Safety and Efficacy of Biopsy in Patients with Diffuse Intrinsic Pontine Gliomas.

BACKGROUND: Diffuse intrinsic pontine gliomas are aggressive tumors that carry a poor prognosis with a 2-year survival rate of <10%. The imaging appearance is often pathognomonic, and surgical biopsy is not mandatory to initiate treatment in children. Studies of biopsy samples provide insight into the disease's molecular pathobiology and open prospects for targeted therapy. This study was conducted to determine the diagnostic yield and safety of stereotactic biopsies. METHODS: This is a prospective observational study from a single tertiary health care center. All patients with clinical and radiological features diagnostic of diffuse intrinsic pontine gliomas (DIPGs) who underwent biopsy from July 2018 to June 2023 were included. Biopsies were performed using either stereotactic frame-based, frameless, or endoscopic techniques. RESULTS: A total of 165 patients with DIPGs were evaluated in the study period. The option of biopsy with its associated risks and benefits was offered to all patients. A total of 76 biopsies were performed in 74 patients (40 children and 34 adults, including 2 repeat biopsies). The median age was 15 years. Diffuse midline gliomas, H3K27M altered, was the most common histopathological diagnosis (85% pediatric and 55.9% adults). The diagnostic efficacy of the procedure was 94.7%. The complication rate was 10.8%, with no permanent neurological deficits due to surgery. There was no procedure-related mortality. CONCLUSIONS: Establishing the safety of the procedure could be an important step toward popularizing the concept, which might offer a better understanding of the disease. Brainstem eloquence and a lack of direct benefit to patients are the primary obstacles to brainstem biopsy.

Prognostic Factors and Outcomes in World Health Organization Grade 1 and Grade 2 Intracranial Meningiomas-5-Year Institutional Experience.

BACKGROUND: Meningiomas are the most frequent primary intracranial tumor. While histological grade and grade of excision are established predictors of recurrence, the predictive ability of other clinical features, such as the role of radical excision of dural attachment and postoperative radiation therapy in intermediate-risk groups, remains unknown. METHODS: Clinical and radiological features and surgical details were analyzed in 451 World Health Organization (WHO) grade 1 intracranial meningiomas and 248 WHO grade 2 meningiomas operated on between 2010 and 2015. Outcomes were assessed in 352 WHO grade 1 and 208 WHO grade 2 meningiomas, studying the effect of extent of resection and use of radiation therapy. Kaplan-Meier analysis was used to determine differences in survival by extent of resection and use of postoperative radiation therapy in the treatment of the meningiomas. RESULTS: The mean age of the cohort was 46.3 years, with a female predominance. On univariate analysis, sex, WHO grade, and Simpson grade were significant predictors of recurrence. On multivariate analysis, WHO grade and Simpson grade remained significant predictors of recurrence. Recurrence was significantly associated with poor performance status and mortality. Postoperative radiation significantly improved progression-free survival among patients with grade 2 meningiomas who underwent gross total resection, but not among patients with grade 1 and grade 2 meningiomas who underwent subtotal resection. CONCLUSIONS: WHO grade and Simpson grade are independent predictors of recurrence in meningiomas. Regardless of WHO grade, gross total resection must be performed when possible, and postoperative radiation therapy may be recommended in grade 2 meningiomas.

Factors Influencing Long-Term Outcomes of Single-Session Gamma Knife Radiosurgery in Large-Volume Meningiomas >10 cc.

