A Cohort Analysis of Truly Incidental Low-Grade Gliomas.

BACKGROUND: Management of low-grade gliomas (LGGs) is controversial. Incidental LGGs are thought to represent an earlier stage in the disease process compared with symptomatic LGGs. With advanced imaging techniques, the discovery of these lesions is expected to increase, resulting in clinical need for further understanding of these tumors. This study aimed to identify the incidence of incidental LGGs across 2 large European neurosurgical centers and review management and survival of tumors compared with symptomatic cranial LGGs over a 5-year period. METHODS: LGGs managed during 2015-2019 at the Royal Victoria Infirmary and Münster University Hospital were retrospectively reviewed. An incidental finding was strictly defined as one discovered secondary to routine clinical or research imaging, not associated with investigation for a space-occupying lesion, with no associated symptoms. All histomolecular pathology reports were reviewed. RESULTS: Of 150 cases of World Health Organization grade II tumors identified at both centers, 82 were symptomatic, diffuse LGGs, with 20 discovered incidentally. There were 48 nondiffuse and/or pediatric tumors, which were excluded. Incidental LGGs were mostly IDH mutated and oligodendroglial with a trend toward improved overall survival and significantly increased progression-free survival compared with symptomatic LGGs (P = 0.024). In all cases, regardless of presentation, progression-free survival and overall survival were significantly improved following gross total resection versus biopsy (hazard ratio 0.45 [95% confidence interval 0.21-0.95], P = 0.037 vs. hazard ratio 0.10 [95% confidence interval 0.02-0.44], P = 0.003). CONCLUSIONS: In this study, differences in characteristics and survival between incidental and symptomatic LGGs were present, yet not significant owing to the rarity, and therefore small sample size, of incidental LGGs. Further global collaboration and development of an international glioma registry with a focus on symptoms, imaging indications (if incidental), histomolecular data, and management are needed.

A Tale of Two Cities: Residents' Operative Experience in the United Kingdom and Germany During the Coronavirus Disease 2019 Pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had a detrimental effect on residents' operative training. Our aim was to identify the proportion of procedures performed by residents across 2 neurosurgical centers (1 in the United Kingdom and 1 in Germany) during the pandemic-affected months of March 2020-May 2020, inclusive, compared with March 2019-May 2019, inclusive. METHODS: All neurosurgical procedures performed at the United Kingdom and German institutions, between March 1, 2019 and May 31, 2019 (pre-COVID months) and March 1, 2020 and May 31, 2020 (COVID months), were extracted and operative notes evaluated. Statistical analysis was performed on SPSS version 22. RESULTS: There was a statistically significant reduction in operative volume in the United Kingdom center from the pre-COVID months to the COVID months (χ2(5) = 84.917; P < 0.001) but no significant difference in the operative volume in the German center (P = 0.61). A Mann-Whitney U test showed a statistically significant difference in the volume of residents operating in the COVID months compared with pre-COVID months in both United Kingdom and German centers (P < 0.001). The average number of procedures performed by residents in the United Kingdom center as the primary surgeon decreased from 82 to 72 per month (pre-COVID vs. COVID months), whereas German residents' operating volume increased from 68 to 89 per month (pre-COVID vs. COVID months). CONCLUSIONS: The COVID-19 pandemic has significantly reduced the volume of operating by neurosurgical residents in the United Kingdom center, whereas residents in the German center performed more procedures compared with 2019. This finding may reflect variations in national practice on maintaining surgical activities and provision of critical care beds during the first wave of the pandemic.

CovidNeuroOnc: A UK multicenter, prospective cohort study of the impact of the COVID-19 pandemic on the neuro-oncology service.

