Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound thalamotomy for essential tremor

Magnetic resonance guided focused ultrasound is a minimally invasive surgical procedure for symptomatic treatment of Parkinson Disease. With this technology, the ventral intermediate nucleusSTN, and internal globus pallidus have been targeted for therapeutic cerebral ablation, while also minimizing the risk of hemorrhage and infection from more invasive neurosurgical procedures.

In a pilot study published in 2013, essential tremor improved in 15 patients treated with magnetic resonance guided focused ultrasound thalamotomy1).

Clinical trials have confirmed the efficacy of focused ultrasound (FUS) thalamotomy in essential tremor, but its effectiveness and safety for managing tremor-dominant Parkinson disease (TDPD) is unknown.

It might change the way that patients with essential tremor and potentially other disorders are treated 2).

The post-treatment effectiveness was evaluated using the clinical rating scale for tremors. Thalamic MRgHIFU had substantial therapeutic effects on patients, based on MRgHIFU-mediated improvements in movement control and significant changes in brain mu rhythms. Ultrasonic thalamotomy may reduce hyper-excitable activity in the motor cortex, resulting in normalized behavioral activity after sonication treatment. Thus, non-invasive and spatially accurate MRgHIFU technology can serve as a potent therapeutic tool with broad clinical applications 3).

Magnetic resonance guided focused ultrasound (MRgFUS) for thalamotomy is a safe, effective and less-invasive surgical method for treating medication-refractory essential tremor (ET). However, several issues must be resolved before clinical application of MRgFUS, including optimal patient selection and management of patients during treatment 4).

Jung et al. found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise 5).

In a large academic medical center in the mid-Atlantic region, the Department of Neurosurgery conducted a continued access study, recently approved by the Food and Drug Administration, to evaluate the effectiveness of transcranial FUS thalamotomy for the treatment of medication-refractory ET.

One patient’s experience will be introduced, including discussion of evidence-based treatment options for ET and information on the nursing management of the patient undergoing FUS thalamotomy 6).

A PubMed search was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if hand tremor scores (HTS), total Clinical Rating Scale for Tremor (CRST) scores, or Quality of Life in Essential Tremor Questionnaire (QUEST) scores at regular intervals following MRgFUS treatment for essential tremor were documented. Data analyses included a random effects model of meta-analysis and mixed-effects model of meta-regression. Twenty-one articles reporting HTS for 395 patients were included. Mean pre-operative HTS was 19.2 ± 5.0. Mean HTS at 3 months post-treatment was 7.4 ± 5.0 (61.5% improvement, p < 0.001). Treatment effect was mildly decreased at 36 months at 9.1 ± 5.4 (8.8% reduction). Meta-regression of time since treatment as a modifier of HTS revealed a downward trend in effect size, though this was not statistically significant (p = 0.208). Only 4 studies included follow-up ≥ 24 months. Thirteen included articles reported total CRST scores with standardized follow-up for 250 patients. Mean pre-operative total CRST score decreased by 46.2% at 3 months post-treatment (p < 0.001). Additionally, mean QUEST scores at 3 months post-treatment significantly improved compared to baseline (p < 0.001). HTS is significantly improved from baseline ≥ 24 months post-treatment and possibly ≥ 48 months post-treatment. There is a current paucity of long-term CRST and QUEST score reporting in the literature 7).

In a double-blinded, prospective, sham-controlled randomized controlled trial of MR-guided focused ultrasound thalamotomy for treatment of tremor-dominant PD, 62% of treated patients demonstrated improvement in tremor scores from baseline to 3 months postoperatively, as compared to 22% in the sham group. There has been only one open-label trial of MR-guided focused ultrasound subthalamotomy for patients with PD, demonstrating improvements of 71% for rigidity, 36% for akinesia, and 77% for tremor 6 months after treatment. Among the two open-label trials of MR-guided focused ultrasound pallidotomy for patients with PD, dyskinesia and overall motor scores improved up to 52% and 45% at 6 months postoperatively. Although MR-guided focused ultrasound thalamotomy is now approved by the U.S. Food and Drug Administration for treatment of parkinsonian tremor, additional high-quality randomized controlled trials are warranted and are underway to determine the safety and efficacy of MR-guided focused ultrasound subthalamotomy and pallidotomy for treatment of the cardinal features of PD. These studies will be paramount to aid clinicians to determine the ideal ablative target for individual patients. Additional work will be required to assess the durability of MR-guided focused ultrasound lesions, ideal timing of MR-guided focused ultrasound ablation in the course of PD, and the safety of performing bilateral lesions 8).

