The blink reflex before and after percutaneous glycerol rhizotomy in patients with trigeminal neuralgia--a prospective study of 28 patients.

The blink reflex was prospectively studied in 28 patients with trigeminal neuralgia, prior-to and following percutaneous glycerol rhizotomy to the Gasserian ganglion. Fifteen patients (54%) had varying degrees of sensory loss in the trigeminal nerve distribution already before glycerol injection. Three more patients developed sensory loss following glycerol injection. Thus following glycerol injection 18 patients had graded sensory loss. Pre-injection the blink reflex showed abnormal R1 wave in 57% patients, while direct and consensual R2 waves were abnormal in 43% and 48%, respectively. Post-injection R1 wave was abnormal in 64% patients. Direct R2 waves were abnormal in 33% patients. Thus clinical findings of sensory loss correlated well with pre-and post-injection blink reflex abnormality. Postoperatively R1 and ipsilateral R2 latencies from the side of the injection deteriorated and consensual R2 latency improved, thus, signifying better function on the contralateral side following relief of pain by glycerol rhizotomy.