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Vestibular Schwannoma (VS), previously known as acoustic neuroma, constitutes the majority of tumours found in the cerebellopontine angle (CPA). Most guidelines for managing CPA tumours have been developed by high-income countries (HICs). However, these guidelines often fall short in addressing the unique challenges encountered in low- and middle-income countries (LMICs), such as Pakistan. In LMICs, issues related to a limited healthcare workforce, inadequate infrastructure, and constrained financial resources hinder the effective implementation of these HIC-derived guidelines. Additionally, it has been observed that VS tends to present at a larger size in LMICs compared to HICs. Given that VS is the predominant type of CPA tumour and other types are covered under separate guidelines, this article aims to provide practical, contextspecific recommendations for the screening, diagnosis, and management of Vestibular Schwannoma in LMIC settings. Our focus is to bridge the gap in care strategies and adapt them to the resource constraints and clinical realities of LMICs.

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Surgical removal remains the primary treatment for most brain tumours. However, radiosurgery presents an effective, less invasive alternative or additional treatment for certain types. Our goal was to explore radiosurgery's roles in treating various brain tumours, focussing on its application in low- and middle-income countries (LMICs). We reviewed all relevant systematic reviews, metaanalyses, and guidelines to determine the most effective radiosurgical approaches. Additionally, we consulted a panel of experts with over ten years of experience in LMICs, such as Pakistan. For brain tumours, stereotactic radiosurgery should generally follow a confirmed histopathological diagnosis. Exceptions include tumours identified through Magnetic Resonance Imaging (MRI), like Vestibular Schwannoma (VS), pre-diagnosed Neurofibromatosis type 2 (NF2), multiple typical meningiomas, and metastases with a known histology from another site. While radiosurgery is gaining traction as a primary and adjunct treatment in some LMICs, the lack of regional guidelines, trained personnel, and collaboration among specialists hinders its wider adoption. Addressing these gaps is crucial for expanding radiosurgical care in these regions.

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Background: Facial nerve paralysis is a severe dysfunction after vestibular schwannoma (VS) surgery. Methods: This monocentric study analyzed 61 patients who underwent sporadic VS surgery in a standardized manner. The primary endpoint was the facial nerve outcome (FNO) at 3 months after VS surgery. FNO was dichotomized into "good" (House-Brackmann (HB) score ≤ 2) and "poor" (HB > 2). Results: Poor FNO was observed in 11 patients (18.0%) at 3 months after VS surgery. Radiomic tumor shape features were analyzed, and the AUC of elongation in the prediction of a poor HB at 3 months was 0.70 (95% CI: 0.56-0.85, p = 0.03) and the optimum threshold value (≤/>0.35) yielded a sensitivity and specificity of 64.0% and 75.4%, respectively. Multivariable logistic regression analyses considering the extent of resection (0.35) revealed that more elongated VSs (≤0.35; OR: 5.8; 95%CI: 1.2-28.2; p = 0.03) and those with an increased EoR (≥93.4%; OR: 6.5; 95%CI: 1.0-42.5; p = 0.05) are independently associated with poorer FNO at 3 months after surgery. Conclusions: Highly elongated VS shape seems to be a risk factor for worsened facial nerve outcome at 3 months after surgery for Koos grade 3 and 4 tumors.

