Spine surgery prediction tools
Time-to-event risk of adjacent segment disease after lumbar fusion, driven by sagittal alignment, the levels fused and surgical technique.
Key terms
- Adjacent segment disease (ASD)
Adjacent segment disease is symptomatic degeneration at the spinal level next to a fusion. It is distinguished from adjacent segment degeneration, which is seen on imaging without symptoms.
- PI-LL mismatch
PI-LL mismatch is pelvic incidence minus lumbar lordosis. A mismatch over about 10 degrees indicates sagittal malalignment and is linked to worse outcomes after lumbar fusion.
- Survival analysis (time-to-event modeling)
Survival analysis models how long until an event happens, while correctly handling patients whose follow-up ends before the event (censoring).
- SHAP (Shapley additive explanations)
SHAP explains an individual prediction by splitting it into contributions from each input feature, based on Shapley values from game theory.
Research and educational tools. Not for clinical decision-making.