Occupancy Rate of Pedicle Screw Below 80% is a Risk Factor for Upper Instrumented Vertebral Fracture After Adult Spinal Deformity Surgery.

Study Design: Retrospective study.

Objective: To determine whether an occupancy rate of a pedicle screw (ORPS) <80% in an upper instrumented vertebra (UIV) is a risk factor for UIV fracture (UIVF).

Summary Of Background Data: The ratio of the length of the pedicle screw to the anteroposterior diameter of the vertebral body at the UIV is defined as ORPS.

Low occupancy rate of the pedicle screw in the vertebral body leads to upper instrumented vertebral fracture.

Upper instrumented vertebra (UIV) fracture in adult spinal deformity surgery leads serious complications, such as spinal cord injury in 0.5-0.8%.

Effect of sagittal shape on proximal junctional kyphosis following thoracopelvic corrective fusion for adult spinal deformity: postoperative inflection vertebra cranial to T12 is a significant risk factor.

Study Design: This was a retrospective analysis of a prospectively collected consecutive case series of patients with adult spinal deformity (ASD).

Objective: This study aimed to investigate the impact of the geometrical sagittal shape of the corrected spine on the development of proximal junctional kyphosis (PJK). Several studies have documented risk factors for PJK in ASD surgery.