Estimulação cerebral profunda para o tratamento da distonia primária generalizada e distonia cervical / Deep brain stimulation for the treatment of primary generalized dystonia and cervical dystonia

INTRODUÇÃO: A distonia é um distúrbio neurológico caracterizado por contrações musculares involuntárias, responsáveis por posturas e movimentos anormais. Sua expressão clínica é determinada pela gravidade e distribuição dos músculos envolvidos, desde variações focais e segmentares mais leves, a casos mais graves de manifestação generalizada. No Brasil, no âmbito do Sistema Único de Saúde (SUS), há um Protocolo Clínico e Diretrizes Terapêuticas sobre o cuidado de Distonia e Espasmo Hemifacial que preconiza a utilização da Toxina Botulínica Tipo A (TBA). A estimulação cerebral profunda (Deep Brain Stimulation - DBS) é um procedimento cirúrgico utilizado no tratamento de várias doenças neurológicas, normalmente em casos refratários à terapia usual. A DBS consiste na implantação de um dispositivo médico para fornecer estimulação elétrica a regiões específicas do cérebro. Tendo em vista que existem produtos de saúde aprovados pela Anvisa para realização da DBS e que o procedimento já está disponível no SUS para determinadas condições, o presente relatório foi desenvolvido com o objetivo de compreender a viabilidade de ampliação de uso desse procedimento no SUS para o tratamento de distonia primária generalizada e distonia cervical. PERGUNTA DE PESQUISA: O uso da DBS é eficaz, seguro e custo-efetivo para o tratamento de distonia primária generalizada e distonia cervical em pacientes adultos e pediátricos refratários ao tratamento convencional? EVIDÊNCIAS CLÍNICAS: Foi realizada uma revisão sistemática a partir de buscas nas bases de dados MEDLINE (via Pubmed), EMBASE, Cochrane Library, LILACS, IBECS, BRISA (via BVS), considerando o tratamento de distonia primária generalizada e distonia cervical com o procedimento de estimulação cerebral profunda. Foram estabelecidos critérios de elegibilidade abrangentes devido à escassez de estudos disponíveis na literatura científica. Os estudos foram avaliados quanto ao risco de viés com a ferramenta Cochrane Risk of Bias Tool ­ ROB 2.0 para Ensaio Clínico Randomizado (ECR) e a ferramenta Risk of Bias in Non-Randomised Studies of Interventions (ROBINS-I) para os estudos observacionais. A qualidade geral da evidência foi avaliada utilizando a abordagem GRADE (Grading of Recommendatons Assessment, Development and Evaluaton). Para distonia primária generalizada, foram incluídos 17 estudos que envolveram 350 pacientes, entre crianças e adultos. Entre os estudos identificados um era ensaio clínico randomizado (ECR) que comparou DBS e sham; os demais estudos eram ensaios clínicos não randomizados (n=4) ou observacionais (estudos de coorte (n=10) e séries de casos (n=2). O ECR analisado incluiu tanto crianças quanto adultos e avaliou no total 40 pacientes. Os resultados apresentados foram positivos na redução do comprometimento motor (redução de 39,3%) e da incapacidade (redução de 37,5%) em pacientes que realizaram a DBS, avaliados pela escala Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). é importante destacar a consistência em relação aos resultados sempre mostrarem benefício e a magnitude do efeito, que é relevante clinicamente. Os estudos observacionais incluídos também sugerem resultados positivos com o uso da DBS, com qualidade geral da evidência variando de baixa a muito baixa devido ao risco de viés grave ou crítico, principalmente pela presença de potenciais fatores de confundimento e/ou problemas relacionados ao cegamento (ausência de descrição ou relato inadequado). Para distonia cervical, foram incluídos 13 estudos que envolveram 300 pacientes, a maioria dos estudos incluindo apenas adultos. Entre os estudos identificados um era ECR comparando a DBS com procedimento sham; os demais estudos clínicos eram não randomizados (n=2) ou observacionais (estudos de coorte (n=9) e caso-controle (n=1). O ECR avaliou 62 pacientes adultos e os resultados, avaliados pela escala Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), indicam que a DBS reduz o comprometimento motor (redução média de 5,1 pontos), incapacidade (redução média de 5,6 pontos) e dor (redução média de 4,4 pontos) em pacientes com distonia cervical refratária ao tratamento farmacológico quando comparado com a estimulação simulada. Novamente é importante ressaltar que os resultados foram clinicamente relevantes e observou-se consistência entre os achados no ECR e nos demais estudos. Os estudos observacionais incluídos também relatam resultados positivos com o uso da DBS. AVALIAÇÃO ECONÔMICA: A razão de custo-efetividade incremental da ampliação de uso da DBS foi de R$ 4.378,58 por QALY na distonia generalizada e de R$46.119,11 por QALY na distonia cervical, com a maior parte dos resultados demonstrando superioridade clínica da tecnologia avaliada na análise de sensibilidade. Pela análise de sensibilidade probabilística, 95% dos valores de RCEI estão abaixo de R$7.000 para a distonia generalizada e abaixo de R$1.000.000,00 para a cervical. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: Estima-se que 945 pessoas possuem distonia generalizada e 10.698 distonias cervical no Brasil e que 482 pacientes sejam passíveis de serem tratados com DBS em 2022. Considerando a participação de mercado do procedimento, 72 pacientes fariam a DBS em 2022, 124 em 2023, 131 em 2024, 98 em 2025 e 55 em 2026. Isso corresponde, em uma ampliação de uso progressiva, um impacto orçamentário de, aproximadamente, R$7.710.181,32 em 5 anos. MONITORAMENTO DO HORIZONTE TECNOLÓGICO: No Monitoramento do Horizonte Tecnológico foram encontradas 2 novas tecnologias com registros ANVISA e FDA (Percept PC Brain Sense e Vercise Genus). Em relação aos depósitos e patentes concedidas foi possível evidenciar 1 documento patentário, com depósito em 2021, referente a métodos e sistemas para estimulação cerebral profunda focalizada não invasiva. CONSIDERAÇÕES FINAIS: As evidências disponíveis para a comparação entre DBS e estimulação simulada para os tipos de distonia avaliadas foram baseadas apenas em dois ECRs. Os resultados dos ECRs mostraram resultados favoráveis à intervenção. Os estudos observacionais identificados, ainda que apresentem limitações metodológicas, também apoiam os resultados dos ECRs avaliados. Como o cuidado da distonia em casos refratários ao tratamento usual carece de alternativas terapêuticas é possível que os pacientes com distonia já façam uso desse procedimento por meio dos CIDs do grupo R (R250, R251, R252, R253 e R258), para os quais o procedimento já está disponível no SUS. RECOMENDAÇÃO PRELIMINAR: os membros presentes no Plenário da Conitec, em sua 110ª Reunião Ordinária, realizada no dia 06 de julho de 2022, deliberaram que a matéria fosse disponibilizada em consulta pública com recomendação preliminar favorável à ampliação de uso da estimulação cerebral profunda para o tratamento da distonia. Para essa recomendação, a Conitec considerou que as evidências acerca da eficácia e segurança do procedimento são escassas, mas provém de ensaios clínicos randomizados com resultados clinicamente relevantes, o quadro clínico que exige seu uso seria para aqueles pacientes refratários a todos os demais tratamentos. CONSULTA PÚBLICA: Todos os participantes da CP nº 50/2022, que realizaram contribuições frente ao tema avaliado, realizada entre os dias 01/08/2022 e 22/08/2022, concordaram com recomendação preliminar da Conitec favorável à ampliação de uso da estimulação cerebral profunda para o tratamento da distonia primária generalizada e distonia cervical. Foram recebidas 23 contribuições, sendo 13 através do formulário técnico-científico e 10 através do formulário de experiência ou opinião. De forma geral, as contribuições ressaltaram os benefícios clínicos do procedimento, principalmente destacando melhora da qualidade de vida. Também comentaram a respeito do alto custo e dificuldade de acesso ao procedimento. RECOMENDAÇÃO FINAL DA CONITEC: Pelo exposto, o Plenário da Conitec, em sua 112ª Reunião Ordinária, realizada no dia 31 de agosto de 2022, deliberou por unanimidade recomendar a ampliação de uso da estimulação cerebral profunda para o tratamento da distonia primária generalizada e distonia cervical em pacientes refratários a terapia convencional. Os membros da Conitec consideraram os benefícios proporcionados pelo procedimento e a necessidade de uso para aqueles pacientes refratários aos demais tratamentos. A consulta pública não trouxe elementos para mudança da recomendação preliminar. Por fim, foi assinado o Registro de Deliberação nº 767/2022. DECISÃO: de ampliar o uso, no âmbito do Sistema Único de Saúde - SUS, da estimulação cerebral profunda para o tratamento de distonias, conforme protocolo estabelecido pelo Ministério da Saúde, conforme a Portaria nº 108, publicada no Diário Oficial da União nº 192, seção 1, página 61, em 7 de outubro de 2022.

