Stereotactic biopsy for brain lesions: Doing more with less.

Objectives: Stereotactic biopsy (STB) is a potential diagnostic tool considering its minimal invasiveness, high diagnostic yield, and minimal associated complications. Over the years, various frame-based instrument systems and frameless stereotactic biopsy systems have emerged to be employed in clinical use. With this study, we intend to get more by doing less in the form of STB for the patients of doubtful intracranial lesions treated over the past 5 years. We also want to highlight the technique of performing the procedure under scalp block, which can be used as a versatile tool in many clinical scenarios. Stereotactic biopsies may be planned even in rural district-level health facilities. One-time investment to procure instruments and avail existing imaging can lead to establishing definitive diagnoses in many doubtful cases. This will result in lesser cost and early establishment of treatment. Independent risk factors determining the outcome, such as deep-seated lesions, associated edema, and intraoperative hypertension, were studied. Establishing the diagnosis helped in prognosticating the disease, explaining the natural progression of symptoms, and starting adjuvant therapy. This tissue biopsy would also help secure samples for research and molecular analysis. Materials and Methods: Twenty patients underwent STBs at our institution between January 2018 and December 2022. We retrospectively analyzed patient characteristics, tumor pathology, surgical procedures, and outcomes, including the diagnostic value and surgery-related complications. These patients were followed up, and their progression-free and overall survival were analyzed. The need for adjuvant treatment was noted and analyzed. All procedures were performed using Cosman Roberts Wells® stereotactic frame. Pre-procedure magnetic resonance scans were performed at the time of admission. Contrast-enhanced computerized tomography (CT) scan after frame application was performed to identify targets and calculate the coordinates. A post-procedure CT scan was done to confirm the accessibility of the targeted lesion. Results: The most common location of the tumor was a deep-seated thalamic lesion. A definitive diagnosis was established in 19 patients (95%) at the first STB. The diagnoses were glioma in 55% of cases, primary central nervous system lymphoma, tuberculosis, and demyelinating disorders in 10% of each, and a metastatic brain tumor in 1 (5%). The post-operative complications were all transient except in one patient with deterioration of motor weakness. The follow-up was noted, and modes of adjuvant treatment needed in these patients were recorded. Conclusion: Stereotactic biopsy is a useful and effective method for achieving a definitive diagnosis and aiding in treating multifocal or small deep-seated lesions in or around eloquent regions.

Factors predicting seizure outcome after surgical excision of meningioma: SOLID-C guideline for prophylactic AED.

BACKGROUND: Seizures are commonly seen among meningioma patients and may cause impaired quality of life. These patients can be effectively treated with surgery. Still, many patients have persistent seizure episodes after surgery. The factors which are associated with worsening of seizure episodes remain critical in improving the quality of life for such patients. In this study, we aim to analyze the clinical and histopathological factors to predict the post excision seizure-outcome in meningioma and need of antiepileptic prophylaxis for these patients. METHODS: Adult patients who underwent primary resection of meningioma at our institute between 2007 and 2020 were included in the study. Eligibility criteria were as follows: (i) Surgery for newly-diagnosed biopsy proven meningioma, (ii) Presence of pre-operative seizure (iii) A follow-up period ≥ 12 months. RESULTS: Of the 1145 patients in this series, 333 patients were recruited in study. The major determinants of prophylactic anti-epileptic were tumour size (S), Oedema (O), location (L), inclusion body (I), antiepileptic drugs (D) and surgical complication (C). The factors independently associated with poor seizure control after surgical resection were presence of brain parenchyma invasion (p < 0.001), pre-operative use of > 2 antiepileptics (p = 0.016) and presence of intranuclear inclusion bodies (p = 0.001). CONCLUSIONS: The identification and consideration of factors associated with prolonged seizure control after surgery may help us to guide treatment strategies aimed at improving the quality of life for patients with meningiomas. Authors have proposed a SOLID-C guideline to avoid the blanket approach of prophylactic AED in patients undergoing for meningioma resection.

Postoperative Seizure Control in Adult Diffuse Insular Gliomas Presenting with Seizures: A Retrospective Single-Center Experience and Proposal of a Novel Risk Scoring System.

