Introduction: MVD is ranked as the most effective remedy for TN. Nevertheless, not all patients can be completely cured by MVD, and recurrence or delayed relief may occur in a small proportion of patients. This dilemma reflects the lack of thorough understanding TN mechanisms, which are now considered a unique form of neuropathic pain and the most common type of neuralgia. This study was conducted to determine whether mechanical allodynia (MA) acts as a predictor of outcome after microvascular decompression (MVD) for trigeminal neuralgia (TN) and discuss the potential pathological mechanisms involved.
Methods: A series of 246 patients who underwent MVD for TN were involved in the study. The classifications were based on the characteristic of pain (shock-like or constant), and the presence of MA was defined from the chart review, retrospectively. The surgical outcome is defined as excellent, good, and poor. Immediate and long-term outcomes were compared to provide the information on recurrence and delayed relief. The relationship among the groups was investigated, and the strength was determined.
Results: Both presence of MA and type of TN pain are significant predictors of surgical outcome (P < 0.05). MA was proven to be an independent predictor of surgical outcome and also a significant predictor of existence of neurovascular compression (P < 0.05) and lower rate of recurrence (P < 0.05). No statistically significant predictors of delayed relief were detected in this study.
Conclusions: The presence of MA is a reliable predictor of immediate and long-term outcome after MVD for TN. Compared to the patients without MA, the incidence rate of intraoperative neurovascular compression (NVC) was higher in MA-positive patients, who were more likely to achieve a better outcome and lower rate of recurrence after MVD for TN. Application of the information in this study will be helpful in patient selection of MVD for TN.
Patient Care: Application of the information in this study will be helpful in patient selection of MVD for TN.
Learning Objectives: By the conclusion of this session, participants should be able to:1)describe the importance of mechanical allodynia in predicting the surgical outcome of trigeminal neuralgia;2)discuss the relative mechanism involved in trigeminal neuralgia based on the recent progress in basic research on pain.