BACKGROUND: The COVID-19 pandemic has profoundly affected cancer services. Our objective was to determine the effect of the COVID-19 pandemic on decision making and the resulting outcomes for patients with newly diagnosed or recurrent intracranial tumors. METHODS: We performed a multicenter prospective study of all adult patients discussed in weekly neuro-oncology and skull base multidisciplinary team meetings who had a newly diagnosed or recurrent intracranial (excluding pituitary) tumor between 01 April and 31 May 2020. All patients had at least 30-day follow-up data. Descriptive statistical reporting was used. RESULTS: There were 1357 referrals for newly diagnosed or recurrent intracranial tumors across 15 neuro-oncology centers. Of centers with all intracranial tumors, a change in initial management was reported in 8.6% of cases (n = 104/1210). Decisions to change the management plan reduced over time from a peak of 19% referrals at the start of the study to 0% by the end of the study period. Changes in management were reported in 16% (n = 75/466) of cases previously recommended for surgery and 28% of cases previously recommended for chemotherapy (n = 20/72). The reported SARS-CoV-2 infection rate was similar in surgical and non-surgical patients (2.6% vs. 2.4%, P > .9). CONCLUSIONS: Disruption to neuro-oncology services in the UK caused by the COVID-19 pandemic was most marked in the first month, affecting all diagnoses. Patients considered for chemotherapy were most affected. In those recommended surgical treatment this was successfully completed. Longer-term outcome data will evaluate oncological treatments received by these patients and overall survival.

Malignant intracerebral nerve sheath tumor in a patient with Noonan syndrome: illustrative case.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) within the neuroaxis are rare, usually arising from peripheral and cranial nerves. Even more scarce are cranial subclassifications of MPNSTs termed "malignant intracerebral nerve sheath tumors" (MINSTs). These tumors are aggressive, with a strong tendency for metastasis. With this presentation, alongside resistance to adjunctive therapy, complete excision is the mainstay of treatment, although it is often insufficient, resulting in a high rate of mortality. OBSERVATIONS: The authors report the case of an adult patient with a history of Noonan syndrome (NS) presenting with slowly progressive right-sided hemiparesis and right-sided focal motor seizures. Despite initial imaging and histology suggesting a left frontal lobe high-grade intrinsic tumor typical of a glioblastoma, subsequent molecular analysis confirmed a diagnosis of MINST. The patient's neurological condition improved after gross-total resection and adjuvant chemo-radiation; he remains on follow-up. LESSONS: MINSTs are rare neoplasms with a poor prognosis; management options are limited, with surgery being the cornerstone of treatment. Reports on rare tumors such as this will increase awareness of this particular pathology and disclose clinical experience. In this case, the authors were unable to establish a definite cause-and-effect relation between NS and MINST. Nevertheless, it remains the first reported case in the literature.

Transcortical Approach to Deep-Seated Intraventricular and Intra-axial Tumors Using a Tubular Retractor System: A Technical Note and Review of the Literature.

BACKGROUND: Retraction of white matter overlying a brain lesion can be difficult without causing significant trauma especially when using traditional methods of bladed retractors. These conventional retractors can produce regions of focal pressure resulting in contusions and areas of infarct. METHODS: In this article, we present a retrospective case series of six patients with deep-seated intraventricular and intra-axial tumors that were approached using a ViewSite Brain Access System (tubular retractor). The authors describe a unique method of creating a pathway using a dilated glove. We shall also review the relevant literature that reports this type of surgery. Cases included three cases with third ventricular colloid cysts, one case of a third ventricular arachnoid cyst, one case with a lateral ventricular neurocytoma, and a case with a deeply seated intra-axial metastatic tumor. RESULTS: Gross total resection was achieved in five cases with small residual in the central neurocytoma operation, with no documented neurological deficit in any case. One case had persistent memory problems and one case had continuing decline from the metastatic disease. CONCLUSION: The introduction of tubular-shaped retractor systems has offered the advantage of reducing retraction pressures and distributing any remaining force in a more even and larger distributed area, thus reducing the risk of previous associated morbidity while also permitting great visualization of the target lesion.