Device profile of the percept PC deep brain stimulation system for the treatment of Parkinson's disease and related disorders.

INTRODUCTION: Several software and hardware advances in the field of deep brain stimulation (DBS) have been realized in recent years and devices from three manufacturers are available. The Percept™ PC platform (Medtronic, Inc.) enables brain sensing, the latest innovation. Clinicians should be familiar with the differences in devices, and with the latest technologies to deliver optimized patient care.Areas covered: In this device profile, the sensing capabilities of the Percept™ PC platform are described, and the system capabilities are differentiated from other available platforms. The development of the preceding Activa™ PC+S research platform, an investigational device to simultaneously sense brain signals and provide therapeutic stimulation, is provided to place Percept™ PC in the appropriate context.Expert opinion: Percept™ PC offers unique sensing and diary functions as a means to refine therapeutic stimulation, track symptoms and correlate them to neurophysiologic characteristics. Additional features enhance the patient experience with DBS, including 3 T magnetic resonance imaging compatibility, wireless telemetry, a smaller and thinner battery profile, and increased battery longevity. Future work will be needed to illustrate the clinical utility and added value of using sensing to optimize DBS therapy. Patients implanted with Percept™ PC will have ready access to future technology developments.

Eficacia y seguridad del dispositivo electrodos para estimulación cerebral profunda para pacientes con enfermedad de Parkinson avanzado / Efficacy and safety of the deep brain stimulation electrode device for patients with advanced Parkinson's disease

