Immediate Effects of Various Physical Medicine Modalities on Pain Threshold of an Active Myofascial Trigger Point

Abstract

Objectives: To study the immediate effectiveness of treatment on an active myofascial trigger point with physical medicine modalities, including spray and stretch, hydrocollator superficial heat, ultrasound deep heat, and deep pressure soft tissue massage. Methods: Eighty-four patients with myofascial pain syndrome and 24 normal subjects were studied. Pain threshold of the active pressure algometer [Pressure Threshold Meter] before and after the treatment with each one of the above mentioned modalities and placebo "sham ultrasound." The Index of Threshold Change [ITC] is defined as the ratio of post-treatment pain threshold to pre-treatment pain threshold. Results: In the control study, the normal subjects without any treatment had an average ITC value of 1.02 ± 0.06 based upon 48 measurements; the patients without any treatment had an average ITC value of 1.02 ± 0.07 [n = 21], and the patients treated with placebo had an average ITC value of 1.09 ± 0.18 [n = 16]. The average ITC values were 1.53 ± 0.32 [n = 17] from hydrocollator treatment; 1.41 ± 0.39 [n = 16] from ultrasound therapy; and 1.77 ± 0.40 [n = 16] from deep pressure massage therapy. The ITC value from treatment with any of the 4 modalities was significantly higher than the ITC of any of the 3 control groups [P < 0.05, 2-tailed ANOVA], however, there were no significant differences among the other 3 modalities. The ITC value from treatment with stretchtherapy [spray and stretch or massage, n = 35] was significant higher than [P < 0.05, 2-tailed ANOVA] that with thermotherapy [hydrocollator or ultrasound, n = 33]. Conclusion: It would appear that all 4 therapeutic modalities can be effectively applied for the treatment of myofascial pain syndrome to obtain an immediate increase of pain threshold of an active myofascial trigger point, although the stretch therapy is more effective than the thermotherapy.

KEYWORDS:

• Myofascial pain syndrome
• pressure algometer
• pain
• threshold
• thermotherapy
• ultrasound
• stretch
• massage