Regional anesthesia and pain medicine
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Reg Anesth Pain Med · May 2010
ReviewDuloxetine: a review of its pharmacology and use in chronic pain management.
Duloxetine is a serotonin and norepinephrine reuptake inhibitor that possesses antidepressant and pain-relieving properties. Compared with other antidepressants, it has a high affinity for both norepinephrine and serotonin reuptake transporters, which are relatively balanced. Analgesic onset has been observed within the first week of administration in randomized controlled trials and is likely obtained by enhancing the tone of the descending pain inhibition pathways of the central nervous system. ⋯ Studies have also suggested that pain associated with major depressive disorder can be reduced with this medication. Modest effects for headache, osteoarthritic pain, and pain secondary to Parkinson disease have also been documented, but data are obtained from single-blinded or open-label trials that require further corroboration with larger randomized studies. Duloxetine has not yet been directly compared with other antidepressants or anticonvulsants for the treatment of pain syndromes.
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Lidocaine, a local anesthetic and antiarrhythmic drug that alters depolarization in neurons by blocking the fast voltage-gated sodium (Na+) channels in the cell membrane, is used for regional anesthesia, as antiarrhythmic drug, and as analgesic for various painful conditions. It is unclear whether monotherapy with intravenous lidocaine has an analgesic effect in healthy individuals. To address this important question, we studied pain perception before, during, and after the administration of intravenous lidocaine in 16 human volunteers. Our hypothesis was that lidocaine, administered as a short intravenous infusion, does not have an analgesic effect in healthy volunteers. ⋯ The observed sustained analgesic effect of systemic lidocaine in the ischemic pain model suggests that lidocaine may be used to treat acute pain.
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Reg Anesth Pain Med · May 2010
Revisiting anatomic landmarks: lateral popliteal approach for sciatic nerve block based on magnetic resonance imaging.
When the conventional lateral popliteal sciatic nerve (SN) block is performed, the needle angle required to localize and the level of the SN bifurcation are highly variable. The aim of our magnetic resonance imaging (MRI) study was to determine the most common range of needle-insertion angles and the relationship between skin-to-femur distance and angle. We also evaluated the variability of the SN bifurcation level and the relationship between patient height and nerve bifurcation level. ⋯ Our simulated lateral popliteal SN block on MRIs shows a 15- to 45-degree range of needle-insertion angles. As the skin-to-femur distance was greater than 4.5 cm, the angles were progressively smaller than 30 degrees. Although this was an MRI study, it does provide some evidence that indicates the conventional clinically recommended 25- to 30-degree-angle ranges may need to be reevaluated. Needle insertion of 10 cm or greater proximal to the popliteal crease may increase the chance of placement at or proximal to the SN bifurcation.