Associations between longitudinal resting-state functional connectivity changes and pain recovery following condoliase injection for lumbar disc herniation.

Abstract

Intradiscal condoliase injection is an established minimally invasive treatment for symptomatic lumbar disc herniation (LDH), but its effects on central neural processing remain poorly understood. This study investigated longitudinal alterations in resting-state functional connectivity (rsFC) following condoliase injection and their associations with pain improvement. Twenty-six patients with LDH who achieved clinically meaningful pain reduction (≥50% reduction on the Visual Analogue Scale) underwent longitudinal resting-state fMRI. Seed-to-voxel analyses identified rsFC alterations between pre-treatment and 3 months post-treatment, focusing on the salience network (SN). Associations between functional connectivity changes (ΔFC) and pain improvement rates were evaluated using Spearman's rank correlation coefficients with Benjamini-Hochberg false discovery rate (FDR) correction across identified regions of interest (ROIs). Condoliase treatment significantly altered SN-related cerebellar and temporoparietal pathways. Specifically, connectivity decreased between the anterior insula (AI) and a brainstem/Vermis X cluster, while it increased between the supramarginal gyrus (SMG) and temporal occipital fusiform cortex (TOFC). Pain improvement rates correlated with ΔFC in the AI-Vermis X (ρ = 0.47, p = 0.015) and SMG-TOFC (ρ = -0.48, p = 0.014) pathways. Both remained significant after FDR correction (q = 0.045). Pain improvement following condoliase injection is accompanied by longitudinal reorganization of SN-related functional connectivity, highlighting salience-cerebellar and salience-temporoparietal brain plasticity during recovery from LDH.