Limitations of outcome prediction based on interfractional volume changes of large (≥ 10cm3) brain metastases during fractionated gamma knife radiosurgery.

PURPOSE: This study investigated the interfractional volume changes of large (≥ 10 cm3) brain metastases (BMs) during fractionated gamma knife radiosurgery (FGKRS) to assess its predictive value for tumor control outcomes. METHODS: The patients who underwent FGKRS for large BMs between January 2017 and December 2022 in our center were reviewed. The interfractional volume change was defined as the disparity in tumor volume (TV) measured between the magnetic resonance images acquired on the first treatment day and those obtained after 2 or 3 fractions during the course of FGKRS. RESULTS: A total of 73 lesions in 70 patients with various primary pathologies were included. Over a median follow-up period of 11 months (range 1-77), the tumor control rate was 63%. Initial TV (cm3) was associated with progression free survival (PFS) and overall survival (OS) in both univariate and multivariate analyses (p = 0.01). Interfractional TV changes revealed an increase in 13 (17.8%) lesions, no change in 14 (19.2%) lesions, and a decrease in 46 (63.0%) lesions, with a mean volume reduction of 5% ± 0.12. Three cut-offs (5%, 10% and 15% volume decrement) were established and patients were divided into two groups based on each reference point. However, there were no significant differences in PFS and OS between the two groups, irrespective of the chosen cut-off value used. CONCLUSION: Interfractional volume changes of large BMs were not found to be associated with tumor control outcomes. Neither significant interfractional volume reduction nor significant volume increase necessarily predicts the tumor control, making early close monitoring essential after FGKRS.

Endoscopic transorbital approach for resection of mediobasal temporal lesions using an optic radiation-sparing strategy.

OBJECTIVE: The endoscopic transorbital approach (ETOA) has emerged as a promising minimally invasive technique for resection of lesions in the mediobasal temporal region (MTR) due to its potential to preserve the integrity of the optic radiation (OR). This study evaluated the safety and efficacy of ETOA using an OR-sparing surgical strategy for mediobasal temporal lesions. METHODS: A retrospective review was conducted of the medical records of 15 patients (7 females and 8 males) who underwent ETOA for lesions in the MTR between November 2017 and November 2022. Preoperative diffusion tensor imaging (DTI) tractography of the OR was utilized in all cases for surgical planning to visualize the spatial relations between the OR and the target mediobasal temporal lesion. RESULTS: The median age of the treated patients was 43 years (range 22-76 years), with a median follow-up duration of 12 months (range 6-35 months). Eleven lesions (73.3%) involved only the anterior segment of the MTR, while 4 lesions (26.7%) affected both the anterior and middle segments. Gross-total resection was achieved in 13 patients (86.7%) and subtotal resection in 2 (13.3%). The final pathologies included low-grade glioma (n = 5), cavernous malformation (n = 3), glioblastoma multiforme (n = 2), multinodular and vacuolating neuronal tumor (n = 1), pleomorphic xanthoastrocytoma (n = 1), anaplastic oligodendroglioma (n = 1), adenoid cystic carcinoma (n = 1), and metastatic renal cell carcinoma (n = 1). Postoperative neuro-ophthalmological examinations revealed that all patients maintained their previous visual function. Follow-up DTI tractography further confirmed the preservation of the preoperative ORs in the treated patients. No postoperative CSF leaks, infections, or cosmetic problems occurred in this series. CONCLUSIONS: The combined use of ETOA and OR tractography appears to be a feasible approach for resecting lesions involving the MTR, especially in the anterior segment. In the authors' experience, this surgical strategy enables maximal safe resection while minimizing the risk of postoperative visual dysfunction. Further studies with larger sample sizes are warranted to validate these findings and assess long-term outcomes.

Nomogram for radiation-induced lymphopenia in patients receiving intensity-modulated radiotherapy based-chemoradiation therapy for newly diagnosed glioblastoma: A multi-institutional study.

