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.

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.

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.

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.

Resultados de la cirugía de los somatotropinomas por acceso transnasal endoscópico usando la técnica de neuronavegación / Results of somatotropinoma surgery through endoscopic transnasal approach using the neuronavigation technique

Introducción: El tratamiento de elección para los tumores hipofisarios productores de hormona de crecimiento es la cirugía. El por ciento de recurrencia es elevado, pero, en gran medida, está en relación con la experiencia de los cirujanos, la técnica empleada y el trabajo multidisciplinario. Desde el año 2011 se constituyó un equipo multidisciplinario para guiar la conducta y el seguimiento de estos pacientes, que serían intervenidos empleando la técnica endoscópica con neuronavegación. Objetivo: describir los resultados de la cirugía de los adenomas hipofisarios productores de hormona de crecimiento con la técnica de neuronavegación. Métodos: estudio descriptivo que incluyó la revisión de las historias clínicas de 18 pacientes con tumores hipofisarios productores de la hormona de crecimiento, evaluados y remitidos para tratamiento quirúrgico endoscópico con neuronavegación. Las variables analizadas fueron: la edad, el sexo, la prueba de tolerancia a la glucosa para medir hormona de crecimiento antes y 7 días después de la cirugía, las características del tumor, las complicaciones posquirúrgicas y la evolución. Resultados: de los 18 casos, 66,6 por ciento eran del sexo masculino. El 33,4 por ciento tenía un tumor con crecimiento hacia el suelo de la silla turca, y las complicaciones posquirúrgicas fueron mínimas: el 16,7 por ciento presentó una diabetes insípida transitoria, e igual porcentaje una fístula de líquido cefalorraquídeo. En el 55 por ciento se identificó la remisión bioquímica a la semana de la intervención. Conclusiones: la cirugía de tumores hipofisarios productores de hormona de crecimiento empleando la técnica endoscópica con neuronavegador ofrece ventajas para los pacientes, con una evolución satisfactoria desde el punto de vista clínico y bioquímico, así como una baja frecuencia de complicaciones(AU)

Introduction: Treatment of choice for growth hormone-producing hypophysial tumors is surgery. The recurrence percentage is high but, to a great extent, is related to the surgeon´s experience, the surgical technique and the multidisciplinary work. Since 2011, a multidisciplinary team was created to guide the behavior and the follow-up of these patients who would be operated on by using the endoscopic technique based on the neuronavigation. Objective: to describe the results of the growth hormone-producing hypophysial adenomas surgery by using the neuronavigation technique. Methods: a descriptive study that included checking of the medical records of 18 patients diagnosed with growth hormone-producing hypophysial tumors and referred for endoscopic surgical treatment through neuronavigation. The analyzed variables were age, sex, tolerance test for glucose to measure growth hormone before and 7 days after surgery, the characteristics of the tumor, the postsurgical complications and the progress. Results: of this group of 18 patients, 66.6 percent were males 33.4 percent had tumors growing into the floor of the Turkish saddle and the postsurgical complications were minimal: 16.7 percent presented with transient diabetes insipidus and the same percentage had a cerebrospinal fluid fistula. Biochemical remission was detected in 55 percent of patients one week after the surgery. Conclusions: growth hormone-producing hypophysial tumors surgery using the endoscopic technique with neuronavigator provides advantages for patients, with satisfactory recovery from the clinical and biochemical viewpoint as well as low frequency of complications(AU)

Cerebral biopsy: comparison between frame-based stereotaxy and neuronavigation in an oncology center / Biópsia cerebral: comparação entre estereotaxia com arco e neuronavegação em um centro de oncologia

Treatment of intracranial tumoral lesions is related to its correct histological diagnostic. We present a retrospective analysis of 32 patients submitted to 36 cerebral biopsies using neuronavigation and 44 patients using frame-based stereotaxy. Mean age was 46.6 and 49.3 years old respectively. Sex distribution in both groups was 50 percent for each. Most of lesions were lobar in both groups. Diagnostic yielding was 91.7 percent and 83.4 percent, respectively (p=0.26). We found in the postoperative CT scans intracranial hemorrhages in 13.8 percent cases of the first group and 9.8 percent cases in the second. Most of them were mild post-operative hemorrages in the biopsy site. There was one death related to the procedure in each group. Astrocytomas and metastatic adenocarcinomas were the most frequent diagnosis. Diagnostic yielding and the number of postoperative hemorrhage and death were similar on both groups and the same found in the literature.

