Showing papers on "Neuronavigation published in 2015"

Advances in diagnosis and treatment of trigeminal neuralgia.

Abstract: Various drugs and surgical procedures have been utilized for the treatment of trigeminal neuralgia (TN). Despite numerous available approaches, the results are not completely satisfying. The need for more contemporaneous drugs to control the pain attacks is a common experience. Moreover, a number of patients become drug resistant, needing a surgical procedure to treat the neuralgia. Nonetheless, pain recurrence after one or more surgical operations is also frequently seen. These facts reflect the lack of the precise understanding of the TN pathogenesis. Classically, it has been related to a neurovascular compression at the trigeminal nerve root entry-zone in the prepontine cistern. However, it has been evidenced that in the pain onset and recurrence, various neurophysiological mechanisms other than the neurovascular conflict are involved. Recently, the introduction of new magnetic resonance techniques, such as voxel-based morphometry, diffusion tensor imaging, three-dimensional time-of-flight magnetic resonance angiography, and fluid attenuated inversion recovery sequences, has provided new insight about the TN pathogenesis. Some of these new sequences have also been used to better preoperatively evidence the neurovascular conflict in the surgical planning of microvascular decompression. Moreover, the endoscopy (during microvascular decompression) and the intraoperative computed tomography with integrated neuronavigation (during percutaneous procedures) have been recently introduced in the challenging cases. In the last few years, efforts have been made in order to better define the optimal target when performing the gamma knife radiosurgery. Moreover, some authors have also evidenced that neurostimulation might represent an opportunity in TN refractory to other surgical treatments. The aim of this work was to review the recent literature about the pathogenesis, diagnosis, and medical and surgical treatments, and discuss the significant advances in all these fields.

A Simplified Method of Accurate Postprocessing of Diffusion Tensor Imaging for Use in Brain Tumor Resection.

Abstract: Use of diffusion tensor imaging (DTI) in brain tumor resection has been limited in part by a perceived difficulty in implementing the techniques into neurosurgical practice. To demonstrate a simple DTI postprocessing method performed without a neuroscientist and to share results in preserving patient function while aggressively resecting tumors. DTI data are obtained in all patients with tumors located within presumed eloquent cortices. Relevant white matter tracts are mapped and integrated with neuronavigation by a nonexpert in < 20 minutes. We report operative results in 43 consecutive awake craniotomy patients from January 2014 to December 2014 undergoing resection of intracranial lesions. We compare DTI-expected findings with stimulation mapping results for the corticospinal tract, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus. Twenty-eight patients (65%) underwent surgery for high-grade gliomas and 11 patients (26%) for low-grade gliomas. Seventeen patients had posterior temporal lesions; 10 had posterior frontal lesions; 8 had parietal-temporal-occipital junction lesions; and 8 had insular lesions. With DTI-defined tracts used as a guide, a combined 65 positive maps and 60 negative maps were found via stimulation mapping. Overall sensitivity and specificity of DTI were 98% and 95%, respectively. Permanent speech worsening occurred in 1 patient (2%), and permanent weakness occurred in 3 patients (7%). Greater than 90% resection was achieved in 32 cases (74%). Accurate DTI is easily obtained, postprocessed, and implemented into neuronavigation within routine neurosurgical workflow. This information aids in resecting tumors while preserving eloquent cortices and subcortical networks. DEC, directionally encoded color DTI, diffusion tensor imaging FA, fractional anisotropy IFOF, inferior fronto-occipital fasciculus SLF, superior longitudinal fasciculus

Minimally invasive evacuation of parenchymal and ventricular hemorrhage using the Apollo system with simultaneous neuronavigation, neuroendoscopy and active monitoring with cone beam CT