Impact of COVID-19 pandemic on surgical neuro-oncology multi-disciplinary team decision making: a national survey (COVID-CNSMDT Study).

OBJECTIVES: Pressures on healthcare systems due to COVID-19 has impacted patients without COVID-19 with surgery disproportionally affected. This study aims to understand the impact on the initial management of patients with brain tumours by measuring changes to normal multidisciplinary team (MDT) decision making. DESIGN: A prospective survey performed in UK neurosurgical units performed from 23 March 2020 until 24 April 2020. SETTING: Regional neurosurgical units outside London (as the pandemic was more advanced at time of study). PARTICIPANTS: Representatives from all units were invited to collect data on new patients discussed at their MDT meetings during the study period. Each unit decided if management decision for each patient had changed due to COVID-19. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome measures included number of patients where the decision to undergo surgery changed compared with standard management usually offered by that MDT. Secondary outcome measures included changes in surgical extent, numbers referred to MDT, number of patients denied surgery not receiving any treatment and reasons for any variation across the UK. RESULTS: 18 units (75%) provided information from 80 MDT meetings that discussed 1221 patients. 10.7% of patients had their management changed-the majority (68%) did not undergo surgery and more than half of this group not undergoing surgery had no active treatment. There was marked variation across the UK (0%-28% change in management). Units that did not change management could maintain capacity with dedicated oncology lists. Low volume units were less affected. CONCLUSION: COVID-19 has had an impact on patients requiring surgery for malignant brain tumours, with patients receiving different treatments-most commonly not receiving surgery or any treatment at all. The variations show dedicated cancer operating lists may mitigate these pressures. STUDY REGISTRATION: This study was registered with the Royal College of Surgeons of England's COVID-19 Research Group (https://www.rcseng.ac.uk/coronavirus/rcs-covid-research-group/).

Case report of a suspected pheochromocytoma co-presenting with a glioblastoma multiforme: case report and review of the literature.

The combination of a pheochromocytoma with any brain neoplasm is a rare occurrence, to our knowledge, this is the first reported case of a glioblastoma multiforme co-presenting with undiagnosed pheochromocytoma.

Minimally invasive neurosurgical access techniques to facilitate endovascular treatment of dural arteriovenous fistulae.

We report two cases of dural arteriovenous fistulae treated endovascularly, where percutaneous venous or arterial access was not suitable. In both cases, a different surgical access technique was used to allow transcranial cannulation of the appropriate venous sinus or of the varix to gain access and occlude the fistula.

The conjugation of an AQP1-directed immunotoxin in the study of site-directed therapy within the CNS.

PURPOSE: The water channel, aquaporin (AQP)1, is highly specific to the choroid plexus (CP) epithelium within the brain. It is therefore a potential target through which therapeutic agents could be selectively directed to the CP. Here we describe the conjugation of a monoclonal antibody (mAb), raised against an extra-cellular domain of AQP1, to the A chain of ricin (RCA). This reagent should allow study of a highly specific chemical lesion of the CP. METHODS: A published method was used to couple the anti-AQP1 mAb to the A chain of ricin using an SPDP cross-linker. The conjugate was purified by Superdex S-200 chromatography. Column fractions were analysed by SDS-PAGE and Western blotting. Fractions containing conjugate were assayed for cytotoxicity on rat CP cells in culture, using a WST-1 viability assay to assess cell death. RESULTS: SDS-PAGE and Western blotting demonstrated separation of conjugated anti-AQP1 mAb from unconjugated ricin by the Superdex column. Cultured rat CP cells were killed with an IC(50) of 1.81 µg/ml when exposed to the anti-AQP1 mAb-RCA conjugation reaction products. Selectivity of this reagent was demonstrated by the higher IC(50) exhibited by non-AQP1-expressing primary fibroblast cultures and cultures exposed to the reaction products from the non-specific IgG-RCA conjugation attempt. CONCLUSION: We have been able to demonstrate selective cytotoxicity in vitro of an anti-AQP1 mAb-RCA conjugate. We hope that this work will generate further interest in the use of this site-specific conjugate to target the CP in conditions such as hydrocephalus, tumours that arise from here, and other AQP1-expressing tumours.

