Background:Meningiomas affect up to 80% of patients with NF2-related schwannomatosis during their lifetime. They are managed by active monitoring, surgery, and stereotactic radiosurgery (SRS). This paper aims to synthesize the existing data, evaluate outcomes, and inform future trial design. Methods:Systematic review and meta-analysis conducted using the PRISMA framework. Six databases were searched from inception to September 2025. Patient demographics, intervention data, and outcomes were collected and pooled analyses performed. Studies were appraised using the NIH quality assessment tool. Results:Fifteen studies with 937 patients and 3637 meningiomas were included. The pooled proportion of female patients was 59.6% (95% confidence interval [CI]: 55.4-63.7). A total of 2082 tumors were monitored (mean follow-up 5.55-9.18 years) with a weighted mean growth rate of 0.508 cm3/year (95% CI: 0.0244-0.992) (available in 748 meningiomas). The weighted pooled proportion of monitored patients who developed de novo meningiomas across 3 studies was 24.6% (95% CI: 2.73-58.7). Surgical resection was performed in 203 meningiomas, with an under-reported postintervention follow-up and a pooled risk of tumor recurrence of 12.5% (95% CI: 7.98-17.9). Stereotactic radiosurgery was used in 665 meningiomas. The pooled risk of treated tumor progression was 6.29% (95% CI: 4.57-8.25), median follow-up 3.58 to 9.25 years. The pooled local control rates at 3 and 5 years were 97.1% (95% CI: 94.7-98.8) and 91.2% (95% CI: 88.4-93.6), respectively. Conclusion:NF2-associated meningiomas are challenging to manage due to their multiplicity, high growth rate, and World Health Organization grade. Active monitoring, surgery, and SRS are viable treatment options. Here, we evaluate existing outcome data to guide future trial design.

Introduction Skull base meningiomas (SBMs) are often subtotally resected and there is a paucity of evidence regarding the long-term rates of postoperative tumor progression. We aimed to investigate the factors that influence tumor recurrence in patients with an extended period of follow-up. Methods Surgically resected tumors with long-term radiological follow-up were included for analysis. Data were collected on patient demographics, anatomical location, Simpson grade, World Health Organization (WHO) grade, modality of reintervention, and functional status. Recurrence was defined as tumor progression requiring intervention. Kaplan-Meier method and log-rank test were used to calculate recurrence-free probability. Cox regression analysis was used to determine factors associated with tumor progression. Results Sixty-one patients were identified. Median radiological follow-up was 11.25 (IQR 4.3) years. Median age at first surgery was 50 (IQR 17) years. A total of 55/61(90%) tumors were WHO grade I and 6/61(10%) were grade II. Gross total resection (GTR) was achieved in 37/61 (60.7%) patients with subtotal resection (STR) in 24/61 (39.3%). In total, 28/61(45.9%) demonstrated recurrence/regrowth with a median time to recurrence of 2.8 (IQR 5) years. Also, 15/37 (40.5%) and 13/24 (54.2%) patients with GTR and STR, respectively, had tumor recurrence. Of the 28 recurrences, 4/28 (14.3%) underwent reresection, 9/28 (32.1%) were managed with radiotherapy, and 15/28 (53.6%) received both reresection and radiotherapy. Tumor grade was the only significant predictor of tumor recurrence (p = 0.033). Neurological function at last follow-up was significantly worse (modified Rankin scale >2) in patients with recurrence (p = 0.035). Conclusion Surgically resected SBMs are associated with a significant recurrence rate during prolonged follow-up, irrespective of the extent of resection achieved. We recommend a prolonged period of radiological surveillance for SBM following surgical resection.

OBJECTIVE:The aim of this study was to describe the natural history of incidental benign-appearing notochordal lesions of the skull base with specific attention to features that can make differentiation from low-grade chordoma more difficult, namely contrast uptake and bone erosion. METHODS:In this retrospective case series, the authors describe the clinical outcomes of 58 patients with incidental benign-appearing notochordal lesions of the clivus, including those with minor radiological features of bone erosion or contrast uptake. RESULTS:All lesions remained stable during a median follow-up of almost 3 years. Thirty-seven (64%) patients underwent contrast-enhanced MRI; lesions in 14 (38%) of these patients exhibited minimal contrast enhancement. Twenty-seven (47%) patients underwent CT; lesions in 6 (22%) of these patients exhibited minimal bone erosion. CONCLUSIONS:These data make the case for monitoring selected cases of benign-appearing notochordal lesions of the clivus in the first instance even when there is minor contrast uptake or minimal bone erosion.

