Computational modeling of posteroanterior lumbar traction by an automated massage bed: predicting intervertebral disc stresses and deformation.
Luis Cardoso, Niranjan Khadka, Jacek P Dmochowski and 5 others
PMID 36189059WHAT IT FOUND
Computer models predict that posteroanterior traction from an automated massage bed creates tensile stresses in lumbar discs that counteract compression.
However, predicted stress relief decreases significantly as BMI increases, with obese models showing up to 79% less stress change than normal-weight models.
Key findings
01Posteroanterior traction generated tensile stresses in lumbar discs that are opposite in nature to compressive stresses, potentially counterbalancing them.
02The magnitude of stress relief in the lumbar discs was inversely proportional to BMI, with normal-weight models showing the highest stress relief.
03Compared to the normal BMI model, predicted stress magnitudes were reduced by approximately 14% in overweight, 51% in moderate obese, and 79% in severe obese models.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
This is a computational study, not a clinical trial. It models physics but does not measure pain or function in actual patients. The models were based on a single male subject's anatomy, so they do not account for variations in spine curvature, disc health, or sex differences. The tissue properties were simplified (linear elastic), which may not accurately reflect real biological behavior under load. The study only simulated posteroanterior traction and did not account for heat or dynamic movement.
Declared interests
The study was funded by a grant from Ceragem, the manufacturer of the massage bed. The funder provided device parameters and reviewed the simulation results. Several authors were employed by or held equity in companies related to the device or its technology.
The easy way to misread this
Do not interpret these predicted stress changes as evidence that the device reduces pain or improves function in patients. This is a biomechanical model that has not been validated against clinical outcomes, and the manufacturer funded and influenced the study.