Lordosis distribution index for predicting mechanical complications after long-level fusion surgery: comparison of Global Alignment and Proportion score and Roussouly classification.

Objective: Both the Global Alignment and Proportion (GAP) score and Roussouly classification account for the lordosis distribution index (LDI), but the LDI of the GAP score (G-LDI) is typically set to 50%-80%, while the LDI of the Roussouly classification (R-LDI) varies depending on the degree of pelvic incidence (PI). The objective of this study was to validate the ability of the G-LDI to predict mechanical complications and compare it with the predictive probability of R-LDI in patients with long-level fusion surgery.

Methods: A total of 171 patients were divided into two groups: 93 in the nonmechanical complication group (non-MC group) and 78 in the mechanical complication group (MC group).

Reliability of facet fluid on preoperative MRI for prediction of segmental instability after decompression surgery for degenerative lumbar spinal stenosis.

Background: The purpose of this study is to determine whether preoperative facet fluid on MRI can help predict segmental instability (SI) after decompression surgery.

Methods: We analyzed 34 patients (14 men and 20 women, a total of 37 segments) who underwent decompression for degenerative lumbar spinal stenosis from June 2011 to August 2019 at a single institution. Mean age at the time of operation was 67.