Intercostal neuralgia refers to a neuropathic condition involving the intercostal nerves, resulting in chest wall pain. The condition may respond to anti neuropathic medications though in some cases injection treatments may be needed. The intercostal nerves can be targeted under ultrasound guidance and pulsed radiofrequency ablation may be considered in patients who fail to make progress with conservative management.
The mechanism of neural injury may be due to ectopic signals from neural ‘sprouts’ after axonal injury. This new nerve growth may become a pain generator, especially if it becomes entrapped in scar tissue, forming a neuroma. Another mechanism may be compression or disruption of the nervi nervorum afferents in the connective tissue covering, producing a peripheral neuropathic pain.
Intercostal neuralgia can result from any condition that irritates or damages the intercostal nerve directly or indirectly:
Chest pain is the cardinal symptom. Because intercostal neuralgia involves a peripheral nerve, the pain is neuropathic rather than nociceptive. Pain is oftenunrelenting, shooting, burning, and deep. Patients may describe dysesthesias, paroxysmal pain and allodynia. Patients may use terms such as aching, cramping,pressure and heat to describe a dysesthetic pain.
Intercostal neuralgia pain is unilateral. It is common (up to 81%) after thoracotomy for coronary artery bypass grafting to the internal thoracic artery as well as after thoracotomy for tumor excision. During thoracotomy (either open or video-assisted thoracoscopic surgery), the intercostal nerve may be directly injured during rib resection, compressed by a retractor, or later entrapped by a healing rib fracture. Intercostal neuralgia may follow other forms of chest trauma. It may mimic the pain of shingles (herpes zoster) but without the rash and can occur without significant trauma in the elderly.
The aim of physical examination in intercostal neuralgia is to exclude other sources of pain. It is important to exclude cardiac and other visceral sources of chest pain. Although point tenderness is uncommon during myocardial infarction, the presence of point tenderness does not exclude significant cardiac disease. In intercostal neuralgia, there are no constitutional signs, such as fever, dyspnea, diaphoresis, or shortness of breath. Cardiopulmonary examination should be normal or stable if prior cardiovascular or pulmonary disease exists.
Careful palpation along the thoracotomy scar or rib may reveal a neuroma with the presence of a Tinel sign. Larger neuromas can often be visualized on magnetic resonance imaging or ultrasound.
Examination of the thoracic spine reveals full active range of motion without tenderness. In contrast, thoracic radiculopathy may be accompanied by pain with range of motion and at times thoracic spinal tenderness. Still, pain from thoracic radiculopathy is similar in quality and distribution to intercostal neuralgia. Active denervation potentials in the paraspinal muscles at the affected site confirm a radicular rather than a peripheral (intercostal nerve) source of the pain.
Intercostal neuralgia is often a diagnosis of exclusion. MRI scan may be helpful in excluding causes of thoracic radiculopathy including thoracic disc herniation and vertebral collapse. Appropriate oncologic workup, such as bone scans and laboratory investigations may be relevant in some patients, depending on risk factors and presentation findings.
Malignant neoplasm (primary or metastatic)
Vertebral compression fracture
Chest wall contusion
Referred pain from cardiac, pulmonary, vascular, or GI systems
Costovertebral or costochondral arthritis
Anti neuropathic drugs form the mainstay of management in intercostal neuralgia. These drugs include:
The injection can be of diagnostic value as well as therapeutic benefit. Intercostal nerve block involves injection of local anaesthetic and steroid around the intercostal nerve. The procedure is performed under real time ultrasound guidance to minimize the risk of pneumothorax.
In patients who get a positive response to diagnostic intercostal nerve block, pulsed radiofrequency ablation can offer sustained pain relief lasting several months. The procedure is performed under real time ultrasound guidance to minimize the risk of pneumothorax. Specialized equipment including radiofrequency machine, probe and RF needle is utilized to heat the intercostal nerve up to a temperature of 42°C.