A novel technique of ultrasound-guided lateral cutaneous branch of the iliohypogastric nerve block: A cadaveric study

Background The lateral cutaneous branch of the iliohypogastric nerve (LCBIN) block combined with the lateral femoral cutaneous, superior cluneal and subcostal nerve blocks has been shown to provide complete anaesthetic coverage for the incisions used for hip arthroplasty. Successful ultrasound-guided selective nerve blocks have been described for these nerves, except for the LCBIN. The objective of this cadaveric study was to determine the position of the LCBIN in order to provide the anatomical basis for an ultrasound-guided nerve block approach. Furthermore, we aimed to evaluate the spread of injected dye after using the ultrasound-guided nerve block approach. Methods The LCBIN and its relationship with iliac crest (IC) was assessed bilaterally in 27 adult cadaveric dissections. Bilaterally, in two cadavers, an ultrasound transducer was applied transversely above the IC and moved in caudal or cranial direction to identify the LCBIN. A needle was inserted in-plane and 3 ml of a solution with methylene blue was injected and confirmed by dissection. Results The mean distance from the anterior superior iliac spine to the point where the LCBIN crossed the IC was 9.74 +/- 0.84 cm. The mean distance from the point where the nerve pierced the aponeurosis of the external oblique muscle to the point where it crossed the IC was 0.59 +/- 0.77 cm. The nerve was easily visualised in 3 out of 4 sides using ultrasound. However, the nerve was coloured in all cases. Conclusion The present study showed that the LCBIN has a constant location and is sonographically easy visualized in a well-defined anatomical space. Thus, the ultrasound guided LCBIN block may be an alternative to the blind injection technique.