Ultrasound-guided 'two-in-one' femoral and obturator nerve block in the dog: an anatomical study.
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).


METHODS
Prospective experimental trial.


METHODS
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
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.
Department of Animal Health, Faculty of Veterinary Medicine and Zootechny, Universidad del Tolima, Ibagué, Colombia.
Diego F
DF
Echeverry
Francisco G
FG
Laredo
Francisco
F
Gil
Eliseo
E
Belda
Marta
M
Soler
Amalia
A
Agut
D000779:Anesthetics, Local / Q000008:administration & dosage; D000818:Animals; D002102:Cadaver; D004285:Dogs; D005267:Femoral Nerve / Q000033:anatomy & histology*; D008012:Lidocaine / Q000008:administration & dosage; D009407:Nerve Block / Q000379:methods / Q000662:veterinary*; D009776:Obturator Nerve / Q000033:anatomy & histology*; D018084:Ultrasonography, Interventional / Q000379:methods / Q000662:veterinary*
D000779:Anesthetics, Local; D008012:Lidocaine