Is lumbar erector spinae plane block (L-ESPB) a lumbar plexus block?: a case report of three cases

Background Lumbar erector spinae plane block (L-ESPB) is being used in fractured hip patients for the postoperative pain relief and as a sole anesthetic technique. Various clinical and cadaveric studies have differences of opinion about its mechanism of action and pathways of local anesthetic spread; however, the role of lumbar plexus (LP) in the mechanism of action is still not considered. In our clinical experience, we observed that the action on LP could be a pathway for the analgesic action of local anesthetic along with paravertebral spread. Case presentation We report here three cases of the fractured hip who were given L-ESPB for postoperative pain management. The radiological examination was done after injection of non-ionic contrast to know the spread of local anesthetic. In two cases, the contrast spread was seen towards LP and in one case spread of contrast was observed towards the paravertebral area. Conclusions Effect of local anesthetic on the lumbar plexus is one of the plausible pathways in L-ESPB for its analgesic mechanism of action.

Schild analysis of the interaction between parthenolide and cocaine on their effects on planarian motility suggests an orthosteric relationship.

One of the best-characterized planarian behaviors induced by various compounds is the change in locomotor velocity. Previous work from our laboratory showed that the sesquiterpene lactone parthenolide and the local anesthetic cocaine, reduce planarian motility. Parthenolide reverses the cocaine-induced motility decrease and vice versa. However, the exact mechanism of the cocaine/parthenolide antagonism for this specific planarian behavior is still unknown. Here we report the results of a Schild analysis to determine whether the parthenolide/cocaine relationship is orthosteric or allosteric. Our results suggest an orthosteric relationship between these two compounds in the planarian Girardia tigrina. The simplest interpretation of our data is a shared binding site for cocaine and parthenolide. Still, we cannot rule out the possibility of distinct yet overlapping binding sites with the data available.