Computational development of a precise drilling guide for implant insertion in canine vertebral bodies / [Desenvolvimento computacional de um guia cirúrgico de perfuração precisa para inserção de implantes em corpo vertebral de cães]

O tratamento cirúrgico de estabilização da coluna vertebral de cães usualmente requer osteossíntese com uso de implantes, como pinos e parafusos. No entanto, as técnicas atuais de inserção de implantes no corpo vertebral não são totalmente precisas e várias complicações são atribuídas ao ato, como invasão do canal vertebral, danos vasculares e neurológicos. Para promover segurança na inserção de implantes e reduzir a ocorrência de lesões iatrogênicas, vem crescendo o interesse na produção de guias de perfuração em neurocirurgia veterinária. Com o objetivo de assegurar maior precisão e acurácia durante a perfuração óssea, foi desenvolvido um novo design de guia cirúrgico para inserção de implantes em corpo vertebral específico para a anatomia do paciente. A técnica proposta permite determinar o trajeto e o ângulo de perfuração óssea no corredor de implantação de cada vértebra, pela customização da guia e visa reduzir as taxas de complicações, promover precisão no posicionamento de implantes vertebrais e reduzir o tempo cirúrgico.

Clinical Applications of Additive Manufacturing Models in Neurosurgery: a Systematic Review

Introduction Three-dimensional (3D) printing technologies provide a practical and anatomical way to reproduce precise tailored-made models of the patients and of the diseases. Those models can allow surgical planning, besides training and surgical simulation in the treatment of neurosurgical diseases. Objective The aim of the present article is to review the scenario of the development of different types of available 3D printing technologies, the processes involved in the creation of biomodels, and the application of those advances in the neurosurgical field. Methods We searched for papers that addressed the clinical application of 3D printing in neurosurgery on the PubMed, Ebsco, Web of Science, Scopus, and Science Direct databases. All papers related to the use of any additivemanufacturing technique were included in the present study. Results Studies involving 3D printing in neurosurgery are concentrated on threemain areas: (1) creation of anatomical tailored-made models for planning and training; (2) development of devices and materials for the treatment of neurosurgical diseases, and (3) biological implants for tissues engineering. Biomodels are extremely useful in several branches of neurosurgery, and their use in spinal, cerebrovascular, endovascular, neuro-oncological, neuropediatric, and functional surgeries can be highlighted. Conclusions Three-dimensional printing technologies are an exclusive way for direct replication of specific pathologies of the patient. It can identify the anatomical variation and provide a way for rapid construction of training models, allowing the medical resident and the experienced neurosurgeon to practice the surgical steps before the operation.

Historical High Complexity Neurosurgery Development of One of the Poorest Brazilian Regions

Human development rates in the Vale do Jequitinhonha, state of Minas Gerais, Brazil, called "Misery Valley," are among the lowest in the country, not to mention the often precarious psychosocial realities that daily contact with these families reveals. The history of neurosurgery at the Neurosurgical Reference Center at the Vale do Jequitinhonha e Mucuri dates from 2004, when the first neurosurgical procedures were performed in the recently organized Section of Neurosurgery. The historical surgical series shows the positive impact of the service. In 2007, the average was 3 neurosurgeries/month. In the last year, 2018, service growth boosted the record to 34.83 neurosurgeries/month. In addition to performing elective surgery, the neurosurgery team supports the emergency team by performing some neurosurgical procedures. The service number of patients operated since the development of the service is nearly 3,000. Neurosurgery at the Santa Casa de Caridade from Diamantina has been made comparable to the best national neurosurgery services.

Chest tube simulator: development of low-cost model for training of physicians and medical students. / Simulador de dreno de tórax: desenvolvimento de modelo de baixo custo para capacitação de médicos e estudantes de medicina.

