Displacement, Thoracic Intervertebral Disc Without Myelopathy

Risk: Risk for thoracic disc protrusion is slightly greater in males and in females. Most thoracic disc herniations occur in individuals between the ages of 40 and 60 years old (Canale).

Incidence and Prevalence: Symptomatic herniated thoracic discs are rare, accounting for 0.25% to 0.75% of all symptomatic disc herniations; the population incidence is estimated at 1 per million (Chen). The incidence of asymptomatic thoracic disc abnormalities is much higher.

History: Important items to note in the history include: information about pain (onset, location, quantity, quality, setting, aggravating and alleviating factors, associated symptoms), axial vs. peripheral pain, and history of mid-back injury. Disc-related pain without nerve root involvement may be vague and diffuse. Radiating (radicular) pain can be dull and aching or sharp and electric; thoracic pain may be absent.

In the absence of a thoracic injury, thoracic disc displacement may be difficult to diagnose. Upper thoracic disc herniation (T2-T5) can be mistaken for cervical disc disease, while lower thoracic disc herniation can mimic lumbar disc disease. Individuals may complain of acute, chronic, or recurrent mid-back (axial) or rib pain. In some cases, the pain may begin abruptly after an injury such as a fall onto the buttocks or landing flat on the feet. Straining for a bowel movement, coughing, or sneezing may aggravate pain. Other symptoms may include muscle weakness (motor), sensory disturbances (e.g., touch), and bowel or bladder dysfunction (15% to 20% of patients (Canale). Radiating pain caused by pressure on spinal nerve roots (radicular pain) and sensory loss from nerve root compression follows the distribution of the affected intercostal nerve, which runs between the ribs from the back towards the front of the body at the level of the disc herniation.

Physical exam: Palpation of the affected vertebra may elicit tenderness. Range-of-motion of the entire spine, hips, knees, and ankles should be assessed as well as bilateral straight leg raising. Neurologic examination may reveal deficits such as decreased sensation along the course of a rib. The physician may assess abdominal reflexes, lower extremity reflexes, and sensation.

Tests: Laboratory testing can help to rule out other conditions. Blood tests may include erythrocyte sedimentation rate (ESR) to evaluate inflammation, a complete blood count (CBC) to look for infection or multiple myeloma, rheumatoid factor, and serum protein electrophoresis. Human leukocyte antigens (HLA-B27) may be typed.

X-rays of the thoracic spine may help to exclude tumor and infection. In addition, the x-ray may show congenital or developmental deformities of the spine such as side-to-side curvature (scoliosis) or a hunchback (kyphosis). Individuals who have such deformities are predisposed to thoracic disc degeneration. Thoracic discs may undergo calcification, which can be seen on CT.

MRI is considered the most useful and effective imaging test to confirm the diagnosis of thoracic disc herniation. The thoracic spine is slightly more difficult to image by injecting dye into the spinal canal followed by x-rays (myelography). Myelography is may be useful in conjunction with enhanced CT scans to evaluate the bony anatomy and assess calcification of a herniated thoracic disc.

Individuals who experience a displacement in one of the thoracic intervertebral discs may benefit from a short course of rehabilitation. As stated earlier, the thoracic area is not a common site for displacement of intervertebral disc.

Therapy protocol will focus on decreasing pain and regaining mobility and strength to that particular region of the spine. The therapy program will include instruction in a home exercise program with focus on postural alignment, proper body mechanics and trunk endurance and strength. Modalities such as moist heat or electric stimulation may be used to control pain in order to promote activity and progress with the exercise program.

The exercise program should combine coordination, aerobic conditioning and flexibility exercises (Danielsen). A short course of cognitive pain management may benefit individuals experiencing psychological distress or lack of improvement with treatment. An ergonomic evaluation with modifications may enable the individual to maintain or return to work and reduce the risk of re-injury. Vocational services should be available for individuals who cannot return to their previous job title or do not have a job to which to return.

Few cases will require surgical management (Brown; Gibson). For postoperative management see Discectomy.