Unilateral Stereotactic Radiofrequency Lesioning as a Surgical Treatment Option for Meige Syndrome.

Background Meige syndrome is a segmental dystonia affecting the head and neck, with bilateral blepharospasm as the primary symptom. First-line treatment typically involves Botox injections. For cases resistant to this treatment, bilateral deep brain stimulation of the globus pallidus internus (GPi) is considered. This study explores the efficacy of unilateral radiofrequency (RF) lesioning as an alternative surgical treatment for Meige syndrome. Methods We investigated six cases of medically refractory Meige syndrome treated with unilateral RF lesioning between October 2022 and August 2023. The procedures utilized the Leksell Stereotactic System (Elekta, Stockholm, Sweden) and the StealthStation S8 system (Medtronic, Dublin, Ireland). Target coordinates were initially set at 8-9 mm lateral and 1-2 mm inferior to the mid-commissure point (MCP) for the pallidothalamic tract (PTT), and 20 mm lateral, 2 mm anterior, and 3.0-4.5 mm inferior to the MCP for GPi, with fine adjustments based on MRI findings. Results The mean age of patients was 53. 3 ±16.5 years. Five patients underwent PTT RF lesioning, while one received GPi RF lesioning (pallidotomy). No surgical complications were reported. The Burke-Fahn-Marsden Dystonia Rating Scale scores were 32.9 ± 19.4 preoperatively and 17.7 ± 13.9 three months postoperatively, reflecting an average improvement of 42.7%. The Jankovic Rating Scale scores were 7.17 ± 0.76 preoperatively, 2.33 ± 2.34 the day after surgery (average improvement of 67%), and 3.50 ± 1.64 three months postoperatively (average improvement of 51%). Bilateral facial symptoms improved in four patients (67%). Conclusion Unilateral RF lesioning for Meige syndrome demonstrated the potential to improve bilateral symptoms and may be considered a viable treatment option for patients with refractory cases.

Long-term follow-up of task-specific tremor after thalamotomy: a retrospective observational study.

OBJECTIVE: This study aimed to report the long-term results of thalamotomy in 23 patients with task-specific tremor. METHODS: Data of 23 patients with task-specific tremor who underwent ventralis intermedius nucleus and posterior part of ventro-oral nucleus thalamotomy at the Tokyo Women's Medical University Hospital between 2010 and 2022 were retrospectively analyzed. To evaluate neurological conditions, the severity of task-specific tremor was divided into 0 (no tremor), 1 (slightly tremulous), 2 (moderately tremulous), 3 (accomplishing tasks with great difficulty), and 4 (unable to complete tasks). We also used the subscores "handwriting" (0-4) and "spiral drawing" (0-4) of the Clinical Rating Scales for Tremor. Evaluation scales were presented as medians and interquartile ranges. RESULTS: The severities of task-specific tremor were 3.0 (3.0-4.0) preoperatively and 0.0 (0.0-0.0, p < 0.0001) at the last available evaluation. The writing and spiral drawing of the Clinical Rating Scales for Tremor significantly improved from 3.0 (3.0-4.0) and 3.0 (2.0-3.0) preoperatively, respectively, to 0.0 (0.0-0.0, p < 0.0001) and 0.0 (0.0-0.0, p < 0.0001) at the last available evaluation, respectively. The mean clinical follow-up period was 62.7 ± 26.0 months. Seven (30.4%) patients had focal hand dystonia, which newly developed on the ipsilateral side of the tremor at 2-45 months after the surgery. No serious complications were observed. INTERPRETATION: Thalamotomy significantly improves task-specific tremor with high long-term efficacy, and long-term follow-up is important because focal hand dystonia can develop postoperatively.

A novel high-precision fiber tractography for nuclear localization in transcranial magnetic resonance-guided focused ultrasound surgery: a pilot study.

