Medical treatment for tremors may include beta-blockers, primidone, dopaminergic, and anticholinergic drugs but it frequently leads to pharmacoresistance. Therefore, surgical treatment gained relevance as an alternative for those patients.We aim to evaluate radiosurgical thalamotomy as an effective and safe alternative to manage tremors. Pubmed (MEDLINE), Embase, Web of Science, and the Cochrane Library databases were systematically searched for potential articles that evaluated radiosurgical thalamotomy for the management of tremor. Our analysis included 12 studies with 545 patients, 226 of whom were female. Of these, 64.6% of patients were diagnosed with essential tremor (ET), 34.6% with Parkinson\'s disease (PD), and 0.8% with both ET and PD. The FTM-TRS global score (MD -5.46; 95% CI [-10.44]-[-0.47]; I2 = 52%) and the drawing (MD -1.40; 95% CI [-2.03]-[-0.76]; I2 = 93%), drinking (MD -1.60; 95% CI [-1.82]-[-1.37]; I2 = 40%), and writing (MD -1.51; 95% CI [-1.89]-[-1.13]; I2 = 89%) grades showed significantly lower mean differences, favoring radiosurgical thalamotomy. A pooled proportion of 12% presented with tremor unchanged, while 38% presented with total elimination of tremor. Adverse events included: major paresis, minor paresis, dysarthria, and numbness. Thus, radiosurgical thalamotomy is a safe alternative for tremors resistant to medication, particularly in high-risk patients for RF or DBS procedures. The recommended dose of 130 to 150 Gy is effective and well-tolerated. However, randomized controlled trials (RCTs) are needed to understand the unpredictability of tissue response to radiation.

UNASSIGNED: Essential tremor (ET) and Parkinson\'s Disease (PD) are debilitating neurodegenerative disorders characterized by tremor as a predominant symptom, significantly impacting patients\' quality of life. Magnetic Resonance-guided Focused Ultrasound (MRgFUS) Thalamotomy is an innovative therapeutic option for the treatment of unilateral medically refractory tremor with fewer adverse effects compared to traditional surgical interventions. A recent CE approval allows appropriate patients to have their second side treated.
UNASSIGNED: The objective of this systematic review was to analyze available current knowledge about the use of MRgFUS for the treatment of bilateral ET and PD related tremor, to identify the effectiveness and the risks associated with bilateral treatment.
UNASSIGNED: Eligible studies were identified by searching published studies in PubMed and Scopus databases from May 2014 to January 2024 and by identifying ongoing studies registered on the clinicaltrials.gov website. Data were summarized by considering the following information topics: the number of patients involved, the selected lesion target, the assessment tool used to evaluate clinical changes, the observed improvement, the reported side effects, and the time interval between the two treatments. The study was registered in PROSPERO (ID: CRD42024513178).
UNASSIGNED: Nine studies were eligible for this review, 7 for ET and 2 for PD. The involved population included a variable number of patients, ranging from 1 to 11 subjects for ET and from 10 to 15 subjects for PD. The main lesional targets were the ventral intermediate nucleus of the thalamus, the pallidothalamic tract and the cerebellothalamic tract bilaterally. All studies investigated the tremor relief through the Clinical Rating Scale for Tremor (CRST) in patients with ET, and through the Unified Parkinson\'s Disease Rating Scale (UPDRS) in patients with PD. A variable degree of improvement was observed, with all patients expressing overall satisfaction with the bilateral treatment. Adverse events were mild and transient, primarily involving gait disturbances, dysarthria, and ataxia. A standardized protocol for administering the two consecutive treatments was not identifiable; typically, the timing of the second treatment was delayed by at least 6 months.
UNASSIGNED: Available evidence supports the effectiveness and safety of staged bilateral MRgFUS treatments for ET and PD-related tremor.

