Evaluation of the New Classification of Trigeminal Neuralgia with a Retrospective Analysis

Introduction: The American Academy of Neurology classification for Trigeminal Neuralgia published in 2016 has certain advantages in comparison to previous ones; one of those advantages is that it correctly differentiates etiology from clinical presentation as categories for classification.

Nevertheless, there are some concerns related to the application of this classification and the correct management of patients with trigeminal neuralgia as it would appear that it limits the treatment possibilities for patients with refractory pain, particularly those with neurovascular compression of the trigeminal nerve that is not apparent on MRI.

Our study aimed to evaluate the accuracy and reliability of the classification by reviewing all the cases of trigeminal neuralgia attended at our center and grouping the patients using this classification to compare their final outcome in accordance to the treatment received.

Methods: All cases of trigeminal neuralgia seen at our center from January 2010 until May 2017 were included. Only the cases that were treated at our clinic were included in the analysis. Cases were classified using the new classification. Those that classified as secondary and idiopathic trigeminal neuralgia that were eventually treated with microvascular decompression and in which evidence of neurovascular contact was found during surgery were selected. Treatment and outcome of the patients was analyzed. Clinical presentation was divided into purely paroxysmal or with continuous pain. Follow-up of patients was done in average for 6 months after treatment. Clinical outcome was categorized as pain relief, recurrence, or persistence of pain during the follow-up.

Results: Of the 1,288 cases seen at our clinic, 851 were included. Classic trigeminal neuralgia (n = 660), secondary trigeminal neuralgia (n = 174), idiopathic trigeminal neuralgia (n = 17), purely paroxysmal (n = 802), continuous pain (n = 49). Nineteen patients classified as secondary trigeminal neuralgia were eventually treated with MVD. The reason to try surgery was based on a poor quality of life and refractoriness of pain to other treatments. All of these patients had pain relief after surgery.

Conclusion: The new classification for trigeminal neuralgia must be used carefully. By using it in our analysis, 11% of the patients would have ended up being denied a life changing surgery. Even though a patient has a concomitant neurological disease on clinical examination or MRI it does exclude the possibility he or she may present neurovascular contact of the trigeminal nerve and benefit from MVD.

No conflict of interest has been declared by the author(s).