Ki-67 labeling index predicts tumor progression patterns and survival in patients with atypical meningiomas following stereotactic radiosurgery.

PURPOSE: This study investigated whether Ki-67 labeling index (LI) correlated with clinical outcomes after SRS for atypical meningiomas. METHODS: This retrospective study examined 39 patients with atypical meningiomas who underwent SRS over a 10-year study period. Ki-67 LI was categorized into 3 groups: low (< 5%), intermediate (5%-10%), and high (> 10%). Local tumor control rates (LCRs), progression-free rates (PFRs), disease-specific survival (DSS) rates, and adverse radiation-induced events (AREs) were evaluated. RESULTS: The median follow-up periods were 26 months. SRS was performed at a median prescription dose of 18 Gy for tumors with a median Ki-67 LI of 9.6%. The 3-year LCRs were 100%, 74%, and 25% in the low, intermediate, and high LI groups, respectively (p = 0.011). The 3-year PFRs were 100%, 40%, and 0% in the low, intermediate, and high LI groups (p = 0.003). The 5-year DSS rates were 100%, 89%, and 50% in the low, intermediate, and high LI groups (p = 0.019). Multivariable Cox proportional hazard analysis showed a significant correlation of high LI with lower LCR (hazard ratio [HR], 3.92; 95% confidence interval [CI] 1.18-13.04, p = 0.026), lower PFR (HR 3.80; 95% CI 1.46-9.88, p = 0.006), and shorter DSS (HR 6.55; 95% CI 1.19-35.95, p = 0.031) compared with intermediate LI. The ARE rates were minimal (8%) in the entire group. CONCLUSION: Patients with high Ki-67 LI showed significantly more tumor progression and tumor-related death. Ki-67 LI might offer valuable predictive insights for the post-SRS management of atypical meningiomas.

Long-term outcomes of stereotactic radiosurgery for intracranial schwannoma in neurofibromatosis type 2: a genetic analysis perspective.

PURPOSE: Neurofibromatosis type 2 (NF2) is intractable because of multiple tumors involving the nervous system and is clinically diverse and genotype-dependent. Stereotactic radiosurgery (SRS) for NF2-associated schwannomas remains controversial. We aimed to investigate the association between radiosurgical outcomes and mutation types in NF2-associated schwannomas. METHODS: This single-institute retrospective study included consecutive NF2 patients with intracranial schwannomas treated with SRS. The patients' types of germline mutations ("Truncating," "Large deletion," "Splice site," "Missense," and "Mosaic") and Halliday's genetic severity scores were examined, and the associations with progression-free rate (PFR) and overall survival (OS) were analyzed. RESULTS: The study enrolled 14 patients with NF2 with 22 associated intracranial schwannomas (median follow-up, 102 months).　The PFRs in the entire cohort were 95% at 5 years and 90% at 10-20 years. The PFRs tended to be worse in patients with truncating mutation exons 2-13 than in those with other mutation types (91% at 5 years and 82% at 10-20 years vs. 100% at 10-20 years, P = 0.140). The OSs were 89% for patients aged 40 years and 74% for those aged 60 years in the entire cohort and significantly lower in genetic severity group 3 than in the other groups (100% vs. 50% for those aged 35 years; P = 0.016). CONCLUSION: SRS achieved excellent PFR for NF2-associated intracranial schwannomas in the mild (group 2A) and moderate (group 2B) groups. SRS necessitates careful consideration for the severe group (group 3), especially in cases with NF2 truncating mutation exons 2-13.

Safety evaluation of sinus patency after stereotactic radiosurgery for transverse-sigmoid sinus dural arteriovenous fistulas: implications of treatment options for patients with Borden type I fistulas.