INTRODUCCIÓN: Este documento técnico se realiza a solicitud del Instituto Nacional de Ciencias Neurológicas. a. Cuadro clínico La enfermedad de Parkinson (EP) es una enfermedad degenerativa progresiva que se caracteriza por temblor de reposo, rigidez, bradicinesias e inestabilidad postural. Se produce por la muerte de neuronas dopaminérgicas en la sustancia negra, tracto extrapiramidal del cerebro medio, además de acumulación de proteínas en el sistema nervioso central, autonómico y periférico. Las nuevas terapias de tratamiento se enfocan en estrategias no dopaminérgicas que permitan controlar o eliminar las complicaciones motoras o proporcionan un estímulo dopaminérgico más fisiológico. b. Tecnología sanitaria La estimulación cerebral profunda (ECP) es un tratamiento indicado en pacientes con complicaciones motoras en la EP. La técnica consiste en la colocación quirúrgica de guías transcraneales en áreas específicas que controlan el movimiento, en el núcleo subtalámico (NST) o globo pálido interno (GPi), y que se unen a una batería en el pecho, similar a la de un marcapaso. Su función es liberar estímulos eléctricos, por medio de los cuales bloquearía señales anormales que causan los síntomas motores de la EP. OBJETIVO Evaluar la eficacia y seguridad del dispositivo electrodos para estimulación cerebral profunda para pacientes con enfermedad de Parkinson avanzado. METODOLOGÍA: Se realizó una búsqueda en las principales bases de datos bibliográficas: MEDLINE, LILACS, COCHRANE, así como en buscadores genéricos de Internet incluyendo Google Scholar y TRIPDATABASE. Adicionalmente, se hizo una búsqueda dentro de la información generada por las principales instituciones internacionales de neurología, y agencias de tecnologías sanitarias que realizan revisiones sistemáticas (RS), evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC). RESULTADOS: Se seleccionaron dos RS, cuatro GPC y tres ETS. No se encontraron evaluaciones de económicas de Perú o de la región acerca de la tecnología de interés. Una RS (2018) evaluó la eficacia y seguridad de la ECP para el tratamiento de la EP. La búsqueda incluyó 8 ECAs de diseño paralelo (N=1189, edad media=59.6, excepto por 2 estudios con reclutamiento temprano) hasta la mayo del 2018. Los objetivos primarios para eficacia fueron: discapacidad según la escala UPDRS, calidad de vida, reducción en la dosis de levodopa; y los objetivos secundarios para seguridad fueron: pacientes con eventos adversos (EAs) y número total de EAs. Los comparadores fueron ECP de cualquier tipo comparado con mejor terapia médica. El UPDRS mejoró significativamente para el grupo de ECP en comparación al grupo de mejor terapia médica (-5.14 (-6.18, -4.10); P < 0.00001). Se disminuyó la dosis de levodopa significativamente en el grupo de ECP comparado al grupo de terapia médica (-418.25, (-570.48, -266.02); P < 0.00001. El riesgo de que un paciente experimente un EA fue significativamente mayor en el grupo de ECP en comparación al grupo de tratamiento médico ((2.12 (1.26, 3.59); P = 0.005). En el 2018 se publicó una RS para comparar la eficacia de ECP de acuerdo con la localización del estímulo ya sea NST o GPi. La búsqueda se realizó hasta marzo del 2017, incluyendo 5 ECAs (N=3267, edad media = 59.1). Se investigó el objetivo primario según la parte 3 del UPDRS para evaluación de temblor. Al comparar por localización (NST vs GPi) no se encontró diferencias. De la misma forma no se vio una asociación del efecto de la medicación dopaminérgica en la eficacia del ECP. Además, se evaluaron los subscores post-ECP en NST o en el GPi, cada una de las 5 sesiones post-ECP fueron significativos con disminución de temblores, pero no se mostró diferencia entre los grupos. Dos GPC (España 2012, México 2010) consideran ECP ya sea del NST o GPpi como una opción eficaz para pacientes con EP. Una de estas GPC (España 2012) menciona adicionalmente que, aunque ECP del NST sea elegido en la mayoría de los casos, se debe considerar el GPi en pacientes seleccionados (menor umbral de discinesias o mayor riesgo de deterioro anímico o cognitivo). Una GPC (Chile 2010) no menciona ECP como una opción para el manejo de EP. Dos ETS (Brasil 2019, Irlanda 2012) recomiendan el uso de ECP ya sea del NST o GPi comparado con el tratamiento médico estándar dado que mejora la calidad de vida y la función motora por lo que estas son incluidas dentro de sus políticas de cobertura. Una ETS (Canadá 2005) no encuentra evidencia concluyente acerca de sus beneficios por lo que se requiere estudios más rigurosos. CONCLUSIONES: La evidencia con respecto a ECP en EP es moderada. Basados en RS de ECAs, se evidencia que existe beneficios clínicos de ECP comparado con tratamiento médico estándar como mejora de la discapacidad y calidad de vida. Al compararse de acuerdo con el lugar de estimulación no se encuentran diferencias entre NST o GPi. En general, los documentos de GPC y ETS recomiendan a la tecnología para el manejo de EP.

Economic evaluation of deep-brain stimulation for Tourette's syndrome: an initial exploration.

BACKGROUND: Deep-brain stimulation (DBS) can be effective in controlling medically intractable symptoms of Tourette's syndrome (TS). There is no evidence to date, though, of the potential cost-effectiveness of DBS for this indication. OBJECTIVE: To provide the first estimates of the likely cost-effectiveness of DBS in the treatment of severe TS. METHODS: We conducted a cost-utility analysis using clinical data from 17 Australian patients receiving DBS. Direct medical costs for DBS using non-rechargeable and rechargeable batteries and for the alternative best medical treatment (BMT), and health utilities for BMT were sourced from the literature. Incremental cost-effectiveness ratios (ICERs) were estimated using a Markov models with a 10-year time horizon and 5% discount rate. RESULTS: DBS increased quality-adjusted life year (QALY) gained from 2.76 to 4.60 over a 10-year time horizon. The ICER for DBS with non-rechargeable (rechargeable) batteries, compared to BMT, was A$33,838 (A$15,859) per QALY. The ICER estimates are sensitive to DBS costs and selected time horizon. CONCLUSIONS: Our study indicates that DBS may be a cost-effective treatment for severe TS, based on the very limited clinical data available and under particular assumptions. While the limited availability of data presents a challenge, we also conduct sensitivity analyses to test the robustness of the results to the assumptions used in the analysis. We nevertheless recommend the implementation of randomised controlled trials that collect a comprehensive range of costs and the use of a widely accepted health-related quality of life instrument to enable more definitive statements about the cost-effectiveness of DBS for TS.