Background: Studies on insular gliomas (IGs) generally focus on the oncological endpoints with a relative scarcity of literature focusing on the seizure outcomes. Objectives: To study the predictors of long-term postoperative seizure control in IG and propose a novel risk scoring system. Methods: Histopathologically proven, newly diagnosed adult IGs (>18 years) operated over a 10-year period were studied for postoperative seizure control as per International League Against Epilepsy (ILAE) grades at 6 weeks and at last follow-up (minimum of 6 months, median 27 months). Logistic regression analysis was performed and regression coefficients with nearest integers were used to build a risk prediction model. Receiver operator curve (ROC) analysis determined the predictive accuracy of this model. Results: The 6-week postoperative seizure freedom dropped to 41% at the last follow-up. The seizure-free group lived longer (100.69 months, 95% CI = 84.3-116.99 (60%)) than those with persistent postoperative seizures (27.92 months, 95% CI = 14.99-40.86). Statistically significant predictors (preoperative seizure control status, extent of resection, tumor extension to temporal lobe, and lack of postoperative adjuvant therapy) were used to compute a risk score, the score ranging from 0 to 9. A score of four most optimally distinguished the risk of postoperative seizures with an area under the ROC of 91.4% (95% CI: 84.1%, 98.7%, P < 0.001). Conclusion: In our experience, around 60% of patients obtained seizure freedom after surgery, which reduces over time. Control of seizures paralleled survival outcomes. Our proposed scoring system may help tailor management strategies for these patients.

Clinicoradiologic Risk Stratification and Outcome Assessment in Symptomatic Intracranial Arachnoid Cyst Managed Over Fifteen Years.

BACKGROUND: Arachnoid cysts (ACs) are developmental anomalies formed by splitting the arachnoid membrane's layers. ACs contribute around 2% of all intracranial space-occupying lesions. ACs are more prevalent in children. Because of varied clinical presentation, there has been a constant need for clinicoradiologic risk stratification with a possible role in outcome prediction. The present study describes the management strategies and outcomes in symptomatic intracranial ACs. METHODS: All biopsy-proven symptomatic patients who underwent surgical management over last 15 years were included in this study (January 2008-December 2022), while those with non-conclusive biopsies were excluded. Patients presenting with acute deterioration were managed in the emergency department with or without cerebrospinal fluid diversion and decompression of the AC. The microsurgical or endoscopic approach was the preferred surgical modality. Postoperative clinicoradiologic improvement was evaluated at 3 months follow-up visit. RESULTS: A total of 108 patients were analyzed in this retrospective observational study. The median age of the patients was 27.5 years (range, 1 to 76 years). Headache was the most typical clinical presentation. Supratentorial ACs (n = 59, 54.6%) were higher than the infratentorial ACs (n = 49, 45.4%). Forty-seven patients belonged to the pediatric age group (<18 years), and seizure was their presenting complaint. In this observational study, there was no statistical difference in operative duration between microsurgical technique versus endoscopic decompression (P= 0.23). CONCLUSIONS: ACs are uncommon brain lesions having a broad spectrum of symptoms. The location and clinical presentation of ACs decide the preferred surgical approach. Individuals in high-risk groups must be treated on priority to achieve long-term relief of symptoms.

Looking Beyond the Anterolateral Skull Base with Frontotemporal Dural Fold Unlocking and Extradural Clinoidectomy: A Series of 17 Cases Deciphering the Translation from a Cadaver to Real, and Real to Pathologically Distorted Anatomy.

Objective: This article aims to discuss the surgical nuances and major adjustments necessary in unlocking the frontotemporal dural fold (FTDF) and extradural anterior clinoidectomy (EDAC) in actual cases, allowing translation from the cadaveric to a clinical scenario. Materials and Methods: We retrospectively reviewed the technical details of 17 procedures over 8 years, where both the initial steps (FTDF unlocking and EDAC) were performed. Lesions involving or extending to the anterolateral skull base, like the suprasellar cistern, optico-carotid cistern, interpeduncular cistern, petrous apex, and cavernous sinus, were included. The clinical data of the patients were retrieved retrospectively from the hospital information system (HIS) and in-patient records. This study was approved as a multicenter individual project with IEC No: 2020-342-IP-EXP-34. Results: An illustrated note of the common steps and outcome of the 17 procedures of unlocking the FTDF and EDAC done is presented. The technique provided adequate exposure in performing aneurysmal clipping (posterior communicating artery [P. com], basilar top, and superior hypophyseal artery [SHA] aneurysm), giant pituitary adenoma (Wilson Hardy grade 4E, n = 2), fifth nerve schwannoma (n = 4), right Meckel's cave melanoma, cavernous hemangioma (n = 4), petroclival meningioma (n = 2), and clival chordoma. Temporary and permanent cranial nerve palsy as a procedure-related complication was seen in 11.8% (n = 2) each. Complete excision was achieved in 13 (n = 13/14) patients with tumors. Conclusion: FTDF unlocking and EDAC are elegant procedures providing reasonable access to the anterolateral skull base for myriad pathologies. Brain bulge, cavernous sinus bleeding, and losing the plane of dural duplication were significant challenges in switching from cadaveric to a clinical scenario.

