Ultrasound-guided ‘two-in-one’ femoral and obturator nerve block in the dog: an anatomical study

Authors

  • Diego F Echeverry,

    1. Department of Animal Health, Faculty of Veterinary Medicine and Zootechny, Universidad del Tolima, Ibagué, Colombia
    2. Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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  • Francisco G Laredo,

    1. Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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  • Francisco Gil,

    1. Department of Veterinary Anatomy and Embryology, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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  • Eliseo Belda,

    1. Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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  • Marta Soler,

    1. Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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  • Amalia Agut

    1. Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
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Francisco Laredo, Department of Animal Medicine and Surgery, Faculty of Veterinary, University of Murcia, Espinardo 30100, Murcia, Spain. E-mail: laredo@um.es

Abstract

Objective  To evaluate the dye extent and distribution at the lumbar plexus (LP) of three volumes of local anaesthetic-methylene-blue solution administered close to the femoral nerve (FN) by the use of a ventral ultrasound (US)-guided suprainguinal approach (SIA).

Study design  Prospective experimental trial.

Animals  Twenty mongrel canine cadavers weighing 17.7 ± 3.8 kg (mean ± SD).

Methods  The left and right LP of two cadavers were dissected to identify the FN, obturator nerve (ON) and lateral femoral cutaneous nerve (LFCN). The extent and distribution of dye at the LP of each of three volumes of injectate of 0.2, 0.4 and 0.6 mL kg−1 administered close to the FN by a ventral US-guided SIA then were studied in a further 18 dog cadavers (n = 6 per group). Staining of ≥2 cm along the target nerves was indicative of sufficient spread to produce a nerve block.

Results  The ventral US-guided SIA allowed the observation of the FN within the iliopsoas muscle (IPM) in a total of 17 cadavers. The assessment of the dye extent and distribution revealed a similar pattern regardless of the injected volume. From the injection site, the spreading of injectate occurred in cranial, lateral and caudal directions. The FN and ON were effectively stained in all the cases. The LFCN was not effectively stained in any case.

Conclusions and clinical relevance  A volume of 0.2 mL kg−1 administered close to the FN by a ventral US-guided SIA produced a sufficient distribution of the injectate within the IPM to produce effective staining of the FN and ON. This US-guided technique may be an appropriate alternative to previously reported techniques based on electrolocation to block the FN and ON in the dog.

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