ObjectivesNew diagnostic criteria for NF2-related schwannomatosis (NF2) were published in 2022. An updated UK prevalence was generated in accordance with these, with an emphasis on the rate of de novo NF2 (a 50% frequency is widely quoted in genetic counselling). The distribution of variant types among de novo and familial NF2 cases was also assessed.MethodsThe UK National NF2 database identifies patients meeting updated NF2 criteria from a highly ascertained population cared for by England’s specialised service. Diagnostic prevalence was assessed on 1 February 2023. Molecular analysis of blood and, where possible, tumour specimens forNF2, LZTR1andSMARCB1was performed.Results1084 living NF2 patients were identified on prevalence day (equivalent to 1 in 61 332). The proportion with NF2 inherited from an affected parent was only 23% in England. If people without a confirmed molecular diagnosis or bilateral vestibular schwannoma are excluded, the frequency of de novo NF2 remains high (72%). Of the identified de novo cases, almost half were mosaic. The most common variant type was nonsense variants, accounting for 173/697 (24.8%) of people with an established variant, but only 18/235 (7.7%) with an inheritedNF2pathogenic variant (p<0.0001). Missense variants had the highest proportion of familial association (56%). The prevalence ofLZTR1-related schwannomatosis andSMARCB1-related schwannomatosis was 1 in 527 000 and 1 in 1.1M, respectively, 8.4–18.4 times lower than NF2.ConclusionsThis work confirms a much higher rate of de novo NF2 than previously reported and highlights the benefits of maintaining patient databases for accurate counselling.

ObjectivesTo determine the long‐term control rates and hearing outcomes for growing vestibular schwannoma in NF2‐related schwannomatosis (NF2) treated with stereotactic radiosurgery (SRS) and fractionated radiotherapy (FRT).MethodsRetrospective review of all patients treated with SRS/FRT between 1986 and2021 from a tertiary NF2 unit. Overall tumor control was defined as: (1) growth control (growth failure was defined as growth in any dimension of 3 millimetres or more from baseline post‐SRS/FRT), and (2) treatment control (no need for further intervention). Loss of serviceable hearing was defined as a drop in speech discrimination score below 50% after SRS/FRT.ResultsThere were 81 cases, with a mean duration of follow‐up of 125 months. Overall control rate was 72% (58/81), with 80% (65/81) growth control and 74% (60/81) treatment control. There was a 5‐year actuarial survival of 77% and 10‐year survival of 71%. Forty‐three percent (30/69) of cases did not have serviceable hearing at baseline. Of those remaining, 49% (19/39) preserved serviceable hearing during follow‐up at a mean of 106 months. Actuarial survival for preservation of serviceable hearing at 5 and 10 years was 69% and 53%. There were poorer outcomes with increasing genetic severity, and with baseline tumor size >3 cm. No cases of SRS/FRT‐related malignancy were identified at a mean follow‐up of 10 years.ConclusionStereotactic radiosurgery/fractionated radiotherapy are an effective option to treat growing vestibular schwannoma in patients with NF2 with the potential for hearing preservation in a proportion of patients.Level of Evidence4—Case Series Laryngoscope, 134:2364–2371, 2024

AbstractBackgroundRadiation treatment of benign tumors in tumor predisposition syndromes is controversial, but short-term studies from treatment centers suggest safety despite apparent radiation-associated malignancy being reported. We determined whether radiation treatment in NF2-related schwannomatosis patients is associated with increased rates of subsequent malignancy (M)/malignant progression (MP).MethodsAll UK patients with NF2 were eligible if they had a clinical/molecular diagnosis. Cases were NF2 patients treated with radiation for benign tumors. Controls were matched for treatment location with surgical/medical treatments based on age and year of treatment. Prospective data collection began in 1990 with addition of retrospective cases in 1969. Kaplan–Meier analysis was performed for malignancy incidence and survival. Outcomes were central nervous system (CNS) M/MP (2cm annualized diameter growth) and survival from index tumor treatment.ResultsIn total, 1345 NF2 patients, 266 (133-Male) underwent radiation treatments between 1969 and 2021 with median first radiotherapy age of 32.9 (IQR = 22.4–46.0). Nine subsequent CNS malignancies/MPs were identified in cases with only 4 in 1079 untreated (P < .001). Lifetime and 20-year CNS M/MP was ~6% in all irradiated patients—(4.9% for vestibular schwannomas [VS] radiotherapy) versus <1% in the non-irradiated population (P < .001/.01). Controls were well matched for age at NF2 diagnosis and treatment (Males = 133%–50%) and had no M/MP in the CNS post-index tumor treatment (P = .0016). Thirty-year survival from index tumor treatment was 45.62% (95% CI = 34.0–56.5) for cases and 66.4% (57.3–74.0) for controls (P = .02), but was nonsignificantly worse for VS radiotherapy.ConclusionNF2 patients should not be offered radiotherapy as first-line treatment of benign tumors and should be given a frank discussion of the potential 5% excess absolute risk of M/MP.

