Role of an Intercostobrachial Nerve Block in Alleviating Tourniquet Pain: A Randomized Clinical Trial

Abstract

Introduction Tourniquet pain may have cutaneous and ischemic components. It is questionable whether blockade of a sensory nerve will help reduce ischemic pain. In addition, complete anesthesia of the axilla in the intercostobrachial nerve (ICBN) distribution is challenging to execute, and ICBN blockade has an inherently higher failure rate because of its variable anatomic location and source of innervation. We sought to determine the utility of an ICBN block for the prevention of tourniquet pain. Methods We conducted a single-center randomized controlled trial at a major academic medical center involving patients scheduled to undergo distal upper extremity surgery under ultrasound-guided supraclavicular brachial plexus block. Forty patients were randomized to receive an additional ICBN block or no ICBN block, with 22 allocated to the intervention and 18 to control. We collected data on the incidence of tourniquet pain and systemic anesthetic requirements. Results Initial contingency analysis examining the relationship between ICBN block placement and the development of pain using the two-tailed Fisher exact test failed to show that the presence or absence of ICBN block was associated with the development of tourniquet pain. χ² analysis failed to show that tourniquet time was significantly related to the development of tourniquet pain. Conclusions The overall incidence of tourniquet pain in the setting of a dense supraclavicular brachial plexus block for surgical anesthesia was low even without an ICBN block and even with tourniquet times greater than 90 min. Tourniquet pain was easily managed with small amounts of systemic analgesics.

Keywords: brachial plexus block; intercostal nerves; nerve block; pain; tourniquets.

Figure 1. CONSORT flow diagram.

Figure 2. Development of pain between groups.

Initial contingency analysis examining the relationship between intercostobrachial nerve (ICBN) block placement and the development of pain using the two-tailed Fisher exact test demonstrated that the presence or absence of the ICBN block was not significantly associated with the development of tourniquet pain (p = 0.31). When examined again using a one-tailed Fisher exact test to examine the probability that tourniquet pain was more likely in patients not receiving the ICBN block, the results remained statistically nonsignificant (p = 0.23).