Modulação de excitabilidade por meio da estimulação cerebral de alta e baixa frequência no modelo de Kindling hipocampal

Resumo: Há relatos de que estimulação de baixa e alta frequência (LFS e HFS, respectivamente) modifica as características de crises convulsivas em ratos. Nesta tese se relata os efeitos de LFS e HFS aplicadas em dois ou quarto locais em ratos com o processo de kindling completo. Os ratos foram submetidos a um processo de kindling através de um tetrodo hipocampal até a plena aquisição do mesmo. Animais com limiar de pós-descarga (AD) estável foram randomicamente divididos em cinco grupos. Estimulação a 1 Hz (LFS) ou 130 Hz (HFS) foi continuamente aplicada por sete dias através de dois ou quatro contatos intrahipocampais. Um grupo controle não recebeu estimulação. Estimulação aplicada por meio de quatro contatos foi realizada de maneira rotatória, sendo alternada entre os pares de contatos. Os efeitos da estimulação no limiar de AD, duração da AD e padrão comportamental das crises convulsivas foram avaliados. A LFS de quatro contatos elevou consistentemente o limiar de AD por um período de dois dias a duas semanas, enquanto a HFS de quatro contatos diminuiu significativamente a duração da AD, 24 horas após o término da estimulação. Nenhuma modificação significativa foi observada com os paradigmas de estimulação de dois contatos. Nenhuma modificação relevante no padrão comportamental das crises convulsivas foi observado. Estes achados sugerem que o efeito da estimulação hipocampal depende da topografia e da frequência da estimulação. LFS e HFS apresentaram efeitos antiepilépticos na pós-descarga quando aplicadas de forma rotatória. Isto suporta a aplicação dos conceitos de estimulação composta a fim de se induzir dessincronização e efeitos anti-kindling no sistema neura

A utilização de sistemas computacionais no desenvolvimento e análise do modelo animal de Kindling Hipocampal/

AnexosOrientador: João Cândido AraújoCo-orientador: Andreas Schulze BonhageDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Clínica Cirúrgica. Defesa: Curitiba, 18 de dezembro de 2007.Inclui bibliografiaÁrea de concentração: Informática no Ensino e na Pesquisa em Cirurgi

Metástases cerebrais de câncer de colo de útero: relato de três casos

Cervical uterine cancer (CUC) spreads locally (pelvis and paraortic lymphnodes) or distantly (lungs, liver and bones). Metastasis to central nervous system (CNS) are rare. There are about 80 cases reported in the literature. Outcome is poor and survival varies from 3 to 6 months. Three cases of CNS metastasis from CUC are reported, one infratentorial and two supratentorials in location. In one patient, the initial manifestation was due to the cerebral lesion, a feature re p o rted for the first time. All cases were treated by surg e ry, radiotherapy and/or chemotherapy. Clinical findings and treatment options of these rare lesions are reviewed._________________________________________________________________________________________ RESUMO: Tumores do cólo uterino se disseminam por contigüidade ou via hematogênica (pulmão, fígado e ossos). Metástases para sistema nervoso central são incomuns. Apenas cerca de 80 casos são citados na literatura. Manifestações clínicas são devidas à hipertensão intracraniana e a déficits focais. A sobrevida varia de 3 a 6 meses. Três casos são relatados sendo um infratentorial e dois supratentoriais. No primeiro , o diagnóstico da metástase antecedeu o da lesão uterina. No segundo, houve 5 anos sem recidiva após a cirurgia, fato este inédito. O tratamento foi cirurgia, radioterapia e/ou quimioterapia. A discussão enfatiza manejo multidisciplinar destas raras lesões

Continuous High-Frequency Stimulation of the Subthalamic Nucleus Improves Cell Survival and Functional Recovery Following Dopaminergic Cell Transplantation in Rodents

Subthalamic nucleus (STN) high-frequency stimulation (HFS) is a routine treatment in Parkinson’s disease (PD), with confirmed long-term benefits. An alternative, but still experimental, treatment is cell replacement and restorative therapy based on transplanted dopaminergic neurons. The current experiment evaluated the potential synergy between neuromodulation and grafting by studying the effect of continuous STN-HFS on the survival, integration, and functional efficacy of ventral mesencephalic dopaminergic precursors transplanted into a unilateral 6-hydroxydopamine medial forebrain bundle lesioned rodent PD model. One group received continuous HFS of the ipsilateral STN starting a week prior to intrastriatal dopaminergic neuron transplantation, whereas the sham-stimulated group did not receive STN-HFS but only dopaminergic grafts. A control group was neither lesioned nor transplanted. Over the following 7 weeks, the animals were probed on a series of behavioral tasks to evaluate possible graft and/or stimulation-induced functional effects. Behavioral and histological data suggest that STN-HFS significantly increased graft cell survival, graft–host integration, and functional recovery. These findings might open an unexplored road toward combining neuromodulative and neuroregenerative strategies to treat severe neurologic conditions

Modulação de excitabilidade por meio da estimulação cerebral de alta e baixa frequência no modelo de Kindling hipocampal

