Factors Associated with Headache and Nausea During Magnetic Resonance-Guided Focused Ultrasound for Tremor

Scalp Nerve Block Alleviates Headaches Associated With Sonication During Transcranial Magnetic Resonance-Guided Focused Ultrasound

BACKGROUND AND OBJECTIVES

In magnetic resonance-guided focused ultrasound (MRgFUS) procedures, headache is a frequent symptom and cause of treatment discontinuation. Herein, we assessed the efficacy of scalp nerve block (SNB) for alleviating headache during MRgFUS procedures.

METHODS

The effect of SNB on intraprocedural headache was examined by retrospectively comparing 2 patient cohorts at a single institution. During the study period from April 2020 to February 2022, an SNB protocol for all patients with a skull density ratio ≤0.55 was instituted on October 6, 2021. The number of patients with a skull density ratio ≤0.55 was 34 before the protocol and 36 afterward. Headache intensity was evaluated using a numerical rating scale (NRS) after each sonication. To evaluate the effect of SNB on headache intensity, multiple regression analysis was performed per patient and per sonication. In the per-patient analysis, the effect of SNB was evaluated using the maximum NRS, mean NRS, and NRS at the first ultrasound exposure that reached 52.5°C. In the per-sonication analysis, the effect of SNB was evaluated not only for the entire sonication but also for sonications classified into ≤9999 J, 10 000 to 29 999 J, and ≥30 000 J energy doses.

RESULTS

With SNB, headache alleviation was observed in the NRS after the first sonication that reached 52.5°C in each patient (β = -2.40, 95% CI -4.05 to -0.758, P = .00499), in the NRS when all sonications were evaluated (β = -0.647, 95% CI -1.19 to -0.106, P = .0201), and in the NRS when all sonications were classified into 10 000 to 29 999 J (β = -1.83, 95% CI -3.17 to -0.485, P = .00889).

CONCLUSION

SNB significantly reduced headache intensity during MRgFUS, especially that caused by sonication with a moderate-energy dose. These findings suggest that scalp nerves play a role in headache mechanisms during MRgFUS.

Unilateral Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy Thalamotomy for Essential Tremor

BACKGROUND

Essential tremor (ET) affects numerous adults, impacting quality of life (QOL) and often defying pharmacological treatment. Surgical interventions like deep brain stimulation (DBS) and lesional approaches, including radiofrequency, gamma-knife radiosurgery, and magnetic resonance imaging (MRI)-guided focused ultrasound, offer solutions but are not devoid of limitations.

OBJECTIVES

This retrospective, single-center, single-blinded pilot study aimed to assess the safety and efficacy of unilateral MRI-guided laser interstitial thermal therapy (MRIg-LITT) thalamotomy for medically intractable ET.

METHODS

Nine patients with ET, unresponsive to medications and unsuitable for DBS, underwent unilateral MRIg-LITT thalamotomy. We assessed tremor severity, QOL, cognitive function, and adverse events (AE) over a 12-month period.

RESULTS

Tremor severity significantly improved, with a reduction of 83.37% at 12 months post-procedure. QOL scores improved by 74.60% at 12 months. Reported AEs predominantly included transient dysarthria, proprioceptive disturbances, and gait balance issues, which largely resolved within a month. At 3 months, 2 patients (22%) exhibited contralateral hemiparesis requiring physiotherapy, with 1 patient (11%) exhibiting persistent hemiparesis at 12 months. No significant cognitive impairment was detected post-procedure.

CONCLUSIONS

Unilateral MRIg-LITT thalamotomy yielded substantial and enduring tremor alleviation and enhanced QOL in patients with ET that is resistant to medication. The AE profile was acceptable. Our findings support the need for additional research with expanded patient cohorts and extended follow-up to corroborate these outcomes and to refine the role of MRIg-LITT as a targeted and minimally invasive approach for ET management. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Magnetic Resonance-Guided Focused Ultrasound (MRgFUS)-Thalamotomy for Essential Tremor: Lesion Location and Clinical Outcomes

BACKGROUND

Factors predicting clinical outcomes after MR-guided focused ultrasound (MRgFUS)-thalamotomy in patients with essential tremor (ET) are not well known.

OBJECTIVE

To examine the clinical outcomes and their relationship with patients' baseline demographic and clinical features and lesion characteristics at 6-month follow-up in ET patients.

METHODS

A total of 127 patients were prospectively evaluated at 1 (n = 122), 3 (n = 102), and 6 months (n = 78) after MRgFUS-thalamotomy. Magnetic resonance imaging (MRI) was obtained at 6 months (n = 60). Primary outcomes included: (1) change in the Clinical Rating Scale of Tremor (CRST)-A+B score in the treated hand and (2) frequency and severity of adverse events (AEs) at 6 months. Secondary outcomes included changes in all subitems of the CRST scale in the treated hand, CRST-C, axial tremor (face, head, voice, tongue), AEs, and correlation of primary outcomes at 6 months with lesion characteristics. Statistical analysis included linear mixed, standard, and logistic regression models.

RESULTS

Scores for CRST-A+B, CRST-A, CRST-B in the treated hand, CRST-C, and axial tremor were improved at each evaluation (P < 0.001). Five patients had severe AEs at 1 month that became mild throughout the follow-up. Mild AEs occurred in 71%, 45%, and 34% of patients at 1, 3, and 6 months, respectively. Lesion volume was associated with the reduction in the CRST-A (P = 0.003) and its overlapping with the ventralis intermedius nucleus (Vim) nucleus with the reduction in CRST-A+B (P = 0.02) and CRST-B (P = 0.008) at 6 months.