OBJECTIVE: This study aimed to assess the efficacy and safety of stereotactic radiosurgery (SRS) in treating transverse-sigmoid sinus dural arteriovenous fistulas (TSS DAVFs), and to investigate post-SRS sinus patency, focusing on the risk factors associated with treated sinus occlusion. METHODS: Data from 34 patients treated with SRS between January 2006 and April 2023 were analyzed. Detailed angioarchitecture was confirmed using digital subtraction angiography before SRS. Angiography of the ipsilateral internal carotid artery and vertebral artery was performed to evaluate whether the involved side of the TSS was used for normal venous drainage. TSS stenosis was defined as sinus diameter < 50% of the normal proximal diameter. DAVF shunt obliteration, TSS occlusion, neurological status, and adverse events were also evaluated. RESULTS: Of the 34 patients, 21 had Borden type I and 14 had Borden type II DAVFs. The median age at SRS was 64 years (interquartile range 54-71 years), and the follow-up period was 31 months (interquartile range 15-94 months). Complete shunt obliteration was achieved in 24 (70.6%) patients. The cumulative 2-, 3-, and 5-year shunt obliteration rates were 49.6%, 71.2%, and 86.0%, respectively. Borden type I had higher obliteration rates (60.5%, 83.1%, and 94.4%, respectively) than Borden type II (41.7%, 51.4%, and 75.7%, respectively; p = 0.034). TSS occlusion occurred in 5 patients (14.7%). The cumulative 1-, 5-, and 10-year TSS occlusion rates were 2.9%, 8.3%, and 23.6%, respectively, across the entire cohort. All occlusions occurred exclusively in the sinuses that were not used for normal venous drainage. Cox proportional analyses revealed that TSS stenosis and the sinus not being used for normal venous drainage were significantly associated with a greater risk of TSS occlusion after SRS (HR 9.44, 95% CI 1.01-77.13; p = 0.049). CONCLUSIONS: SRS is effective and safe for TSS DAVF and results in favorable shunt obliteration, symptom improvement, and low complication rates. TSS occlusion after SRS is asymptomatic and is limited to sinuses that are not used for normal venous drainage.

Stereotactic radiosurgery for recurrent pleomorphic adenoma of the lacrimal gland: a case report.

Lacrimal gland pleomorphic adenomas (LGPAs) are common, benign, and intraorbital tumours that cause exophthalmos, ptosis, and visual disturbances. The curative treatment for LGPAs is gross total resection, and radiotherapy is considered adjunctive for recurrence or an alternative for inoperable LGPAs. Stereotactic radiosurgery (SRS) can be used for precise delivery of high radiation doses to the tumour, crucial in the treatment of intra-and extracranial neoplasms. Here, we present a 95-year-old woman who had a rapidly growing, recurrent LGPA and was successfully treated with SRS. The tumour was controlled without any adverse events over 21 months following SRS. SRS is a potential alternative treatment for recurrent LGPA.

[Radiotherapy for Pituitary Tumors:An Overview of the Current Evidence].

Various tumors, such as pituitary neuroendocrine tumors(PitNETs)and craniopharyngiomas, can arise in the sellar/parasellar region. Although surgical removal is the standard therapeutic modality for these pathologies, a single surgery may not be sufficient to provide durable tumor control, given the surrounding critical neurovascular structures. Therefore, adjunctive radiotherapy has a substantial role in treating these neoplasms. There are wide variety of radiotherapy modalities, including photon-based fractionated radiotherapy, stereotactic radiosurgery/radiotherapy, and proton- and carbon-ion beam-based radiotherapies. All modalities have their own advantages and disadvantages and thus need to be selectively used after consideration of their characteristics and existing evidence. In addition, the radiation sensitivity of normal anatomies should be kept in mind. In particular, the optic apparatus is very sensitive to ionizing radiation; thus, meticulous care needs to be taken when creating a radiation plan to avoid optic neuropathy. Overall, if properly used, radiotherapy can provide excellent durable tumor control for PitNETs, craniopharyngiomas, and even chordomas. A judicious combination of surgery and radiotherapy plays a key role in functional preservation without affecting tumor control or overall survival.