OBJECTIVE: by using a 3D printer, to create a low-cost human chest cavity simulator that allows the reproduction of the closed chest drainage technique (CCD), comparing its effectiveness with that of the animal model. METHODS: it was made a 3D printing of the bony framework of a human thorax from a chest computerized tomography scan. After printing the ribs, we performed tests with several materials that contributed to form the simulation of the thoracic cavity and pleura. An experimental, randomized, and controlled study, comparing the efficacy of the simulator to the efficacy of the animal model, was then carried out in the teaching of CCD technique for medical students, who were divided into two groups: animal model group and simulator model group, that trained CCD technique in animals and in the simulator model, respectively. RESULTS: the chest reconstruction required anatomical knowledge for tomography analysis and for faithful 3D surface editing. There was no significant difference in the safety of performing the procedure in both groups (7.61 vs. 7.73; p=0.398). A higher score was observed in the simulator model group for "use as didactic material" and "learning of the chest drainage technique", when compared to the animal model group (p<0.05). CONCLUSION: the final cost for producing the model was lower than that of a commercial simulator, what demonstrates the feasibility of using 3D printing for this purpose. In addition, the developed simulator was shown to be equivalent to the animal model in relation to the simulation of the drainage technique for practical learning, and there was preference for the simulator model as didactic material.

OBJETIVO: criar, em impressora 3D, um simulador de baixo custo de caixa torácica humana que permita a reprodução da técnica de drenagem fechada de tórax (DFT) comparando sua eficácia com a do modelo animal. MÉTODOS: foi realizada impressão 3D do arcabouço ósseo de um tórax humano a partir de uma tomografia de tórax. Após a impressão das costelas, foram realizados testes com diversos materiais que contribuíram para formar a simulação da caixa torácica e da pleura. Foi, então, realizado um estudo experimental, randomizado e controlado comparando sua eficácia ao modelo animal no ensino da DFT para estudantes de medicina, que foram divididos em dois grupos: Grupo Modelo Animal e Grupo Modelo Simulador, que treinaram DFT em animais e no modelo simulador, respectivamente. RESULTADOS: a reconstrução do tórax exigiu o conhecimento anatômico para análise da tomografia e para edição fiel da superfície 3D. Não houve diferença significativa quanto à segurança de realizar o procedimento entre os grupos (7,61 vs. 7,73; p=0,398). Foi observada maior pontuação no grupo modelo simulador para uso como material didático e aprendizado da técnica de drenagem torácica quando comparado ao grupo modelo animal (p<0,05). CONCLUSÃO: o custo final para a confecção do modelo foi inferior ao de um simulador comercial, o que demonstra a viabilidade do uso da impressão 3D para esse fim. Além disso, o simulador desenvolvido se mostrou equivalente ao modelo animal quanto à simulação da técnica de drenagem para aprendizado prático e houve preferência pelo modelo simulador como material didático.

Additive Manufacturing of 3D Biomodels as Adjuvant in Intracranial Aneurysm Clipping.

One of the main difficulties in intracranial aneurysms (IA) surgery refers to the choice of the appropriate clip(s) to be implanted. Although the imaging exams currently available ensure visualization of IA's morphology, they do not bring an accurate reference positioning for the surgeon in executing the surgery procedure nor efficiently contribute to planning the surgery. Unfortunately, for IA's largely inaccessible regions, there is not an efficient method of treatment planning. Therefore, we propose a novel method that allows the generation of a 3D biomodel of the IA region under investigation using additive manufacturing technology (AM). Thus, a physical copy of the IA is produced and offers the surgeon a full view of the anatomy of that region of the brain. The aim of this study is the creation of a flexible 3D physical model (elastomer) through the AM technique, in order to allow the clip selection prior to the surgery. DICOM angio-CT images from eight patients who underwent IA surgery were transformed into STL format and then built on a 3D printer. Preoperative surgical clip selection was performed and then compared with those used in surgery. At the end of the study, all 3D IA biomodels were reproduced for microsurgical clipping selection and it was possible to predict the metal clip to be used in the surgery. In addition, the proposed methodology helps to clarify the surgical anatomy and to avoid excessive manipulation of the intracranial arteries and prolonged surgical time. The major advantage of this technology is that the surgeon can closely study complex cerebrovascular anatomy from any perspective using realistic 3D biomodels, which can be handheld, allowing simulation of intraoperative situations and anticipation of surgical challenges.