INTRODUCTION: Meningiomas are the most common primary intracranial tumour. Gamma knife radiosurgery (GKRS) is a frequently employed non-invasive method of treatment, with good remission rates and low morbidity in literature. However, the role of GKRS in the management of "large" meningiomas is unclear, with reported outcomes that vary by centre. We aimed to assess the factors that influence long-term outcomes following GKRS in meningiomas >10 cc in volume. METHODS: A retrospectively analysed all patients with meningiomas exceeding 10 cc in volume who underwent GKRS between January 2006 and December 2021 at the National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru. Demographic, clinical, radiological, and follow-up data were acquired, and factors associated with progression following GKRS were assessed. RESULTS: The cohort comprised 76 patients 29 males (38.2%) and 47 females (61.8%) with a mean age of 46.3 ± 11.02 years. Thirty-nine patients had been previously operated (51.3%). Meningiomas were most frequently located in the parasagittal region (26 tumours, 34.2%) and sphenopetroclival region (23 tumours, 30.3%), with mean lesion volume of 12.55 ± 5.22 cc, ranging 10.3 cc-25 cc. The mean dose administered to the tumour margin was 12.5 Gy ± 1.2 Gy (range 6-15 Gy). The median duration of clinical follow-up was 48 months, over which period radiological progression occurred in 14 cases (20%), with unchanged tumour volume in 20 cases (28.6%) and reduction in size of the tumour in 36 cases (51.4%). Progression-free survival after GKRS was 72% at 5 years, was significantly poorer among meningiomas with tumour volume >14 cc (log-rank test p = 0.045), tumours presenting with limb motor deficits (log-rank test p = 0.012), and tumours that underwent prior Simpson grade 3 or 4 excision (log-rank test p = 0.032). CONCLUSIONS: Meningiomas >10 cc in volume appear to display a high rate of progression and subsequent need for surgery following GKRS. Primary surgical resection, when not contraindicated, may be considered with GKRS serving an adjuvant role, especially in tumours exceeding 14 cc in volume, and presenting with limb motor deficits. Long-term clinical and radiological follow-up is essential following GKRS as the response of large meningiomas may be unpredictable.

Role of Optical Coherence Tomography in Predicting Visual Outcome after Surgery for Sellar and Supra-Sellar Tumors.

BACKGROUND: Almost one-fifth of patients undergoing surgery for sellar/supra-sellar tumors do not gain a significant improvement in their vision. Various methods have been described to predict prospective visual outcomes in them, although they lack uniformity. OBJECTIVE: The study was conducted to predict visual outcomes following surgery for sellar and supra-sellar tumors compressing the anterior optic pathway based on pre-operative optical coherence tomography (OCT) parameters. METHODS AND MATERIALS: This was a record-based observational descriptive longitudinal study done in a tertiary care center in India. Thirty-seven patients (74 eyes) diagnosed with sellar supra-sellar lesions were included in the study. Patients' ophthalmic evaluations, done pre-operatively and 3 months post-operatively, were reviewed. Spectral-domain OCT and segmentation were done using the automated segmentation technology of Spectralis software. The thickness of the respective layers was measured. RESULTS AND CONCLUSIONS: The mean age of the study population was 42.68 years. Eyes with a pre-operative visual acuity component of VIS (visual impairment score) ≤61, pre-operative ganglion cell layer thickness ≥26.31 um, a pre-operative inner plexiform layer thickness of ≥25.69 um, a pre-operative ganglion cell inner plexiform layer thickness of 52.00 um, pre-operative ganglion cell complex thickness ≥84.47 µm, and a pre-operative inner retinal layer thickness of ≥205.25 µm were more likely to have an improved visual outcome. Eyes with a pre-operative duration of visual symptoms of ≥15 months, VIS ≥126.50, a pre-operative decimal visual acuity of <0.035, a pre-operative visual field index of ≤8%, a pre-operative macular thickness of ≤287.06 um, a pre-operative macular RNFL (retinal nerve fiber layer) thickness ≤66.00 µm, and a pre-operative peri-papillary RNFL thickness ≤64.62 µm were unlikely to have visual improvement.

Usefulness of Opening the Diaphragma Sellae Before Transecting Interclinoidal Ligament for Endoscopic Endonasal Transoculomotor Triangle Approach: Technical Nuances and Surgical Outcomes.