Long-term outcomes of stereotactic radiosurgery for skull base tumors involving the cavernous sinus.

PURPOSE: Stereotactic radiosurgery (SRS) is an effective and less invasive therapeutic option for cavernous sinus (CS) tumors. However, its long-term effectiveness and neurological outcomes have yet to be fully elucidated. We aimed to examine the long-term outcomes of SRS for CS tumors. METHODS: Overall, a cohort of 113 patients with benign CS tumors, including 91 with meningioma, 14 with trigeminal schwannoma (TS), and eight with cavernous hemangioma, treated with SRS at our institution from 1990 to 2018, was included. Tumor control and functional preservation/recovery were evaluated in detail. RESULTS: The median post-SRS follow-up period was 77 months (interquartile range, 39-177). Progression-free survival (PFS) was 97% at 5 years, 89% at 10 years, and 87% at 15 years for the entire cohort; 96% at 5 years and 87% at 10 years for meningiomas; and 100% at 10 years for the other tumors. No significant difference was observed between meningiomas and non-meningiomas (log-rank test, p = 0.107). Improvement in cranial nerve (CN) function was observed in 35 (27%) patients. TSs tended to show CN improvements more often than meningiomas did (total improvements, 62% vs. 23%; p = 0.004; eye movement function, 100% vs. 20%; p = 0.002). CN deterioration or development of new CN deficits was observed in 11 (10%) patients. CONCLUSION: SRS provides good tumor control and acceptable long-term outcome with sufficient preservation of CN function in patients with benign CS tumors.

Stereotactic radiosurgery ensures an effective and safe long-term control of Koos grade IV vestibular schwannomas: a single-center, retrospective, cohort study.

PURPOSE: Stereotactic radiosurgery (SRS) is a standard treatment modality for vestibular schwannomas (VSs). However, there is a paucity of data on tumor control and neurological preservation for larger VSs. We aimed to investigate the long-term effectiveness of SRS for Koos grade IV compared with I-III VSs. METHODS: We included 452 patients with VSs (50 Koos grade IV and 402 Koos grade I‒III) who were treated with SRS at our institution from 1990 to 2021. Tumor control and functional preservation were calculated using the Kaplan-Meier method and compared between groups with the log-rank test. RESULTS: The median post-SRS follow-up period was 68 months. Progression-free survival rates were 91% at 5 and 10 years for Koos grade IV VSs, and 95% and 92%, respectively, for Koos grade I‒III VSs (p = 0.278). In Koos grade IV VSs, functional preservation rates of the facial and trigeminal nerves were both 96% at 5 years (both 98% for Koos grade I‒III VSs; facial, p = 0.410; trigeminal, p = 0.107). Hearing preservation rates were 61% at 5 years for Koos grade IV VSs and 78% for Koos grade I-III VSs (p = 0.645). Symptomatic transient tumor expansion was more common with Koos grade IV VSs (8.0% vs. 2.5%, p = 0.034), although all related symptoms diminished in accordance with tumor shrinkage. CONCLUSION: SRS may contribute to long-term tumor control and adequate neurological preservation in the treatment of Koos grade IV VSs, comparable to those in the treatment of Koos grade I‒III VSs.

Revisitation of imaging features of skull base chondrosarcoma in comparison to chordoma.

