Pinched intercostal nerve

A pinched nerve occurs when it is subjected to prolonged compression by surrounding structures: bones, cartilage or soft tissues. And pinched intercostal nerve - with disruption of its functioning and the appearance of various symptoms - refers to lesions of individual nerves, nerve roots and plexuses, which have the code G50-G59 according to ICD-10.

Causes of the intercostal nerve entrapment

In humans, there are 11 pairs of intercostal nerves (Nervi intercostales), which are anterior branches of the first 11 thoracic spinal nerves and run laterally behind the sympathetic trunk, entering the intercostal space (Spatium intercostale) - between the parietal pleura and the intercostal membrane.

Myotomes of the upper intercostal nerves (I-VI) include the nearby intercostal muscles and the transverse chest muscle, and the lower ones (VII-XI) innervate the corresponding intercostal muscles, and then, moving into the abdominal wall, provide innervation of the abdominal muscles (rectus, transverse, and oblique). In addition, these nerves are involved in innervation of the diaphragm and the extrapulmonary sheet of pleura, and their cutaneous branches connect the receptors of the skin of the anterior and lateral surfaces of the chest and abdomen with the CNS. [1]

The most likely causes of these nerves being pinched and irritated are related:

• with chest contusions and rib fractures;
• scar tissue formation after thoracotomy (chest surgery) or thoracoabdominal surgery. And also with the formation of a neuroma at the site of the postoperative scar, which takes over a section of the nerve and compresses it with fibrous tissue.

Pinching can result from kyphosis of the thoracic spine or the formation of tumors of the lungs and mediastinum.

Due to weakening of the fibrous connection and increased mobility of the adjacent cartilages of the VIII-XI ribs, they may shift relative to each other, which causes impingement and alteration of the intercostal nerve with the development of painful rib syndrome (or sliding rib syndrome). [2]

Create conditions for pinching and compression of the intercostal nerves and their cutaneous branches such skeletal anomalies as synostosis (fusion) of the ribs, as well as defects in bone and neurovascular structures.

Pinched intercostal nerve in pregnancy (at the end of the second and third trimester) occurs due to the displacement of the diaphragm and all overlying anatomical structures of the thorax by the enlarging uterus, as well as a strong stretching of the abdominal muscles.

Risk factors

Specialists call such risk factors for pinched intercostal nerve as:

• chest trauma;
• thoracic and abdominal surgery;
• curvature of the spinal column;
• Musculoskeletal diseases, especially in the elderly;
• connective tissue pathologies, primarily of autoimmune etiology;
• Lung and mediastinal neoplasms (benign and malignant).

For women, the risk of pinching (in addition to all of the above factors) is associated with the period of carrying a child, as well as breast lift and breast augmentation surgeries. [3]

Pathogenesis

The intercostal nerves are part of the somatic nervous system, and the response to nerve fiber irritation is neuralgic pain. Its pathogenesis is discussed in detail in the publication - Neuropathic pain. [4]

And the mechanism of pinching itself can be illustrated by the example of the development of chronic neuropathic pain syndrome of the abdominal wall, caused by pinching of cutaneous branches of VI-XI intercostal and XII subcostal nerves, which innervate the abdominal wall.

As part of the neurovascular bundle, they pass ventrally and caudally through the fibrous tunnels between the internal oblique and transverse abdominal muscles and pass at an angle into the rectus abdominis (Musculus rectus abdominis) - with a turn along its lateral border. This is where nerve compression can occur. In abdominal wall pain syndrome, there is severe pain, which patients perceive as pain of the internal organs of the abdominal cavity, i.e. Visceral pain. [5]

Neuropathologists explain the latter by the fact that nerve compression pain and visceral pain are mediated by different nociceptors, but sympathetic and somatic afferent fibers from the receptors go to the same dorsal horn of the spinal cord. [6]

See also - Neurogenic abdominal pain

Symptoms of the intercostal nerve entrapment

The first signs of intercostal nerve entrapment are manifested by pain between the ribs (along the intercostal spaces), which may be attack-like - burning, sharp, shooting - and becomes stronger with deep breathing, coughing, sneezing and any body movement involving the chest. The pain may radiate to the heart and scapula region, leading to speculation that it is cardiac in nature, although in reality it is nothing more than intercostal neuralgia.

