Stereotactic Biopsy of Brainstem Lesion in Children: Techniques, Efficacy and Safety: Case Review of Single Institutional Experience

Introduction: Stereotactic biopsy of brain stem lesions in children evolved from a controversial background but the current trend seems towards a safe procedure that will yield diagnostic accuracy to guide targeted and individualized treatments. Aims and Objectives: To confirm safety, accuracy and usefulness of biopsy of brain stem lesions using our institutional experience on two index cases that underwent stereotactic procedures. Methodology: A review of two case reports were conducted to expose diagnostic success and procedure-related highpoints. Results: In both cases presented the procedure was uneventful, yielded the desired diagnostic tissue and there were no procedure related complications. Conclusion: Stereotactic biopsy of pediatric brain stem lesion is safe. Tissue sampling was accurate in both cases and served as a prerequisite more targeted oncology referral and potentially individualized treatment.

The Spectrum of Brain Stem Lesions in Children

The objective of this study was to describe the clinicodemographic profiles, management, and outcomes of brain stem lesions in 53 pediatric patients with brain stem lesions. Most of the patients were male, 6 to 10 years of age (8.66 ± 4.69). Out of 53 patients, there were 77.36% brain stem gliomas, 11.32% tuberculomas, 5.66% abscesses, 3.77% cavernomas, and 1.89% schwannomas. With advancement in neuroimaging (e.g., tractography), intraoperative technology (e.g., ultrasound, neurophysiological monitoring, and magnetic resonance imaging), and safe and precise incision for particular lesions, majority of brain stem lesions had improved outcomes (67.92%) with significant reduction in morbidity and mortality (11.32%).

The Conscious Brain

The goal of this article is to review some aspects of brain anatomy and neurophysiology that are important for consciousness, and which hopefully may be of benefit to philosophers investigating the conscious mind. Taking as an initial point of reference the distinction between “the hard problem” and “the weak problems” of consciousness, we shall concentrate on questions pertaining to the second of these. A putative “consciousness system” in the brain will be presented, paying special attention to diffuse projection systems. The “center of gravity” will be brain connectivity, since consciousness must, critically, be dependent on coherent activity and timing. “Detectors” of synchronicity and coincidence, like NMDA receptors, also necessarily play a role here. To be conscious, we do not need an entire brain. While even large hemispherectomies need not unequivocally affect consciousness, far smaller brain-stem lesions may be devastating in this regard. Even so, the recent discovery by Matthew F. Glasser et al. of 180 separate areas in the human brain cortex is intriguing from a teleological perspective, as it is quite unthinkable that any of them could be “redundant.

Where and When to Cut? Fluorescein Guidance for Brain Stem and Spinal Cord Tumor Surgery—Technical Note

BACKGROUND Spinal cord and brain stem lesions require a judicious approach with an optimized trajectory due to a clustering of functions on their surfaces. Intraoperative mapping helps locate function. To confidently locate such lesions, neuronavigation alone lacks the desired accuracy and is of limited use in the spinal cord. OBJECTIVE To evaluate the clinical value of fluoresceins for initial delineation of such critically located lesions. METHODS We evaluated fluorescein guidance in the surgical resection of lesions with blood-brain barrier disruption demonstrating contrast enhancement in magnet resonance imaging in the spinal cord and in the brain stem in 3 different patients. Two patients harbored a diffuse cervical and thoracic spinal cord lesion, respectively. Another patient suffered metastatic lesions in the brain stem and at the floor of the fourth ventricle. Low-dose fluorescein (4 mg/kg body weight) was applied after anesthesia induction and visualized using the Zeiss Pentero 900 Yellow560 filter (Carl Zeiss, Oberkochen, Germany). RESULTS Fluorescein was helpful for locating lesions and for defining the best possible trajectory. During resection, however, we found unspecific propagation of fluorescein within the brain stem up to 6 mm within 3 h after application. As these lesions were otherwise distinguishable from surrounding tissue, monitoring resection was not an issue. CONCLUSION Fluorescein guidance is a feasible tool for defining surgical entry zones when aiming for surgical removal of spinal cord and brain stem lesions. Unselective fluorescein extravasation cautions against using such methodology for monitoring completeness of resection. Providing the right timing, a window of pseudoselectivity could increase fluoresceins’ clinical value in these cases.