PURPOSE: Pre-surgical diagnosis of skull base chondrosarcoma (SBC) is often challenging due to the resemblance to chordoma. The goal of this study was to develop an optimal method for predicting SBC diagnosis. METHODS: This retrospective study included patients with histologically diagnosed SBC and skull base chordoma. Their clinical and radiologic features were compared, and the predictive factors of SBC were examined. RESULTS: Forty-one patients with SBC and 41 with chordoma were included. Most SBCs exhibited hypointensity (25, 64.1%) or isointensity (12, 30.8%) on T1-weighted images, and hyperintensity (34, 87.1%) or mixed intensity (5, 12.8%) on T2-weighted images. MRI contrast enhancement was usually avid or fair (89.7%) with "arabesque"-like pattern (41.0%). The lateral/paramidline location was more common in SBC than in chordoma (85.4% vs. 9.8%; P < 0.01), while midline SBCs (14.6%) were also possible. Multivariate analysis demonstrated that higher apparent diffusion coefficient (ADC) value (unit odds ratio 1.01; 95% confidence interval 1.00-1.02; P < 0.01) was associated with an SBC diagnosis. An ADC value of ≥ 1750 × 10-6 mm2/s demonstrated a strong association with an SBC diagnosis (odds ratio 5.89 × 102; 95% confidence interval 51.0-6.80 × 103; P < 0.01) and yielded a sensitivity of 93.9%, specificity of 97.4%, positive predictive value of 96.9%, and negative predictive value of 95.0%. CONCLUSION: The ADC-based method is helpful in distinguishing SBC from chordoma and readily applicable in clinical practice. The prediction accuracy increases when other characteristics of SBC, such as non-midline location and arabesque-like enhancement, are considered together.

A multicenter, open-label, single-arm phase I trial of neoadjuvant nivolumab monotherapy for resectable gastric cancer.

BACKGROUND: Nivolumab monotherapy has demonstrated superior efficacy in advanced unresectable gastric cancer (GC), but its impact on resectable GC remains unknown. This phase I study aimed to evaluate safety, feasibility, and potential biomarkers of neoadjuvant nivolumab monotherapy in resectable GC. METHODS: Untreated, resectable, cT2 or more advanced gastric adenocarcinomas with clinical stage I, II, or III were treated with two doses of nivolumab before gastrectomy. Patients were excluded if their tumors may be applicable to neoadjuvant chemotherapy. The primary endpoint was the incidence of adverse event (AE) categories of special interest. RESULTS: All of the 31 enrolled patients completed 2 doses of nivolumab monotherapy. While 30 (97%) patients underwent surgery with curative intent, 1 patient discontinued before the planned surgical intervention because of a newly emerging liver metastasis. Seven patients (23%) had nivolumab treatment-related AEs, and one patient had a treatment-related AE of grade 3-4. The incidences of treatment-related AE categories of special interest ranged from 0 to 6%. Notable surgical complications included two cases of grade 3 anastomotic leakage and two cases of pancreatic fistula. The major pathologic response (MPR) assessed by the independent pathology review committee was achieved in five (16%) patients, of which one patient had a pathologic complete response. The MPR was mostly observed in patients with positive PD-L1 expression, high microsatellite instability, and/or high tumor mutation burden. CONCLUSIONS: Neoadjuvant nivolumab monotherapy is feasible with an acceptable safety profile and induces a MPR in certain patients with resectable GC. (Registration: clinicaltrials.jp, JapicCTI-183895).

Hemodynamic changes during the obliteration process for cerebral arteriovenous malformations after radiosurgery.

OBJECTIVE: The process of cerebral arteriovenous malformation (AVM) obliteration following radiosurgery is poorly understood. Authors of this retrospective study aimed to assess the changes in AVM hemodynamics after stereotactic radiosurgery (SRS) by using 3D flow magnetic resonance imaging (MRI) to elucidate the process of AVM obliteration. METHODS: Twenty-four patients with AVMs treated with SRS between July 2015 and December 2017 were included in this study and classified into two groups depending on the duration of AVM obliteration: group A, obliteration within 3 years (n = 15); and group B, obliteration taking more than 3 years or no obliteration (n = 9). Blood flow (ml/min) in the largest feeding artery was measured before and after SRS by using time-averaged 3D flow MRI. The decreasing rate of blood flow in the feeding artery after SRS was calculated as the percent change from baseline blood flow. A Wilcoxon rank-sum test was used to compare the decreasing blood flow rate between the two groups at 4 and 12 months after SRS. RESULTS: For the entire cohort, the mean decrease in blood flow in the feeding artery from baseline was 29% at 4 months and 71% at 12 months after SRS. In general, blood flow after SRS decreased faster in group A and slower in group B. The decreasing rates in blood flow at 4 and 12 months after SRS were significantly different between the two groups (p = 0.02 and < 0.001, respectively). CONCLUSIONS: Tracking changes in AVM hemodynamics after SRS may be useful for assessing the progress of AVM obliteration and the therapeutic effects of SRS, possibly contributing to the prediction of subsequent obliteration outcome.

