Default mode network and dorsal attentional network connectivity changes as neural markers of spinal manipulative therapy in lumbar disc herniation

Spinal manipulative therapy (SMT) has been shown to significantly alleviate pain in patients with lumbar disc herniation (LDH), with its effects closely associated with brain function modulation. This study investigates the neural biomarkers linked to pain relief efficacy following a complete SMT treatment cycle in LDH patients. A total of 59 LDH patients were randomized into two groups: SMT treatment (Group 1, n = 28) and sham treatment (ST) (Group 2, n = 31). A matched healthy control group (Group 3, n = 28) was also included. Functional magnetic resonance imaging (fMRI) was performed on LDH patients at two time points (TPs)-before (TP1) and after (TP2) treatment-while healthy controls were scanned once. Clinical assessments were conducted using the Visual Analogue Scale (VAS) and the Japanese Orthopaedic Association (JOA) scale. Post-treatment results indicated significant improvements in both VAS and JOA scores for Group 1, while the improvement was limited to VAS scores for Group 2. Graph properties analysis revealed notable differences in brain network connectivity between LDH patients and healthy controls, particularly between the left precentral gyrus (left PreCG) and left inferior frontal gyrus, opercular part (left IFGoperc). Enhanced functional connectivity (FC) was observed in Group 1, notably between the right angular gyrus (right ANG) and the left middle orbital gyrus (left ORBmid), with right ANG showing a significant positive correlation with clinical scores. This study identifies the sensorimotor network-salience network are significantly activated in chronic pain among LDH patients. The default mode network-dorsal attention network may serve as key neural biomarkers for the efficacy of SMT treatment in alleviating pain in LDH.