Abstract: Introduction The Apollo system is a low profile irrigation–aspiration system which can be used for the evacuation of intracranial hemorrhage. We demonstrate the feasibility of using Apollo to evacuate intracranial hemorrhage in a series of three patients with combined neuronavigation, neuroendoscopy, and cone beam CT (CB-CT). Methods Access to the hematoma was planned using neuronavigation software. Parietal (n=2) or frontal (1) burr holes were created and a 19 F endoscopic sheath was placed under neuronavigation guidance into the distal aspect of the hematoma along its longest accessible axis. The 2.6 mm Apollo wand was then directed through the working channel of a neuroendoscope and used to aspirate the blood products under direct visualization, working from distal to proximal. After a pass through the hematoma, the sheath, neuroendoscope, and Apollo system were removed. CB-CT was then used to evaluate for residual hematoma. When required, the CB-CT data could then be directly uploaded into the neuronavigation system and a new trajectory planned to approach the residual hematoma. Results Three patients with parenchymal (n=2) and mixed parenchymal–intraventricular (n=1) hematomas underwent minimally invasive evacuation with the Apollo system. The isolated parenchymal hematomas measured 93.4 and 15.6 mL and were reduced to 11.2 (two passes) and 0.9 mL (single pass), respectively. The entire parenchymal component of the mixed hemorrhage was evacuated, as was the intraventricular component within the right frontal horn (single pass). No complications were experienced. All patients showed clinical improvement after the procedure. The average presenting National Institutes of Health Stroke Scale was 19.0, which had improved to 5.7 within an average of 4.7 days after the procedure. Conclusions The Apollo system can be used within the neuroangiography suite for the minimally invasive evacuation of intracranial hemorrhage using simultaneous neuronavigation for planning and intraprocedural guidance, direct visualization with neuroendoscopy, and real time monitoring of progress with CB-CT.

Endoscopy-assisted interhemispheric transcallosal hemispherotomy: preliminary description of a novel technique

Abstract: Background Various hemispherotomy techniques have been developed to reduce complication rates and achieve the best possible seizure control. Objective To present a novel and minimally invasive endoscopy-assisted approach to perform this procedure. Methods Endoscopy-assisted interhemispheric transcallosal hemispherotomy was performed in 5 children (April 2013-June 2014). The procedure consisted of performing a small craniotomy (4 × 3 cm) just lateral to midline using a transverse skin incision. After dural opening, the surgery was performed with the assistance of a rigid high-definition endoscope, and bayoneted self-irrigating bipolar forceps and other standard endoscopic instruments. Steps included a complete corpus callosotomy followed by the disconnection of the hemisphere at the level of the basal nuclei and thalamus. The surgeries were performed in a dedicated operating room with intraoperative magnetic resonance imaging and neuronavigation. Intraoperative magnetic resonance imaging confirmed a total disconnection. Results The pathologies for which surgeries were performed included sequelae of middle a cerebral artery infarct (n = 2), Rasmussen syndrome (n = 1), and hemimegalencephaly (2). Four patients had an Engel class I and 1 patient had a class II outcome at a mean follow-up of 10.2 months (range, 3-14 months). The mean blood loss was 80 mL, and mean operating time was 220 minutes. There were no complications in this study. Conclusion This study describes a pilot novel technique and the feasibility of performing a minimally invasive, endoscopy-assisted hemispherotomy.

Transsphenoidal Approach in Endoscopic Endonasal Surgery for Skull Base Lesions: What Radiologists and Surgeons Need to Know.

Abstract: In the last 2 decades, endoscopic endonasal transsphenoidal surgery has become the most popular choice of neurosurgeons and otolaryngologists to treat lesions of the skull base, with minimal invasiveness, lower incidence of complications, and lower morbidity and mortality rates compared with traditional approaches. The transsphenoidal route is the surgical approach of choice for most sellar tumors because of the relationship of the sphenoid bone to the nasal cavity below and the pituitary gland above. More recently, extended approaches have expanded the indications for transsphenoidal surgery by using different corridors leading to specific target areas, from the crista galli to the spinomedullary junction. Computer-assisted surgery is an evolving technology that allows real-time anatomic navigation during endoscopic surgery by linking preoperative triplanar radiologic images and intraoperative endoscopic views, thus helping the surgeon avoid damage to vital structures. Preoperative computed tomography is the preferred modality to show bone landmarks and vascular structures. Radiologists play an important role in surgical planning by reporting extension of sphenoid pneumatization, recesses and septations of the sinus, and other relevant anatomic variants. Radiologists should understand the relationships of the sphenoid bone and skull base structures, anatomic variants, and image-guided neuronavigation techniques to prevent surgical complications and allow effective treatment of skull base lesions with the endoscopic endonasal transsphenoidal approach.

