Spinopelvic balance: new biomechanical insights with clinical implications for Parkinson's disease.

PURPOSE: The aim of this study was to describe the disease-related sagittal balance changes in relation to the sacropelvic morphology of PD patients with different durations of disease. METHODS: Thirty-one consecutive Parkinson's disease patients (26 males, 5 females; age 55-83 years) participated in the cross-sectional study. The clinical assessment included: Hoehn Yahr score; plumb line distance from the spinous process of C7, kyphosis apex, spinous process of L3 and S1. Lumbar lordosis (LL), thoracic kyphosis (TK), spinosacral angle, spinopelvic angle, spinal tilt, pelvic incidence, sacral slope (SS) and pelvic tilt were radiographically assessed. RESULTS: Radiographic spinopelvic angles appeared normal, but many patients presented variations from normality. In particular, pelvic tilt increased and SS decreased; spinosacral and spinopelvic angles were greatly reduced compared to healthy people, and spinal tilt increased. Unlike TK, LL was well correlated with most of the parameters. CONCLUSIONS: Sagittal balance evaluation provides new valuable insights for biomechanical understanding of PD patients. Specific spinal parameters (spinosacral, spinopelvic and spinal tilt angles), and their clinical correlation, as well as pelvic parameters like pelvic tilt and sacral slope, appear particularly interesting for their clinical implications in terms of spinal deformities correction in PD population.