Optochiasmatic Cavernomas: Updated systematic review and proposal of a novel classification with surgical approaches.

Cavernomas are histologically benign vascular malformations found at different sites in the brain. A rare site for such cavernomas, however, is the anterior optic pathway, comprising the optic nerve, chiasma, and optic tract-called optochiasmatic cavernomas (OCC). These lesions usually present with sudden onset or progressive vision loss, headache, and features mimicking pituitary apoplexy. In this paper, we describe a case of OCC operated at our center. We carry out an updated review of literature depicting cases of OCC, their clinical presentation, management, and postoperative complications. We also propose a novel classification system based on lesion location and further analyze these cavernoma types with respect to the surgical approach used and visual outcome. A 30-year-old lady had presented with a 3-week history of progressive bilateral vision loss and headache. Based on imaging, she was suspected to have a cavernous angioma of the chiasma and left optic tract. Due to progressive vision deterioration, the lesion was surgically excised using pterional craniotomy. Postoperatively, her visual symptoms improved, but she developed diabetes insipidus. Clinical and radiological follow-up has been done for 18 months after surgery. A total of 81 cases have been described in the literature, including the present case. Chiasmal apoplexy is the most common presentation. Surgical excision is the standard of care. Our analysis based on lesion location shows the most appropriate surgical approach to be used for each cavernoma type. Visual outcome correlates with the preoperative visual status. Visual outcome is good in patients presenting with acute chiasmal apoplexy, and when complete surgical excision is performed. The endonasal endoscopic approach was found to provide the best visual outcome. In addition to preoperative visual status, complete surgical excision predicts favorable visual outcomes in OCC. Our proposed classification system guides the appropriate surgical approach required for a particular location of the cavernoma.

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.

Giant skull vault defect in a child caused by Langerhans cell histiocytosis: the "calvaria-eating disease".

Langerhans cell histiocytosis (LCH) is a rare disease of young children that can be difficult to diagnose and treat. Clinical manifestations can sometimes be quite unusual, and bony lesions can reach a large size before treatment is sought. We present a unique case of a 3-year-old male child with a painless giant calvarial defect and cystic swelling. Complete removal of the cyst with curettage of the involved bone margins and cranioplasty was done using bone cement (polymethyl methacrylate, PMMA). However, there was a flare up of the disease due to abnormal inflammatory reaction to PMMA, and cranioplasty bone flap had to be removed. The child did well after PMMA bone flap removal.LCH should be suspected in a male child presenting with a large calvarial defect and no history of trauma. The use of materials, viz., hydroxyapatite, poly-DL-lactide (PDLLA), and PMMA for cranioplasty in LCH, may cause reactivation of the disease process and therefore must be used cautiously in these patients.

Clear Cell Meningioma with Tyrosine Crystals: a Case Report with Review of Literature.

INTRODUCTION OR BACKGROUND: Clear cell meningioma is a rare WHO grade 2 tumour and runs an aggressive course. Tyrosine crystals are very uncommon in meningioma. CASE PRESENTATION: We present a case of a 43-year female with right middle and posterior cranial fossa space occupying lesion (SOL) diagnosed as clear cell meningioma with presence of numerous tyrosine crystals. DISCUSSION AND CONCLUSION: Whether these crystals are incidentally noted or if there is an actual relationship of these crystals with tumour environment must be found as they are seen in many other conditions too.

Setting Up a Department of Neurosurgery in a Government Hospital in an LMIC: Jodhpur, India.

