The pathophysiology of trigeminal neuralgia, hemifacial spasm and other dis
orders that can be cured by microvascular decompression of cranial nerves,
is reviewed and different hypotheses about its pathophysiology are discusse
d. It is found that the pathophysiology of these disorders is complex and o
ther factors than vascular compression are necessary to cause symptoms. Whi
le the efficacy of the microvascular decompression (MVD) operation is indis
putable, it is questionable if the symptoms and signs of these disorders ar
e caused by abnormal neural activity in the respective cranial nerves that
result from the compression from a blood vessel. Instead, studies point to
hyperactivity and hyperexcitability of the respective nuclei as a cause of
the symptoms and signs of these disorders. Results of several studies indic
ate that irritation of the cranial nerve in question from close contact wit
h a blood vessel may promote such development, and it seems necessary that
other factors in addition to the vascular contact must be present in order
that such a condition develops.