Articles: nerve-block.
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Anesthesia and analgesia · Nov 2000
Case ReportsThe successful use of regional anesthesia to prevent involuntary movements in a patient undergoing awake craniotomy.
The authors demonstrate that the combination of single and continuous peripheral nerve blocks allows the control of involuntary movements in patients undergoing awake craniotomy.
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Clinical Trial
Potential of a new laser target system for percutaneous CT-guided nerve blocks: technical note.
A prototype of a laser target device was used for CT-guided nerve blocks in a preliminary series of nine interventions. The system provides guidance from any possible approach. High accuracy of needle insertion was achieved; the average deviation of the planned from the actual angle was 1.4 degrees. The target device is valuable for facilitating minimally invasive therapy and can decrease the time required for the procedure.
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Anesthesia and analgesia · Nov 2000
Characteristics of ropivacaine block of Na+ channels in rat dorsal root ganglion neurons.
When used for epidural anesthesia, ropivacaine can produce a satisfactory sensory block with a minor motor block. We investigated its effect on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na(+) currents in rat dorsal root ganglion (DRG) neurons to elucidate the mechanisms underlying the above effects. Whole-cell patch-clamp recordings were made from enzymatically dissociated neurons from rat DRG. A TTX-S Na(+) current was recorded preferentially from large DRG neurons and a TTX-R Na(+) current preferentially from small ones. Ropivacaine shifted the activation curve for the TTX-R Na(+) channel in the depolarizing direction and the inactivation curve for both types of Na(+) channel in the hyperpolarizing direction. Ropivacaine blocked TTX-S and TTX-R Na(+) currents, but its half-maximum inhibitory concentration (IC(50)) was significantly lower for the latter current (116 +/- 35 vs 54 +/- 14 microM; P: < 0.01); similar IC(50) values were obtained with the (R)-isomer of ropivacaine. Ropivacaine produced a use-dependent block of both types of Na(+) channels. Ropivacaine preferentially blocks TTX-R Na(+) channels over TTX-S Na(+) channels. We conclude that because TTX-R Na(+) channels exist mainly in small DRG neurons (which are responsible for nociceptive sensation), such selective action of ropivacaine could underlie the differential block observed during epidural anesthesia with this drug. ⋯ Whole-cell patch-clamp recordings of tetrodotoxin-sensitive and tetrodotoxin-resistant Na(+) currents in rat dorsal root ganglion neurons showed ropivacaine preferentially blocked tetrodotoxin-resistant Na(+) channels over tetrodotoxin-sensitive Na(+) channels. This could provide a desirable differential sensory blockade during epidural anesthesia using ropivacaine.