Extending the Indications of 5-Aminolevulinic Acid for Fluorescence-Guided Surgery for Different Central Nervous System Tumors: A Series of 255 Cases in Latin America

Introduction Fluorescence guidance with 5-aminolevulinic acid (5-ALA) is a safe and reliable tool in total gross resection of intracranial tumors, especially malignant gliomas and cases of metastasis. In the present retrospective study, we have analyzed 5-ALA-induced fluorescence findings in different central nervous system (CNS) lesions to expand the indications of its use in differential diagnoses. Objectives To describe the indications and results of 5-ALA fluorescence in a series of 255 cases. Methods In 255 consecutive cases, we recorded age, gender, intraoperative 5-ALA fluorescence tumor response, and 5-ALA postresection status, as well the complications related to the method. Postresection was classified as '5-ALA free' or '5-ALA residual'. The diagnosis of histopathological tumor was established according to the current classification of the World Health Organization (WHO). Results There were 195 (76.4%) 5-ALA positive cases, 124 (63.5%) of whom underwent the '5-ALA free' resection. The findings in the positive cases were: 135 gliomas of all grades; 19 meningiomas; 4 hemangioblastomas; 1 solitary fibrous tumor; 27 metastases; 2 diffuse large B cell lymphomas; 2 cases of radionecrosis; 1 inflammatory disease; 2 cases of gliosis; 1 cysticercosis; and 1 immunoglobulin G4-related disease.

Utility of Intraoperative Ultrasound in Neurosurgery

Objective The purpose of the present study is to demonstrate the usefulness of intraoperative ultrasound guidance as a technique for the assessment, in real time, of tumor resection and as a navigation aid during intra-axial brain lesion removal on patients admitted in the Neurosurgical Department at the Hospital Universitario de Caracas, Caracas, Venezuela, in 2018. Methods A total of 10 patients were enrolled, each with intra-axial brain lesions with no previous neurosurgical procedures and a mean age of 49 years old, ranging from 29 to 59 years old. Results A male predominance was observed with 7 cases (70%) over 3 female cases (30%). Six patients had lesions in the dominant hemisphere. The frontal lobe was the most commonly affected,with 5 cases, followed by the parietal lobe,with 4 cases. After craniotomy, ultrasound evaluation was performed previously to dural opening, during tumor resection and after tumor removal. The mean tumor size in axial, coronal and sagittal views was 3.72 cm, 3.08 cm and 3.00 cm, respectively, previously to dural opening with intraoperative ultrasound. The average tumor depth was 1.73 cm from the cerebral cortex. The location and removal duration from the beginning of the approach (ultrasound usage time) was 83.60 minutes, and the average surgery duration was 201 minutes. Navigation with intraoperative ultrasound served to resect intra-axial tumors more precisely and safely. There was no postoperative complication associated with the surgery in this series of cases. Conclusions Intraoperative ultrasound guidance for intra-axial subcortical tumor resection is a technique that serves as a surgical and anatomical orientation tool.

A Simple Method to Avoid Brain Shift during Neuronavigation: Technical Note

Introduction The precise identification of anatomical structures and lesions in the brain is the main objective of neuronavigation systems. Brain shift, displacement of the brain after opening the cisterns and draining cerebrospinal fluid, is one of the limitations of such systems. Objective To describe a simple method to avoid brain shift in craniotomies for subcortical lesions. Method We used the surgical technique hereby described in five patients with subcortical neoplasms. We performed the neuronavigation-guided craniotomies with the conventional technique. After opening the dura and exposing the cortical surface, we placed two or three arachnoid anchoring sutures to the dura mater, close to the edges of the exposed cortical surface. We placed these anchoring sutures under microscopy, using a 6­0 mononylon wire. With this technique, the cortex surface was kept close to the dura mater, minimizing its displacement during the approach to the subcortical lesion. In these five cases we operated, the cortical surface remained close to the dura, anchored by the arachnoid sutures. All the lesions were located with a good correlation between the handpiece tip inserted in the desired brain area and the display on the navigation system. Conclusion Arachnoid anchoring sutures to the duramater on the edges of the cortex area exposed by craniotomy constitute a simple method to minimize brain displacement (brain-shift) in craniotomies for subcortical injuries, optimizing the use of the neuronavigation system.

