Short-term increase in discs’ apparent diffusion is associated with pain and mobility improvements after spinal mobilization for low back pain

Pain perception, trunk mobility and apparent diffusion coefficient (ADC) within all lumbar intervertebral discs (IVDs) were collected before and shortly after posterior-to-anterior (PA) mobilizations in 16 adults with acute low back pain. Using a pragmatic approach, a trained orthopaedic manual physical therapist applied PA mobilizations to the participants’ spine, in accordance with his examination findings. ADC(all) was computed from diffusion maps as the mean of anterior (ADC(ant)), middle (ADC(mid)), and posterior (ADC(post)) portions of the IVD. After mobilization, pain ratings and trunk mobility were significantly improved and a significant increase in ADC(all) values was observed. The greatest ADC(all) changes were observed at the L(3)-L(4) and L(4)-L(5) levels and were mainly explained by changes in ADC(ant) and ADC(post), respectively. No significant changes in ADC were observed at L(5)-S(1) level. The reduction in pain and largest changes in ADC observed at the periphery of the hyperintense IVD region suggest that increased peripheral random motion of water molecules is implicated in the IVD nociceptive response modulation. Additionally, ADC changes were observed at remote IVD anatomical levels that did not coincide with the PA spinal mobilization application level.