Chronic Facial Pain: Trigeminal Neuralgia, Persistent Idiopathic Facial Pain, and Myofascial Pain Syndrome-An Evidence-Based Narrative Review and Etiological Hypothesis

Abstract

Trigeminal neuralgia (TN), the most common form of severe facial pain, may be confused with an ill-defined persistent idiopathic facial pain (PIFP). Facial pain is reviewed and a detailed discussion of TN and PIFP is presented. A possible cause for PIFP is proposed. (1) Methods: Databases were searched for articles related to facial pain, TN, and PIFP. Relevant articles were selected, and all systematic reviews and meta-analyses were included. (2) Discussion: The lifetime prevalence for TN is approximately 0.3% and for PIFP approximately 0.03%. TN is 15-20 times more common in persons with multiple sclerosis. Most cases of TN are caused by neurovascular compression, but a significant number are secondary to inflammation, tumor or trauma. The cause of PIFP remains unknown. Well-established TN treatment protocols include pharmacotherapy, neurotoxin denervation, peripheral nerve ablation, focused radiation, and microvascular decompression, with high rates of relief and varying degrees of adverse outcomes. No such protocols exist for PIFP. (3) Conclusion: PIFP may be confused with TN, but treatment possibilities differ greatly. Head and neck muscle myofascial pain syndrome is suggested as a possible cause of PIFP, a consideration that could open new approaches to treatment.

Keywords: chronic facial pain; myofascial pain syndrome; persistent idiopathic facial pain; trigeminal neuralgia.

Figure 1

The referred pain patterns of relevant neck and head muscles that refer pain to the face in the trigeminal nerve distribution. The names of the muscles whose referred pain pattens are shown are noted under each individual illustration. Note that the sternocleidomastoid muscle can refer to the side of face primarily in the distribution of the second division of the trigeminal nerve in addition to its more common referral over the eye in the distribution of the first division. Many of these muscles are associated with the function of the temporomandibular joint and may be activated in disorders of the joint as well as in situations of bruxism and of clenching. (Images from C Triggerpoints 3D, used with permission).