Influence of previous treatment on outcome after glycerol rhizotomy for trigeminal neuralgia.

The aim of the present study was to evaluate the influence of previous treatment on outcome and sensory disturbance after a retrogasserian glycerol injection for trigeminal neuralgia. Ninety-nine patients with trigeminal neuralgia underwent a retrogasserian glycerol rhizotomy. Fifty-three of those patients experienced recurrent pain after the previous treatment. At the 1 year follow-up, the outcome was excellent or good in 83% of patients with no previous treatment, compared with 60 and 75% in those patients with earlier glycerol injections or radiofrequency lesions, respectively. Quantitatively assessed, the sensory impairment was most pronounced in patients who had earlier radio-frequency lesions compared with patients not treated previously. The occurrence of dysesthesia was more frequent in patients who had been surgically treated earlier. A review of the literature showed that the concentration of the glycerol preparation used probably is of great importance in terms of pain relief and sensory sequelae.