Cortical Surface Functional Changes After Lever Positioning Manipulation for Lumbar Disc Herniation

Participants with lumbar disc herniation receive lever positioning manipulation three times weekly for 4 weeks, approximately 20 minutes per session. Clinical outcome scales and MRI are obtained before treatment and at week 4 after the first session. The target is 30 participants completing the required assessments; withdrawals will be replaced as needed and included in cumulative enrollment.

Delivered to participants with LDH by an experienced rehabilitation practitioner three times weekly for 4 weeks, approximately 20 minutes per session. With the participant's hips and knees flexed and legs crossed, the practitioner identifies the target lumbar segment, stabilizes it with the elbow, holds the ankles, and lifts and pulls the legs upward and inward to the pre-thrust position. A rapid lever-pulling maneuver is then performed while the participant exhales.

Age- and sex-matched healthy controls undergo baseline eligibility assessment and MRI only, without study intervention or patient clinical outcome scales. The target is 30 participants completing the baseline assessment. Withdrawals before completion will be replaced as needed and included in cumulative enrollment.

Resting-state functional MRI will assess the amplitude of low-frequency blood oxygen level-dependent (BOLD) fluctuations on the cortical surface. Mean-normalized ALFF in the 0.01-0.08 Hz band will be calculated relative to the mean cortical ALFF. Within-participant change from baseline to week 4 will be assessed in participants with LDH.

Regional homogeneity will be calculated as Kendall's coefficient of concordance between the BOLD time series at each cortical vertex and its one-ring surface neighbors. Scores range from 0 to 1, with higher values indicating greater local temporal concordance. Within-participant change from baseline to week 4 will be assessed in participants with LDH.

Global functional connectivity density will be quantified as the proportion of other cortical vertices whose BOLD time series have a Pearson correlation greater than 0.6 with each vertex. Self-connections will be excluded. Within-participant change from baseline to week 4 will be assessed in participants with LDH.

Left and right insular cortex seeds will be defined using independent anatomical labels. Seed-to-vertex functional connectivity will be calculated using Pearson correlation followed by Fisher z transformation. Within-participant change from baseline to week 4 will be assessed in participants with LDH.

Cortical regions will be defined using the Schaefer 400-region parcellation. Region-to-region functional connectivity will be calculated using Pearson correlation between regional BOLD time series followed by Fisher z transformation. Changes in unique region-pair connectivity values from baseline to week 4 will be assessed in participants with LDH.

Using the seven Yeo networks, within-network and between-network connectivity will be quantified as mean Fisher-z-transformed region-to-region connectivity. The measures include seven within-network and 21 between-network values. Within-participant changes from baseline to week 4 will be assessed in participants with LDH.

The first three cortical functional connectivity gradients will be estimated from regional connectivity profiles using diffusion-map embedding and aligned to a fixed independent reference. Regional gradient coordinates will be reported in arbitrary units. Within-participant changes from baseline to week 4 will be assessed in participants with LDH.

Functional gradient eccentricity will be calculated as each cortical region's Euclidean distance from the centroid of all regions in the space of the first three aligned functional gradients. Values will be reported in arbitrary units. Within-participant change from baseline to week 4 will be assessed in participants with LDH.

Pain intensity will be assessed using a 10-cm horizontal Visual Analog Scale, recorded on a 0-10 scale, where 0 indicates no pain and 10 indicates the worst imaginable pain. Change from baseline to week 4 will be assessed in participants with LDH.

Lumbar neurological and functional status will be assessed using the Japanese Orthopaedic Association score, reported on a 0-29 scale. Higher scores indicate better status. Change from baseline to week 4 will be assessed in participants with LDH.

Low-back-pain-related disability will be assessed using the Oswestry Disability Index, reported on a 0-100% scale. Higher scores indicate greater disability. Change from baseline to week 4 will be assessed in participants with LDH.

Anxiety symptoms will be assessed using a Chinese-language version of the 20-item Zung Self-Rating Anxiety Scale. The total raw score ranges from 20 to 80 and is converted to a standard/index score ranging from 25 to 100 by multiplying by 1.25. Higher standard scores indicate more severe anxiety symptoms. Change in standard score from baseline to week 4 will be assessed in participants with LDH.

Depressive symptoms will be assessed using a Chinese-language version of the 20-item Zung Self-Rating Depression Scale. The total raw score ranges from 20 to 80 and is converted to a standard/index score ranging from 25 to 100 by multiplying by 1.25. Higher standard scores indicate more severe depressive symptoms. Change in standard score from baseline to week 4 will be assessed in participants with LDH.

The number and proportion of participants experiencing adverse events will be recorded throughout the 4-week treatment course. Severity and relationship to intervention will be assessed. Vital signs and treatment-related discomfort will be checked at each treatment session.