Neuropathic pain (NP), resulting from damage to the somatosensory system, is characterized by either spontaneous or evoked pain. In the context of NP, wherein aberrant signaling pathways contribute to the perception of pain, the thalamus emerges as a key player. This structure is integral to the pain network that includes connections to the dorsal horn of the spinal cord, highlighting its role in the affective-motivational aspects of pain perception. Given its significant involvement, the thalamus is targeted in advanced treatments such as thalamotomy and deep brain stimulation (DBS) when traditional therapies fail, emphasizing the need to understand its function in NP to improve management strategies. This review aimed to provide an overview of the role of the thalamus in the transmission of nociceptive information in NP by discussing the existing evidence, including the effectiveness and safety of current techniques in the management and treatment of NP. This is an integrative review involving the qualitative analysis of scientific articles published in PubMed/MEDLINE, Embase, Scopus, and Web of Science. A total of 687 articles were identified, and after selection, 15 articles were included in this study. All studies reviewed demonstrated varying degrees of effectiveness of DBS and thalamotomy in alleviating painful symptoms, although the relief was often temporary. Many studies noted a reduction in pain perception at the conclusion of treatment compared to pre-treatment levels, with this decrease maintained throughout patient follow-ups. However, adverse events associated with these treatments were also reported. In conclusion, there are some benefits, albeit temporary, to using thalamotomy and DBS to alleviate the painful symptoms of NP. Both procedures are considered advanced forms of surgical intervention that aim to modulate pain pathways in the brain, providing significant relief for patients suffering from chronic pain resistant to conventional treatment. Despite limitations, these surgical interventions offer renewed hope for patients facing disabling chronic pain and can provide a significant improvement in quality of life.

BACKGROUND: Magnetic resonance guided focused ultrasound (MRgFUS) thalamotomy is an effective treatment for drug-resistant tremor. The most frequent side effects are ataxia, gait disturbance, paresthesias, dysgeusia, and hemiparesis. Here, we report the first case of thalamic hand dystonia rapidly occurring after MRgFUS thalamotomy of the ventral intermediate nucleus (V.im).
METHODS: MRgFUS thalamotomy was performed in a 60-year-old left-handed patient for his disabling medically refractory essential tremor. The intervention resulted in a marked reduction of his action tremor. However, the patient developed an unvoluntary abnormal posture in his left hand a few days after the procedure with difficulty holding a cigarette between his fingers. Brain MRI revealed the expected MRgFUS lesion within the right V.im as well as an extension of the lesion anteriorly to the V.im in the ventro-oralis nucleus. Tractography showed that the lesion disrupted the dentato-rubro-thalamic tract as expected with a lesion suppressing tremor. However, the lesion also was interrupted fibers connecting to the superior frontal and pre-central cortices (primary motor cortex, premotor cortex, and supplementary area). We hypothesized that the interventional MRgFUS thalamotomy was slightly off target, which induced a dysfunction within the cortico-striato-thalamo-cortical network and the cerebello-thalamo-cortical pathway reaching a sufficient threshold of basal ganglia/cerebellum circuitry interference to induce dystonia.
CONCLUSIONS: This rare side effect emphasizes the risk of imbalance within the dystonia network (i.e., basal ganglia-cerebello-thalamo-cortical circuit) secondary to V.im thalamotomy.

BACKGROUND: Essential tremor is a neurological condition associated with movement disorder with more prevalence among adult group of population. The burden of essential tremor is peaking globally but with the advancement in the area of functional neurosurgery such as stereotactic thalamotomy, the quality of life of such patients can be improved drastically.
METHODS: This systemic review was conducted in accordance to the guidance of preferred Reporting items for Systematic Review and Meta-Analysis(PRISMA). Databases of \"PubMed\", \"Embase\", \"Web of Science\", \"Cinhal Plus\", and \"Scopus\" from inception till 2023 was undertaken. A combination of keywords, Medical Subject Headings (MeSH), and search terms such as Search strategy for PubMed search was as follows: \"stereotactic thalamotomy\" AND \"essential tremor\".
RESULTS: This systematic review analyzed 9 studies with a total of 274 patients of essential tremor patients. Unilateral thalamotomy was carried out among 268 patients and bilateral thalamotomy in rest of the patients. Vim and Vom nucleus were the site of thalamotmy with ventral intermedius nucleus being the major one. Ten different types of clinical tremor rating scales were used to assess pre operative and post operative improvement in the tremor scales of the individual patients. Dysarthria and limb weakness was noted post operative complication in majority of the cases.
CONCLUSIONS: Our study revealed that stereotactic thalamotomy provided good functional outcome in patients of essential tremor who underwent unilateral thalamotomy compared to bilateral thalamotomy. The positive outcome outweighs the complications in such functional surgery.

