title: Occipital artery vasculitis not identified as a mechanism of occipital neuralgia-related chronic migraine headaches.
abstract: BACKGROUND
  Recent evidence has shown that some cases of occipital neuralgia are attributable to musculofascial compression of the greater occipital nerve and improve with neurolysis. A mechanical interaction at the intersection of the nerve and the occipital artery may also be capable of producing neuralgia, although that mechanism remains one theoretical possibility among several. The authors evaluated the possibility of unrecognized vasculitis of the occipital artery as a potential mechanism of occipital neuralgia arising from the occipital artery/greater occipital nerve junction.
  
  
  METHODS
  Twenty-five patients with preoperatively documented bilateral occipital neuralgia-related chronic headaches underwent peripheral nerve surgery with decompression of the greater occipital nerve bilaterally, including the area of its intersection with the occipital artery. In 15 patients, a 2-cm segment of the occipital artery was excised and submitted for pathologic evaluation. All patients were evaluated intraoperatively for evidence of arterially mediated greater occipital nerve compression, and the configuration of the nerve-vessel intersection was noted.
  
  
  RESULTS
  None of the 15 specimens submitted for pathologic evaluation showed vasculitis. Intraoperatively, all 50 sites examined showed an intimate physical association between the occipital artery and greater occipital nerve.
  
  
  CONCLUSIONS
  Surgical specimens from this first in vivo study provided no histologic evidence of vasculitis as a cause of greater occipital nerve irritation at the occipital artery/greater occipital nerve junction in patients with chronic headaches caused by occipital neuralgia. Based on these findings, mechanical (and not primary inflammatory) irritation of the nerve by the occipital artery remains an important theoretical cause for otherwise idiopathic cases. The authors have adopted an operative technique that includes physical separation of the nerve-artery intersection (in addition to musculofascial neurolysis) for a more thorough surgical treatment of occipital neuralgia.
  
  
  METHODS
  Therapeutic, IV.
authors.affiliation: Washington, D.C.; and Dallas, Texas From the Department of Plastic Surgery, Peripheral Nerve Surgery Institute, Georgetown University Hospital, and the Department of Plastic Surgery, University of Texas Southwestern Medical Center.
authors.forename: Ivica
authors.initials: I
authors.lastname: Ducic
authors.forename: John M
authors.initials: JM
authors.lastname: Felder
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Janis
mesh_terms: D015331:Cohort Studies; D005500:Follow-Up Studies; D020773:Headache Disorders / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008881:Migraine Disorders / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D009437:Neuralgia / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods; D009777:Occipital Bone / Q000098:blood supply* / Q000294:innervation; D011300:Preoperative Care / Q000379:methods; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014657:Vasculitis / Q000150:complications / Q000175:diagnosis*