Revival of old local anesthetics for spinal anesthesia in ambulatory surgery

In recent years, several older (first intrathecal use in the 1950s, 1960s, and 1970s) local anesthetics have been investigated as spinal anesthetics in ambulatory surgery because these drugs are claimed to cause less transient neurologic symptoms (TNS) than lidocaine which was the main spinal anesthetic for surgery of short-duration for decades. The review covers the current literature. Several recent reports have dealt with the short-acting chloroprocaine and articaine and the intermediate-duration-acting prilocaine. Mepivacaine, another intermediate-acting drug, was applied in one trial only. Various dosages of these drugs either alone or with a small dose of fentanyl were compared with each other, with lidocaine, or with the currently most commonly used low-dose bupivacaine technique. The recovery from both motor and sensory block was usually reasonably fast. However, occasionally recovery after mepivacaine and prilocaine was prolonged which fits ill in a fast-flow ambulatory setting. TNS cases were very rarely reported. The newest results corroborate (at least for chloroprocaine, articaine, and prilocaine) previous data that these drugs provide reliable and mostly well tolerated spinal blocks associated with an apparently smaller risk for postanesthesic TNS as compared with lidocaine. Further studies are warranted regarding broader indications, possible usefulness of adjuvants, and for the exploration of the side-effect profiles in detail. To what extent the observed revival of these older, rather well characterized local anesthetics leads to a wider use of spinal anesthesia in the ambulatory setting remains to be seen. This is also dependent on various organizational and local traditional factors.