Backgrounds Ultrasound-guided proximal and distal approaches of the intercostobrachial nerve (ICBN) blocks facilitate analgesia for upper arm and axillary surgery, though success rates vary and lack clinical comparison. This study compared their anesthetic and analgesic efficacy as an adjunct to the supraclavicular brachial plexus block for upper arm arteriovenous access surgery.

Methods 60 end-stage renal disease patients undergoing upper arm arteriovenous access were randomly assigned to receive either proximal or distal ICBN block using 10 mL of a mixture of levobupivacaine and lidocaine with epinephrine. The primary outcome was a successful ICBN block, defined as a cutaneous sensory blockade at both the medial upper arm and axilla 30 min after the block. Secondary outcomes included block performance, block-related complications, rate of surgical anesthesia, and postoperative analgesia.

Results The proximal approach had a higher percentage of sensory blockade at the axilla (96.7% vs 73.3%, p=0.03), but comparable rates at the medial upper arm (96.7% vs 96.7%, p=1.00). Consequently, the proximal approach had a higher overall success rate (96.7% vs 73.3%, difference: 23.3%; 95% CI: 6.3%, 40.4%; p=0.03). Both groups had similar surgical anesthesia rates of 93.3%. No significant differences were found in performance time, procedural pain, or postoperative pain intensity.

Conclusions Proximal ICBN block consistently reduced sensation in the medial upper arm and axilla, while one-quarter of distal blocks spared the axilla. Both approaches, in combination with a supraclavicular brachial plexus block, were effective for upper arm arteriovenous access procedures. However, the proximal approach may be preferable for axillary surgery.

Trial registration number TCTR20200730006.