OBJECTIVE: Opening the oculomotor triangle (OT) and removing the posterior fossa lesion by endoscopic endonasal approach (EEA) is challenging for even an experienced endoscopic neurosurgeon. We summarize the treatment experience and technical nuances with EEA for resection of pituitary neuroendocrine tumors and cavernous sinus (CS) meningiomas invading through the OT. METHODS: Between 2018 and 2022, 8 patients, comprising 5 with pituitary neuroendocrine tumors (3 with nonfunctioning and 2 with somatotroph tumors with increased levels of growth hormone) and 3 CS meningiomas, were treated using an endoscopic endonasal transoculomotor triangle approach. The critical surgical technique is continuously opening the diaphragma sellae from medial to lateral toward the interclinoidal ligament and transecting it to enlarge the OT. We evaluated preoperative tumor size, previous surgical history, preoperative symptoms, extent of tumor resection, histopathology, and postoperative complications for all patients. RESULTS: The gross total resection (defined as complete removal) in 3 patients (38%), near-total resection (defined as >95% removal) in 4 patients (50%), and subtotal resection (defined as ≤90% removal) in 1 patient (12%) and gross total resection of tumor invading through the OT was achieved in all patients through pure EEA. Two of 3 patients with visual deficits in nonfunctioning pituitary neuroendocrine tumors improved, and the other remained stable postoperatively. One patient showed transient oculomotor nerve palsy. The growth hormone level of the 2 patients with somatotroph tumors declined to normal. For 3 patients with CS meningiomas, cranial nerve palsy improved in 2 patients, whereas the other patient developed increased facial numbness after surgery. CONCLUSIONS: The endoscopic endonasal transoculomotor triangle approach is an efficient surgical option for tumors with CS invasion and OT penetration.

Evaluating the Diagnostic Efficacy of 99mTc-Methionine Single-Photon Emission Computed Tomography-Computed Tomography: A Head-to-Head Comparison with 11C-Methionine Positron Emission Tomography-Magnetic Resonance Imaging in Glioma Patients.

Background: Amino acid positron emission tomography (PET) imaging plays a significant role in the diagnosis of gliomas and in differentiating tumor recurrence from necrosis. In this study, the authors evaluated the diagnostic efficacy of [99mTc]Tc-methionine single-photon emission computed tomography-computed tomography (SPECT-CT) in comparison with [11C]methionine PET-magnetic resonance imaging (MRI) in delineating tumors. Methods: Thirty-one (primary: 16 and postoperative: 15) patients of confirmed (either MRI or histopathological proven) glioma underwent both [99mTc]Tc-methionine SPECT-CT and [11C]methionine PET-MRI. A comparative analysis was performed between SPECT, PET, and MR images to calculate the concordance between the modalities and to evaluate the diagnostic efficacy of the [99mTc]Tc-methionine SPECT. Results: [99mTc]Tc-methionine SPECT showed comparable uptake in the tumor lesions in comparison to [11C]methionine PET. A significant and strong positive correlation was observed between the volume of tumor (Vt) in PET and Vt MR (p < 0.004). Likewise, a significant and strong positive correlation was found between Vt SPECT and Vt MR. [99mTc]-methionine has a sensitivity and specificity of 91% and 75%, respectively, compared with 82% and 100% for [11C]methionine in postoperative cases to differentiate the tumor recurrence from necrosis. The sensitivity and specificity of [99mTc]Tc-methionine was 92% and 100%, respectively, compared with 92% and 67% for [11C]methionine in primary tumors. Conclusion: [99mTc]Tc-methionine SPECT-CT is as equally good as [11C]methionine for diagnosing and differentiating it from necrosis especially in high-grade glioma.

Surgical Outcome of Torcula Herophili Meningioma: An Institutional Experience.

INTRODUCTION: Resection of meningiomas (THMs) at the torcular Herophili poses challenges to surgeons due to complex regional anatomy. The current study aims to evaluate factors affecting the extent of resections, progression-free survival, and the role of radiation. METHODS: We did a retrospective study of all the THM patients treated at our institute between May 1987 and June 2022. The demographic data, signs and symptoms, surgical notes, postoperative details, and radiotherapy were gathered retrospectively. Survival analysis was done with Kaplan-Meier tests along with predictors of the extent of resection as well as recurrence. RESULTS: A total of 39 patients qualified to be included in the study, with 10 male patients (male:female 1:2.9) and an average age of 50.8 years. The average follow-up duration was 75.9 months. Simpson's grade 2 excision was achieved in 19 (48.7%) patients, followed by Simpson's grade 3 excision in 17 patients (43.6%). Progression-free survival in subtotal resection was 60 months, and 100 months in gross total resection. Statistically, the extent of the resection was determined by the involvement of sinuses/torcula and the number of quadrants involved around torcula. A total of 16 patients received radiosurgery for the residual or small reccurrence of the lesion. Follow-up revealed reccurrence in 5 cases. CONCLUSIONS: Torcular meningiomas are relatively uncommon, described in few reports, and represent a therapeutic dilemma. Though some experts recommend complete removal of tumor and reconstruction of the sinus, others suggest maximum safe resection, followed by radiosurgery. The present study reflects reasonable control of the residual lesion with radiosurgery after maximum safe resection.

