Reactivation of herpes simplex virus after decompression of the trigeminal nerve root.

Reactivation of herpes simplex virus was prospectively studied in patients after microneurosurgical decompression of the trigeminal sensory root, a new operation for trigeminal neuralgia in which the nerve is not sectioned. Reactivation was detected in 28 (50%) of 56 patients. Virus was cultured from oropharyngeal secretions in 25 patients, and 21 patients developed cutaneous herpetic lesions. Seven patients had positive throat-wash (TW) cultures but did not develop lesions, and the converse occurred in three patients. Eighteen patients had both positive TW cultures and herpetic lesions. In eight of nine instances in which a sequence was determinable, TW cultures were positive before lesions developed. A history of recurrent herpes labialis was associated with a higher risk of developing reactivation postoperatively (59.4% vs. 31.6%, P less than 0.05). These observations suggest that minimal stimulation or inapparent trauma to the trigeminal sensory root is sufficient to activate latent herpes simplex virus in humans. These patients provide unique opportunities to study immunologic responses and therapeutic measures.