Don't make a mountain out of dermoid cysts of the anterior fontanelle.

Dermoid cysts are ectodermal inclusion lesions which can occur at the bregma, preventing complete closure of the anterior fontanelle. Various management strategies have been suggested for children presenting with such lesions. We describe the experience of managing a series of 13 consecutive patients at the University Hospital of Wales, Cardiff, including pre-operative workup, operative strategy, post operative care and follow up. Referred patients underwent a form of cross-sectional cranial imaging. All patients were given a general anaesthetic and had a small coronial incision over the lesion, large enough only to expose the lesion. Circumferential dissection of the lesion was then performed, taking particular care at the base of the lesion. We found no intra-dural or intra-sinus connection at the base of any lesion. All patients were discharged on the same day of surgery and were seen once in person or via telephone at follow-up prior to discharge. There have been no recurrences of any lesions. We conclude that these patients can be managed safely as day case procedures and discharged after single follow-up. Although a theoretical risk of intra-sinus or intra-dural connection exists, we suspect this is extremely rare.

Suspected abusive head trauma in children - when do they really need to be transferred to a neurosurgical unit?

OBJECTIVES: Transferring paediatric patients with suspected abusive head trauma (AHT) to paediatric neurosurgical centres, disrupts safeguarding investigations. Therefore, it is desirable that suspected AHTs are transferred only when clinically necessary. The aim of this study was to describe referral patterns of patients referred to a tertiary paediatric neurosurgical centre with suspected AHT, with the view of informing future transfer of AHT patients. DESIGN: A retrospective review was performed of all suspected AHT patients referred to the University Hospital of Wales between 2012 and 2021. METHODS: Rates of surgery, intubation and ventilation, radiological findings and presenting GCS were compared between referred patients and those transferred for neurosurgical care. Variables were compared between the transferred and the non-transferred groups. For categorical variables, Chi-squared tests were performed, with Fisher's exact test used where the expected count was less than 5. Odds ratios (OR) for neurosurgical transfer with radiological or clinical features at presentation were calculated. RESULTS: A total of 76 patients were referred, of which 18 were transferred for neurosurgical care. Of these, six were intubated and ventilated. Only one transferred patient required surgery, with the remainder receiving supportive care. Amongst the transferred group, 77.8% had SDHs and 68.6% had a GCS ≥ 13 at presentation. Patients with a GCS ≥ 13 and SDHs, bilateral haematomas or a history of vomiting were significantly more likely to be transferred (OR = 4.27, 95%CI 1.01-18.00, p = .05). CONCLUSIONS: Most transferred patients with suspected AHT did not receive surgical intervention. We suggest that patients should be transferred when it is likely that they will require surgery, otherwise they should stay locally in order to complete their safeguarding investigations. Immediate transfer may not be necessary for AHT patients with a GCS ≥ 13 and either vomiting, SDHs or bilateral haematomas, provided they are unlikely to require emergency surgery.

Towards improved outcome in children treated surgically for spontaneous intracranial suppuration in South Wales.

INTRODUCTION: Spontaneous central nervous system (CNS) infections in children are rare. Treatment involves surgical intervention and antibiotic therapy. We describe a single centre experience of managing this condition in South Wales. METHODS: We performed a retrospective review of surgically managed cases in our unit for patients under 18 years of age between 2008 and 2018. Data were collected regarding aetiology, location, microbiology examination, treatment and outcomes. RESULTS: Twenty-six patients were identified of which 25 case notes were available. Fifteen were male and 10 were female. Median age was 12 years (age range 0.3-17 years). Seven patients (28%) had a burr-hole aspiration and 18 (72%) underwent craniotomy. A second procedure was performed in 10 (40%) and a third procedure in two (8%). Fourteen (56%) had a brain abscess, 10 (40%) had subdural empyema (one was bilateral) and one (4%) had an extradural empyema. Fifteen (60%) had a raised WCC (>11.5 × 109/L) and 22 (88%) had a CRP of >10 mg/L at presentation. Three (12%) patients had a normal WCC and CRP at presentation. Overall, 12 (48%) were secondary to sinus infection, with the most common organism being Streptococcus. Seven (28%) were due to otitis media or mastoiditis, six (24%) had no cause identified. The mean number of CT/MRI scans was 6.7 (range 3-13). The mean follow-up period was 16.7 months (range 1-117 months). At last follow up, 19 (76%) had a GOS of 5, five (20%) had a GOS of 4 and one (12%) had GOS of 3. There were no deaths. CONCLUSIONS: In Wales, outcomes have improved over time in keeping with other paediatric neurosurgical units in England. Increased availability of imaging resources in our hospital and use of neuro-navigation for all cases in our unit as well as earlier identification of sepsis, communication with microbiologists with dedicated ward rounds and, enhanced identification of causative organisms and contemporary anti-microbials have also contributed towards the improved management of this condition.

