Abnormal magnetic resonance imaging signal in the burr hole and the identification of the intracranial infection of a deep brain stimulation device: illustrative case.

BACKGROUND: Device infection is a critical postoperative complication in deep brain stimulation (DBS). However, intracranial infections are rare and lack specific findings, which lead to a challenging diagnosis. OBSERVATIONS: A 59-year-old female with generalized dystonia underwent bilateral globus pallidus internus and subthalamic nucleus (STN) DBS device implantation. One year earlier, a left STN-DBS extension wire disconnection was observed and replaced. The patient presented to our department because of tenderness along the extension wire that had persisted for 1 month. Magnetic resonance imaging (MRI) of the head indicated abnormal signals around the lead of the left STN and burr hole. Intraoperatively, the authors observed pus and infected granulation tissue in the burr holes. After device removal, antibiotics were administered, and the patient successfully progressed without complications. Moreover, the abnormal MRI signal disappeared. LESSONS: A characteristic abnormal MRI signal within the burr hole in DBS may suggest early infection even in the absence of other inflammatory findings. Clinicians should ensure that MRI is not limited to intracranial findings but extends beyond the extracranial space.

Additional Effect of High-output Current and/or High-duty Cycle in Vagus Nerve Stimulation for Adolescent/Adult Intractable Epilepsy.

A vagus nerve stimulation (VNS) device delivers electrical pulses to the vagus nerve at a rhythm defined by the duty cycle. The standard therapeutic range is advocated for an output current of 1.5-2.25 mA and a duty cycle of 10%. As the optimal settings vary from patient to patient, some patients may benefit from additional seizure reduction when stimulated beyond the standard range. A total of 74 patients (15 children aged <12 years and 59 adolescents/adults) who underwent VNS implantation between 2011 and 2020 and who were followed up for at least 2 years were included in this retrospective study. Stimulation parameters exceeding 2.25 mA of output current, 25% of duty cycle, and 0.5625 (2.25 mA × 25%) of current × duty cycle were defined as high stimulation. The proportion achieved an additional seizure reduction of 20%, and the 50% seizure reduction rate at the last follow-up was compared between adolescents/adults and children. Approximately 40% of patients in adolescents/adults treated with high stimulation experienced an additional acute effect, resulting in a 50% or greater reduction in seizures in almost all patients. Moreover, in adolescents/adults, 22.2%-41.9% of the patients were treated with high stimulation, and the responder rate was 69.5%. Conversely, the responder rate in children was 26.7%, significantly worse than that in adolescents/adults, despite higher stimulation. VNS with high-stimulation settings is effective for adolescent and adult patients with intractable epilepsy. Even high stimulation may not be effective in extremely refractory pediatric epilepsy with a high seizure frequency.

Bilateral Magnetic Resonance Imaging-Guided Focused Ultrasound Thalamotomy for Essential Tremor.

INTRODUCTION: Essential tremor is the most common movement disorder in adults. Bilateral symptoms are typical; however, bilateral thalamotomy for essential tremor is associated with a high probability of adverse events. We retrospectively investigated the efficacy and safety of staged bilateral ventral intermediate nucleus thalamotomy for refractory essential tremor using magnetic resonance imaging-guided focused ultrasound. METHODS: We enrolled 5 consecutive patients with refractory essential tremor between September 2016 and March 2020. Patients underwent a second operation at least 1 year after the first operation. The second lesion was created asymmetrically to the first lesion. RESULTS: Mean patient age was 57.6 years, and the mean interval between the 2 operations was 27.8 months. The second lesion center was superior to the first lesion in all patients. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor total scores were 63.6, 49.2, and 21.8, respectively. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor part C scores were 18.4, 8.2, and 2.6, respectively. One patient had permanent adverse events of slight dysarthria and discomfort in the tongue. No patient experienced dysphagia or cognitive dysfunction after the second operation. Four of the 5 patients were satisfied with the results of the bilateral treatment, including the patient who had permanent adverse events. CONCLUSIONS: Magnetic resonance imaging-guided focused ultrasound is an effective method for bilateral thalamotomy when adhering to the following considerations: (1) asymmetrical lesions are created and (2) sufficient interval (>1 year) between operations.

[Basal Ganglia and Circuit Function:How Does the Ablation or Deep Brain Stimulation(DBS)Work?]

