[Temporomandibular disorder and cervicalgia: pathophysiology underlying the comorbidity with chronic migraine]

To analyze the prevalence of various clinical forms of temporomandibular disorder (TMD) and cervicalgia in episodic (EM) and chronic migraine (CM).

Ninety patients with CM and 42 patients with EM as defined by the International Classification of Headache Disorders (ICHD)-3 beta were recruited. TMD and sleep bruxism were diagnosed according to the DC/TMD criteria and the International Classification of Sleep Disorders (ICSD-R), respectively.

Myofascial pain was the most prevalent form of TMD in both EM and CM. The prevalence of TMD was higher in CM as compared to EM (60% vs. 21.4%, respectively, p=0.0001). The prevalence of bruxism was comparable across EM and CM (14.3% vs. 28.8%, respectively, p=0.08) and significantly lower than that of TMD in the CM population (28.8% vs. 60%, respectively, p=0.0001). Frequent cervicalgia (≥15 days per month) was reported by 65.5% and 21.4% of CM and EM patients, respectively (p=0.0001); 44.4% of CM patients reported neck pain immediately before or during migraine attacks only, 14.4% during the headache and interictal phases.

The higher prevalence of pain-related TMD and cervicalgia in CM population compared to EM and the general population was shown. In CM, myofascial pain and tenderness in the masticatory and neck muscles may be caused by central sensitization (CS) with no link to temporomandibular joint or spinal pathology. Myofascial TMD and neck muscle dysfunction are an integral part of CM pathophysiology underlying headache chronification.