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BACKGROUND: Definition of tumor control and treatment failure after Gammaknife radiosurgery (GKRS) for vestibular schwannoma (VS) is still debated. The lack of knowledge on the dynamics of tumor evolution can lead to misinterpretation and subsequent inappropriate second treatment. The aim of this study was to evaluate the post-GKRS dynamics of evolution of tumor volume, and characterize volumetric patterns. METHODS: We included patients with sporadic VS treated by GKRS with an MRI follow-up of minimum 3 years. A clustering in 2 steps was performed: definition of the patterns of evolution based on a subset of patients with the most comprehensive follow-up, then assignment of the remaining patients on a best fit basis. The minimum length of follow-up was assessed by measuring the consistency of the clusters over time (Adjusted Rand Index and Normalized Mutual Information). An analysis of the discriminant variables was finally performed. RESULTS: 1,607 patients were included (median follow-up: 67 months). Five patterns were defined with one pattern gathering almost all cases of treatment failure. The clustering at 5 years afforded the highest consistency with long-term follow-up. Discriminant variables for clusters were: sex, initial symptoms, delay of diagnosis, Koos grading, fundus invasion, and number of isocenters. CONCLUSIONS: The definition of these robust distinct patterns is likely to help tremendously the physicians to distinguish tumor control from potential failure. We advocate for no retreatment decision before 5 years post-GKRS. Further investigations are required to decide if the dynamics of evolution can be predicted at GKRS on an individual basis.

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Sporadic vestibular schwannomas (VSs) often exhibit slow or negligible growth. Nevertheless, some VSs increase significantly in volume within a few months or grow continuously. Recent evidence indicates a role of inflammation in promoting VS growth. Therefore, our study aimed to identify cytokines, which are associated with larger VSs. The expression of different cytokines in VS tumor samples and VS primary cultures was investigated. Additionally, the concentration of cytokines in cell culture supernatants of VS primary cultures and cerebrospinal fluid (CSF) of VS patients and healthy controls were determined. Correlation analysis of cytokine levels with tumor volume, growth rate, Koos grade, age, and hearing was examined with Spearman's-rank test. The mRNA expression of CC-chemokine ligand (CCL) 18, growth differentiation factor (GDF) 15, and interferon regulatory factor 4 correlated positively with tumor volume. Moreover, the amount of GDF15 in the cell culture supernatant of primary cells correlated positively with tumor volume. The concentrations of the cytokines CCL2, CCL5, and CCL18 and transforming growth factor beta (TGFB) 1 in the CSF of the patients were significantly different from those in the CSF controls. Inhibition of immune cell infiltration could be a putative approach to prevent and control VS growth.

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AIMS/OBJECTIVES: Unlike air-conducted sounds (ACS) and bone-conducted vibration (BCV), galvanic vestibular stimulation (GVS) evokes vestibular evoked myogenic potentials (VEMPs) from the vestibular nerve. MATERIALS AND METHODS: Case-control study was conducted in unilateral VS patients pre-operatively. Healthy ears were controls. Patients examined ACS, BCV and GVS ocular VEMP (oVEMP) and cervical VEMP (cVEMP), caloric test, video head impulse test (vHIT), suppression head impulse paradigm (SHIMP) and pure tone audiometry (PTA). RESULTS: Seven (26.9%) tumors affected left ear and 19 (73.1%) on the right(p < .05). Response rates in VS group were statistically lower than control except for ACS-cVEMP (p < .05). Response rates of VEMPs in VS patients decreased with the tumor size grows. But not all BCV and GVS VEMPs disappeared in the largest tumor group. Abnormal rates of caloric test, vHIT gains and SHIMP were found. CONCLUSIONS AND SIGNIFICANCE: Response rates of GVS VEMPs decreased with the residual functional nerve fibers. GVS VEMPs help to differentiating labyrinthine and retro-labyrinthine lesions. GVS combined with BCV VEMPs probably reflex the tumor origin from the eighth cranial nerve and/or the remaining vestibular function.