Pulse generator battery life in deep brain stimulation: out with the old in with the less durable?

BACKGROUND: Battery life of the most commonly used implantable pulse generators in deep brain stimulation is limited. Device replacement is costly and may expose patients to additional risks. Driven by the observation that in our experience newer generation devices seemed to need earlier replacement than the older generation, we aimed to retrospectively analyze the battery life of two generations of non-rechargeable devices, manufactured by a single company (Medtronic, USA). METHODS: Battery life of 281 devices in 165 patients was taken into account for data analysis. This represented 243 older generation devices (Kinetra and Soletra) and 38 newer generation devices (Activa). RESULTS: The battery life of older generation stimulators was 2-fold longer than the newer generation. CONCLUSIONS: Newer devices are more versatile than the older generation. Their battery life is however significantly shorter. Development of next-generation devices needs to address this issue in order to limit health risks and reduce financial costs.

3-Tesla MRI of deep brain stimulation patients: safety assessment of coils and pulse sequences.

OBJECTIVE: Physicians are more frequently encountering patients who are treated with deep brain stimulation (DBS), yet many MRI centers do not routinely perform MRI in this population. This warrants a safety assessment to improve DBS patients' accessibility to MRI, thereby improving their care while simultaneously providing a new tool for neuromodulation research. METHODS: A phantom simulating a patient with a DBS neuromodulation device (DBS lead model 3387 and IPG Activa PC model 37601) was constructed and used. Temperature changes at the most ventral DBS electrode contacts, implantable pulse generator (IPG) voltages, specific absorption rate (SAR), and B1+rms were recorded during 3-T MRI scanning. Safety data were acquired with a transmit body multi-array receive and quadrature transmit-receive head coil during various pulse sequences, using numerous DBS configurations from "the worst" to "the most common."In addition, 3-T MRI scanning (T1 and fMRI) was performed on 41 patients with fully internalized and active DBS using a quadrature transmit-receive head coil. MR images, neurological examination findings, and stability of the IPG impedances were assessed. RESULTS: In the phantom study, temperature rises at the DBS electrodes were less than 2°C for both coils during 3D SPGR, EPI, DTI, and SWI. Sequences with intense radiofrequency pulses such as T2-weighted sequences may cause higher heating (due to their higher SAR). The IPG did not power off and kept a constant firing rate, and its average voltage output was unchanged. The 41 DBS patients underwent 3-T MRI with no adverse event. CONCLUSIONS: Under the experimental conditions used in this study, 3-T MRI scanning of DBS patients with selected pulse sequences appears to be safe. Generally, T2-weighted sequences (using routine protocols) should be avoided in DBS patients. Complementary 3-T MRI phantom safety data suggest that imaging conditions that are less restrictive than those used in the patients in this study, such as using transmit body multi-array receive coils, may also be safe. Given the interplay between the implanted DBS neuromodulation device and the MRI system, these findings are specific to the experimental conditions in this study.

Reduced long-term cost and increased patient satisfaction with rechargeable implantable pulse generators for deep brain stimulation.

OBJECTIVE: Deep brain stimulation (DBS) has revolutionized the treatment of neurological disease, but its therapeutic efficacy is limited by the lifetime of the implantable pulse generator (IPG) batteries. At the end of the battery life, IPG replacement surgery is required. New IPGs with rechargeable batteries (RC-IPGs) have recently been introduced and allow for decreased reoperation rates for IPG replacements. The authors aimed to examine the merits and limitations of these devices. METHODS: The authors reviewed the medical records of patients who underwent DBS implantation at their institution. RC-IPGs were placed either during initial DBS implantation or during an IPG change. A cost analysis was performed that compared RC-IPGs with standard IPGs, and telephone patient surveys were conducted to assess patient satisfaction. RESULTS: The authors identified 206 consecutive patients from 2011 to 2016 who underwent RC-IPG placement (mean age 61 years; 67 women, 33%). Parkinson's disease was the most common indication for DBS (n = 144, 70%), followed by essential tremor (n = 41, 20%), dystonia (n = 13, 6%), depression (n = 5, 2%), multiple sclerosis tremor (n = 2, 1%), and epilepsy (n = 1, 0.5%). DBS leads were typically placed bilaterally (n = 192, 93%) and targeted the subthalamic nucleus (n = 136, 66%), ventral intermediate nucleus of the thalamus (n = 43, 21%), internal globus pallidus (n = 21, 10%), ventral striatum (n = 5, 2%), or anterior nucleus of the thalamus (n = 1, 0.5%). RC-IPGs were inserted at initial DBS implantation in 123 patients (60%), while 83 patients (40%) were converted to RC-IPGs during an IPG replacement surgery. The authors found that RC-IPG implantation resulted in $60,900 of cost savings over the course of 9 years. Furthermore, patient satisfaction was high with RC-IPG implantation. Overall, 87.3% of patients who responded to the survey were satisfied with their device, and only 6.7% found the rechargeable component difficult to use. In patients who were switched from a standard IPG to RC-IPG, the majority who responded (70.3%) preferred the rechargeable IPG. CONCLUSIONS: RC-IPGs can provide DBS patients with long-term therapeutic benefit while minimizing the need for battery replacement surgery. The authors have implanted rechargeable stimulators in 206 patients undergoing DBS surgery, and here they demonstrate the cost-effectiveness and high patient satisfaction associated with this procedure.

