Surgical decompression of blood vessels impinging on the trigeminal root has been described for the treatment of trigeminal neuralgia 141. While the decompression procedure may alleviate symptoms, it is likely that the surgery has effects other than merely lifting free the vessel thought to be compressing. Evidence favoring this view is provided by studies of herpes simplex virus (HSV).It has been known for many years that trigeminal root section for the treatment of trigeminal neuralgia may result in activation of latent HSV in trigeminal ganglia 1.11. Latent HSV resides in neurons in the trigeminal ganglia [7]. During rhizotomy procedures, it is likely that root section or manipulation of trigeminal ganglion neurons results in the activation of latent ganglionic virus. This letter emphasizes that similar activation of latent HSV was frequently noted after vascular decompression of the trigeminal root for the treatment of trigeminal neuralgia 141.HSV activation is likely due to stimulation of or damage to trigeminal ganglion neurons, or both. Lessening of pain might be due to similar neuronal mechanisms rather than to decompression per se. For example, application of neurosurgical balloon technology can reduce the pain of trigeminal neuralgia 131. Others have also concluded that mechanical trauma or manipulation of the sensory root is important for the relief of trigeminal neuralgia 15, 61. Recently, percutaneous injection of the trigeminal cistern with glycerol has been reported to alleviate trigeminal neuralgia, and also may lead to the reactivation of HSV 121. These comments are not meant to detract from the reported improvement in pain after trigeminal root decompression but do suggest that removal of putative compressing vessels from nerve roots may not be the mechanism of improvement.
RefevenceJ1. Carton CA, Clbourne ED: Activation of latent herpes simplex by trigeminal sensory-root section. N Engl J Med 246:172-176, 1952 2. Lunsford LD, Bennett MH: Percutaneous retrogasserian glycerol rhizotomy for tic douloureux: part 1. Neurosurgery 14:424-429, 1084 3 . Mullen S, Duda EE, Patronas NJ: Some examples of balloon technology in neurosurgery. J Neurosurg 52:321-329, 1980 4. Pain GJ, Ho M, Jannetta PJ: Reactivation of herpes simplex virus after decompression of the trigeminal nerve root. J Infect Dis 138:405-409, 1978 5. Shelden CH, Pudenz RH, Freshwater DB, Crue BL Compression rather than decompression for trigeminal neuralgia. J Neurosurg 12: 123-126, 1955 6. Stender A, Grumme 7. Late results of gangliolysis as a treatmenf of trigeminal neuralgia. J Neurosurg 31:21-24, 1969 7. Tenser RB, Dawson M, Ressel SJ, Dunstan ME: Detection ol' herpes simplex virus mRNA in latently infected trigeminal ganglion neurons by in situ hybridization. Ann Neurol 11:285-291, 1982 T
--Although loss of consciousness is a well-recognized feature of basilar artery migraine [ l}, there are remarkably few accounts in which systematic clinical observations have been made and an electroencephalogram (EEG) has been recorded during such ...