Abstract
Thoracic radiculopathy results from nerve root malfunction at the thoracic spine. Several conditions can lead to thoracic radiculopathy, although disc dislocation leading to nerve root impingement is the most common. Most often asymptomatic, thoracic radiculopathy can lead to chest, midscapular, lower extremity, or abdominal pain, as well as lower limb weakness if myelopathy is also present. Physical examination in such patients can be unspecific, but should be thoroughly conducted together with a meticulous clinical history to rule out serious diseases. Imaging studies are often necessary. Magnetic resonance imaging is the imaging study of choice in these cases.
Treatment will depend on pain severity and functional limitation. It includes pain control medications, physical therapy, guided injections under fluoroscopic guidance, and surgery.
Definition
Thoracic radiculopathy is a painful syndrome caused by mechanical compression, chemical irritation, or metabolic abnormalities of a thoracic spinal nerve root. Thoracic disc herniations are estimated to occur in approximately 12% to 37% of the population and are more often asymptomatic. Its incidence is equal between men and women. It accounts for less than 2% of all spinal disc surgeries and 0.15% to 4% of all symptomatic spinal disc herniations. The majority of thoracic disc herniations (35%) occur between the levels of T8 and T12, with a peak (20%) at T11-T12. Most patients (90%) present clinically between the fourth and seventh decades of life; 33% present between the ages of 40 and 49 years. Approximately 33% of thoracic disc protrusions are lateral, preferentially encroaching on the spinal nerve root. The remainder are central or central lateral, resulting primarily in various degrees of spinal cord compression. Synovial cysts, although rare in the thoracic spine (0.06% of patients requiring decompressive surgery), may also be responsible for foraminal encroachment. These tend to be more common at the lower thoracic levels.
Natural degenerative forces and trauma are generally thought to be the most important factors in the etiology of mechanical thoracic radiculopathy. Foraminal stenosis from bone encroachment may also cause compression of the exiting nerve root and radicular symptoms.
The most common cause of thoracic radiculopathy is a metabolic condition: diabetes mellitus. It often results in multilevel disease. This may occur at any age but often appears with other neuropathic symptoms due to injury to the blood supply to the nerve root. Another etiology that should be considered a possible cause of thoracic radiculopathy is neoplastic compression. Primary spine tumors are rare, although the spine is a frequent metastasis site (4% to 15%) of primary solid tumors, such as breast, lung, and prostate cancer. Regarding spine metastasis, the thoracic spine is the most commonly affected (70%), followed by lumbar (20%) and cervical (10%). Finally, other less common causes that may lead to thoracic radiculopathy include scoliosis, inflammation induced by herpes zoster, and tuberculosis.
Symptoms
Most patients (67%) present with complaints of “band-like” chest pain ( Fig. 43.1 ). The second most common symptom (16%) is lower extremity pain. Injury to nerve roots T2-3 may be manifested as axillary or midscapular pain. Injury to nerve roots T7-T12 may be manifested as vague and poorly localized abdominal pain. Abdominal wall bulging due to weakness of local muscles may also suggest thoracic radiculopathy. Less common symptoms such as mastalgia can occur due to thoracic radiculopathy.
Unlike thoracic radiculopathy, spinal cord compression produces upper motor neuron signs and symptoms consistent with myelopathy. Therefore examiners should pay close attention to the presence of motor impairment, hyperreflexia and spasticity, sensory impairment, and bowel and bladder dysfunction. The last may be caused by T11-T12 lesions damaging the conus medullaris or cauda equina.
Thus in thoracic radiculopathy, pain—localized, axial, or radicular—is the primary complaint in 76% of patients. It is also important to include in the history any trauma (present in 37% of patients) or risk factors for non-neurologic causes of chest wall or abdominal pain. Thoracic compression fractures that may mimic the symptoms of thoracic radiculopathy may be seen in young people with acute trauma, particularly falls, regardless of whether they land on their feet. In older people (particularly women with a history of osteopenia or osteoporosis) or in individuals who have prolonged history of steroid use, a compression fracture should be considered. Because thoracic radiculopathy is not common, it is important in nontraumatic cases to be suspicious of more serious pathologic processes, such as infection or cancer. Therefore a history of weight loss, decreased appetite, immunosuppressive factors, fever, chills, or previous malignant disease should be elicited.
Physical Examination
The physical examination may show only limitations of range of motion—particularly trunk rotation, flexion, and extension—generally due to pain. In traumatic cases, location of ecchymosis or abrasions should be noted. Range of motion testing should not be done repeatedly if an acute spinal fracture is suspected. Careful palpation for tenderness over the thoracic spinous and transverse processes, as well as over the ribs and intercostal spaces, is critical in localizing the involved level. Pain with percussion over the vertebral bodies should alert the clinician to the possibility of a vertebral fracture.
On the other hand, uncommon symptoms in the lower limbs, such as pain, reflex changes, spasticity, and weakness, can be a result of spinal cord compression by thoracic disc herniation, although this phenomenon is seldom observed.
Physical examination in diagnosis of thoracic radiculopathy has a modest accuracy and reliability because there is difficulty in testing strength of possibly affected muscles (such as paraspinal, intercostal, and abdominal muscles) in isolation, although it is crucial for ruling out other possible causes of pain or neurologic abnormalities. In addition, sensation may be abnormal in a dermatomal pattern. This will direct the examiner to more closely evaluate the involved level. Any abnormalities of the spine should be noted, including scoliosis, which is best detected when the patient flexes forward. A thorough examination of the cardiopulmonary system, abdominal organs, and skin should be performed, particularly in individuals who have sustained trauma or relevant comorbidities.
Functional Limitations
The pain produced by thoracic radiculopathy often limits an individual’s movement and activity. Patients may be limited in activities such as dressing and bathing and other activities that include trunk movements, such as putting on shoes. Work activities may be restricted, such as lifting, climbing, and stooping. Even sedentary workers may be so uncomfortable that they are not able to perform their jobs. Anorexia may result from pain in the abdominal region.
Diagnostic Studies
Because of the low incidence of thoracic radiculopathy and the possibility of serious disease (e.g., tumor), the clinician should have a low threshold for ordering imaging studies in patients with persistent (more than 2 to 4 weeks) thoracic pain of unknown origin. Magnetic resonance imaging remains the imaging study of choice to evaluate the soft tissue structures of the thoracic spine. Computed tomography and computed tomographic myelography are alternatives if magnetic resonance imaging cannot be obtained.
The electromyographic evaluation of thoracic radiculopathy can be challenging because of the limited techniques available and the lack of easily accessible muscles representing a myotomal nerve root distribution. The muscles most commonly tested are the paraspinals, intercostals, and abdominals. The risk of pneumothorax is 8.8% when investigating intercostal nerve conduction, which discourages many practitioners from using the technique. The clinician must investigate multiple levels of the thoracic spine to best localize the lesion. Techniques for intercostal somatosensory evoked potentials have also been shown to isolate individual nerve root levels.
In patients who have sustained trauma, plain radiographs are advised as a primary approach to rule out fractures and spinal instability.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