An Analysis of Temporal Trend of Incidence of Post-Resection Cerebrospinal Fluid Diversion in Pediatric Posterior Fossa Tumor Patients and the Predictive Factors.

Objective: We aim to find the temporal trend of incidence of post-resection cerebrospinal fluid (CSF) diversion (ventriculoperitoneal [VP] shunt/endoscopic third ventriculostomy [ETV]) in pediatric posterior fossa tumor (pPFT) patients with no pre-resection CSF diversion and the possible clinical predictors. Methods: We reviewed 108 operated children (age ≤16 years) with PFTs, from 2012 to 2020, at a tertiary care center. Patients with preoperative CSF diversion (n = 42), lesions within cerebellopontine cistern (n = 8), and those lost to follow-up (n = 4) were excluded. Life table, Kaplan-Meier curve, univariate and multivariate analyses were used to determine CSF-diversion-free survival and independent predictive factors, with significance defined as P < 0.05. Results: The median (IQR) age was 9 (7) years (M: F: 2.5:1). Mean (±SD) duration of follow-up was 32.43 ± 21.3 months. 38.9% of patients (n = 42) needed post-resection CSF diversion. Of these, 64.3% (n = 27) were done in early (≤ 30 days), 23.8% (n = 10) in intermediate (>30 days to ≤6 months), and 11.9% (n = 5) in late (≥6 months) postoperative period (P-value < 0.001). Preoperative papilledema (HR: -5.8, 95%CI: 1.7-5.8), periventricular lucency (PVL) (HR: 6.2, 95%CI: 2.3-16.6), and wound complication (HR: 3.8, 95%CI: 1.7-8.3) were found on univariate analysis as significant risk factors for early post-resection CSF diversion. On multivariate analysis, PVL on preoperative imaging (HR: -4.2, 95%CI: 1.2-14.7, P = 0.02) was identified as an independent predictor. Preoperative ventriculomegaly, raised intracranial pressure and intraoperative visualization of CSF egress from the aqueduct were not found to be significant factors. Conclusion: Significantly high incidence of post-resection CSF diversion in pPFTs occurs in early (≤30 days) postoperative period, with preoperative papilledema, PVL, and wound complication being its significant predictive factors. Postoperative inflammation, causing edema and adhesion formation can be one of the important factors for post-resection hydrocephalus in pPFTs.

Anterior Skull Base Meningioma: Surgical Approach and Complication Avoidance.

Introduction Endoscopic endonasal approach (EEA) and keyhole transcranial approaches (TCAs) are being increasingly used in anterior skull base meningioma (ASBM) surgery. Objective We compare tumor resection rates and complication profiles of EEA and supraorbital keyhole approach (SOKHA) with conventional TCAs. Methods Fifty-four patients with ASBM (olfactory groove meningioma [OGM], n = 19 and planum sphenoidale/tuberculum sellae meningioma [PSM/TSM], n = 35) operated at a single center over 7 years were retrospectively analyzed. Results The overall rate of gross total resection (GTR) was higher in OGM (15/19, 78.9%) than PSM-TSM group (23/35, 65.7%, p = 0.37). GTR rate with OGM was 90% and 75% with TCA and EEA. Death ( n = 1) following medical complication (TCA) and cerebrospinal fluid leak requiring re-exploration ( n = 2, one each in TCA and EEA) accounted for the major complications in OGM. For the PSM/TSM group, the GTR rates were 73.3% ( n = 11/15), 53.8% ( n = 7/13), and 71.4% ( n = 5/7) with TCA, EEA, and SOKHA, respectively. Seven patients (20%) of PSM-TSM developed major postoperative complications including four deaths (one each in TCA and SOKHA, and two in EEA groups) and three visual deteriorations. Direct and indirect vascular complications were common in lesser invasive approaches to PSM-TSM especially if the tumor has encased intracranial arteries. Conclusion No single approach is applicable to all ASBMs. TCA is still the best approach to obtain GTR but has tissue trauma-related problems. SOKHA may be a good alternative to TCA in selected PSM-TSMs, while EEA may be an alternate option in some OGMs. A meticulous patient selection is needed to derive reported results of EEA for PSM-TSM.

