Purpose: Non-specific chronic low back pain (CLBP) is one of the most common worldwide painful syndrome among the adult population without clear medical evidence and specific diagnosis, while the cure of CLBP patients is resistant to diverse pharmacological and non-pharmacological prescriptions. Repetitive transcranial magnetic stimulation (rTMS) as a non-invasive technique in spite of its prospective treatment effectiveness has not been examined deeply for the recovery solution of CLBP, yet. This study aimed to find out pre and post rTMS stimulation in neuronal vesicle activities using resting-fMRI brain functional connectivity (FC) data analysis.
Methods: The pain intensity of nine non-specific CLBP patients (age 50±10.39) was determined by the conventional method of visual analog scale (VAS) before and 2-4 days after 20 Hz rTMS via an eight-shaped coil over the motor cortex. Stimuli were provided in field intensity of 95% of the motor thresholds and trains of 40 pulses, followed by a 28sec rest period. The rs-fMRI data were collected using a Siemens 3T MRI scanner with the standard 64-channel head coil, while, anterior cingulate cortex (AC) as a key pain region selected for seed-based connectivity (SBC) analysis with other pain regions in every session.
Results: Pre and post rTMS stimulation execution results showed the mean pain intensity of patients as 8.17±1.20 and 3.85±0.95, respectively (recovery rate=53%). The functional connectivity beta values represent Fisher-transformed correlation coefficients between AC and insula, supramarginal gyrus (SMG), and prefrontal cortex (PFC) in pre-stimulation session were 0.67, 0.44, and 0.53, while in post-stimulation session significantly decreased as 0.54, 0.28, and 0.45, respectively (p-FDR < 0.05).
Conclusion: Significant decremental brain connectivity coefficients in conformity with conventional VAS evaluation of CLBP patients showed the recovery in pain-related regions as the criteria for the effectiveness of rTMS pain reduction in CLBP patients.