Can the positional release technique affect central sensitization in patients with chronic tension-type headache? A randomized clinical trial

Objective: To investigate whether the positional release technique (PRT) affects central sensitization in patients with chronic TTH.

Design: Randomised controlled trial with concealed allocation, assessor blinding and intention-to-treat analysis.

Setting: Two university neurology clinics.

Participants: 32 patients with TTH and MTrPs in their cervical muscles.

Intervention: Patients in the PRT group received 10 treatment sessions for each of their MTrPs during 5 weeks. All participants were allowed to use ibuprofen 200 mg for their headaches during the study.

Main outcome measures: The primary outcome measure was brain metabolite profile and secondary outcome measures were headache frequency and intensity, McGill score, and pressure pain threshold, which were evaluated in each participant during 5 weeks with proton magnetic resonance spectroscopy, patients' self-reports, the McGill Pain Questionnaire and a pressure algometer.

Results: Analysis of the data from 26 patients showed that headache frequency (p=0.001), headache intensity (p=0.002), McGill score (p=0.003), and local PPT (p=0.003) changed significantly after PRT. Myo-inositol/creatine concentration ratio in the somatosensory cortex (p=0.041) decreased significantly in the control group. Furthermore, there were significant differences between groups in headache frequency (p<0.001), headache intensity (p<0.001), McGill score (p<0.001), local PPT (p=0.004), distal PPT (p=0.041), and glutamate-glutamine/creatine concentration ratio in the thalamus (p=0.014).

Conclusion: These findings indicate that despite the improvement in clinical symptoms, PRT did not affect central sensitization in patients with TTH.

Keywords: brain; central sensitization; chronic pain; hyperalgesia; metabolite; spectroscopy.