Overview
The thoracic spine is located in the middle back and is the longest region of the spine. It is a complex entity of interconnecting bones (vertebrae), joints, nerves, ligaments, and muscles all working together to provide support and stability. Injury to any of these structures in the thoracic spine can lead to upper back pain. A lot of times the pain is triggered by more than one structure, making the source difficult to identify. Chronic upper back pain is a chronic pain syndrome in the thoracic region lasting for at least 3 months. Upper back pain is most commonly caused by muscle irritation, also referred to as myofascial pain.
Anatomy (Thoracic Spine)
The thoracic spine consists of twelve vertebrae, labelled from T1 down to T12. The T stands for thoracic. The T1, the top thoracic vertebra, connects with the lowest cervical vertebra, C7, in the cervical spine above. The T12, the lowest thoracic vertebra, connects with the first lumbar vertebra, L1, in the lumbar spine below. Additionally, these vertebrae serve as attachment points for the ribcage. The thoracic spine performs several crucial roles, including:
1. Protecting the spinal cord and spinal nerves.
The thoracic vertebrae protect the spinal cord, a bundle of nerves that sends electrical signals throughout the body. The spinal cord travels through a large central canal or passage, called the spinal canal, and relays messages from the brain to the rest of the body. Openings or holes to each side of the canal, called the neural foramen (intervertebral foramen – foramen between the two adjacent vertebrae) provide pathways for the thoracic nerve roots. The thoracic spinal nerves control motor and sensory signals mostly for the upper back, chest, and abdomen.
2. Anchor for the rib cage.
The rib cage, supported by the thoracic spine in the back, forms a bony structure to surround and protect internal organs, such as the lungs and the heart.
Anatomy (The Costovertebral Joints)
These joints are where a thoracic vertebra connects or articulates with a rib.
Anatomy (Intervertebral Discs)
The intervertebral discs are shock absorbers that are located between the bones of the spine, called vertebrae (hence the name intervertebral). They are designed to help the back stay flexible while resisting forces and to allow bending, flexion and twisting of the spine. Each disc has a thick outer layer, known as annulus fibrosus, that surrounds the soft gel-like center, known as nucleus pulposus. A herniated disc occurs when the jelly-like material inside the disc nucleus herniates or leaks out of the disc, and presses on an adjacent nerve root.
Anatomy (Facet Joints)
The facet joints or zygapophyseal joints are a set of joints between the articular processes of two adjacent vertebrae. They are covered with cartilage and are surrounded by a lubricating capsule that enables the vertebrae to bend and twist. Each capsule has a rich supply of tiny nociceptive nerve fibers and implicates this structure as a potential source of pain. Similar to other joints in the body, the facet joints are vulnerable to inflammation and degeneration.
Causes
Upper back pain is caused due to an underlying bone, joint, disc, muscle, or nerve disorder in the middle back. The anatomical structures within the thoracic region are interconnected, so an injury to one is likely to affect the health of the others. In comparison to the cervical and lumbar spine, the thoracic spine is considerably resistant to injury and pain.
Causes (Muscle Strain and Ligament Sprain)
Strains or sprains in the middle back caused by damage to the muscles and ligaments are the most common sources of upper back pain. Strains occur when a muscle is stretched too far and tears, damaging the muscle itself. Sprains occur when over-stretching and tearing affects ligaments, which hold the bones together. A muscle strain and/or ligament sprain in the thoracic region can happen suddenly such as by lifting a heavy object, or by twisting the spine while lifting. It can also develop slowly over time from repetitive movements such as poor posture. Overuse or disuse of the large upper back muscles may result in muscle fatigue or weakness leading to upper back pain and discomfort. Myofascial pain refers to pain caused by muscular irritation. Trigger points are sensitive knots that can form in muscles.
Causes (Degenerative Disc Disease)
Another common cause of upper back pain is a degenerative disc disease. Degenerative disc disease is an age-related condition that happens when one or more of the discs deteriorate or break down, allowing vertebral bones above and below the disc to shift out of position. The bones can touch, pinching nearby nerve roots, leading to pain and possibly accompanying neurological symptoms such as pins-and-needles tingling, numbness, and/or weakness in the areas served by the affected thoracic nerve roots.
Causes (Thoracic Herniated Disc)
Thoracic disc herniation is a disease affecting the middle back region that may trigger upper back pain. A herniated disc can allow disc material to press harmfully against nearby nerve roots, triggering upper back pain and possibly pain and nerve symptoms such as tingling, numbness, and/or weakness that can radiate into the chest or abdomen. Generally, the thoracic spine is much less likely affected than the cervical and lumbar spine.
Causes (Facet Joint Disease)
Facet joint syndrome or facet joint disease is a pain arising from the intervertebral joint facets. It occurs when these joints become stressed and damaged. This damage can occur from everyday wear and tear, injury to the middle back or because of intervertebral disc degeneration and loss of inherent structural integrity. The cartilage that covers the stressed facet joints gradually wears away. The joints become swollen and stiff. The vertebral bones rub directly against each other, which can lead to growth of bone spurs along the edges of the facet joints and to an enlargement of the joints.
Causes (Thoracic Osteoarthritis)
Osteoarthritis of the spine develops as a consequence of the natural aging process. It can affect the spine at any level, resulting in pain and discomfort that can grow worse over time.
Thoracic spondylosis is a broad term used to describe pain from degenerative conditions of the thoracic spine.
