Characteristics of referred muscle pain to the head from active trigger points in women with myofascial temporomandibular pain and fibromyalgia syndrome

Cristina Alonso-Blanco,Fernando Galán-Del-Río,Pedro Zarco-Moreno,Peter Svensson,César Fernández-De-Las-Peñas,Ana Isabel De-La-Llave-Rincón

doi:10.1007/s10194-012-0477-y

Abstract

Our aim was to compare the differences in the prevalence and the anatomical localization of referred pain areas of active trigger points (TrPs) between women with myofascial temporomandibular disorder (TMD) or fibromyalgia (FMS). Twenty women (age 46 ± 8 years) with TMD and 20 (age 48 ± 6 years) with FMS were recruited from specialized clinic. Bilateral temporalis, masseter, sternocleidomastoid, upper trapezius, and suboccipital muscles were examined for TrPs. TrPs were identified by palpation and considered active when the pain reproduced familiar pain symptom experienced by the patient. The referred pain areas were drawn on anatomical maps, digitalized and also measured. A new analysis technique based on a center of gravity (COG) method was used to quantitative estimate of the localization of the TrP referred pain areas. Women with FMS exhibited larger areas of usual pain symptoms than women with myofascial TMD (P < 0.001). The COG coordinates of the usual pain on the frontal and posterior pain maps were located more superior in TMD than in FMS. The number of active TrPs was significantly higher in TMD (mean ± SD 6 ± 1) than in FMS (4 ± 1) (P = 0.002). Women with TMD exhibited more active TrPs in the temporalis and masseter muscles than FMS (P < 0.01). Women with FMS had larger referred pain areas than those with TMD for sternocleidomastoid and suboccipital muscles (P < 0.001). Significant differences within COG coordinates of TrP referred pain areas were found in TMD, the referred pain was more pronounced in the orofacial region, whereas the referred pain in FMS was more pronounced in the cervical spine. This study showed that the referred pain elicited from active TrPs shared similar patterns as usual pain symptoms in women with TMD or FMS, but that distinct differences in TrP prevalence and location of the referred pain areas could be observed. Differences in location of referred pain areas may help clinicians to determine the most relevant TrPs for each pain syndrome in spite of overlaps in pain areas.

Highlights

Temporomandibular (TMD) pain is a musculoskeletal local pain condition with a prevalence rate between 3 and 15 %, an incidence rate between 2 and 4 % [1] and a women–men ratio 2:1 [2]
This study showed that the referred pain elicited from active trigger points (TrPs) shared similar patterns as usual pain symptoms in women with temporomandibular disorder (TMD) or FMS, but that distinct differences in TrP prevalence and location of the referred pain areas could be observed
This study revealed that the referred pain elicited from active TrPs in head and neck–shoulder musculature reproduced the pain pattern in the orofacial region in women with myofascial TMD or FMS

Summary

Introduction

Temporomandibular (TMD) pain is a musculoskeletal local pain condition with a prevalence rate between 3 and 15 %, an incidence rate between 2 and 4 % [1] and a women–men ratio 2:1 [2]. Fibromyalgia (FMS) is a widespread diffuse musculoskeletal pain condition with a prevalence ranging from 0.5 % to 5.0 and a higher proportion of women [3, 4]. TMD pain has been frequently diagnosed on fibromyalgia subjects [5, 6] whereas the presence of widespread pain has been shown to be a significant risk factor for myofascial TMD [7]. A recent study has found an increased risk for the onset of clinically significant TMD pain when subjects had FMS [8]. It seems that TMD and FMS may share some patho-physiological mechanisms

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