[Surgical Site Infection Following Craniotomies].

Surgical site infections(SSIs)remain a significant complication of craniotomies, with a reported incidence ranging from 1% to 8%. SSIs are generally categorized as superficial, deep incisional, and organ/space SSIs. Computed tomography and/or magnetic resonance imaging are essential for determining the depth of infection. Lumbar puncture is also helpful for the diagnosis of meningitis; however, imaging studies should be performed prior lumbar puncture to minimize the risk of cerebral herniation. While superficial SSIs can be resolved with antibiotics, all deeper SSIs except meningitis generally require surgical interventions, including wound wash-out and debridement of necrotic tissues and artificial materials, followed by 6-8 weeks of medical treatment using broad-spectrum antibiotics. Administration of antibiotics may be deferred until the specimens are corrected to increase the detection rate of causative microorganisms. Various factors are known to be associated with SSIs; thus, evidence-based efforts should be made to decrease the incidence of SSIs.

Outcomes of stereotactic radiosurgery in young adults with vestibular schwannomas.

PURPOSE: Vestibular schwannomas (VSs) are comparatively rare in younger patients, and stereotactic radiosurgery (SRS) outcome data are limited. We aimed to evaluate long-term SRS outcomes concerning sporadic VSs in patients aged ≤ 40 years. METHODS: Of 383 patients with VS who had undergone SRS at our institution between 1990 and 2017, we retrospectively compared younger and older patients' tumor control and radiation-induced complication rates using case-control propensity score (PS) matching. RESULTS: The mean follow-up was 83 and 92 months in older and younger patients, respectively. Compared with older patients, younger patients were more likely to have a history of resection (20% vs. 39%, p = 0.006) and be treated with higher marginal doses (median, 12 Gy vs. 14 Gy; p = 0.014). Cumulative 5- and 10-year tumor control rates were higher in older patients (97.7% and 93.9%, respectively) than in younger patients (90.2% and 85.4%, respectively, p = 0.024). After PS matching, younger patients' cumulative tumor control rates (93.6%, 85.4%, and 85.4% at 5, 10, and 15 years, respectively) were similar to those of older patients (p = 0.411). No significant between-cohort differences in hearing preservation rates or other cranial nerve complications were observed. Two younger patients had malignant tumors several years post-SRS, with one patient having confirmed histological transformation. CONCLUSIONS: SRS is equally effective for younger and older patients. Complications other than hearing deterioration are uncommon. However, malignant transformation is possible, and long-term post-SRS surveillance MRI is important. These data are useful for decision-making involving young adults with VSs.

The role of single-fraction stereotactic radiosurgery for atypical meningiomas (WHO grade II): treatment results based on a 25-year experience.