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The management of vestibular schwannoma (VS) remains one of the most formidable challenges in neurosurgery owing to the eloquent nature of surrounding anatomy. Although endoscopy-assisted microsurgery has recently gained momentum in cerebellopontine angle region surgery, the feasibility of pure endoscopic technique has been rarely reported. Here we present the operative technique and preliminary outcomes of fully endoscopic retrosigmoid trans-petrosal fissure approach (ER-TPFA) for VS surgery. Clinical data of 36 consecutive cases of VS treated with the ER-TPFA from March 2021 to March 2023 were analyzed. The patients were placed in a modified lateral park-bench position, with the Dandy incision and suboccipital craniotomy performed. With the endoscopic holder, endoscopic procedures were performed using standard two-hand microsurgical techniques by one surgeon. Arachnoidal dissection of the petrosal fissure was performed for identifying the brainstem end of facial nerve and separating the tumor from the cerebellum, without brain retraction seen in traditional microsurgical technique. The tumors had an averaged size of 3.0 cm in diameter. According to the Hannover classification, nearly all the tumors were grade III-IV (97.3%). Using ER-TPFA, 33 patients (91.7%) achieved gross total resection. Anatomic preservation of the facial nerve was achieved in 35 cases, with 33 patients (91.7%) retaining a House-Brackmann score of 1-2 postoperatively. Four out of ten patients still had serviceable hearing 6 months after operation. Postoperatively, there was no post-craniotomy hematoma, cerebellar edema, and new-onset cerebellar ataxia. With a better visualization of the cerebellopontine angle region, ER-TPFA may help preserve facial nerve function and maintain high gross total resection rate while minimizing complications. We believe this retractorless technique can be a safe and effective alternative for the management of VS with satisfactory clinical results.

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BACKGROUND: The management of vestibular schwannomas (VS) encompasses a choice between conservative "wait-and-scan" (WAS) approach, stereotactic radiosurgery (SRS) or open microsurgical resection. Currently, there is no consensus on the optimal management approach for small to medium sized VS. This study aims to compared outcomes related to hearing in patients with small and medium sized VS who underwent initial treatment with WAS versus SRS. METHODS: A systematic review of the available literature was conducted using PubMed/MEDLINE, Embase, and Cochrane up December 08, 2023. Meta-analysis was performed using a random-effect model to calculate mean difference (MD) and relative risk (RR). A leave-one-out analysis was conducted. The risk of bias was assessed via the Risk of Bias in Non-randomized Studies-Interventions (ROBINS-I) and Cochrane Risk of Bias assessment tool (RoB-2). Ultimately, the certainty of evidence was evaluated using the GRADE assessment. The primary outcomes were serviceable hearing, and pure-tone average (PTA). The secondary outcome was the Penn Acoustic Neuroma Quality of Life Scale (PANQOL) total score. RESULTS: Nine studies were eligible for inclusion, comprising a total of 1,275 patients. Among these, 674 (52.86%) underwent WAS, while 601 patients (47.14%) received SRS. Follow-up duration ranged from two to eight years. The meta-analysis indicated that WAS had a better outcome for serviceable hearing (0.47; 95% CI: 0.32 - 0.68; p < 0.001), as well as for postoperative functional measures including PTA score (MD 13.48; 95% CI 3.83 - 23.13; p < 0.01), and PANQOL total score (MD 3.83; 95% CI 0.42 - 7.25; p = 0.03). The overall certainty of evidence ranged from "very low" to "moderate". CONCLUSIONS: Treating small to medium sized VS with WAS increases the likelihood of preserving serviceable hearing and optimized PANQOL overall postoperative score compared to SRS. Nevertheless, the limited availability of literature and the methodological weakness observed in existing studies outline the need for higher-quality studies.

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Objective The aim of this study was to assess the ability to smile following a hypoglossal-facial nerve transfer (N12-N7). Design This is a retrospective chart review. Setting National tertiary referral center for skull base pathology. Participants Seventeen patients. Main Outcome Measures The ability to smile following an N12-N7 transfer was assessed by five medical doctors on photographs of the whole face and frontal, orbital, and oral segments. The (segmented) photographs were scored for the symmetry, asymmetry, and correct or incorrect assessment of the affected side. Results Seventeen patients were analyzed by 5 assessors providing 85 assessments. The whole face at rest was judged symmetrical in 26% of the cases and mildly asymmetrical in 56%. Frontal, orbital, and oral segments were symmetrical in 63, 20, and 35%, respectively. The affected side was correctly identified in 76%. When smiling, the whole face was symmetrical in 6% and mildly asymmetric in 59%. The affected side was correctly identified in 94%. The frontal, orbital, and oral segments during smiling were symmetrical in 67, 15, and 6%, respectively. The affected side of the frontal, orbital, and buccal facial segments during smiling was correctly identified in 89, 89, and 96%, respectively. Interobserver variability with Fleiss' kappa analysis showed that the strength of the agreement during smile of the total face was good (0.771) Conclusion Following an N12-N7 transfer, a good facial symmetry at rest can be achieved. During smiling, almost all patients showed asymmetry of the face, which was predominantly determined by the orbital and oral segments. To improve the ability to smile after an N12-N7 transfer, additional procedures are needed.

