Tag: central lateral thalamotomy

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Bilateral focused ultrasound medial thalamotomies for trigeminal neuropathic pain: a randomized controlled study

J Neurosurg 140:1799–1809, 2024

Medial thalamotomy has been shown to benefit patients with neuropathic pain, but widespread adoption of this procedure has been limited by reporting of clinical outcomes in studies without a control group. This study aimed to minimize confounders associated with medial thalamotomy for treating chronic pain by using modern MRI-guided stereotactic lesioning and a rigorous clinical design.

METHODS This prospective, double-blinded, randomized controlled trial in 10 patients with trigeminal neuropathic pain used sham procedures as controls. Participants underwent assessments by a pain psychologist and pain management clinician, including use of the following measures: the Numeric Pain Rating Scale (NPRS); patient-reported outcome measures; and patient’s impression of improvement at baseline, 1 day, 1 week, 1 month, and 3 months postprocedure. Patients in the treated group underwent bilateral focused ultrasound (FUS) medial thalamotomy targeting the central lateral nucleus. Patients in the control group underwent sham procedures with energy output disabled. The primary efficacy outcome measure was between-group differences in pain intensity (using the NPRS) at baseline and at 3 months postprocedure. Adverse events were measured for safety and included MRI analysis. Exploratory measures of connectivity and metabolism were analyzed using diffusion tensor imaging, functional MRI, and PET, respectively.

RESULTS There were no serious complications from the FUS procedures. MRI confirmed bilateral medial thalamic ablations. There was no significant improvement in pain intensity from baseline to 3 months, either for patients undergoing FUS medial thalamotomy or for sham controls; and the between-group change in NPRS score as the primary efficacy outcome measure was not significantly different. Patient-reported outcome assessments demonstrated improvement (i.e., a decrease) only in pain interference with enjoyment of life at 3 months. There was a perception of benefit at 1 week, but only for patients treated with FUS and not for the sham cohort. Advanced neuroimaging showed that these medial thalamic lesions altered structural connectivity with the postcentral gyrus and demonstrated a trend toward hypometabolism in the insula and amygdala.

CONCLUSIONS This randomized controlled trial of bilateral FUS medial thalamotomy did not reduce the intensity of trigeminal neuropathic pain, although it should be noted that the ability to estimate the magnitude of treatment effects is limited by the small cohort.

Clinical trial registration no.: NCT03309813 (ClinicalTrials.gov)

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Transcranial magnetic resonance imaging–guided focused ultrasound: noninvasive central lateral thalamotomy for chronic neuropathic pain

Neurosurgical Focus Jan 2012 / Vol. 32 / No. 1 / Page E1. DOI: 10.3171/2011.10.FOCUS11248

Recent technological developments open the field of therapeutic application of focused ultrasound to the brain through the intact cranium. The goal of this study was to apply the new transcranial magnetic resonance imaging–guided focused ultrasound (tcMRgFUS) technology to perform noninvasive central lateral thalamotomies (CLTs) as a treatment for chronic neuropathic pain.

METHODS

In 12 patients suffering from chronic therapy-resistant neuropathic pain, tcMRgFUS CLT was proposed. In 11 patients, precisely localized thermal ablations of 3–4 mm in diameter were produced in the posterior part of the central lateral thalamic nucleus at peak temperatures between 51°C and 64°C with the aid of real-time patient monitoring and MR imaging and MR thermometry guidance. The treated neuropathic pain syndromes had peripheral (5 patients) or central (6 patients) origins and covered all body parts (face, arm, leg, trunk, and hemibody).

RESULTS

Patients experienced mean pain relief of 49% at the 3-month follow-up (9 patients) and 57% at the 1-year follow-up (8 patients). Mean improvement according to the visual analog scale amounted to 42% at 3 months and 41% at 1 year. Six patients experienced immediate and persisting somatosensory improvements. Somatosensory and vestibular clinical manifestations were always observed during sonication time because of ultrasound-based neuronal activation and/or initial therapeutic effects. Quantitative electroencephalography (EEG) showed a significant reduction in EEG spectral overactivities. Thermal ablation sites showed sharply delineated ellipsoidal thermolesions surrounded by short-lived vasogenic edema. Lesion reconstructions (18 lesions in 9 patients) demonstrated targeting precision within a millimeter for all 3 coordinates. There was 1 complication, a bleed in the target with ischemia in the motor thalamus, which led to the introduction of 2 safety measures, that is, the detection of a potential cavitation by a cavitation detector and the maintenance of sonication temperatures below 60°C.

CONCLUSIONS

The authors assert that tcMRgFUS represents a noninvasive, precise, and radiation-free neurosurgical technique for the treatment of neuropathic pain. The procedure avoids mechanical brain tissue shift and eliminates the risk of infection. The possibility of applying sonication thermal spots free from trajectory restrictions should allow one to optimize target coverage. The real-time continuous MR imaging and MR thermometry monitoring of targeting accuracy and thermal effects are major factors in optimizing precision, safety, and efficacy in an outpatient context.

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