrations. The induction of apoptosis and necrosis by midazolam is presumably unrelated to GABAA receptor pathway signaling.