Diabetes insipidus (DI) is a recognised complication of pituitary surgery, with diagnosis requiring clinical observation aided by plasma and urine electrolytes and osmolalities. Copeptin is a stable surrogate marker of AVP release and has potential to facilitate prompt diagnosis of post-operative DI. This assay has been shown to accurately predict which patients are likely to develop DI following pituitary surgery. To determine whether copeptin analysis can be used to predict which patients are at risk of developing DI following trans-sphenoidal surgery (TSS). Seventy-eight patients undergoing TSS had samples taken for copeptin pre-operatively and at day 1 post-TSS. The majority of patients also had samples from day 2, day 8, and week 6 post-TSS. Results from patients who developed post-operative DI (based on clinical assessment, urine and plasma biochemistry and the need for treatment with DDAVP) were compared to those who did not. Patients with any evidence of pre-operative DI were excluded. Of 78 patients assessed, 11 were clinically determined to have developed DI. Differences were observed between patients with DI and those without in post-operative samples. Of note, there was a significant difference in plasma copeptin at day 1 post-operation (p = 0.010 on Kruskal–Wallis test), with copeptin levels greater than 3.4 pmol/l helping to rule out DI (91

Objective The COVID-19 pandemic has caused significant disruption to the surgical care of patients with pituitary tumors. Guidance issued early during the pandemic suggested avoiding transnasal approaches to minimize risks of transmitting COVID-19 to health care professionals involved in these procedures. Methods This observational, single-center study compares results of endoscopic transsphenoidal approach (TSA) for pituitary tumors since the start of the pandemic to a pre-pandemic period. Anesthetic time, surgical time, and complication rates were compared. Newly acquired COVID-19 infections and transmission rates to patients and staff were reviewed. Data were analyzed by using the independent t -test, Mann-Whitney U test, and Pearson Chi-square test, significance set at p <0.05. Results Over a 12-month period, a total of 50 and 69 patients underwent endoscopic TSA for pituitary tumor during and before the pandemic, respectively. All patients tested negative for COVID-19 preoperatively. Median duration of anesthesia was 35minutes (interquartile range [IQR]: 22) during the pandemic and 25minutes (IQR: 8, p =0.0002) pre-pandemic. Median duration of surgery was 70minutes (IQR: 28) during the pandemic and 79minutes (IQR: 33.75, p =0.126) pre-pandemic. There were no statistically significant differences between intraoperative CSF leaks and complication rates. No staff members tested positive for COVID-19. Three patients tested positive for COVID-19 postdischarge, but the infections were community acquired. Conclusion In contrast to published guidelines, adequate preoperative testing, a multidisciplinary approach and the implementation of standardized protocols and vaccination against COVID-19 allow for endoscopic transsphenoidal surgery to be performed safely in patients with pituitary pathology during the pandemic.

Abstract Background: Diabetes insipidus (DI) is a recognised complication of pituitary surgery, with diagnosis requiring clinical observation aided by plasma and urine electrolytes and osmolalities. Copeptin is a stable surrogate marker of AVP release and has potential to facilitate prompt diagnosis of post-operative DI. This assay has been shown to accurately predict which patients are likely to develop DI following pituitary surgery. Objective: To determine whether copeptin analysis can be used to predict which patients are at risk of developing DI following transsphenoidal adenomectomy (TSA).Methods: 78 patients undergoing TSA had samples taken for copeptin pre-operatively and at day 1 post-TSA. The majority of patients also had samples from day 2, day 8, and week 6 post-TSA. Results from patients who developed post-operative DI (based on clinical assessment, urine and plasma biochemistry and the need for treatment with DDAVP) were compared to those who did not. Patients with any evidence of pre-operative DI were excluded.Results: Of 78 patients assessed, eleven were clinically determined to have developed DI. Differences were observed between patients with DI and those without in post-operative samples. Of note, there was a significant difference in plasma copeptin at day 1 post-operation (p=0.010 on Kruskal-Wallis test), with copeptin levels greater than 3.4 pmol/L helping to rule out DI (91% sensitivity, 55% specificity at this cut off).Conclusion: In the post-TSA setting, copeptin is a useful rule-out test in patients with values above a defined threshold, which may facilitate earlier decision making and shorter hospital stays.