OBJECTIVE: In transcranial MR-guided focused ultrasound (TcMRgFUS), fiber tractography using diffusion tensor imaging (DTI) has been proposed as a direct method to identify the ventral intermediate nucleus (Vim), the ventral caudal nucleus (Vc), and the pyramidal tract (PT). However, the limitations of the DTI algorithm affect the accuracy of visualizing anatomical structures due to its low-quality fiber tractography, whereas the application of the generalized q-sampling imaging (GQI) algorithm enables the visualization of high-quality fiber tracts, offering detailed insights into the spatial distribution of motor cortex fibers. This retrospective study aimed to investigate the usefulness of high-precision fiber tractography using the GQI algorithm as a planning image in TcMRgFUS to achieve favorable clinical outcomes. METHODS: This study included 20 patients who underwent TcMRgFUS. The Clinical Rating Scale for Tremor (CRST) scores and MR images were evaluated pretreatment and at 24 hours and 3-6 months after treatment. Cases were classified based on the presence and adversity of adverse events (AEs): no AEs, mild AEs without additional treatment, and severe AEs requiring prolonged hospitalization. Fiber tractography of the Vim, Vc, and PT was visualized using the DTI and GQI algorithm. The overlapping volume between Vim fibers and the lesion was measured, and correlation analysis was performed. The relationship between AEs and the overlapping volume of the Vc and PT fibers within the lesions was examined. The cutoff value to achieve a favorable clinical outcome and avoid AEs was determined using receiver operating characteristic curve analysis. RESULTS: All patients showed improvement in tremors 24 hours after treatment, with 3 patients experiencing mild AEs and 1 patient experiencing severe AEs. At the 3- to 6-month follow-up, 5 patients experienced recurrence, and 2 patients had persistent mild AEs. Although fiber visualization in the motor cortex using the DTI algorithm was insufficient, the GQI algorithm enabled the visualization of significantly higher-quality fibers. A strong correlation was observed between the overlapping volume that intersects the lesion and Vim fibers and the degree of tremor improvement (r = 0.72). Higher overlapping volumes of Vc and PT within the lesion were associated with an increased likelihood of AEs (p < 0.05); the cutoff volume of Vim fibers within the lesion for a favorable clinical outcome was 401 mm3, while the volume of Vc and PT within the lesion to avoid AEs was 99 mm3. CONCLUSIONS: This pilot study suggests that incorporating the high-precision GQI algorithm for fiber tractography as a planning imaging technique for TcMRgFUS has the potential to enhance targeting precision and achieve favorable clinical outcomes.

Abolition of seizures following Forel-H-tomy for drug-resistant epilepsy: A case report.

A 62-year-old female experienced an extensive cerebral contusion in the left frontotemporal lobe due to an acute subdural hematoma at the age of 44 years. Six months after the injury, the patient developed epileptic seizures. The seizures were generalized with right cervical rotation and fencing posture. Despite prescriptions for four antiepileptic drugs, partial seizures occurred several times a month and focal to bilateral tonic-clonic seizures once every 2 months. Video-electroencephalography showed epileptic discharges in the left frontal lobe. The patient was subsequently referred to our department for palliative surgery. The patient underwent a left Forel-H-tomy. The prescription of antiepileptic drugs was not changed, and the patient was seizure free for 1 year. Forel-H-tomy, a surgical procedure for intractable epilepsy, was pioneered by Dennosuke Jinnai. Despite its previously reported remarkable efficacy, Forel-H-tomy has not been performed for several decades. Nevertheless, it remains a potential alternative treatment option for drug-resistant epilepsy.

Improvement in Intraoperative Image Quality in Transcranial Magnetic Resonance-Guided Focused Ultrasound Surgery Using Transmitter Gain Adjustment.

INTRODUCTION: Transcranial magnetic resonance-guided focused ultrasound surgery (TcMRgFUS) has the advantage of allowing immediate evaluation of therapeutic effects after each sonication and intraoperative magnetic resonance imaging (MRI) to visualize the lesion. When the image shows that the lesion has missed the planned target and the therapeutic effects are insufficient, the target of the subsequent ablation can be finely adjusted based on the image. The precision of this adjustment is determined by the image quality. However, the current intraoperative image quality with a 3.0T MRI system is insufficient for precisely detecting the lesion. Thus, we developed and validated a method for improving intraoperative image quality. METHODS: Because intraoperative image quality is affected by transmitter gain (TG), we acquired T2-weighted images (T2WIs) with two types of TG: the automatically adjusted TG (auto TG) and the manually adjusted TG (manual TG). To evaluate the character of images with 2 TGs, the actual flip angle (FA), the image uniformity, and the signal-to-noise ratio (SNR) were measured using a phantom. Then, to assess the quality of intraoperative images, T2WIs with both TGs were acquired during TcMRgFUS for 5 patients. The contrast-to-noise ratio (CNR) of the lesion was retrospectively estimated. RESULTS: The images of the phantom with the auto TG showed substantial variations between the preset and actual FAs (p < 0.01), whereas on the images with the manual TG, there were no variations between the two FAs (p > 0.05). The total image uniformity was considerably lower with the manual TG than with the auto TG (p < 0.01), indicating that the image's signal values with the manual TG were more uniform. The manual TG produced significantly higher SNRs than the auto TG (p < 0.01). In the clinical study, the lesions were clearly detected in intraoperative images with the manual TG, but they were difficult to identify in images with the auto TG. The CNR of lesions in images with manual TG was considerably higher than in images with auto TG (p < 0.01). CONCLUSION: Regarding intraoperative T2WIs using a 3.0T MRI system during TcMRgFUS, the manual TG method improved image quality and delineated the ablative lesion more clearly than the current method with auto TG.

