The right plane for drug injection in ultrasound-guided erector spinae plane block.

Sir,

We would like to thank the authors for the interest in our correspondence.

A very important point has been highlighted regarding the injection point of erector spinae plane block. We have injected the drug deep to the erector spinae muscle (as clear in the figure though wrongly quoted in the text, we stand corrected).[1]

We would like to clarify that for erector spinae plane block, local anaesthesia was injected both deep to the erector spinae muscle and also in between the erector spinae muscle and rhomboideus major muscle (both are called erector spinae plane block). Both the planes had shown comparable analgesic effects in living subjects. Forero et al. compared both the approaches in living individuals and in cadavers.[2] When drug was injected deep to the erector spinae muscle in cadavers, there was more extensive spread of the drug reaching dorsal and ventral rami. However, in living individuals, a good analgesic effect was observed even when it was injected in between rhomboideus major and erector spinae. They postulated that in living subjects, there is more dynamic and extensive spread of drug along tissue planes, perhaps following the course of the medial branch of the dorsal rami which allowed the drug to reach ventral rami.[2] There are additional benefits of inserting drug deep to the erector spinae muscle in which we assume transverse process as a convenient sonographic landmark and backstop for needle advancement, contributing to the ease and safety of the block.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.