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.

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.

Bilan de 24 mois d'activités neurochirurgicales au centre hospitalier régional Lomé commune (Togo)

Objectif: Présenter et discuter les résultats de l'activité neurochirurgicale au Centre Hospitalier Régional Lomé Commune.Patients et Méthode:Nous avons mené une étude rétrospective de Juillet 2014 à Juillet 2016, incluant les patients opérés pour une affection neurochirurgicale. Les paramètres étudiés étaient épidémio- logiques, diagnostiques, chirurgicaux et évolutifs. Résultats:Cent quatre-vingt-douze patients ont été opérés. Leur âge moyen était de 42,14 ans [0-72]. Le sex ratio étaitde 1,94 en faveur des hommes. La durée moyenne du séjour hospitalier en post opératoire était de 8,2 jours. Les affections dégénératives du rachis ont été la première pathologie concernée par la chirurgie (49,48%), suivies des traumatismes du rachis (17,19%). L'évolution a été favorable dans 90,1% des cas, pour l'ensemble de la série. Nous avons noté 1,6% de cas d'infection du site opératoire, sur l'ensemble de la série. Conclusion : Les résultats sont encourageants pour l'ensemble de la série. L'essor de la pratique neurochirurgicale au Togo nécessite la création d'unités neurochirurgicales indépendantes, une amélioration du plateau technique et une coopération multidisciplinaire

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.

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.

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. .

Suction tube with pressure regulation: technical note / Aspirador com pressão de sucção regulável: nota técnica

We describe a new suction tube for microsurgical procedures which permit a precise control of the pressure of suction. The new device consists of a suction tube connected to a laterally placed sliding bar which progressively opens or closes a leak. The surgeon can readily adjust the suction pressure by moving slightly the sliding bar with his thumb or index finger up and down almost instantaneously.

Descrevemos um novo aspirador para procedimentos microcirúrgicos que permite controle preciso da pressão de sucção. Consiste de tubo de aspiração conectado lateralmente com barra deslizante que abre ou fecha progressivamente uma fenda. O cirurgião pode ajustar rapidamente a pressão de sucção por meio de movimentação delicada da barra deslizante com o dedo indicador ou polegar.

The clip-wrap technique in the treatment of intracranial unclippable aneurysms / Técnica de "clip-wrap" no tratamento de aneurismas rotos não clipáveis

Fusiform and dolichoectatic aneurysms are challenging lesions to treat with direct clipping. Treatment of these aneurysms often requires alternative surgical strategies, including extracranial-intracranial bypass, wrapping, or clip-wrap techniques. Nonetheless, these alternatives methods of treatment have been underused and frequently overlooked. Objective: To report a series of nine cases of otherwise untreatable aneurysms managed using the clip-wrap technique and discuss its surgical nuances. Method: In the last four years, 9 cases of ruptured aneurysms treated by the clip-wrap techniques were identified in the Division of Neurological Surgery, University of São Paulo, School of Medicine. Results: The aneurysms were located at middle cerebral artery (2), anterior choroidal artery (1), anterior communicating artery (1), carotid ophthalmic (3), posterior cerebral artery (1) and posterior-inferior cerebellar artery (1). Three were dolichoectatic, 4 were unsuitable to complete surgical clipping because parent or efferent vessels arises from the aneurysm sac (1 MCA, 1 AcomA, 1 CO, 1 PICA aneurysms) and two, although ruptured aneurysms, were too small (<2mm) to be directly clipped. No early or late rebleeding was observed after 2 years mean follow-up. One patient deceased due to pulmonary tromboembolism. Conclusion: Clip-wrap techniques for the treatment of fusiform and otherwise unclippable aneurysms seem to be safe and it can be associated with a low rate of acute or delayed postoperative complications. It can prevent rebleeding and represents an improvement when compared with the natural history.

Aneurismas fusiformes são lesões de difícil tratamento e frequentemente necessitam de técnicas alternativas de tratamento, incluindo anastomose extra-intracranial ou técnicas de "clip-wrap". Contudo o uso destas técnicas é frequentemente esquecido e negligenciado. Objetivo: Descrever retrospectivamente casuística de nove casos de aneurismas não clipáveis tratados com a técnicas de "clip-wrap" e discutir as nuances cirúrgicas. Resultados: Revisão dos últimos quatro anos da casuística da Divisão de Clínica Neurocirúrgica do HCFMUSP mostrou que 384 casos eram de aneurismas rotos. Destes, 9 eram de aneurismas não clipáveis tratados com a técnica de "clip-wrap". Destes, 2 aneurismas eram de artéria cerebral media, 1 de artéria coroidéia anterior, 1 de artéria comunicante anterior, 3 de artéria oftálmica, 1 de artéria cerebral posterior e 1 de PICA. Três eram lesões ectásicas, 4 não puderam ser completamente clipados devido a relação de aneurismas com vasos eferentes, aferentes ou perfurantes, e dois, apesar de rotos eram pequenos demais para serem clipados (<2,0 mm). Sangramento precoce ou tardio não foram observados, em um seguimento médio de 2 anos. Conclusão: A técnica descrita é segura e está associada com baixa incidência de complicações agudas ou tardias. Ela previne ressangramanto e representa um avanço em relação à história natural destas lesões.