Abordaje interhemisférico contralateral. Nota técnica / Contralateral interhemispheric approach. Technical note

El abordaje interhemisférico contralateral es una variante del abordaje interhemisférico transcalloso que permite optimizar el acceso a lesiones ubicadas en los ventrículos laterales o en sus paredes. La planificación del ángulo de entrada mediante neuronavegador nos permitió el manejo de un Cavernoma ubicado sobre el núcleo caudado e inmediato a la cápsula interna sin realizar callosotomía convencional ni comprometer las estructuras sensibles adyacentes.

Contralateral interhemispheric approach is a variant of the well-know interhemispheric transcallosal approach that allows to optimize the lateral wall ventricle lesions management. Neuronavigation planning allowed us to deal with a caudate nucleus cavernoma contiguous to internal capsule without conventional callosotomy and additional damage neither.

Cavernoma Paraventricular / Paraventricular Cavernoma

Introducción: Los cavernomas representan el 5 al 13% de las malformaciones cerebrales y suelen tener una localización supratentorial. Clínicamente pueden permanecer asintomáticos o presentar síntomas neurológicos progresivos. Para estos últimos, así como los que presentan hemorragia recurrente, la resección quirúrgica es el tratamiento de elección. Sin embargo, para aquellos que presentan una localización profunda es menester estudiar la relación que existe entre la lesión y las estructuras cerebrales adyacentes. La tractografía (DTI) y las técnicas de navegación intraoperatoria son herramientas fundamentales para planificar y guiar el abordaje a la lesión y realizar un mapeo de las vías de proyección, asociación y comisurales, permitiendo un acceso seguro mediante corticotomías pequeñas y mínima retracción del parénquima cerebral. Objetivo: Describir la técnica quirúrgica guiada por neuronavegación para la resección de un cavernoma frontal derecho profundo yuxtaventricular a través de una pequeña corticotomía. Caso: Paciente de sexo masculino de 20 años de edad, deportista profesional, con parestesias miembro superior izquierdo y cefalea severa. Resonancia magnética evidencia lesión heterogénea en T1 y T2 y presencia de un halo de hemosiderina, compatible con cavernoma a nivel del techo del cuerpo en el ventrículo lateral derecho. Mide 28 mm x 31 mm x 28 mm en sus diámetros transversal, dorso-ventral y rostro-caudal. Tractografía evidencia lesión en íntima relación con el tracto corticoespinal en su recorrido por la corona radiada. Resultados: Exéresis completa de la lesión. El paciente evolucionó sin déficit neurológico y fue dado de alta a las 72 horas del postoperatorio. Conclusión: El uso de la tractografía y de la navegación intraoperatorio, permite abordar lesiones profundas, en contacto con áreas elocuentes, mediante corticotomías pequeñas con mínima retracción cerebral

Introduction: Cavernous malformation represents among 5 to 13% of brain vascular malformations, most of them have a supratentorial location. Clinically they can remain asymptomatic or present with neurological symptoms. In cavernomas with recurrent hemorrhage, located in safe areas, surgical resection is the treatment of choice. However, for those which have a deep yuxta-ventricular localization it is necessary to know the relationship between the lesion and eloquent cerebral structures. Fiber tractography and intraoperative navigation systems are essentials tools to plan and guide the surgical approach and make a mapping of the projection, association and commissural fibers in order to have a safe access to the lesion. Objective: To describe the surgical technique using neuronavigation for the resection of a right frontal yuxta-ventricular cavernous malformation through a minimal approach. Case: A 20-year-old man, professional athlete with left arm paresthesia and severe headache. Magnetic resonance shows a heterogeneous lesion in T1 and T2 with a hemosiderin in the roof of the right lateral ventricle, compatible with a cavernous malformation. Its size was 28 mm x 31mm x 28 mm in the transversal, dorsoventral and rostrocaudal diameter. The fiber tractography shows an intimate relationship with the corticospinal tract on its path through the corona radiata. Results: Complete resection of the lesion. The patient evolved without a neurological deficit and was discharged 72 hours later. Conclusion: The fiber tractography and the intraoperative navigation system allow the deep lesions approach, especially for those who have an intimal relationship with eloquent ́s areas, using minimally corticotomy with less parenchymal retraction.

