Ultrasound Guidance Intercostobrachial Nerve Block in AVF Superficialization

Patients with chronic renal failure, particularly those with end-stage kidney disease, usually have multiple co-morbid conditions, and thus, regional anesthesia is usually preferred over general anesthesia (GA) in such cases Arteriovenous fistula (AVF) superficialization is a critical surgical procedure commonly performed in patients with end-stage renal disease to facilitate adequate hemodialysis access Ultrasound-guided brachial plexus block provides excellent surgical anesthesia for upper extremity procedures and is widely used during (AVF) creation. However, superficialization of the fistula often requires an extended incision and deeper dissection along the medial aspect of the arm. Because the intercostobrachial nerve (ICBN) originates from the second intercostal nerve (T2) rather than the brachial plexus, brachial plexus block alone does not provide reliable anesthesia of the axilla and upper medial arm supplied by the ICBN The skin and subcutaneous tissue in this specific region are heavily innervated by the ICBN, which originates as the lateral cutaneous branch of the second intercostal nerve (T2) and bypasses the brachial plexus entirely. Consequently, brachial plexus alone may not provide adequate anesthesia of the medial upper arm. So patients undergoing this procedure often experience sharp and intense intraoperative pain during medial skin tunneling and surgical manipulation if the ICBN is not separately anesthetized To address this anatomical challenge, ICBN block must be performed in conjunction with the primary brachial plexus blockade. Traditionally, a conventional landmark-guided subcutaneous infiltration has been used to block the ICBN as it emerges into the axillary fossa. However, this blind technique exhibits variable success rates and carries a risk of incomplete sensory coverage, and can lead to accidental vascular puncture in the highly vascular axillary region (Magazzeni et al., 2018). With the advancement of regional anesthesia, ultrasound-guided fascial plane blocks several approaches have been described, including , ultrasound-guided distal block, proximal block at the chest wall, and fascial plane techniques, with variable success rates reported among studies. One possible explanation for these inconsistent results is the considerable anatomical variability of the ICBN. Cadaveric studies have demonstrated variations in its origin, branching pattern, and communications with adjacent nerves. Furthermore, approximately one-third of ICBNs may receive contributions from neighboring intercostal nerves, potentially limiting the effectiveness of localized distal injections.In a randomized trial, Moustafa and Kandeel reported a complete sensory block success rate of only 51% using a distal ultrasound-guided ICBN block with 6 mL of local anesthetic, suggesting that distal blockade may not reliably anesthetize all relevant nerve branches. Given the considerable anatomical variability of the ICBN and its terminal branches, the extent of local anesthetic spread may influence the success of distal ICBN blockade. It is therefore plausible that larger injectate volumes may improve neural coverage and increase the probability of achieving complete sensory blockade. This hypothesis has not been specifically evaluated in previous clinical studies.