O manejo das lesões intracranianas tumorais está relacionado ao seu diagnóstico histológico adequado. Foi realizado estudo retrospectivo com 32 pacientes submetidos a 36 biópsias cerebrais por neuronavegação e 44 pacientes por estereotaxia com arco. A idade média foi 46,6 e 49,3 anos respectivamente. Nos dois grupos a distribuição por sexo foi 50 por cento para cada. A maioria das lesões biopsiadas eram lobares nos dois grupos. A positividade diagnóstica foi 91,7 por cento para neuronavegação e 83,4 por cento para a estereotaxia com arco, respectivamente (p=0,26). Identificou-se hemorragia intracraniana na TC pós-operatória em 13,8 por cento dos casos no primeiro grupo e em 9,8 por cento no segundo, a maioria de pequena monta sem provocar piora neurológica. Ocorreu uma morte relacionada ao procedimento em cada grupo. Os diagnósticos mais freqüentes foram astrocitomas e adenocarcinomas metastáticos. A positividade diagnóstica, taxas de hemorragia pós-operatória e de mortalidade foram equiparáveis estatisticamente entre os dois métodos e se assemelham com as descritas na literatura.

Planificación quirúrgica avanzada en neurocirugía: metodología de procesamiento de imágenes integradas / Advanced surgical planning in neurosurgery: methodology of integrated image processing

El riesgo de provocar morbilidad incapacitante y permanente en el paciente neuroquirúrgico ha sido el motor del desarrollo de la imagenología actual. Además de la adquisición de imágenes anatómicas muy detalladas, hoy se puede tener información funcional para cada paciente individual y utilizarla para la planificación del abordaje quirúrgico. La integración de esta información y su utilización racional en un sistema de despliegue tridimensional es el objetivo final de todo el estudio preoperatorio del paciente. La capacidad que tenga el neurocirujano de evaluar esta información antes y durante el acto quirúrgico son determinantes en el resultado. Se analizan la integración de imágenes derivadas de la TAC RM funcional, anatómica y tractografía en la evaluación preoperatoria. A pesar de que la tecnología está ampliamente disponible y al alcance, el conocimiento sobre su empleo correcto para el manejo rutinario no siempre está presente. Actualmente la mayoría de los clínicos deben revisar interminables secuencias de cortes para efectuar una reconstrucción mental del problema del paciente, y con esta información enfrentar el caso. El desafío educacional actual es incorporar el manejo de esta tecnología en la práctica clínica rutinaria, para construir una memoria organizacional que sea capaz de mantener el ritmo de avance que cada vez parece más acelerado.

The risk of incapacitating and permanent morbidity in the neurosurgical patient has driven modern times medical imaging. Besides rich anatomical images, today we can have functional information about the individual patient, to be used in pre-operative planning. The integration of this information for its rational use in a three dimensional planning system is the final goal of all the preoperative study of the patient. The capacity of the neurosurgeon to evaluate and use this information during the actual surgical procedure is determinant in the results. The integration of images from computed tomography, magnetic resonance, anatomic and functional, and lately tractography are analyzed. Although the technology is widely available, knowledge about its use is lacking in the clinical field. Many neurosurgeons still must review hundreds of slices to make a mental composition of the pathology and the anatomy and with this, plan the operation. The challenge is to incorporate this technology in routine clinical practice, to build enough organizational memory to keep pace with the fast rhythm imposed by progress in neuroimaging.