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Background: Treatment outcome data of stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) in patients ≥75 years (late elderly) are lacking. Approximately 39% of patients ≥75 years with VS were reported to experience severe facial palsy after surgical removal. This study compared the treatment outcomes post-SRS for VS between patients ≥75 and 65-74 years (early elderly). Methods: Of 453 patients who underwent gamma knife SRS for VS, 156 were ≥65 years old. The late and early elderly groups comprised 35 and 121 patients, respectively. The median tumor volume was 4.4 cc, and the median radiation dose was 12.0 Gy. Results: The median follow-up periods were 37 and 56 months in the late and early elderly groups, respectively. Tumor volume control was observed in 27 (88%) and 95 (83%) patients (P = 0.78), while additional procedures were required in 2 (6%) and 6 (6%) patients (P = 1.00) in the late and early elderly groups, respectively. At the 60th and 120th months post-SRS, the cumulative tumor control rates were 87%, 75%, 85%, and 73% (P = 0.81), while the cumulative clinical control rates were 93% and 87%, 95%, and 89% (P = 0.80), in the late and early elderly groups, respectively. In the early elderly group, two patients experienced facial pain, and one experienced facial palsy post-SRS; there were no adverse effects in the late elderly group (both P = 1.00). Conclusion: SRS is effective for VS and beneficial in patients ≥75 years old as it preserves the facial nerve.

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BACKGROUND: Elderly patients with vestibular schwannoma (VS) are commonly observed. OBJECT: Retrospective analysis of 25 patients aging ≥ 70 operated on in our neurosurgical department for unilateral VS. The purpose of our study is to propose an algorithm for the treatment of VS in elderly patients. METHODS: American Society of Anesthesiology (ASA) Grade I-II patients and Grade III with life-threatening tumors were enrolled. Karnofsky Performance Status Scale (KPS) was used for evalutation of the quality of life. The House-Brackmann (HB) scale for facial nerve (FN) outcome was used. Tumor size was categorized according to Koos' classification. A retrosigmoid approach was used in all cases, except one in which a translabyrinthine approach was performed. Surgical removal graduation: total (GTR), near total (NTR > 95%), subtotal (STR > 90%). The clinical and radiological follow-up period was set first at six months and then at one year after surgery. FN results evaluation was performed at one year, categorized according to House-Brackmann grades I-VI. RESULTS: Mean age: 74,4 years (70-83); 28% ASA I, 56% ASA II, 16% ASA III. Mean tumor size: 2,7 cm (1,5-4,2 cm). GTR/NTR: 68%, STR 32%. Mortality was zero. At last follow-up (one year after surgery) FN results were: HBI 81%, HBII 9.5%, HBIII 9.5%; HB IV 0%. Only 4 patients had preoperative HB IV, of whom one improved from HB IV to HB III. Transient complications occurred only in large VS. Re-growth of residue after STR was observed in 3 cases, treated with SRS in 2 cases and observed in 1. CONCLUSIONS: An algorithm of treatment of vestibular schwannoma in the elderly is proposed. In particular, in patients in general good conditions, age does not appear to be a major contraindication for microsurgery of VS. FN results at last follow-up are satisfactory and the complication rates are acceptable.