The basal ganglia(BG)is composed of four parallel loops: the motor, oculomotor, associative, and limbic loops. The motor loop starts from the cortex, travels through the BG and thalamus, and returns to the same area of the cortex with somatotopic organization. The striatum is the major input nucleus of the cortex, and the internal segment of the globus pallidus(GPi)is the main output nucleus. BG is explained by the direct and indirect pathways, and these excitatory or inhibitory pathways are used for several disease models. In Parkinson's disease(PD), dopamine deficiency acts on both direct and indirect pathways to cause the neuronal activity of GPi to becomes disinhibited. Pallidotomy, an effective surgery to improve Parkinsonism, aimed to destroy this hyperactive state. This is based on the rate model. However, a simian PD model with MPTP-treated monkeys exhibited increased GPi activity during effective stimulation of subtalamic nucleus(STN)-DBS, which makes it difficult to explain the pathophysiology of PD based only on the rate model. Instead, the alterative model is now widely prevailing. Local field potentials recorded from the DBS leads implanted in GPi and/or STN uncovered the abnormally synchronized activity in the ß range(ß oscillation)and abnormal co-synchronization between these nuclei, which is believed to be important in the pathophysiology of PD.

Cough syncope and hyperventilation-induced convulsion in Chiari 1.5 malformation.

Chiari malformation type I (CM1) is defined as cerebellar tonsillar herniation below the level of the foramen magnum. Syncope, especially cough syncope, is a rare but important symptom of CM1 patients. Here, we report a CM1 patient, in combination with brainstem herniation (CM1.5), presenting with repetitive syncope who was successfully treated by decompressive surgery. A 43-year-old right-handed male, with 5-year history of repeated episodes of loss of consciousness in association with cough, was investigated. Neurological examination revealed slight muscle weakness, clumsiness, and sensory disturbance in the left upper limb. There was no sign of orthostatic hypotension or orthostatic intolerance. Cranial and spinal magnetic resonance imaging revealed a herniation of the cerebellar tonsils and a syringomyelia. Forced hyperventilation during electroencephalogram (EEG) induced brief generalized symmetric clonic convulsions with preserved consciousness, but no overt EEG seizure patterns or slow activities were found. Based on the diagnosis of CM1.5 with recurrent episodes of loss of consciousness, he underwent foramen magnum decompression. He has no recurrence of the episode after the surgery on 1 year follow-up. Decompressive surgery was an effective procedure for cough syncope and other symptoms of the current patient with CM1.5. Dissociation of cerebrospinal fluid pressure between the cranial and spinal compartments which leads further herniation of the cerebellar tonsils and subsequent compression on the cerebellum and the brainstem is considered to be the major mechanism of his cough syncope. Analysis of EEG can be useful not only to diagnose epileptic seizures but also to elucidate mechanisms of syncope and concurrent involuntary movements.

Focused Ultrasound Thalamotomy for Refractory Essential Tremor: A Japanese Multicenter Single-Arm Study.

BACKGROUND: Several feasibility studies and a randomized, controlled, multicenter trial have demonstrated the safety and efficacy of unilateral transcranial magnetic resonance-guided focused ultrasound (FUS) lesioning of the ventral intermediate thalamic nucleus in treating essential tremor. OBJECTIVE: To evaluate the safety and efficacy of FUS thalamotomy in a Japanese patient cohort through a prospective, multicenter, single-arm confirmatory trial. METHODS: A total of 35 patients with disabling refractory essential tremor underwent unilateral FUS thalamotomy and were followed up for 12 post-treatment months. Safety was measured as the incidence and severity of treatment-related adverse events. Efficacy was measured as the tremor severity and quality of life improvements using the Clinical Rating Scale for Tremor and Questionnaire for Essential Tremor. RESULTS: The mean skull density ratio (SDR) was 0.47. There was a significant decrease in the mean postural tremor score of the treated hand from baseline to 12 mo by 56.4% (95% CI: 46.7%-66.1%; P < .001), which was maintained at last follow-up. Quality of life improved by 46.3% (mean overall Questionnaire for Essential Tremor score of 17.4 [95% CI: 12.1-22.7]) and there were no severe adverse events. The most frequent adverse event was gait disturbance and all events resolved. CONCLUSION: Unilateral FUS thalamotomy allowed significant and sustained tremor relief and improved the quality of life with an outstanding safety profile. The observed safety and efficacy of FUS thalamotomy were comparable to those reported in a previous multicenter study with a low SDR, and inclusion of the low SDR group did not affect effectiveness.