Introduction of a standardized multimodality image protocol for navigation-guided surgery of suspected low-grade gliomas.

Abstract: OBJECT Surgery of suspected low-grade gliomas (LGGs) poses a special challenge for neurosurgeons due to their diffusely infiltrative growth and histopathological heterogeneity. Consequently, neuronavigation with multimodality imaging data, such as structural and metabolic data, fiber tracking, and 3D brain visualization, has been proposed to optimize surgery. However, currently no standardized protocol has been established for multimodality imaging data in modern glioma surgery. The aim of this study was therefore to define a specific protocol for multimodality imaging and navigation for suspected LGG. METHODS Fifty-one patients who underwent surgery for a diffusely infiltrating glioma with nonsignificant contrast enhancement on MRI and available multimodality imaging data were included. In the first 40 patients with glioma, the authors retrospectively reviewed the imaging data, including structural MRI (contrast-enhanced T1-weighted, T2-weighted, and FLAIR sequences), metabolic images derived from PET, or MR spectroscopy chemical shift imaging, fiber tracking, and 3D brain surface/vessel visualization, to define standardized image settings and specific indications for each imaging modality. The feasibility and surgical relevance of this new protocol was subsequently prospectively investigated during surgery with the assistance of an advanced electromagnetic navigation system in the remaining 11 patients. Furthermore, specific surgical outcome parameters, including the extent of resection, histological analysis of the metabolic hotspot, presence of a new postoperative neurological deficit, and intraoperative accuracy of 3D brain visualization models, were assessed in each of these patients. RESULTS After reviewing these first 40 cases of glioma, the authors defined a specific protocol with standardized image settings and specific indications that allows for optimal and simultaneous visualization of structural and metabolic data, fiber tracking, and 3D brain visualization. This new protocol was feasible and was estimated to be surgically relevant during navigation-guided surgery in all 11 patients. According to the authors' predefined surgical outcome parameters, they observed a complete resection in all resectable gliomas (n = 5) by using contour visualization with T2-weighted or FLAIR images. Additionally, tumor tissue derived from the metabolic hotspot showed the presence of malignant tissue in all WHO Grade III or IV gliomas (n = 5). Moreover, no permanent postoperative neurological deficits occurred in any of these patients, and fiber tracking and/or intraoperative monitoring were applied during surgery in the vast majority of cases (n = 10). Furthermore, the authors found a significant intraoperative topographical correlation of 3D brain surface and vessel models with gyral anatomy and superficial vessels. Finally, real-time navigation with multimodality imaging data using the advanced electromagnetic navigation system was found to be useful for precise guidance to surgical targets, such as the tumor margin or the metabolic hotspot. CONCLUSIONS In this study, the authors defined a specific protocol for multimodality imaging data in suspected LGGs, and they propose the application of this new protocol for advanced navigation-guided procedures optimally in conjunction with continuous electromagnetic instrument tracking to optimize glioma surgery.

Contemporary frameless intracranial biopsy techniques: Might variation in safety and efficacy be expected?

Abstract: Background Frameless stereotactic neuronavigation has proven to be a feasible technology to acquire brain biopsies with good accuracy and little morbidity and mortality. New systems are constantly introduced into the neurosurgical armamentarium, although few studies have actually evaluated and compared the diagnostic yield, morbidity, and mortality of various manufacturer’s frameless neuronavigation systems. The present study reports our experience with brain biopsy procedures performed using both the Medtronic Stealth TreonTM Vertek® and BrainLAB® Varioguide frameless stereotactic brain biopsy systems.

Multimodal navigated skull base tumor resection using image-based vascular and cranial nerve segmentation: A prospective pilot study.