Posterior Fossa Midline Epidermoid Tumors: Role of the Inferior Medullary Velum and a Proposed New Imaging Classification.

BACKGROUND: Posterior fossa midline epidermoid tumors (PFMETs) include the epidermoid tumors of the cisterna magna (CM) and fourth ventricle (FV). OBJECTIVE: To report tumor epicenter-based classification of PFMETs and its clinical and surgical implications with outcome. METHODS: On retrospective analysis of operated cases of intracranial epidermoid tumors, 19 (N = 19) patients having tumor epicenter within FV, CM, or both were included. Cerebellopontine and prepontine cistern epidermoid were excluded. Tumor location was decided based on preoperative MRI and intraoperative findings. Major complication was defined as new onset or worsening of cranial nerve (CN) deficit, sensory motor impairment, or tracheostomy. RESULTS: The mean (±SD) age of the patients was 42.0 ± 11.6 years (range 25-61 years), with no sex predilection (male:female: 1:0.9). The most common symptoms were cerebellar dysfunction, headache, vomiting, and diplopia. Common CNs affected were VII, V, lower cranial nerve, and VI. The PFMETs were classified based on tumor epicenter as type 1 (tumor epicenter in CM, n = 4/21.1%), type 2 (FV, n = 5/26.3%), and type 3 (involved CM and FV, n = 10/52.6%). Type 2 tumors had a higher incidence of raised intracranial pressure and only facial nerve palsy as preoperative CN deficit. Type 1 tumors had the least incidence of postoperative major complications. Type 3 tumors were the largest and had a greater incidence of brainstem adhesion and postoperative complications. The tumor size, duration of symptoms, and patient age were higher in patients with brainstem adhesion (5.3 ± 1.0 cm, 21 ± 16 months, 44.1 ± 9.2 years) as against its absence (4.8 ± 1.3 cm, 11.2 ± 7.3 months, 38.2 ± 11.7 years). Inferior medullary velum and tela choroidea have a critical role in tumorogenesis, tumor extension, and brainstem adhesion. CONCLUSION: PFMETs can be classified into 3 subtypes based on tumor epicenter having clinical and surgical implications. Less aggressive dissection and near total excision in the presence of brainstem adhesion yield favorable outcomes.

"Undercutting of the corresponding rib": a novel technique of increasing the length of donor in intercostal to musculocutaneous nerve transfer in brachial plexus injury.

Intercostal nerves (ICN) are often utilized as donors for various neurotization procedures in brachial plexus injuries. ICN to musculocutaneous nerve (MCN) transfer is usually a standard in pan brachial plexus injuries, in order to restore flexion at the elbow. A tensionless co-aptation of the donor-recipient nerves often necessitates either a distal dissection of the ICNs where the number of fascicles is rather low or a proximal dissection, often at the cost of dissection of the serratus anterior digitation with a risk of later fibrosis and adhesion. We report two cases of pan brachial plexus injuries where ICN-MCN transfer was performed to restore elbow function. These patients underwent clinical and electrodiagnostic evaluation before surgery. We used the standard technique of harvesting ICNs 3-5, with our technical modification of "undercutting of rib" for increasing the donor length. The procedure was applied in two patients with pan brachial plexus injury (mean age = 23). Mean duration since the injury to surgery was ten months. Both patients underwent tensionless anastomosis with a combination of suture and fibrin glue co-aptation. While one patient had some improvement in elbow flexion, another one was under active rehabilitation protocol during follow-up. We found that undercutting of the ribs near serratus digitations can allow mobilization of the ICN from its groove, which in turn lengthens the donor nerve length without violating the serratus anterior digitations and without too anterior dissection of the nerve. It can be a viable option when a tensionless co-aptation at the axilla is otherwise not feasible intraoperatively.

Seizure-outcome after surgery of low-grade epilepsy associated neuro-epithelial tumors.