Resección Tubular Microquirúrgica de un Subependimoma Extenso del Ventrículo Lateral Izquierdo: Video Operatorio en 2D / Microsurgical Tubular Resection of an Extensive Subependymoma of the Left Lateral Ventricle: Operative Video in 2D

Introducción: Los subependimomas intracraneales son raros, representan el 0.2-0.7% de todos los tumores del sistema nervioso central1,2 y se originan en los ventrículos laterales en el 30-40% de los casos.3 Los síntomas usualmente se asocian a hipertensión endocraneana secundaria a hidrocefalia obstructiva.4 La resección completa del tumor es curativa en esta patología.5 El abordaje trans-surcal es seguro para lesiones ventriculares profundas y el uso de los retractores tubulares minimizan la retracción del parénquima cerebral evitando la compresión directa con valvas. Esto permite disminuir la presión del tejido cerebral que puede ocluir los vasos y producir isquemia local generando una lesión neurológica permanente. Descripción del caso: Se presenta el caso de una paciente de 66 años, diestra, con cefalea crónica que aumenta en frecuencia en el último mes. La resonancia cerebral contrastada muestra un tumor extenso en el ventrículo lateral izquierdo con signos de hidrocefalia obstructiva. Intervención: Se coloca la paciente en posición supina. Se hace una incisión bicoronal y se hace un abordaje trans-surcal F1/F2 izquierdo. Se coloca un retractor tubular guiado con el puntero de neuronavegación, introduciéndolo directamente en el parénquima cerebral y fijándolo al soporte de Leyla. Se colocó un catéter de ventriculostomía contralateral y se retira a las 48 horas sin complicaciones asociadas. La resonancia contrastada postoperatoria demuestra una resección completa del tumor. El análisis de patología reveló un subependimoma grado I de la clasificación de la Organización Mundial de la Salud. La paciente presentó transitoriamente apatía y pérdida del control del esfínter urinario que resolvieron completamente a las 3 semanas después de la cirugía. Se firmó un consentimiento firmado para la publicación de la información utilizada en este trabajo. Conclusión: La resección completa microscópica de un subependimoma extenso del ventrículo lateral izquierdo es factible a través de un abordaje tubular transulcal.

Introduction: Intracranial subependymomas are rare, representing only 0.2-0.7% of all central nervous system tumors1,2 and arise in the lateral ventricles in 30-40% of the cases.3 Symptoms depend on tumor location and usually arise when the cerebrospinal fluid (CSF) is blocked, generating a consequent intracranial hypertension.4 Microsurgical gross-total resection is possible and curative for these tumors.5 The transcortical/trans-sulcal approach is a safe approach for the access of deep-seated intraventricular lesions. The use of tubular retractor systems minimizes retraction injury when passing through the cortex and deep white matter tracts. This allows a decrease in the pressure on brain tissue that can occlude the brain vessels and produce local ischemia and a consequent permanent neurological injury. Case description: This is a case of a 66-year-old woman who presented chronic headaches that increased in frequency in the last month. Enhanced-brain MRI demonstrated a large left ventricular lesion with signs of obstructive hydrocephalus. Procedure: Patient was positioned supine. A bicoronal incision was used to perform a left frontal craniotomy. An F1/F2 transcortical/trans-sulcal approach was used. A guided tubular retractor is placed with the neuronavigation pointer, inserting it directly into the brain parenchyma and fixing it to the Leyla support. Postoperative postcontrast MRI demonstrated a complete resection of the tumor. Histopathological analysis revealed a subependymoma (World Health Organization Grade I). The patient presented transient apathy and loss of urinary sphincter control that completely resolved 3 weeks after surgery. Written informed consent was obtained for publication of information used for this work. Conclusions: A complete microsurgical resection of a large left ventricular subependymoma is feasible through a trans-sulcal tubular approach.