PURPOSE: To clarify the role of stereotactic radiosurgery (SRS) for atypical meningiomas (AM). METHODS: A retrospective analysis of 68 patients with AM having SRS from 1995 until 2019. RESULTS: Nineteen patients (28%) had undergone prior external beam radiation therapy (EBRT) (median dose, 54 Gy). The median follow-up period was 52 months. Eighteen (26%), 17 (25%), and 33 (49%) patients received SRS as an upfront adjuvant (≤ 6 months), early salvage (7-18 months), or late salvage treatment (> 18 months), respectively. The 3-, 5-, and 10-year progression-free survivals (PFSs) were 52%, 35%, and 25%, respectively. The 3-, 5-, and 10-year disease-specific survivals were 85%, 78%, and 61%, respectively. Adverse radiation events (AREs) were observed in 12 patients (18%), with increased or new seizures being the most frequent complication (n = 7). Prior EBRT was associated with reduced PFS (HR 5.92, P < 0.01), reduced DSS (HR 5.84, P < 0.01), and an increased risk of ARE (HR 3.31, P = 0.04). Timing of SRS was correlated with reduced PFS for patients having early salvage treatment compared to upfront adjuvant (HR 3.17, P = 0.01) or late salvage treatment (HR 4.39, P < 0.01). CONCLUSION: PFS for patients with residual/recurrent AM remains poor despite SRS. Prior EBRT was associated with worse tumor control, higher tumor-related mortality, and an increased risk of ARE. Further study on the timing of SRS is needed to determine if upfront adjunctive SRS improves tumor control compared to salvage SRS.

Long-term outcomes of grade I/II skull base chondrosarcoma: an insight into the role of surgery and upfront radiotherapy.

PURPOSE: To clarify the need for post-operative radiation treatment in skull base chondrosarcomas (SBCs). METHODS: A retrospective analysis of patients with grade I or II SBC. Patients were divided according to post-surgical treatment strategies: (A) planned upfront radiotherapy and (B) watchful waiting. Tumor control and survival were compared between the treatment groups. The median follow-up after resection was 105 months (range, 9-376). RESULTS: Thirty-two patients (Grade 1, n = 16; Grade 2, n = 16) were included. The most frequent location was petroclival (21, 64%). A gross total resection (GTR) was achieved in 11 patients (34%). Fourteen (44%) underwent upfront radiotherapy (group A) whereas 18 (56%) were followed with serial MRI alone (group B). The tumor control rate for the entire group was 77% and 69% at 10- and 15-year, respectively. Upfront radiotherapy (P = 0.25), extent of resection (P = 0.11) or tumor grade (P = 0.83) did not affect tumor control. The majority of Group B patients with recurrent tumors (5/7) obtained tumor control with repeat resection (n = 2), salvage radiotherapy (n = 2), or a combination of both (n = 1). The 10-year disease-specific survival was 95% with no difference between the group A and B (P = 0.50). CONCLUSION: For patients with grade I/II SBC, a reasonable strategy is deferral of radiotherapy after maximum safe resection until tumor progression or recurrence. At that time, most patients can be successfully managed with salvage radiotherapy or surgery. Late recurrences may occur, and life-long follow-up is advisable.

Stereotactic radiosurgery as a primary treatment for metastatic skull base alveolar soft part sarcoma: a case report.

Alveolar soft part sarcoma (ASPS) is a rare malignancy that typically arises in the trunk or extremities and preferentially metastasises to the brain. Radical resection is generally recommended for cranial metastatic ASPS, but stereotactic radiosurgery (SRS) is a recognised alternative for tumours in surgically challenging locations. Here, we present the case of a 22-year-old female, who underwent SRS and systemic therapy with pazopanib for a metastatic ASPS in the left temporal bone. The tumour was successfully controlled without further intervention over 23 months following SRS, which should be considered for metastatic ASPS when surgical resection is not appropriate.

Tailored flow sequestration treatment using high-flow and low-flow bypass for partially thrombosed giant internal carotid artery aneurysm-a technical case report.