Causes (Thoracic Foraminal Stenosis)
When a foramen (bony opening where a nerve root exits the spinal canal) narrows and becomes smaller, the nerve root has less space and may become impinged.
Degenerative changes related to thoracic osteoarthritis and/or thoracic degenerative disc disease may result in nearby bone spurs (osteophytes), thickening ligaments, or a disc bulging that creates harmful pressure against the nerve root in the foramen.
Causes (Thoracic Spinal Stenosis)
Spinal stenosis is an abnormal narrowing of the spinal canal (bone channel occupied by the spinal nerves or the spinal cord) or of the neural foramen (bony opening where a nerve root exits the spinal canal). This can cause a compression of the nerves or a compression on the spinal cord, known as thoracic myelopathy. Spinal stenosis is often the result of degenerative conditions such as osteoarthritis and/or degenerative disc disease.
Causes (Thoracic Radiculopathy)
Thoracic radiculopathy is a disease involving dysfunction of one or more nerve roots in the thoracic spine that typically manifests as pain radiating from the thoracic region into the distribution of the affected nerve root. It can be accompanied by sensory, motor, or reflex disturbances. Any condition that somehow compresses or irritates a thoracic nerve root can cause thoracic radiculopathy. It most often results from degenerative disease in the thoracic spine, but it can also occur due to an acute injury or illness.
Causes (Trauma)
Upper back pain can be caused by direct trauma to the middle back. This could be anything from a fall to a car accident or even a sports injury. High-energy impacts could cause a vertebra or rib to fracture or become displaced.
Cause (Compression fractures)
Compression fractures are most commonly caused by osteoporosis in elderly, especially in women. Osteoporosis is the loss of bone density resulting in bones that are brittle and liable to fracture. Compression of these vulnerable vertebra leads to small fractures at the front of the vertebral bone and consequently to bone deformation acquiring a wedge shape. Moreover, bone compression results in height loss of the osteoporotic vertebra, which can cause upper back pain and postural changes.
Causes (Kyphosis)
Kyphosis is the general term used to define any excessive forward curvature of the thoracic spine, causing hunching of the back. Several different causes can lead to this spine deformity.
The most common cause of kyphosis in elderly is a compression fracture due to osteoporosis. Kyphosis can also be developed as a result of degenerative disc disease. Scheuemann’s Kyphosis is a disease of adolescents due to abnormal growth of the spine and discs.
Common Causes (Scoliosis)
Scoliosis is the abnormal side-to-side curvature of the spine. This spine deformity mostly develops in middle childhood. In children, deformity is usually the only symptom. Upper back pain can be caused in adults with long-standing deformity and generally in severe cases of scoliosis.
Symptoms
Depending on the pain generator, symptoms can be experienced in a variety of ways. Upper back pain can be mild or so intense that the individual cannot follow everyday activities. It can occur suddenly or develop slowly and gradually aggravate over time.
Upper back pain symptoms might be short-lived, come and go regularly, return intermittently or become constant.
Upper back pain is commonly associated with stiffness, which is typically characterized by soreness and aching in muscles. Upper back pain symptoms may be aggravated by certain activities or postures and is often relieved by changing positions.
In cases of compression fracture due to osteoporosis, the first symptom is mostly a severe acute back pain which is often relieved by rest. The area around the fracture might be tender to the touch.
In cases of spinal stenosis and thoracic herniated disc, an affected spinal nerve in the thoracic region may result in upper back pain and possibly pain and nerve symptoms such as tingling, numbness, and/or weakness that can radiate into the chest or abdomen.
Treatment
Treatment options for upper back pain depend on the source of pain and severity of the injury.
Treatment for upper back pain focuses on minimizing pain, stabilizing the spine, and improving or maintaining mobility. It may include rest, heat therapy, analgesic/anti-inflammatory medications, muscle relaxants, manual and physical therapy.
Painful tense muscles can be relieved by combining the above treatments with infiltration of these muscles with a local anesthetic (trigger point infiltration).
Facet joint infiltrations or facet joint blocks may be administered not only to diagnose facet joint pain but also to treat it. If the patient shows a positive response to the facet joint blocks after having failed nonoperative care, the next treatment option is often radiofrequency denervation or rhizotomy.
In cases of compression fracture due to osteoporosis, the treatment involves both treatment of the fracture and treatment of the underlying osteoporosis. The treatment may include rest, heat therapy, analgesic/anti-inflammatory medications, physical therapy and back support. Surgery such as vertebroplasty and kyphoplasty may also be advisable.
The thoracic radiculopathy can usually be treated successfully without surgery with a combination of pain management techniques, physical therapy and therapeutic spinal injections.
Surgery may be recommended if the conservative therapies do not alleviate pain or if a significant neurological deficit such as progressive muscle weakness or compression on the thoracic spinal cord, known as thoracic myelopathy, exists.
References
- Kraemer J., Hasenbring M., Kraemer R., Taub E., Theodoridis T., Wilke H.J.: Intervertebral Disc Diseases: Causes, Diagnosis, Treatment and Prophylaxis. Thieme 2009.
- Theodoridis T., Kraemer J.: Injektionstherapie an der Wirbelsäule. Manual und Atlas. 3. Auflage. Thieme 2017.
- Niethard F., Pfeil J., Biberhaler P.: Orthopädie und Unfallchirurgie. 6. Auflage. Thieme 2009.
- Wirth CJ., Mutscher W.: Praxis der Orthopädie und Unfallchirurgie. 2. Auflage. Thieme 2009.