Gamma Knife Thalamotomy for Essential Tremor: A Retrospective Analysis.

BACKGROUND: Gamma knife (GK) thalamotomy has been used as a treatment option for essential tremor (ET). Numerous studies on GK use in ET treatment have reported more varied responses and complication rates. METHODS: Data from 27 patients with ET who underwent GK thalamotomy were retrospectively analyzed. The Fahn-Tolosa-Marin Clinical Rating Scale for Tremor, handwriting, and spiral drawing were evaluated. Postoperative adverse events and magnetic resonance imaging findings were also evaluated. RESULTS: The mean age at GK thalamotomy was 78.1 ± 4.2 years. The mean follow-up period was 32.5 ± 19.4 months. The preoperative postural tremor, handwriting, and spiral drawing scores were 3.4 ± 0.6, 3.3 ± 1.0, and 3.2 ± 0.8, respectively, all of which showed significant improvements to 1.5 ± 1.2 (55.9% improvement, P < 0.001), 1.4 ± 1.1 (57.6% improvement, P < 0.001), and 1.6 ± 1.3 (50% improvement, P < 0.001), respectively, at the available final follow-up evaluations. Three patients presented with no improvement in tremor. Six patients presented with adverse effects, including complete hemiparesis, foot weakness, dysarthria, dysphagia, lip numbness, and finger numbness, at the final follow-up period. Two patients presented with serious complications, including complete hemiparesis due to massive widespread edema and chronic encapsulated expanding hematoma. One patient died of aspiration pneumonia following severe dysphagia secondary to chronic encapsulated expanding hematoma. CONCLUSIONS: GK thalamotomy is an efficient procedure for treating ET. Careful treatment planning is necessary to reduce complication rates. The prediction of radiation complications will increase the safety and effectiveness of GK treatment.

Successful treatment of focal hand dystonia after cervical whiplash injury by thalamotomy.

Background: Posttraumatic focal hand dystonia after cervical whiplash injury is rare. Moreover, the treatment of peripheral posttraumatic dystonia is usually ineffective. Herein, we report a case of successful thalamotomy for a patient with focal hand dystonia after cervical whiplash injury. Case Description: A 39-year-old woman was hit from behind by a car; subsequently, she felt strange in the right hand and was diagnosed with whiplash injury. A month later, she developed a persistent abnormal posture of the right hand. Brain imaging showed no lesions, and cervical magnetic resonance imaging showed stenosis but no spinal cord signal changes. Posttraumatic dystonia was diagnosed, for which the patient underwent left ventro-oral (Vo) thalamotomy. One year after the first surgery, the patient underwent left Vo and ventral intermediate nucleus (Vim) thalamotomy due to recurrence of dystonia. Nine years after the second surgery, the patient continues to be able to maintain her normal physical routine. Conclusion: Vo-Vim thalamotomy may be a feasible and effective treatment for focal hand dystonia after cervical whiplash injury.

Case report on ear numbness following deep brain stimulation implantation.