see Magnetic resonance guided focused ultrasound thalamotomy for essential tremor case series.

De Vloo et al. reported on an ET patient who underwent an Magnetic resonance guided focused ultrasound thalamotomy but experienced tremor recurrence. They expanded the MRgFUS-induced thalamic cavity using radiofrequency (RF), with good effect on the tremor but transient sensorimotor deficits and permanent ataxia. This is the first report of a patient undergoing RF thalamotomy after an unsuccessful MRgFUS thalamotomy. As they used microelectrode recording to guide the RF thalamotomy, they could also study for the first time the electrophysiological properties of previously sonicated thalamic neurons bordering the MRgFUS-induced cavity. These neurons displayed electrophysiological characteristics identical to those recorded from nonsonicated thalamic cells in ET patients. Hence, this findings support the widespread assumption that sonication below the necrotic threshold does not permanently alter neuronal function 9).



1)

Elias WJ, Huss D, Voss T, Loomba J, Khaled M, Zadicario E, Frysinger RC, Sperling SA, Wylie S, Monteith SJ, Druzgal J, Shah BB, Harrison M, Wintermark M. A pilot study of focused ultrasound thalamotomy for essential tremor. N Engl J Med. 2013 Aug 15;369(7):640-8. doi: 10.1056/NEJMoa1300962. PubMed PMID: 23944301.
2)

Lipsman N, Schwartz ML, Huang Y, Lee L, Sankar T, Chapman M, Hynynen K, Lozano AM. MR-guided focused ultrasound thalamotomy for essential tremor: a proof-of-concept study. Lancet Neurol. 2013 May;12(5):462-8. doi: 10.1016/S1474-4422(13)70048-6. Epub 2013 Mar 21. PubMed PMID: 23523144.
3)

Chang JW, Min BK, Kim BS, Chang WS, Lee YH. Neurophysiologic correlates of sonication treatment in patients with essential tremor. Ultrasound Med Biol. 2015 Jan;41(1):124-31. doi: 10.1016/j.ultrasmedbio.2014.08.008. Epub 2014 Oct 22. PubMed PMID: 25438838.
4)

Chang WS, Jung HH, Kweon EJ, Zadicario E, Rachmilevitch I, Chang JW. Unilateral magnetic resonance guided focused ultrasound thalamotomy for essential tremor: practices and clinicoradiological outcomes. J Neurol Neurosurg Psychiatry. 2015 Mar;86(3):257-64. doi: 10.1136/jnnp-2014-307642. Epub 2014 May 29. PubMed PMID: 24876191.
5)

Jung HH, Chang WS, Rachmilevitch I, Tlusty T, Zadicario E, Chang JW. Different magnetic resonance imaging patterns after transcranial magnetic resonance-guided focused ultrasound of the ventral intermediate nucleus of the thalamus and anterior limb of the internal capsule in patients with essential tremor or obsessive-compulsive disorder. J Neurosurg. 2015 Jan;122(1):162-8. doi: 10.3171/2014.8.JNS132603. PubMed PMID: 25343176.
6)

Shaw KD, Johnston AS, Rush-Evans S, Prather S, Maynard K. Nursing Management of the Patient Undergoing Focused Ultrasound: A New Treatment Option for Essential Tremor. J Neurosci Nurs. 2017 Aug 16. doi: 10.1097/JNN.0000000000000301. [Epub ahead of print] PubMed PMID: 28817495.
7)