CONCLUSIONS

MRgFUS-thalamotomy improves hand and axial tremor in ET patients. Transient and mild AEs are frequent. Lesion volume and location are associated with tremor reduction. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Magnetic Resonance-Guided Focused Ultrasound without Anesthesiologist Support

INTRODUCTION

Magnetic resonance-guided focused ultrasound (MRgFUS) is an effective treatment option for essential tremor (ET) and tremor dominant Parkinson's disease (TDPD), which is often performed with sedation or in the presence of an anesthesiologist in an effort to minimize adverse events and maximize patient comfort. This study explores the safety, feasibility, and tolerability of performing MRgFUS without an anesthesiologist.

METHODS

This is a single academic center, retrospective review of 180 ET and TDPD patients who underwent MRgFUS treatment without anesthesiologist support. Patient demographics, intra-procedural treatment parameters, peri-procedural adverse events, and 3-month Clinical Rating Scale for Tremor Part B (CRST-B) scores were compared to MRgFUS studies that utilized varying degrees of anesthesia.

RESULTS

There were no anesthesia related adverse events or unsuccessful treatments. There were no early treatment terminations due to patient discomfort, regardless of skull density ratio. 94.6% of patients would repeat the procedure again. The most common side effects during treatment were facial/tongue paresthesia (26.3%), followed by nausea (22.3%), dysarthria (8.6%), and scalp pain (8.0%). No anxiolytic, pain, or antihypertensive medications were administered. The most common early adverse event after MRgFUS procedure was gait imbalance (58.3%). There was a significant reduction of 83.1% (83.4% ET and 80.5% TDPD) of the mean CRST-B scores of the treated hand when comparing 3-month and baseline scores (1.8 vs. 10.9, n = 109, p < 0.0001).

CONCLUSION

MRgFUS without intra-procedural anesthesiologist support is a safe, feasible, and well-tolerated option, without an increase in peri-procedural adverse events.

Magnetic resonance imaging-guided focused ultrasound thalamotomy launch with remote telemedicine international proctorship

Background

COVID-19 limitations have hindered the implementation of new technologies by preventing proctors from coming to the site. We share our first experience of magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) treatment with an international remote online proctorship, and develop and evaluate the methodology of remote MRgFUS proctorship.

Methods

This single-center, nonrandomized controlled prospective study included 94 patients: 27 with essential tremor (ET) and 67 with tremor-dominant Parkinson's disease (PD). The coming of proctors was impossible, so we arranged for the remote participation of proctors from the United Kingdom, Spain, and Israel. A total of 38 patients (40.4%) received telemedicine-proctored treatment (proctor group) and 56 received their treatment independently (solo group). We used the Clinical Rating Scale for Tremor (CRST) for ET patients and the Unified Parkinson's Disease Rating Scale (UPDRS) Part III for PD patients.

Results

In patients with ET, success rates were 81.8% (proctor group) and 100% (solo group) (p = 0.22). CRST reduction on the treated side was 71.43% [65.83%; 80.56%] (proctor group) versus 60.87% [53.99; 79.58] (solo group) (p = 0.19). None of the patients showed worsening of tremors within 1 year. In patients with PD, the success rates were 92.6% (proctor group) and 100% (solo group) (p = 0.08). The UPDRS Part III improvement was 30.1% (proctor group) versus 39.9% (solo group) (p = 0.003). The 1-year recurrence rate was 40% (proctor group) and 17.5% (solo group) (p = 0.04). No complications were observed at 6 months.

Conclusions

We developed a feasible and safe methodology for telemedicine remote online-proctored MRgFUS treatment. No significant difference was observed between the solo and developed remote proctor protocols in terms of complication rate, effect, and long-term results; however, UPDRS Part III improvement was better in the PD solo group. This study demonstrated that the MRgFUS international proctorship can be performed successfully remotely.

Characteristics of Pain During MRI-Guided Focused Ultrasound Thalamotomy

BACKGROUND

Magnetic resonance imaging-guided focused ultrasound (MRgFUS) has become popular as an incisionless mode of neurosurgical treatment. However, head pain during sonication is common and its pathophysiology remains poorly understood.

OBJECTIVE

To explore the characteristics of head pain occurring during MRgFUS thalamotomy.

METHODS

Our study comprised 59 patients who answered questions about the pain they experienced during unilateral MRgFUS thalamotomy. The location and features of pain were investigated using a questionnaire including the numerical rating scale (NRS) to estimate maximum pain intensity and the Japanese version of the Short Form of McGill Pain Questionnaire 2 to evaluate the quantitative and qualitative dimensions of pain. Several clinical factors were investigated for possible correlation with pain intensity.

RESULTS

Forty-eight patients (81%) reported sonication-related head pain, and the degree of pain was severe (NRS score ≥ 7) in 39 patients (66%). The distribution of sonication-related pain was "localized" in 29 (49%) and "diffuse" in 16 (27%); the most frequent location was the "occipital" region. The pain features most frequently reported were those in the "affective" subscale of the Short Form of McGill Pain Questionnaire 2. Patients with diffuse pain had a higher NRS score and lower skull density ratio than did patients with localized pain. The NRS score negatively correlated with tremor improvement at 6 months post-treatment.

CONCLUSION

Most patients in our cohort experienced pain during MRgFUS. The distribution and intensity of pain varied according to the skull density ratio, indicating that the pain might have had different origins. Our results may contribute to the improvement of pain management during MRgFUS.