Articles: nerve-block.
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Anesthesia and analgesia · Oct 2003
The acute myotoxic effects of bupivacaine and ropivacaine after continuous peripheral nerve blockades.
Bupivacaine causes muscle damage. However, the myotoxic potency of ropivacaine is still unexplored. Therefore, we performed this study to compare the effects of bupivacaine and ropivacaine on skeletal muscle tissue in equipotent concentrations. Femoral nerve catheters were inserted into anesthetized minipigs, and 20 mL of either bupivacaine (5 mg/mL) or ropivacaine (7.5 mg/mL) was injected. Subsequently, bupivacaine (2.5 mg/mL) and ropivacaine (3.75 mg/mL) were continuously infused over 6 h. Control animals were treated with corresponding volumes of normal saline. Finally, muscle samples were dissected at injection sites. After processing and staining, histological patterns of muscle damage were blindly examined, scored (0 = no damage to 3 = myonecrosis), and statistically analyzed. After normal saline, only interstitial edema was found. Bupivacaine treatment caused severe tissue damage (score, 2.3 +/- 0.7), whereas ropivacaine induced fiber injury of a significantly smaller extent (score, 1.3 +/- 0.8). Furthermore, bupivacaine, but not ropivacaine, induced apoptosis in muscle fibers. In summary, both drugs induce muscle damage with similar histological patterns. Compared with bupivacaine, which induces both necrosis and apoptosis, the tissue damage caused by ropivacaine is significantly less severe. We conclude that ropivacaine's myotoxic potential is more moderate in comparison with that of bupivacaine. ⋯ After continuous peripheral nerve blockades, the long-acting local anesthetics bupivacaine and ropivacaine both induce fiber necrosis in porcine skeletal muscle tissue. In comparison with ropivacaine, bupivacaine causes tissue damage of a significantly larger extent and additionally induces apoptosis in skeletal muscle cells.
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Facet or zygapophysial joint blocks are used extensively in the evaluation of chronic spinal pain. However, there is a continuing debate about the value and validity of facet joint blocks in the diagnosis of chronic spinal pain. The value of diagnostic facet joint injections may have been overlooked in the medical literature. ⋯ The diagnostic accuracy of controlled local anesthetic facet joint blocks is high in the diagnosis of chronic spinal pain.
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The purpose of this review is to present recent research into the clinical use of regional anaesthesia techniques in ambulatory surgery. Further, to put into an ambulatory perspective some of the issues recently discussed on the basis and practice of regional anaesthesia in general. ⋯ Loco-regional techniques are well suited for ambulatory surgery due to less postoperative nausea and pain and possibly less cognitive dysfunction. The different techniques are continuously being refined in order to provide fast discharge readiness, while still maintaining the benefits.