Neuronavegación asociada a resonancia funcional motora, validación por estimulación cortical directa en cirugías de tumores de área motora / Neuronavigation associated with functional motor resonance, validation by direct cortical stimulation in motor area tumor surgeries

Objetivo: Determinar la confiabilidad de rm funcional motora (rmfm) en la localización de la corteza motora primaria en condiciones patológicas causadas por la proximidad de lesiones expansivas cerebrales con el uso intraoperatorio de electro estimulación cortical directa (ecd) Material y método: Se incluyeron 48 pacientes portadores de tumores intra axiales (nº 25) y extraaxiales (nº23) próximas al área motora, con capacidad de realizar la tarea funcional motora por rmf, y que fueron sometidos a cirugía con ecd. Durante la cirugía se realizaron 220 registros de ecd en total de la población de pacientes estudiados. La población estuvo constituida por una serie consecutiva de casos, el estudio se planificó de manera prospectiva entre los años 2007-2019, y tiene como objetivo la evaluación de la eficacia de pruebas diagnósticas (stard 2015).Se realizó una comparación sitio por sitio entre la imagen por rmfm y la ecm con la ayuda del neuronavegador. Discusión: Los resultados estadísticos de la prueba fueron: sensibilidad 82.2%, Especificidad: 76,5%, lr+:3.49, Lr-: 0,23; vpp: 74.8%, Vpn: 83.5%; Odds Postest+:2.96, Odds postest-: 0,19 y fueron publicados acordes con los standards stard 2015. Conclusiones: Las técnicas de rmfm basadas en tareas, no son suficientes para la toma de decisiones críticas intraoperatorias. No obstante, la integración de la rmfm por neuronavegación implica una planificación espacial muy confiable que permite asociar el área de activación bold a la topografía del tumor y a la tractografía, de esta forma orientar una validación por ecd rápida y segura en la resección de los tumores cerebrales

Pure Endoscopic Excision of Parenchymal Brain Tumors: Feasibilty, Risks, Advantages and Realities - A Beginners Perspective

Background Neuroendoscopy is gaining popularity and is reaching new realms. Young neurosurgeons are exploring the various possibilities associated with the use of neuroendoscopy. Neuroendoscopy in excision of parenchymal brain tumors is less explored, and young neurosurgeons should be aware of the realities. The present article is an approach to put forward the difficulties faced by a young neurosurgeon and the lessons learnt. Objective To report the experience of surgical excision of parenchymal brain tumors, in selected cases, using pure endoscopic approach and to discuss its feasibility, technical benefits, risks and comparison with conventional microscopic excision. Method Eight patients of variable age group with parenchymal brain tumors were operated upon by a single surgeon and followed up for a period varying from6months to 2 years. Data regarding operating time, illumination, clarity of the field, size of craniotomy, blood loss and course of recovery was evaluated. All of the tumors were resected using rigid high definition zero and 30° endoscope. Results Out of eight cases, seven had lesions in the supratentorial and one in the infratentorial location. The age group ranged from 27 to 74 years old. Near to gross total resection was achieved in all except two cases. All of the patients recovered well without any significant morbidity or mortality. Hospital stay was reduced by 1 day on average. Conclusion Excision of parenchymal brain tumors via pure endoscopic method is a safe and efficient procedure. Although there is an initial period of learning curve, it is not steep for those already practicing neuroendoscopy, but the approach has its advantages.

Comparison of outcomes of free-hand 2-dimensional ultrasound-guided versus navigated 3-dimensional ultrasound-guided biopsy for supratentorial tumours: a single-institution experience with 125 cases

PURPOSE: The purpose of this study was to evaluate the relative utility and benefits of free-hand 2-dimensional intraoperative ultrasound (FUS) and navigated 3-dimensional intraoperative ultrasound (NUS) as ultrasound-guided biopsy (USGB) techniques for supratentorial lesions. METHODS: All patients who underwent USGB for suspected supratentorial tumours from January 2008 to December 2017 were retrospectively analyzed. The charts and electronic medical records of these patients were studied. Demographic, surgical, and pathological variables were collected and analyzed. The study group consisted of patients who underwent either FUS or NUS for biopsy. RESULTS: A total of 125 patients (112 adults and 13 children) underwent USGB during the study period (89 FUS and 36 NUS). NUS was used more often for deep-seated lesions (58% vs. 18% for FUS, P<0.001). The mean operating time for NUS was longer than for FUS (156 minutes vs. 124 minutes, P=0.001). Representative yield was found in 97.7% of biopsies using FUS and in 100% of biopsies using NUS (diagnostic yield, 93.6% and 91.3%, respectively). The majority of lesions (89%) were high-grade gliomas or lymphomas. Postoperative complications were more common in the NUS group (8.3% vs. 1.2%), but were related to the tumour location (deep). CONCLUSION: Despite the longer operating time and higher rate of postoperative complications, NUS has the benefit of being suitable for biopsies of deep-seated supratentorial lesions, while FUS remains valuable for superficial lesions.

