Exoscopic resection of atrial intraventricular meningiomas using a navigation-assisted channel-based trans-sulcal approach: Case series and literature review

Primary Stereotactic Radiosurgery Provides Favorable Tumor Control for Intraventricular Meningioma: A Retrospective Analysis

The surgical resection of intraventricular meningiomas (IVMs) remains challenging because of their anatomically deep locations and proximity to vital structures, resulting in non-negligible morbidity and mortality rates. Stereotactic radiosurgery (SRS) is a safe and effective treatment option, providing durable tumor control for benign brain tumors, but its outcomes for IVMs have rarely been reported. Therefore, the goal of the present study was to evaluate the SRS outcomes for IVMs at our institution. This retrospective observational study included 11 patients with 12 IVMs with a median follow-up period of 52 months (range, 3-353 months) treated with SRS using the Leksell Gamma Knife. Nine (75%) tumors were located in the trigone of the lateral ventricle, two (17%) in the body of the lateral ventricle, and one (8%) in the third ventricle. Tumor control was achieved in all cases, and seven (55%) decreased in size. Post-SRS perifocal edema was observed in four (37%; three asymptomatic and one symptomatic but transient) patients, all of which were resolved by the last follow-up. SRS appears to provide safe and excellent tumor control for IVMs. A longer follow-up with a larger number of cases is desired for a more solid conclusion.

Wide Dissection Trans-Sulcal Approach for Resection of Deep Intra-Axial Lesions in Eloquent Brain Areas

Introduction: Resection of intra-axial tumors (IaT) in eloquent brain regions risks major postoperative neurological deficits. Awake craniotomy is often used to navigate these areas; however, some patients are ineligible for awake procedures. The trans-sulcal approach (TScal) was introduced to reduce parenchymal trauma during tumor resection. We report our experiences utilizing TScal for resection of deep IaT located in eloquent areas. Materials and Methods: This is a single-center retrospective analysis of patients who underwent IaT resection in eloquent areas via TScal from January 2013 to April 2021. Seventeen cases were reviewed, and relevant data was collected. Fluorescence-guided surgery with 5-aminolevulinic acid (ALA) and intraoperative ultrasound was performed in some cases. Results: Seventeen patients (10 males, 7 females) averaging 61.2 years-old (range, 21-76) were included in this study. Average length of stay was 4.8 days, and only 2 patients (11.8%) required hospital readmission within 30 days. Gross total resection (GTR) was achieved in 15 patients (88.2%), while subtotal resection occurred in 2 patients (11.8%). Eleven patients (64.7%) reported full resolution of symptoms, 4 patients (23.5%) reported deficit improvement, and 2 patients (11.8%) experienced no change from their preoperative deficits. No patient developed new permanent deficits postoperatively. Discussion: GTR, preoperative deficit reduction, and complications were comparable to awake craniotomy and other TScal studies. Ancillary intraoperative techniques, such as brain mapping, 5-ALA and intraoperative ultrasound, are afforded by TScal to improve resection rates and overall outcomes. Conclusions: TScal can be an option for patients with deep lesions in eloquent areas who are not candidates for awake surgeries.

Exoscope as a Teaching Tool: A Narrative Review of the Literature

Recently, the emergence of the three-dimensional (3D) exoscope has proven to be a viable alternative to the operative microscope (OM) as a novel workhorse of microneurosurgical procedures. Through its current iteration, the 3D exoscope has been demonstrated to be at least equivalent to the operative microscope in terms of surgical outcomes in many settings. With its superior ergonomics and simplicity of use, the 3D exoscope has been shown in multiple studies to be a powerful visualizing tool during surgical procedures. Moreover, the exoscopic systems, through their current iterations and by means of a high-resolution 3D monitor and 3D glasses, have allowed all participants present in the operative room to attain an unprecedented level of intraoperative visualization of anatomical structures and surgical maneuvers which are traditionally available only to the first operator. Although long-term data are still lacking regarding its future as a replacement of the OM, the 3D exoscope has revealed itself as an intense subject of discussion in neurosurgery regarding its implication for surgical education, especially for residents and junior neurosurgeons. This article is a review of the current state of the literature on the role of the exoscope in surgical education, underlining its strength as a learning tool and its potential future implications in terms of surgical education.

The Exoscope in Neurosurgery: An Overview of the Current Literature of Intraoperative Use in Brain and Spine Surgery

Background: Exoscopes are a safe and effective alternative or adjunct to the existing binocular surgical microscope for brain tumor, skull base surgery, aneurysm clipping and both cervical and lumbar complex spine surgery that probably will open a new era in the field of new tools and techniques in neurosurgery. Methods: A Pubmed and Ovid EMBASE search was performed to identify papers that include surgical experiences with the exoscope in neurosurgery. PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) were followed. Results: A total of 86 articles and 1711 cases were included and analyzed in this review. Among 86 papers included in this review 74 (86%) were published in the last 5 years. Out of 1711 surgical procedures, 1534 (89.6%) were performed in the operative room, whereas 177 (10.9%) were performed in the laboratory on cadavers. In more detail, 1251 (72.7%) were reported as brain surgeries, whereas 274 (16%) and 9 (0.5%) were reported as spine and peripheral nerve surgeries, respectively. Considering only the clinical series (40 studies and 1328 patients), the overall surgical complication rate was 2.6% during the use of the exoscope. These patients experienced complication profiles similar to those that underwent the same treatments with the OM. The overall switch incidence rate from exoscope to OM during surgery was 5.8%. Conclusions: The exoscope seems to be a safe alternative compared to an operative microscope for the most common brain and spinal procedures, with several advantages that have been reached, such as an easier simplicity of use and a better 3D vision and magnification of the surgical field. Moreover, it offers the opportunity of better interaction with other members of the surgical staff. All these points set the first step for subsequent and short-term changes in the field of neurosurgery and offer new educational possibilities for young neurosurgery and medical students.

