Artikel
Evaluation of laser-evoked potentials and magnetoencephalography as a predictive value for patients with trigeminal neuralgia undergoing microvascular decompression
Evaluation der laser-evozierten Potentiale und der Magnetenzephalographie als prädiktive Faktoren für das Outcome der Patienten mit Trigeminusneuralgie nach der mikrovaskulären Dekompression
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Veröffentlicht: | 8. Mai 2019 |
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Objective: The most common cause of classic trigeminal neuralgia (TN) is a neurovascular conflict (NVC) of the trigeminal nerve in cerebellopontine angle. To this day, indications for MVD are made based on symptoms and clinical history since MRI doesn’t deliver specific information about NVC. So far, there are no further preoperative methods available to evaluate the existence and predictive relevance of NVCs and the success rate of MVD. Laser-evoked potentials (LEP) allow documentation of nociceptive pain conduction to the brain cortex, where brain activity is tracked with MEG. The aim of this study is to potentially find a pattern of nerve damage that favor or hinder therapeutic success of MVD.
Methods: Patients who were considered for MVD were included in this study. Pain was monitored using the visual analog scale (VAS) and Pain Detect Score. Patients received pre- and postoperative measurement of LEPs using a 122-channel whole head magnetoencephalogram (MEG), in the painful trigeminal dermatome and the corresponding contralateral dermatome. Time-frequency analyses and phase-coupling responses were conducted. Assessments were repeated 4 weeks after MVD treatment.
Results: N=4 patients were included in this study. All patients who were pain free according to VAS after successful MVD had both differences in the time-frequency analysis between pain side and control side prior to surgery as well as a change in latency after surgery on the pain side. Oscillatory responses to the laser stimuli showed reduced and delayed response on the pathologic side which post surgically normalized. One Non-Responder patient didn’t show any of alterations.
Conclusion: This is a step towards identifying and distinguishing responders from non-responders for MVD. Trigeminal LEPs may be an indicator for trigeminal nerve dysfunction and NVC in trigeminal neuralgia depending on the amplitude and latency shown in the analyses above. To evaluate the outcome of a surgical MVD treatment of TN patients qualitatively more patients need to be assessed in the future.