Pinched intercostal nerve

A pinched nerve occurs when it is subjected to prolonged compression by surrounding structures: bones, cartilage, or soft tissues. And pinching of the intercostal nerve - with a violation 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 pinched intercostal nerve

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

The myotomes of the upper intercostal nerves (I-VI) include the nearby intercostal muscles and the transverse muscle of the chest, and the lower ones (VII-XI) innervate the corresponding intercostal muscles, and then, moving into the abdominal wall, provide innervation of the abdominal muscles (straight, transverse and oblique). In addition, these nerves are involved in the innervation of the diaphragm and the parietal pleura, and the skin branches extending from them connect the receptors of the skin of the anterior and lateral surfaces of the chest and abdomen with the central nervous system. [1]

The most likely causes of pinching of these nerves and their irritation are related to:

• with bruises of the chest and fractures of the ribs;
• with the formation of scar tissue after a thoracotomy (chest surgery) or thoracoabdominal surgery. And also with the formation of a postoperative scar of a neuroma at the site, which captures a section of the nerve and squeezes it with fibrous tissue.

Pinching may be due to  kyphosis of the thoracic spine  or the formation of tumors of the lungs and mediastinum.

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

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

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

Risk factors

Specialists call such risk factors for pinching the intercostal nerve as:

• chest trauma;
• surgical interventions on the chest and abdominal region;
• curvature of the spinal column;
• diseases of the musculoskeletal system, especially in old age;
• connective tissue pathology, primarily of autoimmune etiology;
• neoplasms of the lungs and mediastinum (benign and malignant).

For women, the risk of pinching (except for all of the above factors) is associated with the period of bearing a child, as well as operations to lift and increase the mammary glands. [3]

Pathogenesis

The intercostal nerves are part of the somatic nervous system, and the response to irritation of the nerve fibers 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 the skin branches of the VI-XI intercostal and XII hypochondral nerves that innervate the abdominal wall.

As part of the neurovascular bundle, they pass in the ventral-caudal direction through fibrous tunnels between the internal oblique and transverse abdominal muscles and at an angle pass into the rectus abdominis muscle (Musculus rectus abdominis) - with a turn along its lateral border. It is from this place that compression of the nerve can occur. With pain syndrome of the abdominal wall, severe pain is observed, which patients perceive as pain in the internal organs of the abdominal cavity, that is, visceral. [5]

The latter is explained by neuropathologists by the fact that pain during nerve compression 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 pinched intercostal nerve

The first signs of pinched intercostal nerves are pain between the ribs (along the intercostal spaces), which can be paroxysmal - burning, sharp, shooting - and becomes stronger with a deep breath, coughing, sneezing and any movement of the body involving the chest. The pain can radiate to the region of the heart and scapula, causing assumptions about its cardiological nature, although in reality it is nothing more than  intercostal neuralgia .

There are also such neuralgic symptoms as a feeling of squeezing in the chest, tingling, numbness, burning, discoloration of the skin, limited by the trigger zone, involuntary muscle twitching.

In cases of chronic neuropathic pain syndrome of the abdominal wall, intense sharp pain is concentrated in the abdomen (in half of the patients - in the right lower quadrant), forcing the patient to take an antalgic position 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 when the intercostal nerves are pinched can give consequences and complications in the form of loss of appetite, deterioration of night sleep (up to insomnia), anxiety and depression.

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

Diagnostics of the pinched intercostal nerve

When pinching the intercostal nerves, the diagnosis includes taking an anamnesis and a physical examination with palpation of the affected areas. If a neurological origin of chronic pain in the abdominal wall is suspected, which develops when the skin branches of the VI-XI intercostal nerves are pinched, palpation of the abdomen is performed with a relaxed and tense abdominal wall (Carnett test) and a diagnostic injection of an anesthetic (1% lidocaine) below the lumbar-thoracic fascia. [7]

Instrumental diagnostics is carried out using:

• chest x-ray;
• computed tomography of the chest , and if necessary, MRI;
• ultrasound of the nerves ;
• electrocardiography (to exclude the cardiological etiology of pain syndrome).

Differential diagnosis

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

Treatment of the pinched intercostal nerve

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

• Treatment of neuropathic pain
• Treatment of intercostal neuralgia

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

Externally, distractions are used (menthol or pepper patch and ointments containing capsaicin), painkillers ointments (5% lidocaine, etc.) and  pain creams of various composition .

A subfascial injection  blockade of the intercostal nerves is performed with a  local anesthetic. [10]

Pain relief is facilitated by physiotherapy with the use of electroanalgesia, drug phonophoresis, galvanotherapy, pulsed magnetotherapy, etc. More information in the article -  Physiotherapy for neuritis and neuralgia of peripheral nerves .

The analgesic effect is given by electropuncture and  acupuncture . [11]

In severe cases - with an insufficient level of pain reduction using the above methods - they resort to chemical neurolysis or neurectomy. Read more -  Surgical treatments for pain .

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

Prevention

If we assume that the prevention of pinched intercostal nerves should be based on clinically sound recommendations, then it should be noted that there are no such recommendations.

And the prevention of pain syndrome means the elimination of its cause. However, it is necessary to know that physical activity contributes to increased sensitivity to pain. Therefore, physical activity should be moderate and short.

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.

And only in pregnant women after childbirth does intercostal neuralgia associated with pinching of the intercostal nerve stop.