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A subject-specific method to measure dynamic spinal alignment in adult spinal deformity
Pieter Severijns1, Thomas Overbergh2, Anaïsse Thauvoye3
1Department of Development and Regeneration, Faculty of Medicine, Institute for Orthopaedic Research and Training (IORT), KU Leuven, Leuven, Belgium; Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium; Clinical Motion Analysis Laboratory (CMAL), University Hospitals Leuven, Leuven, Belgium.
A new kinematic model using motion capture offers a valid and reliable method for assessing dynamic spinal alignment in adult spinal deformity (ASD). This approach moves beyond static X-rays to provide functional insights for improved clinical decision-making.
Area of Science:
- Biomechanical analysis
- Spinal imaging and kinematics
- Adult spinal deformity (ASD) research
Background:
- Current standard for spinal alignment measurement in adult spinal deformity (ASD) relies on static radiography.
- Static measurements do not capture dynamic spinal behavior or patient compensation strategies.
- There is a need for tools to assess dynamic spinal alignment for a comprehensive understanding of ASD functionality.
Purpose of the Study:
- Introduce a novel kinematic model for measuring dynamic spinal parameters in ASD.
- Validate the accuracy and assess the reliability of this new polynomial function-based model.
- Incorporate subject-specific anatomy into the dynamic spinal alignment assessment.
Main Methods:
- Compared a polynomial kinematic model with traditional X-ray measurements in 23 ASD patients and 18 controls.
- Utilized motion capture technology with anatomy-corrected marker positions.
- Assessed concurrent validity, test-retest reliability, and inter/intra-rater reliability during standing and sit-to-stand (STS) movements.
Main Results:
- Demonstrated good to excellent correlations (r>0.75) between the polynomial method and X-ray parameters, especially with anatomy correction.
- The polynomial method showed good to excellent reliability (Intraclass Correlation Coefficients >0.75), comparable or superior to radiographic measurements.
- Excellent reliability was observed during the sit-to-stand maneuver.
Conclusions:
- The polynomial kinematic model, incorporating subject-specific anatomy, provides a valid and reliable method for dynamic spinal alignment assessment in both healthy and deformed spines.
- This technique enables a shift from static radiographic evaluations to dynamic, functional assessments in ASD.
- Dynamic spinal alignment data can inform clinical decision-making and guide new treatment strategies.