Abstract: Skull base tumors frequently encase or invade adjacent normal neurovascular structures. For this reason, optimal tumor resection with incomplete knowledge of patient anatomy remains a challenge.To determine the accuracy and utility of image-based preoperative segmentation in skull base tumor resections, we performed a prospective study. Ten patients with skull base tumors underwent preoperative 3T magnetic resonance imaging, which included thin section three-dimensional (3D) space T2, 3D time of flight, and magnetization-prepared rapid acquisition gradient echo sequences. Imaging sequences were loaded in the neuronavigation system for segmentation and preoperative planning. Five different neurovascular landmarks were identified in each case and measured for accuracy using the neuronavigation system. Each segmented neurovascular element was validated by manual placement of the navigation probe, and errors of localization were measured.Strong correspondence between image-based segmentation and microscopic view was found at the surface of the tumor and tumor-normal brain interfaces in all cases. The accuracy of the measurements was 0.45 ± 0.21 mm (mean ± standard deviation). This information reassured the surgeon and prevented vascular injury intraoperatively. Preoperative segmentation of the related cranial nerves was possible in 80% of cases and helped the surgeon localize involved cranial nerves in all cases.Image-based preoperative vascular and neural element segmentation with 3D reconstruction is highly informative preoperatively and could increase the vigilance of neurosurgeons for preventing neurovascular injury during skull base surgeries. Additionally, the accuracy found in this study is superior to previously reported measurements. This novel preliminary study is encouraging for future validation with larger numbers of patients.

Neuronavigation-assisted percutaneous balloon compression for the treatment of trigeminal neuralgia: The technique and short-term clinical results

Abstract: Background. Percutaneous balloon compression (PBC) has been widely used in the treatment of trigeminal neuralgia. However, this technique has a steep learning curve and significant complications were reported that were related to foramen ovale puncturing. The aim of this study was to evaluate the clinical results of a small patient group who underwent neuronavigation-assisted PBC. Methods. An intraoperative computed tomography (CT) device (CereTom, Neurologica, Danvers, MA/USA) was used to obtain CT scans with 2-mm slice thicknesses. The data were transferred to a neuronavigation system planning station (BrainLab, Feldkirchen, Germany). A soft touch registration system was used for image registration. With the image guidance, a trajectory was defined and the foramen ovale was cannulated using neuronavigation and Hartel's landmarks. Results. Sixteen procedures were performed on 13 patients (4 female and 9 male) without complications. The total length of the procedure was not more than 57 min in all...

A 3D endoscopic transtubular transcallosal approach to the third ventricle

Abstract: OBJECT Surgical approaches to deep-seated brain pathologies, specifically lesions of the third ventricle, have always been a challenge for neurosurgeons. In certain cases, the transcallosal approach remains the most suitable option for targeting lesions of the third ventricle, although retraction of the fornices and wall of the third ventricle have been associated with neuropsychological and hypothalamic deficits. The authors investigated the feasibility of an interhemispheric 3D endoscopic transcallosal approach through a minimally invasive tubular retractor system for the management of third ventricular lesions. METHODS Three-dimensional endoscopic transtubular transcallosal approaches were performed on 5 preserved cadaveric heads (10 sides). A parasagittal bur hole was placed using neuronavigation, and a tubular retractor was inserted under direct endoscopic visualization. Following observation of the vascular structures, fenestration of the corpus callosum was performed and the retractor was advanced ...

Electromagnetic navigation-guided surgery in the semi-sitting position for posterior fossa tumours: a safety and feasibility study