OBJECTIVE: Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is an emerging technique for the treatment of severe, medication-refractory tremor syndromes. We here report motor and non-motor outcomes 6 and 12 months after unilateral MRgFUS thalamotomy in tremor-dominant Parkinson\'s disease (tdPD).
METHODS: 25 patients with tdPD underwent neuropsychological evaluation including standardized questionnaires of disability, quality of life (QoL), mood, anxiety, apathy, sleep disturbances, and cognition at baseline, 6 and 12 months after MRgFUS. Motor outcome was evaluated using the Clinical Rating Scale for Tremor (CRST) and Movement Disorder Society-Unified Parkinson\'s Disease Rating Scale (MDS-UPDRS). In addition, side effects and QoL of family caregivers were assessed.
RESULTS: 12 months after MRgFUS significant improvements were evident in the tremor subscores. Patients with concomitant rest and postural tremor showed better tremor outcomes compared to patients with predominant rest tremor. There were no differences in the non-motor assessments. No cognitive decline was observed. Side effects were mostly transient (54%) and classified as mild (62%). No changes in the caregivers\' QoL could be observed.
CONCLUSIONS: We found no changes in mood, anxiety, apathy, sleep, cognition or persistent worsening of gait disturbances after unilateral MRgFUS thalamotomy in tdPD. Concomitant postural tremors responded better to treatment than predominant rest tremors.

UNASSIGNED: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy of the ventralis intermediate (Vim) nucleus is an \"incisionless\" treatment for medically refractory essential tremor (ET). We present data on 49 consecutive cases of MRgFUS Vim thalamotomy followed-up for 3 years and review the literature on studies with longer follow-up data.
UNASSIGNED: A retrospective chart review of patients who underwent MRgFUS thalamotomy (January 2018-December 2020) at our institution was performed. Clinical Rating Scale for Tremor (CRST) and Quality of Life in Essential Tremor (QUEST) scores were obtained pre-operatively and at each follow-up with an assessment of side effects. Patients had post-operative magnetic resonance imaging within 24 h and at 1 month to figure out lesion location, size, and extent. The results of studies with follow-up ≥3 years were summarized through a literature review.
UNASSIGNED: The CRST total (baseline: 58.6 ± 17.1, 3-year: 40.8 ± 18.0) and subscale scores (A + B, baseline: 23.5 ± 6.3, 3-year: 12.8 ± 7.9; C, baseline: 12.7 ± 4.3, 3-year: 5.8 ± 3.9) and the QUEST score (baseline: 38.0 ± 14.8, 3-year: 18.7 ± 13.3) showed significant improvement that was stable during the 3-year follow-up. Three patients reported tremor recurrence and two were satisfactorily retreated. Side effects were reported by 44% of patients (severe: 4%, mild and transient: 40%). The improvement in tremor and quality of life in our cohort was consistent with the literature.
UNASSIGNED: We confirmed the effectiveness and safety of MRgFUS Vim thalamotomy in medically refractory ET up to 3 years.