BACKGROUND: Most patients with glioneuronal tumors present with seizures. Although several studies have shown that greater extent of resection improves overall patient survival, few studies have focused on postoperative seizure outcome after resection of these tumors. The aim of this study was to characterize seizure control rates in patients undergoing glioneuronal tumor resection and evaluate the association between poor seizure outcome and tumor recurrence or progression. METHODS: The study population included patients who had undergone resection of glioneuronal tumors between 2014 and 2019 at our institution. Seizure outcome was assessed using Engel grading. Preoperative seizure characteristics, tumor characteristics, surgical factors, and postoperative seizure outcomes were reviewed. RESULTS: Twenty-six patients (N.=16, temporal lobe; N.=6, frontal lobe; N.=4, parietal lobe) with mean seizures duration of 56.9-months, were assessed. Histopathologically, N.=15 dysembryoplastic neurepithelial tumor, N.=7 ganglioglioma and N.=4 Diffuse lepto-meningeal neuroepithelial tumor. There were 2 cases of complex DNET and one case of DLMNT had associated cortical dysplasia. At mean follow-up of 49.7 months, N.=20 Engel 1, N.=4 Engel 2 and N.=2 had Engel 3 outcome. N.=20 underwent gross total excision (N.=18 Engel 1 and N.=2 Engel 2) and N.=6 sub-total excision. Among the 4 patients who needed re-surgery, two were in Engel 2 and another two were in Engel 3. CONCLUSIONS: Good seizure-outcome is likely associated with extent of resection. Younger age of patient, less than one-year of seizure duration and absence of generalization of seizure are good prognostic indicators. The best seizure-control can be achieved by early surgical intervention.

Insular glioblastoma: surgical challenges, survival outcomes and prognostic factors.

BACKGROUND: Insular gliomas are unique, challenging and evoke a lot of interest amongst neurosurgeons. Publications on insular glioma generally focus on the surgical intricacies and extent of resection pertaining to the low-grade gliomas. Insular glioblastomas (iGBM) have not been analysed separately before. METHODS: Histologically proven WHO grade IV gliomas involving the insula over a 9-year period were studied. Their clinical presentation, radiological features, surgical findings and survival outcomes were assessed. Statistical methods were used to determine the favourable predictors of survival. RESULTS: Out of 27 patients (M:F = 2.9:1), 18 (66%) patients had a tumour extension beyond the insula, 10 (37%) of whom had basal ganglia involvement. Total, near total and subtotal excisions were performed in 7 (26%), 9 (33%) and 11 (40.7%) patients, respectively. Twenty-three patients had glioblastoma, while four had gliosarcoma. IDH mutation was negative in six of the seven patients where it was done. Median overall survival was 5 months. Multivariate analysis showed that a female gender (p = 0.013), seizures in the preoperative period (p = 0.048) and completion of adjuvant therapy (p = 0.003) were associated with a longer survival. CONCLUSION: Insular glioblastomas have a poor prognosis. Insular location and certain tumour characteristics often limit the extent of resection of iGBMs. Moreover, postoperative complications sometimes negate the advantages of a radical resection. A female gender, presentation with seizures and completion of adjuvant chemoradiotherapy appear to be good prognostic factors.

Endoscopic Management of Malignant Tumors of Paranasal Sinus and Nasal Cavity: An Institutional Experience.

Malignant tumors of sinonasal region are rare and affect less than 1 in 100,000 people per year. They are histologically diverse group and potentially pose significant management problems due to their proximity to the orbit and intracranial cavity. Although squamous cell carcinoma (SCC) is most common malignant tumor of paranasal cavity, tumors like adenocarcinoma, olfactory neuroblastoma, malignant melanoma, adenoid cystic carcinoma, sarcomas, haemoproliferative tumors, e.g. lymphoma may also occur. Retrospectively study was done in a tertiary care institute from January 2008 to December 2018 in India. Inclusion criteria-all biopsy proven PNS malignancy patients operated by endoscopic approach, irrespective of age and gender. Exclusion criteria- patients diagnosed with nasopharyngeal carcinoma, skin involvement, gross orbital involvement (muscle invasion), metastasis, operated by open approaches. 46 patients who underwent endoscopic tumor removal were reviewed. 36 (78.2%) were males and 10 (4.6%) females. Most common tumor in our study was adenoid cystic carcinoma. Recurrence was seen in 6 patients. Palliative therapy was given to all patients with recurrence. Management of malignant PNS tumor involving anterior skull base is multidisciplinary. R0 resection should be main goal in all malignant PNS malignancy. Tumors invading unresectable areas like cavernous sinus, brain parenchyma, carotids can be left in these places followed by palliation except in cases of squamous cell carcinoma. If R0 cannot be achieved surgically in SCC than patient should be considered inoperable and send for palliation. T1-T3 PNS malignant tumors can be managed by endoscopic approach followed by adjuvant therapy after a period of 6 weeks. Endoscopic excision should be converted to endoscopic assisted open approach in case of T4 tumors. We have tried to give a management protocol for management of malignant PNS tumors. Level of evidence: II.

