In response to-Quadratus lumborum block failure: "A must know complication".

Sir,

We read the article “Suri A, Sindwani G, Sahu S, Sureka S. Quadratus lumborum block failure: A must know complication. Indian J Anaesth 2017;61:1016-8”.[1] and give our compliments to the authors for reporting a complication during quadratus lumborum block and its successful management. However, there are few points in this article, which need further clarification.

First, authors have mentioned four variants of quadratus lumborum block; however, only three types (QL-1, 2, and 3) are described by the authors. Second, the reference Figure 1 is showing approach of QL-1; however, authors have mentioned this as approach of QL-3 (transmuscular approach) that needs correction.

Figure 1

Ultrasound guided quadratus lumborum block. EO: External oblique muscle, IO: Internal oblique muscle, TA: Transverse abdominis muscle, QL: Quadratus lumborum muscle, TLF: Thoracolumbar fascia

In this article authors have mentioned that, the block would have failed as catheter tip was seen on quadratus muscle due to tear in lumbar fascia during surgery. However, analgesia was achieved when QL-3 approach was used. It is surprising because the endpoint of QL-1 (technique used by author at first instance) where the tip of catheter must have been resting, is a part of deep recess covered by peritoneum extends between the abdominal wall muscles and the psoas major muscle to the anterior side of the QL muscle. The same peritoneal recess extends laterally between QL and psoas muscles.[2] If that was punctured then there is always a possibility of leak of local anesthetic into peritoneal cavity. If it is insignificant then the first technique would have been effective as QL-3 (used later).

In our opinion, more objective observation like, failure to pain relief in postoperative period after first technique and, further evidence by contrast study would have given answer that is more definitive.

Finally, we think it is not the complication of quadratus lumborum block itself rather; this observation gives an information that, transmuscular quadratus lumborum block is a better option than QL-1 in laparoscopic nephrectomy surgery.

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