Syndesmophytes are abnormal bony growths that develop in the spine. They are essentially bone spurs that form within the ligaments and connective tissues of the vertebral column. Their presence can significantly impact spinal flexibility and overall mobility.
Understanding Syndesmophytes
Syndesmophytes refer to bony outgrowths that occur within the spinal ligaments or the annulus fibrosus, the outer ring of the intervertebral disc. This formation involves ossification, where soft tissues transform into bone. These growths appear in the spine, particularly in the thoracic (mid-back) and lumbar (lower back) regions.
They can bridge adjacent vertebrae, leading to a loss of spinal flexibility and mobility. Unlike typical osteophytes, which protrude perpendicularly from the bone, syndesmophytes grow vertically and parallel to the spine, eventually connecting vertebrae. This growth pattern can result in the spine becoming stiff and rigid.
Conditions Linked to Syndesmophytes
Syndesmophytes are strongly associated with specific inflammatory conditions, most notably Ankylosing Spondylitis (AS). They are considered a hallmark feature of this chronic inflammatory disease, which primarily affects the axial skeleton, including the spine and sacroiliac joints. The chronic inflammation in AS can lead to the formation of these bony bridges.
While AS is the most common cause, syndesmophytes can also appear in other inflammatory conditions known as spondyloarthropathies. These include psoriatic arthritis, a form of arthritis that affects some people with psoriasis, and reactive arthritis, which can develop after an infection elsewhere in the body. In AS, syndesmophytes tend to be thinner, symmetrical, and involve the anterior and lateral vertebral body margins. In contrast, those seen in psoriatic arthritis and reactive arthritis may be larger, more irregular, and often asymmetrical.
The underlying mechanism involves chronic inflammation at the sites where ligaments and tendons attach to bone, a process called enthesitis. This inflammation, driven by immune cells and cytokines like TNF-alpha, can trigger new bone formation. Although the exact reasons for syndesmophyte development are not fully understood, this persistent inflammatory process contributes to the ossification of spinal ligaments and discs.
Recognizing Symptoms and Getting a Diagnosis
Individuals developing syndesmophytes often experience symptoms such as chronic back pain, particularly in the lower back and buttocks, and morning stiffness. This stiffness typically lasts for at least 30 minutes and improves with activity rather than rest. As syndesmophytes progress and cause spinal fusion, a reduction in spinal mobility and flexibility becomes noticeable.
The diagnostic process primarily relies on imaging techniques. X-rays are commonly used to detect syndesmophytes, though they may not show growths in the early stages of the disease due to their slow development. Magnetic Resonance Imaging (MRI) scans can provide a more detailed view of spinal inflammation and may predict the development of new syndesmophytes. Clinicians combine imaging findings with a physical examination, assessing spinal mobility and tenderness, to arrive at a diagnosis.
Managing Syndesmophyte Progression
Managing conditions that cause syndesmophytes focuses on alleviating pain, reducing inflammation, and preserving spinal mobility. Non-steroidal anti-inflammatory drugs (NSAIDs) are often a first-line treatment to help control pain and inflammation. For more severe cases, biological treatments, such as anti-tumor necrosis factor (TNF) medications and monoclonal antibody treatments, can be prescribed to target the underlying inflammatory processes.
Physical therapy plays a significant role in maintaining flexibility and strengthening supporting muscles, which can help improve posture and function. Regular exercise programs, including group or individual sessions, and hydrotherapy, where exercises are performed in water, are often recommended. While there is currently no known treatment to completely halt syndesmophyte growth, these strategies aim to manage symptoms and slow the progression of spinal fusion. Surgery is generally considered only in rare, severe cases where spinal deformity significantly impacts a person’s function or causes neurological complications.