Abstract: Electromagnetic (EM)-guided neuronavigation is an innovative technique and a viable alternative to opto-electric navigation. We have performed a safety and feasibility study using EM-guided neuronavigation for posterior fossa surgery in the semi-sitting position in a selected subset of patients. Out of 284 patients with posterior fossa tumours operated upon over a period of 40 months, a subset of 15 patients was thought to possibly benefit from EM navigational guidance and was included in this study. There were six children and nine adults (aged between 8 and 84 years; mean age, 34.6 years) with different neoplasms in the brainstem or close to the midline. All patients had contrast-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) of the head preoperatively. EM-guided navigation was used to identify and preserve the venous sinuses during craniotomy and to determine the trajectory to the lesion using various approaches. Neuronavigation accuracy was repeatedly checked for deviations measured in millimetres on screen shots during surgery before and after dural opening in the coronal (z = vertical), axial (x = mediolateral) and sagittal (y = anteroposterior) plane. Referencing of the patient in the supine position was fast and easy. There was no loss of navigation accuracy after repositioning of the patient in the semi-sitting position (mean, 2.5 mm ± 0.92 mm). Identification of the pathological structure using EM navigation was achieved in all instances. Optimal angulation of the neck was selected individually to permit a comfortable position for the surgeon with full access to the lesion avoiding over-flexion. Deviation of accuracy at the surface of the target lesion ranged between 2.5 and 5.8 mm (mean, 3.9 mm ± 1.1 mm). EM-guided neuronavigation in the semi-sitting position was safe and technically feasible. It enabled fast and accurate referencing without loss of navigation accuracy despite repositioning of the patient. In contrast to conventional opto-electric neuronavigation there were no line of sight problems.

Endoscopic epilepsy surgery: Emergence of a new procedure

Abstract: Background: The use of minimally invasive endoscopic surgery is fast emerging in many subspecialties of neurosurgery as an effective alternative to the open procedures. Objective: The author describe a novel technique of using an endoscope for performing a corpus callosotomy and hemispherotomy. A description of endoscopic disconnection for a hypothalamic hamartoma (HH) and a review of the literature is also presented. Materials and Methods: Thirty four patients underwent endoscopic procedures between January 2010 and March 2015. These included endoscopic-assisted inter-hemispheric trans-callosal hemispherotomy (EH; n = 11), endoscopic-assisted corpus callosotomy with anterior/posterior commissurotomy (CCWC; n = 16), and endoscopic disconnection for HH (n = 7). EH and CCWC were performed with the use of a small craniotomy (4 cm × 3 cm). The surgeries were performed using a rigid high-definition endoscope, bayonetted self-irrigating bipolar forceps, and other standard endoscopic instruments along with the guidance of intra-operative magnetic resonance imaging and neuronavigation. HH disconnection was performed using endoscopic neuronavigation through a burr hole. Results: Hemispherotomy: Sequelae of middle cerebral artery infarct (5), Rasmussen's syndrome (3), and hemimegalencephaly (3). Outcome: Class I Engel (9) and class II (2), mean follow-up of 8.4 months, range: 3-18 months. Mean blood loss: 85 cc, mean operating time: 210 min. CCWC: All had a diagnosis of Lennox-Gastaut syndrome (LGS), with etiologies of hypoxic insult (10), lissencephaly (2), bilateral band heterotropia (2), microgyria and pachygyria (2). Mean follow-up: 18 ± 4.7 (16-27 months). Drop attacks stopped in all the patients. Seizure frequency and duration decreased >90% (11) and >50% (5). HH: Type II (2), Type III (2), Type IV (3). 5 had IA outcome. Conclusion: The article emphasizes the role of endoscopic procedures for epilepsy surgery and provides a review of literature. This experience may subserve to coin the term endoscopic epilepsy surgery for a fast emerging subspeciality in the field of epilepsy surgery.

Subcortical mapping of calculation processing in the right parietal lobe

Abstract: Preservation of calculation processing in brain surgery is crucial for patients' quality of life. Over the last decade, surgical electrostimulation was used to identify and preserve the cortical areas involved in such processing. Conversely, subcortical connectivity among different areas implicated in this function remains unclear, and the role of surgery in this domain has not been explored so far. The authors present the first 2 cases in which the subcortical functional sites involved in calculation were identified during right parietal lobe surgery. Two patients affected by a glioma located in the right parietal lobe underwent surgery with the aid of MRI neuronavigation. No calculation deficits were detected during preoperative assessment. Cortical and subcortical mapping were performed using a bipolar stimulator. The current intensity was determined by progressively increasing the amplitude by 0.5-mA increments (from a baseline of 1 mA) until a sensorimotor response was elicited. Then, addition and mu...

