Glycerol Rhizotomy as a Treatment Modality for Trigeminal Neuralgia

History of Glycerol Rhizotomy

Like many paramount medical treatments, the discovery of glycerol’s neurolytic effects and potential therapeutic application in TN was made by chance. During the 1970s in Stockholm, stereotactic gamma knife radiation was used in an attempt to ablate the trigeminal (gasserian) ganglion and dull pain signals in TN patients. Both glycerol and metrizamide were trialed as carriers of tantalum dust—a radiopaque material—that was injected to the trigeminal cistern as a visual waypoint for stereotactic calculations (Håkanson & Leksell, 1979). Glycerol became the medium of choice because of its documented role in human triglyceride synthesis, favorable viscosity, and prior use as a vehicle for phenol neurolysis, which was the predominant percutaneous TN treatment of the time (Jefferson, 1963). Håkanson and colleagues began to notice that injection of the medium alone appeared to relieve facial pain before the radio-ablative procedure was set to take place. The group subsequently outlined a method for the direct injection of glycerol into the trigeminal cistern and published the first case series in 1981 (Håkanson, 1981).