Simulador de dreno de tórax: desenvolvimento de modelo de baixo custo para capacitação de médicos e estudantes de medicina / Chest tube simulator: development of low-cost model for training of physicians and medical students

RESUMO Objetivo: criar, em impressora 3D, um simulador de baixo custo de caixa torácica humana que permita a reprodução da técnica de drenagem fechada de tórax (DFT) comparando sua eficácia com a do modelo animal. Métodos: foi realizada impressão 3D do arcabouço ósseo de um tórax humano a partir de uma tomografia de tórax. Após a impressão das costelas, foram realizados testes com diversos materiais que contribuíram para formar a simulação da caixa torácica e da pleura. Foi, então, realizado um estudo experimental, randomizado e controlado comparando sua eficácia ao modelo animal no ensino da DFT para estudantes de medicina, que foram divididos em dois grupos: Grupo Modelo Animal e Grupo Modelo Simulador, que treinaram DFT em animais e no modelo simulador, respectivamente. Resultados: a reconstrução do tórax exigiu o conhecimento anatômico para análise da tomografia e para edição fiel da superfície 3D. Não houve diferença significativa quanto à segurança de realizar o procedimento entre os grupos (7,61 vs. 7,73; p=0,398). Foi observada maior pontuação no grupo modelo simulador para uso como material didático e aprendizado da técnica de drenagem torácica quando comparado ao grupo modelo animal (p<0,05). Conclusão: o custo final para a confecção do modelo foi inferior ao de um simulador comercial, o que demonstra a viabilidade do uso da impressão 3D para esse fim. Além disso, o simulador desenvolvido se mostrou equivalente ao modelo animal quanto à simulação da técnica de drenagem para aprendizado prático e houve preferência pelo modelo simulador como material didático.

ABSTRACT Objective: by using a 3D printer, to create a low-cost human chest cavity simulator that allows the reproduction of the closed chest drainage technique (CCD), comparing its effectiveness with that of the animal model. Methods: it was made a 3D printing of the bony framework of a human thorax from a chest computerized tomography scan. After printing the ribs, we performed tests with several materials that contributed to form the simulation of the thoracic cavity and pleura. An experimental, randomized, and controlled study, comparing the efficacy of the simulator to the efficacy of the animal model, was then carried out in the teaching of CCD technique for medical students, who were divided into two groups: animal model group and simulator model group, that trained CCD technique in animals and in the simulator model, respectively. Results: the chest reconstruction required anatomical knowledge for tomography analysis and for faithful 3D surface editing. There was no significant difference in the safety of performing the procedure in both groups (7.61 vs. 7.73; p=0.398). A higher score was observed in the simulator model group for "use as didactic material" and "learning of the chest drainage technique", when compared to the animal model group (p<0.05). Conclusion: the final cost for producing the model was lower than that of a commercial simulator, what demonstrates the feasibility of using 3D printing for this purpose. In addition, the developed simulator was shown to be equivalent to the animal model in relation to the simulation of the drainage technique for practical learning, and there was preference for the simulator model as didactic material.

Posterior L5-S1 transdiscal screws for high grade spondylolisthesis - a systematic review.

OBJECTIVE: The surgical management of high-grade lumbar spondylolisthesis (HGLS) is complex and aims to achieve both a solid fusion that is able to support the high shear forces of the lumbosacral junction, as well as neural decompression. We performed a systematic literature review of the safety and efficacy of posterior transdiscal (PTD) screw fixation from L5S1 for HGLS and its variations. METHODS: A systematic literature review following the PRISMA guidelines was performed in the PubMed database of the studies describing the use of PTD screw fixation for HGLS. Clinical and radiological data were extracted and discussed. Study quality was assessed with the Oxford Centre for Evidence-Based Medicine Levels of Evidence. RESULTS: Seven studies were included and reviewed; all of them were level IV of evidence. Two of them had large case series comparing different surgical techniques: one concluded that PTD was associated with better clinical outcomes when compared with standard screw fixation techniques and the other suggesting that the clinical and radiological outcomes of PTD were similar to those when an interbody fusion (TLIF) technique was performed, but PTD was technically less challenging. The remaining five studies included small case series and case reports. All of them reported the successful useful of PTD with or without technical variations. CONCLUSIONS: Our review concludes, with limited level of evidence that PTD fixation is a safe and efficient technique for treating HGLS patients. It is technically less demanding than a circumferential fusion, even though proper screw insertion is more demanding than conventional pedicle screw fixation.