Pre-operative dosing of dexamethasone for the management of children with posterior fossa tumours: are we getting it right?

INTRODUCTION: Posterior fossa (PF) tumours are associated with vasogenic oedema causing symptoms of raised intracranial pressure. Preoperatively this is managed with dexamethasone. To minimise steroid related complications, the lowest effective dose should be administered. No neurosurgical guidelines exist for pre-operative dosing of dexamethasone in PF tumours. METHODS: A retrospective review was performed of surgically managed cases for patients under 16 years of age between 2013 and 2018 to ascertain the initial dose of dexamethasone with symptomatic PF tumours. RESULTS: Thirty-six patients were identified of which 30 notes were available. Sixteen were male. Median age was 6 years (range 10 months - 15 years). Twenty-two (73%) were referrals from DGH and 8 (27%) presented to our neurosurgical centre. All patients presented with symptomatic PF tumours including headache (97%), vomiting (93%), gait disturbance (43%), and nystagmus (17%). Four (13%) had papilloedema. Average initial stat dexamethasone dose was 9.15 mg; 0.31 mg/kg (range 1-16.7 mg; 0.05 - 1.77 mg/kg). Stratified according to weight, average dose (and range) was 8.8 mg; 0.94 mg/kg (1-16.6 mg; 0.13 - 1.77 mg/kg) in those weighing <10 kg; 9.7 mg; 0.66 mg/kg (4-16.7 mg; 0.21 - 1.35 mg/kg) in 10-20 kg; 12.3 mg;0.52 mg/kg (8-16.7 mg; 0.27 - 0.73mg/kg) in 20-30 kg and 7.8 mg; 0.17mg/kg (2-16.7 mg; 0.0 - 0.39 mg/kg) in >30 kg up to a maximum of 16.6 mg in any 24h period. These results suggest that dosage was higher in those children weighing less. PPI was used in 24 (80%) of cases. All doses were reduced after review by the neurosurgical team and a PPI added. CONCLUSION: Pre-operative dexamethasone dosing does not always reflect the severity of clinical symptoms for PF tumours. Guidelines are required to correlate clinical symptoms with a suggested suitable dose of dexamethasone to prevent overdose and complications associated with corticosteroid use. We recommend a weight-based regimen as provided by the Food and Drug Administration. The current advice is for 0.02-0.3mg/kg/day in 3-4 divided doses.

Surgical outcomes of congenital arachnoid cysts and their association with neurodevelopmental disorders.

BACKGROUND: To evaluate the surgical outcomes of arachnoid cyst decompression in patients less than 16 years of age with an associated neurodevelopmental disorder (NDD). METHODS: A retrospective analysis of surgically treated congenital arachnoid cyst within South Wales between 2010-2019. Surgical outcomes are measured according to clinical (COG; clinical outcome score) and radiological (NOG; neuroimaging outcome score) outcomes and the complication profiles are described. The association between arachnoid cysts and NDD both in South Wales and the literature review cohort is also discussed. RESULTS: The prevalence of congenital arachnoid cysts in South Wales is 0.02% and their association with neurodevelopmental disorders among patients with a congenital arachnoid cyst is high (estimated prevalence 19%). 18 (51%) in total were surgically treated in our unit; 7 with an associated NDD. All surgical modalities showed improved clinical and radiological outcomes in those with an associated neurodevelopmental disorder. 4 (15%) patients who had endoscopic treatment, and 2 (7%) of those who underwent craniotomy had complications. No complications following cystoperitoneal shunt were seen. 4 (21%) surgically treated patients were ultimately shunted following initial treatment by endoscopy or craniotomy. CONCLUSIONS: In a cohort of patients diagnosed with a congenital arachnoid cyst in association with a neurodevelopmental disorder, all surgical treatments show improved clinical and radiological outcomes. Cystoperitoneal shunting appears to have a favourable complication profile.

The Impact of the COVID-19 Pandemic on Traumatic Brain Injury Management: Lessons Learned Over the First Year.

The COVID-19 pandemic has had widespread consequences on health care systems around the world. It resulted in extensive changes to the referral patterns, management, and rehabilitation of surgical conditions. We aimed to evaluate the effect the COVID-19 pandemic has had on traumatic brain injury (TBI) specifically. We reviewed the literature published on COVID-19 and TBI referrals, management, and rehabilitation. Significant changes were seen in the referral patterns of TBIs worldwide, explained by changes in societal behaviors and changes in the mechanism of injury. Implementation of strict infection control measures and COVID-19 screening was commonplace, with some reporting changes to operating room protocols. TBI was more likely to be conservatively managed. Rehabilitation services were restricted, with a greater shift towards telemedicine to provide rehabilitative therapy remotely.