INTRODUCTION AND IMPORTANCE: Deep brain stimulation (DBS) implantation is a neurosurgical procedure in which electrodes are implanted in the brain. Complications that may occur include wound infection, issues with the DBS hardware, and others. This case report presents a patient who suffered ear numbness following DBS implantation. CASE PRESENTATION: A 50-year-old man presented with resting tremors in both hands. He reported that his handwriting had worsened and his movements had slowed. Physical examination revealed rigidity and postural instability. The patient was diagnosed with Parkinson's disease and a bilateral subthalamic nucleus DBS implantation was scheduled combined with the patient's medication all this time. Patient's symptoms showed improvement after the procedure. However, the patient complained of ear numbness and occasional pain in the area around his ear. We observed the patient over the next 3 months and the symptoms eventually resolved without any medication and intervention. CLINICAL DISCUSSION: Ear numbness is a rare complication that occasionally occurs after DBS implantation. This complication occurs because the tunneling track's proximity to the great auricular nerve and the lesser occipital nerve can result in accidental damage to either one or both of these nerves during subcutaneous tunneling. CONCLUSION: We suggest a simple procedure to avoid neural injury while maintaining the course of the tunneling in which the tunnel is created below the periosteum rather than at the subcutaneous level.

Chronic Encapsulated Expanding Hematoma After Gamma Knife Thalamotomy for Essential Tremor.

There have been no previous reports of chronic encapsulated expanding hematoma after Gamma Knife thalamotomy. The present case underwent Gamma Knife thalamotomy for essential tremor at the age of 78 years. Three- and 12-month posttreatment magnetic resonance imaging (MRI) showed small T2 high-intensity lesions on the target and along with the internal capsule. Hemiparesis developed 17 months after the treatment. Twenty months post treatment, T2-MRI showed a hypointense mass across the target and internal capsule. Gradual expansion of the mass was confirmed on MRI at 26-38 months. A 54-month posttreatment MRI showed marked expansion of the mass with multiple cysts surrounded by a T2-hypointense rim. Gadolinium-enhanced T1-MRI showed partial enhancement of the mass. MRI findings suggested a radiation-induced cavernoma. Hemiparesis, dysesthesia, and pain on the right side of the body persisted even after steroid therapy for several months. Long-term careful observation is necessary after Gamma Knife thalamotomy.

Intraparenchymal Symptomatic Cyst Formation Around the Deep Cerebellar Stimulation Electrode.

Intraparenchymal cyst formation around a deep brain stimulation electrode is a rare complication. This is the first report of intraparenchymal cyst formation along a deep cerebellar stimulation electrode in the posterior cranial fossa. The patient was a 27-year-old man with DYT-1 early-onset isolated dystonia who received bilateral deep cerebellar stimulation. He developed dizziness, nausea, and dysarthria 1 month following the deep cerebellar stimulation surgery. Head computed tomography revealed multiple cysts along the left electrode. The contrast medium of computed tomography did not enhance the appearance of the cystic lesions. We confirmed the absence of fever and sterile cerebrospinal fluid. Steroid therapy for 3 weeks was not radiologically and symptomatically useful. He underwent aspiration surgery. The cyst fluid was light yellow, sterile, and rich in protein. Despite substantial improvement in nausea and dysarthria within 1 week postoperatively, dizziness required 1 month to recover. Cystic formations gradually decreased with time.

Seven-year resolution of cervical dystonia after unilateral pallidotomy: A case report.

Background: Reports on the long-term effects of pallidotomy for cervical dystonia remain scarce. Case Description: We report a case of cervical dystonia successfully treated by unilateral pallidotomy. The patient was a 29-year-old man without past medical and family history of cervical dystonia. At the age of 28 years, neck rotation to the right with right shoulder elevation developed and gradually became worse. After symptoms failed to respond to repetitive botulinum toxin injections and oral medications, he underwent left pallidotomy, which resulted in significant improvement of cervical dystonia and shoulder elevation without surgical complications. At the 3-month evaluation, the symptoms completely improved. The Toronto Western Spasmodic Torticollis Rating Scale score dramatically improved from 39 points before surgery to 0 points at 7-year postoperative evaluation. Conclusion: This case suggests that unilateral pallidotomy can be an alternative treatment option for cervical dystonia.

Case Report: Long-Term Suppression of Paroxysmal Kinesigenic Dyskinesia After Bilateral Thalamotomy.