Surgical Outcomes of Thalamic Tumors in Children: The Importance of Diffusion Tensor Imaging, Neuro-Navigation and Intraoperative Neurophysiological Monitoring

BACKGROUND: Recently, modern technology such as diffusion tensor imaging (DTI), neuro-navigation and intraoperative neurophysiological monitoring (IOM) have been actively adopted for the treatment of thalamic tumors. We evaluated surgical outcomes and efficacy of the aforementioned technologies for the treatment of pediatric thalamic tumors. METHODS: We retrospectively reviewed clinical data from 37 children with thalamic tumors between 2004 and 2017. There were 44 operations (27 tumor resections, 17 biopsies). DTI was employed in 17 cases, neuro-navigation in 23 cases and IOM in 14 cases. All diagnoses were revised according to the 2016 World Health Organization Classification of Tumors of the Central Nervous System. Progression-free survival (PFS) and overall survival (OS) rates were calculated, and relevant prognostic factors were analyzed. The median follow-up duration was 19 months. RESULTS: Fifteen cases were gross total resections (GTR), 6 subtotal resections (STR), and 6 partial resections (PR). Neurological status did not worsen after 22 tumor resections. There were statistically significant differences in terms of the extent of resection between the groups with DTI, neuro-navigation and IOM (n=12, GTR or STR=12) and the group without at least one of the three techniques (n=15, GTR or STR=9, p=0.020). The mean PFS was 87.2±38.0 months, and the mean OS 90.7±36.1 months. The 5-year PFS was 37%, and the 5-year OS 47%. The histological grade (p≤0.001) and adjuvant therapy (done vs. not done, p=0.016) were significantly related to longer PFS. The histological grade (p=0.002) and the extent of removal (GTR/STR vs. PR/biopsy, p=0.047) were significantly related to longer OS. CONCLUSION: Maximal surgical resection was achieved with acceptable morbidity in children with thalamic tumors by employing DTI, neuro-navigation and IOM. Maximal tumor resection was a relevant clinical factor affecting OS; therefore, it should be considered the initial therapeutic option for pediatric thalamic tumors.

Biopsia endoscópica de osteocondroma de fosa infratemporal / Endoscopic biopsy of infratemporal fossa osteochondroma

Presentamos el caso de una mujer de 13 años con un gran tumor de características óseas en la fosa infratemporal derecha, el cual fue biopsiado mediante un abordaje endoscópico transeptal transpterigoídeo. La biospia mostró un osteocondroma. Describimos el caso y discutimos sus aspectos relevantes.

We report the case of a 13-year-old woman with a large tumor with osseous appearance in her right infratemporal fossa, which was biopsied through an endoscopic transpterygoid approach. The biopsy showed an osteocondroma. We described the case and discuss its relevant aspects.

State of education regarding ultrasound-guided interventions during pain fellowships in Korea: a survey of recent fellows

BACKGROUND: Recently, the use of ultrasound (US) techniques in regional anesthesia and pain medicine has increased significantly. However, the current extent of training in the use of US-guided pain management procedures in Korea remains unknown. The purpose of the present study was to assess the current state of US training provided during Korean Pain Society (KPS) pain fellowship programs through the comparative analysis between training hospitals. METHODS: We conducted an anonymous survey of 51 pain physicians who had completed KPS fellowships in 2017. Items pertained to current US practices and education, as well as the types of techniques and amount of experience with US-guided pain management procedures. Responses were compared based on the tier of the training hospital. RESULTS: Among the 51 respondents, 14 received training at first- and second-tier hospitals (Group A), while 37 received training at third-tier hospitals (Group B). The mean total duration of pain training during the 1-year fellowship was 7.4 months in Group A and 8.4 months in Group B. Our analysis revealed that 36% and 40% of respondents in Groups A and B received dedicated US training, respectively. Most respondents underwent US training in patient-care settings under the supervision of attending physicians. Cervical root, stellate ganglion, piriformis, and lumbar plexus blocks were more commonly performed by Group B than by Group A (P < 0.05). CONCLUSIONS: Instruction regarding US-guided pain management interventions varied among fellowship training hospitals, highlighting the need for the development of educational standards that mandate a minimum number of US-guided nerve blocks or injections during fellowships in interventional pain management.