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OBJECTIVE: To preserve facial nerve function in vestibular schwannoma (VS) microsurgery, some have advocated subtotal resection (STR) if the tumor is densely adherent to a thinned facial nerve. The objective of this study was to determine if residual volume is associated with progression and whether there is a threshold residual volume that should be pursued during STR to prevent recurrence. A secondary objective of this study was to determine whether facial nerve function at last follow-up was associated with extent of resection (EOR). METHODS: Clinical and radiographic data were retrospectively collected from the records of 164 patients with VS who underwent resection. Tumor volumes were measured using Visage, and standard statistical methods were used. The House-Brackmann scale was used to assess changes in facial nerve function before surgery and at last follow-up. RESULTS: Sixty-one patients (37%) received gross-total resection (GTR) and 103 (63%) received STR. The median clinical and radiographic follow-ups were 49 and 48 months, respectively. The median residual volume was 0.5 cm3 after STR. Kaplan-Meier actuarial survival analysis revealed a 96.3% 5-year progression-free survival (PFS) rate after GTR, which was greater than that after STR (84.5%, p = 0.03). Recursive partitioning analysis of patients receiving STR revealed a residual volume of 0.60 cm3 as the optimal threshold for recurrence. Patients with residual volume ≥ 0.60 cm3 had a 76.0% 5-year PFS, regardless of adjuvant SRS, which was lower than that for patients undergoing GTR (96.3%) or STR (95.6%) with residual volumes < 0.60 cm3 (p < 0.01). On Cox regression analysis, residual volume ≥ 0.60 cm3 (HR 14.4, p = 0.01) was independently associated with progression, even when accounting for patient age, adjuvant radiosurgery, and preoperative tumor size. In 112 patients with at least 24 months of follow-up after their last treatment, tumor control was achieved in 111 (99.1%) patients at a median last follow-up of 71 months. Worse facial nerve function at the last follow-up was independently associated with prior treatment for VS (adjusted OR 3.7, p = 0.04), but not residual volume cohort or preoperative tumor volume. CONCLUSIONS: Residual volume > 0.60 cm3 after VS resection was independently associated with tumor progression, even accounting for adjuvant SRS. These data support maximizing the EOR during VS surgery, even if GTR cannot be safely achieved.

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INTRODUCTION: Lateral skull base (LSB) and middle ear pathologies often involve the facial nerve (FN), and their treatment may require FN sacrifice. Cases with unidentifiable proximal stump or intact FN with complete FN palsy, necessitate FN anastomosis with another motor nerve in order to restore innervation to the mimicking musculature. The results of hypoglossal-to-facial nerve anastomosis (HFA) and masseteric-facial nerve anastomosis in patients with facial paralysis after middle ear and LSB surgeries, are presented and compared. METHODS: Adult patients with total definitive facial paralysis after middle ear or LSB surgery undergoing facial nerve reanimation through hypoglossal or masseteric transfer anastomosis were enrolled. The facial nerve function was graded according to the House Brackmann grading system (HB). The facial function results at 3 months, 6 months, 12 months, 18 months and at the last follow up (more than 18 months) are compared. RESULTS: 153 cases of LSB and middle ear surgery presented postoperative facial palsy and underwent facial nerve reanimation surgery with HF in 85 patients (55.5%) and MF in 68 patients (44.5%). The duration of the FN palsy before reconstructive surgery was inversely associated to better FN results, in particular with having a grade III HB (p = 0.003). Both techniques had significantly lower HB scores when an interval between palsy onset and reanimation surgery was 6 months or less (MF p = 0.0401; HF p = 0.0022). Patients who underwent a MF presented significant improvement of the FN function at 3 months from surgery (p = 0.0078). At the last follow-up, 63.6% recovered to a grade III HB and 22.7% to a grade IV. On the other hand, the first significant results obtained in the HF group were at 6 months from surgery (p < 0.0001). 67.8% of patients had a grade III HB after a HF at the last follow-up, 28.8% a grade IV. FN grading at 6 months from surgery was significantly lower in the MF group compared to the HF (p = 0.0351). The two techniques had statistically similar results at later follow-up evaluations. DISCUSSION/CONCLUTION: MF was associated to initial superior results, presenting significant facial recovery at 3 months, and significantly better functional outcomes at 6 months from surgery compared to HF. Although later results were not significantly different in this study, earlier results have an important role in order to limit the duration of risk of corneal exposure.

