Pinched intercostal nerve

Pinching of any nerve occurs when it is subjected to prolonged compression by surrounding structures: bones, cartilage or soft tissues. And pinching of the 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 intercostal nerve entrapment

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

The myotomes of the upper intercostal nerves (I-VI) include the adjacent intercostal muscles and the transverse thoracic 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 participate in the innervation of the diaphragm and the parietal pleura, and the cutaneous 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 and irritation of these nerves are related to:

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

Pinching may be a consequence of 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 adjacent cartilages of the VIII-XI ribs, their displacement relative to each other is possible, which causes pinching and alteration of the intercostal nerve with the development of painful rib syndrome (or sliding rib syndrome). [ 2 ]

Skeletal anomalies such as synostosis (fusion) of the ribs, as well as defects in bone and vascular-nerve structures, create conditions for pinching and compression of the intercostal nerves and their cutaneous branches.

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

Risk factors

Experts name the following risk factors for intercostal nerve entrapment:

• chest injuries;
• surgical interventions on the chest and abdominal area;
• curvature of the spine;
• diseases of the musculoskeletal system, especially in old age;
• connective tissue pathologies, primarily of autoimmune etiology;
• neoplasms of the lungs and mediastinum (benign and malignant).

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

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 cutaneous branches of the VI-XI intercostal and XII subcostal nerves, which innervate the abdominal wall.

As part of the vascular-nerve 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 abdominal wall pain syndrome, severe pain is observed, which patients perceive as pain in the internal organs of the abdominal cavity, that is, visceral. [ 5 ]

Neurologists explain the latter by the fact that pain from 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 intercostal nerve entrapment

The first signs of intercostal nerve entrapment 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 body movement involving the chest. The pain can radiate to the heart and shoulder blade area, causing assumptions about its cardiological nature, although in reality it is nothing more than intercostal neuralgia.

Also observed are neuralgic symptoms such as a feeling of tightness in the chest, tingling, numbness, burning, skin discoloration limited to the trigger zone, and involuntary muscle twitching.

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

Complications and consequences

Neuralgic pain from pinched intercostal nerves can lead to consequences and complications in the form of loss of appetite, deterioration of night sleep (even insomnia), anxiety and depression.

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

Diagnostics intercostal nerve entrapment

In case of intercostal nerve entrapment, diagnostics include anamnesis collection and physical examination with palpation of the affected areas. If a neurological origin of chronic abdominal wall pain is suspected, which develops with entrapment of the cutaneous branches of the VI-XI intercostal nerves, palpation of the abdomen with a relaxed and tense abdominal wall (Carnett test) and a diagnostic injection of anesthetic (1% lidocaine) below the lumbothacral fascia are performed. [ 7 ]

Instrumental diagnostics is carried out using:

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

Differential diagnosis

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

Treatment intercostal nerve entrapment

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

• Treatment of neuropathic pain
• Treatment of intercostal neuralgia

Orally administered medications: non-steroidal anti-inflammatory drugs (Ibuprofen, etc.); anticonvulsants, belonging to the anticonvulsant group - Carbamazepine (Zeptol), Gabapentin (Neuralgin), Pregabalin; analeptics - Imipramine (Deprinol) in low doses. More details in the publication - Tablets for neuralgia [ 9 ]

Externally, distracting agents (menthol or pepper patches and capsaicin-containing ointments), pain-relieving ointments (5% lidocaine, etc.) and pain creams of various compositions are used.

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

Pain relief is facilitated by physiotherapy treatment using electroanalgesia, medicinal phonophoresis, galvanotherapy, pulsed magnetic therapy, etc. More information in the article - Physiotherapy for neuritis and neuralgia of peripheral nerves.

Electropuncture and acupuncture provide an analgesic effect. [ 11 ]

In severe cases – when the pain syndrome is not reduced sufficiently by the methods listed – chemical neurolysis or neurectomy is used. Read more – Surgical methods of pain treatment.

If the symptoms of intercostal nerve entrapment are mild, folk remedies can help, such as rubbing the painful area with camphor alcohol, alcohol tincture of lilac leaves, comfrey roots, ginger root or black radish juice; warming up with bags of hot salt, etc. [ 12 ]

Prevention

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

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 short-term.

Forecast

Without proper diagnosis and appropriate treatment, this syndrome has a disappointing prognosis: 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 pinched intercostal nerve stop.