Neuralgic symptoms such as a sensation of squeezing in the chest, tingling, numbness, burning, skin discoloration limited to the trigger zone, involuntary muscle twitching are also observed.

In cases of chronic neuropathic pain syndrome of the abdominal wall, intense sharp pain is concentrated in the abdominal region (in half of patients - in the right lower quadrant), forcing the patient to take antalgic posture to reduce pain; there is localized hyperesthesia (hypersensitivity) of the skin over the affected cutaneous branch of the intercostal nerve.

Complications and consequences

Neuralgic pain with pinched intercostal nerves can give consequences and complications in the form of loss of appetite, worsening of night sleep (up to insomnia), anxiety and depression.

In severe cases, neurologists do not exclude the threat of atrophic processes in the muscles, and due to damage to nerve fibers - paralysis.

Diagnostics of the intercostal nerve entrapment

In case of intercostal nerve entrapment, diagnosis includes history taking and physical examination with palpation of the affected areas. If the neurological origin of chronic pain in the abdominal wall is suspected, which develops when the cutaneous branches of the VI-XI intercostal nerves are pinched, palpation of the abdomen with relaxed and tense abdominal wall (Carnett's test) and diagnostic injection of anesthetic (1% lidocaine) below the lumbothoracic fascia are performed. [7]

Instrumental diagnosis is accomplished by:

• chest x-ray;
• chest CT scan, and if necessary, MRI;
• Nerve ultrasound;
• electrocardiography (to exclude cardiologic etiology of pain syndrome).

Differential diagnosis

In addition to angina pectoris, pericarditis, acute coronary syndrome, differential diagnosis should exclude the presence of pleurisy, pleuropneumonia, pulmonary embolism, fibromyalgia or myofascial pain syndrome, ladder muscle syndrome, costochondritis, pancreatitis, psychogenic abdominal pain, etc. In patients. [8]

Treatment of the intercostal nerve entrapment

Symptomatic treatment should be aimed at relieving pain, read more:

• Treatment of neuropathic pain
• Treatment of intercostal neuralgia

Orally taken medications: groups of non-steroidal anti-inflammatory drugs (Ibuprofen, etc.); anticonvulsants belonging to the group of anticovulsants - Carbamazepine (Zeptol), Gabapentin (Neuralgin), Pregabalin; analeptics - Imipramine (Deprinol) in low doses. Read more in the publication - Neuralgia tablets [9]

Externally, distraction agents (menthol or pepper patch and ointments containing capsaicin), analgesic ointments (5% lidocaine ointment, etc.), and variously formulated pain creams are used.

Subfascial injection intercostal nerve block with local anesthetic is performed. [10]

Physiotherapy treatment with electroanalgesia, drug phonophoresis, galvanotherapy, pulsed magnetotherapy, etc. Helps to relieve pain. More information in the article - Physiotherapy for neuritis and neuralgia of peripheral nerves.

Electropuncture and acupuncture and acupuncture. [11]

In severe cases - if the level of pain reduction with the above methods is insufficient - chemical neurolysis or neurectomy is used. Read more - Surgical methods of pain treatment.

If the symptoms of pinched intercostal nerve may help folk treatment in the form of rubbing the painful area with camphor alcohol, alcohol tincture of lilac leaves, comfrey roots, juice of ginger root or black radish, warming bags with hot salt, etc. [12]

Prevention

Assuming that prevention of intercostal nerve entrapment should be based on clinically based guidelines, the lack of such guidelines is noteworthy.

And preventing pain syndrome means eliminating its cause. However, it is important to know that physical activity increases sensitivity to pain. Therefore, physical activity should be moderate and brief.

Forecast

Without proper diagnosis and appropriate treatment, this syndrome has a disappointing prognosis: the quality of life is significantly reduced, and in some cases, functional disability occurs.

It is only in pregnant women that intercostal neuralgia associated with pinched intercostal nerve stops after delivery.