Purpose: Severe lymphopenia (SLP) has emerged as a significant prognostic factor in glioblastoma. Intensity-modulated radiation therapy (IMRT)-based radiation therapy (RT) is suggested to minimize the risk of SLP. This study aimed to evaluate SLP incidence based on multi-institutional database in patients with GBM treated with IMRT and develop a predictive nomogram. Patients and methods: This retrospective study reviewed data from 348 patients treated with IMRT-based concurrent chemoradiation therapy (CCRT) at two major hospitals from 2016 to 2021. After multivariate regression analysis, a nomogram was developed and internally validated to predict SLP risk. Results: During treatment course, 21.0% of patients developed SLP and SLP was associated with poor overall survival outcomes in patients with GBM. A newly developed nomogram, incorporating gender, pre-CCRT absolute lymphocyte count, and brain mean dose, demonstrated fair predictive accuracy (AUC 0.723). Conclusions: This study provides the first nomogram for predicting SLP in patients with GBM treated with IMRT-based CCRT, with acceptable predictive accuracy. The findings underscore the need for dose optimization and radiation planning to minimize SLP risk. Further external validation is crucial for adopting this nomogram in clinical practice.

Phase II Efficacy and Safety of 80 mg Osimertinib in Patients With Leptomeningeal Metastases Associated With Epidermal Growth Factor Receptor Mutation-Positive Non-Small Cell Lung Cancer (BLOSSOM).

PURPOSE: Leptomeningeal metastases (LMs) exhibit a high incidence in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) post-treatment with first- or second-generation EGFR tyrosine kinase inhibitors (TKIs). This investigation evaluates the efficacy, safety, and pharmacokinetics of 80 mg once daily osimertinib in patients with LMs resistant to prior first- or second-generation EGFR TKIs. MATERIALS AND METHODS: In this phase II multicenter, open-label, single-arm study, 80 mg osimertinib was administered to patients with EGFR-mutated NSCLC who had developed LMs subsequent to treatment with prior EGFR TKIs. The primary end point was overall survival (OS), assessed alongside objective response rate by the blinded independent central review (BICR) and a pharmacokinetic analysis of plasma and cerebrospinal fluid (CSF) on the first day of cycles 3 and 6. RESULTS: A total of 73 patients diagnosed with LM were treated with osimertinib, including 64 patients evaluable for the LM efficacy set-T790M negative (n = 62) and T790M positive (n = 2). The median OS in the full-analysis set was 15.6 months (95% CI, 11.5 to 20.2). The objective response rate for LM was 51.6%, including a 15.6% complete response, and the disease control rate was 81.3% by BICR in the LM efficacy evaluable set. The median LM progression-free survival by BICR was 11.2 months (95% CI, 7.7 to 15.3), the duration of response was 12.6 months (95% CI, 7.6 to 17.7), and OS was 15.0 months (95% CI, 11.3 to 18.7). Pharmacokinetic analysis showed that the CSF to free plasma osimertinib ratio was 22%. Most safety profiles were grade 1 and 2. CONCLUSION: The study demonstrates significant intracranial efficacy and survival benefits of 80 mg once daily osimertinib in NSCLC patients with LMs. The data support considering daily 80 mg of osimertinib as a treatment option for EGFR-mutated NSCLC patients with LMs, irrespective of T790M mutation status.

Preclinical and dose-ranging assessment of hESC-derived dopaminergic progenitors for a clinical trial on Parkinson's disease.

Human embryonic stem cell (hESC)-derived midbrain dopaminergic (mDA) cell transplantation is a promising therapeutic strategy for Parkinson's disease (PD). Here, we present the derivation of high-purity mDA progenitors from clinical-grade hESCs on a large scale under rigorous good manufacturing practice (GMP) conditions. We also assessed the toxicity, biodistribution, and tumorigenicity of these cells in immunodeficient rats in good laboratory practice (GLP)-compliant facilities. Various doses of mDA progenitors were transplanted into hemi-parkinsonian rats, and a significant dose-dependent behavioral improvement was observed with a minimal effective dose range of 5,000-10,000 mDA progenitor cells. These results provided insights into determining a low cell dosage (3.15 million cells) for human clinical trials. Based on these results, approval for a phase 1/2a clinical trial for PD cell therapy was obtained from the Ministry of Food and Drug Safety in Korea, and a clinical trial for treating patients with PD has commenced.

Impact of boost sequence in concurrent chemo-radiotherapy on newly diagnosed IDH-wildtype glioblastoma multiforme.

