Comparison of two blind brachial plexus blocks in goat cadavers

Abstract

Objective: This study aimed to compare two approaches to the brachial plexus: the traditional blind method and an additional technique, both of which use anatomical landmarks to guide needle insertion.

Materials and methods: The traditional and additional approaches were performed on both thoracic limbs of 24 cadavers (24 for each approach). Methylene dye is used for injection and nerve staining. We counted the nerves that successfully stained (staining less than 1 cm). The Mann-Whitney U test was used to compare approaches.

Results: The findings indicated that all cadavers were successfully used. The traditional approach and the additional approach revealed success rates of 45.83% and 54.17%, respectively. We found no significant differences between the two techniques (p > 0.05).

Conclusion: The additional approach presents a viable alternative to the traditional method for performing the brachial plexus block in goats. Further research into the clinical differences between these techniques could lead to useful insights that help make them more accurate and useful.

Keywords: Additional approach; brachial plexus block; goat cadaver; methylene blue; traditional approach.

Figure 1.. Illustration of the traditional approach (blue needle) and the additional approach (red needle) to the brachial plexus nerve block in goat cadavers. Note that in the traditional approach (blue arrow), the needle is introduced at the midpoint between the acromion process (A) and the point of the shoulder or greater tubercle of the humerus (B). In the additional approach (red arrow), the needle is introduced both cranial and caudal at the midpoint between the acromion process (A) and the point of the shoulder or greater tubercle of the humerus (B).

Figure 2.. Example of brachial plexus scoring of methylene blue stain distribution after injection using two approaches for needle insertion: (a) goat 16: traditional approach, staining score I with lack of staining of any nerve with axillary injection of dye; (b) goat 5: additional approach, staining score III with dye stain of suprascapular, subscapular, musculocutaneous, and median nerves; (c) goat 8: traditional approach, staining score V with staining of all nerves; (d) goat 21: additional approach, staining score V with staining of all nerves. 1, musculocutaneous n.; 2, median n.; 3, ulnar n.; 4, thoracodorsal n.; 5, radial n.; 6, axillary n.; 7, suprascalular n.; 7*, supraspinatus m.; 8, serratus ventralis m.; 9, subscapular n.