Cite as: Novak A, Toeller-DeSimone M, Seering MS. ASRA answers: does an intercostobrachial nerve block alleviate tourniquet pain during upper extremity surgery. ASRA Pain Medicine News 2025;50. https://doi.org/10.52211/asra050125.013.

ASRA Answers

Introduction

The intercostal brachial nerve (ICBN) block is routinely performed in addition to a brachial plexus block for surgeries of the upper medial arm or surgeries distal to the elbow when an upper arm tourniquet is anticipated. Current evidence suggests that the practice of performing an ICBN block to alleviate tourniquet pain may be unnecessary. This ASRA Answers article provides the anatomical and historical context of the ICBN block’s use in clinical practice and explores whether performing this block for tourniquet pain remains warranted.

Literature Review

Upper extremity surgery distal to the elbow commonly involves the use of a pneumatic tourniquet to facilitate minimal blood loss and an improved view of the operative field for the surgical team. The high pressures generated by the tourniquet cause pain at and distal to the tourniquet site approximately 30-45 minutes after sustained insufflation.¹ This pain is commonly described as a vague, dull, or aching sensation and is associated with increased blood pressure.² Pain associated with tourniquet pressure can occur despite a brachial plexus nerve block sufficiently dense for surgical incision. Patients may require supplemental analgesics or conversion to general anesthesia to tolerate this discomfort through the remainder of the surgery.

The ICBN block is routinely used as an adjunct to the brachial plexus nerve block to provide analgesic coverage for this tourniquet-induced pain of the upper extremity.^3,4 Despite this block's use, some patients still report experiencing pain under regional anesthesia, and hemodynamic changes may still be observed after prolonged insufflation.⁴

Although the exact mechanism of how tourniquet pain develops has yet to be fully elucidated, this pain consists of ischemic and cutaneous components.³ The cutaneous origin of tourniquet pain is thought to result from incomplete cutaneous coverage of the arm following brachial plexus blockade, specifically, the medial upper aspect of the arm. The sensory innervation of this area of the upper arm is shared by the medial brachial cutaneous nerve (MBCN), which originates from the medial cord of the brachial plexus, and ICBN, which originates from the lateral branch of the second intercostal nerve.⁴ The MBCN is often adequately covered with a brachial plexus block proximal to the axilla, but the ICBN is not. The origin of ischemic tourniquet pain is thought to be mediated through unmyelinated, slow-conducting C fibers.² This C fiber-mediated pain is challenging to cover as demonstrated by the presence of tachycardia and hypertension in patients, who receive a combination of regional and general anesthesia techniques.⁵ The ischemic component of pain does not appear to be adequately covered by the local anesthetic regional techniques.^4,5

The ICBN block gained popularity among anesthesiologists for upper extremity surgery with the intent of providing surgical anesthesia in the medial upper arm that was not well covered by brachial plexus blocks (eg, upper limb fistula creation axilla dissection).^6-8 This combination of ICBN block and brachial plexus block provides circumference anesthesia in the approximate location where an upper arm tourniquet is applied, thus its use for the management of tourniquet pain.⁹ The utility of the ICBN block in the management of post-operative management of persistent pain after breast cancer surgery and intercostobrachial neuralgia in breast cancer patients is still being investigated.^10,11

The ICBN block is routinely used as an adjunct to the brachial plexus nerve block to provide analgesic coverage for this tourniquet-induced pain of the upper extremity

Intercostobrachial Nerve Block Approaches

Several approaches have been described to block the ICBN. This nerve enters the axilla from the second intercostal nerve and traverses over the conjoint tendon of the latissimus dorsi and teres minor muscles before terminating in the subcutaneous tissue of the medial arm.^9,12 The conventional approach to blocking the ICBN is landmark-based and involves deposition of approximately 3-5 mL of local anesthetic (LA) subcutaneously in an anteroposterior trajectory 2-3 cm distal from the axillary crease.^9,12,13 An ultrasound-guided approach may follow a similar trajectory along the axilla as the conventional approach or may target the ICBN more proximally along the lateral chest wall deep to pectoralis minor.^4,6,13 Ultrasonography allows for visual confirmation of LA deposition superficial to the brachial fascia where the ICBN travels as the ICBN may be difficult to visualize.⁹ Magazzeni and colleagues conducted a randomized control trial comparing ultrasound-guided vs. conventional approaches to ICBN blocks. They found a greater incidence of complete success with the ultrasound-guided approach compared to the conventional technique, 88% and 19%, respectively.¹³

Necessity of ICBN in Upper Extremity Tourniquet Pain Management

The question then becomes, if an ICBN block does not adequately cover ischemic pain, should this block be performed to manage tourniquet pain during upper extremity surgery? A review of the literature demonstrated mixed results. There is a benefit in reducing pain scores and delayed onset of tourniquet pain when used with an axillary brachial plexus block in cases lasting at least 90 minutes.⁹ However, Le-Wendling et al. found that tourniquet pain can easily be managed with minimal amounts of systemic analgesia or sedation in the setting of a dense supraclavicular brachial plexus block and correct application of the tourniquet (avoiding skin folding and areas of shear stress under the tourniquet).⁴ Sebastian et al. arrived at a similar conclusion in the setting of a multiple-injection axillary brachial plexus block for upper extremity surgery.^.14 In addition, there is heterogeneity in the anatomic course of the intercostobrachial nerve, possibly leading to ineffective blockade in some cases,¹⁵ and blockade is subject to the challenge of difficulty in identifying the nerve due to its small size. Current landmark and ultrasound techniques may be insufficient to deliver the high-fidelity outcomes we expect from ultrasound-guided approaches elsewhere, such as the brachial plexus. There is a paucity of data in the literature regarding the impact of an ICBN block on clinical outcomes, such as the degree of increased sedation levels required, opiate analgesia requirements perioperatively, patient satisfaction, or overall patient experience.