BACKGROUND: The standard of care for glioblastoma multiforme (GBM) is maximal surgical resection followed by conventional fractionated concurrent chemoradiotherapy (CCRT) with a total dose of 60 Gy. However, there is currently no consensus on the optimal boost technique for CCRT in GBM. METHODS: We conducted a retrospective review of 398 patients treated with CCRT between 2016 and 2021, using data from two institutional databases. Patients were divided into two groups: those receiving sequential boost (SEB, N = 119) and those receiving simultaneous integrated boost (SIB, N = 279). The primary endpoint was overall survival (OS). To minimize differences between the SIB and SEB groups, we conducted propensity score matching (PSM) analysis. RESULTS: The median follow-up period was 18.6 months. Before PSM, SEB showed better OS compared to SIB (2-year, 55.6% vs. 44.5%, p = 0.014). However, after PSM, there was no significant difference between two groups (2-year, 55.6% vs. 51.5%, p = 0.300). The boost sequence was not associated with inferior OS before and after PSM (all p-values > 0.05). Additionally, the rates of symptomatic pseudo-progression were similar between the two groups (odds ratio: 1.75, p = 0.055). CONCLUSIONS: This study found no significant difference in OS between SEB and SIB for GBM patients treated with CCRT. Further research is needed to validate these findings and to determine the optimal boost techniques for this patient population.

Pharmacogenomic profiling reveals molecular features of chemotherapy resistance in IDH wild-type primary glioblastoma.

BACKGROUND: Although temozolomide (TMZ) has been used as a standard adjuvant chemotherapeutic agent for primary glioblastoma (GBM), treating isocitrate dehydrogenase wild-type (IDH-wt) cases remains challenging due to intrinsic and acquired drug resistance. Therefore, elucidation of the molecular mechanisms of TMZ resistance is critical for its precision application. METHODS: We stratified 69 primary IDH-wt GBM patients into TMZ-resistant (n = 29) and sensitive (n = 40) groups, using TMZ screening of the corresponding patient-derived glioma stem-like cells (GSCs). Genomic and transcriptomic features were then examined to identify TMZ-associated molecular alterations. Subsequently, we developed a machine learning (ML) model to predict TMZ response from combined signatures. Moreover, TMZ response in multisector samples (52 tumor sectors from 18 cases) was evaluated to validate findings and investigate the impact of intra-tumoral heterogeneity on TMZ efficacy. RESULTS: In vitro TMZ sensitivity of patient-derived GSCs classified patients into groups with different survival outcomes (P = 1.12e-4 for progression-free survival (PFS) and 3.63e-4 for overall survival (OS)). Moreover, we found that elevated gene expression of EGR4, PAPPA, LRRC3, and ANXA3 was associated to intrinsic TMZ resistance. In addition, other features such as 5-aminolevulinic acid negative, mesenchymal/proneural expression subtypes, and hypermutation phenomena were prone to promote TMZ resistance. In contrast, concurrent copy-number-alteration in PTEN, EGFR, and CDKN2A/B was more frequent in TMZ-sensitive samples (Fisher's exact P = 0.0102), subsequently consolidated by multi-sector sequencing analyses. Integrating all features, we trained a ML tool to segregate TMZ-resistant and sensitive groups. Notably, our method segregated IDH-wt GBM patients from The Cancer Genome Atlas (TCGA) into two groups with divergent survival outcomes (P = 4.58e-4 for PFS and 3.66e-4 for OS). Furthermore, we showed a highly heterogeneous TMZ-response pattern within each GBM patient using in vitro TMZ screening and genomic characterization of multisector GSCs. Lastly, the prediction model that evaluates the TMZ efficacy for primary IDH-wt GBMs was developed into a webserver for public usage ( http://www.wang-lab-hkust.com:3838/TMZEP ). CONCLUSIONS: We identified molecular characteristics associated to TMZ sensitivity, and illustrate the potential clinical value of a ML model trained from pharmacogenomic profiling of patient-derived GSC against IDH-wt GBMs.

Effect of Bevacizumab Treatment in Cerebral Radiation Necrosis : Investigation of Response Predictors in a Single-Center Experience.