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This study aimed to reveal the preferred initial treatment for Koos grade 3 vestibular schwannomas (VS). We performed a two-institutional retrospective study on 21 patients with Koos grade 3 VS undergoing resection at Yokohama Medical Center and 37 patients undergoing radiosurgery at Yokohama Rosai Hospital from 2010 to 2021. Tumor control, complications, and functional preservation were compared. The median pre-treatment volume and follow-up duration were 2845 mm3 and 57.0 months, respectively, in the resection group and 2127 mm3 and 81.7 months, respectively, in the radiosurgery group. In the resection group, 16 (76.2%) underwent gross total resection, and three patients (14.3%) experienced regrowth; however, no one required additional treatment. In the radiosurgery group, the tumor control rate was 86.5%, and three cases (8.1%) required surgical resection because of symptomatic brainstem compression. Kaplan-Meier analyses revealed that tumors with delayed continuous enlargement and large thin-walled cysts were significantly associated with poor prognostic factors (p = 0.0027, p < 0.001). The pre-radiosurgery growth rate was also associated with the volume increase (p = 0.013). Two cases (9.5%) required additional operation due to complications such as post-operative hematoma and cerebrospinal fluid leaks in the resection group, whereas temporary cranial neuropathies were observed in the radiosurgery group. Two patients (9.5%) had poor facial nerve function (House-Brackmann grading grade 3) in the resection group, while no one developed facial paresis in the radiosurgery group. Trigeminal neuropathy improved only in the resection group.Radiosurgery can be considered for the treatment of Koos grade 3 VS for functional preservation. However, resection may also be considered for patients with severe trigeminal neuropathy or a high risk of volume increments, such as large thin-walled cysts and rapid pre-treatment growth.

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PURPOSE: The tumor microenvironment (TME) plays a crucial role in tumor progression and treatment response. Radiomics offers a non-invasive approach to studying the TME by extracting quantitative features from medical images. In this study, we present a novel approach to assess the stability and discriminative ability of radiomics features in the TME of vestibular schwannoma (VS). METHODS: Magnetic Resonance Imaging (MRI) data from 242 VS patients were analyzed, including contrast-enhanced T1-weighted (ceT1) and high-resolution T2-weighted (hrT2) sequences. Radiomics features were extracted from concentric peri-tumoral regions of varying sizes. The intraclass correlation coefficient (ICC) was used to assess feature stability and discriminative ability, establishing quantile thresholds for ICCmin and ICCmax. RESULTS: The identified thresholds for ICCmin and ICCmax were 0.45 and 0.72, respectively. Features were classified into four categories: stable and discriminative (S-D), stable and non-discriminative (S-ND), unstable and discriminative (US-D), and unstable and non-discriminative (US-ND). Different feature groups exhibited varying proportions of S-D features across ceT1 and hrT2 sequences. The similarity of S-D features between ceT1 and hrT2 sequences was evaluated using Jaccard's index, with a value of 0.78 for all feature groups which is ranging from 0.68 (intensity features) to 1.00 (Neighbouring Gray Tone Difference Matrix (NGTDM) features). CONCLUSIONS: This study provides a framework for identifying stable and discriminative radiomics features in the TME, which could serve as potential biomarkers or predictors of patient outcomes, ultimately improving the management of VS patients.