Comparative mechanical analysis of deep brain stimulation electrodes.

The new field of neuro-prosthetics focuses on the design and implementation of neural prostheses to restore some of the lost neural functions. The electrode-tissue contacts remain one of the major obstacles of neural prostheses microstructure. Recently, Microelectrode fabrication techniques have been developed to have a long-term and stable interface with the brain. In this paper, a comparative analysis of finite element models (FEM) for several electrode layouts is conducted. FEM involves parametric and sensitivity analysis to show the effects of the different design parameters on the electrode mechanical performance. These parameters include electrode dimensions, geometry, and materials. The electrodes mechanical performance is evaluated with various analysis techniques including: linear buckling analysis, stationary analysis with axial and shear loading, and failure analysis for brittle and ductile materials. Finally, a novel figure of merit (FOM) is presented and dedicated to the various electrodes prototypes. The proposed designs take into account mechanical performance, fabrication cost, and cross sectional area of the electrode. The FOM provides important design insights to help the electrodes designers to select the best electrode design parameters that meet their design constraints.

Cost-Minimization Analysis of Deep-Brain Stimulation Using National Database of Japanese Health Insurance Claims.

OBJECTIVES: A new rechargeable dual-channel deep brain stimulation (DBS) system has been introduced for the treatment of Parkinson's disease and other movement disorders. However, the clinical value of the device, which has a high cost, remains unclear. MATERIALS AND METHODS: We conducted a cost-minimization analysis using a national database of health insurance claims in Japan. DBS-related costs were compared between rechargeable and non-rechargeable devices and estimated across a 20-year period. RESULTS: Although the price of rechargeable DBS was higher than that of non-rechargeable DBS, we observed total cost-savings of 8.4 million yen across 20 years by considering costs related to implantation surgery, frequency of replacement, and risk of complications. CONCLUSIONS: In this study, real-world evidence indicated that rechargeable dual-channel DBS is a reasonable choice for saving total medical costs. Price revisions should consider cost-effectiveness findings for medical devices.

Post-operative deep brain stimulation assessment: Automatic data integration and report generation.

BACKGROUND: The gold standard for post-operative deep brain stimulation (DBS) parameter tuning is a monopolar review of all stimulation contacts, a strategy being challenged by recent developments of more complex electrode leads. OBJECTIVE: Providing a method to guide clinicians on DBS assessment and parameter tuning by automatically integrating patient individual data. METHODS: We present a fully automatic method for visualization of individual deep brain structures in relation to a DBS lead by combining precise electrode recovery from post-operative imaging with individual estimates of deep brain morphology utilizing a 7T-MRI deep brain atlas. RESULTS: The method was evaluated on 20 STN DBS cases. It demonstrated robust automatic creation of 3D-enabled PDF reports visualizing electrode to brain structure relations and proved valuable in detecting miss placed electrodes. DISCUSSION: Automatic DBS assessment is feasible and can conveniently provide clinicians with relevant information on DBS contact positions in relation to important anatomical structures.

Management of Hardware Related Infections after DBS Surgery: A Cost Analysis.

AIM: To investigate the costs of treating the infection with antibiotics only with the risk of surgery when unsuccessful versus immediate removal followed by re-implantation in patients with deep brain stimulation (DBS) hardware infection. MATERIAL AND METHODS: We calculated the costs of the different strategies through a standard costing procedure. A decision model has been applied to establish the average treatment cost per patient representative for a clinical setting where both strategies are employed. Subsequently, a sensitivity analysis has been performed to assess the influence of clinical assumptions regarding the effectiveness of antibiotics treatment on average treatment costs. RESULTS: The costs of treating a case of DBS hardware infection with immediate internal pulse generator (IPG) replacement surgery were ?29,301 compared to ?9499 for successful antibiotic treatment. For antibiotic treatment followed by IPG replacement surgery the total costs were ?38,741. Antibiotic treatment alone was successful in 44% (4/9) of the included cases of DBS infection, resulting in average treatment costs per patient of ?25,745. Trying to resolve DBS hardware infections initially with antibiotics reduced treatment costs by 12.1%. CONCLUSION: Treatment with antibiotics with the risk of a later removal when unsuccessful was a more valuable strategy in terms of costs when compared to immediate surgical intervention in cases of hardware-related infections in DBS surgeries.

Brain Shift and Pneumocephalus Assessment During Frame-Based Deep Brain Stimulation Implantation With Intraoperative Magnetic Resonance Imaging.

BACKGROUND: Brain shift and pneumocephalus are major concerns regarding deep brain stimulation (DBS). OBJECTIVE: To report the extent of brain shift in deep structures and pneumocephalus in intraoperative magnetic resonance imaging (MRI). METHODS: Twenty patients underwent bilateral DBS implantation in an MRI suite. Volume of pneumocephalus, duration of procedure, and 6 anatomic landmarks (anterior commissure, posterior commissure, right fornix [RF], left fornix [LF], right putaminal point, and left putaminal point) were measured. RESULTS: Pneumocephalus varied from 0 to 32 mL (median = 0.6 mL). Duration of the procedure was on average 195.5 min (118-268 min) and was not correlated with the amount of pneumocephalus. There was a significant posterior displacement of the anterior commissure (mean = -1.1 mm, P < .001), RF (mean = -0.6 mm, P < .001), LF (mean = -0.7 mm, P < .001), right putaminal point (mean = -0.9 mm, P = .001), and left putaminal point (mean = -1.0 mm, P = .001), but not of the posterior commissure (mean = 0.0 mm, P = .85). Both RF (mean = -.7 mm, P < .001) and LF (mean = -0.5 mm, P < .001) were posteriorly displaced after a right-sided burr hole. There was a correlation between anatomic landmarks displacement and pneumocephalus after 2 burr holes (rho = 0.61, P = .007), but not after 1 burr hole (rho = 0.16, P = .60). CONCLUSION: Better understanding of how pneumocephalus displaces subcortical structures can significantly enhance our intraoperative decision making and overall targeting strategy.