OBJECTIVE: Bevacizumab is a feasible option for treating cerebral radiation necrosis (RN). We investigated the clinical outcome of RN after treatment with bevacizumab and factors related to the initial response and the sustained effect. METHODS: Clinical data of 45 patients treated for symptomatic RN between September 2019 and February 2021 were retrospectively collected. Bevacizumab (7.5 mg/kg) was administered at 3-week intervals with a maximum four-cycle schedule. Changes in the lesions magnetic resonance image (MRI) scans were examined for the response evaluation. The subgroup analysis was performed based on the initial response and the long-term maintenance of the effect. RESULTS: Of the 45 patients, 36 patients (80.0%) showed an initial response, and eight patients (17.8%) showed delayed worsening of the corresponding lesion. The non-responders showed a significantly higher incidence of diffusion restriction on MRI than the responders (100.0% vs. 25.0%, p<0.001). The delayed worsening group showed a significantly higher proportion of glioma pathology than the maintenance group (87.5% vs. 28.6%, p=0.005). Cumulative survival rates with sustained effect were significantly higher in the groups with non-glioma pathology (p=0.019) and the absence of diffusion restriction (p<0.001). Pathology of glioma and diffusion restriction in MRI were the independent risk factors for non-response or delayed worsening after initial response. CONCLUSION: The initial response of RN to bevacizumab was favorable, with improvement in four-fifths of the patients. However, a certain proportion of patients showed non-responsiveness or delayed exacerbations. Bevacizumab may be more effective in treating RN in patients with non-glioma pathology and without diffusion restriction in the MRI.

Clinical Outcomes of Moderately Hypofractionated Concurrent Chemoradiotherapy for Newly Diagnosed Glioblastoma.

PURPOSE: Hypofractionated radiotherapy (HypoRT) has recently been implemented in patients with glioblastoma (GBM) receiving concurrent temozolomide. Lymphopenia during treatment (LDT) is considered an important prognostic factor of clinical outcomes for GBM. We aimed to investigate the outcomes of HypoRT. MATERIALS AND METHODS: Among 223 patients with GBM, 145 and 78 were treated with conventionally fractionated RT (ConvRT, 60 Gy in 30 fractions) and HypoRT (58.5 Gy in 25 fractions), respectively. To balance characteristics between the two groups, propensity score matching (PSM) was performed. RESULTS: Patients in the HypoRT group were older and had smaller tumors than those in the ConvRT group (p<0.05). Furthermore, dose distributions to the brain were significantly lower in HypoRT than in ConvRT (p<0.001). Changes in absolute lymphocyte counts (ALC) during treatment were significantly lower after HypoRT than after ConvRT (p=0.018). With a median follow-up of 16.9 months, HypoRT showed comparable progression-free survival (9.9 months vs. 10.5 months) and overall survival (27.2 months vs. 26.6 months) to ConvRT (all p>0.05). Multivariable analysis before PSM revealed that ≥grade 2 LDT at 6 months was associated with inferior outcomes. Subsequent analysis demonstrated that HypoRT significantly reduced the rate of ≥grade 2 LDT at 6 months post-RT before and after PSM. CONCLUSION: HypoRT with 58.5 Gy in 25 fractions could provide comparable oncologic outcomes and significantly reduce the ALC changes. In addition, HypoRT decreased the LDT. Further investigation should be warranted to suggest the significance of reduced LDT through HypoRT affecting survival outcomes.

Impact of Postural Changes on Sinonasal Pressure After Endoscopic Endonasal Surgery.

BACKGROUND: Postoperative management following endoscopic endonasal surgery (EES) is important to prevent cerebrospinal fluid leak and preserve the integrity of the nasoseptal flap. No consensus regarding an optimal posture in the postoperative period has been established. We hypothesized that sinonasal pressure (SNP) can represent intracranial pressure affecting the sellar floor in the absence of the sellar bone after surgery. This study provides evidence for the effect of postural changes and recommends optimal posture to reduce SNP following EES. METHODS: The authors conducted a retrospective analysis of 50 patients who underwent reconstruction for skull base defects with nasoseptal flap after EES for resection of suprasellar tumor between March 2020 and August 2020. The Spiegelberg intracranial pressure probe was placed through the nostril over the nasoseptal flap. SNPs were measured in Fowler' (45° tilt) and supine positions, respectively, daily for the first 3 days immediately after EES. RESULTS: For the first 3 days after surgery, the mean SNP in Fowler' position (24.82 mmHg; standard deviation, 12.23 mmHg) was lower than that in the supine position (28.42 mmHg; standard deviation, 12.33 mmHg) (P < 0.01). There were no significant differences in mean SNP for age, sex, tumor size, presence of hydrocephalus, and body mass index. CONCLUSIONS: There was a significant correlation between Fowler' position and a decrease in SNP measurements. Placing a patient in Fowler' position after surgery can decrease the SNP. We recommend that patients should be placed in a Fowler' position as an optimal position after surgery.