Background: Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by transient dyskinetic movements, including dystonia, chorea, or both, triggered by sudden voluntary movements. Carbamazepine and other antiepileptic drugs (AEDs) are widely used in the treatment of PKD, and they provide complete remission in 80-90% of medically treated patients. However, the adverse effects of AEDs include drowsiness and dizziness, which interfere with patients' daily lives. For those with poor compatibility with AEDs, other treatment approaches are warranted. Case Report: A 19-year-old man presented to our institute with right hand and foot dyskinesia. He had a significant family history of PKD; his uncle, grandfather, and grandfather's brother had PKD. The patient first experienced paroxysmal involuntary left hand and toe flexion with left forearm pronation triggered by sudden voluntary movements at the age of 14. Carbamazepine (100 mg/day) was prescribed, which led to a significant reduction in the frequency of attacks. However, carbamazepine induced drowsiness, which significantly interfered with his daily life, especially school life. He underwent right-sided ventro-oral (Vo) thalamotomy at the age of 15, which resulted in complete resolution of PKD attacks immediately after the surgery. Four months after the thalamotomy, he developed right elbow, hand, and toe flexion. He underwent left-sided Vo thalamotomy at the age of 19. Immediately after the surgery, the PKD attacks resolved completely. However, mild dysarthria developed, which spontaneously resolved within three months. Left-sided PKD attacks never developed six years after the right Vo thalamotomy, and right-sided PKD attacks never developed two years after the left Vo thalamotomy without medication. Conclusion: The present case showed long-term suppression of bilateral PKDs after bilateral thalamotomy, which led to drug-free conditions.

Deep Brain Stimulation of the Forel's Field for Dystonia: Preliminary Results.

The field of Forel (FF) is a subthalamic area through which the pallidothalamic tracts originating from the globus pallidus internus (GPi) traverse. The FF was used as a stereotactic surgical target (ablation and stimulation) to treat cervical dystonia in the 1960s and 1970s. Although recent studies have reappraised the ablation and stimulation of the pallidothalamic tract at FF for Parkinson's disease, the efficacy of deep brain stimulation of FF (FF-DBS) for dystonia has not been well investigated. To confirm the efficacy and stimulation-induced adverse effects of FF-DBS, three consecutive patients with medically refractory dystonia who underwent FF-DBS were analyzed (tongue protrusion dystonia, cranio-cervico-axial dystonia, and hemidystonia). Compared to the Burke-Fahn-Marsden Dystonia Rating Scale-Movement Scale scores before surgery (23.3 ± 12.7), improvements were observed at 1 week (8.3 ± 5.9), 3 months (5.3 ± 5.9), and 6 months (4.7 ± 4.7, p = 0.0282) after surgery. Two patients had stimulation-induced complications, including bradykinesia and postural instability, all well controlled by stimulation adjustments.

[History and Present of Stereotactic and Functional Neurosurgery].

Stereotactic and functional neurosurgery(SFN)is one of the oldest subspecialties of neurosurgery. In Japan, functional epilepsy surgery was performed in the Meiji era, even before World War II, when general surgeons used to operate on patients with intractable cancer pain through open myelotomy or cordotomy. Knowledge gathered from such age-old procedures provided the basic understanding of neurophysiology and hence, functional neurosurgery used to be termed as "applied neurophysiology". Human stereotactic surgery was introduced in 1947 and many Japanese neurosurgeons, particularly Hirotaro Narabayashi, Keiji Sano and Chihiro Ohye, contributed to the development of this field. Additionally, we should remember that common procedures of neurosurgery practiced today such as neuroendoscopy, navigation surgery, intraoperative monitoring, and the concept of exo-scope, which are less invasive and involves high accuracy, emerged from the field of SFN. Young doctors should learn from history and understand where we started from, where we at present, and where we are heading in the future.

[Radiofrequency Lesioning Surgery for Movement Disorders].

Radiofrequency lesioning surgery is primarily performed to treat Parkinson's disease, dystonia, and tremor. Its effects are similar to those of deep brain stimulation (DBS). However, Radiofrequency lesioning surgery has not been popularized, possibly due to the over-evaluation of its risks. The current most available targets for the treatment of movement disorders include ventral intermediate (Vim) nucleus, ventral oral (Vo) nucleus, and globus pallidus internus (GPi). Vim thalamotomy is available for Parkinsonian tremor, essential tremor, dystonic tremor, and other various kinds of tremor, and it is highly effective. Bilateral vim thalamotomy is feasible when properly performed on tiny lesions on the bilateral vim nucleus. Vo thalamotomy is mainly available for focal hand dystonia. The safety profile of bilateral Vo thalamotomy has not yet been established, but it is thought that it may lead to irreversible hypophonia and dysarthria. Pallidotomy is selected for treatment of dystonia and Parkinson's disease. Although unilateral pallidotomy is a safe procedure, it can cause medically refractory parkinsonism including postural reflex disturbance and gait disorder. Delayed infarction on the posterior limb of internal capsule is another major concern associated with pallidotomy and can lead to hemiparesis. Correct understanding is absolutely essential to ensure the safety of radiofrequency lesioning surgery.