Pediatric shunt failure: finding predictability in the sea of uncertainty.

OBJECTIVE: Shunt malfunction is a complication that can have devastating implications. In this study, the authors aimed to evaluate the rate of shunt revision in a single institution over 5 years and to determine the factors associated with shunt revision in the pediatric population. METHODS: This retrospective report assimilated data from all patients ≤ 18 years old who underwent shunt surgery between January 2015 and April 2021 at the authors' institute with a minimum of 3 months of follow-up. Patient data regarding demographic characteristics, indications, clinical status, point of entry, operative and CSF findings, revision interval, and cause of failure were collected. RESULTS: Between January 2015 and April 2021, 1112 pediatric patients underwent initial shunt surgery at the authors' institute, among whom 934 patients met the inclusion criteria. Ninety-five patients underwent revision (shunt revision rate 10.2%). The cohort comprised 562 male and 368 female patients (no sex was recorded in 4 cases), with infratentorial tumors (37.8%) being the most common indication for the shunt. Multivariate analyses revealed that younger patient age, right-sided shunt, single surgeon, and shunt placement done in the evening and night were significantly associated with shunt failure. Among all the factors analyzed, female sex had the greatest risk of early shunt failure (OR 2.90 [95% CI 1.09-8.16], p = 0.037). The presence of prior external ventricular drainage was associated with an increased risk of multiple revisions (OR 6.67 [95% CI 1.60-32.52], p = 0.012). The most common cause of failure was obstruction, usually at the cranial end. The most common cause of distal failure was malposition of the abdominal end. CONCLUSIONS: This study identifies various factors associated with shunt failure. Various goal-directed strategies toward modifiable risk factors can significantly improve shunt survival.

Factors predicting recurrence in benign spinal nerve sheath tumors: A retrospective study of 457 patients from a single institution.

BACKGROUND: Benign Nerve sheath tumors (NST) comprise almost one-third of primary spinal tumours. The majority are sporadic. They have low rates of recurrence but an occasional recurrence may need re-surgery. The present study was designed to identify the variables that can predict the risk of their recurrence. METHODS: A retrospective chart review was done including all the histologically proven benign spinal NSTs operated between 2001 and 2019 in our institute. Demographic, operative and postoperative follow-up data were recorded. Recurrence was defined as local reappearance after definite surgical excision or symptomatic increase in size of a residual tumour on follow-up imaging studies. Statistical analysis was done to determine the significant variables associated with local recurrence. RESULTS: 457 patients with a median age of 38 years operated for 459 NSTs qualified for the study. The most frequent location of occurrence of tumours was found to be Low Cervical level (C3-C7 levels). Majority of Schwannoma were located intradurally while Neurofibroma were dumb-bell shaped and extradural. Most of the tumours had solid consistency. Post operatively, 7.7% patients developed complications. 7.8% tumours developed local recurrence after median period of 12 months. The patients developing recurrence were younger compared to nonrecurring tumors. On univariate analysis, male gender, Low cervical and Cervicothoracic junction location were associated with higher recurrence. On multivariate analysis, location at Cervicothoracic junction reached significance. CONCLUSION: Overall recurrence risk among all NST was 7.8% with a median progression free survival of 36 months. The location of tumour at cervicothoracic location was the significant risk factors for recurrence of tumour in our study.

Does Propofol Effect Site (Brain) Concentration Predicted by Target-Controlled Infusion Correlate with Propofol Measured in the Brain? An Exploratory Study in Neurosurgical Patients.

