Manual Instruments as an Alternative to Drilling for Bony Exposure in Skull Base Surgery: Concept and Technique.

Background Drilling in neurosurgery is an integral part of surgical exposure, especially in skull base approaches and craniovertebral junction (CVJ) surgeries. Most of such drillings are done in close proximity to the neurovascular structures in skull base surgeries and cervical-medullary junction or facet/pedicle in CVJ surgeries. Reluctance to drilling among young neurosurgeons is due to less hands-on experience during training and also, in the early part of the career, due to fear of injury to neurovascular structures. Methods Five commonest bone removals for skull base region and CVJ surgeries that can be safely done using manual instruments were identified based on experiences of senior authors. The authors highlight key technical nuances to widen surgical corridors using manual instruments safely for skull base surgical approaches. Results Basic neuroanatomical concepts and basic physics help in using manual instruments safely for bone removals in various skull base surgical approaches. Conclusions Manual instruments may be used for bone removals in selected skull base surgical approaches, which help young neurosurgeons to perform these surgeries in limited-resource settings.

Primary Diffuse Leptomeningeal Melanomatosis in an Indian Child With Review of Literature.

BACKGROUND: Primary diffuse leptomeningeal melanomatosis (PDLM) is an extremely rare, aggressive malignant neoplasia of the central nervous system. We report the first case of pediatric PDLM from India. METHODS: A review of literature was done to describe the 15 pediatric cases reported so far. RESULTS: A 12-year-old male child presented with fever, vomiting, and headache for 2 months. Cerebrospinal fluid examination was normal. An MRI of the brain revealed hydrocephalus, for which antitubercular therapy was started and external ventricular drainage followed by ventriculoperitoneal shunt was done. Repeat MRI revealed a suprasellar lesion, nodular enhancement of cranial nerves along with dural enhancement of spinal cord with arachnoiditis, and long-segment myelomalacia. Repeat cerebrospinal fluid examination was negative for malignant cells. During biopsy, blackish dura with diffuse blackish deposits in ventricle were noted. Histopathological examination revealed tumor cells with intracytoplasmic coarse brown pigment melanoma, frequent mitotic figures, and immunohistochemistry testing was positive for human melanoma black-45 and MelanA, suggestive of PDLM. He expired 4 months after the diagnosis. CONCLUSION: Diagnosing PDLM can be daunting in light of its slow but malignant progression mimicking TBM leading to improper management. However, the absence of any supportive microbiological evidence and failure to respond to the standard antitubercular therapy with subsequent progression of the symptoms should prompt the need for finding an alternative diagnosis. A targeted molecular diagnosis and precision medicine may provide a favorable outcome in children with PDLM.

Skull base dural reflection models: tool for teaching neuroanatomy at resource-scarce centers.

Skull base dural reflections are complex, and along with various ligaments joining sutures of the skull base, are related to most important vessels like internal carotid arteries (ICA), vertebral arteries, jugular veins, cavernous sinus, and cranial nerves which make surgical approaches difficult and need thorough knowledge and anatomy for a safe dissection and satisfactory patient outcomes. Cadaver dissection is much more important for the training of skull base anatomy in comparison to any other subspecialty of neurosurgery; however, such facilities are not available at most of the training institutes, more so in low- and middle-income countries (LMICs). A glue gun (100-Watt glue gun, ApTech Deals, Delhi, India) was used to spread glue over the superior surface of the bone of the skull base over desired area (anterior, middle, or lateral skull base). Once glue was spread over the desired surface uniformly, it was cooled under running tap water and the glue layer was separated from the skull base. Various neurovascular impressions were colored for ease of depiction and teaching. Visual neuroanatomy of the inferior surface of dural reflections of the skull base is important for understanding neurovascular orientations of various structures entering or exiting the skull base. It was readily available, reproducible, and simple for teaching neuroanatomy to the trainees of neurosurgery. Skull base dural reflections made up of glue are an inexpensive, reproducible item that may be used for teaching neuroanatomy. It may be useful for trainees and young neurosurgeons, especially at resource-scarce healthcare facilities.

Simulation of surgery for supratentorial gliomas in virtual reality using a 3D volume rendering technique: a poor man's neuronavigation.

OBJECTIVE: Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described. METHODS: The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows. RESULTS: The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs). CONCLUSIONS: Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.

Congenital Skull Anomaly with Multiple Brain Stones and Symptomatic Meningioma of Medial Sphenoid Wing.

Intracranial calcifications are not uncommon and are mostly seen with intracerebral hematomas, tuberculomas, and brain tumors. These lesions may be intra- or extra-axial and occasionally pose challenge in the diagnosis. We report a case of multiple intracranial extra-axial calcifications with congenital skull anomaly and multiple meningiomas. Authors could not find similar case reported in the literature and present their findings and discuss relevant literature.