Intercostal nerve blockade is a multi-level, regional technique that can provide analgesia or act as an anesthetic adjunct in various situations. Indications for an intercostal nerve block include costochondritis, incisional pain from thoracic surgery, breast surgery, rib fractures, and post-herpetic neuralgia (1). Additionally, utilization of this technique can reduce postoperative opioid consumption. Intercostal nerve block is generally well-tolerated and has a low complication rate, particularly when performed under ultrasound guidance (2).
The intercostal nerves are the anterior rami (division) of the T1-T12 spinal nerves, which are mixed nerves that carry both sensory and motor fibers. Each intercostal nerve travels in a neurovascular bundle with an intercostal artery and vein, with the nerve running inferior to both blood vessels. This neurovascular bundle accounts for the high levels of local anesthetic uptake into the blood noted after intercostal nerve blocks. Near the midaxillary line, the intercostal nerve sends an offshoot called the lateral cutaneous branch laterally through the internal and external intercostal muscles where it then divides into a posterior and anterior branch. Together, these innervate the skin and subcutaneous tissue of the lateral trunk and upper abdomen. Additionally, just before the individual intercostal nerves terminate, they send another branch called the anterior cutaneous branch, which divides into a lateral and medial branch. These supply the skin and subcutaneous tissue of the anterior trunk and abdomen, including the skin over both the sternum and rectus abdominis (1).
Few surgical procedures can be performed with an intercostal block alone, and the application of these blocks in combination with other techniques has largely been supplanted by epidural anesthesia. However, in patients with contraindications to neuraxial blockade, these techniques can be used alone or in combination with other blocks and general anesthesia to provide excellent surgical conditions for intra-abdominal procedures. Although surgical applications are possible with intercostal nerve block, the majority of indications are for postoperative analgesia (3).
The major complication with intercostal blockade is pneumothorax (collapsed lung). The actual incidence, however, was found to be as low as 0.07% in data on a large number of blocks performed by anesthesiologists at all levels of training (3). If this rare complication occurs, treatment is usually limited to observation, administration of oxygen, or needle aspiration. Rarely, chest tube drainage is required. The risk of systemic local anesthetic toxicity is present with multiple intercostal blocks because of the large volumes and rapid systemic absorption of the solutions.
With that said, patients should be monitored and observed carefully during the block and for at least 20 to 30 minutes afterward. Patients with severe pulmonary disease who rely on their intercostal muscles for respiration can exhibit acute decompensation after bilateral intercostal blockade (3). Ultrasound guidance may decrease the chance of intravascular injection and pneumothorax. The individual ribs to be blocked should be marked out appropriately (1). The ultrasound probe is then placed in a sagittal plane about 4 cm lateral to the spinous process. The ribs are visualized as a shadow while the pleura and lung are visualized anterior to the intercostal space. The needle can then be inserted in or out of a plane to the transducer and advanced until the tip is just below the inferior border of the rib. After negative aspiration, 3 to 5 mL of local anesthetic is injected, and the pleura should be visualized being pushed away.
Intercostal nerve block is an important anesthetic and pain management technique. For patient safety, it is advisable to follow specific guidelines and protocols to conduct adequate regional anesthesia procedures. Maintaining continuous closed-loop communication between all healthcare team members regarding the need, technique, and potential management issues associated with the regional anesthetic technique is of the utmost importance (1).
References
- Baxter CS, Singh A, Ajib FA, Fitzgerald BM. Intercostal Nerve Block. In: StatPearls. Treasure Island (FL): StatPearls Publishing; July 31, 2023.
- Lopez-Rincon RM, Hendrix JM, Kumar V. Ultrasound-Guided Intercostal Nerve Block. In: StatPearls. Treasure Island (FL): StatPearls Publishing; July 19, 2023.
- Perttunen K, Nilsson E, Heinonen J, Hirvisalo EL, Salo JA, Kalso E. Extradural, paravertebral and intercostal nerve blocks for post-thoracotomy pain. Br J Anaesth. 1995;75(5):541-547. doi:10.1093/bja/75.5.541