Posterior L5-S1 transdiscal screws for high grade spondylolisthesis - a systematic review

SUMMARY OBJECTIVE: The surgical management of high-grade lumbar spondylolisthesis (HGLS) is complex and aims to achieve both a solid fusion that is able to support the high shear forces of the lumbosacral junction, as well as neural decompression. We performed a systematic literature review of the safety and efficacy of posterior transdiscal (PTD) screw fixation from L5S1 for HGLS and its variations. METHODS: A systematic literature review following the PRISMA guidelines was performed in the PubMed database of the studies describing the use of PTD screw fixation for HGLS. Clinical and radiological data were extracted and discussed. Study quality was assessed with the Oxford Centre for Evidence-Based Medicine Levels of Evidence. RESULTS: Seven studies were included and reviewed; all of them were level IV of evidence. Two of them had large case series comparing different surgical techniques: one concluded that PTD was associated with better clinical outcomes when compared with standard screw fixation techniques and the other suggesting that the clinical and radiological outcomes of PTD were similar to those when an interbody fusion (TLIF) technique was performed, but PTD was technically less challenging. The remaining five studies included small case series and case reports. All of them reported the successful useful of PTD with or without technical variations. CONCLUSIONS: Our review concludes, with limited level of evidence that PTD fixation is a safe and efficient technique for treating HGLS patients. It is technically less demanding than a circumferential fusion, even though proper screw insertion is more demanding than conventional pedicle screw fixation.

RESUMO OBJETIVOS: O tratamento cirúrgico das listeses de alto grau da coluna lombar (LAGCL) é complexo, objetivando alcançar uma fusão sólida capaz de suportar o estresse biomecânico da junção lombo-sacra, bem como descompressão do tecido neural. Realizamos revisão sistemática da literatura para avaliar a segurança e a eficácia da fixação transdiscal (FTD) L5S1 em LAGCL e suas variações. MÉTODOS: Realizamos revisão sistemática conforme metodologia Prisma na base de dados PubMed dos estudos que utilizaram FTD no tratamento das LAGCL e suas variações. Dados clínicos e radiológicos foram extraídos dos trabalhos e discutidos. A qualidade dos estudos foi avaliada segundo o Oxford Centre for Evidence-Based Medicine Levels of Evidence. RESULTADOS: Sete estudos foram incluídos e analisados, todos com nível IV de evidência. Dois estudos tinham séries de casos maiores, comparando diferentes técnicas cirúrgicas: um concluiu que a FTD foi associada a melhor prognóstico clínico quando comparada à fixação pedicular tradicional, e o outro sugeriu que os resultados clínicos e radiológicos com a FTD foram semelhantes à fusão intersomática, porém com menor demanda técnica na FTD. Os demais cinco estudos eram pequenas séries ou relatos de casos. Todos reportaram o uso da FTD com sucesso, com e sem variações da técnica. CONCLUSÃO: Concluímos que, embora com evidências limitadas, a FTD é segura e efetiva no tratamento das LAGCL. É tecnicamente mais simples do que a fusão circunferencial (intersomática), porém com maior complexidade que a fixação pedicular convencional.

Method to perform safety stereotactic procedures in children under 2 years of age.

INTRODUCTION: Stereotactic procedures have been used in neurosurgery for many years. In children especially, care should be considered to avoid complication caused by fixation of the frame in a not fully developed skull bone. We present our method to adapt the frame in children under 2 years of age. METHODS: Twelve procedures in patients under 24 months were performed between 2003 and 2015. Micromar frame was used. It was adapted with a small pillow made of gauss attached to the posterior part to hold the head, then four pins were fixed without adjustment. We analyze for each patient age, indication, histopathology, and complications. RESULTS: Eleven patients with a mean age of 13.5 months (range 9 to 22 months) underwent 12 stereotactic procedures. In all cases, biopsy samples were obtained, histopathology was positive in 11/12 cases. No complications occurred. CONCLUSION: Stereotactic frame procedures need special attention in small children where the skull bones are not fully developed. We present a simple method to perform this surgery in patients under 2 years of age.

