A herniated disc in the thoracic spine, also known as a dorsal or thoracic herniation, occurs when the intervertebral discs between the thoracic vertebrae rupture or bulge, typically at the rear outer part. The disc provides movement between the vertebral bodies and acts as a suspension to carry weight. The outer part of the disc is called the annulus fibrosus, while the inner part is known as the nucleus pulposus. The outer layer is tougher and resistant to trauma, with its weakest point located at the rear, mid-lateral section—this is where most herniations occur due to tears.
Thoracic herniated discs are rare because the thoracic spine is encased by the rib cage and has more restricted movement compared to the cervical and lumbar regions. The thoracic or dorsal spine consists of 12 thoracic vertebrae. Herniated discs most commonly occur between T8-T12 vertebrae. Symptoms vary depending on the level and location of the compression:
- Band-like pain, numbness, and tingling radiating to one side of the torso.
- Pain in the middle of the back.
- Severe cases with large, calcified central herniations may include gait disturbance, back pain, loss of bladder or bowel control, and paralysis.
Diagnosis of Thoracic Herniated Discs
The gold standard for diagnosis is MRI and CT scans. A CT scan is essential for evaluating disc calcification.
Treatment of Thoracic Herniated Discs
The first choice in treatment is non-surgical methods, aiming to relieve the patient's pain and enable pain-free daily activities. These methods include physical therapy and injection treatments performed by Algology specialists. Non-surgical methods can be effective for up to six months in patients without neurological deficits. Surgery should be considered for cases involving significant muscle weakness, paralysis of the sphincter muscles controlling bladder and bowel function, or progressive muscle weakness. Surgery is also recommended for patients whose symptoms do not improve with non-surgical methods.
Surgical Approaches for Thoracic Herniated Discs
There are two main approaches to the surgical treatment of thoracic herniated discs: posterior-posterolateral and anterior. While lumbar herniations are typically approached entirely from the back, certain cases of thoracic herniation may require an anterior approach.
The posterior removal of calcified central herniations carries higher neurological risks compared to the anterior approach. Manipulating the spinal cord to the right or left to access the herniation can lead to severe neurological complications. Therefore, anterior approaches are safer. These can be performed using minimally invasive, thoracoscopic, or open thoracotomy methods. Minimally invasive or thoracoscopic approaches are particularly preferred in elderly patients.
For non-calcified central or paracentral herniations, posterior-posterolateral approaches can be performed under microscope guidance. Nerve conduction should be monitored using neuromonitoring techniques during surgery in both anterior and posterior approaches.