The current status and surgical outcome of the minimally invasive techniques for lumbar interbody fusion in India: A systematic review and meta-analysis.

Objective: The global shift of trends to minimally invasive spine (MIS) surgery for lumbar degenerative diseases has become prominent in India for few decades. We aimed to assess the current status of MIS techniques for lumbar interbody fusion and their surgical outcomes in the Indian population. Materials and Methods: A systematic review (following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines) was performed using PubMed and Google Scholar till November 2020. The primary (visual analog scale [VAS] and oswestry disability index [ODI] scores; intraoperative blood loss; duration of surgery; duration of hospital stay, and fusion rate) and secondary (wound-associated complications and dural tear/cerebrospinal fluid (CSF) leak) outcomes were analyzed using Review Manager 5.4 software. Results: A total of 15 studies comprising a total of 1318 patients were included for analysis. The pooled mean of follow-up duration was 26.64 ± 8.43 months (range 5.7-36.5 months). Degenerative spondylolisthesis of Myerding grade I/II was the most common indication, followed by lytic listhesis, herniated prolapsed disc, and lumbar canal stenosis. The calculated pooled standard mean difference (SMD) suggested a significant decrease in postoperative ODI scores (SMD = 5.53, 95% confidence interval [CI] = 3.77-7.29; P < 0.01) and VAS scores (SMD = 6.50, 95% CI = 4.6-8.4; P < 0.01). The pooled mean blood loss, duration of postoperative hospital stay, duration of surgery, and fusion rate were 127.75 ± 52.79 mL, 4.78 ± 3.88 days, 178.59 ± 38.69 min, and 97.53% ± 2.69%, respectively. A total of 334 adverse events were recorded in 1318 patients, giving a complication rate of 25.34%. Conclusions: Minimally invasive transforaminal lumbar interbody fusion (TLIF) is the most common minimally invasive technique employed for lumbar interbody fusion in India, while oblique lumbar interbody fusion is in the initial stages. The surgical and outcome-related factors improved significantly after MIS LIF in the Indian population.

An Institutional Experience and Literature Review on Iatrogenic Major Vascular Injury in Neurosurgery: Proposal of a Management Algorithm.

Background: Major vessel injury is among the most dreaded complications of any neurosurgical procedure. Once intraoperatively tamponaded, it can present in the form of pseudoaneurysm, dissecting aneurysm or complete occlusion of vessel. These injuries are often associated with very high morbidity and mortality. The literature available on this topic is limited and our understanding remains limited. Objective: In this article, we present our surgical experience with iatrogenic aneurysms and present a review of literature. Methods and Material: We conducted a retrospective analysis of all patients with major vessel injury during surgery from a prospectively maintained database from January 2012 to February 2020. Results: A total of 15 patients developed iatrogenic aneurysms following a major vessel injury during various neurosurgical procedures. The most common vessel injured was vertebral artery (n = 9) in craniovertebral junction (CVJ) anomalies and ossification of posterior longitudinal ligament (OPLL) followed by internal carotid artery injury (n = 5) in sellar and parasellar pathologies. One patient developed basilar artery injury during endoscopic third ventriculostomy (ETV). Eight patients had pseudoaneurysm and seven had dissecting aneurysm with or without complete thrombosis of the involved artery. A total of two patients died after vascular injury and remaining thirteen patients survived and discharged. Conclusions: The adage "prevention is better than cure" applies most aptly in such cases. Any major vessel injury should be followed by immediate angiography and subsequent early management. The endovascular management is more favorable as these aneurysms are difficult to clip due to the absence of a neck and fragile wall.

Cerebellopontine Angle Epidermoids: Comparative Results of Microscopic and Endoscopic Excision Using the Retromastoid Approach".