Informe de intervenciones no favorables: enfermedad de parkinson / Report of unfavorable interventions: Parkinson's disease

INTRODUCCIÓN: La Enfermedad de Parkinson (EP) es la segunda enfermedad neurodegenerativa más común (después de la enfermedad de Alzheimer) en el sistema nervioso central, afectando principalmente el sistema motor. Actualmente los medicamentos antiparkinsonianos como levodopa y agonistas dopaminérgicos son la primera línea de tratamiento para EP. Estos medicamentos pueden mejorar los síntomas tempranos de EP, pero se vuelven inefectivos e incluso producen efectos adversos, como disquinesia y síntomas psicóticos, a medida que la enfermedad progresa. La terapia de estimulación cerebral profunda (ECP) es un tratamiento quirúrgico que puede reducir algunos de los síntomas asociados a la Enfermedad de Parkinson. Para ésto, se utiliza un dispositivo médico implantado quirúrgicamente, similar a un marcapasos cardíaco, para administrar estimulación eléctrica en áreas muy definidas del cerebro. La estimulación de estas áreas bloquea las señales que causan los síntomas motores incapacitantes de la enfermedad de Parkinson. La estimulación eléctrica puede ajustarse de forma no invasiva para aumentar al máximo los beneficios de la terapia. Como resultado, muchas personas logran tener un mayor control sobre los movimientos de su cuerpo. TECNOLOGÍAS SANITARIA DE INTERÉS: La terapia de estimulación cerebral profunda (ECP): Es un tratamiento quirúrgico que puede reducir algunos de los síntomas asociados a la EP. Para ésto, se utiliza un dispositivo médico implantado quirúrgicamente, similar a un marcapasos cardíaco, para administrar estimulación eléctrica en áreas muy definidas del cerebro. La estimulación de estas áreas bloquea las señales que causan los síntomas motores incapacitantes de la enfermedad de Parkinson. La estimulación eléctrica puede ajustarse de forma no invasiva para aumentar al máximo los beneficios de la terapia. Como resultado, muchas personas logran tener un mayor control sobre los movimientos de su cuerpo. EFICACIA DE LOS TRATAMIENTOS: La ECP está asociada con un mejoramiento significativo en la función motora, calidad de vida y reducción de dosis de L-dopa. Existe una posibilidad pequeña de serios eventos adversos como hemorragia subaracnoidea. Es necesario que la cirugía sea realizada por un equipo multidisciplinario y experimentado para asegurar la selección óptima de personas y reducir el riesgo de eventos adversos. ALTERNATIVAS DISPONIBLES: Tratamiento farmacológico: Destinados principalmente al alivio de síntomas de la enfermedad. Entre los fármacos que se utilizan para el tratamiento de síntomas motores se puede mencionar a levodopa, antagonistas de la dopamina, anticolinérgicos, amantadina e inhibidores de la monoamino oxidasa, entre otros. Por otro lado, se utilizan medicamentos para el tratamiento de síntomas no motores derivados de condiciones relacionadas (comorbilidades o secuelas del tratamiento) como psicosis, demencia, depresión y fatiga. Tratamiento no farmacológico: Entre las intervenciones no farmacológicas para el tratamiento de la enfermedad de Parkinson se encuentran educación, programas de apoyo, terapias de ejercicios y del lenguaje. Cirugía: Estimulador cerebral profundo: consiste en estimular eléctricamente a través de la implantación de electrodos en ciertas zonas del cerebro, con el objetivo de controlar los síntomas del Parkinson. Esta técnica tiene como ventaja que es reversible evitando la destrucción de tejido. Otros procedimientos quirúrgicos: talamotomía, palidotomía, subtalamotomía, entre otros. RESULTADOS DE LA BÚSQUEDA DE EVIDENCIA: La información presentada fue extraída de 3 revisiones sistemáticas publicadas entre los años 2013 y 2016 que evaluaron el dispositivo de estimulación cerebral profunda, en comparación con terapia farmacológica. CONCLUSIÓN: Para dar cumplimiento al artículo 28° del Reglamento que establece el proceso destinado a determinar los diagnósticos y tratamientos de alto costo con Sistema de Protección Financiera, según lo establecido en los artículos 7°y 8° de la ley N°20.850, aprobado por el decreto N°13 del Ministerio de Salud, se concluye que el presente informe de evaluación se considera no favorable, de acuerdo a lo establecido en el Título III. de las Evaluaciones Favorables de la Norma Técnica N° 0192 de este mismo ministerio.

Parkinsonian rest tremor can be detected accurately based on neuronal oscillations recorded from the subthalamic nucleus.