BACKGROUND: The number of government institutes offering affordable super specialty and tertiary healthcare in India has traditionally not been able to keep pace with the growth in population, most of whom are too poor to be able to afford private healthcare services. To meet this mandate, 6 new institutes built on the template of the premier institute of the country-the All India Institute of Medical Sciences, New Delhi-were founded and began operations in 2012. Using the progress of our department as an example, the aim of this report is to outline the principles that were followed to set up the department of neurosurgery. METHODS: The Department of Neurosurgery at All India Institute of Medical Sciences, Jodhpur, began providing services in August 2017. Data related to the inception and development of the department were collected. RESULTS: The department has grown during the past 5 years from 400 outpatients and 79 inpatients in 2017 to 11,144 outpatients and 1624 inpatients in 2022. Only 59 surgeries were performed in 2017 compared with 597 routine and 311 emergency procedures performed in 2022. Currently, the department has 7 faculty members performing all forms of complex skull base, craniovertebral junction, vascular, endovascular, epilepsy, and functional surgeries. A total of 134 studies have been reported in national and international journals, and 8 patents have been granted. CONCLUSIONS: We report the unique experiences of one department that could be useful as a template and as guidelines for the establishment process of a new department.

Evaluation of Utility of Invasive Electroencephalography for Definitive Surgery in Patients with Drug-Resistant Epilepsy: A Systematic Review and Meta-Analysis.

When noninvasive tests are unable to define the epileptogenic zone in patients, intracranial electroencephalography (iEEG) is a method of localizing the epileptogenic zone. Compared with noninvasive evaluations, it offers more precise information about patterns of epileptiform activity, which results in useful diagnostic information that supports surgical decision-making. The primary aim of the present study was to assess the utility of iEEG for definitive surgery for patients with drug-resistant epilepsy. Online databases such as PubMed, Medline, Embase, Scopus, Cochrane Library, Web of Science, and IEEE Xplore were searched for MeSH terms and free-text keywords. The ROBINS I (risk of bias in non-randomized studies - of interventions) critical appraisal tool was used for quality assessment. The prevalence from different studies was pooled together using the inverse variance heterogeneity method. Egger's regression analysis and funnel plot were used to evaluate publication bias. The systematic review included 18 studies, and the meta-analysis included 10 studies to estimate the prevalence of seizure freedom (Engel class I) in patients undergoing surgery after iEEG. A total of 526 patients were included in the meta-analysis. The follow-up period ranged from 1 to 10 years. The overall pooled estimate of the prevalence of seizure freedom (Engel class I) for patients undergoing surgery after iEEG was 53% (95% confidence interval, 44%-62%). The results additionally demonstrated that 12 studies had a moderate risk of bias and 6 had a low risk. Future studies are crucial to enhance our understanding of iEEG to guide patient choices and unravel their implications.

Multiple Symptomatic Spinal Intradural Arachnoid Cysts: A Case Report.

A spinal arachnoid cyst is a rare entity representing only 1 to 3% of spinal canal lesions. Very few of them are reported to be symptomatic. Moreover, occurrence in multiples is even rarer. Extradural type is more common than intradural. In the spine, it is rare in the sacral region. Other common pathologies, such as a dermoid or epidermoid cyst, are often considered at presentation. Even magnetic resonance imaging can miss the diagnosis sometimes. We report a case with symptoms of paraparesis and incontinence at presentation, initially misdiagnosed as a dermoid cyst, later found to be multiple intradural arachnoid cysts located in the sacral region. Spinal arachnoid cysts may cause debilitating symptoms. The disease is completely curable if the detection and classification are early as in our case.

Chondrosarcoma Skull Base: A Case Report.

INTRODUCTION: Chondrosarcomas are primary malignant bone tumor that rarely occurs in the head and neck region. Squash cytology of skull base neoplasm shows atypical chondrocytes and myxoid stroma, which suggests many possibilities like chordoma, chordoid glioma, chordoid meningioma and chondrosarcoma. Isocitrate dehydrogenase gene (IDH) mutations have been reported in 50% to 60% of the head and neck region chondrosarcoma. CASE PRESENTATION: A 37-year-old female came to the outpatient department and complaint of difficulty in walking and swaying to the right side for one year. The radiology was suggestive of right-sided trigeminal schwannoma. However, the squash cytology showed the presence of necrosis, and pink to bluish-coloured myxoid stroma. The tumor cells were pleomorphic and had a hyperchromatic nucleus, hyalinized condensed to granular cytoplasm. The histopathological examination of intraoperative soft tissue showed the presence of cellular lobules of atypical chondrocytes arranged in the myxoid background. The features were of Chondrosarcoma. No parenchymal invasion was found. CONCLUSION: This case report aims to create awareness about a rare tumor, which rarely forms a differential diagnosis for skull base neoplasms. As chondrosarcoma are immunoreactive to IDH1 so this marker can be useful in clinching the diagnosis in conjunction with other immunohistochemical markers in a small biopsy from skull base neoplasms.

