• truncal blocks
• acute pain
• postoperative pain
• pain medicine

To the Editor

We would like to thank Piraccini et al very much for their opinions on our article.1 They argue that the superior costotransverse ligament (SCTL) plays a key role in the success of the block. In anatomic studies, SCTL structure has been shown to be permeable. It also appears that the lateral part is free allowing drug access to the paravertebral space. When the anatomical structure of SCTL is examined under ultrasound, it is understood that the ligament is located obliquely between the transverse process and the ribs. Furthermore, there is no equal distance to both transverse processes in the plane between the two transverse processes.2 In this case, the distances between two consecutive transverse processes and the paravertebral space should not be expected to be equal. Kılıçaslan et al specified the posterior part of the transverse process under the intertransverse ligament as the injection site in the substransverse process interligamentary (STIL) plane block.3 At this point, there is the SCTL adhesion point and injection can be associated with the paravertebral area. In our practice, we use a dual injection technique for the Erector Spinae Plane Block (ESPB) which is different from the STIL block. In addition to the classic ESPB, we suggest a second injection above the SCTL under the intertransverse ligament. The important thing is that the needle is below the intertransverse ligament and far from the pleura. It is the closest possible localization of the local anesthetic to SCTL; we believe it facilitates the transition of the drug to the paravertebral area.4

In addition, we think that there is no clear information indicating the benefit and harm of steroid use in terms of increasing the chemical permeability as stated in the Piraccini article. Cell membrane fluidity is a complex concept and it is known that flow rate can be limited by dexamethasone use.5

Pressure from physical methods may be another important parameter in order to increase the amount of local anesthetic passing into the paravertebral area. The clinical significance of the change in pressure in the SCTL ligament during the fascial plane block is not clear. Patients have pain complaints injections with high pressure and we think that we need to study more about the positive or negative results of pressure variations between fascial plans.