Regional anesthesia
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The object of this study was to measure the clinically relevant depth of the posterior epidural space (ES) while placing subarachnoid catheters. ⋯ The posterior ES has been found to be somewhat larger and more variable than previously described. The findings provide clinical confirmation of recent radiologic and cadaveric studies, which portray a posterior ES of variable size and complex shape. These findings have implications for cannulation and use of epidural therapy as well as for the combined catheter epidural and single-dose spinal technique.
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Regional anesthesia · Sep 1996
Epidural anatomy examined by cryomicrotome section. Influence of age, vertebral level, and disease.
Cryomicrotome section is a means of anatomic examination with minimal artifact ideally suited to delineating details of tissue relationships in the epidural space. In the past, healthy adult lumbar levels have been studied by this method. This report extends observations to other regions of the vertebral column, other age groups, and some abnormal conditions. ⋯ Variations in epidural anatomy due to vertebral level, age, and disease may alter the ease of epidural entry and passage of catheters and injected solution.
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Regional anesthesia · Sep 1996
Subarachnoid bupivacaine increases human cerebrospinal fluid concentration of serotonin.
Serotonin (5-hydroxytryptamine [5-HT]) has antinociceptive properties at the spinal level. Activation of descending serotonergic neurons or topically applied 5-HT at the spinal cord inhibits rostral spread of sensory information. Epidural anesthesia has been shown to increase 5-HT in plasma, and local anesthetics may interfere with 5-HT reuptake and metabolism. For these reasons, the action of subarachnoid local anesthetics on cerebrospinal fluid (CSF) 5-HT concentrations has been studied. ⋯ Subarachnoid bupivacaine increases local 5-HT concentration. This may have implications for nociceptive gating as well as for local vasoregulation.
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Regional anesthesia · Sep 1996
Anatomic considerations for sciatic nerve block in the popliteal fossa through the lateral approach.
The disadvantage of the classic posterior approach to block of the sciatic nerve at the knee level (popliteal nerve block [PNB]) is the need to position a patient in the prone position for performance of the block. In this study on cadavers, a lateral approach to the popliteal nerve in the supine position was investigated, and some anatomic considerations of relevance to popliteal nerve block were addressed. ⋯ A lateral approach to the popliteal nerve with insertion of the needle at a 30 degrees angle relative to the horizontal plane results in predictable approximation of the needle tip to the popliteal nerve. The results also suggest the existence of a continuous neural sheath encompassing the popliteal nerve and its main branches. This may have clinical implications similar to those in perivascular neuronal block.