Thoracic Herniated Disc
In the human spine, there is a single intervertebral disc between the every vertebra except the first two at the top of the spine (Axis and Atlas). Discs are solid on the outside, and composed of a gelatinous inner material that provides a gel cushioning to absorb and disperse stress away from the spine as weight presses down on it. Weight and pressure are applied to our spines when we sit upright from a lying down position, when we are active on our feet, and when we lift heavy objects. Our discs are designed to be strong and durable, and to last for the lives our bodies. That being said, these discs do wear out over time, starting from a very young age.
Over time, these discs lose the volume of material inside their gel-like core. The discs also become frayed in their outer solid envelope, also known as the nucleus pulposus. Over time, these discs may shrink in height as they lose volume in their interior, related to their increasing inability to retain water. Over time, the outer wall of the discs becomes frayed and thin, sometimes to the point that they tear all the way through. When the outer wall of the disc completely tears to the point that its goopy core spills out of it, this condition is known as a herniated disc. A less severe form of this problem is known as a bulging disc, in which the wall swells outward due to its weakening, but does not rupture completely.
These disc herniations may occur in any disc of the spine, though they are more common in the cervical (neck) and lumbar (lower back) spine. The discs in these two sections of the spine are more vulnerable to injury for a couple of reasons. The discs and joints in the neck and lower back allo3w for much more movement, which gives us our ability to move freely, though it also makes these sensitive tissues more prone to injury. The disc and joints in the thoracic spine, however, allow for much less movement, due to its primary purpose of stabilizing the chest cavity and allowing us the ability to stand upright. For this reason, a thoracic herniated disc or degenerated disc is rarely the cause of upper back pain. It does happen sometimes, however, and often enough to warrant discussion here. Here's a look at some of the causes of thoracic disc herniations, how they are diagnosed, and how they are treated.
Thoracic Degenerative Disc Disease: The symptoms of disc herniations in the T-Spine will be associated with the level in which the herniation occurs and the amount of pressure being put on the spinal nerve root. Because the T-Spine has so many levels, the symptoms of thoracic degenerative disc disease may be very varied. Damage to these nerves associated with disc herniations may affect our upper body as well as the regulation of breathing.
When thoracic herniated discs do occur, it is usually in the bottom portion of the T-Spine - known as the thoracolumbar junction. The thoracolumbar junction is the vertebrae and associated structures between T8-T12. This region of the thoracic spine is sometimes described as the mid back. Unlike cervical and lumbar herniated discs, lesions to the discs of the thoracolumbar junction do not usually cause the type of pain and related neurologic symptoms (numbness, muscle atrophy) that would occur elsewhere. Because these disc herniations don't typically cause pain and radiculopathy, they rarely require spine surgery to fix them.
When do disc herniations in the thoracic spine actually cause upper back pain or mid back pain? One study indirectly focused on this topic. In one study, 90 people who experienced no back pain at all submitted themselves to MRI scans that imaged the thoracic spine. Here are some of the things that these researchers found.
None of these subjects reported upper back pain at the time that these radiographic images were taken. Researchers followed up with these patients periodically for the next 26 months. None of these subjects reported back pain at any time in this 24 months period.
- Their MRIs indicated spinal cord impingement in 29% of the pictures.
- 37% of MRIs indicated the presence of a thoracic herniated disc.
- 73% of subjects had either thoracic degenerative disc disease, a thoracic herniated disc, or other disc abnormalities in the upper back.