Direct clipping of giant partially thrombosed intracranial internal carotid artery (ICA) aneurysms is challenging, especially when important perforating arteries are involved. Proximal occlusion with bypass represents a possible alternative approach. An 80-year-old female presented with worsening visual acuity and severe headache caused by partially thrombosed giant (38 mm in diameter) aneurysms of the right ICA, suggestive of impending rupture. Direct clipping in conjunction with temporary occlusion of the lesion involving the anterior choroidal artery (AChA) was considered too risky. Thus, we sequestrated the ipsilateral ICA flow into a low-flow and a high-flow system using two external carotid artery (ECA)-ICA bypasses and one in situ bypass with cervical ICA ligation. As a result, the low-flow system by the superficial temporal artery-middle cerebral artery (MCA) bypass perfused mainly the proximal MCA lesions and aneurysm, whereas the high-flow system by ECA-radial artery-M2 bypass exclusively supplied the residual distal MCA area. This tailored flow sequestration successfully interrupted intra-aneurysmal flow and accelerated near-complete thrombosis of the aneurysm while preserving the AChA and avoiding any significant neurological deterioration. We conclude that this method is effective for the management of giant partially thrombosed aneurysms of the ICA, especially when direct clipping is difficult.

A3-A3 anastomosis and superficial temporal artery-radial artery graft-A3 bypass to treat bilateral ACA steno-occlusive hemodynamic ischemia with cognitive and executive dysfunction: a technical note.

BACKGROUND: Executive functions are complex cognitive control functions that include cognitive flexibility, inhibition (self-control, self-regulation), and working memory. Bilateral frontal lobe ischemia is associated with cognitive impairment, especially in the context of dysexecutive syndrome. This report describes two patients who underwent bilateral anterior cerebral artery (ACA) reconstruction by A3-A3 anastomosis in conjunction with superficial temporal artery (STA)-radial artery (RA) graft-A3 bypass to treat bilateral ACA steno-occlusive hemodynamic ischemia accompanying cognitive and executive dysfunction. METHOD: A 74-year-old woman and a 73-year-old woman were admitted to our hospital for unilateral cerebral infarction in the frontal lobe. Magnetic resonance angiogram (MRA) demonstrated severe bilateral ACA steno-occlusive pathology in both patients. Considering the presence of impaired cognitive function with dysexecutive syndrome as well as hemodynamic compromise shown by single photon emission computed tomography (SPECT), we proceeded with A3-A3 anastomosis in conjunction with STA-RA-A3 bypass. Various neuropsychiatric tests were performed before and after the surgery. RESULTS: We confirmed good bypass patency without periprocedural complications. One patient recovered from apallic and bedridden status and regained ambulatory condition and ability to take in an oral diet. Another patient demonstrated improved scores in several cognitive tests with some persistent executive dysfunction. CONCLUSIONS: Bilateral ACA revascularization was technically feasible in two patients. This bypass surgery could have some positive effects in some basic cognitive function, such as memory, attention, and concentration by bilateral ACA hemodynamic improvement, although executive function, which is specific to prefrontal function, might not be reversible.

Incidence of and risk factors for chronic subdural hematoma after endoscopic endonasal surgery: quantitative analysis of pneumocephalus.

OBJECTIVE: Chronic subdural hematoma (CSDH) is known to occur after endoscopic endonasal surgery (EES); however, the detailed clinical picture remains unclear. In this study, the authors aimed to examine the incidence of and risk factors for post-EES CSDH, with a focus on the quantitative evaluation of postoperative pneumocephalus. METHODS: The authors retrospectively collected data on consecutive patients who, between November 2016 and December 2022, had undergone EES during which intraoperative cerebrospinal fluid (CSF) leakage occurred. Using CT images obtained immediately after surgery (CT0), the authors measured the extent of pneumocephalus in detail. The locations of pneumocephalus were divided into two groups: remote and local. Remote pneumocephalus was further subdivided into convexity and ventricular. The incidence of post-EES CSDH was calculated, and its risk factors were analyzed. RESULTS: Among the 159 EES patients included in the study, Esposito grade 1, 2, and 3 intraoperative CSF leakage was confirmed in 22 (14%), 27 (17%), and 110 (69%) patients, respectively. CSDH occurred in 6 patients (3.8%). One patient (0.6%) required unilateral burr hole surgery, whereas the hematomas spontaneously disappeared in the others. All CSDHs occurred in patients with Esposito grade 3 CSF leakage and convexity pneumocephalus on CT0. In the multivariate analysis of 149 sides with convexity pneumocephalus on CT0, the product of the diameter and the thickness of convexity pneumocephalus on CT0 was significantly associated with subsequent CSDH (OR 1.21, 95% CI 1.06-1.38, p = 0.004). Using a cutoff value of 10 cm2, CSDH development could be predicted with a sensitivity of 0.82 and specificity of 0.74. CONCLUSIONS: The incidence of post-EES CSDH is acceptably low, and surgery is rarely required. Patients with extensive convexity pneumocephalus on immediate postoperative CT are prone to develop CSDH and thus should be carefully monitored.