Neuronavegación en exéresis de linfangioma orbitario / Neuronavigation in exeresis of orbital lymphangioma

El linfangioma es un tumor benigno raro y predominante en la infancia, debido a su crecimiento puede comprometer al órgano donde se desarrolla, se han propuesto varias opciones de trata-miento, sin embargo, la cirugía continúa siendo la primera opción. La neuronavegación permite realizar exéresis con gran precisión y de utilidad en cirugía ocular, por lo que disminuye el riesgo de secuelas después de una exéresis de linfangioma orbitario.

Lymphangioma is a benign tumor predominantly in childhood, due to growth that can compromise the organ where it grows. Several treatment options, have been proposed however,surgery remains the first choice. Neuronavigation allows successful excision and use in eye surgery,which decreases the risk of sequels following excision of orbital lymphangioma.

The Role of the IntraoperativeAuxiliaryMethods in the Resection of Motor Area Lesions / O papel dos métodos auxiliares intraoperatórios na ressecção de lesões em área motora

Objective In recent years, technologies have advanced considerably in improving surgical outcome following treatment of lesions in eloquent brain areas. The aimof this study is to explore which method is best in the resection of motor area lesions. Methods Prospective, non-randomized study Evaluate on 74 patients who underwent surgery to remove lesions around the motor area. Results Total lesion removal was achieved in 68 patients (93.1%). Fifty-four patients (73.9%) presented normal motor function in the preoperative period; of these, 20 (37.3%) developed transitory deficits. Nevertheless, 85% of these patients later experienced a complete recovery. Nineteen patients presented with motor deficits preoperatively; of these, five presented deteriorating motor abilities. Intraoperative stimulation methods were used in 65% of the patients, primarily in cases of glioma. Conclusions The morbidity in patients submitted to resections of motor area lesions is acceptable and justify the surgical indication with the purpose of maximal resection. Intraoperative stimulation is an important tool that guides glioma resection in many cases.

Objetivo Nos últimos anos, consideráveis avanços tecnológicos têm surgido no sentido de melhorar os resultados cirúrgicos no tratamento de lesões em áreas eloquentes do cérebro. O objetivo deste estudo é investigar qual o melhor método para ressecção de lesões em área motora. Método Estudo prospectivo não aleatório que avaliou os resultados pós-operatórios em 74 pacientes submetidos à ressecção de lesões em área motora ou adjacente. Resultados A ressecção cirúrgica foi considerada total em 68 (93,1%) pacientes. 54 pacientes (73,9%) apresentavam força muscular normal no pré-operatório. Destes, 20 (37,3%) apresentaram déficit no pós-operatório imediato, sendo que 17 (85%) recuperaram completamente o déficit. 19 pacientes apresentavam déficit no préoperatório, sendo que 05 apresentaram piora do déficit no pós-operatório imediato. A estimulação intraoperatória foi utilizada em 65% dos casos, principalmente nos gliomas. Conclusão Amorbidade empacientes operados de lesões emáreamotora é bastante aceitável e justifica a indicação cirúrgica com objetivo de ressecção máxima. A estimulação intraoperatória é uma ferramenta importante para guiar a resseção dos gliomas em muitos casos.

Surgical exposure of the internal auditory canal through the retrosigmoid approach with semicircular canals anatomical preservation / Avaliação da exposição do fundo do conduto auditivo interno através do acesso retrosigmóide-transmeatal

Objective Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS). Method Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures. Results The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity. Conclusion A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals. .