Cerebral Ptosis: A Revisit.

Ptosis, unilateral or bilateral, partial or complete, occurring in cases of cerebral ischemic or hemorrhagic stroke, trauma or tumor without involvement of brainstem or oculo-sympathetic mechanism can be termed as cerebral ptosis. Such eyelid dysfunction can occur with hemispheric involvement of either side. It is associated with higher frequency of gaze preference to side of lesion as well as upgaze limitation compared to patients without cerebral ptosis. Here, we present our observations in four such patients with stroke and discuss its evaluation and implications with a brief review of literature.

Handmade models for aneurysm surgery: A useful tool for training.

Background: Aneurysm surgery is considered difficult by young and trainee neurosurgeons. This is due to difficulty in understanding orientation of aneurysm complex (proximal and distal vessels, aneurysm neck, and fundus) in relation to the surrounding structures (skull, brain, vessels, and nerves) after head is rotated, extended, and fixed on the head frame. Virtual three-dimensional (3D) imaging studies and 3D-printed models help young neurosurgeons but are not accessible to most of the centers due to need for resources (human and equipment). Authors used handmade 3D models of aneurysm complex to train young neurosurgeons before and during surgery to make them understand steps to treat it. Methods: RadiAnt DICOM viewer software (2022.1.1, 64-bit, Medixant, Poznan, Poland) was used for acquiring 3D Volume Rendering Technique images to make aneurysm models preoperatively. Twisted 20 Gauze galvanized iron wires were used for making proximal and distal branches and Epoxy Putty (M-seal, Pidilite ® industries, Mumbai, India) was used to make smooth surfaces of the vessels, aneurysm necks, and fundi. Models were used in operating room (OR) before and during surgery to help surgeons and trainees get oriented to the aneurysm complexes. Results: Handmade models, oriented as per patients' head position, were useful to make surgeons and trainees to understand projection of various components of the aneurysm complex in relation to adjacent structures, especially skull base, during both preoperative planning and in OR even before completion of the dissection. Conclusion: Handmade models of aneurysms are inexpensive tool and can help trainee neurosurgeons to plan and execute surgical management of aneurysms.

The Yin and Yang of Operating on a Posterior Fossa Meningioma: The Schmahmann Syndrome.

The cerebellum is classically linked with control of motor function, such as coordination, balance, and regulation of movement. There is an increasing awareness, now, of the non-motor functions of the cerebellum, and the occurrence of behavioral anomalies with cerebellar disorders. We present the first report of Schmahmann syndrome (cerebellar cognitive affective syndrome [CCAS]) occurring secondary to posterior fossa meningioma excision. A 35-year-old lady with a posterior fossa meningioma developed an infarct of the right posterosuperior cerebellar hemisphere and ipsilateral superior vermis, following suboccipital craniotomy and tumor resection. Few days after the surgery, she presented with aggressive and emotional behavior, irrelevant talk, and emotional lability. The CCAS scale was administered, and she scored poorly on almost all parameters. A neuropsychological evaluation was also done. The occurrence of CCAS, posterior fossa syndrome (PFS), and behavioral abnormalities like abnormal pathological laughter/crying provides further clinical evidence of the "affective" functions of the cerebellum, modulated mainly by the posterior lobe and vermis of the cerebellum.

Ultrastructural Changes in Autopsy Tissues of COVID-19 Patients.