Resumo: Há relatos de que estimulação de baixa e alta frequência (LFS e HFS, respectivamente) modifica as características de crises convulsivas em ratos. Nesta tese se relata os efeitos de LFS e HFS aplicadas em dois ou quarto locais em ratos com o processo de kindling completo. Os ratos foram submetidos a um processo de kindling através de um tetrodo hipocampal até a plena aquisição do mesmo. Animais com limiar de pós-descarga (AD) estável foram randomicamente divididos em cinco grupos. Estimulação a 1 Hz (LFS) ou 130 Hz (HFS) foi continuamente aplicada por sete dias através de dois ou quatro contatos intrahipocampais. Um grupo controle não recebeu estimulação. Estimulação aplicada por meio de quatro contatos foi realizada de maneira rotatória, sendo alternada entre os pares de contatos. Os efeitos da estimulação no limiar de AD, duração da AD e padrão comportamental das crises convulsivas foram avaliados. A LFS de quatro contatos elevou consistentemente o limiar de AD por um período de dois dias a duas semanas, enquanto a HFS de quatro contatos diminuiu significativamente a duração da AD, 24 horas após o término da estimulação. Nenhuma modificação significativa foi observada com os paradigmas de estimulação de dois contatos. Nenhuma modificação relevante no padrão comportamental das crises convulsivas foi observado. Estes achados sugerem que o efeito da estimulação hipocampal depende da topografia e da frequência da estimulação. LFS e HFS apresentaram efeitos antiepilépticos na pós-descarga quando aplicadas de forma rotatória. Isto suporta a aplicação dos conceitos de estimulação composta a fim de se induzir dessincronização e efeitos anti-kindling no sistema neura

Deep Brain Stimulation for Parkinson’s Disease: Clinical Efficacy and Future Directions for Enhancing Motor Function

Deep Brain Stimulation (DBS) is a well-established procedure that produces a significant improvement in motor symptoms in patients with advanced Parkinson’s disease (PD). While the motor function improvement has been documented extensively, the effects of DBS on non-motor symptoms, such as sleep, cognition, and mood, have been less studied. This review will summarize the extensive clinical evidence on the effects of DBS in PD, and emerging evidence on non-motor symptoms as well as the advances in technology that allows a more precise lead placement and better outcomes. Future directions in the field of neuromodulation and strategies to improve overall brain function will be reviewed. The recent advances in technology provide the ability to deliver stimulation adaptively based on cortical and subcortical brain signals, and subsequently a more physiological and precise modulation of the impaired motor network

Review of spinal cord stimulation for disorders of consciousness

Purpose of review High-cervical spinal cord stimulation can alter cortical activity and cerebral metabolism. These effects are potentially beneficial for disorders of consciousness. A better understanding of the effects of clinical application of stimulation is needed. We aimed to evaluate the existing literature to determine the state of available knowledge. We performed a literature review of clinical studies assessing cervical spinal cord epidural stimulation for disorders of consciousness. Only peer-reviewed articles reporting preoperative and postoperative clinical status were included. Recent findings Nineteen studies were included. A total of 532 cases were reported, and 255 patients were considered responsive (47.9%). Considering only studies published after the definition of minimally conscious state (MCS) as an entity, 402 individuals in unresponsive wakefulness syndrome (UWS) and 113 in MCS were reported. Responsiveness to SCS was reported in 170 UWS patients (42.3%) and in 78 MCS cases (69.0%), although the criteria for responsiveness and outcome measures varied among publications. Summary Cervical SCS yielded encouraging results in patients with disorders of consciousness and seems to be more effective in MCS. More extensive investigation is needed to understand its potential role in clinical practice

Introduction and History of Neuromodulation for Pain

Neuromodulation techniques for pain treatment have been used since ancient Rome, but knowledge about the interaction of electricity and drugs with the central nervous system (electrical and chemical neuromodulation) was not clear until the middle of the twentieth century. It was only then that the advent of neuromodulatory techniques allowed for more widespread clinical application for the treatment of several neurological and psychiatric conditions, including pain. In this chapter, we present the history of neuromodulation techniques for the treatment of pain, from its first applications to a more organized approach encompassing physiological and technological improvements producing the current concepts in neuromodulation. We also take an in-depth look at the current surgical techniques for neuromodulatory improvement of pain

Retrograde thoracic spinal cord stimulation paddle placement for complex persistent spinal pain syndrome type 2

BACKGROUNDSpinal cord stimulation (SCS) is a cost-effective option for treating refractory persistent spinal pain syndrome type-2 (PSPS-2). For patients with extensive spine instrumentation including the thoraco-lumbar junction, percutaneous placement of SCS leads is usually not an option being paddle leads typically implanted anterograde. Paddle lead placement will be particularly challenging in more complex cases when the instrumentation covers the targeted level. To overcome this barrier, we studied using a retrograde approach to reach the sweet spot, facilitate the placement, and reduce associated risks.OBJECTIVESTo study the use of retrograde SCS paddle as a placement method to optimize the spinal cord target and reduce the risks of conventional placement in complex cases.STUDY DESIGNCase series and technical note.METHODSWe present three cases of thoracic retrograde SCS paddle lead placement cases, detailing patient selection, operative technique, and outcome. All the cases had extensive instrumentation to the thoraco-lumbar spine, and one had additional spinal canal stenosis. The surgical procedure entailed a retrograde midthoracic inter-laminar approach, flavectomy, and caudal placement of the paddle lead with intraoperative neurophysiologic monitoring (IONM) guidance for functional midline determination.RESULTSAll the cases had a successful lead placement over the sweet spot without complications. The same approach was used to decompress a focal spinal stenosis in one case. One case had significantly improved pain and hence underwent a pulse generator implant. The other cases had non-satisfactory pain control and were explanted.LIMITATIONSThese case description could guide technical procedural steps, however, a larger number of such cases would be needed to describe further technical nuances.CONCLUSIONSWe demonstrated that placing SCS paddle leads via retrograde midthoracic approach with IONM guidance is safe. This procedure should be an option for SCS paddle implants in patients with posterior spinal fusion encompassing the intended targeted spinal stimulation level