Articles: nerve-block.
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Clinical Trial
Factors affecting the spread of bupivacaine in the adult thoracic paravertebral space.
Factors affecting the spread of bupivacaine in the paravertebral space were investigated in patients undergoing paravertebral nerve blocks for the treatment of chronically painful conditions. Injections of bupivacaine 0.5%, 10-15 ml mixed with depomedrone up to 80 mg were repeated at 2-wk intervals up to a maximum of four times. A blinded observer mapped out the subsequent distribution of sensory loss to cold on both sides of the torso at 5-min intervals after each injection. ⋯ A single bolus of bupivacaine produces a safe but unpredictable block. Yet to be defined physical properties and anatomical factors are probably key determinants of the spread of bupivacaine in the paravertebral space. This single bolus technique may be better supplanted by a reversion to the older multiple level injection technique.
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Comparative Study
Prolonged duration local anesthesia from tetrodotoxin-enhanced local anesthetic microspheres.
There is interest in developing prolonged duration local anesthesics. Here we examine whether tetrodotoxin (TTX) can be used to prolong the block from bupivacaine microspheres with and without dexamethasone. Rats received sciatic nerve blocks with 75 mg of microspheres containing 0.05% (w/w) TTX, 50% (w/w) bupivacaine and/or 0.05% (w/w) dexamethasone. 0.1% (w/w) TTX microspheres were also tested. ⋯ In summary, coencapsulation of TTX in controlled release devices containing bupivacaine and dexamethasone resulted in very prolonged nerve blocks. As formulated here, this preparation had a narrow margin of safety. While the myotoxicity appears consistent with the well-known reversible myotoxicity associated with local anesthetics, its long-term significance remains to be established.
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Comparative Study
Variability in determination of point of needle insertion in peripheral nerve blocks: a comparison of experienced and inexperienced anaesthetists.
Accurate identification of surface landmarks is essential for the successful performance of peripheral nerve blocks. The variability between experienced and inexperienced practitioners in identifying anatomical landmarks has not been studied previously. Anaesthetists were asked to identify the point of needle insertion for posterior lumbar plexus and sciatic nerve blocks on a volunteer using a standard textbook description. ⋯ The sciatic nerve block X, Y co-ordinates were 77 [62-99], 70 [49-89] and 68 [29-116], 62 [26-93] in the experienced and inexperienced groups, respectively. The variance for the point of needle insertion was significantly greater in the inexperienced group (p <0.01) for both the lumbar plexus and sciatic nerve blocks. We conclude that with increasing experience, there is decreased variability in determining the point of needle insertion using anatomical landmarks.
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Arch Phys Med Rehabil · Jul 2003
Motor branch of the rectus femoris: anatomic location for selective motor branch block in stiff-legged gait.
To determine the ideal target point for selective motor branch block of the rectus femoris to treat stiff-legged gait. ⋯ The point T is the most suitable target point to selectively block the motor branch of the rectus femoris without affecting the other 3 motor branches of the femoral nerve in the treatment of stiff-legged gait.
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For the repair of an open injury to the hand, a continuous axillary block was performed in a 40- year-old male patient. Slight resistance was experienced during advancement of the catheter. ⋯ Three days later the removal of the catheter proved to be difficult due to a knot in the distal part of the catheter. This seems to be the first report of a knot in a catheter used for continuous axillary plexus block.