Physics-first forward model of the lumbar spine: how the disc, foramen and nerve root change before and after treatment, over time.
Research prototype, not for clinical use
Beta demo, for research and illustration only. Do not enter real patient data or PHI. Any identifiers (name, MRN, DOB, address) typed into the report box are automatically masked in your browser before anything is sent off the page.
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Patient findings
3.0 mm
13.0 mm
4
MRI report → findingsIdentifiers are auto-masked in your browser before sending. Beta, do not enter real PHI.
Forward model:
OpenSim Bruno thoracolumbar model · actual L1-S1 geometry
Lumbar spine (L1-L5 and sacrum) with intervertebral discs, from the validated OpenSim Bruno thoracolumbar model. The bones are the actual model geometry; the discs are synthesized in the inter-body gaps (the model represents discs as joints, not meshes). The yellow tubes are the exiting nerve roots; the L4-L5 pair reddens as the model predicts compression. Rotating oblique view; drag to rotate, scroll or pinch to zoom.
vertebradiscnerve roothover a part for detail
Simulated pre-op MRI (sagittal)generated from the inputs, not a real scan
This is a physics-based forward model of the anatomy: it shows how the disc, foramen and exiting nerve root change with each treatment, immediately and over time, from literature priors. It deliberately does not predict clinical outcomes (pain relief, satisfaction, or a recommendation), since that requires patient data and validation that this tool does not have.
How this works, and what is not yet real physics
Now (reduced-order): nerve-root compression probability from foraminal geometry, calibrated to Hasegawa (1995) critical heights (posterior disc height ≤4 mm, foraminal height ≤15 mm). Indirect decompression uses the Formica 2020 regression (foraminal-height gain = 0.82 × disc height restored; HSS J 16:143-154). This is literature-prior, not yet a biomechanical simulation.
The diagram is a schematic side view: disc height drives foraminal height, and the exiting nerve root is colored by the model's compression estimate. Hover any structure for a label. It is illustrative, not a rendering of the patient's own anatomy.
Disc-degeneration trajectory over time (post-op, 6 mo, 1 yr, 2 yr) is a literature-anchored placeholder. The open machinery to build it properly exists (poroelastic + Donnan osmotic mechanics, nutrient-transport reaction-diffusion, and Lotz's stress×time apoptosis law); Aaron Fields' physics is the patient-specific core. Every constant's source is documented separately.
Scope, deliberately limited: this is a forward model of the anatomy only. It shows how the disc, foramen and nerve root change with each treatment over time. It does not predict pain relief, satisfaction, or a treatment recommendation, because that link from anatomy to patient-reported outcome needs patient data and validation this tool does not have.
Roadmap: swappable engine, FEBio open lumbar FE, OpenSim thoracolumbar (adjacent-segment loading), and the UCSF Fields/Lotz disc physics (Aaron's unpublished disc-degeneration + adjacent-stress model, plus the Fields/Lotz qMRI and apoptosis calibrations) as the patient-specific core, with UCSF patient data for validation.