BACKGROUND: Total intravenous anesthesia with propofol can be administered by target-controlled infusion pumps, which work on the principles of pharmacokinetic modeling. While designing this model, neurosurgical patients were excluded as the surgical site and drug action site remained the same (brain). Whether the predicted set propofol concentration and the actual brain site concentration correlate, especially in neurosurgical patients with impaired blood-brain barrier (BBB), is still unknown. In this study we compared the set propofol effect-site concentration in the target-controlled infusion pump with actual brain concentration measured by sampling the cerebrospinal fluid (CSF). METHODS: Consecutive adult neurosurgical patients requiring propofol infusion intraoperatively were recruited. Blood and CSF samples were collected simultaneously when patients received propofol infusion at 2 different target effect-site concentrations-2 and 4 ug/mL. To study BBB integrity, CSF-to-blood albumin ratio and imaging findings were compared. The propofol level in the CSF was compared with set concentration using the Wilcoxon signed-rank test. RESULTS: Fifty patients were recruited, and the data were analyzed from 43 patients. There was no correlation between propofol concentration set in TCI and propofol concentration measured in blood and CSF. Though imaging findings were suggestive of BBB disruption in 37/43 patients, the mean (±standard deviation) CSF-to-serum albumin ratio was 0.0028 ± 0.002, suggesting intact BBB integrity (ratio >0.3 was considered as disrupted BBB). CONCLUSIONS: CSF propofol level did not correlate with set concentration in spite of acceptable clinical anesthetic effect. Also, the CSF-to-blood albumin measurement did not provide information on the BBB integrity.

Primary Intracranial Alveolar Soft Part Sarcoma: A Report of 3 Cases.

Alveolar soft part sarcoma (ASPS) commonly involves extremities and head and neck regions. Primary intracranial ASPS is rare. We report a series of 3 primary intracranial ASPS. These were not suspected clinically and histopathology with immunohistochemistry proved to be diagnostic in all 3 tumors.

Automated Microsurgical Tool Segmentation and Characterization in Intra-Operative Neurosurgical Videos.

Checklist based routine evaluation of surgical skills in any medical school demands quality time and effort from the supervising expert and is highly influenced by assessor bias. Alternatively, automated video based surgical skill assessment is a simple and viable method to analyse surgical dexterity offline without the need for acute presence of an expert surgeon throughout the surgery. In this paper, a novel approach and results for the automated segmentation of microsurgical instruments from the real-world neurosurgical video dataset was presented. The proposed tool segmentation model showcased mean average precision of 96.7% in detecting, and localizing five surgical instruments from the real-world neurosurgical videos. Accurate detection and characterization of motion features of the microsurgical tool from the novel annotated neurosurgical video dataset forms the key step towards automated surgical skill evaluation. Clinical Relevance- Tool segmentation, localization, and characterization in neurosurgical video, has several applications including assessing surgeons skills, training novice surgeons, understanding critical operating procedures post surgery, characterizing any critical anatomical response to the tool that leads to the success or failure of the surgery, and building models for conducting autonomous robotic surgery. Semantic segmentation, and characterization of the microsurgical tools forms the basis of the modern neurosurgery.

Delayed Vasospasm in Endoscopic Transsphenoidal Pituitary Surgery: Two Case Reports and Reviews.

Background: Cerebral vasospasm (CVS) due to injuries to arteries of the circle of willies has been reported in transsphenoidal pituitary surgeries. However, the incidence of delayed vasospasm following endoscopic transsphenoidal surgery is rare. Materials and Methods: Total 569 pituitary adenomas were operated on by endoscopic transsphenoidal approach from January 2016 to February 2020. We retrospectively described two cases of vasospasm following pituitary surgery from our institution. Objective: To describe two cases of delayed cerebral vasospasm following endoscopic transsphenoidal surgery and review previous literature. Results: Out of two patients, the Glasgow outcome score (GOS) of one patient was favorable and the other was unfavorable. Conclusion: CVS is rare after transsphenoidal pituitary surgery, which makes its predictability difficult. The clinician should maintain a high index of suspicion in patients with suprasellar extension of the tumor and postoperative hematoma in the tumor bed. Similarly, care should be taken in patients with a subarachnoid hemorrhage in basal cistern, intraoperative arachnoid breach, and postoperative meningitis.

Xanthogranulomatous Colloid Cyst in a 13-Year-Old Boy: A Case Report and Surgical Implications.