BACKGROUND: CRANIAL (CSF Rhinorrhoea After Endo nasal Intervention to the Skull Base) is a prospective multicenter observational study seeking to determine 1) the scope of skull base repair methods used and 2) corresponding rates of postoperative cerebrospinal fluid (CSF) rhinorrhea in the endonasal transsphenoidal approach (TSA) and the expanded endonasal approach (EEA) for skull base tumors. We sought to pilot the project, assessing the feasibility and acceptability by gathering preliminary data. METHODS: A prospective observational cohort study was piloted at 12 tertiary neurosurgical units in the United Kingdom. Feedback regarding project positives and challenges were qualitatively analyzed. RESULTS: A total of 187 cases were included: 159 TSA (85%) and 28 EEA (15%). The most common diseases included pituitary adenomas (n = 142/187), craniopharyngiomas (n = 13/187). and skull base meningiomas (n = 4/187). The most common skull base repair techniques used were tissue glues (n = 132/187, most commonly Tisseel), grafts (n = 94/187, most commonly fat autograft or Spongostan) and vascularized flaps (n = 51/187, most commonly nasoseptal). These repairs were most frequently supported by nasal packs (n = 125/187) and lumbar drains (n = 20/187). Biochemically confirmed CSF rhinorrhea occurred in 6/159 patients undergoing TSA (3.8%) and 2/28 patients undergoing EEA (7.1%). Four patients undergoing TSA (2.5%) and 2 patients undergoing EEA (7.1%) required operative management for CSF rhinorrhea (CSF diversion or direct repair). Qualitative feedback was largely positive (themes included user-friendly and efficient data collection and strong support from senior team members), demonstrating acceptability. CONCLUSIONS: Our pilot experience highlights the acceptability and feasibility of CRANIAL. There is a precedent for multicenter dissemination of this project, to establish a benchmark of contemporary practice in skull base neurosurgery, particularly with respect to patients u ndergoing EEA.

-BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, concerns have been raised regarding the increased risk of perioperative mortality for patients with COVID-19, and the transmission risk to healthcare workers, especially during endonasal neurosurgical operations. The Pituitary Society has produced recom-mendations to guide management during this era. We sought to assess contemporary neurosurgical practice and the effects of COVID-19. -METHODS: A multicenter prospective observational cohort study was conducted at 12 tertiary neurosurgical -nits (United Kingdom and Ireland). Data were collected from March 23 to July 31, 2020, inclusive. The data points collected included patient demographics, preoperative COVID-19 test results, operative modifications, and 30-day COVID-19 infection rates. -RESULTS: A total of 124 patients were included. Of the 124 patients, 116 (94%) had undergone COVID-19 testing preoperatively (transsphenoidal approach, 97 of 105 [92%]; expanded endoscopic endonasal approach, 19 of 19 [100%]). One patient (1 of 116 [0.9%]) had tested positive for COVID-19 preoperatively, requiring a delay in surgery until the infection had been confirmed as resolved. Other than transient diabetes insipidus, no other complications were reported for this patient. All operating room staff had worn at least level 2 personal protective equipment. Adapta-tions to surgical techniques included minimizing drilling, draping modifications, and the use of a nasal iodine wash. At 30 days postoperatively, no evidence of COVID-19 infection (symptoms or positive formal testing results) were found in our cohort and no mortality had occurred. -CONCLUSIONS: Preoperative screening protocols and operative modifications have facilitated endonasal neuro-surgery during the COVID-19 pandemic, with the Pituitary Society guidelines followed for most of these operations. We found no evidence of COVID-19 infection in our cohort and no mortality, supporting the use of risk mitigation strategies to continue endonasal neurosurgery in subse-quent pandemic waves.