Uma nova pinça regulável para a produção de lesões por esmagamento do nervo ciático do rato / A new adjustable pinch designed for producing crush nerve injuries in the sciatic nerve of rats

OBJETIVO: Foi nosso objetivo, desenvolver uma pinça regulável que permite produzir uma lesão com carga conhecida, num segmento de 5 mm de comprimento do nervo isquiático de ratos. MÉTODOS: O material escolhido para confecção da pinça foi o aço inoxidável, pela sua maior durabilidade e possibilidade de esterilização com soluções anti-sépticas, quase sempre corrosivas. A carga de esmagamento da pinça é regulável, pelo aumento ou diminuição da tensão da mola que a aciona, por meio de um parafuso de regulagem de calibração, feita com uma célula de carga. RESULTADO: A pinça foi utilizada em investigações experimentais e mostrou-se tão eficiente quanto as máquinas de ensaio e de peso morto anteriormente utilizadas. CONCLUSÃO: A pinça desenvolvida apresenta vantagens de ser portátil, de fácil manuseio, baixo custo e permite padronização da carga aplicada.

OBJECTIVE: A new adjustable pinch has been developed for producing a crush injury, with a previously known load of 5 kg, on a 5 mm-long segment of the nerve. METHODS: Stainless steel was the material selected for building the pinch due its durability and possibility of sterilization with anti-septic substances, which are often corrosive. The crushing load of the pinch is adjustable by increasing or decreasing the tension of the spring by means of a screw used for calibration, which is performed by a load cell. RESULT: This pinch has been used in a few experimental investigations and was shown to be as efficient as both the universal testing machine and the dead weight machine, previously used. CONCLUSION: The developed pinch has the advantages of being portable and user-friendly. In addition, the pinch is cheap and allows for the standardization of the applied load.

Radiofrequency Neurotomy of Cervical Medial Branches for Chronic Cervicobrachialgia

Chronic neck and arm pain or cervicobrachialgia commonly occurs with the degeneration of cervical spine. Authors investigated the usefulness of radiofrequency (RF) neurotomies of cervical medial branches in patients with cervicobrachialgia and analyzed the factors which can influence the treatment outcome. Demographic data, types of pain distribution, responses of double controlled blocks, electrical stimulation parameters, numbers and levels of neurotomies, and surgical outcomes were evaluated after mean follow-up of 12 months. Pain distribution pattern was not significantly correlated with the results of diagnostic blocks. Average stimulation intensity was 0.45 V, ranging from 0.3 to 0.69, to elicit pain response in cervical medial branches. The most common involvement of nerve branches was C4 (89%), followed by C5 (82%), C6 (75%), and C7 (43%). Among total of 28 patients, nineteen (68%) reported successful outcome according to outcome criteria after 6 months of followup (p=0.001), and eight (42%) of 19 patients reported complete relief (100%) of pain. Four patients showed recurrence of pain between 6 and 12 months. It was therefore concluded that cervical medial branch neurotomy is considered useful therapeutic modality for the management of cervicobrachialgia in selected patients, particularly in degenerative zygapophyseal disorders.

Extirpación de una lesión del cráneo radioguiada por cintigrafía y detección intraoperatoria / Localization and extirpation of a skull lesion aided by intraoperative radioguidance

La localización de una lesión de la calota craneana puede ser difícil en especial cuando es pequeña y poco evidente a nivel de la superficie externa del cráneo. En este artículo se describe la localización y extirpación guiada por cintigrafía intraoperatoria, de una lesión de 2 cm que comprometía la cara interna del hueso temporal. La expresión radiológica de la lesión en la radiología simple y en la tomografía computada era pobre. Esto hizo difícil la radiología intraoperatoria y la neuronavegación guiada por tomografía computada. En el presente caso se logró extirpar la lesión en bloque. La biopsia fue informada como "Enfermedad de Paget". No hubo complicaciones quirúrgicas.

Double-hook retractor for microlumbar discectomy and foraminotomy.

Aiming to achieve better results in microlumbar discectomy and foraminotomy, a double-hook retractor has been designed to retract lumbar paraspinal muscles away from the spinous process. A double-hook retractor obviates the limitations of single-hook systems.

Acceso endoscopico a la silla turca / Endoscopic access to the turkish chair

El uso endoscopico en el manejo de lesiones selares se ha dinfundido en la ultima década, luego de la experiencia ganada en el tratamiento de lesiones de senos paranasales, el acceso a la logia selar parece ser una progresión lógica. Las ventajas de la técnica endoscopica en relación al microscopio quirúrgico han sido discutidas en la literatura. La familiaridad de esta técnica para los neurocirujanos debe obtenerse potenciando el trabajo en equipo con otorrinolaringólogos y realizando una curva de aprendizaje que incluye el trabajo en cadáver. Se presenta la experiencia inicial con 5 casos de tumores selares tratados con acceso transesfenoidal endoscopico, se revisa la literatura pertinente y se discuten las ventajas y desventajas de la técnica

Manejo neuroquirúrgico de los aneurismas paraclinoídeos / Neurosurgical management of paraclinoid aneurysms

Presentamos el manejo quirúrgico de los aneurismas paraclinoídeos. Discutimos los fundamentos microanatómicos, indicaciones, técnica quirúrgica empleada, complicaciones y resultados de una serie prospectiva de 10 pacientes operados por el equipo vascular del INC Asenjo entre noviembre de 1999 y julio de 2000. Las complicaciones correspondieron a una infección de herida operatoria y una colección extradural en la primera paciente de la serie, un hematoma cervical en otra enferma y un infarto de la arteria coroídea anterior en una paciente con aneurisma global de carótida. Se realizó control neurooftalmológico preoperatorio en todos los pacientes, registrandose en 3 compromisos de nervio óptico postquirúrgicos. No hubo mortalidad en la serie. Especial énfasis se aplica a la importancia del conocimiento microanatómico, al trabajo en equipo y a la planificación prequirúrgica para el manejo de esta compleja patología