Anatomical characterization of the canine brachial plexus block and evaluation of three blind brachial plexus block techniques

This thesis describes the ventral spinal rami that contribute to the formation of the brachial plexus and its peripheral nerves in cadaver dogs and evaluated three blind techniques for performing the brachial plexus block. In phase I of this study the region of the brachial plexus of cadaver dogs was injected using one of three blind approaches for performing the brachial plexus block. The brachial plexus was then dissected to evaluate the resultant nerve staining followed by dissection and identification of the nerves that formed the brachial plexus. In phase II of this study the degree of anesthesia and analgesia that resulted from each of the three approaches for performing the brachial plexus block were evaluated in clinical cases of dogs undergoing surgical procedures of the thoracic limb. Phase I of this study identified that the canine brachial plexus in this group of dogs was formed from the ventral spinal nerve rami of C6, C7, C8 and T1. Additionally, three anatomical landmarks were identified as fundamental for successful dye injection at the level of the brachial plexus. These landmarks were the transverse process of C6, the point of the shoulder, and the first rib. No differences in dye dispersion and nerve staining were identified between the three blind brachial plexus block techniques. The clinical phase, phase II, of this study did not identify any differences between the three approaches to block the brachial plexus and the resultant postoperative pain scores in dogs undergoing surgical procedures of the thoracic limb. Additionally, blockade of the brachial plexus provides better analgesia in dogs undergoing surgical procedures of the distal thoracic limb than dogs undergoing thoracic limb amputation.