MR-Guided Focused Ultrasound Central Lateral Thalamotomy for Trigeminal Neuralgia. Single Center Experience

Abstract

Background: Trigeminal neuralgia (TN) is a recognized pain condition the treatment of which can be very challenging. Various surgical interventions can be applied in cases of therapy-resistance to drug treatments. The central lateral thalamotomy (CLT) against neurogenic (or neuropathic) pain is based on multiarchitectonic histological as well as physiopathological studies, and integrates the nucleus in a large thalamocortical (TC) and corticocortical network responsible for the sensory, cognitive and affective/emotional components of pain. The advent of the magnetic resonance imaging guided high intensity focused ultrasound (MRgFUS) brought a strong reduction in morbidity and increase in accuracy compared to penetration techniques. Objective: This study was aimed at analyzing the outcome of bilateral MRgFUS CLT for chronic therapy-resistant trigeminal pain, all performed in one single center. Methods: Patients were categorized in Classical, Idiopathic and Secondary TN. By definition, paroxysms lasted for seconds up to 2 min. All patients were screened for trigeminal neurovascular conflict. In case of classical TN, microvascular decompression was proposed. Therapy-resistance and thus indication for MRgFUS CLT was based on the lack of efficacy and/or side effects of antiepileptic and antidepressant drugs. Good outcome was defined by a pain relief ≥50%. Results: Eight patients suffering from chronic therapy-resistant trigeminal neuralgia were treated. All suffered from pain with paroxysmal character. Six patients reported additionally continuous pain. Mean follow-up was 53 months (range: 12-92, median: 60 months). The mean pain relief assessed by patients was 51% (median: 58%, range: 0-90%) at 3 months, 71% (median: 65%, range: 40-100%) at 1 year and 78% (median: 75%, range: 50-100%) at their longest follow-up. This represents 63% good outcomes at 3 months, 88% at 1 year and 100% at last follow-up. Frequency of the mean pain paroxysms decreased from 84 per day preoperative to 3.9 at 1 year postoperatively. There were no serious adverse events in this series. Conclusion: Our study provides preliminary support for the safety and efficacy of MRgFUS CLT, a histologically and pathophysiologically based medial thalamotomy against chronic therapy-resistant trigeminal neuralgia.

Pre-operative Limbic System Functional Connectivity Distinguishes Responders From Non-responders to Surgical Treatment for Trigeminal Neuralgia

“…In turn, this would argue in favor of earlier surgical intervention in TN, which has been suggested to produce more durable pain relief ( 37 ). Furthermore, the functional networks identified in the present study may serve as potential pre-operative biomarkers of surgical outcome for TN and may also represent potential neurosurgical targets for TN or other pain conditions ( 38 – 40 ). We are currently carrying out further studies in which functional connectivity of the limbic system is compared between short-duration and longer-duration TN patients, and longitudinal studies in which functional connectivity is evaluated before and after TN surgery, in order to better understand the impact of limbic networks on treatment-resistance, the utility of limbic network connectivity as a biomarker of surgical outcome, and the extent to which altered limbic networks can actually be normalized by surgical intervention.…”

Focused Ultrasound in Neuroscience. State of the Art and Future Perspectives

“…Drug-resistant trigeminal neuralgia is a debilitating pain condition that often is treated by surgery. In such cases, recently, it has been shown that tcMRgFUS bilateral central-lateral thalamotomy effectively treats patients affected by drug-resistant trigeminal neuralgia, with 63% of good outcomes at three months, 88% at 1 year and 100% at last follow-up with no adverse events [ 40 ].…”

“…Regarding clinical applications of focused ultrasound, it has been recently demonstrated that tcMRgFUS postero-central lateral thalamotomy is an effective treatment of drug-resistant chronic neuropathic pain and trigeminal neuralgia [ 40 ]. In contrast, local MRgFUS ablation effectively treats pain related to lumbar bone metastases [ 43 , 44 ].…”

Neuroablative central lateral thalamotomy for chronic neuropathic pain

“…Another study conducted by Jeanmonod et al focused on the use of MRI-guided focused ultrasound CLT albiet more specifically for trigeminal neuralgia ( 41 ). Eight patients with a mean age of 62 ± 12 years and a mean symptom duration of 17 ± 12 years were treated.…”