The posterior interhemispheric transparieto-occipital fissure approach to the atrium of the lateral ventricle: a fiber microdissection study with case series

The surgical approach to the atrium of the lateral ventricle remains a challenge because of its deep location and close relationship to important neurovascular structures. We present an alternative and safer approach to lesions of the atrium using a natural pathway through the parieto-occipital fissure. We demonstrate this approach through cadaveric anatomical microdissection and a case series. Five formalin-fixed brain specimens (10 hemispheres) were dissected with the Klingler technique. Transillumination was used to show the trajectory of the approach in cadaveric specimens. Clinical data from five patients who underwent this approach were reviewed. This data included intraoperative ultrasound images, operative images, pre- and postoperative magnetic resonance imaging, MR tractography, and visual field examination. The parieto-occipital fissure is a constant, uninterrupted fissure that can be easily identified in cadavers. Our anatomical dissection study revealed that the atrium of the lateral ventricle can be approached through the parieto-occipital fissure with minor damage to the short association fibers between the precuneus and cuneus, and a few fibers of the forceps major. In our series, five patients underwent total resection of their atrial lesions via the posterior interhemispheric transparieto-occipital fissure. No morbidity or mortality was observed, and the disruption of white matter was minimal, as indicated on postoperative tractography. The postoperative visual fields were normal. The posterior interhemispheric transparieto-occipital fissure approach is an alternative to remove lesions in the atrium of the lateral ventricle, causing the least damage to white matter tracts and preserving visual cortex and optic radiation.

Microsurgical endoportal MRI/US-navigated approach for the resection of large intraventricular tumours: a 20-consecutive patients case series

OBJECTIVES

Deep lesions located in lateral and third ventricles can be accessed thorough interhemispheric transcallosal or transcortical trans-ventricular approaches. Traditional brain retractors are made by 'non-cerebral engineered' spatulas, which do not equally distribute pressure on surrounding structures damaging brain. In this paper, we present a series of 20 intraventricular tumours resected through a MRI/US-navigated microscopic transcortical endoportal approach.

PATIENTS AND METHODS

Between January 2014 and December 2017, 20 patients underwent US-MRI neuronavigated (Esaote^®, Genova, Italy) transcortical endoportal (Vycor^® Viewsite Brain Access System TC Model, Vycor^® Medical Inc., Boca Raton, FL) surgery for intraventricular deep-seated lesions with the intent to reach maximal safe resection.

RESULTS

Gross total removal was achieved in 14 patients (70%). The only prognostic factor that resulted in statistical significance related to surgical radicality from multivariate analysis was white matter infiltration (p = 0.043), regardless of other tumour (dimensions, origin and location inside ventricular system, histopathology) and patient (age, gender, clinical presentation) characteristics. The mean duration of surgery was 225.9 min (± 59). Neither critical events, nor major bleedings, nor intraoperative deaths occurred during surgery. One case of postoperative CSF infection (5%) was registered. Six patients (30%) required permanent CSF drainage system (Ommaya reservoir, VP shunt) in the postoperative period. The mean Functional Independence Measure (FIM) score at last follow-up was 105 (range: 65-124).

CONCLUSIONS

Transcortical transventricular endoportal surgery seems to be a valuable alternative to transcallosal surgery, although further prospective multicentre studies with larger number of patients, evaluation of pre- and post-operative neuropsychological outcomes and achievement of postoperative DTI and f-MRI are needed to confirm our results.

Bur Hole-Based Resections of Intrinsic Brain Tumors with Exoscopic Visualization

BACKGROUND

 The primary goal of brain tumor surgery is maximal safe resection while avoiding iatrogenic injury. As surgical technology increases, it is becoming more possible to resect these lesions using minimally invasive approaches. While keyhole surgeries are being advocated, the lower limit of these approaches is unclear. Bur hole-based approaches may represent a standardized minimally invasive approach. The exoscope may provide increased visualization over standard microscopic visualization, making this approach possible. This approach has yet to be described strictly for intra-axial brain tumors.

MATERIAL AND METHODS

 All patients who underwent a bur hole-based surgery of an intra-axial tumor with exoscopic visualization by the senior author from January 2018 to December 2019 were prospectively identified and patient information and outcomes were collected.

RESULTS

 Fifteen consecutive patients underwent surgical resection of an intrinsic brain tumor using a bur hole-based approach with exoscopic visualization. The average ± standard deviation age was 57.9 ± 24.2 years. The pathology was a metastatic brain tumor in eight patients (53%), low-grade glioma in four patients (27%), and high-grade glioma in three patients (20%). The average percent resection was 100 ± 1%, where 14 (93%) underwent gross total resection. Following surgery, the median (interquartile range) Karnofsky performance scale (KPS) score was 90 (90-90), where 11 (73%) and four patients (27%) had improved and stable KPS, respectively. Zero patients had complications. The average length of stay following surgery was 1.4 ± 0.5 days, where nine patients (60%) were discharged on postoperative day 1.

CONCLUSION

 This study shows that intra-axial tumors can be resected through a bur hole-based approach with exoscopic visualization with extensive resection, minimal morbidity, and early discharge rates.