Radiofrequency Ablation for Movement Disorders: Risk Factors for Intracerebral Hemorrhage, a Retrospective Analysis.

BACKGROUND: One of the greatest concerns associated with radiofrequency ablation is intracerebral hemorrhage (ICH). However, the majority of previous studies have mainly evaluated Parkinson disease patients with ablation of the globus pallidus internus (GPi). OBJECTIVE: To investigate the hemorrhagic risk associated with radiofrequency ablation using ventro-oral (Vo) nucleus, ventral intermediate (Vim) nucleus, GPi, and pallidothalamic tract. METHODS: Radiofrequency ablations for movement disorders from 2012 to 2019 at our institution were retrospectively analyzed. Multivariate analyses were performed to evaluate associations between potential risk factors and ICH. RESULTS: A total of 558 patients underwent 721 stereotactic radiofrequency ablations for movement disorders. Among 558 patients, 356 had dystonia, 111 had essential tremor, and 51 had Parkinson disease. Among 721 procedures, the stereotactic targets used in this study were as follows: Vo: 230; Vim: 199; GPi: 172; pallidothalamic tract: 102; Vim/Vo: 18. ICH occurred in 37 patients (5.1%, 33 with dystonia and 4 with essential tremor). Symptomatic ICH developed in 3 Vo nuclei (1.3%), 3 Vim nuclei (1.5%), and 2 GPi (1.2%). Hypertension (odds ratio = 2.69, P = .0013), higher number of lesions (odds ratio = 1.23, P = .0221), and younger age (odds ratio = 1.04, P = .0055) were significant risk factors for ICH associated with radiofrequency ablation. CONCLUSION: The present study revealed that younger age, higher number of lesions, and history of hypertension were independent risk factors for ICH associated with stereotactic radiofrequency ablation.

Case Report: Deep Cerebellar Stimulation for Tremor and Dystonia.

Background: The cerebellum plays an important role in the pathogenesis and pathophysiology of movement disorders, including tremor and dystonia. To date, there have been few reports on deep cerebellar stimulation. Case Report: The patient was a 35-year-old previously healthy man with no history of movement disorders. He developed a tremor and stiffness in his left hand at the age of 27 years, which was diagnosed as a dystonic tremor. We performed right thalamotomy, which resulted in a complete resolution of the tremor; however, the dystonia persisted. Subsequently, the patient developed left foot dystonia with inversion and a newly developed tremor in the right hand and foot. The patient underwent left ventralis intermedius (VIM) deep brain stimulation (VIM-DBS) and left pallidothalamic tract DBS (PTT-DBS). Left VIM-DBS completely resolved the right hand and foot tremor, and PTT-DBS significantly improved the left hand and foot dystonia. Three months postoperatively, the patient developed an infection and wound disruption at the surgical site. We performed palliative surgery for deep cerebellar stimulation via the posterior cranial region, which was not infected. The surgery was performed under general anesthesia with the patient lying in the prone position. Eight contact DBS electrodes were used. The placement of electrodes extended from the superior cerebellar peduncle to the dentate nucleus. Both the right hand and foot tremor improved with right cerebellar stimulation. Further, both the left hand and foot dystonia improved with left cerebellar stimulation. Right and left cerebellar stimulation led to no improvement in the left hand and foot dystonia and right hand and foot tremor, respectively. Stimulation-induced complications observed in the patient included dizziness, dysphagia, and dysarthria. After the surgery, the patient developed hypersalivation and hyperhidrosis in the left side of the body, both of which did not improve with adjustments of stimulation parameters. At the 6-month follow-up, the tremor and dystonia had almost completely resolved. Conclusion: Deep cerebellar stimulation deserves consideration as a potential treatment for tremor and dystonia.

Safety and efficacy of unilateral and bilateral pallidotomy for primary dystonia.