Treatment Outcomes after Dose-Escalated Moderately Hypofractionated Radiotherapy for Frail Patients with High-Grade Glioma.

For high-grade glioma (HGG) patients with old age or poor performance status, hypofractionated radiotherapy (hypoRT) in 10-15 fractions is recommended. Also, limited data exist on the impact of salvage treatment after progression in frail patients. We retrospectively analyzed the outcomes of dose-escalated hypoRT in 40 frail HGG patients who were treated with hypoRT between 2013 and 2021. With a median biologically effective dose of 71.7 Gy, a total dose of 56 Gy in 20 fractions was the most frequently used regimen (53.7%). The median age and Karnofsky Performance Status of patients were 74 years and 70, respectively. Most patients (n = 31, 77.5%) were diagnosed with glioblastoma, IDH-wildtype, CNS WHO grade 4. Only 10 (25.0%) patients underwent surgical resection, and 28 (70.0%) patients received concurrent temozolomide during hypoRT. With a median follow-up of 9.7 months, the median overall survival (OS) was 12.2 months. Of the 30 (75.0%) patients with disease progression, only 12 patients received salvage treatment. The OS after progression differed significantly depending on salvage treatment (median OS, 9.6 vs. 4.6 months, p = 0.032). Dose-escalated hypoRT in 20 fractions produced survival outcomes outperforming historical data for frail patients.

IntraBrain Injector (IBI): A Stereotactic-Guided Device for Repeated Delivery of Therapeutic Agents Into the Brain Parenchyma.

BACKGROUND: To deliver therapeutics into the brain, it is imperative to overcome the issue of the blood-brain-barrier (BBB). One of the ways to circumvent the BBB is to administer therapeutics directly into the brain parenchyma. To enhance the treatment efficacy for chronic neurodegenerative disorders, repeated administration to the target location is required. However, this increases the number of operations that must be performed. In this study, we developed the IntraBrain Injector (IBI), a new implantable device to repeatedly deliver therapeutics into the brain parenchyma. METHODS: We designed and fabricated IBI with medical grade materials, and evaluated the efficacy and safety of IBI in 9 beagles. The trajectory of IBI to the hippocampus was simulated prior to surgery and the device was implanted using 3D-printed adaptor and surgical guides. Ferumoxytol-labeled mesenchymal stem cells (MSCs) were injected into the hippocampus via IBI, and magnetic resonance images were taken before and after the administration to analyze the accuracy of repeated injection. RESULTS: We compared the planned vs. insertion trajectory of IBI to the hippocampus. With a similarity of 0.990 ± 0.001 (mean ± standard deviation), precise targeting of IBI was confirmed by comparing planned vs. insertion trajectories of IBI. Multiple administrations of ferumoxytol-labeled MSCs into the hippocampus using IBI were both feasible and successful (success rate of 76.7%). Safety of initial IBI implantation, repeated administration of therapeutics, and long-term implantation have all been evaluated in this study. CONCLUSION: Precise and repeated delivery of therapeutics into the brain parenchyma can be done without performing additional surgeries via IBI implantation.

Gamma Knife Radiosurgery for Trigeminal Neuralgia : Review and Update.

Accurate diagnosis of trigeminal neuralgia (TN) is the starting point for optimal treatment. Gamma knife radiosurgery (GKRS) is currently regarded as one of the first-line treatment options for medically refractory TN. GKRS is a less invasive treatment with a low risk of complications than other surgical procedures that provides a favorable pain control (BNI I-IIIb) rate of >75% at short-term follow-up. Drawbacks of GKRS include the latency period before pain relief and higher recurrence rate compared with microvascular decompression. Therefore, repeat treatment is necessary if the initial GKRS was effective but followed by recurrence. The concept of dose rate and the biologically effective dose of radiation has been actively studied in radiation oncology and is also applied in GKRS for TN to achieve high safety and efficacy by prescribing the optimal dose. Recent progress in functional imaging, such as diffusion tensor imaging, enables us to understand the pathophysiology of TN and predict the clinical outcome after GKRS. Here, we review TN, GKRS, and recent updates, especially in the concepts of radiation dose, diffusion tensor imaging studies, and repeat treatment in GKRS for TN.

