Showing papers on "Neuronavigation published in 2018"

Real-Time Imaging of Brain Tumor for Image-Guided Surgery.

Abstract: The completion of surgical resection is a key prognostic factor in brain tumor treatment. This requires surgeons to identify residual tumors in theater as well as to margin the proximity of the tumor to adjacent normal tissue. Subjective assessments, such as texture palpation or visual tissue differences, are commonly used by oncology surgeons during resection to differentiate cancer lesions from normal tissue, which can potentially result in either an incomplete tumor resection, or accidental removal of normal tissue. Moreover, malignant brain tumors are even more difficult to distinguish from normal brain tissue, and resecting noncancerous tissue may create neurological defects after surgery. To optimize the resection margin in brain tumors, a variety of intraoperative guidance techniques are developed, such as neuronavigation, magnetic resonance imaging, ultrasound, Raman spectroscopy, and optical fluorescence imaging. When combined with appropriate contrast agents, optical fluorescence imaging can provide the neurosurgeon real-time image guidance to improve resection completeness and to decrease surgical complications.

Left prefrontal neuronavigated electrode localization in tDCS: 10-20 EEG system versus MRI-guided neuronavigation.

Abstract: Transcranial direct current stimulation (tDCS) involves positioning two electrodes at specifically targeted locations on the human scalp. In neuropsychiatric research, the anode is often placed over the left dorsolateral prefrontal cortex (DLPFC), while the cathode is positioned over a contralateral cephalic region above the eye, referred-to as the supraorbital region. Although the 10–20 EEG system is frequently used to locate the DLPFC, due to inter-subject brain variability, this method may lack accuracy. Therefore, we compared in forty participants left DLPFC-localization via the 10–20 EEG system to MRI-guided neuronavigation. In one participant, with individual electrode positions in close proximity to the mean electrode position across subjects, we also investigated whether distinct electrode localizations were associated with different tDCS-induced electrical field distributions. Furthermore, we aimed to examine which neural region is targeted when placing the reference-electrode on the right supraorbital region. Compared to the 10–20 EEG system, MRI-guided neuronavigation localizes the DLPFC-targeting anode more latero-posteriorly, targeting the middle prefrontal gyrus. tDCS-induced electric fields (n = 1) suggest that both localization methods induce significantly different electric fields in distinct brain regions. Considering the frequent application of tDCS as a neuropsychiatric treatment, an evaluation and direct comparison of the clinical efficacy of targeting methods is warranted.

High-Frequency Neuronavigated rTMS in Auditory Verbal Hallucinations: A Pilot Double-Blind Controlled Study in Patients With Schizophrenia.

Abstract: Introduction: Despite extensive testing, the efficacy of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) of temporo-parietal targets for the treatment of auditory verbal hallucinations (AVH) in patients with schizophrenia is still controversial, but promising results have been reported with both high-frequency and neuronavigated rTMS. Here, we report a double-blind sham-controlled study to assess the efficacy of high-frequency (20 Hz) rTMS applied over a precise anatomical site in the left temporal region using neuronavigation. Methods: Fifty-nine of 74 randomized patients with schizophrenia or schizoaffective disorders (DSM-IV R) were treated with rTMS or sham treatment and fully evaluated over 4 weeks. The rTMS target was determined by morphological MRI at the crossing between the projection of the ascending branch of the left lateral sulcus and the superior temporal sulcus (STS). Results: The primary outcome was response to treatment, defined as a 30% decrease of the Auditory Hallucinations Rating Scale (AHRS) frequency item, observed at 2 successive evaluations. While there was no difference in primary outcome between the treatment groups, the percentages of patients showing a decrease of more than 30% of AHRS score (secondary outcome) did differ between the active (34.6%) and sham groups (9.1%) (P = .016) at day 14. Discussion: This controlled study reports negative results on the primary outcome but demonstrates a transient effect of 20 Hz rTMS guided by neuronavigation and targeted on an accurate anatomical site for the treatment of AVHs in schizophrenia patients.

A review and comparison of three neuronavigation systems for minimally invasive intracerebral hemorrhage evacuation.

Abstract: Advances in stereotactic navigation technology have helped to improve the ease, reliability, and workflow of neurosurgical intraoperative navigation. These advances have also allowed novel, minimally invasive neurosurgical techniques to emerge. Minimally invasive techniques for intracerebral hemorrhage (ICH) evacuation, including endoscopic evacuation and passive catheter drainage, are notable examples, and as these gain support in the literature and their use expands, stereotactic navigation will take on an increasingly important and central role. Each neurosurgical navigation system has unique characteristics. Operators may find that certain aspects are more important than others, depending on the environment in which the evacuation is performed and operator preferences. This review will describe the characteristics of three popular stereotactic neuronavigation systems and compare their advantages and disadvantages as they relate to minimally invasive ICH evacuation.