Deep slow nasal respiration with tight lip closure for immediate attenuation of severe tics.

BACKGROUND: Severe intractable tics, which are associated with Tourette syndrome and chronic tic disorder (TS/CTD), severely affect the quality of life. Common less-invasive treatments are often unable to attenuate tics with deep brain stimulation currently being the only effective treatment. We aimed to assess the anti-tic effect of deep slow nasal respiration with tight lip closure using patients with TS/CTD. METHODS: We retrospectively analyzed 10 consecutive patients (9 men, 1 woman; 23-41 years old). We instructed the patients to perform the procedure for 120 s and to obtain a video recording of before and during the procedure. The videos were used to count tics and determine lip competency or incompetency. The counted tics were rated using the modified Rush Video Rating Scale. RESULTS: Compared with before the procedure, there were significantly lower frequencies of motor and phonic tics, as well as video scored, during the procedure. Eight patients presented with lip incompetency before the procedure and none after the procedure (P = 0.041). There were no side effects associated with the procedure. CONCLUSION: Our findings indicate that deep slow nasal respiration with tight lip closure ameliorates tics in patients with TS/CTD. In accordance with our results, lip opening and oral breathing could be causes of tics, in addition to heritability. Therefore, this novel procedure could improve tics. Furthermore, our findings could contribute toward the development of tic treatments and elucidate their pathophysiology regarding the reward system, hypersensitivity, autonomic nerves, and nasal airway.

What factors impact the clinical outcome of magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor?

OBJECTIVE: Magnetic resonance imaging-guided focused ultrasound (MRgFUS) is a novel and useful treatment for essential tremor (ET); however, the factors impacting treatment outcome are unknown. The authors conducted this study to determine the factors affecting the outcome of MRgFUS. METHODS: From May 2016 through August 2017, 15 patients with ET were admitted to Ohnishi Neurological Center and treated with MRgFUS. To determine the factors impacting treatment outcome, the authors retrospectively studied correlations between the Clinical Rating Scale for Tremor (CRST) improvement rate and age, disease duration, baseline CRST score, skull density ratio (SDR), skull volume, maximum delivered energy, or maximum temperature. RESULTS: The mean CRST score was 18.5 ± 5.8 at baseline and 4.6 ± 5.7 at 1 year. The rate of improvement in the CRST score was 80% ± 22%. Younger age and lower baseline CRST score were correlated with a higher CRST improvement rate (p = 0.025 and 0.007, respectively). To obtain a CRST improvement rate ≥ 50%, a maximum temperature ≥ 55°C was necessary. There was no correlation between SDR and CRST improvement rate (p = 0.658). A lower SDR and higher skull volume required significantly higher maximum delivered energy (p = 0.014 and 0.016, respectively). A higher maximum temperature was associated with a significantly larger lesion volume (p = 0.026). CONCLUSIONS: Younger age and lower baseline CRST score were favorable outcome factors. It is important to assess predictive factors when applying MRgFUS.

Impact of skull density ratio on efficacy and safety of magnetic resonance-guided focused ultrasound treatment of essential tremor.

OBJECTIVE: Skull density ratio (SDR) assesses the transparency of the skull to ultrasound. Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy in essential tremor (ET) patients with a lower SDR may be less effective, and the risk for complications may be increased. To address these questions, the authors analyzed clinical outcomes of MRgFUS thalamotomy based on SDRs. METHODS: In 189 patients, 3 outcomes were correlated with SDRs. Efficacy was based on improvement in Clinical Rating Scale for Tremor (CRST) scores 1 year after MRgFUS. Procedural efficiency was determined by the ease of achieving a peak voxel temperature of 54°C. Safety was based on the rate of the most severe procedure-related adverse event. SDRs were categorized at thresholds of 0.45 and 0.40, selected based on published criteria. RESULTS: Of 189 patients, 53 (28%) had an SDR < 0.45 and 20 (11%) had an SDR < 0.40. There was no significant difference in improvement in CRST scores between those with an SDR ≥ 0.45 (58% ± 24%), 0.40 ≤ SDR < 0.45 (i.e., SDR ≥ 0.40 but < 0.45) (63% ± 27%), and SDR < 0.40 (49% ± 28%; p = 0.0744). Target temperature was achieved more often in those with an SDR ≥ 0.45 (p < 0.001). Rates of adverse events were lower in the groups with an SDR < 0.45 (p = 0.013), with no severe adverse events in these groups. CONCLUSIONS: MRgFUS treatment of ET can be effectively and safely performed in patients with an SDR < 0.45 and an SDR < 0.40, although the procedure is more efficient when SDR ≥ 0.45.

