Neurovascular compression of the greater occipital nerve: Implications for migraine headaches

Background: Surgical release of the greater occipital nerve has been demonstratedto be clinically effective in eliminating or reducing chronic migrainesymptoms. However, migraine symptoms in some patients continue after thisprocedure. It was theorized that a different relationship between the greateroccipital nerve and occipital artery may exist in these patients that may becontributing to these outcomes. A cadaveric investigation was performed in aneffort to further delineate the occipital artery- greater occipital nerve relationship.Methods: Fifty sides of 25 fresh cadaveric posterior necks and scalps weredissected. The greater occipital nerve was identified within the subcutaneoustissue and its relationship with the occipital artery was delineated. A topographicmap of the intersection of the two structures was created.Results: The greater occipital nerve and occipital artery have an intimate relationship,and crossed each other in 27 hemiheads (54.0 percent). The relationshipbetween these structures when they crossed varied from a single intersectionto a helical intertwining.Conclusions: The greater occipital nerve and occipital artery have an anatomicalintersection 54 percent of the time. There are two morphologic types ofrelationships between the structures: a single intersection point and a helicalintertwining. Vascular pulsation may cause irritation of the nerve and is apossible explanation for migraine headaches that have the occipital region asa trigger point. Future imaging studies and clinical investigation is necessary tofurther examine the link between anatomy and clinical presentation.