Vascular Decompression in Trigeminal Neuralgia

Abstract

Early work by Dandy [3–6] and Gardner [7] concerning vascular compression and other abnormalities of the root entry zone of the trigeminal nerve form the basis for our current concepts of the etiology and definitive treatments of this disabling symptom called trigeminal neuralgia (TN). Dandy [3–6], starting in 1932, noted abnormalities of the dorsal root in a progressively larger percentage of his patients with TN. This innovative surgeon sectioned the portio major at the brainstem in these patients. He was able to treat TN without giving complete numbness by preserving fascicles which he described and called ‘accessory sensory fascicle’ during the nerve section. In the 5.6 percent of patients where an extra-axial tumor was the cause of the TN, he removed the lesion as treatment. He did not treat the TN by vascular decompression. Indeed, it was impressive that he was able to see vascular compression by ‘normal’ (although perhaps elongated) arteries and veins in 60 percent of the patients. Gardner [7] further elaborated upon abnormalities of the dorsal root of the trigeminal nerve and lucidly elaborated upon the pathophysiological mechanisms involved. Others more recently described gross lesions such as aneurysms, tumors and other abnormalities in the cerebellopontine angle of patients with TN. Despite these publications, there was little or no acceptance of this concept until recently. Many reasons for this lack of acceptance may be given: Some of them may include: relatively primitive technology, lack of verification by others, inadequate documentation of findings and rare definitive treatment. However, with the development of safer operative and anesthetic techniques for surgery of the cerebellopontine angle, the use of microsurgical techniques, photographic and videotape documentation of findings and definitive treatment, the concepts of root entry zone abnormality as the etiology of TN and microvascular decompression as therapy have had wide acceptance in recent years.