Intra-Operative Ultrasound: Tips and Tricks for Making the Most in Neurosurgery.

Abstract: Purpose Advances in intraoperative imaging and neuronavigation techniques have positively affected glioma surgery. The desire to reduce brain-shift-related problems while achieving the real-time identification of lesions and residual and anatomical relationships has strongly supported the introduction of intraoperative ultrasound (ioUS) in neuro-oncological surgery. This paper presents tips based on our experience with ioUS in neurosurgery. Methods We retrospectively analyzed 264 patients who underwent high-grade glioma (HGG) resection at the University of Turin and 60 patients who were treated at the University of Rome. Results The main issues are the correct choice of the probe and how to evaluate the anatomy to understand how the information from the three common US planes (axial, sagittal and coronal plane) can be used in each case. It is also important to correctly identify anatomical structures in ioUS imaging. In a normal brain, the sulci, sickle, tentorium, choroid plexus, ependyma and the walls of the vessels are all hyperechoic. In addition, some structures are hypoechoic with a homogeneous acoustic gradient: ventricles, cysts and everything that contains liquor. Tumors are usually hyperechoic in ioUS because of their higher cellularity. Conversely, acute edema that contains fluid is hypoechoic, while chronic edema is hyperechoic. Conclusions IoUS is a real-time, accurate and inexpensive imaging method. The difficulties of interpretation can be overcome by experience in US imaging and a better understanding of the interaction between navigation and imaging fusion techniques. Training on a large number of cases is important for the correct assessment of ioUS information to obtain valuable, real-time information during HGG surgery.

Brain biopsy performed with the RONNA G3 system: a case study on using a novel robotic navigation device for stereotactic neurosurgery.

Abstract: BACKGROUND Robotic neuronavigation is becoming an important tool for neurosurgeons. We present a case study of a frameless stereotactic biopsy guided by the RONNA G3 robotic neuronavigation system. METHODS A 45 year-old patient with a history of vertigo, nausea and vomiting was diagnosed with multiple periventricular lesions. Neurological status was unremarkable. A frameless robotic biopsy of a brain lesion was performed. RESULTS Three tissue samples were obtained. There were no intraoperative or postoperative complications. Histological analysis showed a B-cell lymphoma. After merging the preoperative CT scan with the postoperative MRI and CT scans, the measured error between the planned and the postoperatively measured entry point was 2.24 mm and the measured error between the planned and postoperatively measured target point was 2.33 mm. CONCLUSIONS The RONNA G3 robotic system was used to navigate a Sedan brain biopsy needle to take tissue samples and could be a safe and precise tool for brain biopsy.

Fluorescein-Guided Surgery for Pediatric Brainstem Gliomas: Preliminary Study and Technical Notes.

Abstract: Introduction Brainstem gliomas (BsG) account for 10 to 15% of pediatric brain tumors. Surgery is the preferred treatment for focal and exophytic lesions. Sodium fluorescein has been proven safe and effective in resection of malignant brain tumors. Objective The objective was to o analyze the safety and effectiveness of this approach, to evaluate intraoperative fluorescein imaging, and to measure the safety of chosen dose for pediatric patients. Methods Twelve cases were enrolled between March 2014 and September 2016 in Beijing Tiantan Hospital. All of the patients received 2.5 mg/kg of sodium fluorescein before opening the dura; the intraoperative fluorescence enhancement was observed, and the degree of satisfaction and consistency with the neuronavigation were evaluated. Results With a mean age of 7.5 years, there were eight cases located within the pontine, three in the medullary oblongata, and one in the tectal plate. Histological results were astrocytoma, glioblastoma, oligodendroglioma, and pilocytic astrocytoma. Under the fluorescein module of the microscope, the tumors were recognizable enough to help surgeons to discriminate the lesion from non-fluorescent tissue, with a consistency of 83% with the neuronavigation. Total removal was accomplished in nine cases, while the mean percentage of resection of the other cases was 93.7%. The Karnofsky performance score (KPS) showed no significant differences between pre-operation and discharge, but there was a difference between pre-operation and 6-month follow-up. Conclusion The fluorescein-guided surgery is useful for demarcating the tumor margin and works well with other navigation and monitoring devices. A safe dose of sodium fluorescein (2.5 mg/kg) was proven effective for children.