OBJECTIVE: To investigate the possibility of tremor detection based on deep brain activity. METHODS: We re-analyzed recordings of local field potentials (LFPs) from the subthalamic nucleus in 10 PD patients (12 body sides) with spontaneously fluctuating rest tremor. Power in several frequency bands was estimated and used as input to Hidden Markov Models (HMMs) which classified short data segments as either tremor-free rest or rest tremor. HMMs were compared to direct threshold application to individual power features. RESULTS: Applying a threshold directly to band-limited power was insufficient for tremor detection (mean area under the curve [AUC] of receiver operating characteristic: 0.64, STD: 0.19). Multi-feature HMMs, in contrast, allowed for accurate detection (mean AUC: 0.82, STD: 0.15), using four power features obtained from a single contact pair. Within-patient training yielded better accuracy than across-patient training (0.84vs. 0.78, p=0.03), yet tremor could often be detected accurately with either approach. High frequency oscillations (>200Hz) were the best performing individual feature. CONCLUSIONS: LFP-based markers of tremor are robust enough to allow for accurate tremor detection in short data segments, provided that appropriate statistical models are used. SIGNIFICANCE: LFP-based markers of tremor could be useful control signals for closed-loop deep brain stimulation.

Rechargeable or Nonrechargeable Deep Brain Stimulation in Dystonia: A Cost Analysis.

OBJECTIVE: Deep brain stimulation of the internal Globus Pallidus (GPi DBS) delivered by an implantable neurostimulator (INS) is an established, effective, and safe treatment option for patients with medically refractory primary dystonia. Compared to other DBS targets, the battery life of the INS is substantially shorter due to the higher energy demands required to penetrate the GPi resulting in faster battery depletion and more frequent hospitalizations for INS replacement. We, therefore, performed a cost analysis to compare a rechargeable DBS system, Activa®RC, with nonrechargeable systems, from the perspective of the French public health insurer. MATERIALS AND METHODS: To estimate the cost of INS replacement in the nonrechargeable cohort, and costs potentially avoided in the hypothetical Activa® RC cohort, the medical records of patients who had undergone GPi DBS with a nonrechargeable INS between 1996 and 2010 at a center in France were accessed. Replacement rates were estimated for up to nine years. RESULTS: With Activa® RC, a total of 315 hospitalizations for replacement procedures would have been avoided over nine years compared with a nonrechargeable INS, resulting in a discounted mean direct medical cost per patient over nine years of €50,119 with a nonrechargeable INS and €33,306 with Activa® RC, a reduction of 34%. CONCLUSIONS: The adoption of a rechargeable instead of a nonrechargeable INS for eligible patients with dystonia may provide substantial savings to the public health insurer in France.

Informe de evaluación científica en la evidencia disponible: distonía / Scientific evaluation report on the available evidence: dystonia

INTRODUCCIÓN: La distonía es un desorden del movimiento común caracterizado por la contracción muscular sostenida o intermitente que causa movimientos anormales (distónicos), posturas anormales e incluso temblores. Los síntomas frecuentemente comienzan en las extremidades, generalmente en las piernas, para luego avanzar a otras áreas del cuerpo hasta convertirse en un síntoma generalizado en más del 50% de los pacientes. En cambio, cuando el paciente presenta una manifestación tardía, posterior a los 21 años, es más común que empiece por el cuello, brazos o cabeza y tienda a mantenerse de forma focal o segmental. La Estimulación Cerebral Profunda (ECP) actúa eléctricamente en el cerebro mediante un dispositivo, similar a un marcapaso, que genera pulsos eléctricos que son transmitidos a través de electrodos, que son implantados quirúrgicamente en la zona interna del cerebro. Este informe evalúa el uso de este implante para la ECP en pacientes con distonía generalizada severa, que no respondan al tratamiento farmacológico y a las inyecciones de toxina botulínica. TECNOLOGÍAS SANITARIA DE INTERÉS: La estimulación cerebral profunda estimula eléctricamente el cerebro, mediante un dispositivo, similar a un marcapaso, que genera pulsos eléctricos que son transmitidos a través de electrodos, los cuales se implantan quirúrgicamente en la zona interna del "globus pallidus". Este tratamiento no es curativo, del mismo modo que los medicamentos, solo disminuyen los síntomas. EFICACIA DE LOS TRATAMIENTOS: Se encontraron siete revisiones sistemáticas que evaluaban el uso del ECP para pacientes con distonía. En pacientes con distonía primaria severa generalizada con mutación DYT1 de origen desconocido, la evidencia muestra que la ECP en el Globus pallidus internus (GPi) tiene eficacia a largo plazo, pero complicaciones inusuales tardías como la acinesia o la congelación de la marcha. Se observa que un mayor deterioro en la línea de base y una menor edad en la cirugía de ECP estuvieron positivamente relacionados con mejores resultados con GPi-ECP. Todas las revisiones sistemáticas presentan las mismas limitaciones significativas, relacionadas a que la evidencia recopilada son estudios de casos, recopilación de datos multicéntricos, estudios retrospectivos. No hay evidencia disponible sobre estudios clínicos aleatorizados. Entre las desventajas que presenta el ECP se encuentra la necesidad de mantenimiento del dispositivo instalado y la sustitución periódica de la batería. Además, ECP conlleva el riesgo de infección de los materiales implantados, ruptura de los cables de conexión y migración del material. ALTERNATIVAS DISPONIBLES: Tratamiento farmacológico: Muchos agentes orales han sido usados para el tratamiento de la distonía, pero ellos no han sido extensivamente estudiados en ensayos controlados rigurosos. La evidencia disponible sugiere que muchas drogas benefician a una proporción de pacientes con distonía. Inyecciones de toxina botulinum: La toxina botulínica (BoNT) es una potente neurotoxina producida por Clostridium botulinum que causa debilidad muscular regional a través de su acción como una endopeptidasa de zinc que escinde proteínas específicas implicadas en la fusión vesicular. La aplicación de esta toxina reduciría la hiperactividad muscular asociada a esta condición de salud. Cirugía: El tratamiento quirúrgico está reservado para pacientes con distonía grave que no reciben tratamiento con agentes farmacológicos e inyecciones de BoNT. El pilar del tratamiento quirúrgico es la estimulación del microelectrodo profundo del cerebro del segmento interno del globus. RESULTADOS DE LA BÚSQUEDA DE EVIDENCIA: La información presentada fue extraída de 3 revisiones sistemáticas relevantes para la pregunta formulada, las que fueron publicadas entre los años 2006 y 2017, que evaluaron el uso de ECP para pacientes con distonía. En las 3 revisiones sistemáticas utilizadas, se reportaron 2 Ensayos Controlados Aleatorizados (ECAs) que comparaban el uso de ECP contra placebo (sham estimulation) en pacientes con distonía. CONCLUSIÓN: Para dar cumplimiento al artículo 28° del Reglamento que establece el proceso destinado a determinar los diagnósticos y tratamientos de alto costo con Sistema de Protección Financiera, según lo establecido en los artículos 7°y 8° de la ley N°20.850, aprobado por el decreto N°13 del Ministerio de Salud, se concluye que el presente informe de evaluación se considera favorable, de acuerdo a lo establecido en el Título III. de las Evaluaciones Favorables de la Norma Técnica N° 0192 de este mismo ministerio.