Background Densely packed neurovascular structures, often times inseparable capsular adhesions and sometimes a multicompartmental tumor extension, make surgical excision of cerebellopontine angle epidermoids (CPEs) a challenging task. A simultaneous or an exclusive endoscopic visualization has added a new dimension to the classical microscopic approaches to these tumors recently. Methods Eighty-six patients (age: 31.6 ± 11.7 years, M:F = 1:1) were included. Nineteen patients (22.1%) had a multicompartmental tumor. Tumor extension was classified into five subtypes. Sixty-two patients underwent a pure microscopic approach (72%) out of which 10 patients (16%) underwent an endoscope-assisted surgery (11.6%) and 24 patients (28%) underwent an endoscope-controlled excision. Surgical outcomes were retrospectively analyzed. Results Headache (53.4%), hearing loss (46.5%), and trigeminal neuralgia (41.8%) were the leading symptoms. Interestingly, 21% of the patients had at least one preexisting cranial nerve deficit. Endoscopic assistance helped in removing an unseen tumor lobule in 3 of 10 patients (30%). Pure endoscopic approach significantly reduced the hospital stay from 9.2 to 7.3 days ( p = 0.012), and had a statistically insignificant yet a clearly noticeable lesser incidence of subtotal tumor excision (0 vs. 10%, p = 0.18) with comparable cranial nerve deficits but with a higher postoperative cerebrospinal fluid (CSF) leak rate (29% vs. 4.8%, p = 0.004). Conclusion Endoscope assistance in CPE surgery is a useful addition to conventional microscopic retromastoid approach. Pure endoscopic excision in CPE is feasible, associated with a lesser duration of hospital stay, better extent of excision in selected cases, and it has a comparable cranial nerve morbidity profile albeit with a higher rate of CSF leak.

Balancing the Extent of Resection and Ischemic Complications in Insular Glioma Surgery: Technical Nuances and Proposal of a Novel Composite Postoperative Outcome Index.

Background: Maximal safe resection remains the most desired goal of insular glioma surgery. Intraoperative surgical adjuncts provide better tumor visualization and real-time "safety" data but remain limited due to a high cost and limited availability. Objective: To highlight the importance of anatomical landmarks in insular glioma resection and avoidance of vascular complications. We also propose to objectify the onco-functional balance in insular glioma surgery. Methods: Forty-six insular gliomas operated upon by a single surgeon between January 2015 and February 2020 were reviewed, focusing on the operative technique and clinical outcomes. A novel composite postoperative outcome index (CPOI) was designed, comprising the extent of resection and permanent postoperative deficits, and utilized to assess the surgical outcomes. Results: Gross-total, near-total, and subtotal resections were achieved in 10.9%, 52.1% (n = 24), and 36.9% (n = 17) patients, respectively. The median overall survival (OS) was 20 months (95% CI = 9.56-30.43). CPOI was optimal in 38 patients (82.6%). A well-defined tumor margin (P = 0.01) and surgeon's experience (P = 0.04) were significantly associated with an optimal CPOI. Out of seven (15.2%) patients who developed permanent neurological deficits, three (6.5%) patients had severe disability. Favorable prognostic factors of survival included younger age (<40 years) (P = 0.002), tumors with only frontal lobe extension (P = 0.011), tumors with caudate head involvement (P = 0.04), and non-glioblastoma histology (P = 0.006). Conclusion: Tumor margin and increasing surgeon experience are critical to an optimal postoperative outcome. Respecting the basi-sulcal plane is key to lenticulostriate artery preservation. Caudate head involvement is a new favorable prognostic factor in insular gliomas.

Thirteen-and-a-half Syndrome Secondary to the Brainstem Cavernoma.

Background: "Thirteen-and-a-half" is a newly described clinical syndrome characterized by the combination of the one-and-a-half syndrome with fifth and seventh cranial nerve nuclei involvement (11/2 + 5 + 7 = 131/2). To the authors' knowledge, this is the first report of the thirteen-and-a-half syndrome secondary to pontine cavernoma and, overall, only the second reported case of this syndrome in the literature till date. Case Report: A 20-year-old man presented with the clinical features suggestive of the thirteen-and-a-half syndrome, explained radiologically by pontine cavernoma. We operated him using a suboccipital transvermian approach and he is doing well at 2.5 years follow-up. Interestingly, his one-and-a-half syndrome has partially improved to left horizontal gaze palsy. Conclusion: The clinical appreciation of the thirteen-and-a-half syndrome precisely localizes the lesion to ipsilateral dorsal pontine tegmentum. Neurosurgeons must be aware of the newly described "one-and-a-half- plus" syndromes as they help in a better understanding of pathoanatomy caused by different disease processes in the brainstem.

Quantitative assessment of brainstem distortion in vestibular schwannoma and its implication in occurrence of hydrocephalus.

