Can thoracolumbar scoliosis lead to Degenerative Disc Disease (DDD)?

Thoracolumbar Scoliosis and Degenerative Disc Disease

Yes, thoracolumbar scoliosis can lead to degenerative disc disease (DDD) due to asymmetric loading and altered biomechanics of the spine. 1

Relationship Between Scoliosis and Disc Degeneration

Pathophysiological Mechanism

• Asymmetric degeneration leads to increased asymmetric load on the spine, creating a progressive cycle of deformity and degeneration 2
• Altered biomechanics from scoliosis cause uneven pressure distribution across intervertebral discs, accelerating degenerative changes
• Sagittal imbalance, particularly thoracic flat back (reduced thoracic kyphosis), is a significant risk factor for developing lumbar DDD 3

Types of Adult Scoliosis Associated with DDD

Adult scoliosis can be classified into four major types 2:

1. Primary degenerative scoliosis (de novo): Develops due to asymmetric disc and/or facet joint degeneration
2. Progressive idiopathic scoliosis: Adolescent curves that progress in adulthood, often with secondary degeneration
3. Secondary adult curves: Due to pelvic obliquity, leg length discrepancy, or metabolic bone disease
4. Post-surgical progression: Adjacent segment degeneration after fusion

Risk Factors for DDD in Scoliosis Patients

Sagittal Alignment Factors

• Thoracic flat back: Patients with thoracic kyphosis <15° have significantly higher rates of lumbar DDD compared to those with normal kyphosis (>28°) 3
• Positive sagittal imbalance: Forward displacement of the spine is associated with advanced DDD 3
• Altered pelvic parameters: Increased pelvic tilt may contribute to degenerative changes 4

Patient-Specific Factors

• Age: Patients over 65 years have higher risk of developing adjacent segment degeneration 5
• Pre-existing disc degeneration: The presence of disc degeneration on preoperative MRI significantly increases risk of progression 5

Clinical Implications

Symptoms and Presentation

• Back pain is the predominant symptom in patients with scoliosis-related DDD 2
• Leg pain and claudication symptoms may develop with progression
• Neurological deficits are rare but possible in advanced cases

Diagnostic Approach

• Standing full-spine radiographs (posteroanterior and lateral views) are essential to evaluate curve severity, pattern, and sagittal balance 1
• MRI is recommended to assess disc degeneration and potential intraspinal abnormalities 1
• CT may be useful for presurgical planning or when MRI is contraindicated 1

Management Considerations

Non-Surgical Approaches

• NSAIDs/COXIBs at maximum tolerated dosage for pain relief 1
• Maintaining normal physical activity while avoiding asymmetric loading on the spine 1
• Limiting high-impact activities in patients with progressive curves 1

Surgical Considerations

• Surgery may be indicated for curves >50° or when significant pain, cosmetic concerns, or respiratory compromise are present 1
• Minimally invasive approaches show promise with lower blood loss and shorter hospital stays 6
• Attention to sagittal balance correction is crucial, as failure to address thoracic flat back may lead to accelerated DDD 3

Common Pitfalls and Considerations

• Inadequate assessment of sagittal balance parameters can lead to suboptimal outcomes
• Failure to recognize pre-existing disc degeneration may result in underestimating progression risk
• Adjacent segment degeneration is a significant concern after fusion procedures, occurring in up to 44.9% of patients within 48 months 5

By understanding the relationship between thoracolumbar scoliosis and DDD, clinicians can better anticipate, diagnose, and manage these interconnected conditions to improve patient outcomes.