Encuesta Nacional sobre la utilización de catéter venoso central en pacientes sometidos a neurocirugía electiva en Chile / Use of central venous catheter in patients undergoing elective neurosurgery in Chile: A national survey

OBJECTIVES: To know, through an online survey, the usual clinical practice of Chilean anesthesiologists regarding central venous catheterization in patients undergoing elective neurosurgery. MATERIAL AND METHODS: An email was sent with a link to a questionnaire to anesthesiologists belonging to the Society of Anesthesiology of Chile (SACH). The questionnaire consisted of an anonymous questionnaire, with multiple-choice questions that included data referring to experience as an anesthesiologist, experience in neuroanesthesia, indication of central venous access in elective neurosurgery, access of choice, technique used, and immediate and late complications. RESULTS: A valid response was received to the online survey by 180 anesthesiologists, which represents a response rate of 50%. Only 14.4% of the respondents were classified as specialists in neuroanesthesia. The majority acces corresponded to the Internal Jugular. The main indication was the use of vasoactive drugs in 92.18%. Regarding clinical scenarios, 95.4% of respondents used a central venous route in posterior fossa surgery, while only 9.41% used it in minimally invasive surgery. 69.3% of the respondents indicated that they had presented an immediate complication related to the procedure, with arterial puncture being the most frequent with 72.1%. Protocols for perioperative management only existed in 17.8% of cases. There are no significant differences in the usual clinical practice among specialists in neuroanesthesia and general anesthesiologists in most of the items analyzed. CONCLUSIONS: From the data obtained, we observed that there is no uniform criterion in the indication, access and control of the central venous catheter in the context of elective neurosurgery. The foregoing could be explained by the scarce protocolization of anesthetic management in these surgeries. It is of interest to verify that there are no differences in clinical practice among anesthesiologists specialized in this area and those unusual in neurosurgical procedures.

OBJETIVOS: Conocer por medio de una encuesta online la práctica clínica habitual de los anestesiólogos chilenos respecto a la cateterización venosa central en pacientes sometidos a neurocirugía de carácter electivo. MATERIAL Y MÉTODOS: Se envió un correo electrónico con un enlace a un cuestionario a anestesiólogos pertenecientes a la Sociedad de Anestesiología de Chile (SACH). La encuesta consistía en un cuestionario de carácter anónimo, con preguntas de selección múltiple que incluía datos referidos a la experiencia como anestesiólogo, experiencia en neuroanestesia, indicación de vía venosa central en neurocirugía electiva, acceso de elección, técnica utilizada y complicaciones inmediatas y tardías. RESULTADOS: Se recibió respuesta válida a la encuesta online por parte de 180 anestesiólogos, lo que representa una tasa de respuesta del 50%. Sólo el 14,4% de los encuestados son catalogados como especialistas en neuroanestesia. La vía de acceso de elección corresponde a la Yugular Interna con un 66,8% de las preferencias. La principal indicación señalada para su utilización fue el uso de drogas vasoactivas en un 92,18% de los casos. Respecto a escenarios clínicos el 95,4% de los encuestados utiliza una vía venosa central en cirugía de fosa posterior, mientras que sólo el 9,41% la utiliza en cirugía mínimanente invasiva. El 69,3% de los encuestados indica haber presentado alguna vez una complicación inmediata relacionada al procedimiento, siendo la punción arterial la más frecuente con un 72,1%. Protocolos para el manejo perioperatorio sólo existían en 17,8% de los casos. No existen diferencias significativas en la práctica clínica habitual entre los especialistas en neuroanestesia y anestesiólogos poco habituados en neuroanestesia en la mayoría de los ítems analizados. CONCLUSIONES: A partir de los datos obtenidos por esta encuesta online, observamos que no existe un criterio uniforme en la indicación, vía de acceso y control del catéter venoso central en el contexto de la neurocirugía electiva. Lo anterior, podría explicarse por la escasa protocolización del manejo anestésico en estas cirugías. Es de interés comprobar que no existen grandes diferencias en la práctica clínica entre los anestesiólogos especialistas en esta área y aquellos poco habituales en procedimientos neuroquirúrgicos.

