Distribution of injectate spread using two approaches for an ultrasound-guided transversus abdominis plane block in cats: a cadaver and computed tomography study

This study compared the distribution of a bupivacaine-iohexol-dye solution administered by one- versus two-point ultrasound-guided transversus abdominis plane (TAP) injection in cats.
Eight cat cadavers were included in a randomized, prospective, blinded, anatomical and computed tomography study. On each side of each cadaver, volumes of 0.5 or 0.25 mL kg^-1 per point of the solution were injected using either one (lateral; TAP-L) or two (subcostal and lateral; TAP-SL) in-plane injection points, respectively. Computed tomography assessed contrast distribution and cranio-caudal spread into the TAP. Anatomical dissection evaluated dye distribution and number of thoracic (T) and lumbar (L) spinal nerves stained >1 cm circumferentially. Student’s t and Mann-Whitney tests were used for statistical analysis (p < 0.05).