Navigated 3D–ultrasound versus conventional neuronavigation during awake resections of eloquent low-grade gliomas: a comparative study at a single institution

Abstract: The data showing usefulness of navigated 3D–ultrasound (3DUS) during awake resections of eloquent gliomas are sparse. Results of surgeries performed using 3DUS were never compared to procedures guided by standard neuronavigation. The aim of this work is to assess the effectiveness of 3DUS during awake resections of eloquent low-grade gliomas (LGGs) by comparing surgical results of two series of patients operated on using conventional neuronavigation and using 3DUS. To our knowledge, a similar study is lacking in the literature. During a 4-year period (September 2006 to August 2010) 21 awake resections of LGGs guided by neuronavigation (series 1, S1) were consecutively performed in Department of Neurosurgery in Bratislava. During another 4-year period (August 2010 to July 2014) 28 awake resections of LGGs guided by 3DUS (series 2, S2) were consecutively conducted. In both patients series, the eloquent cortical and subcortical structures were intraoperatively detected by direct electrical stimulation. Extent of tumor resection (EOR) and functional outcome in both series were compared. EOR was significantly greater (p = 0.022) in S2 (median = 93.25%; mean = 86.79%), as compared to S1 (median 87.1%; mean = 75.85%). One permanent minor deficit in S1 and 2 minor deficits in S2 occurred, the difference was not significant (p = 0.999). Our work represents the first study comparing results of surgeries guided by 3DUS versus conventional navigation. The extent of awake resections of eloquent LGG guided by 3DUS was greater comparing to awake resections guided by standard neuronavigation; use of 3DUS had no impact on the number of new permanent deficits.

Robotic-Assisted and Image-Guided MRI-Compatible Stereoelectroencephalography.

Abstract: Background Stereoelectroencephalography has been in regular use at the Montreal Neurological Institute since 1972. The technique has been in constant evolution to incorporate advances in materials, imaging, and robotics technology. MRI-compatible electrodes were introduced in 2007 and robotics in 2011. Here we report on the technique, safety, and advantages of our current method of stereoelectroencephalography implantation. Methods We retrospectively reviewed all patients who underwent stereoelectroencephalography by the senior author. Technical, clinical, and radiological complications, and postimplantation outcomes were analyzed. Only patients implanted with MRI-compatible electrodes were included to review MRI abnormalities with electrodes in situ. Results A total of 53 patients were implanted with 550 electrodes (average=10.4 per patient), for an average duration of 14.6 days. There was no mortality, infection, or new neurologic deficit. Two patients had a superficial screw plunge without clinical consequence. Four patients demonstrated asymptomatic MRI abnormalities (7.54% per patient, or 0.72% per electrode). MRI with electrodes in situ was used for neuronavigation in all 29 who underwent resection and yielded a histopathological diagnosis of focal cortical dysplasia in 15 MRI-negative patients. Conclusions The technique of stereoelectroencephalography described here was associated with no clinical morbidity although not without technical complications or radiologic (MRI) abnormalities. We should therefore remain vigilant in refining the technique and minimizing the number of electrodes required to answer a well-developed hypothesis regarding the epileptogenic zone. The use of MRI-compatible electrodes allowed neuronavigation using the images with the electrodes in situ, which was useful to tailor the eventual definitive resection and in localizing MRI-negative lesions.

3D printing and intraoperative neuronavigation tailoring for skull base reconstruction after extended endoscopic endonasal surgery: proof of concept

Abstract: OBJECTIVEEndoscopic endonasal approaches are increasingly performed for the surgical treatment of multiple skull base pathologies. Preventing postoperative CSF leaks remains a major challenge, particularly in extended approaches. In this study, the authors assessed the potential use of modern multimaterial 3D printing and neuronavigation to help model these extended defects and develop specifically tailored prostheses for reconstructive purposes.METHODSExtended endoscopic endonasal skull base approaches were performed on 3 human cadaveric heads. Preprocedure and intraprocedure CT scans were completed and were used to segment and design extended and tailored skull base models. Multimaterial models with different core/edge interfaces were 3D printed for implantation trials. A novel application of the intraoperative landmark acquisition method was used to transfer the navigation, helping to tailor the extended models.RESULTSProstheses were created based on preoperative and intraoperative CT scans. The naviga...