[Retinal and Cortical Activation by Electrical Stimulation with Retina Implants]. / Retinale und kortikale Aktivierung durch elektrische Stimulation mit Netzhautimplantaten.

In Germany, about 30,000 to 40,000 people suffer from retinitis pigmentosa (RP), which ultimately results in blindness. The only aid to blind RP patients are retinal implants: These have been under development for several years and have now been approved as a medical product. Retinal implants produce visual perceptions in response to electrical stimulation of the degenerated retina and are useful in the everyday life of blind people. However, the currently achievable quality of vision is such that people with a retinal implant are still legally blind. The visual quality that can be achieved with epi- and subretinal implants depends not only on patient-specific factors such as individual history and status of retinal degeneration, but especially on the interface between implant and retina and the quality of the achievable neuronal activation. Biophysical approaches to functional improvements of the implants are founded on the physiology of the retina (cell density, intraretinal interconnections), are based on technical optimisation of the interface (electrode materials, size and density), and exploit the stimulation protocols with which visual information is fed into the degenerated retina (time courses of electrical stimuli, spatiotemporal stimulation pattern). Optimisation of stimulation parameters can be supported by a detailed analysis of cortical responses, with appropriate electrophysiological and optical methods. This article looks at both the physiological and biophysical fundamentals of electrical retinal stimulation, as well as the resulting retinal and cortical activation.

Versatile 3D-printed headstage implant for group housing of rodents.

BACKGROUND: An unfavourable yet necessary side-effect of stereotaxic surgery involves the social isolation of post-surgery rats, in order to protect their wound site or skull-mounted implant from damage. Social isolation can cause a myriad of behavioural and physiological changes that are detrimental to the well-being of rats, with potential negative implications for a range of experimental paradigms. New method. Female Sprague Dawley rats (n=40) were implanted onto the skull with a novel 3D-printed headstage socket that surrounded an electrode connector. The socket accommodated a removable stainless-steel headcap for the purposes of protecting the implant. Rats were pair-housed following surgery, and their behaviour was monitored for up to several weeks under two experimental conditions that involved EEG recording and deep-brain stimulation, as well as behavioural test sessions inside an open-field maze. Rat weights were compared between individually- and pair-housed rats at up to 3 weeks post-surgery. RESULTS: These experiments were successfully carried out using pair-housed rats, with no damage or complications observed regarding the implant and its headcap. Rats were able to carry out a range of normal behaviours including running, grooming, foraging and sleeping. Compared to individually-housed rats, pair-housed rats gained less weight over the 3 weeks post-implantation period. Comparison with existing method(s). This method offers additional protection compared to group-housed post-surgical rats that lack the protective headcap. It is also potentially more practical and versatile than a fully-implantable device for the safe post-surgery group housing of rodents. CONCLUSIONS: This implant design can reduce the cost of rodent upkeep, whilst potentially avoiding a myriad of behavioural and physiological changes that are known to result from social isolation.

Internal Pulse Generators in Deep Brain Stimulation: Rechargeable or Not?

OBJECTIVE: Deep brain stimulation (DBS) is a cost-effective strategy for the treatment of different neurologic disorders. However, DBS procedures are associated with high costs of implantation and replacement of the internal pulse generator (IPG). Different manufacturers propose the use of rechargeable IPGs. The objective of this study is to compare the implantation costs of nonrechargeable IPGs versus the estimated costs of rechargeable IPGs in different categories of patients to evaluate if an economic advantage for the health care system could be derived. METHODS: The study looked at 149 patients who underwent a surgical procedure for IPG replacement. In a hypothetical scenario, rechargeable IPGs were implanted instead of nonrechargeable IPGs at the time of DBS system implantation. Another scenario was outlined in a perspective period of time, corresponding to the patients' life expectancy. Costs were calculated, and inferential analysis was performed. RESULTS: A savings of €234,194, including the cost of management of complications, was calculated during a follow-up period of 7.9 years. In a comprehensive life expectancy period of 47 years, a savings of €5,918,188 would be obtained (P < 0.05). Long-term group data point out that a relevant savings would be expected from implantation of rechargeable IPGs in dystonic patients (P < 0.05) and patients with Parkinson disease (P < 0.05), and a savings is projected to occur in other categories of patients (P < 0.05). CONCLUSIONS: Implantation of rechargeable IPGs presents clinical advantages compared with nonrechargeable devices. A huge economic savings can be realized with the implantation of rechargeable IPGs in categories of patients implanted with IPGs for DBS.