Clinical outcomes of patients with multiple courses of radiosurgery for brain metastases from non-small cell lung cancer.

We investigated the long-term clinical outcomes of patients who underwent multiple courses (≥ 5) of gamma knife radiosurgery (GKRS) due to recurrent brain metastases (BM) from non-small cell lung cancer (NSCLC). Between December 2001 and July 2019, consecutive 2571 patients underwent GKRS for BM from NSCLC. Clinical and radiological outcomes were investigated in 76 patients who underwent GKRS ≥ 5 times. The median follow-up period after the diagnosis of NSCLC was 54.6 months (range 14.5-159.1 months). The median number of GKRS procedures per patient was six (range 5-15). Actuarial post-GKRS survival rates at 1, 2, 3, 4, and 5 years following initial GKRS were 88.1%, 79.5%, 65.3%, 51.4%, and 37.3%, respectively. No significant difference in overall survival was observed between patients (n = 22) with whole-brain radiotherapy (WBRT) and patients (n = 54) without WBRT (p = 0.076). The incidence of radiation-induced leukoencephalopathy was 64% and 18% in patients with and without WBRT, respectively (p < 0.0001). Multiple courses of SRS are a tolerable and effective treatment option for recurrent BM from NSCLC. Repeat SRS may be an alternative treatment option to avoid or delay WBRT.

Clinical Impact of Hydroxyapatite on the Outcome of Skull Base Reconstruction for Intraoperative High-Flow CSF Leak: A Propensity Score Matching Analysis.

Background: Despite recent advances in skull base reconstructive techniques, including the multilayer technique during the last decade, complete reconstruction of grade 3 intraoperative high-flow cerebrospinal fluid (CSF) leak remains challenging. This study was designed to investigate the role of injectable hydroxyapatite (HXA) used in the multilayer technique on the clinical outcome of skull base reconstruction for intraoperative high-flow CSF leak. Materials and Methods: This study enrolled 187 patients who experienced intraoperative high-flow CSF leak after endoscopic endonasal surgery for anterior skull base or suprasellar pathologies between January 2014 and July 2021. All skull base defects were reconstructed using the conventional multilayer technique including a vascularized naso-septal flap (NSF, n = 141) and the combined use of HXA with the conventional multilayer technique (HXA group, n = 46). We retrospectively evaluated the efficacy of the HXA group by 1:2 propensity score matching analysis. Results: Overall, 17 of 187 patients (9.1%) showed postoperative CSF leaks, resulting in second reconstruction surgery. There were no statistical differences in patient age, sex, body mass index, tumor location, tumor type, and degree of resection, except for the follow-up period between the two groups. The HXA group showed a significantly lower incidence of postoperative CSF leak than the control group (0% vs. 12.1%, p < 0.05). Postoperative lumbar drain (LD) was performed in 8.7% of the HXA group compared to 46.1% of the control group (p < 0.01). CSF leak-related infection rates showed a decreasing tendency in the HXA group compared to the control group (0 vs. 7.1%, p = 0.06). A total of 46 patients in the HXA group were well matched with the control group (92 patients) at a 1:2 ratio. In the propensity score-matched control group, there were higher rates of postoperative CSF leaks than in the HXA group. Conclusion: The use of HXA combined with the conventional multilayer technique completely reduced postoperative CSF leaks in this study. This technique resulted in reduced CSF leakage, even without postoperative LD, and decreased infection rates. Further randomized comparative studies are required to confirm our findings.

Combined endoscopic endonasal and transorbital multiportal approach for complex skull base lesions involving multiple compartments.