Tumor Volume Assessment in Low-Grade Gliomas: A Comparison of Preoperative Magnetic Resonance Imaging to Coregistered Intraoperative 3-Dimensional Ultrasound Recordings.

Abstract: Background Image guidance based on magnetic resonance imaging (MRI) and/or ultrasound (US) is widely used to aid decision making in glioma surgery, but tumor delineation based on these 2 modalities does not always correspond. Objective To analyze volumes of diffuse low-grade gliomas (LGGs) based on preoperative 3-D FLAIR MRIs compared to intraoperative 3-D US image recordings to quantitatively assess potential discrepancies between the 2 imaging modalities. Methods Twenty-three patients with supratentorial WHO grade II gliomas undergoing primary surgery guided by neuronavigation based on preoperative FLAIR MRI and navigated 3-D US were included. Manual volume segmentation was performed twice in 3-D Slicer version 4.0.0 to assess intrarater variabilities and compare modalities with regard to tumor volume. Factors possibly related to correspondence between MRI and US were also explored. Results In 20 out of 23 patients (87%), the LGG tumor volume segmented from intraoperative US data was smaller than the tumor volume segmented from the preoperative 3-D FLAIR MRI. The median difference between MRI and US volumes was 7.4 mL (range: -4.9-58.7 mL, P Conclusion The tumor volumes of LGGs segmented from intraoperative US images were most often smaller than the tumor volumes segmented from preoperative MRIs. There was a much better match between the 2 modalities in astrocytomas.

Transsphenoidal surgery: accuracy of an image-guided neuronavigation system to approach the pituitary fossa (sella turcica).

Abstract: OBJECTIVE To determine the accuracy of locating the pituitary fossa with the Brainsight neuronavigation system by determining the mean target error of the rostral (tuberculum sellae) and caudal (dorsum sellae) margins of the pituitary fossa. STUDY DESIGN Experimental cadaveric study. ANIMALS Ten canine cadavers. METHODS Computed tomography (CT) and MRI were performed on each cadaver with fiducials in place. Images were saved to the neuronavigation computer and used to plan the drilling approach. The cadavers were placed in the surgical head clamp of the Brainsight system and positioned for a transsphenoidal approach. On the basis of the planning, 2 localization points were drilled, 1 each at the rostral and caudal margins of the pituitary fossa, and CT was repeated. Error was assessed from the difference in millimeters between the targets identified during Brainsight planning and the actual location of the 2 points drilled on each cadaver skull as identified by postdrilling CT. RESULTS The rostral and caudal margins of the pituitary fossa provided 2 target points per cadaver. The median target error (interquartile range) for all target sites (n = 20) was 3.533 mm (range, 2.013-4.745). CONCLUSION This stereotactic system allowed the surgeon to locate the rostral and caudal margins of the pituitary fossa with clinically acceptable accuracy and confidence. CLINICAL SIGNIFICANCE Using the Brainsight neuronavigation system for localization during transsphenoidal hypophysectomy may decrease morbidity and surgical time.

Mixed-Reality Guidance for Brain Stimulation Treatment of Depression

Abstract: Depression affects more than 16 million American adults and more than half do not respond to medication. Transcranial magnetic stimulation (TMS) is an important anti-depressant treatment that targets specific brain circuits responsible for mood and behavior. TMS efficacy and risk is strongly linked to correct TMS coil placement and can be significantly improved by accurate neuronavigation. In this paper, we present tools for the development of a novel mixed reality neuronavigation setup that allows the TMS operator to view the patient's brain anatomy directly overlaid on the head. This is performed by integrating patient tracking and visualization of brain magnetic resonance imaging (MRI) to provide a streamlined visualization of the patient's anatomy in a single immersive environment.

A novel re-attachable stereotactic frame for MRI-guided neuronavigation and its validation in a large animal and human cadaver model.