Impact of parameters of radiofrequency coagulation on volume of stereotactic lesion in pallidotomy and thalamotomy.

BACKGROUND: One of the many reasons why lesional surgery for movement disorders has been more or less abandoned may have been the difficulty in predicting the shape and size of the stereotactic radiofrequency (RF) lesion. OBJECTIVES: To analyse the contribution of various RF coagulation parameters towards the volume of pallidotomies and thalamotomies. METHODS: The relationship between temperature of coagulation, length of coagulated area and duration of coagulation on the one hand, and lesion volume on the other was retrospectively evaluated. Lesion diameters were measured on stereotactic thin-slice CT and MRI scans, and volumes of lesions were calculated concerning 36 pallidotomies and 14 thalamotomies in 46 patients who were operated using the same RF generator and same RF electrode. RESULTS: The coagulation temperature, length of coagulated area and duration of coagulation were all correlated to the lesion volume. However, for a given length of coagulated area, the lesion´s size was most strongly influenced by the temperature. Despite this clear correlation, and the relatively homogenous coagulation parameters, the lesions' volumes were markedly scattered. CONCLUSIONS: The volume of the stereotactic RF lesions could be correlated with the coagulation parameters, especially the temperature, at a group level, but could not be predicted in individual patients based solely on the RF coagulation parameters.

[Adequate dose of intrathecal baclofen therapy for spasticity].

Baclofen, a gamma-aminobutyric acid receptorB, agonist, is used to reduce symptoms of spasticity (hyperreflexia, increases in muscle tone, involuntary muscle activity), but the adequate baclofen dose in each diseases is unclear. The aim of our study was to evaluate how dosage level improves the symptoms of spasticity. 25 weeks observational longitudinal follow up study assessed 16 patients who received intrathecal baclofen given by a programmable pump. Clinical efficacy was assessed by the Ashworth scale related with the dose of baclofen. Compared with pretreatment values, there was an improvement in clinical efficacy, but the baclofen dose needed for hereditary spastic paraplegia (HSP) was significantly smaller than that in other diseases. The result shows the importance of knowledge of the adequate baclofen dose in each disease in that baclofen causes some clinically significant adverse reactions.

[A case report of familial AVM].

Genetic analysis of the familials of patients with arteriovenous malformation (AVM) has a significant potential to reveal the etiology of this disease, although neither the detailed etiology nor pathogenesis of AVM has been fully elucidated to date. While a history of AVM is apparent in 2% of stroke patients, familial occurrence of AVM is very rare. We describe an interesting familial case of AVM. This also represents a rare pattern of familial occurrence in that patients are not likely hereditary hemorrhagic telangiectasia (HHT). There is a possibility that such familial AVMs are associated with unknown genes other than HHT genes.

[Symptomatic radiation necrosis 10 years after gamma knife surgery for arteriovenous malformations: a case report].

We present a case of symptomatic radiation necrosis after gamma knife surgery for arteriovenous malformations (AVMs). Initially, at the age of 30 years the patient was treated with gamma knife surgery. Angiography performed 2 years after radiation therapy revealed that the AVMs were completely obliterated. Five years later, the patient had a generalized convulsion and a computed tomography (CT) scan showed a cystic formation in the irradiated area. The patient was treated with a cyst-peritoneal (CP) shunt. Thereafter, the patient seemed to be cured, but 5 years after CP shunt treatment, the patient had right hemiparesis, agraphia, and right hemianopsia. Magnetic resonance imaging (MRI) revealed radiation necrosis in the left parietooccipital region and midline shift of the brain. The patient was operated on and the hyalinized nidus and CP shunt tube were removed. The patient fully recovered from the symptoms and resumed work.

Orbital schwannoma extending to the lateral wall of the cavernous sinus through the superior orbital fissure--case report.