INTRODUCTION: The COVID-19 pandemic resulted in substantial morbidity and mortality across the world. The prognosis was found to be poor in patients with co-morbidities such as diabetes, hypertension, interstitial lung disease, etc. Although biochemical studies were done in patient samples, no study has been reported from the Indian subcontinent about ultrastructural changes in the vital organs of COVID-19 patients. The present study was, therefore, conducted to understand the ultrastructural changes in the lung, liver, and brain of the deceased patients. METHODS: The present study was conducted on samples obtained from reverse transcription-polymerase chain reaction (RT-PCR)-positive patients who were admitted to a tertiary care hospital in Western India. Core needle biopsies were done in eight fatal cases of COVID-19. The samples were taken from the lungs, liver, and brain and subjected to light microscopy, immunohistochemistry (IHC), and transmission electron microscopy (TEM). Clinical details and biochemical findings were also collected.  Results: The study participants included seven males and one female. The presenting complaints included fever, breathlessness, and cough. Light microscopy revealed diffuse alveolar damage in the lungs. Further, a positive expression of SARS-CoV-2 nucleocapsid protein was observed in the pulmonary parenchyma of five patients. Also, the TEM microphotograph showed viral particles of size up to 80nm localized in alveolar epithelial cells. However, no viral particles were found in liver or brain samples. In the liver, macrovesicular steatosis and centrizonal congestion with loss of hepatocytes were observed in light microscopy. CONCLUSION:  This is the first study in the Indian population showing the in-situ presence of viral particles in core biopsies from fatal cases of COVID-19. As evident from the results, histology and ultrastructural changes in the lung correlated with the presence of viral particles. The study revealed a positive correlation between the damage in the lungs and the presence of viral particles.

Modified Taylor Retractor in Unilateral Subperiosteal Lumbar Microdiscectomy: A Frugal Alternative to the Tubular Retractor.

OBJECTIVE: To do a comparative surgical outcome and cost-benefit analysis of our simple modified Taylor retractor with both open and tubular techniques in lumbar discectomy. METHODS: We retrospectively divided 52 lumbar disc patients operated by 2 different techniques between January 2019 and June 2020 into 2 groups- group 1 (n = 20): standard open macrodiscectomy (4-5 cm incision); group 2 (n = 32): unilateral translaminar microdiscectomy using our modified Taylor retractor with a small incision (18-20 mm, comparable to the tubular retractor). We compared both groups in terms of surgical outcomes and cost-benefit analysis. In addition, a cost-benefit comparison between our modified Taylor technique and that of the already published tubular microdiscectomy cohort was done. RESULTS: Complete symptom resolution occurred in 85% group 1 and 84.4% group 2 patients, with no difference in complication rates. Mean hospital stay was significantly less in group 2 (1.2 ± 0.37 days) as compared with group 1 (2.4 ± 1.15, P < 0.001). The mean total cost per patient was $2253.17 ± 69.16 in the modified Taylor microdiscectomy group compared with $2495.76 ± 214.85 (P < 0.001) in standard macrodiscectomy. Compared with the previously published tubular microdiscectomy cohort ($3069.91 ± 69.16), the modified Taylor retractor was $816.74 cheaper per patient with similar length of incision, surgical outcome, and hospital stay. CONCLUSIONS: Similar clinical outcomes at decreased costs are obtained using the modified Taylor retractor compared with the tubular retractor. The modified Taylor retractor has a simple design, is user-friendly, and frugal alternative to the tubular retractor system for microscopic discectomy, especially in the resource-constrained countries.

Efficacy of Hyaluronidase in the Mannitol Extravasation Induced Compartment Syndrome-A Case Report and Review of Literature.

Mannitol is one of the indispensable drugs in neurosurgery to manage the raised intracranial pressure. Though considered safe, extravasation of mannitol into the tissues can cause considerable morbidity with the consequent development of compartment syndrome. We report a case of a 50-year-old female who developed forearm compartment syndrome due to mannitol extravasation after undergoing surgery for frontal glioma under general anaesthesia. The severe forearm compartment syndrome could be successfully managed without fasciotomy using hyaluronidase. We describe the pathophysiology, prevention and treatment strategies emphasising the use of hyaluronidase in the management of mannitol extravasation induced compartment syndrome.

