Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2011
Comparative StudyHigh-resolution ultrasound accurately identifies the medial antebrachial cutaneous nerve at the midarm level: a clinical anatomic study.
The present prospective volunteer study was designed to describe a technique for ultrasound identification of the medial antebrachial cutaneous nerve (MACN) and a technique for ultrasound-guided blockade of this sensory nerve of the upper limb. ⋯ The results of this investigation enable selective blockade of the MACN via ultrasound. Moreover, our data provide insight regarding the specific anatomic course and the integrity of this sensory nerve, which could be used for plastic and reconstructive surgical indications and for diagnosis of nerve injury.
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Reg Anesth Pain Med · Sep 2011
Randomized Controlled Trial Comparative StudyValue of single-injection or continuous sciatic nerve block in addition to a continuous femoral nerve block in patients undergoing total knee arthroplasty: a prospective, randomized, controlled trial.
Continuous femoral nerve block in patients undergoing total knee arthroplasty (TKA) improves and shortens postoperative rehabilitation. The primary aim of this study was to investigate whether the addition of sciatic nerve block to continuous femoral nerve block will shorten the time-to-discharge readiness. ⋯ A single-injection or continuous sciatic nerve block in addition to a femoral nerve block did not influence time-to-discharge readiness. A single-injection sciatic nerve block can reduce severe pain on the day of the surgery, whereas a continuous sciatic nerve block reduces moderate pain during mobilization on the first 2 postoperative days.
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Reg Anesth Pain Med · Sep 2011
Comparative StudyMinimum effective volume of lidocaine for ultrasound-guided supraclavicular block.
The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 μg/mL in 90% of patients (MEV90) for double-injection ultrasound-guided supraclavicular block (SCB). ⋯ For double-injection ultrasound-guided SCB, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 32 mL. Further dose finding studies are required for other concentrations of lidocaine, other local anesthetic agents and single-injection techniques.
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Reg Anesth Pain Med · Sep 2011
Comparative StudyLocal anesthetic Schwann cell toxicity is time and concentration dependent.
Peripheral nerve blocks with local anesthetics (LAs) are commonly performed to provide surgical anesthesia or postoperative analgesia. Nerve injury resulting in persistent numbness or weakness is a potentially serious complication. Local anesthetics have previously been shown to damage neuronal and Schwann cells via several mechanisms. We sought to test the hypothesis that LAs are toxic to Schwann cells and that the degree of toxicity is directly related to the concentration of LA and duration of exposure. Intraneural injection of LAs has been shown to produce nerve injury. We sought to test the hypothesis that a prolonged extraneural infusion of LA can also produce injury. ⋯ Local anesthetics induce Schwann cell death in a time- and concentration-dependent manner. Bupivacaine and ropivacaine have greater toxicity at intermediate concentrations, and prolonged exposure to bupivacaine produces significant toxicity even at low concentrations. Brief exposure to high concentrations of bupivacaine damages Schwann cells. Prolonged extraneural infusion of bupivacaine results in nerve injury.