UNASSIGNED: Essential tremor (ET) is the most frequent movement disorder, affecting up to 5% of adults > 65 years old. In 30-50% of cases, optimal medical management provides insufficient tremor relief and surgical options are considered. Thalamotomy is a time-honored intervention, which can be performed using radiofrequency (RF), stereotactic radiosurgery (SRS), or magnetic resonance-guided focused ultrasounds (MRgFUS). While the latter has received considerable attention in the last decade, SRS has consistently been demonstrated as an effective and well-tolerated option.
UNASSIGNED: This review discusses the evidence on SRS thalamotomy for ET. Modern workflows and emerging techniques are detailed. Current outcomes are analyzed, with a specific focus on tremor reduction, complications and radiological evolution of the lesions. Challenges for the field are highlighted.
UNASSIGNED: SRS thalamotomy improves tremor in > 80% patients. The efficacy appears comparable to other modalities, including DBS, RF and MRgFUS. Side effects result mostly from idiosyncratic hyper-responses to radiation, which occur in up to 10% of treatments, are usually self-resolving, and are symptomatic in < 4% of patients. Future research should focus on accumulating more data on bilateral treatments, collecting long-term outcomes, refining targeting, and improving lesion consistency.

UNASSIGNED: Skull density ratio (SDR) is the ratio between the mean Hounsfield units of marrow and cortical bone, impacting energy transmission through the skull. Low SDR has been used as an exclusion criterion in major trials of magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for medication-refractory essential tremor (ET). However, some studies have suggested that patients with low SDR can safely undergo MRgFUS with favorable outcomes. In this case-matched study, we aim to compare the characteristics, sonication parameters, lesion sizes, and clinical outcomes of patients with low SDR vs. patients with high SDR who underwent unilateral MRgFUS thalamotomy for medication-refractory ET.
UNASSIGNED: Between March 2016 and April 2023, all patients (n = 270) who underwent unilateral MRgFUS thalamotomy for medication-refractory ET at a single institution were classified as low SDR (<0.40) and high SDR (≥0.40). All clinical and radiological data was prospectively collected and retrospectively analyzed using non-case-matched and 1:1 case-matched methodology.
UNASSIGNED: Thirty-one patients had low SDR, and 239 patients had high SDR. Fifty-six patients (28 in each cohort) were included in 1:1 case-matched analysis. There were no significant differences in baseline characteristics between the two groups in both non-case-matched and 1:1 case-matched analyses. In both analyses, compared to patients with high SDR, patients with low SDR required a significantly higher maximum sonication power, energy, and duration, and reached a lower maximum temperature with smaller lesion volumes. In the non-case-matched and case-matched analyses, low SDR patients did not have significantly less tremor control at any postoperative timepoints. However, there was a higher chance of procedure failure in the low SDR group with three patients not obtaining an appropriately sized lesion. In both analyses, imbalance was observed more often in high SDR patients on postoperative day 1 and month 3.
UNASSIGNED: ET patients with SDR <0.40 can be safely and effectively treated with MRgFUS, though there may be higher rates of treatment failure and intraoperative discomfort.

OBJECTIVE: To determine the best predictor of lesion volume induced by magnetic resonance (MR)-guided focused ultrasound (MRgFUS) thalamotomy in patients with tremor-dominant symptoms in Parkinson\'s disease (PD) and essential tremor (ET) patients.
METHODS: Thirty-six neurological patients with medication-refractory tremor (n°19 PD; n°17 ET) were treated using a commercial MRgFUS brain system (Exablate Neuro 4000, Insightec) integrated with a 1.5 T MRI unit (Sigma HDxt; GE Medical System). Linear regression analysis was used to determine how the demographic, clinical, radiological (Fazekas scale), volumetric (total GM/WM/CSF volume, cortical thickness), and MRgFUS-related parameters [Skull Density Ratio (SDR), n° of transducer elements, n° of sonications, skull area, maximal energy delivered (watt), maximal power delivered (joule), maximal sonication time delivered, maximal mean temperature reached (T°C_max), accumulated thermal dose (ATD)] impact on ventral intermediate (VIM)-thalamotomy-related 3D volumetric lesions of necrosis and edema.
RESULTS: The VIM thalamotomy was clinically efficacious in improving the tremor symptoms of all the patients as measured at 1 week after treatment. Multiple regression analysis revealed that T°C_max and n° of transducer elements were the best predictors of the necrosis and edema volumes. Moreover, total WM volume also predicted the size of necrosis.
CONCLUSIONS: Our study provides new insights into the clinical MRgFUS procedures that can be used to forecast brain lesion size and improve treatment outcomes.