Methylmethacrylate Inter-Facetal and Inter-Vertebral Body Spacers for Cranio-Vertebral Junction and Various Spine Surgeries: Technical Note.

STUDY DESIGN: Prospective. PURPOSE: Over past one and half decade, ready-to-use magnetic resonance imaging (MRI) compatible spinal implants have changed the clinical practice and economics of spinal surgery. These are beyond reach of majority of population of developing countries like India due to financial reasons and also availability in remote areas. There is a growing need for a MRI compatible cost-effective spinal implant of proven quality. The authors used bone cement spacers for the said purpose for various level spine surgeries. OVERVIEW OF LITERATURE: Methylmethacrylate, known as bone cement, was used extensively for spinal surgeries from craniovertebral junction to sacrum for augmentation and replacement of various spinal elements. Its biochemical and biomechanical properties were tested for safe clinical use and was a favored material for spinal surgeons. MATERIALS AND METHODS: The authors made molds for making bone cement spacers for various spine levels with the help of silicone material. RESULTS: Sixteen patients (12 males, 4 females with an average age of 31 years) of various spine level surgeries were done where bone cement spacers were used. It included patients of basilar invagination (n = 9), dorsal Pott's disease (n = 1), lumbar (n = 2), and lumbo-sacral spondylolisthesis (n = 1). Spacers could be used without any difficulties and postoperative day 1- and 3-months follow-up computed tomography scan of the patients revealed no change in the dimensions of the spacer and fusion at 3 months of operated levels. CONCLUSION: The authors feel that bone cement spacers may be an effective and low-cost alternative to the existing costly alternatives.

Volume Rendering Technique (VRT) for Planning and Learning Cranio-Vertebral Junction (CVJ) Surgeries: Technical Note.

AIM: To present the application of volume rendering technique (VRT) of computed tomography (CT) scan in cranio-vertebral junction (CVJ) surgeries. MATERIAL AND METHODS: The authors used VRT images of CT scan in patients of congenital CVJ anomalies who were subjected to various surgeries through midline posterior approach. The screw entry points and courses of vertebral arteries were identified in relation to various landmarks on the VRT images, preoperatively and intra-operatively. RESULTS: A total of 15 patients of CVJ anomalies, who underwent surgeries through midline posterior approach, formed the study group. The screw entry points and courses of the vertebral arteries could be effectively identified in the surgical fields. CONCLUSION: We conclude that VRT images are an inexpensive and user friendly tool to identify the screw insertion points in the surgeries of CVJ anomalies. They also help in identifying the course of the vertebral artery in the surgical field. On the whole, their use makes the surgery in this region, safer.

Endoscopic Third Ventriculostomy in Failed Ventriculoperitoneal Shunt in Pediatric Population.

INTRODUCTION: Ventriculoperitoneal (VP) shunt malfunction is common in pediatric age group patients. There is a high complication rate and revision rate of VP shunt. Endoscopic third ventriculostomy (ETV) can alleviate these complications and can act as an effective alternative for the treatment of hydrocephalus in this age group of patients. MATERIALS AND METHODS: The authors retrospectively reviewed the management and outcome of 36 failed VP shunts in pediatric patients for the treatment of hydrocephalus. The surgeries were performed between November 2010 and January 2016 in a tertiary care hospital. The minimal follow-up period was 3 months. We divided the patients into the following age groups: <1 year (eight infants), 1-10 years (18 children), and 10-18 years (10 children). The success of the procedure was determined by age, sex, type of hydrocephalus, and the number of shunt revisions and malfunction before ETV. Children with different age (P = 0.839) and sex group did not show any significant data (P = 0.798). Children with communicating hydrocephalus had a success rate of 52.9% (17 patients), and children with noncommunicating hydrocephalus had a success rate of 84.2% (19 patients). The success rate in children with only one shunt malfunction was 57.1% (21 patients), whereas in 15 children with two or more shunt malfunctions, the success rate of ETV was 86.7%. CONCLUSIONS: The authors conclude that ETV is an effective alternative for the treatment of hydrocephalus in children. Age does not present a contraindication for ETV in failed VP shunt.