A 58-year-old man presented with a rare orbitocavernous sinus schwannoma that originated from the orbital opthalmic nerve, and manifested as slowly progressive hypesthesia of the right side of the forehead, proptosis, and ocular pain with rapidly worsening visual acuity. Magnetic resonance imaging revealed a huge orbital tumor extending to the lateral wall of the cavernous sinus through the superior orbital fissure. Microsurgical total resection of the tumor was achieved using an epidural orbitofrontal approach with orbito-fronto-zygomatic craniotomy. The histological diagnosis was schwannoma with Antoni type A formation. The postoperative course was uneventful except for the hypesthesia on the right side of the forehead and transient oculomotor paralysis. Surgery was effective to relieve the symptoms and improve the activities of daily living.

Treatment of Parkinson's disease model mice with allogeneic embryonic stem cells: necessity of immunosuppressive treatment for sustained improvement.

OBJECTIVE: The purpose of the present study was to examine the efficacy of transplantation of mouse embryonic stem (ES) into Parkinson's disease (PD) model mice as well as the necessity of immunosuppression in allogeneic donor-host combinations. MATERIALS AND METHODS: ES cells, derived from SvJ129 strain mice, were differentiated into tyrosine hydroxylase (TH)-positive neurons in vitro by an embryoid body (EB)-based multistep differentiation method and used as graft cells for PD mice, which were prepared by injection of 6-hydroxydopamine (OHDA) into C57BL/6, BALB/c and C3H/HeN strains. Mice from each strain were divided into Groups 1-3. Four weeks after the 6-OHDA injection, Group 1 received phosphate-buffered saline in the striatum wounds, while Group 2 received 2 x 10(4) graft cells, and Group 3 mice received 2 x 10(4) graft cells and were also treated with cyclosporine A. RESULTS: Apomorphine-induced rotational behavior was improved in Groups 2 and 3, but not in Group 1. However, the behavioral improvement ceased later in Group 2, whereas sustained improvement was observed in Group 3 throughout the 8 week observation period after transplantation. ES-derived TH(+) cells were found at the grafted sites at the end of the experiment in Groups 2 and 3, and tended to be more abundant in Group 3. CONCLUSION: Intra-striatum transplantation of ES-derived dopaminergic neurons was effective in treating PD mice, even in allogeneic donor-host combinations. Immunosuppressive treatment did not have an effect on initial behavioral restoration after transplantation; however, it was necessary for sustained improvement over a prolonged period.

[Case report of intrathecal baclofen administration in a child with severe spasticity attributable to traumatic brain injury].

We report a pediatric case of intrathecal baclofen therapy for severe spasticity following traumatic brain injury. A 14-year-old boy suffered from traumatic brain injury by traffic accident in 2005. Subsequently, he experienced tetraparesis and severe spasticity with spontaneous spasms. He underwent baclofen screening test, and his spasticity was improved. Thereafter intrathecal baclofen therapy was performed. Following baclofen pump implantation, Ashworth Score decreased from 4.0 points to 3.0 in lower limbs, and from 3.0 to 1.5 in upper limbs. His muscle tone was reduced and occurrence of spontaneous spasms stopped. Intrathecal baclofen therapy was observed to be an effective treatment for severe spasticity in childhood. Since children receiving the therapy demonstrated longer survival period than adults, long-term follow-up of this therapy is warranted.

[A case of brain metastasis of renal pelvic carcinoma].

A 68-year-old woman was referred t o our urological department with the complaint of hematuria and right abdominal mass. Contrast-enhanced computed tomography (CT) revealed renal tumor and multiple lung metastases. Right nephroureterectomy was performed. Pathological examination was transitional cell carcinoma. After nephroureterectomy, combination chemotherapy consisting of methotrexate, doxorubicin and cisplatin was performed. Oral administration of tegafur was continued outside the hospital. Eight months after the nephroureterectomy, she suffered from left hemiconvulsion and was transferred to our hospital. Contrast-enhanced CT of the head revealed a heterogeneous enhancement tumor in the parietal lobe. Surgical resection was performed by right parietal craniotomy. Because the tumor was invasive in the superior sagittal sinus, subtotal removal of the tumor was performed. Pathological examination indicated transitional cell carcinoma the same feature as in the renal pelvis. After surgical resection, she was treated by gamma knife stereotactic radiosurgery. She returned to ordinary life, but 7 months later tumor recurrence took place. Repeated surgical resection and stereotactic radiosurgery was performed, but she died 44 months after the initial nephroureterectomy due to the relapse of brain metastasis. Brain metastasis of renal pelvic carcinoma is extremely rare, and we have found only three case reports. We describe the course of our patient, and review the three cases of brain metastasis of renal pelvic carcinoma that are in the literature.