Miller WK, Becker KN, Caras AJ, Mansour TR, Mays MT, Rashid M, Schwalb J. Magnetic resonance-guided focused ultrasound treatment for essential tremor shows sustained efficacy: a meta-analysis. Neurosurg Rev. 2021 May 12. doi: 10.1007/s10143-021-01562-w. Epub ahead of print. PMID: 33978922.
8)

Moosa S, Martínez-Fernández R, Elias WJ, Del Alamo M, Eisenberg HM, Fishman PS. The role of high-intensity focused ultrasound as a symptomatic treatment for Parkinson’s disease. Mov Disord. 2019 Jul 10. doi: 10.1002/mds.27779. [Epub ahead of print] Review. PubMed PMID: 31291491.
9)

De Vloo P, Milosevic L, Gramer RM, et al. Microelectrode Recording and Radiofrequency Thalamotomy following Focused Ultrasound Thalamotomy [published online ahead of print, 2020 Sep 16]. Stereotact Funct Neurosurg. 2020;1-4. doi:10.1159/000510109

Idiopathic normal pressure hydrocephalus

Microvascular decompression for trigeminal neuralgia

Microvascular decompression for trigeminal neuralgia


Microvascular decompression is a first-line neurosurgical approach for classical trigeminal neuralgia with neurovascular conflict, but can show clinical relapse despite proper decompression. Second-line destructive techniques like radiofrequency thermocoagulation have become reluctantly used due to their potential for irreversible side effects. Subcutaneous peripheral nerve field stimulation (sPNFS) is a minimally invasive neuromodulatory technique which has been shown to be effective for chronic localised pain conditions.

The most frequently used surgical management of trigeminal neuralgia is Microvascular decompression (MVD), followed closely by stereotactic radiosurgery (SRS). Percutaneous stereotactic rhizotomy (PSR) , despite being the most cost-effective, is by far the least utilized treatment modality 1).

Microvascular decompression (MVD) via lateral suboccipital approach is the standard surgical intervention for trigeminal neuralgia treatment.

Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates 2)

Although microvascular decompression (MVD) is the most effective long-term operative treatment for TN, its use in older patient populations has been debated due to its invasive nature. The symptoms and surgical findings presented in a cohort for young-onset TN are similar to those reported in elderly adults. MVD appears to be a safe and effective treatment for young patients with TN 3).

see Microvascular decompression for trigeminal neuralgia and multiple sclerosis

see Awake Microvascular Decompression for Trigeminal Neuralgia.

see also Endoscope assisted microvascular decompression for trigeminal neuralgia.


Compared with the standard microscope-assisted techniques, the 3D exoscopic endoscope-assisted MVD offers an improved visualisation without compromising the field of view within and outside the surgical field 4).

97 patients with primary trigeminal neuralgia (PTN) underwent fully endoscopic microvascular decompression (MVD) via keyhole approach in Capital Medical University Affiliated Beijing Shijitan Hospital from December 2014 to February 2019 was collected. During fully endoscopic MVD in PTN via keyhole approach, performer use natural clearance without grinding except developed rock bone crest or excessive retraction of the brain tissue, visually and panoramically observe and evaluate the CPA area, accurately identify the responsible vessels, to avoid the omission of responsible vessels or insufficient decompression. And the use of preplaced technology, bridging technology and submersible technology, ensure the efficacy of surgery and reduce the surgical side injuries. Barrow Neurological Institute Pain Intensity Score was used to evaluate the efficacy and identify the recurrence. The surgical efficacy was analyzed. The offending vessels were identified under endoscope in 96 cases. Among them, arterial compression was found in 77 cases, venous compression in 6 cases, and both arterial and venous compression in 13 cases. About the pain outcomes, 87 cases had immediate and complete relief of pain, 5 cases had almost relief of pain, 4 cases had partial relief of pain, and still needed medication control, but the dose was lower than that before operation, and 1 case had no obvious relief of pain. About complications, there were 4 cases of temporary facial numbness, 1 case of temporary hearing loss, both of them recovered after symptomatic treatment. There was no cerebral infarction or hemorrhage, intracranial or incision infection. All cases were followed up for 3.0-38.0 months with a median period of(22.4±2.2) months. During the follow-up periods, postoperative recurrence occurred in 3 cases. Fully endoscopic MVD for PTN through keyhole approach, provides panoramic view to avoid omission of offending vessels and reduce complications, seemed to be a safe and effective surgical method 5).