Objetivo Avaliar a possibilidade de exposição adequada preservando anatomia das estruturas labirínticas pelo acesso retrosigmóide-transmeatal (RSA) nas ressecções de schwannomas do vestibular (VS). Método Trinta pacientes foram submetidos à ressecção cirúrgica e avaliados no pré-operatório com tomografias de alta definição e reconstruções de ressonância magnética 3D. A extensão da abertura do conduto auditivo interno (CAI) foi medida e confirmada com parâmetros de neuronavegação. No pós-operatório, a extensão da abertura e a integridade do labirinto foram confirmadas por imagens de tomografia computadorizada. Resultados A extensão do CAI no pré-operatório apresentou variação de 7,8-12 mm (média 9,3 mm, DP 0,98, IC95% de 8,9-9,6 e mediana 9 mm). Imagens pós-operatórias demonstraram abertura adequada do IAC e integridade dos canais semicirculares. Conclusão A abertura completa da parede posterior do CAI pelo RSA é possível e permite a visualização direta do fundo do conduto sem prejudicar os canais semicirculares. .

Image Guided Neurosurgery by Using Neuronavigation Integrated with Intraoperative Three-Dimensional Ultrasound.

Introduction: Intra-operative ultrasound provides low cost real time imaging that is simple and rapid to use. In recent years there has been a signifi cant improvement in the quality of ultrasound imaging. Ultrasound integrated neuronavigation can be used to optimize the approach, and achieving safe maximal resection, thereby improving outcomes for patients with diff erent localization and histology of brain tumors, vascular patology, spontaneous intra-cerebral hemorrhage. Material and Methods: Since 2007 till 2010, in the Institute of Neurology and Neurosurgery, 130 operations with application of 2D iUS have been performed. Starting from March till May 2012, 17 patients went under surgical treatment using the intraoperative ultrasound integrated neuronavigation system. Results: We applied ultrasound neuronavigation system in 17 cases on patients with diverse pathologies, including brain tumors (craniopharyngeoma, corpus callosum and intracerebral glioblastoma, intraaxial glioma), vascular patology (arteriovenous malformations, aneurysms), spontaneous intracerebral hemorrhage. Application of ultrasound neuronavigation system aids in improving postoperative outcomes for these patients. Conclusions: Th e integration of 3D US with neuronavigation technology created an effi cient and inexpensive tool for intraoperative imaging in neurosurgery. Th e technology has been applied to optimize surgery of brain tumors, but it has also been found to be useful in other procedures such as operations for aneurysms or arteriovenous malformations. iUS is easy to use and has a rapid learning curve which makes it a useful tool to the neurosurgeons intraoperative armamentarium.

Intraoperative neurosonography revisited: effective neuronavigation in pediatric neurosurgery

Intraoperative ultrasonography (IOUS) is a widely used noninvasive method to evaluate the morphology, vasculature, and pathologies of the brain. The advantages of IOUS include realtime depiction of neuroanatomy, accurate localization and characterization of a lesion, reduced surgical exploration and surgical time, and presumably decreased patient morbidity. IOUS is useful in the intraoperative monitoring of lesion resection as well as intraoperative localization and characterization of focal parenchymal lesions. This review aims to provide an overview of the clinical application of IOUS in pediatric intracranial neurosurgery.

Intraoperative high-field magnetic resonance imaging combined with functional neuronavigation in resection of low-grade temporal lobe tumors involving optic radiation / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the clinical value of high-field-strength intraoperative magnetic resonance imaging (iMRI) combined with optic radiation neuro-navigation for the resection of temporal lobe low-grade gliomas.</p><p><b>METHODS</b>From April 2009 to September 2013, 65 patients with temporal lobe low-grade gliomas (WHO grade II) involving optic radiation were operated with iMRI and functional neuro-navigation. Diffusion tensor imaging (DTI) based fiber tracking was used to delineate optic radiation. The reconstructed optic radiations were integrated into a navigation system, in order to achieve intraoperative microscopic-based functional neuro-navigation. iMRI was used to update the images for both optic radiations and residual tumors. Volumetric analyses were performed using 3D Slicer for pre- and intra-operative tumor volumes in all cases. All patients were evaluated for visual field deficits preoperatively and postoperatively. The Student t test was used to evaluate the average rate of extent of resection between groups. Spearman rank correlation analysis was used to assess correlations between predictors and epilepsy prognosis.</p><p><b>RESULTS</b>Preoperative tumor volumes were (78±40) cm3. In 29 cases, iMRI scan detected residual tumor that could be further resected, and extent of resection were increased from 76.2% to 92.7% (t=7.314, P<0.01). In 19 cases (29.2%), gross total resection was accomplished, and iMRI contributed directly to 8 of these cases. Postsurgical follow-up period varied from 13 months to 59 months, mean (33±13) months. Tumor progression were observed in 3 patients, newly developed or deteriorated visual field defects occurred in 4 patients (6.2%). For patients with pre-operative seizures, Engel Class I were achieved for 89.7% of them. Spearman rank correlation analysis revealed that seizure outcome (Engel Class) was related to increased excision of ratio (r=-0.452, P=0.004, 95% CI: -0.636--0.261) and larger tumors (r=0.391, P=0.014, 95% CI: 0.178-0.484).</p><p><b>CONCLUSIONS</b>With iMRI and functional neuro-navigation, the optic radiation can be accurately located, while extent of resection can be evaluated intra-operatively. This technique is safe and helpful for preservation of visual field for the resection of temporal lobe low-grade gliomas involving optic radiation.</p>

