Sir,
We would like to thank the authors for taking great interest in our review article. They have correctly pointed that quadratus lumborum block (QLB) needs to be mentioned in recent advances in post-caesarean analgesia. QLB is a new fascial plane block gaining momentum for post-operative analgesia after various abdominal surgeries.
There are two studies on QLB for post-operative analgesia after caesarean section, and both reported QLB to significantly reduce morphine consumption in combination with multimodal analgesia regime.[1,2] In both the studies, posterior approach for QLB was used with the patient in the supine position. The advantages of the posterior approach compared to anterolateral and transmuscular approach are more superficial point of injection, better ultrasonographic resolution and potentially safer injection as intraperitoneal contents are at a further distance.[1] Compared to transversus abdominis plane (TAP) block, QLB has been noted to provide widespread analgesia of longer duration. The sensory levels obtained by QLB were T7 and T12 dermatomes, whereas TAP block affected T10 and T12 dermatomes. This can be explained by spread either in the thoracolumbar plane or into the paravertebral space. The extensive spread has been postulated to provide analgesia for visceral component of pain along with somatic. The duration of analgesia after QLB exceeded 24 h and was significantly longer than that for TAP block.[2] However, the post-operative analgesic regime in both studies included patient-controlled analgesia morphine and the cumulative consumption measured at various intervals could have been affected by use of morphine for non-operative pain. Further studies are required for validation of analgesic efficacy of QLB. Another important consideration is that QLB is purely an ultrasound-guided block and requires a clear knowledge of anatomy for safe performance. A number of vital structures including the kidney and lumbar arteries running behind QL muscle are susceptible to injury. In patients receiving anticoagulant therapy, the QLB should be carefully considered due to the vascularity of area, retroperitoneal spread of haematoma and proximity to paravertebral area and lumbar plexus.[3]
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
REFERENCES
- 1.Blanco R, Ansari T, Girgis E. Quadratus lumborum block for postoperative pain after caesarean section: A randomised controlled trial. Eur J Anaesthesiol. 2015;32:812–8. doi: 10.1097/EJA.0000000000000299. [DOI] [PubMed] [Google Scholar]
- 2.Blanco R, Ansari T, Riad W, Shetty N. Quadratus lumborum block versus transversus abdominis plane block for postoperative pain after cesarean delivery: A randomized controlled trial. Reg Anesth Pain Med. 2016;41:757–62. doi: 10.1097/AAP.0000000000000495. [DOI] [PubMed] [Google Scholar]
- 3.Elsharkawy H. Ultrasound-guided quadratus lumborum block: How do I do it? ASRA News. 2015;15:34–40. [Google Scholar]