Background The endonasal transsphenoidal approach (TSA) has emerged as the preferred approach in order to treat pituitary adenoma and related sellar pathologies. The recently adopted expanded endonasal approach (EEA) has improved access to the ventral skull base whilst retaining the principles of minimally invasive surgery. Despite the advantages these approaches offer, cerebrospinal fluid (CSF) rhinorrhoea remains a common complication. There is currently a lack of comparative evidence to guide the best choice of skull base reconstruction, resulting in considerable heterogeneity of current practice. This study aims to determine: (1) the scope of the methods of skull base repair; and (2) the corresponding rates of postoperative CSF rhinorrhoea in contemporary neurosurgical practice in the UK and Ireland. Methods We will adopt a multicentre, prospective, observational cohort design. All neurosurgical units in the UK and Ireland performing the relevant surgeries (TSA and EEA) will be eligible to participate. Eligible cases will be prospectively recruited over 6 months with 6 months of postoperative follow-up. Data points collected will include: demographics, tumour characteristics, operative data), and postoperative outcomes. Primary outcomes include skull base repair technique and CSF rhinorrhoea (biochemically confirmed and/or requiring intervention) rates. Pooled data will be analysed using descriptive statistics. All skull base repair methods used and CSF leak rates for TSA and EEA will be compared against rates listed in the literature. Ethics and dissemination Formal institutional ethical board review was not required owing to the nature of the study - this was confirmed with the Health Research Authority, UK. Conclusions The need for this multicentre, prospective, observational study is highlighted by the relative paucity of literature and the resultant lack of consensus on the topic. It is hoped that the results will give insight into contemporary practice in the UK and Ireland and will inform future studies.

A brain abscess is a focal accumulation of pus in the brain parenchyma arising from direct inoculation, contiguous spread from local anatomical structures or haematogenous seeding from a remote source of infection. It can result in significant morbidity and mortality, making early diagnosis and treatment vital. Only one fifth of patients present with the classic triad of headache, fever and focal neurological symptoms. More commonly patients show signs and symptoms of raised intracranial pressure alone, such as confusion or reduced conscious level, headache, nausea and vomiting, which can be a presentation of many intracranial pathologies. Distinguishing an abscess from other pathologies such as meningitis and tumours is crucial, as clinically these can present in similar ways, but their management and outcomes are very different. Diffusion-weighted magnetic resonance imaging brain scans can help localise the lesion and differentiate ring-enhancing lesions caused by a brain abscess from malignant tumours. Cerebral abscesses are considered a neurosurgical emergency; early stabilisation, diagnosis and management in a neurosurgical centre is important in reducing morbidity and mortality.

Introduction Craniopharyngiomas represent a unique management challenge. Aggressive surgical management has traditionally been associated with high rates of morbidity. Modern surgical techniques, and increasing practice of subtotal resection followed by radiosurgery, have reduced morbidity and mortality rates. One cause of postoperative morbidity, and indeed mortality, is aseptic meningitis from spill-out of craniopharyngioma cyst contents. We have developed a surgical technique for the management of large craniopharygngioma cysts extending into the third ventricle, to reduce this risk. Methods We describe a technique of using an epidural catheter, inserted into the working channel of a neuroendoscope, to decompress the cystic portion of a craniopharyngioma cyst before opening the cyst wall widely, preventing spill-out of large volumes of cyst content into the ventricular system. Results We have had no cases of aseptic meningitis, nor any complications, from use of the described technique. Discussion We believe that this is a safe and effective technique of decompression and fenestration of large suprasellar craniopharyngioma cysts that reduces rates of aseptic meningitis and the associated morbidity and mortality from this.

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

The Department of Neurosurgery in Oxford University Hospitals NHS Foundation Trust is a tertiary referral centre which treats approximately 1500 neurosurgery inpatients per year. Feedback from junior doctors in the General Medical Council (GMC) National Training Survey 2018 revealed low rates of trainee satisfaction. To investigate the underlying cause, an anonymous online questionnaire was designed which collected data on various aspects of junior doctors' experience in the department. Questionnaire responses from 12 out of 16 junior doctors identified problems with frequent overtime work, excessive administrative tasks, lack of protected training opportunities and variable levels of senior supervision on the ward.To reduce overtime working, the rota was re-designed to improve staffing levels in afternoons/evenings and a formal handover meeting was introduced. A departmental teaching programme with weekly seminars on the management of neurosurgical conditions and neuroanatomy was developed. This was supported by the introduction of a neurosurgery curriculum aimed specifically at junior doctors.The role of a 'Ward Registrar' was enhanced to provide structured support, supervision and training to junior doctors. This project has highlighted the value of a local questionnaire in seeking anonymised, honest feedback from junior doctors and encouraging engagement in the QI process. We anticipate that the frequent turnover of junior doctors in the department will pose a challenge for the project. It is therefore being linked to formal quality improvement training and a local peer support hub to ensure sustainability. Low levels of trainee satisfaction are likely to be multifactorial in nature and can be effectively investigated with a structured online questionnaire. By identifying key areas of concern at a local level, targeted QI projects can be designed and led by trainees, with an overall improvement in satisfaction, working hours and training opportunities.