Sustaining consistent cobalt-60 dose rate enhances radiosurgical outcomes in brain arteriovenous malformation management.

BACKGROUND AND PURPOSE: The impact of cobalt-60 dose rate (Co-60 DR) on outcomes of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) remains fully elucidated. This study explored the association between Co-60 DR and SRS outcomes in AVM treatment. MATERIALS AND METHODS: 772 AVM patients from 1990 to 2020 were included. High DR was defined as ≥ 2.4 Gy/min. AVM patients were categorized into 3 cohorts based on the nidus volume: small (<5 mL), medium (≥5 mL and < 10 mL), and large (≥10 mL). The primary endpoint was AVM obliteration; secondary endpoints included post-SRS hemorrhage. RESULTS: Cumulative obliteration rates of the large AVM were significantly increased in the high DR group than those in the low DR group (84 % vs. 45 % at 5 years, log-rank test; p = 0.011). Multivariable analysis showed that the obliteration rate was significantly elevated for the high DR group in the large AVM cohort with an adjusted hazard ratio (HR) of 1.78 (95 % confidence interval [CI]: 1.00-3.17, p = 0.049). Post-SRS hemorrhage rates of the entire cohort were significantly decreased in the high DR group than in the low DR group (2.5 % vs. 5.3 % at 5 years, log-rank test; p = 0.035). Multivariable analysis revealed post-SRS hemorrhage was reduced in the high DR group with an adjusted HR of 0.47 (95 % CI: 0.24-0.92, p = 0.026). CONCLUSION: High DR may lead to increased efficiency for large AVMs and decreased post-SRS hemorrhage in all AVM cases. Sustaining a higher Co-60 DR could potentially yield favorable outcomes for SRS for AVMs.

Role of stereotactic radiosurgery for recurrent skull base acinic cell carcinoma: illustrative case.

BACKGROUND: Acinic cell carcinomas (AcCCs), rare malignancies of the salivary glands, often recur and metastasize, particularly in the skull base. Conventional radical resection can be invasive for skull base AcCCs adjacent to cranial nerves and major vasculature, and the effectiveness of stereotactic radiosurgery (SRS) as an alternative is not well established. OBSERVATIONS: This case report details the application of SRS for recurrent skull base AcCCs. A 71-year-old male with a history of resection for a right mandibular AcCC 23 years earlier experienced tumor recurrence involving the right cavernous sinus and nasal cavity. He underwent endoscopic transnasal surgery followed by SRS targeting different tumor locations-the cavernous sinus to the pterygopalatine fossa, maxillary sinus, and clivus-each with a prescribed dose of 20 Gy to the 40% to 50% isodose line. After the first skull base metastasis, additional sessions of localized SRS after endoscopic surgery led to a 12-year survival without sequela. LESSONS: This is a report indicating that SRS for skull base AcCCs can achieve favorable local control, functional preservation, and long-term survival. SRS may be suitable for skull base AcCC given the lesion's tendency toward multiple local recurrences. Further investigation is needed to validate the treatment's efficacy.