Local and Widespread Pressure Pain Hyperalgesia Is Not Side Specific in Females with Unilateral Neck Pain that Can Be Reproduced during Passive Neck Rotation.

Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.

Craniocervical posture and trigeminal nerve mechanosensitivity in subjects with a history of orthodontic use: a cross-sectional study.

The purpose of the study was to evaluate whether, in asymptomatic subjects, there are differences in: (i) head posture while sitting and standing still and (ii) trigeminal nerve mechanosensitivity, between those who have a history of using orthodontics and those who do not. The sample consisted of 72 subjects (21 +/- 2.14 years): one group who had used orthodontics in the past (n = 37), and another group who had not had previous orthodontic treatment (n = 35). The authors measured the CranioVertebral Angle (CVA) while the subject was sitting and standing still by means of lateral photographs, and the pressure pain threshold (PPT) of the trigeminal nerve. The orthodontics group showed a more upright position of the head when sitting compared to the non-orthodontics group, with the difference being statistically significant (ANOVA test; p < 0.001; F1,70 = 16.705; R2 = 0.19), but not for the standing position (p = 0.538). The values of the PPT in the trigeminal nerve (supraorbital-V1, infraorbital-V2 and mandibular-V3) were lower on both sides (dominant and nondominant) in the non-orthodontics group. The between-group comparison (ANOVA test) showed statistically significant differences for the trigeminal nerve PPT in its different branches (V1 p = 0.001; F1,70 = 13.012; R2 = 0.15) (V2 p = 0.004; F1,70 = 9.103; R2 = 0.11) (V3 p = 0.005; F1,70 = 8.228; R2 = 0.10). Based on these observations, it was concluded that subjects with a history of orthodontic use show a better sitting craniocervical posture and mechano-sensitivity of the trigeminal nerve branches compared to the group that had not used orthodontics in the past.

Immediate changes in masticatory mechanosensitivity, mouth opening, and head posture after myofascial techniques in pain-free healthy participants: a randomized controlled trial.

OBJECTIVE: This study aimed to assess the immediate effects on masticatory muscle mechanosensitivity, maximal vertical mouth opening (VMO), and head posture in pain-free healthy participants after intervention with myofascial treatment in the temporalis and masseter muscles. METHODS: A randomized, double-blind study was conducted. The sample group included 48 participants (n=48), with a mean age of 21±2.47 years (18-29). Two subgroups were defined: an intervention group (n=24), who underwent a fascial induction protocol in the masseter and temporalis muscles, and a control group (n=24), who underwent a sham (placebo) intervention. The pressure pain threshold in 2 locations in the masseter (M1, M2) and temporalis (T1, T2) muscles, maximal VMO, and head posture, by means of the craniovertebral angle, were all measured. RESULTS: Significant improvements were observed in the intragroup comparison in the intervention group for the craniovertebral angle with the participant in seated (P<.001; F1,23=16.45, R2=0.41) and standing positions (P=.012, F1,23=7.49, R2=0.24) and for the pressure pain threshold in the masticatory muscles, except for M2 (P=.151; M1: P=.003; F1,23=11.34, R2=0.33; T1: P=.013, F1,23=7.25, R2=0.23; T2: P=.019, F1,23=6.41, R2=0.21). There were no intragroup differences for the VMO (P=.542). Nevertheless, no significant differences were observed in the intergroup analysis in any of the studied variables (P>.05). CONCLUSION: Myofascial induction techniques in the masseter and temporalis muscles show no significant differences in maximal VMO, in the mechanical sensitivity of the masticatory muscles, and in head posture in comparison with a placebo intervention in which the therapist's hands are placed in the temporomandibular joint region without exerting any therapeutic pressure.