PURPOSE: This study defines the specific areas that connect the surgical corridors of the endoscopic endonasal (EEA) and transorbital approach (TOA) to identify adequate clinical applications and perspectives of this combined multiportal approach. METHODS: Consecutive patients who underwent combined EEA and TOA procedures for various pathologies involving multiple compartments of the skull base were enrolled. RESULTS: A total of eight patients (2 chondrosarcomas, 2 meningiomas, 2 schwannomas, 1 glioma, and 1 traumatic optic neuropathy) were included between August 2016 and April 2021. The cavernous sinus (CS) was targeted as the connection area of the combined approach in four patients with tumors infiltrating the middle cranial fossa (MCF) and central skull base through the CS. For two patients with MCF tumors extending into the infratemporal fossa (ITF), the horizontal portion of the greater sphenoid wing and the foramen ovale were utilized as the connection area. In the remaining 2 patients, connection was achieved through the optic canal (OC). Gross total and near total resection was achieved in 5 patients with tumors, and circumferential removal of bone composing the OC was performed in one patient with traumatic compressive optic neuropathy. Postoperative complications included one cardiac arrest due to underlying cardiovascular disease and one case of oculomotor nerve palsy. CONCLUSIONS: The combined EEA and TOA procedure is a useful strategy for complex lesions involving multiple compartments of the skull base. Herein, we identified the specific areas connecting the two surgical approaches, allowing a common path for EEA and TOA procedures.

Factors Associated with Acute Obstructive Hydrocephalus After Retrosigmoid Approach for Extra-Axial Cerebellopontine Angle Tumors.

BACKGROUND: This study aimed to identify the risk factors for acute obstructive hydrocephalus (AOHCP) after extra-axial cerebellopontine angle (CPA) tumor surgery using the retrosigmoid (RS) approach. METHODS: This retrospective study assessed 154 patients (100 vestibular schwannomas, 34 CPA meningiomas [MNGs], 9 trigeminal schwannomas, and 11 petroclival MNGs) who underwent surgical resection using the RS approach by a single surgeon between August 2010 and September 2019. AOHCP was defined as postoperative ventricular enlargement due to cerebrospinal fluid flow obstruction caused by surgery-related cerebellar injury within 1 week. The radiological characteristics of the tumors were classified, and the surgical outcomes were reviewed. We analyzed the impact of different factors on the development of AOHCP after surgery. RESULTS: AOHCP developed in 17 (11%) patients, all of whom were treated with external ventricular drain insertion. Multivariate analysis showed that CPA MNGs (odds ratio [OR], 37.98), grade of tumor extension beyond the petroclival junction (grade 1: OR, 16.42; grade 2: OR, 17.47), major fourth ventricle compression (OR, 17.77), and surgery-related hemorrhage (OR, 7.64) were associated with AOHCP. Surgery-related hemorrhage was observed in 17 (11%) patients. 9 (6%) patients underwent ventriculoperitoneal shunt surgery because of persistent HCP. CONCLUSIONS: An increased risk of AOHCP after the RS approach was observed in patients with extra-axial CPA tumors with clival extension and major fourth ventricle compression. Compulsive and meticulous hemostasis must be achieved because postoperative hemorrhage is associated with AOHCP.

Histopathology and surgical outcome of symptomatic treatment-related changes after gamma knife radiosurgery in patients with brain metastases.

A late-onset treatment-related changes (TRCs), which represent radiographic radiation necrosis (RN), frequently occur after stereotactic radiosurgery (SRS) for brain metastases and often need surgical treatment. This study aimed to validate the true pathology and investigate clinical implication of surgically resected TRCs on advanced magnetic resonance imaging (MRI). Retrospective analyses of 86 patients who underwent surgical resection after radiosurgery of brain metastases were performed. Fifty-four patients displayed TRCs on preoperative MRI, comprising pure RN in 19 patients (TRC-RN group) and mixed viable tumor cells in 35 patients (TRC-PD group). Thirty-two patients revealed the consistent diagnosis of progressive disease in both MRI and histopathology (PD-PD group). The TRC-PD group showed larger prescription isodose volume (9.4 cm3) than the TRC-RN (4.06 cm3, p = 0.014) group and a shorter time interval from SRS to preoperative MRI diagnosis (median 4.07 months) than the PD-PD group (median 8.77 months, p = 0.004). Progression-free survival was significantly different among the three groups (p < 0.001), but not between TRC-RN and TRC-PD (post hoc test, p = 1.00), while no difference was observed in overall survival (p = 0.067). Brain metastases featured as TRCs after SRS frequently contained viable tumor cells. However, this histologic heterogeneity had a minor impact on benign local prognosis of TRCs after surgical resection.