• fascia iliaca. fascia iliaca compartment block. regional anesthesia

To the editor,

We read with great interest, the article ‘Supra-inguinal injection for fascia iliaca compartment block results in more consistent spread towards the lumbar plexus than an infra-inguinal injection: a volunteer study’ by Vermeylen et al.1 After the first description of an ultrasound-guided in-plane suprainguinal fascia iliaca compartment block (S-FICB) by Hebbard et al,2 several studies on this approach have emerged. In 2017, a study by Desmet et al3 demonstrated that an ultrasound-guided in-plane S-FICB with a larger volume (40 mL) local anesthetic resulted in a significant reduction of morphine consumption after total hip arthroplasty. In 2018, a pilot study by Vermeylen et al4 suggested that during an ultrasound-guided in-plane S-FICB, the volume of 40 mL was the best compromise to reach the femoral nerve, obturator nerve, and lateral femoral cutaneous nerve in one time. The most recent study by Vermeylen et al1 demonstrated that an ultrasound-guided in-plane S-FICB also led to a more consistent spread in a cranial direction under the fascia iliaca and around the psoas muscle than an infrainguinal injection.

In 2017, Michael Bullock et al5 described a novel ultrasound-guided out-of-plane S-FICB, which was different from the in-plane S-FICB described by Hebbard et al.2 They pointed out that the body mass of North American patients could make the in-plane S-FICB approach challenging. With respect to these two approaches, we have done a lot of practice during lower extremity surgeries. We find that the out-of-plane approach by Michael Bullock et al5 is easy to be hindered by the patient’s breathing especially in obese patients. As the probe is just pressed on the surface of the abdomen, the patient’s breathing inevitably takes the probe up and down as well as the needle, which makes it really difficult to keep the probe stable and the needle fixed just deep to the fascia iliaca, especially in obese patients. Nevertheless, during our practice, the in-plane approach by Hebbard et al2 seems to be less hindered by the patient’s breathing. In that case, the probe is pressed on the inguinal crease and the needle is inserted inferior to the inguinal crease. The two sites are nearly outside of the territory of abdomen, so that the breathing does not impede the probe and the needle is kept stable. In regard to the influence of patient’s breathing, we prudently consider the in-plane approach described by Hebbard et al2 is preferable in obese patients undergoing lower extremity surgery with an ultrasound guided S-FICB.