157) Humans with Inducible Symptoms of Low Back Pain Show Intervertebral Disc Changes in the Lumbar Spine during Prolonged Standing

LBP symptoms can be induced in back-healthy individuals in prolonged standing and are relieved upon exiting standing [1]. These individuals who develop LBP (pain developers -PDs) are 3 times more likely to develop a clinical episode of LBP within two years than their non-pain developer (NPD) counterparts [2]. Yet the specific anatomical changes that provoke these LBP symptoms remain unknown. We hypothesized that PDs have distinct adaptations in each intervertebral disc (IVD) level compared to NPDs. We investigated the changes in spinal alignment (Cobb angle) and local IVD structure over time in PDs. Forty human subjects (age 18-30, BMI < 30, 21F, 19M) with no history of LBP were recruited and consented. Participants were first imaged in supine and then in standing, and they self-reported the LBP symptoms using a VAS every 15 minutes in a positional-MRI (pMRI). PDs (12F, 8M) exhibit a sustained VAS score greater than 0; NPDs (9F, 11M) did not. Cobb angle, intervertebral (IV) angle, anterior, posterior height ratio (A/P ratio), and IVD width were measured at each time point for the participants. Female and male PDs exhibit different A/P ratios (p= 0.028) and IVD widths (p< 0.001). The IV angle is affected by sex and pain (p= 0.03). This is the first study to examine the structural adaptations of local IVD levels in PDs using a pMRI. Although the Cobb angle did not differ, IV angle, A/P ratio and IVD width did vary by lumbar level. Our data also shows that the IVDs of PDs adapt differently by sex in prolonged standing compared to NPDs. This study identifies a connection between local structural measurements and standing-induced LBP symptoms. This work was supported by the NIH P30AR057235, T32EB018266, and K01AR069116. LBP symptoms can be induced in back-healthy individuals in prolonged standing and are relieved upon exiting standing [1]. These individuals who develop LBP (pain developers -PDs) are 3 times more likely to develop a clinical episode of LBP within two years than their non-pain developer (NPD) counterparts [2]. Yet the specific anatomical changes that provoke these LBP symptoms remain unknown. We hypothesized that PDs have distinct adaptations in each intervertebral disc (IVD) level compared to NPDs. We investigated the changes in spinal alignment (Cobb angle) and local IVD structure over time in PDs. Forty human subjects (age 18-30, BMI < 30, 21F, 19M) with no history of LBP were recruited and consented. Participants were first imaged in supine and then in standing, and they self-reported the LBP symptoms using a VAS every 15 minutes in a positional-MRI (pMRI). PDs (12F, 8M) exhibit a sustained VAS score greater than 0; NPDs (9F, 11M) did not. Cobb angle, intervertebral (IV) angle, anterior, posterior height ratio (A/P ratio), and IVD width were measured at each time point for the participants. Female and male PDs exhibit different A/P ratios (p= 0.028) and IVD widths (p< 0.001). The IV angle is affected by sex and pain (p= 0.03). This is the first study to examine the structural adaptations of local IVD levels in PDs using a pMRI. Although the Cobb angle did not differ, IV angle, A/P ratio and IVD width did vary by lumbar level. Our data also shows that the IVDs of PDs adapt differently by sex in prolonged standing compared to NPDs. This study identifies a connection between local structural measurements and standing-induced LBP symptoms. This work was supported by the NIH P30AR057235, T32EB018266, and K01AR069116.