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Background and objective: After vestibular schwannoma (VS) surgery, some patients exhibit different degrees of peripheral facial paralysis, which can seriously affect their quality of life. The recovery of facial nerve function after surgery typically takes a considerable amount of time; therefore, the recovery of facial nerve function depends mainly on the rehabilitation treatment and nursing after discharge. In the past, we implemented conventional paralysis rehabilitation nursing program for patients with facial paralysis due to VS surgery. However, several patients with facial paralysis have bad compliance and do not achieve ideal facial nerve function recovery. Therefore, this study aimed to investigate whether modified facial paralysis rehabilitation nursing improves the effectiveness of rehabilitation of facial paralysis after VS surgery by analysing the clinical data of patients. Methods: We screened the patients with facial paralysis after VS surgery from December 2019 to May 2023. The patients were divided into the conventional and modified groups based on the different nursing programs (conventional vs. modified facial paralysis rehabilitation nursing program) to compare the differences in facial nerve function, quality of life of patients, and compliance of rehabilitation between the two groups. Results: We analysed 128 patients with facial paralysis after VS surgery who met the inclusion and exclusion criteria; 65 and 63 patients in the conventional and modified group, respectively. The number of patients in the modified group with House-Brackmann grade changes >0 in facial nerve function was significantly higher than that in the conventional group 3 months after surgery (82.5 % vs 63.1 %, p = 0.01). Except for the lacrimal control score, the mean scores of the Chinese version of the FaCE scale were significantly higher in the modified group than those in the conventional group at 1 and 3 months postoperatively. Conclusions: The modified facial paralysis rehabilitation nursing, i.e., integrated use of facial expressive muscle exercises and facial massage with video-assisted education, substantially improved the facial nerve function, quality of life, and compliance of rehabilitation nursing of patients with facial paralysis after VS surgery.

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Vestibular Schwannoma (VS) is a rare tumor with varied incidence rates, predominantly affecting the 60-69 age group. In the era of artificial intelligence (AI), deep learning (DL) algorithms show promise in automating diagnosis. However, a knowledge gap exists in the automated segmentation of VS using DL. To address this gap, this meta-analysis aims to provide insights into the current state of DL algorithms applied to MR images of VS. METHODOLOGY: Following 2020 PRISMA guidelines, a search across four databases was conducted. Inclusion criteria focused on articles using DL for VS MR image segmentation. The primary metric was the Dice score, supplemented by relative volume error (RVE) and average symmetric surface distance (ASSD). RESULTS: The search process identified 752 articles, leading to 11 studies for meta-analysis. A QUADAS- 2 analysis revealed varying biases. The overall Dice score for 56 models was 0.89 (CI: 0.88-0.90), with high heterogeneity (I2 = 95.9%). Subgroup analyses based on DL architecture, MRI inputs, and testing set sizes revealed performance variations. 2.5D DL networks demonstrated comparable efficacy to 3D networks. Imaging input analyses highlighted the superiority of contrast-enhanced T1-weighted imaging and mixed MRI inputs. DISCUSSION: This study fills a gap in systematic review in the automated segmentation of VS using DL techniques. Despite promising results, limitations include publication bias and high heterogeneity. Future research should focus on standardized designs, larger testing sets, and addressing biases for more reliable results. DL have promising efficacy in VS diagnosis, however further validation and standardization is needed. CONCLUSION: In conclusion, this meta-analysis provides comprehensive review into the current landscape of automated VS segmentation using DL. The high Dice score indicates promising agreement in segmentation, yet challenges like bias and heterogeneity must be addressed in the future research.

