Spinal Flexibility After Scoliosis Surgery in Teenage Girls
Teenage girls experience significant reduction in spinal flexibility after scoliosis surgery, with postoperative decreases of approximately 41% in flexion-extension, 51% in lateral bending, and 59% in axial rotation. 1
Impact on Spinal Mobility
Posterior spinal fusion with instrumentation, the standard surgical technique for adolescent idiopathic scoliosis (AIS) with curves exceeding 50 degrees, significantly affects trunk mobility in all planes:
- Sagittal plane (forward/backward bending): 41% reduction in range of motion
- Coronal plane (side-to-side bending): 51% reduction
- Transverse plane (twisting/rotation): 59% reduction
The extent of flexibility loss correlates with the lowest instrumented vertebra (LIV) - the lower the fusion extends, the greater the loss of forward flexion mobility 1. This is particularly important since AIS predominantly affects females at a 10:1 ratio compared to males for developing larger curves 2.
Factors Affecting Post-Surgical Flexibility
Several factors influence the degree of flexibility loss:
- Fusion level: More distal LIV fusions (extending lower into the lumbar spine) result in greater limitation of peak forward flexion 1
- Fusion extent: Typically, fusions extend from T3 or T4 to as low as L4, depending on curve pattern 2, 3
- Age at surgery: Surgery is typically performed in adolescents with curves exceeding 40-50 degrees 2, 4
Functional Implications
Despite reduced flexibility, research shows some positive functional adaptations after surgery:
- Weight-shifting ability: By 2 years post-operation, patients show improvements in volitional weight-shifting compared to their pre-operative baseline 5
- Weight-bearing symmetry: Surgery helps improve the weight-bearing asymmetry that's present before surgery 5
Growth Considerations
An important consideration for teenage girls undergoing spinal fusion is the effect on growth:
- Spinal fusion does retard the longitudinal growth of the spine
- However, overall standing height is generally unaffected because the loss in spinal length is compensated by an increase in leg length 6
- This results in disproportionately longer legs compared to arm length in girls who undergo spinal fusion 6
Clinical Implications and Recommendations
When counseling teenage girls about scoliosis surgery:
- Be transparent about the expected 40-60% reduction in spinal mobility across all planes of movement
- Explain that flexibility loss is greater when fusion extends lower into the lumbar spine
- Reassure that functional adaptations occur over time, with improvements in weight-shifting ability by 2 years post-surgery
- Discuss that while spinal growth is affected, overall height is typically preserved through compensatory leg growth
Common Pitfalls to Avoid
- Underestimating mobility loss: Failing to adequately prepare patients for the significant reduction in spinal flexibility
- Overlooking functional adaptations: Not recognizing that patients develop compensatory mechanisms that improve function over time
- Neglecting psychological impact: The American College of Radiology notes that overlooking the psychological impact of reduced mobility is a common pitfall in scoliosis treatment 2
- Inappropriate activity restrictions: While high-impact activities may need limitation in patients with progressive curves, maintaining normal physical activity is recommended 2
Understanding these changes in spinal flexibility is crucial for setting appropriate expectations and providing comprehensive care for teenage girls undergoing scoliosis surgery.