PURPOSE: Anatomical distortion directly affects the clinical status of patients with vestibular schwannomas (VSs). It may vary for a given tumor size due to variability in posterior fossa anatomy. We aimed to quantitatively assess brainstem distortion (BSD) and review its role in occurrence of hydrocephalus associated with VSs. METHODS: Sixty-six patients with small (<3 cm, n= 8; 12.1%); large (3-4 cm; n= 26; 39.4%) and giant (>4 cm; n= 32; 48.5%) VSs were included. Cystic VSs were excluded. Tumor size, tumor-extent, linear displacement (LD; distance between line bisecting pons (line 1) and posterior fossa midline (line 2)) and angular distortion (AD; angle subtended between lines 1 and 2) in axial-T2-MRI section through pons, and their effect on hydrocephalus were assessed. RESULTS: Significant BSD occurred in a younger age (p value = .004/.003), larger-sized tumor (p value = .001/.002), hydrocephalus (p value = .001/.001), trigeminal (V) nerve palsy (p value = .004/.003) and long tract signs (p value = .001/.034). Tumors crossing midline had significant association with hydrocephalus (p value = .003). LD increased progressively even for 4-5 cm-sized tumors while AD stabilized. Receiver operating characteristic (ROC) curve revealed that diagnostic accuracy of LD (area under the ROC curve (AUROC): 78.9% (95% CI: 67.2%, 90.5%, p < .001)), AD (AUROC:77.6% (95% CI:65.8%, 89.5%, p < .001)) and LD × AD (AUROC:80.3% (95% CI: 69.2%, 91.2%, p < .001)) for predicting occurrence of hydrocephalus was better than tumor size (AUROC: 66.7% (95% CI: 53.5%, 79.9%, p < .05). Cut-off values of LD and AD for predicting occurrence of hydrocephalus were 6.25 mm and 14.6°, respectively. Hydrocephalus was significantly more when both LD was greater than  6.25 mm and AD was greater than 14.5° (p value = .034). The role of LD and AD in influencing hydrocephalus was greater than categorization based on tumor size (Spearman's correlation coefficient: 0.535 and 0.248, respectively). Hydrocephalus occurred at a lesser cut-off value of LD and AD when compared to long tract signs. CONCLUSIONS: LD and AD values in VSs have a significantly greater influence in the development of hydrocephalus compared to tumor size, and may aid, more reliably, in the prediction of hydrocephalus.

Intraventricular Craniopharyngiomas-Overcoming Their Relative Inaccessibility: Institutional Experience With a Review of Literature.

Introduction: Craniopharyngiomas constitute 2-4% of intracranial neoplasms. Intraventricular craniopharyngiomas (IVCrs) are the rarely encountered varieties of these lesions. Objective: The objective of the study was to study the special features in clinical presentation, imaging, management, and surgical outcome of IVCrs. Materials and Methods: This retrospective analysis included the combined experience from two tertiary care institutions. Medical records of histopathologically proven cases of IVCrs from January 1994 to June 2021 were assessed, and images were analyzed based on the criteria by Migliore et al. for inclusion of solely intraventricular lesion with the third ventricular ependyma demarcating it from the suprasellar cistern. Results: Among the 25 patients included (mean age: 35.4 years), the most common presentation included headache (n = 21, 84%), vomiting and other features of raised ICP (n = 18, 72%), visual complaints (n = 12, 48%), and endocrinopathies (n = 11, 44%). Fifteen had predominantly cystic tumors, two were purely solid, and eight were of mixed consistency. Primary open microsurgical procedures were performed in 18 (72%) patients, of which four (16%) were endoscope-assisted. Seven (28%) underwent a purely endoscopic procedure. One underwent a staged surgery with endoscopic cyst fenestration and intracystic interferon (IFN)-alpha therapy, followed by microsurgical excision. Complete excision was achieved in 10 patients, near-total in nine, and partial excision in six. Four patients underwent a ventriculoperitoneal shunt (one before the definitive procedure). At a median follow-up of 36 months (range:11-147 months), five patients developed a recurrence, and one had a stable small residue. This patient and two others with small cystic recurrences were observed. One patient was managed with radiotherapy alone. Another underwent re-surgery after a trial of radiotherapy, and the last patient developed a local recurrence, which was managed with radiotherapy; he then later developed an intraparenchymal recurrence, which was operated. Conclusion: Purely IVCrs present with raised intracranial pressure, and visual disturbances are less common. Their deep-seated location and limited surgical field-of-view makes minimally invasive endoscopic-assisted surgery most suitable for their excision. The thin-walled cystic lesions may be occasionally adherent to the ependymal wall in close vicinity to the thalamus-hypothalamus complex, making complete excision difficult. Their responsiveness to radiotherapy, often leads to a gratifying long-term outcome.