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INTRODUCTION: Facial nerve palsies may develop during the postoperative period of microsurgical removal of vestibular schwannomas (VSs), even after normal facial function for days or weeks after surgery. The aim of this study was to identify the pathomechanism and predictive factors of delayed palsy. MATERIAL AND METHOD: The clinical data of 193 patients who underwent vestibular schwannoma surgery between 2012 and 2021 were retrospectively analyzed. A total of 134 patients were included. The patients showed intact facial nerve function up to 24 h after surgery. All patients (n = 20) with palsy from postoperative day 4 were included and collectively referred to as delayed facial nerve palsy (DFNP). Various factors were checked using a binomial regression analysis. RESULTS: The mean age of patients with DFNP was 57.8 years (55% female, 45% male). 70% had VS with KOOS ≥ 3, and 60% underwent surgery via a translabyrinthine approach Among the 16 patients with DFNP-related neurotropic pathogens, 25% were seropositive for herpes simplex virus. Most patients (n = 9/20) experienced onset of palsy between postoperative days 6 and 10. Of the four variables included in the significance test, three were significant: KOOS ≥ 3 (p < .04), ipsilateral vestibular organ failure (p < .05), and age group (p < .03). After therapy, 100% of patients recovered almost complete facial nerve function. The parameters mentioned above (KOOS classification and ipsilateral vestibular dysfunction) could be proven risk factors for the occurrence of DFNP.

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OBJECTIVE: Resection of the vestibular schwannoma causes acute peripheral vestibular loss. The process of central compensation starts immediately afterward. The rehabilitation goal is to support this process and restore the quality of life. MATERIALS AND METHODS: In this prospective single-center study, 67 consecutive patients underwent vestibular schwannoma resection (40 females, mean age 52 ± 12 years). The patients were divided into three groups: the prehabilitation with intratympanic gentamicin group, the virtual reality group (optokinetic stimulation via virtual reality goggles in the first ten days after the surgery), and the control group. All patients were examined with objective methods and completed questionnaires before the prehabilitation, before the surgery, at the hospital discharge, and after three months. RESULTS: Intratympanic gentamicin prehabilitation leads ipsilaterally to a significant aVOR reduction in all semicircular canals (p < 0.050), the increase of the unilateral weakness in air calorics (p = 0.026), and loss of cVEMPs responses (p = 0.017). Prehabilitation and postoperative exposure to virtual reality scenes improved the patient's perception of vertigo problems according to Dizziness Handicap Inventory (p = 0.039 and p = 0.076, respectively). These findings conform with the optokinetic testing results, which showed higher slow phase velocities at higher speeds (40 deg/s) in both targeted groups compared to the control group. CONCLUSION: Preoperative intratympanic gentamicin positively affects peripheral vestibular function, influencing balance perception after VS resection. In long-term follow-up, prehabilitation and postoperative exposure to virtual reality improve patients' quality of life in the field of vertigo problems.

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OBJECTIVE: To optimize surgical positioning for posterior fossa surgery (PFS) using the semisitting position (SSP) to avoid venous air embolism (VAE) and its possible life-threatening consequences, the authors evaluated their experiences with the SSP by analyzing a large cohort of PFS patients. METHODS: A retrospective analysis of the charts of 202 consecutive PFS patients (median age 54 years, IQR 41-61 years; 121 females) with various tumor or vascular conditions who underwent surgery in an SSP between 2019 and 2022 was performed. Age, sex, weight, height, BMI, American Society of Anesthesiologists (ASA) class, histology, duration of surgery, and length of hospital stay were assessed. Transesophageal echocardiography was used pre- and intraoperatively to monitor for and assess the degree of VAE. RESULTS: Altogether, VAE occurred in 30 of 202 (14.9%) patients, with clinically relevant VAE occurring in 14 of 202 (7%) patients. The grades of VAE were I, III, and IV in 16 (8%), 4 (2%), and 10 (5%) patients, respectively. Patient height (p = 0.04), ASA class (p = 0.03), and ASA class ≤ II (p = 0.02) remained the only preoperative statistically significant risk factors for intraoperative VAE, with a median height of 178 cm (IQR 172-184 cm) in patients with clinically relevant VAE compared with 170 cm (IQR 164-176 cm) in those without VAE. CONCLUSIONS: In summary, the data demonstrate that SSP can be used safely for PFS when taking special care to optimize positioning in tall and lower-grade ASA patients intraoperatively.