Neurovascular stents in pediatric population.

PURPOSE: The purpose of the study is to analyze the results obtained using stents for the treatment of neurovascular diseases in pediatric patients. METHODS: A retrospective study of 6-year period was undertaken evaluating clinical charts and imaging studies of patients treated with stents because of neurovascular diseases. RESULTS: Nine patients were managed with 10 stents. Seven children were females. The median age was 11 years. There were four cases of broad neck cerebral aneurysms, a pseudoaneurysm of the cervical internal carotid artery, a vertebro-jugular fistula, two patients with internal carotid artery (ICA) stenosis affecting the cervical and supraclinoid segment, and a vertebral artery dissection. The only complication was a silent posterior communicating artery (PCoA) thrombosis in a PCoA aneurysm treated with two stents. Dual antiplatelet therapy was given after the procedure to avoid in stent thrombosis. CONCLUSION: Stents are safe and effective for treatment of neurovascular diseases in children, but studies are needed in order to protocolize the use of antiplatelet drugs in children.

3D Printed Models and Navigation for Skull Base Surgery: Case Report and Virtual Validation.

In recent years, computer-assisted surgery tools have become more versatile. Having access to a 3D printed model expands the possibility for surgeons to practice with the particular anatomy of a patient before surgery and improve their skills. Optical navigation is capable of guiding a surgeon according to a previously defined plan. These methods improve accuracy and safety at the moment of executing the operation. We intend to carry on a validation process for computed-assisted tools. The aim of this project is to propose a comparative validation method to enable physicians to evaluate differences between a virtual planned approach trajectory and a real executed course. Summarily, this project is focused on decoding data in order to obtain numerical values so as to establish the quality of surgical procedures.

Preliminary results of recurrent cubital tunnel syndrome treated with neurolysis and porcine extracellular matrix nerve wrap.

PURPOSE: To evaluate the clinical results of revision neurolysis and wrapping with porcine extracellular matrix (AxoGuard Nerve Protector, AxoGen Inc., Alachua, FL) for cubital tunnel syndrome after one previous surgical decompression. METHODS: Twelve patients with recurrent cubital tunnel syndrome were treated with decompression, porcine extracellular matrix nerve wrap, and minimal medial epicondylectomy (if not previously performed). The average follow-up period was 41 months (range, 24-61 mo). All patients had recurrent symptoms after having previously undergone one surgical decompression. The mean patient age was 45 years (range, 30-58 y). All patients were evaluated subjectively and objectively (pain, satisfaction, static 2-point discrimination, grip strength, and pinch strength). RESULTS: A significant improvement was demonstrated in postoperative pain levels (from 8.5 to 1.7), grip strength (from 41% to 86% of the unaffected side), and pinch strength (from 64% to 83% of the unaffected side). Static 2-point discrimination improved from an average 10.4 mm preoperatively to 7.6 mm postoperatively. Eleven of 12 patients demonstrated 2 mm or more improvement in 2-point discrimination postoperatively. There were no complications related to the use of the porcine extracellular matrix for nerve wrapping. CONCLUSIONS: This study found that secondary decompression combined with porcine extracellular matrix nerve wrapping was an effective and safe treatment for patients with recurrent cubital tunnel syndrome. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The role of an aligned nanofiber conduit in the management of painful neuromas in rat sciatic nerves.

BACKGROUND: Capping techniques have been used as a treatment modality for the prevention of neuroma formation and the management of neuropathic pain. However, the results are inconsistent and unpredictable. We hypothesize that this situation may be attributable, in part, to the disparities in the type of materials used to manufacturing of the conduits. METHODS: In this study, a rat model was used and the sciatic nerve was selected for evaluation. In 1 capping group, a sciatic nerve stump was capped with a nonaligned nanofiber conduit (the nonaligned group), whereas in a second capping group, the conduit was made of aligned nanofibers (the aligned group). In another group, the sciatic nerve stump was not capped as a control (the control group). The results of autotomy behavior, extent of neuroma formation, histological changes in the neuroma, and the expression of c-fos as a pain marker in the fourth lumbar spinal cord were evaluated at 8 weeks postoperatively. RESULTS: The control group presented more neuroma-like features in all the observed parameters in comparison with the 2 capping groups; of the 2 capping groups, the aligned group achieved even better outcomes than the nonaligned group. CONCLUSIONS: Our findings indicate that the aligned nanofiber conduit is a promising biomaterial for the nerve capping technique, and new treatment strategies using aligned nanofiber conduits may be developed for the management of painful amputated neuromas.