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, PubMedCochrane Library, and Scopus were queried for primary studies examining pain outcomes after MVD for TN published between 1988 and March 2018. Potential biases were assessed for included studies. Pain freedom (ie, Barrow Neurological Institute score of 1) at last follow-up was the primary outcome measure. Variables associated with pain freedom on preliminary analysis underwent formal meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for possible predictors.

Outcome data were analyzed for 3897 patients from 46 studies (7 prospective, 39 retrospective). Overall, 76.0% of patients achieved pain freedom after MVD with a mean follow-up of 1.7 ± 1.3 (standard deviation) yr. Predictors of pain freedom on meta-analysis using random effects models included (1) disease duration ≤5 yr (OR = 2.06, 95% CI = 1.08-3.95); (2) arterial compression over venous or other (OR = 3.35, 95% CI = 1.91-5.88); (3) superior cerebellar artery involvement (OR = 2.02, 95% CI = 1.02-4.03), and (4) type 1 Burchiel classification (OR = 2.49, 95% CI = 1.32-4.67).

Approximately three-quarters of patients with drug-resistant TN achieve pain freedom after MVD. Shorter disease duration, arterial compression, and type 1 Burchiel classification may predict a more favorable outcome. These results may improve patient selection and provider expectations 6).

Microvascular decompression for trigeminal neuralgia technique.

Microvascular decompression for trigeminal neuralgia outcome.

Microvascular decompression for trigeminal neuralgia complications

Microvascular decompression for trigeminal neuralgia case series.


1)

Sivakanthan S, Van Gompel JJ, Alikhani P, van Loveren H, Chen R, Agazzi S. Surgical management of trigeminal neuralgia: use and cost-effectiveness from an analysis of the medicare claims database. Neurosurgery. 2014 Sep;75(3):220-6. doi: 10.1227/NEU.0000000000000430. PubMed PMID: 24871139.
2)

Pressman E, Jha RT, Zavadskiy G, Kumar JI, van Loveren H, van Gompel JJ, Agazzi S. Teflon™ or Ivalon®: a scoping review of implants used in microvascular decompression for trigeminal neuralgia. Neurosurg Rev. 2019 Nov 30. doi: 10.1007/s10143-019-01187-0. [Epub ahead of print] Review. PubMed PMID: 31786660.
3)

Yu F, Yin J. Young-onset trigeminal neuralgia: a clinical study and literature review. Acta Neurochir (Wien). 2021 Apr 17. doi: 10.1007/s00701-021-04848-6. Epub ahead of print. PMID: 33864143.
4)

Li Ching Ng A, Di Ieva A. How I do it: 3D exoscopic endoscope-assisted microvascular decompression. Acta Neurochir (Wien). 2019 May 29. doi: 10.1007/s00701-019-03954-w. [Epub ahead of print] PubMed PMID: 31144166.
5)

Peng WC, Guan F, Hu ZQ, Huang H, Dai B, Zhu GT, Mao BB, Xiao ZY, Zhang BL, Liang X. [Efficacy analysis of fully endoscopic microvascular decompression in primary trigeminal neuralgia via keyhole approach]. Zhonghua Yi Xue Za Zhi. 2021 Mar 30;101(12):856-860. Chinese. doi: 10.3760/cma.j.cn112137-20200630-02002. PMID: 33789367.
6)

Holste K, Chan AY, Rolston JD, Englot DJ. Pain Outcomes Following Microvascular Decompression for Drug-Resistant Trigeminal Neuralgia: A Systematic Review and Meta-Analysis. Neurosurgery. 2020 Feb 1;86(2):182-190. doi: 10.1093/neuros/nyz075. PubMed PMID: 30892607.
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