The contralateral transfalcine transprecuneus approach to the atrium of the lateral ventricle: operative technique and surgical results.

Abstract: CONCLUSION: The contralateral transfalcine transprecuneus approach is appropriate for most lesions in the atrium of the lateral ventricle. It provides a wider surgical angle (especially for the lateral extension) and reduces the risk of disturbance of the optic radiation compared with the conventional approaches. The use of magnetic resonance venography-magnetic resonance imaging neuronavigation makes the procedure much easier and more accurate, and the neuroendoscope adds to the visualization of the microscope and can reduce surgical complications.

Resection of cerebral gangliogliomas causing drug-resistant epilepsy: short- and long-term outcomes using intraoperative MRI and neuronavigation.

Abstract: OBJECT Cerebral gangliogliomas (GGs) are highly associated with intractable epilepsy. Incomplete resection due to proximity to eloquent brain regions or misinterpretation of the resection amount is a strong negative predictor for local tumor recurrence and persisting seizures. A potential method for dealing with this obstacle could be the application of intraoperative high-field MRI (iopMRI) combined with neuronavigation. METHODS Sixty-nine patients (31 female, 38 male; median age 28.5 ± 15.4 years) suffering from cerebral GGs were included in this retrospective study. Five patients received surgery twice in the observation period. In 48 of the 69 patients, 1.5-T iopMRI combined with neuronavigational guidance was used. Lesions close to eloquent brain areas were resected with the implementation of preoperative diffusion tensor imaging tractography and blood oxygenation level–dependent functional MRI (15 patients). RESULTS Overall, complete resection was accomplished in 60 of 69 surgical procedures (87%). ...

[High-Definition Exoscope System for Microneurosurgery:Use of an Exoscope in Combination with Tubular Retraction and Frameless Neuronavigation for Microsurgical Resection of Deep Brain Lesions].

Abstract: The high-definition exoscope (VITOM®, Karl Storz GmbH & Co., Tuttlingen, Germany) is a new equipment that can be used as an alternative to the operating microscope in neurosurgery. Several neurosurgeons have recently reported that the exoscope allows for long working distances and great depth of field. Herein, we review reported cases of exoscope use in neurosurgery. We also describe the advantages of the exoscope compared to the operating microscope and endoscope. Furthermore, we introduce a novel technique for microsurgical resection of deep brain lesions, in which the exoscope is used along with tubular retraction and frameless neuronavigation. Before the operation, neuronavigation is registered and the surgical trajectory is planned to avoid damaging the functional cortex and eloquent white matter tracts. By using intraoperative neuronavigation, the tubular retractor (NICO BrainPath®, NICO Corporation, Indianapolis, US), which is designed to split the white matter when gently inserted, is inserted transcortically into the brain to reach the lesion, along the preplanned trajectory. After insertion, the tubular retractor is fixed in place using a self-retaining arm. This creates a narrow corridor that enables the use of the exoscope (for optimum visualization), bimanual dissection technique, and long bayoneted surgical instruments. The large focal distance of the exoscope allows it to be placed sufficiently further away from the surgical site, permitting the passage of long surgical instruments under the scope. Although obtaining surgical access to deep-seated brain lesions is challenging, we consider that this technique facilitates a safe surgical approach for lesions in deep locations.

Intraoperative neurosonography revisited: effective neuronavigation in pediatric neurosurgery.

Abstract: 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.

Use of intraoperative Doppler ultrasound with neuronavigation to guide arteriovenous malformation resection: a pediatric case series.

