Compensatory Mechanism of Maintaining the Sagittal Balance in Degenerative Lumbar Scoliosis Patients with Different Pelvic Incidence.

The APPA-4 is reliable as degree of the pelvic sagittal retroversion. In degenerative lumbar scoliosis, patients with smaller PI tended to rely more on the pelvic retroversion to maintain the sagittal balance than patients with larger PI, or patients with smaller PI were likely to start up the pelvic retroversion compensatory mechanism earlier than the patients with larger PI.