Abstract: OBJECTIVE: Stereotactic frame systems are the gold-standard for stereotactic surgeries, such as implantation of deep brain stimulation (DBS) devices for treatment of medically resistant neurologic and psychiatric disorders. However, frame-based systems require that the patient is awake with a stereotactic frame affixed to their head for the duration of the surgical planning and implantation of the DBS electrodes. While frameless systems are increasingly available, a reusable re-attachable frame system provides unique benefits. As such, we created a novel reusable MRI-compatible stereotactic frame system that maintains clinical accuracy through the detachment and reattachment of its stereotactic devices used for MRI-guided neuronavigation. APPROACH: We designed a reusable arc-centered frame system that includes MRI-compatible anchoring skull screws for detachment and re-attachment of its stereotactic devices. We validated the stability and accuracy of our system through phantom, in vivo mock-human porcine DBS-model and human cadaver testing. MAIN RESULTS: Phantom testing achieved a root mean square error (RMSE) of 0.94 ± 0.23 mm between the ground truth and the frame-targeted coordinates; and achieved an RMSE of 1.11 ± 0.40 mm and 1.33 ± 0.38 mm between the ground truth and the CT- and MRI-targeted coordinates, respectively. In vivo and cadaver testing achieved a combined 3D Euclidean localization error of 1.85 ± 0.36 mm (p < 0.03) between the pre-operative MRI-guided placement and the post-operative CT-guided confirmation of the DBS electrode. SIGNIFICANCE: Our system demonstrated consistent clinical accuracy that is comparable to conventional frame and frameless stereotactic systems. Our frame system is the first to demonstrate accurate relocation of stereotactic frame devices during in vivo MRI-guided DBS surgical procedures. As such, this reusable and re-attachable MRI-compatible system is expected to enable more complex, chronic neuromodulation experiments, and lead to a clinically available re-attachable frame that is expected to decrease patient discomfort and costs of DBS surgery.

Stereotactic Cryodestruction of Gliomas.

Abstract: Surgical resection of gliomas affecting functionally important brain structures is associated with high risk of permanent postoperative neurological deficit and deterioration of the patient's quality of life The availability of modern neuroimaging and neuronavigation permits the application of minimally invasive stereotactic cryodestruction of the tumor in such cases The authors used this treatment in 88 patients with supratentorial gliomas of various WHO histopathological grades not suitable for microsurgical resection Postoperative mortality (11%) and rate of surgical complications (114%) were comparable to reported results of stereotactic brain tumor biopsy, whereas the rate of neurological morbidity (42%) was comparable to outcome after resection of gliomas within eloquent brain areas The majority of complications were temporary, and permanent deterioration of neurological function was noted in 8% of cases only The median survival after treatment in patients with glioblastoma and anaplastic astrocytoma was 124 and 469 months, respectively, and was not reached in cases of diffuse astrocytoma, which compared favorably both with historical controls and literature data Therefore, it seems reasonable to consider stereotactic cryodestruction in multimodality management strategies of "unresectable" intracranial gliomas, and further studies directed at evaluation of its efficacy are definitely needed

Microsurgical Resection of a Large Intraventricular Trigonal Tumor: 3-Dimensional Operative Video.

Abstract: A 62-yr-old woman presented with incidentally detected left trigonal mass by magnetic resonance imaging (MRI) performed during workup for left-sided hearing loss and vertigo of 5-yr duration. Due to persistent dizziness, headache, and progressive enlargement of the tumor in follow-up scans, operation was planned. Because the tumor extended superiorly, a superior parietal lobule approach was selected.She underwent a left parietal craniotomy. A strip electrode was used to localize the motor and sensory regions, and neuronavigation was used to confirm the entry site. A small transsulcal corticotomy was performed posterior to a large cortical vein. The tumor was pinkish in color with a well-defined capsule. It was centrally debulked by using curettes, pituitary forceps, and the ultrasonic aspirator. Tumoral blood supply from the choroid plexus and the posterior choroidal vessels were cauterized and divided. Additional blood supply coming from the anterior choroidal vessels was also found and cauterized. After circumferential dissection of the tumor capsule, the tumor was removed completely. The pathology indicated WHO Grade I meningioma. The patient had mild expressive and receptive aphasia postoperatively, but improved progressively. The postoperative MRI showed total resection with no evidence of brain injury. At 3-mo follow-up, the speech was normal; she was independent for all daily activities, but had not yet returned to work (Karnofsky score 80).This 3-D video shows the technical nuances of microsurgical resection of an intraventricular tumor through a narrow brain corridor.Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Electromagnetic neuronavigation for the percutaneous treatment of trigeminal neuralgia with balloon compression: technical note and cadaveric validation study

Abstract: Several techniques have been described for the percutaneous treatment of trigeminal neuralgia; however, each has significant drawbacks. We propose a new technique for percutaneous balloon compression of the trigeminal ganglion and distal trigeminal nerve using electromagnetic (EM) neuronavigation. The procedure was performed in 17 consecutive patients with trigeminal neuralgia. Patients were then followed up with telephone interview. We also performed a cadaveric validation study to further investigate the accuracy of the technique using dye. Excellent clinical outcomes were achieved with a reduction in the median pain score from 10 out of 10 to 0 out of 10 following the procedure. The cadaveric study also demonstrated a high rate of foramen ovale cannulation. EM-based targeting of the foramen ovale and balloon inflation within Meckel’s cave is a quick, reproducible and straightforward technique for the percutaneous treatment of trigeminal neuralgia.