INTRODUCTION: Colloid cysts are relatively uncommon lesions in the pediatric population. The xanthogranulomatous (XG) variant is very rare with less than 30 reported cases. CASE REPORT: In this report, the patient was a 13-year-old boy who presented with transient episodes of headache with blurring of vision. His MRI brain showed a T2 hyperintense well-defined cystic lesion, with an eccentrically located T2 hypointense partially enhancing nodule, at the foramen of Monro. He underwent middle frontal gyrus transcortical, transchoroidal gross total excision of the cyst. The histopathology of the lesion revealed an XG colloid cyst. The patient recovered well from the procedure and was relieved of the symptoms. CONCLUSION: XG colloid cyst may present with altered radiological features compared to the normal variant. This can pose a diagnostic dilemma, and it is important to differentiate it from a craniopharyngioma or a parasitic cyst, as in our case. When considered preoperatively, surgeons should be conscious to review their surgical strategies. Stereotactic aspiration of the XG cyst should be avoided as contents are thicker and heterogeneous than the usual. The spillage of cyst contents should be prevented. Also, the XG cysts are likely to have a poor cyst-fornix or -choroid plexus interface due to inflammation limiting complete resection.

Surgical management of simultaneous supra- and infratentorial hemorrhages in a pediatric patient with multiple cavernomas.

Multiple intracranial cavernomas are rare and occur mostly in familial cases. Clinical presentation with simultaneous rupture of two or more lesions has only been reported in four cases to date. A 15-year-old boy presented with simultaneous right frontal and superior vermian hematomas with hydrocephalus. The patient underwent a ventriculoperitoneal shunt, and his magnetic resonance imaging (MRI) revealed multiple cavernomas with bleed in the above-mentioned locations. The patient underwent a midline suboccipital craniotomy and excision of the cavernoma. The supratentorial lesions were left in situ in lieu of small size, no history of seizures, mass effect, or other neurological deficits. The patient recovered well from surgery with significant improvement in truncal ataxia. He remained asymptomatic for supratentorial lesions at follow-up. Cavernomas should be considered as differential diagnoses in cases of multiple intraparenchymal hemorrhages, especially in pediatric patients. The surgical management should be rationalized based on the lesion location, the eloquence of the surrounding parenchyma, mass effect, and the risks of re-rupture. Due to the rarity of multiple simultaneous hemorrhages, the management of multiple cavernomas remains controversial. The patient's relatives can be screened with MRI to rule out the familial form of the disease. Strict clinical and radiological follow-up is a must in such patients.

Granular Cell Tumor and Spindle Cell Oncocytoma of the Pituitary Gland: Imaging and Intraoperative Cytology Diagnostic Dilemmas and Management Challenges.

BACKGROUND: Tumors arising from the posterior pituitary gland are rare and closely resemble pituitary adenoma in presentation and imaging. Most of them come as a histopathologic surprise. We have analyzed the posterior pituitary tumors managed in our institute and have discussed the dilemmas in imaging, challenges in intraoperative squash cytology, and surgical management. METHODS: We retrospectively reviewed our operative database of pituitary tumors over the past 10 years, which included five posterior pituitary tumors (three granular cell tumors [GCTs] and two spindle cell oncocytomas [SCOs]). Clinical, imaging, and endocrine characteristics; intraoperative details; histopathologic features; and postoperative outcomes were collected and analyzed. RESULTS: The mean age of the patients was 47 years. All patients presented with varying degrees of vision loss. Radiology revealed a sellar / suprasellar lesion with the pituitary gland seen separately in two of three GCTs, whereas a separate pituitary gland could not be identified in both the SCOs. Pituitary adenoma was a radiologic diagnosis in only two of five cases. Three patients underwent a transsphenoidal surgery, whereas two underwent surgery by the transcranial approach. Intraoperative cytology was challenging, though a possibility of posterior pituitary tumor was considered in three of four cases, whereas one was considered meningioma. All the tumors were very vascular and influenced the extent of resection. CONCLUSIONS: GCTs and SCOs are relatively uncommon tumors that are difficult to diagnose on preoperative imaging. Intraoperative squash cytology too can pose challenges. A preoperative suspicion can prepare the surgeon for surgery of these hypervascular tumors. The transcranial approach may be necessary in cases of uncertainty in imaging.