Head positioning for anterior circulation aneurysms microsurgery.

OBJECTIVE: To study the ideal patient's head positioning for the anterior circulation aneurysms microsurgery. METHOD: We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patient's head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. RESULTS: We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. CONCLUSION: The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction.

Head positioning for anterior circulation aneurysms microsurgery / Posicionamento da cabeça para microcirurgias de aneurismas da circulação anterior

Objective To study the ideal patient's head positioning for the anterior circulation aneurysms microsurgery. Method We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patient's head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. Results We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. Conclusion The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction. .

Objetivo Estudar o posicionamento da cabeça para a cirurgia de aneurismas cerebrais da circulação anterior. Método Dividimos o estudo em duas partes. Inicialmente, dez cabeças de cadáveres frescos foram posicionadas e dissecadas de modo a expor, de maneira ideal, os principais sítios de aneurismas na circulação anterior do cérebro. Posteriormente, 110 pacientes foram submetidos a microcirurgia para clipagem de aneurismas cerebrais da circulação anterior. Durante as cirurgias, as cabeças foram posicionadas de acordo com a localização específica de cada aneurisma e o resultado obtido no estudo dos cadáveres. Cada paciente teve sua posição avaliada quanto a sua eficácia. Resultados Obtivemos basicamente dois padrões de posicionamento da cabeça para cirurgias de aneurismas cerebrais da circulação anterior. Conclusão A melhor exposição cirúrgica está relacionada à posição específica da cabeça para cada localização aneurismática. O ângulo de visão microscópica adequado minimiza lesões neurovasculares e a excessiva retração cerebral. .

Advances in radiofrequency ablation of the cerebral cortex in primates using the venous system: Improvements for treating epilepsy with catheter ablation technology.

BACKGROUND: Pharmacology frequently fails for the treatment of epilepsy. Although surgical techniques are effective, these procedures are highly invasive. We describe feasibility and efficacy of minimally invasive mapping and ablation for the treatment of epilepsy. METHODS: Mapping and radiofrequency ablations were performed via the venous system in eleven baboons and three dogs. RESULTS: Mapping in deep cerebral areas was obtained in all animals. High-frequency pacing was able to induce seizure activity of local cerebral tissue in 72% of our attempts. Cerebral activity could be seen during mapping. Ablative lesions were deployed at deep brain sites without steam pops or sudden impedance rise. Histologic analysis showed necrosis at the sites of ablation in all primates. CONCLUSION: Navigation through the cerebral venous system to map seizure activity is feasible. Radiofrequency energy can be delivered transvenously or transcortically to successfully ablate cortical tissue in this animal model using this innovative approach.

Efficacy and safety of a porcine collagen sponge for cranial neurosurgery: a prospective case-control study.

OBJECTIVE: The use of dural grafts is very useful when primary dural closure cannot be achieved. Our primary objective was to study the incidence of postoperative cerebrospinal fluid leak, including fistula and pseudomeningocele, and postoperative infection by comparing autologous material and a new collagen graft. MATERIALS AND METHODS: A prospective nonrandomized study with a new collagen-based product derived from porcine cells (Peridry) was performed. It was used for dural replacement in 50 patients who underwent a variety of neurosurgical procedures requiring the use of a dural graft. These results were compared with a control group of 50 patients who were treated with autologous duraplasty material. The follow-up period was 3 months. RESULTS: Postoperative overall cerebrospinal fluid fistula occurred in 6% of both groups. No patient in the collagen group developed any sort of infection. One patient in the control developed osteomyelitis in the bone flap. CONCLUSION: The new collagen-based product derived from porcine cells (Peridry), compared with an autologous tissue, is safe, effective, easy to use, as well as time saving in cranial neurosurgery.