The effect of local heating of trigger points on neck pain and plantar fascia pain

Background: Myofascial trigger points have been recognized for almost 100 years. They are commonly manipulated by dry needling or injections. Heat is associated with relaxation in muscle and increased tissue blood flow. Purpose: The purpose of this study was to examine the effect of single heat cells on trigger points to see if there was pain reduction in 2 areas of the body, the neck and plantar fascia. Methods: Forty adults in the age range between 20 and 64 participated in this study, and they were divided to 2 different groups according to their pain area; 20 had plantar foot pain due to plantar fasciitis and 20 had nonspecific neck pain for at least 1 month. Half of the subjects of each group were randomly divided into 2 subgroups and given either heat or a sham; 48 hours later subjects crossed over from one treatment to the other during the course of the trial. For each group (neck or plantar pain), 20 of the subjects were given a single heat patch on the trigger points for the neck or foot as appropriate and the other half a sham cell as a placebo. The subjects were tested for 4 hours. At the start, a visual analog pain scale was used and pressure pain threshold was measured with a pressure algometer. A stop watch was given to the subject and started as either the heat patch or placebo was applied to assess when pain starts relieved. R esults : A significant pain reduction was shown in both heat groups (both neck and plantar pain) (p 0.05). For significant pain relief, for the sham groups, over half of the subjects did not press the stop watches at all in the sham groups at the end. Both heat groups were not significantly different than each other and were significantly less in time than the sham groups (p < 0.01). Conclusions: There was a small placebo effect in the sham subgroups where some pain relief and ability to tolerate pressure were seen. But the effect of a heat for the neck and plantar areas of the body was significantly better in the heat groups than the sham groups. Recommendations: More areas of the body need to be tested and on repeated days to see the effect of local heating of trigger points on chronic pain.