Software para planificación de neurocirugías y su aplicación en una cirugía estereotáxica de aracnoidocele / Neurosurgery planning software and its application in a stereotactic surgery of arachnoidocele

El soporte tecnológico a través de equipos y aplicaciones médicas especializadas se ha convertido en una necesidad en el área de la neurocirugía. Frecuentemente, el neurocirujano utiliza sistemas asistidos por computador y neuronavegadores como herramientas auxiliares durante las fases pre-operatoria e intra-operatoria de la cirugía. Estas herramientas tecnológicas permiten planificar el abordaje quirúrgico de una forma rápida, eficiente e interactiva, facilitando también el uso de técnicas quirúrgicas de mínima invasión, como la cirugía estereotáxica. En este trabajo se presenta la utilización del software para neuronavegación que desarrollamos, en la planificación pre-operatoria de una intervención con marco estereotáxico para remover una lesión de aracnoidocele. El software soporta el manejo de imágenes e información conforme con el estándar DICOM, la visualización directa de datos volumétricos con mapeo de texturas 2D y 3D, el despliegue de imágenes multimodales y la segmentación de estructuras anatómicas, permitiendo al neurocirujano definir la trayectoria y el protocolo del abordaje quirúrgico mientras efectúa la navegación simulada sobre la anatomía del paciente.

In the neurosurgery field, the technological support through specialized equipment and medical applications has become a need. Neurosurgeons often make use of computer assisted systems and neuronavigators as auxiliary tools during the preoperative and intraoperative phases of the surgery. These technological resources allow them to plan the surgical approach in a fast, efficient and interactive way; also, making minimally invasive surgical techniques, such as stereotactic surgery, easier to use. In this work, we present the use of a neuronavigation medical application we developed in the preoperative planning of a frame-based stereotactic procedure to remove an arachnoidocele lesion. This software features support for handling images and information in conformance with the DICOM standard, direct rendering of volumetric data through 2D and 3D texture mapping, displaying of multimodal images and the segmentation of anatomical structures. By using the planning software, neurosurgeons can define the surgical approach protocol and trajectory, while doing the simulated navigation through the patient anatomy.

Neuronavigation: concept, techniques and applications.

Neuronavigation provides intraoperative orientation to the surgeon, helps in planning a precise surgical approach to the targetted lesion and defines the surrounding neurovascular structures. Incorporation of the functional data provided by functional MRI and magnetoencephalography (MEG) with neuronavigation helps to avoid the eloquent areas of the brain during surgery. An intraoperative MRI enables radical resection of the lesions, the possibility of immediate control for tumor remnants and updates of neuronavigation with intraoperative images to compensate for brain shift. In this study, the experience of 432 patients undergoing neuronavigation assisted neurosurgical interventions using either the pointer-based or microscope-based navigational systems at the University of Erlangen-Nuremberg, Germany is presented. The procedures included stereotactic biopsy (n=53), stereotactic cyst puncture/ventricular drainage (n=15), eloquent cortex/tumor localization to facilitate tumor resection, assessment of neurovascular structures in the vicinity of tumors of the sellar-suprasellar regions, skull base, posterior fossa and ventricular region (n=252), and, surgery for epilepsy (n=9). Functional brain mapping using fMRI and MEG and their integration with neuronavigation was carried out in 24 and 128 patients respectively. The simultaneous use of intraoperative MRI to look for the remaining tumor was done in 159 patients and the update of navigational data was carried out in 17 patients. The mean system accuracy obtained by using both the fiducial registration as well as anatomical landmark-surface fitting computer algorithm was 1.81 mm. This study reviews the relative merits and demerits of the pointer and microscope based navigational systems and also highlights the role of functional brain mapping and intraoperative MRI, when integrated with neuronavigation, in the surgical decision-making to offer the chances of more radical resections with minimal morbidity.