Clinical Experience of Glioma Surgery Using "Tailed Bullet": Overcoming the Limitations of Conventional Neuro-Navigation Guided Surgery

PURPOSE: Although conventional neuro-navigation is a useful tool for image-guided glioma surgery, there are some limitations, such as brain shift. We introduced our methods using an identifiable marker, a "tailed bullet", to overcome the limitation of conventional neuro-navigation. A tailed bullet is an identifiable tumor location marker that determines the extent of a resection and we have introduced our technique and reviewed the clinical results. MATERIALS AND METHODS: We have developed and used "tailed bullets" for brain tumor surgery. They were inserted into the brain parenchyma or the tumor itself to help identify the margin of tumor. We retrospectively reviewed surgically resected glioma cases using "tailed bullet". Total 110 gliomas included in this study and it contains WHO grade 2, 3, and 4 glioma was 14, 36, and 60 cases, respectively. RESULTS: Gross total resection (GTR) was achieved in 71 patients (64.5%), subtotal resection in 36 patients (32.7%), and partial resection in 3 patients (2.7%). The overall survival (OS) duration of grade 3 and 4 gliomas were 20.9 (range, 1.2-82.4) and 13.6 months (range, 1.4-173.4), respectively. Extent of resection (GTR), younger age, and higher initial Karnofsky Performance Status (KPS) score were related to longer OS for grade-4 gliomas. There was no significant adverse event directly related to the use of tailed bullets. CONCLUSION: Considering the limitations of conventional neuro-navigation methods, the tailed bullets could be helpful during glioma resection. We believe this simple method is an easily accessible technique and overcomes the limitation of the brain shift from the conventional neuro-navigation. Further studies are needed to verify the clinical benefits of using tailed bullets.

Cryptococcal Brainstem Abscess Mimicking Brain Tumors in an Immunocompetent Patient

Usually fungal infections caused by opportunistic and pathogenic fungi had been an important cause of morbidity and mortality among immunocompromised patients. However clinical data and investigations for immunocompetent pathogenic fungal infections had been rare and neglected into clinical studies. Especially Cryptococcal brainstem abscess cases mimicking brain tumors were also much more rare. So we report this unusual case. This 47-year-old man presented with a history of progressively worsening headache and nausea for 1 month and several days of vomituritions before admission. Neurological and laboratory examinations performed demonstrated no abnormal findings. Previously he was healthy and did not have any significant medical illnesses. A CT and MRI scan revealed enhancing 1.8x1.7x2.0 cm mass lesion in the left pons having central necrosis and peripheral edema compressing the fourth ventricle. And also positron emission tomogram scan demonstrated a hot uptake of fluoro-deoxy-glucose on the brainstem lesion without any evidences of systemic metastasis. Gross total mass resection was achieved with lateral suboccipital approach with neuronavigation system. Postoperatively he recovered without any neurological deficits. Pathologic report confirmed Cryptococcus neoformans and he was successively treated with antifungal medications. This is a previously unreported rare case of brainstem Cryptococcal abscess mimicking brain tumors in immunocompetent host without having any apparent typical meningeal symptoms and signs with resultant good neurosurgical recovery.