Thoracic fascial plane injections using a ‘hit-rib’ technique in dog cadavers targeting lateral cutaneous nerves

Objective

To identify the feasibility of the anatomical landmark-guided ‘hit-rib’ technique for distributing injectate solution in the thoracic lateral cutaneous fascial plane (TLC_PLANE) and to evaluate injectate dispersion.

Study design

Prospective, experimental, randomized cadaveric study.

Animals

A group of 10 adult Beagle dog cadavers.

Methods

In three cadavers, the feasibility of TLC_PLANE dispersion of injectate was evaluated using the hit-rib technique. Hypodermic needles (23 or 26 gauge) were inserted perpendicularly through the skin until contact was made with target ribs (fourth, seventh, and 10th ribs), and 1 mL of bupivacaine-methylene blue dye solution was injected. In seven cadavers, injectate dispersion was evaluated following injection of dye solution using the same technique with 23 gauge hypodermic needles. For each hemithorax, a total injectate volume of 0.4 mL kg^-1 was divided equally among the three injection sites. Duration of each injection was recorded. Injectate dispersion was evaluated through dissection. Data were analyzed descriptively and the results presented as median (range).

Results

The hit-rib technique appeared feasible, with injectate successfully distributed in the hemithoraces of the three cadavers as follows: all injections distributed within the TLC_PLANE; at the fourth and seventh ribs, it reached the superficial and deep serratus planes with 23 and 26 gauge hypodermic needles, respectively. From the injectate dispersion assessment, in each hemithorax, injectate was confirmed to be distributed in the TLC_PLANE, with dispersion from ribs number 2 (1–3) to 12 (11–12). The numbers of stained lateral cutaneous branches for each injection site were 4 (3–5), 4 (4–5), and 4 (3–5) at the fourth, seventh, and 10th ribs, respectively. The procedure time per hemithorax was 42.6 (28.8–60.7) seconds.

Conclusions and clinical relevance

This first description of an anatomical landmark-guided thoracic lateral cutaneous fascial plane block technique potentially results in injectate spread to the entire hemithorax with three simple and quick-to-perform injections.