Background and objectives Lumbar plexus block has been used to provide postoperative analgesia after lower limb surgery. The fascia iliaca compartment block (FICB) has been proposed as an anterior approach of the lumbar plexus targeting the femoral, obturator and lateral femoral cutaneous nerve. However, both radiological and clinical evidence demonstrated that an infra-inguinal approach to the fascia iliaca compartment does not reliably block the three target nerves.
We hypothesized that a supra-inguinal approach of the fascia iliaca compartment results in a more consistent block of the three target nerves than an infra-inguinal approach.
Methods We performed a randomized controlled, double-blind trial in 10 healthy volunteers. Both an infra-inguinal FICB (I-FICB) and a supra-inguinal FICB (S-FICB) were performed on the left or the right side in each volunteer. Forty milliliters of lidocaine 0.5% was injected with each approach. Sensory and motor block and spread of local anesthetics (LA) on MRI were assessed.
Results After an S-FICB, 80% of the volunteers had a complete sensory block of the medial, anterior and lateral region of the thigh, compared with 30% after an I-FICB (p=0.035). There was an insignificant effect on motor function with both approaches. After an S-FICB, in 8 out of 10 volunteers there was spread of LA in the expected anatomic location of the obturator nerve on MRI compared with 1 out of 10 volunteers after an I-FICB (p=0.0017). The cranial spread of LA after an S-FICB on MRI was higher than after an I-FICB (p=0.007), whereas there was a more caudal spread of LA on MRI after an I-FICB than after an S-FICB (p=0.005).
Conclusions An S-FICB produces a more complete sensory block of the medial, anterior and lateral region of the thigh, compared with an I-FICB. Our study demonstrates that an S-FICB with 40 mL of LA more reliably spreads LA to the anatomical location of the three target nerves of the lumbar plexus on MRI than an I-FICB. An S-FICB also leads to a more consistent spread in a cranial direction under the fascia iliaca and around the psoas muscle.
Clinical trial registration This work was registered with the European clinical trial registry: Identifier Eudra CT 2015-004607-24.
- lower extremity
- truncal blocks
- interventional pain management
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KV and MD are joint first authors.
KV and MD contributed equally.
Contributors KV and MD contributed to the first draft of paper and finalization of the final draft. KV, MD and IL contributed to the study design and study conduct. IL contributed to the literature research and graphics. IL, FS, DC, BC and PS contributed to the data analysis. BC and PS radiological support (MRI-scan) and study conduct. IL, FS, DC, AN, MVDV and AH contributed to the critical appraisal of the final draft.
Funding The Department of Anesthesiology of UZ Leuven funded this study. KV received a grant from ESRA (European Society of Regional Anesthesia) in 2016 for his PhD research but this did not affect this study.
Competing interests None declared.
Patient consent for publication Obtained.
Ethics approval Local ethics committee (Hospital AZ Groeninge, Kortrijk nrAZGS2016021) and the Belgian Federal Agency for Medicines and Health Products (FAMHP).
Provenance and peer review Not commissioned; externally peer reviewed.