At the Osman Laboratory, researchers set out to test a simple but important question: Does twisting the spine change the pressure inside an intervertebral disc? This question matters because some theories suggest spinal manipulation might relieve back pain by reducing pressure within the disc.
In a controlled laboratory study published in Spine (2007), the team examined human lumbar spine segments and measured intradiscal pressure while applying small rotational forces (torsion). Each specimen was also subjected to a compressive load to simulate the weight the spine normally carries.
The results were clear: small amounts of spinal twisting did not produce significant changes in intradiscal pressure or disc height. In other words, mild torsion alone was unlikely to decompress the disc nucleus.
These findings suggest that if spinal manipulation provides relief for patients, the mechanism is probably not due to a simple reduction of disc pressure. Instead, other factors—such as joint mechanics, muscular responses, or nervous system effects—may play a larger role.
This work highlights how careful biomechanical testing helps clarify long-standing assumptions about spinal mechanics and treatment approaches.
Reference: Spine. 2007; “Torsion-Induced Pressure Distribution Changes in Human Intervertebral Discs: An In Vitro Study.”