A spinal manipulative therapy altered brain activity in patients with lumbar disc herniation: A resting-state functional magnetic resonance imaging study

Abstract

Purpose: Lumbar disc herniation (LDH) is one of the leading causes of low-back pain and results in a series of clinical symptoms, including pain, reflex loss, and muscle weakness. Spinal manipulative therapy (SMT) can relieve pain and promote internal and external stabilization of the lumbar spine. In this study, we investigated whether the brain alterations of LDH patients with SMT were frequency-dependent based on the calculation of Amplitude of Low-Frequency Fluctuations (ALFF) and fractional ALFF (fALFF). Further, we established a cohort of LDH patients to evaluate the contribution of SMT treatments to brain functional reorganization.

Methods: A total of 55 participants, including 27 LDH patients and 28 health controls (HCs), were collected. All LDH patients underwent two fMRI scans (before SMT and after the sixth SMT session). To represent LDH-related brain oscillatory activities, we calculated the ALFF and fALFF in the conventional band (0.01-0.08 Hz), the slow-4 band (0.027-0.073 Hz), and the slow-5 band (0.01-0.027 Hz). Moreover, we extracted ALFF and fALFF values in clusters with significant differences to evaluate the SMT effect.

Results: Compared with HCs, the LDH patients before SMT (LDH-pre) exhibited increased fALFF in right lingual gyri in the conventional band, and showed increased fALFF in left Cerebelum_Crus1 in the slow-4 band. We further examined the abnormal brain activities changes before and after the SMT intervention. The ALFF and fALFF values of LDH-pre group were higher than those of the HCs and LDH-pos groups. After SMT, the increased ALFF and fALFF values were suppressed for patients in conventional band and slow-4 band.

Conclusion: The present study characterized the altered regional patterns in spontaneous neural activity in patients with LDH. Meanwhile, SMT is an effective treatment of LDH, and we supposed that it might have been involved in modulating dysfunctional brain regions which are important for the processing of pain. The findings of the current study may provide new insights to understand pathological mechanism of LDH.

Keywords: amplitude of low-frequency fluctuations; frequency dependence; lumbar disc herniation; resting-state functional magnetic resonance imaging; spinal manipulative therapy.

FIGURE 1

Spinal Manipulative Therapy (SMT) performed by rolling (A), kneading (B), plunking (C), pushing (D) to relax the muscles in the lower back area for the purpose of alleviating pain and improving lumbar function.

FIGURE 2

ALFF values using two-sample t-tests in the conventional band between LDH-pre patients and HCs. Increased ALFF values have been shown in the right lingual gyri in LDH-pre group compared with HCs. (GRF correction, voxel p < 0.05 and cluster p < 0.05). Color bar indicates the t score (L, left; R, right).

FIGURE 3

fALFF values using two-sample t-tests in slow-4 band between LDH-pre patients and HCs. Increased fALFF values have been shown in the left Cerebelum_Crus1 in LDH-pre group compared with HCs (GRF correction, voxel p < 0.05 and cluster p < 0.05). Color bar indicates the t score (L, left; R, right).

FIGURE 4

The mean ALFF and fALFF values of signals extracted from right lingual gyri of each participant. The LDH patients and HCs were compared using two-sample t-tests, and LDH patients before and after SMT were compared by paired t-tests. ^** Indicates significance level at p < 0.01 (two -tailed). (A,B) The mALFF value (A) and mfALFF value (B) in the conventional band from the right lingual gyri of the HC, the patients with LDH before (LDH-pre) and after the SMT treatments (LDH-pos). (C,D) The mALFF value (C) and mfALFF value (D) in the slow-4 band from the from the same brain region of the three group. (E,F) The mALFF value (E) and mfALFF value (F) in the slow-5 band.

FIGURE 5

The mean ALFF and fALFF values of signals extracted from left Cerebelum_Crus1 of each participant. The LDH patients and HCs were compared using two-sample t-tests, and LDH patients before and after SMT were compared by paired t-tests. ^** Indicates significance level at p < 0.01 (two -tailed), ^*** Indicates significance level at p < 0.001 (two -tailed). (A,B) The mALFF value (A) and mfALFF value (B) in the conventional band from left Cerebelum_Crus1 of the HC, the patients with LDH before (LDH-pre) and after the SMT treatments (LDH-pos). (C,D) The mALFF value (C) and mfALFF value (D) in the slow-4 band from the from the same brain region of the three group. (E,F) The mALFF value (E) and mfALFF value (F) in the slow-5 band.