White matter tract recovery following medial temporal lobectomy and selective amygdalohippocampectomy for tumor resection via a ROVOT-m port-guided technique: A case report and review of literature

Minimally Invasive Parafascicular Surgical Approach for the Management of a Pediatric Third Ventricular Ependymoma: Case Report and Review of Literature

BACKGROUND

Minimally invasive parafascicular surgery (MIPS) has evolved into a safe alternative to access deep-seated subcortical and intraventricular pathologies. We present a case of a port-mediated resection of a pediatric third ventricular tumor.

CASE DESCRIPTION

The patient is a 7-year-old boy who presented with worsening headache, nausea, vomiting, dizziness, unsteady gait, photophobia, and blind spots with positional changes. Magnetic resonance imaging (MRI) scan revealed a large isointense mass, with areas of hyperintensities suggestive of intratumoral hemorrhage, centered in the posterior segment of the third ventricle with extension into the aqueduct of Sylvius. The superior frontal sulcus was used as an access corridor for the port to the frontal horn of the lateral ventricle en route to the third ventricle. Intraoperative visualization was aided with a 3-dimensional exoscopic system. After cannulation, the tumor was seen within the foramen of Monro and tethered to the thalamostriate vein. The tumor was removed completely, with the exception of small residual attached to the thalamostriate vein, which was left intentionally. A flexible endoscope was placed through the port to verify the absence of residual along the superior wall of the third ventricle. Intraoperative MRI scan confirmed presence of residual, along with normal postoperative changes, including pneumocephalus. Postoperative MRI scan revealed cortical recovery along the sulcal path and resolution of ventriculomegaly.

CONCLUSIONS

The patient improved from baseline, with no remaining visual deficits, headaches, or balance issues. Pathology reported a World Health Organization grade II tanycytic ependymoma. To our knowledge, few cases have reported the utilization of port-based MIPS in pediatric patients.

The Surgical White Matter Chassis: A Practical 3-Dimensional Atlas for Planning Subcortical Surgical Trajectories

BACKGROUND

The imperative role of white matter preservation in improving surgical functional outcomes is now recognized. Understanding the fundamental white matter framework is essential for translating the anatomic and functional literature into practical strategies for surgical planning and neuronavigation.

OBJECTIVE

To present a 3-dimensional (3-D) atlas of the structural and functional scaffolding of human white matter-ie, a "Surgical White Matter Chassis (SWMC)"-that can be used as an organizational tool in designing precise and individualized trajectory-based neurosurgical corridors.

METHODS

Preoperative diffusion tensor imaging magnetic resonance images were obtained prior to each of our last 100 awake subcortical resections, using a clinically available 3.0 Tesla system. Tractography was generated using a semiautomated deterministic global seeding algorithm. Tract data were conceptualized as a 3-D modular chassis based on the 3 major fiber types, organized along median and paramedian planes, with special attention to limbic and neocortical association tracts and their interconnections.

RESULTS

We discuss practical implementation of the SWMC concept, and highlight its use in planning select illustrative cases. Emphasis has been given to developing practical understanding of the arcuate fasciculus, uncinate fasciculus, and vertical rami of the superior longitudinal fasciculus, which are often-neglected fibers in surgical planning.

CONCLUSION

A working knowledge of white matter anatomy, as embodied in the SWMC, is of paramount importance to the planning of parafascicular surgical trajectories, and can serve as a basis for developing reliable safe corridors, or modules, toward the goal of "zero-footprint" transsulcal access to the subcortical space.

Awake Surgical Management of Third Ventricular Tumors: A Preliminary Safety, Feasibility, and Clinical Applications Study

BACKGROUND

Endoscopic and microneurosurgical approaches to third ventricular lesions are commonly performed under general anesthesia.

OBJECTIVE

To report our initial experience with awake transsulcal parafascicular corridor surgery (TPCS) of the third ventricle and its safety, feasibility, and limitations.