OBJECTIVE: Ablation of the globus pallidus internus (pallidotomy) is an effective surgical intervention for dystonia. However, the current literature on the efficacy and safety of pallidotomy for dystonia is derived only from single-case reports and small cohort studies. METHODS: We retrospectively analyzed patients with primary dystonia who underwent pallidotomy at our institution between 2014 and 2019. Neurological conditions were evaluated using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS, range: 0-120). We evaluated the total BFMDRS score and each subitem score (nine body regions) in the patients who underwent unilateral and bilateral pallidotomy before surgery and at last available follow-up. Moreover, postoperative complications were analyzed. RESULTS: We found that 69 and 20 patients underwent unilateral and bilateral pallidotomy respectively. The mean age at dystonia onset was 40.4 ± 15.2 years. The mean clinical follow-up period was 17.2 ± 11.6 months. Unilateral pallidotomy significantly improved the total BFMDRS score from 11.2 ± 14.7 preoperatively to 5.4 ± 7.6 at last available follow-up (51.8% improvement, p < 0.001). Furthermore, there was a significant and independent improvement in all midline BFMDRS subitems, including eyes, mouth, speech/swallow, and neck, after unilateral pallidotomy. Bilateral pallidotomy significantly improved the total BFMDRS score from 14.6 ± 10.2 preoperatively to 3.8 ± 8.2 at last available follow-up (74.0% improvement, p < 0.001). However, bilateral pallidotomy induced medically refractory parkinsonism (postural instability and gait disturbance) in five patients, dysarthria in three patients, and dysphagia in one patient. INTERPRETATION: Unilateral radiofrequency pallidotomy remains a viable treatment option for patients with some forms of dystonia. Bilateral pallidotomy cannot be recommended due to unacceptably high complication rates.

Comorbid seizure reduction after pallidothalamic tractotomy for movement disorders: Revival of Jinnai's Forel-H-tomy.

Forel-H-tomy for intractable epilepsy was introduced by Dennosuke Jinnai in the 1960s. Recently, Forel-H-tomy was renamed to "pallidothalamic tractotomy" and revived for the treatment of Parkinson's disease and dystonia. Two of our patients with movement disorders and comorbid epilepsy experienced significant seizure reduction after pallidothalamic tractotomy, demonstrating the efficacy of this method. The first was a 29-year-old woman who had temporal lobe epilepsy with focal impaired awareness seizure once every three months and an aura 10-20 times daily, even with four antiseizure medicines. For the treatment of hand dyskinesia, she underwent left pallidothalamic tractotomy and her right-hand dyskinesia significantly improved. Fourteen months later, she had experienced no focal impaired awareness seizure and the aura decreased to one to three times per month. The second case was that of a 15-year-old boy diagnosed with progressive myoclonic epilepsy, who developed generalized tonic-clonic seizure, which manifested once every month, despite treatment with five antiseizure medicines. After surgery, myoclonic movements in his right hand slightly improved. A one-year follow-up revealed that he had not experienced a generalized tonic-clonic seizure. The lesion locations in the two cases were close to the vicinity of Jinnai's Forel-H-tomy. Forel's field H deserves reconsideration as a treatment target for intractable epilepsy.

Long-Term Successful Outcome of Dystonic Head Tremor after Bilateral Deep Brain Stimulation of the Ventral Intermediate and Ventro-Oral Internus Nuclei: A Case Report and Literature Review of Dystonic Head Tremor.

Head tremor in patients with dystonia is referred to as dystonic tremor. During surgical treatment, numerous targets may be selected, including the internal segment of the globus pallidus and the ventral intermediate (Vim) nucleus; however, there is no consensus concerning the most effective treatment target. We report herein a case of dystonic head tremor in which improvement persisted for 5 years after deep brain stimulation (DBS) of the bilateral thalamic Vim and ventro-oral internus (Voi) nuclei. The patient, a 67-year-old woman, has a horizontal head tremor associated with cervical dystonia that had been resistant to drug treatment over 3 years. Immediately following surgery, dystonia and tremor symptoms had completely improved. Voice volume declined and dysarthria occurred but improved upon adjusting the stimulation conditions. Over 5 years, both head tremor and cervical dystonia have been completely controlled, and no other obvious complications have been observed. As the Voi nucleus receives pallidothalamic projections involved in dystonia and the Vim nucleus receives cerebellothalamic projections involved in tremors, stimulating these 2 nuclei with the same electrode appears reasonable in the treatment of dystonic tremor. This case suggests that Vim-Voi DBS may be effective for treating dystonic head tremor.