Association Between Radiofrequency Rhizotomy Parameters and Duration of Pain Relief in Trigeminal Neuralgia Patients with Recurrent Pain

Background: Radiofrequency rhizotomy (RFR) is a commonly used, effective procedure for trigeminal neuralgia (TN), but a subset of patients experiences pain recurrence and requires subsequent surgeries. Currently, the rhizotomy temperature and duration of application are empirically determined, and there is no consensus on what settings are most beneficial. In this study, we analyzed patients who underwent trigeminal RFR and had subsequent surgeries to identify whether rhizotomy parameters were associated with the duration of pain relief. Methods: Single-center, retrospective analysis of patients undergoing RFR for TN from 1995 to 2016. The primary endpoint was subsequent procedure. Associations with rhizotomy parameters and covariates were assessed using Cox regression analysis. Results: The study included 338 patients, average age 65 years; 61% were women. Temperature was significantly associated with both the degree of immediate postoperative pain relief and the duration of pain relief, and in subgroup analyses by multiple sclerosis status and RFR procedural count. Ablation duration was also independently significant, though not when analyzed alongside age, sex, and race. Duration of pain relief was generally shorter in patients with multiple sclerosis and in repeated RFR. Conclusions: Higher temperatures may be necessary to achieve pain relief in some patients, given the progressive nature of the facial pain, but they are not associated with longer duration of pain relief in patients who have recurrent pain. Modulation of the ablation duration does not seem to affect the short-term or long-term outcomes.