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas.

Abstract: Endoscopic endonasal trans-sphenoidal surgery has become the gold standard for the surgical treatment of pituitary adenomas and many other pituitary lesions. Refinements in surgical techniques, technological advancements, and incorporation of neuronavigation have rendered this surgery minimally invasive. The complication rates of this surgery are very low while excellent results are consistently obtained through this approach. This paper focuses on the step-by-step surgical approach to pituitary adenomas, which is based on personal experience, and details the results obtained with this minimally invasive surgery.

Development and validation of a 3D-printed neuronavigation headset for therapeutic brain stimulation.

Abstract: BACKGROUND Accurate neuronavigation is essential for optimal outcomes in therapeutic brain stimulation. MRI-guided neuronavigation, the current gold standard, requires access to MRI and frameless stereotaxic equipment, which is not available in all settings. Scalp-based heuristics depend on operator skill, with variable reproducibility across operators and sessions. An intermediate solution would offer superior reproducibility and ease-of-use to scalp measurements, without requiring MRI and frameless stereotaxy. OBJECTIVE We present and assess a novel neuronavigation method using commercially-available, inexpensive 3D head scanning, computer-aided design, and 3D-printing tools to fabricate form-fitted headsets for individuals that hold a stimulator, such as an rTMS coil, in the desired position over the scalp. METHODS 20 individuals underwent scanning for fabrication of individualized headsets designed for rTMS of the left dorsolateral prefrontal cortex (DLPFC). An experienced operator then performed three trials per participant of three neuronavigation methods: MRI-guided, scalp-measurement (BeamF3 method), and headset placement, and marked the sites obtained. Accuracy (versus MRI-guidance) and reproducibility were measured for each trial of each method. RESULTS Within-subject accuracy (against a gold-standard centroid of three MRI-guided localizations) for MRI-guided, scalp-measurement, and headset methods was 3.7 ± 1.6 mm, 14.8 ± 7.1 mm, and 9.7 ± 5.2 mm respectively, with headsets significantly more accurate (M = 5.1, p = 0.008) than scalp-measurement methods. Within-subject reproducibility (against the centroid of 3 localizations in the same modality) was 3.7 ± 1.6 mm (MRI), 4.2 ± 1.4 (scalp-measurement), and 1.4 ± 0.7 mm (headset), with headsets achieving significantly better reproducibility than either other method (p < 0.0001). CONCLUSIONS 3D-printed headsets may offer good accuracy, superior reproducibility and greater ease-of-use for stimulator placement over DLPFC, in settings where MRI-guidance is impractical.

Transcranial and Epidural Approach for Spontaneous Cerebrospinal Fluid Leakage Due to Meningoencephalocele of the Lateral Sphenoid Sinus.

Abstract: We experienced a case of sphenoid sinus type meningoencephalocele manifesting as severe cerebrospinal fluid (CSF) rhinorrhea. A 35-year-old man became aware of serous nasal discharge 1 year previously, which had gradually worsened. The nasal discharge was diagnosed as CSF rhinorrhea. Head computed tomography (CT) showed several small depressions in the bone of the left middle cranial fossa, and the largest depression extended through the bone to the lateral sphenoid sinus. Head magnetic resonance imaging revealed that the meningoencephalocele projected to the lateral sphenoid sinus, through this small bone defect of the middle cranial fossa. We performed a combined craniotomy and epidural approach without intradural procedures using neuronavigation. Multiple meningoencephaloceles protruded into small depressions in the middle skull base. The small protrusions not passing through the sphenoid sinus were coagulated. The largest protrusion causing the CSF leakage was identified by neuronavigation. This meningoencephalocele was cut. Both the dural and bone sides were closed with double layers to prevent CSF leakage. The CSF rhinorrhea completely stopped after the surgery. In our case, identification of the leak site was easy with neuronavigation based on bone window CT. The epidural approach also has significant advantages with double layer closure, including both the dural and bone sides. If the site of CSF leakage is outside the foramen rotundum (as with the most common type of lateral sphenoid sinus meningoencephalocele), we recommend the epidural approach using neuronavigation for surgical treatment.