Hemifacial Trigeminal Pain Referred from Occipital Neuralgia Due to Compression of the Greater Occipital Nerve by the Occipital Artery

Abstract

Although pathologic vascular contact between the occipital artery and the greater occipital nerve (GON) at the crossing point in the nuchal subcutaneous layer can cause occipital neuralgia, referred hemifacial trigeminal pain from chronic occipital neuralgia owing to this cause is extremely rare.A 61-year-old female patient with left-sided occipital neuralgia for 4 years presented with a new onset of left-sided hemifacial pain. Decompression of the left GON from pathologic contacts with the occipital artery resulted in immediate relief for hemifacial pain and chronic occipital neuralgia. The present case implies that sensitization and hyperactivity of the trigeminocervical complex that receives the convergent input from trigeminal and high cervical occipital nociceptive pathways can be a pathogenic mechanism in referred hemifacial pain from occipital neuralgia. In the present case, a branching tributary of the occipital artery at the crossing point forming a constricting loop above the course of the GON was found to be the cause of entrapment. Because the occipital artery is reported to be consistently located superficial to the GON at the crossing point, a spatial relationship between the occipital artery and the GON rather than a mere adhesion or contact might have pathologic significance in the development of occipital neuralgia.

Evaluating the Evidence: Is Neurolysis or Neurectomy a Better Treatment for Occipital Neuralgia?

“…In 2017, Ko et al reported a case of hemifacial trigeminal pain referred from ON due to compression of the greater occipital nerve by the occipital artery [13]. The occipital artery was superficial to the greater occipital nerve, creating a crossing point and a constricting vascular loop.…”

Chronic Craniofacial Pain from Entrapment of the Greater Occipital Nerve Misdiagnosed as Chronic Migraine, Idiopathic Odontalgia, and Atypical Facial Pain

“…Clinical significance of the GON entrapment at and around the trapezial canal has been stressed repetitively during the last two decades. It is a well known etiology of occipital neuralgia 8,11,14,17,18) . In addition, entrapment of the GON was reported to be associated with cervicogenic headache, migraine headache 12) , chronic headache 6) , and referred trigeminal pain from occipital neuralgia 8,11,14) .…”

“…This prediction can be judged to be credible as the patient's symptoms have improved through decompression of the GON. We have experienced several cases that hemifacial pain, in addition to the occipital neuralgia, is improved by decompression of the GON 8,9,11,14,15) . Although it has already been mentioned that the pain of occipital neuralgia may be referred to the fronto-orbital area through trigeminocervical interneuronal connections in the trigeminal spinal nuclei 1) , referred facial pain in addition to occipital neuralgia has not been accurately reported 8,9,11,14,15) .…”

“…Many patients with craniofacial pain caused by chronic entrapment of the GON have been treated under multiple diagnoses such as migraine, tension headache, atypical facial pain, odontalgia, periorbital pain, and pain from temporomandibular joint disorders. We have demonstrated several cases regarding hemifacial, trigeminal referred pain from chronic GON entrapment 8,9,11,14,15) . Without knowledge and information on trigeminal referred facial pain from GON entrapment, many patients are still suffering from long-term ineffective treatment.…”

“…Occipital neuralgia is not a sole manifestation of compression/ entrapment of the GON. We experienced diverse presentations of craniofacial pain, in addition to paroxysmal stabbing pain of occipital neuralgia from compression/entrapment of the GON during the last 3 years 8,9,11,14,15) . From our positive experience of more than 100 cases of GON decompression, we have realized that constant aching pain, in addition to paroxysmal stabbing pain, are also common in GON entrapment.…”