Excessive movement of the vertebral bodies relative to each other is considered spinal instability (ie, loss of functional integrity of the systems that provide stability). Some movement is certainly normal.
- Movement can be described as erratic when the movement is significantly greater than that of adjacent levels.
- Spinal instability may be the result of an injury degenerative process, tumor, previous surgery, or congenital disease.
- Symptoms of spinal instability may include neck or back pain, neuralgia, and muscle spasms .
- This usually occurs when a particular disc or facet joint degenerates to the point that it can no longer support body weight through that segment of the spine.
- Osteoarticular ligaments and myofascia are two systems in the chest that contribute to stability. In the mid-thorax, rotational instability involves the spine and ribs of the segment.   
Thoracic instability, if present, manifests as spondylolisthesis (anterior translation of the head vertebra over the tail vertebrae). Lateral tilting of the thoracic spine is rare and may be due to the constraints provided by the thorax and uncinate joints.
Degenerative thoracic spondylolisthesis is rare because the thoracic spine is naturally more stable in an anterior-to-posterior direction than the cervix or spine. This is due to the ribs and the coronal orientation of the facet joints.
Clinically Relevant Anatomy
To understand how these two mechanisms contribute to instability, it is important to understand the anatomy of the vertebral motion segment.
Each layer of the spine functions as a three-joint complex.
- There are two small joints at the back and a large disc at the front as a joint.
- This tripod offers exceptional stability, supports weight above every level, and provides support for movement in all directions.
- As long as the disc remains healthy, it can withstand these forces for many years without symptoms .
- The thoracic spine may become unstable when the posterior structures and bilateral costovertebral joints are disrupted.
Thoracic spine additional points
- The costovertebral joint is an important stabilizer of the thoracic motion segment.  
- The ribcage is fixed to the thoracic spine by the costovertebral joints.
- The thoracic spine is connected to adjacent vertebrae by bilateral costovertebral joints.
- The costovertebral joint and its surrounding ligaments such as the costotransverse process and the intra-articular ligaments connect the nearby vertebrae and ribs. 
- The stabilizing effect of the costovertebral joints of the thoracic spine and the ribcage is particularly pronounced during lateral bending and axial rotation.
This instability is called spondylolisthesis, which literally means one lumbar vertebra slips forward relative to the vertebrae below.
Spondylolisthesis can be caused by a variety of mechanisms. 2 main reasons
- Stress fractures in the vertebrae called spondylolysis
- Acquired degenerative changes in facet joints. 
Stress fractures occur through weak “parts” of the vertebrae and often break on both sides.
- A fracture can be the result of direct trauma, usually a concentrated strain from athletic activity or an inherited weakness in that area of the bone.
- Pars are thin sections of vertebrae that snap with repeated use; imagine a paper clip being bent repeatedly and eventually snapping. The most common partial stress fracture occurs during adolescence; it is estimated that as many as 5-7% of adolescents suffer ciliary body fractures.
- This is extremely common among high-intensity athletes and those exposed to rotational forces.
- Fortunately, these fractures usually heal with a period of rest and core strengthening.
- If the bone does not heal, fibrous scar tissue may form to provide support.
For many people, this fracture does not cause problems for decades. Over time, reduced posterior support causes more force to be exerted on the anterior disc, accelerating degenerative disc disease. When the disc narrows due to degeneration, the bones above and below the disc also move or Slip each other. The fracture gap thus widens, causing the vertebrae to move forward more. This movement indicates segmental spinal instability.
Degenerative Changes in the Facet Joints
Another major cause of spondylolisthesis is the acquired degeneration of the facet joints. As these joints degenerate, the small supporting ligaments wear down and become loose. These ligaments are vital for support. This laxity allows the facet joints to open up more or separate with movement. this The facet joints can be a source of pain and allow the disc to slide forward as the joints separate more than they should .
A complete medical history and physical examination are always the first part of the diagnostic workup for any pain condition.
- A spinal x-ray is usually obtained to assess for instability. Clients will flex and stretch for different x-rays to assess whether bones move abnormally as you change positions.
- Advanced imaging tests, such as CT scans or MRI scans, may also be ordered to get more information on the amount of nerve compression that may be caused by instability and to see if there are any fractures in the bone structure that could lead to instability sex .
- With minimal pain without any nerve impingement, treatment of spinal instability will aim at conservative measures. This may involve physical therapy with NSAIDs or pain relievers to strengthen the core muscles and possible activity modifications.
- Spinal injections may also be considered to help reduce discomfort if the instability causes severe pain or causes pain in the arms or legs.
- Surgery is often recommended if pain cannot be relieved by conservative treatment, or in cases where instability has caused significant compression of the spinal cord or spinal nerves. While the specifics of surgery are often individualized based on a given patient’s findings Surgical fusion is recommended. 
Physical Therapy Management
- For patients with suspected iatrogenic instability resulting from posterior foraminotomy, conservative management should be attempted and considered as first-line therapy. 
- The thoracic spine can be viewed as a hidden source of improved overall postural stability. Kinetic chains for therapy or training may be appropriate to focus on the chest area.   
- The multifidus and erector spinae help force the mid-thoracic region to close. Therefore, it is very important that these muscular problems be addressed during the rehabilitation of an unstable thorax. Regional dynamic stability, neutral zone controllable With proper training. [twenty three]
- Example Workout Program – 10 minute warm up 40 minute stabilization 10 minute cool down and stretching Exercise ball or proprioceptive balance and resistance training can be incorporated into the program if desired. Can increase movement speed According to the patient’s work and entertainment needs. The load should be applied bilaterally before working on one side. 
The program consists of:
- General exercises for the spine: use a steady pressure biofeedback device (ChattanoogaUSA) based on the contraction of the relevant muscular activity of the spinal segment. The training program is designed to create a neutral spine and activate the deep spine muscles.
- Specific exercises for the thoracic spine: Postural alignment and minimal multifidus activation and scapula orientation for the thoracic spine group. Participants were asked to hold as many positions and contractions as possible during the exercise and throughout the day.
- Abdominal bracing has also been shown to be one of the most effective muscle-building techniques, even compared to dynamic exercises involving trunk flexion/extension movements. Additionally, abdominal support should be included in an exercise program when the goal is to improve trunk stability. In addition, abdominal bracing has also been shown to increase spinal stiffness, promote spinal segmental stability, and is often recommended and/or included in rehabilitation. Further research is needed on its actual impact on spinal stability in rehabilitation.   . Also along Skoch Jesse et al. Further investigation is needed to determine when and if (postoperatively) bracing is used in surgically stabilized thoracolumbar fractures. Controlled studies should include careful analysis of pseudarthrosis and complication rates. 
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- Skoch, Jesse, et al. “Bracing after surgical stabilization of thoracolumbar fractures: a systematic review of evidence, indications, and practices.” World neurosurgery 93 (2016): 221-228.