Summary

In summary, the routine use of ICBN block to alleviate tourniquet pain during upper extremity surgery lacks strong evidence and is unnecessary. Additionally, evidence suggests that tourniquet pain may be comfortably managed with small supplemental amounts of systemic intravenous analgesia or sedation and proper padding beneath the tourniquet. Although in our practice we routinely perform ICBN block to supplement brachial plexus block for upper extremity surgeries, this practice needs to be questioned given the lack of evidence for benefit while subjecting the patient to a second needle puncture, discomfort, and risks such as vascular puncture, nerve injury, and local anesthetic systemic toxicity.

References

1. Fuselier CO, Binning T, Dobbs BM, et al. A study of the use of a double tourniquet technique to obtain hemostasis in combination with local standby sedation during podiatric surgery. J Foot Surg 1988;27(6):515-27.
2. Masri BA, Eisen A, Duncan CP, et al. Tourniquet-induced nerve compression injuries are caused by high pressure levels and gradients – a review of the evidence to guide safe surgical, pre-hospital and blood flow restriction usage. BMC Biomed Eng 2020;2:7. https://doi.org/10.1186/s42490-020-00041-5
3. Neal JM, Gerancher JC, Hebl JR, et al. Upper extremity regional anesthesia essentials of our current understanding, 2008. Reg Anes Pain Med 2009;34:134-70. https://doi.org/10.1097/aap.0b013e31819624eb
4. Le-Wendling L, Ihnatsenka B, Jones A, et al. Role of an intercostobrachial nerve block in alleviating tourniquet pain: a randomized clinical trial. Cureus 2022;14:e22196. https://doi.org/10.7759/cureus.22196
5. Wahal C, Grant SA, Gadsden J, et al. Femoral artery block (FAB) attenuates thigh tourniquet-induced hypertension: a prospective randomized, double-blind, placebo-controlled trial. Reg Anes Pain Med 2021;46:228-32. https://doi.org/10.1136/rapm-2020-102113
6. Quek KH, Low EY, Tan YR, et al. Adding a PECS II block for proximal arm arteriovenous access – a randomised study. Acta Anaesthesiol Scand 2018;62(5):677-86. https://doi.org/10.1111/aas.13073
7. Sariguney D, Mahli A, Coskun D. The extent of blockade following axillary and infraclavicular approaches of brachial plexus block in uremic patients. J Clin Med Res 2012;4(1):26-32. https://doi.org/10.4021/jocmr723w
8. Varela VM, Ruiz CA, Montecinos S, et al. Ultrasound-guided selective block of the medial brachial cutaneous and the intercostobrachial nerves for proximal arteriovenous fistula surgery. Reg Anesth Pain Med 2019;44:814–5. https://doi.org/10.1136/rapm-2018-100298
9. Seyed Siamdoust SA, Zaman B, Noorizad S, et al. Comparison of the effect of intercostobrachial nerve block with and without ultrasound guidance on tourniquet pain after axillary block of brachial plexus: a randomized clinical trial. Anesth Pain Med 2023;13(2):e134819. https://doi.org/10.5812/aapm-134819
10. Wijayasinghe N, Duriaud HM, Kehlet H, et al. Ultrasound guided intercostobrachial nerve blockade in patients with persistent pain after breast cancer surgery: a pilot study. Pain Physician 2016;19:E309–18.
11. Wisotzky EM, Saini V, Kao C. Ultrasound-guided intercostobrachial nerve block for intercostobrachial neuralgia in breast cancer patients: a case series. PM R 2016;8:273–7. https://doi.org/10.1016/j.pmrj.2015.10.003
12. Farag E, Mounir-Soliman L. Brown’s Atlas of Regional Anesthesia 7th ed. Philadelphia, PA: Elsevier; 2025:63-7, 263.
13. Magazzeni P, Jochum D, Iohom G, et al. Ultrasound-guided selective versus conventional block of the medial brachial cutaneous and the intercostobrachial nerves. Reg Anes Pain Med 2018;43:832-7. https://doi.org/10.1097/aap.0000000000000823
14. Sebastian M, Etxebarria A, Perez P, et al. Tourniquet pain after ultrasound-guided axillary blockade. J Anes & Inten Crit Med 2017;3:1-7. http://doi.org/10.19080/JAICM.2017.03.555624
15. Samerchua A, Leurcharusmee P, Panjasawatwong K, et al. Cadaveric study identifying clinical sonoanatomy for proximal and distal approaches of ultrasound-guided intercostobrachial nerve block. Reg Anes Pain Med 2020;45:853-9. https://doi.org/10.1136/rapm-2020-101783