Cervical plexus block helps in diagnosis of orofacial pain originating from cervical structures.

Headache associated with cervical lesions is called cervicogenic headache and involves the occiput but not the orofacial region. However, patients occasionally present with orofacial pain accompanied by neck symptoms. This study investigates whether orofacial pain can originate from the neck and whether cervical plexus block can help in diagnosis. We enrolled eight patients suffering from chronic orofacial pain that had not been relieved by dental treatment. Radiographic and magnetic resonance imaging revealed abnormal findings in the neck in seven of them. To identify the origin of the orofacial pain, we firstly blocked peripheral sensory input from the oral cavity and surrounding tissues, followed by that from deep cervical structures. We injected local anesthetics around the painful orofacial region, then to the tender points in the masticatory and superficial cervical muscles (trigger point injection), and consequently around the cervical plexus. Pain was assessed using a pain relief score compared with pre-treatment control values. Local anesthesia in the painful oral region provided insufficient relief whereas trigger point injection significantly relieved pain. The amount of pain relief generated by the deep cervical plexus block was more significant than that produced by any other procedures. We conclude that certain types of orofacial pain originate from cervical structures and that a deep cervical plexus block can be helpful in differentially diagnosing such pain.