METHODS

A total of 12 cases are reviewed: 6 colloid cysts, 2 central neurocytomas, 1 papillary craniopharyngioma, 1 basal ganglia glioblastoma, 1 thalamic glioblastoma, and 1 ependymal cyst. Lesions were approached using TPCS through the superior frontal sulcus. Pre-, intra-, and postoperative neurocognitive (NC) testing were performed on all patients.

RESULTS

No cases required conversion to general anesthesia. Awake anesthesia changed intraoperative management in 4/12 cases with intraoperative cognitive changes that required port re-positioning; 3/4 recovered. Average length of stay (LOS) was 6.1 d ± 6.6. Excluding 3 outliers who had preoperative NC impairment, the average LOS was 2.5 d ± 1.2. Average operative time was 3.00 h ± 0.44. Average awake anesthesia time was 5.05 h ± 0.54. There were no mortalities.

CONCLUSION

This report demonstrated the feasibility and safety of awake third ventricular surgery, and was not limited by pathology, size, or vascularity. The most significant factor impacting LOS was preoperative NC deficit. The most significant risk factor predicting a permanent NC deficit was preoperative 2/3 domain impairment combined with radiologic evidence of invasion of limbic structures – defined as a “NC resilience/reserve” in our surgical algorithm. Larger efficacy studies will be required to demonstrate the validity of the algorithm and impact on long-term cognitive outcomes, as well as generalizability of awake TPCS for third ventricular surgery.

Microsurgical Anatomy of the Vertical Rami of the Superior Longitudinal Fasciculus: An Intraparietal Sulcus Dissection Study

BACKGROUND

A number of vertical prolongations of the superior longitudinal fasciculus, which we refer to as the vertical rami (Vr), arise at the level of the supramarginal gyrus, directed vertically toward the parietal lobe.

OBJECTIVE

To provide the first published complete description of the white matter tracts (WMT) of the Vr, their relationship to the intraparietal and parieto-occipital sulci (IPS-POS complex), and their importance in neurosurgical approaches to the parietal lobe.

METHODS

Subcortical dissections of the Vr and WMT of the IPS were performed. Findings were correlated with a virtual dissection using high-resolution diffusion tensor imaging (DTI) tractography data derived from the Human Connectome Project. Example planning of a transparietal, transsulcal operative corridor is demonstrated using an integrated neuronavigation and optical platform.

RESULTS

The Vr were shown to contain component fibers of the superior longitudinal fasciculus (SLF)-II and SLF-III, with contributions from the middle longitudinal fasciculus merging into the medial bank of the IPS. The anatomic findings correlated well with DTI tractography. The line extending from the lateral extent of the POS to the IPS marks an ideal sulcal entry point that we have termed the IPS-POS Kassam-Monroy (KM) Point, which can be used to permit a safe parafascicular surgical trajectory to the trigone.

CONCLUSION

The Vr are a newly conceptualized group of tracts merging along the banks of the IPS, mediating connectivity between the parietal lobe and dorsal stream/SLF. We suggest a refined surgical trajectory to the ventricular atrium utilizing the posterior third of the IPS, at or posterior to the IPS-POS Point, in order to mitigate risk to the Vr and its considerable potential for postsurgical morbidity.

The Changing Face of Technologically Integrated Neurosurgery: Today's High-Tech Operating Room

Over the last decade, surgical technology in planning, mapping, optics, robotics, devices, and minimally invasive techniques has changed the face of modern neurosurgery. We explore the current advances in clinical technology across all neurosurgical subspecialties, examine how clinical practice is being shaped by this technology, and suggest what the operating room of tomorrow may look like.

Virtual Reality and Simulation in Neurosurgical Training

Recent biotechnological advances, including three-dimensional microscopy and endoscopy, virtual reality, surgical simulation, surgical robotics, and advanced neuroimaging, have continued to mold the surgeon-computer relationship. For developing neurosurgeons, such tools can reduce the learning curve, improve conceptual understanding of complex anatomy, and enhance visuospatial skills. We explore the current and future roles and application of virtual reality and simulation in neurosurgical training.