A retrospective analysis of revision endoscopic third ventriculostomy.

PURPOSE: Endoscopic third ventriculostomy (ETV) has gained favour as an effective treatment for obstructive hydrocephalus. However, the timing of ETV failure and the long-term efficacy of revision ETV remain poorly documented. METHODS: A retrospective review was performed of patients undergoing revision ETV between 1999 and 2007. Only those patients in whom there was evidence of a good sustained clinical improvement after the initial ETV were considered candidates for ETV revision. All other patients underwent insertion of a ventriculoperitoneal shunt at the time of ETV failure. Failures that were selected for repeat ETV were subdivided into; "early" if the revision occurred within the first 3 months of the primary procedure and "late" if occurring after this. RESULTS: Ten patients underwent revision ETV (6% of all ETVs performed). Age ranged from 2 months to 32 years (mean 13.6 years). Three "early" revision ETV were performed at a mean of 1.3 months, and there were seven "late" revisions performed at a mean of 27 months. The stoma was closed in seven patients and narrowed in one patient, and a second membrane was found under the original patent stoma in a further two patients. In two patients, a third ETV procedure was performed (both at 1 month after second ETV), and the stoma was closed in both these patients. No patients have required a shunt. CONCLUSION: At last follow-up (mean 38 months), all patients remain well. Revision ETV appears a safe and effective means of managing hydrocephalus-providing there is clinical evidence that the primary procedure was initially effective. It is important to emphasise that patients with an initially successful ETV are by no means "cured".

Malignant transformation of a neurenteric cyst in the posterior fossa following complete excision.

We present a case of a 46-year-old man who developed malignant transformation of a neurenteric cyst felt to be completely removed 14 years previously. He re-presented with non-specific symptoms and hydrocephalus, and subsequent evidence of a complex lesion surrounding the lower brain stem and upper cervical cord. Histologically the original lesion was a benign neurenteric cyst, whereas the recurrent lesion showed a well differentiated adenocarcinoma. This is only the second case reported in the literature.

Bilateral extradural hematoma formation following excision of a thoracic intradural lesion.

The authors report an unusual case of a 15-year-old girl who previously underwent resection of a posterior fossa medulloblastoma, and later underwent resection of a thoracic extramedullary metastatic lesion. Her consciousness deteriorated hours after removal of her spinal metastasis. A CT head scan identified bilateral extradural cranial hematomas, which were evacuated. To the authors' knowledge, this is the first report of a patient developing bilateral acute cranial extradural hematomas following excision of a thoracic intradural lesion.

Endoscopic biopsy during third ventriculostomy in paediatric pineal region tumours.

OBJECTS: The goal of the study was to establish if endoscopic biopsy during third ventriculostomy contributes to morbidity in the management of paediatric pineal region tumours presenting with hydrocephalus. MATERIALS AND METHODS: This study was a retrospective descriptive study in patients less than 18 years of age who have presented with a pineal region tumour between 2000 and 2006. Data were obtained from case notes. Twelve patients had presented with a pineal region mass with symptomatic hydrocephalus. Of these, eight had endoscopic biopsy during third ventriculostomy. CONCLUSIONS: No mortality or permanent morbidity was seen following endoscopic biopsy. Two cases of transient worsening of pre-operative diplopia were noted. Diagnostic sensitivity for endoscopic biopsy is 75%. Tumour markers were not significantly raised in any plasma and cerebrospinal fluid samples. Endoscopic biopsy during third ventriculostomy in paediatric pineal region tumours is safe and results in good diagnostic yields. It should play an integral role in the initial management of patients in this setting.