Abstract: OBJECT Over the last 20 years, several intraoperative adjuncts, including ultrasonography, neuronavigation, and angiography, have been said to aid the intraoperative localization and resection of cerebral arteriovenous malformations (AVMs). The authors assessed the value of intraoperative Doppler ultrasonography in conjunction with neuronavigation during surgery for cerebral AVMs in the pediatric population. METHODS The authors reviewed all cranial AVM resections performed by a single surgeon at their institution in the period from 2007 to 2013 and here describe their experience and results in a series of 20 consecutive AVM resections in 19 pediatric patients. Intraoperative Doppler ultrasonography had been used in conjunction with preoperative CT or neuronavigational MRI. Preoperative and postoperative clinical findings, patient age, and Spetzler-Martin AVM grade were identified in all patients. RESULTS All patients, whose ages ranged from 2 to 16 years, underwent craniotomy and excision of an AVM, which...

Does size matter? Minimally invasive approach in pediatric neurosurgery—a review of 125 minimally invasive surgeries in children: clinical history and operative results

Abstract: Surgery is an integral component and typically the first line of therapy for children with central nervous system tumors. Conventional aims of neurosurgery including tumor removal, management of hydrocephalus, and diagnostic sampling have been radically modified with innovative technologies such as navigational guidance, functional mapping, endoscopic surgery, second-look surgery, and physiologic imaging. The aim of the study was to investigate our operative results using minimally invasive technique in children. Clinical features, surgical technique and results, length of hospital stay, and complications were reviewed retrospectively. Pre- and early postoperative MRI was evaluated for degree of surgical resection. Correlation of tumor localization, lengths of hospital stay as well as surgical techniques and clinical outcome with follow-up was investigated. One hundred ten patients underwent 125 tumor resections using minimally invasive approaches (image- and functional guided tailored keyhole approaches for supratentorial, retrosigmoidal, and suboccipital keyhole approaches for infratentorial lesions). Most tumors were located supratentorial (62.4 %). In 29.6 % of the cases, the surgery was performed endoscope-assisted or endoscope-controlled; neuronavigation was used in 45.6 % and ultrasound in 24 % of the cases. Astrocytomas were diagnosed in 26.4 % of cases, ependymomas in 9.6 %, and medulloblastomas in 14.4 %. Gross total resection was achieved in 60.8 %. The most common complication was CSF fistula (n = 9), and the occurrence was significantly higher in younger children (p = 0.0001) and infratentorial located tumors (p = 0.02). Surgery for posterior fossa lesions was associated with a longer hospital stay (p = 0.02) compared to surgery of supratentorial lesions. Mean follow-up was 29.7 months (range 0.3–79.1 months), and most of the children recovered during the further course of the follow-up (symptoms better or idem in 74.4 %). In conclusion, our study shows that it is possible to achieve surgical results in the pediatric population applying minimal invasive techniques comparable to those described in the literature.

Application of MRI and intraoperative CT fusion images with integrated neuronavigation in percutaneous radiofrequency trigeminal rhizotomy

Abstract: Percutaneous radiofrequency trigeminal rhizotomy (RF-TR) has been an effective treatment modality for medically refractory trigeminal neuralgia. Our group has established a protocol for this procedure that includes intraoperative computed tomography (iCT) navigation. The depth of the puncture needle in our protocol was based on cadaveric studies, and anatomical localization was mainly by electric stimulation test. The limitation of the invisibility of the trigeminal cistern on CT imaging and bias from the patient’s subjective expression during neurophysiologic stimulation might affect the accuracy of the needle tip and the treatment effect.This study aimed to evaluate the feasibility and preliminary results of the application of magnetic resonance imaging (MRI) and iCT fusion imaging in RF-TR. The study included 13 patients who received RF-TR with iCT navigation and with recurrence within 3 years. Repeated RF-TR was performed with real-time guidance by MRI and iCT fusion imaging. A pain-free or partial satisfactory response was reported with 12 patients (92 %). There was a statistically significant difference in the depth of the needle tip before and after application of MRI and iCT fusion imaging. This preliminary study demonstrated that the application of MRI and iCT fusion could help with anatomical localization of the trigeminal cistern intraoperatively. The improvement in neuronavigation provides a choice in the treatment of recurrent or persistent trigeminal neuralgia after previous intervention. Long-term follow-up of the result is necessary to evaluate the benefit in terms of durability of therapeutic efficacy.