What is the role of intercostal nerve blocks in pain management?

Updated: Jun 19, 2018
  • Author: Anthony H Wheeler, MD; Chief Editor: Meda Raghavendra (Raghu), MD  more...
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Intercostal nerve block is a useful procedure for defining potential source of pain in the chest and abdominal wall. Intracostal neural blockade at the posterior axillary line relieves pain of somatic origin but does not relieve pain arising in the thoracic or abdominal viscera, which are supplied by nociceptive fibers that follow sympathetic pathways located near the vertebral column. Intercostal nerve blocks can also offer relief of severe posttraumatic, postoperative, or postinfectious pain in the thoracic or abdominal wall.

Other indications include severe pain involving rib fractures or dislocation of the costochondral joints at the sternum, chest pain associated with pleurisy, pain associated with herpes zoster or intracostal nerve entrapment in the abdominis rectus sheath, and postoperative pain from thoracotomy, sternotomy, and after renal surgery through flank incisions. Caution should be used when performing bilateral intracostal blocks because ventilation may be impaired. The intercostal nerves are the ventral rami of T1-T11; however, the twelfth ventral ramus becomes the subcostal nerve and travels between the transversus abdominis and internal oblique muscles of the abdomen. See the image below.

Anatomy of intercostal nerves (cross-sectional vie Anatomy of intercostal nerves (cross-sectional view).

The intracostal nerve provides preganglionic sympathetic fibers to the sympathetic chain via the white rami communicantes and receives postganglionic neurons from the sympathetic chain through the gray rami communicantes. These gray rami join the spinal nerves near their exit from the intervertebral foramina.

A short distance beyond the intervertebral foramina, the nerve root divides into the posterior and anterior primary divisions. The posterior primary division carries sensory and motor fibers to posterior cutaneous and muscular tissues, which are paravertebral. The primary anterior division that becomes the intercostal nerve gives rise to the lateral cutaneous branch just anterior to the midaxillary line, which sends subcutaneous fibers anteriorly and posteriorly. The intercostal nerve continues to the anterior trunk where it terminates as the anterior cutaneous branch.

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