Surgical site infection in paediatric posterior fossa surgery: does pathology matter?

OBJECTIVES: The aim of this study was to explore the rates and potential risks of surgical site infection (SSI) after posterior fossa surgery for tumour resection in children. METHODS: We retrospectively reviewed our local paediatric (age < 16 years) database for all cases of posterior fossa (PF) brain tumour surgery between November 2008 and November 2019. We collected patient demographics, tumour histology/location, and the event of postoperative surgical site infection. RESULTS: Overall, 22.1% (n=15) developed SSI out of sixty-eight children undergoing PF surgery for resection of brain tumours; 73.3% of them had a confirmed diagnosis of medulloblastoma. There was no statistically significant difference in the age (5.1 ± 0.60 vs. 6.2 ± 0.97 years; p=0.47) and duration of operation (262 vs. 253 min; p = 0.7655) between the medulloblastoma group and other tumours. Although the rate of postoperative hydrocephalus was higher in the medulloblastoma group (12.9% vs. 0%), this was not associated with increased SSI. Rates of CSF leak between the 2 groups were not different. CONCLUSION: Medulloblastoma as a pathological entity seems to carry higher risk of postoperative surgical site infection compared to other types of paediatric posterior fossa tumours. Further larger studies are required to look into this causal relationship and other risk factors that might be involved.

Is cerebrospinal fluid sampling necessary at the time of first ventriculo-peritoneal shunt insertion in paediatric patients?

OBJECTIVE: We aim to evaluate whether intraoperative cerebrospinal fluid (CSF) sampling during ventriculo-peritoneal (VP) shunt insertion can predict future VP shunt infection or guide its management. METHODS: 83 paediatric patients undergoing VP shunt insertion between February 2013 and July 2019 were retrospectively identified. Patient demographics, presence of pre-operative extra ventricular drain (EVD), pre-operative CSF results, and intra-operative CSF results were identified from patient case notes and electronic clinical databases. All included patients were followed up for a minimum of 6 months for identification of shunt infection. RESULTS: 90 VP shunt insertions were performed in 83 patients. Age at time of shunt insertion ranged from 5 days to 15.8 years (mean 44.2 months). Tumours were the most common aetiology for hydrocephalus (n = 24). 67 cases (74.4%) had intra-operative CSF samples, of which 2 revealed the presence of bacteria. Only 1 patient with intra-operative CSF sampling positive for growth developed shunt infection during follow up. Two cases developed a shunt infection despite normal intra-operative CSF results. Three cases did not have intra-operative CSF sampling but developed a shunt infection during follow up. Intra-operative CSF culture achieved 33.3% sensitivity and 98.4% specificity for predicting future shunt infection (p = 0.154). The Receiver Operator Characteristic (ROC) curve of intra-operative white cell count (WCC) and shunt infection at 6 months follow up yielded an Area Under the Curve (AUC) of 50.3%. CONCLUSION: Our results show that intraoperative CSF sampling as a method to predict future risk of shunt infection and to help inform future antibiotic prescribing is unreliable. Given an AUC of 50.3%, it is no better than chance as a diagnostic tool. Further larger studies are needed to substantiate this.

Mollaret's triangle: An important neuroanatomical territory for all clinicians.

BACKGROUND: Hypertrophic olivary degeneration is a rare condition caused by damage within the triangle of Guillain and Mollaret. We discuss the anatomical, radiological, and clinical history of this rare condition. CASE DESCRIPTION: A 32-year-old lady presented with sub-acute headache, photophobia, and dizziness. She also described facial tingling and itching over her nose, and a thirty-minute episode of slurred speech. Magnetic resonance imaging revealed a 12.1 × 11 × 7.3 mm lesion arising from the floor of the fourth ventricle [Figure 1]. Postoperative imaging confirmed complete resection of the tumor, but changes consistent with hypertrophic olivary degeneration [Figure 2a and b]. CONCLUSION: An awareness of this complication is of importance to all clinical neuroscience to prevent misdiagnosis with the occurrence of new symptoms.

Unusual cause of a painless soft tissue mass of the scalp: a rare presentation of primary intracranial neuroendocrine neoplasm.

Incidental soft tissue lumps in the scalp are a common presenting complaint in clinical practice. However, they may signify more sinister underlying pathologies. Our report examines a 63-year-old man presenting with impaired co-ordination in his left hand following a 3-month history of a painless left retroauricular scalp lump. MRI revealed a large left occipital soft tissue mass eroding through the underlying skull with infiltration into the underlying cerebellum and temporal lobe. Open biopsy confirmed a diagnosis of high-grade intracranial neuroendocrine tumour (NET). At approximately 5 months following successful tumour resection and adjuvant chemotherapy, he developed tumour recurrence and was subsequently palliated, and died at 1 year post diagnosis. Herein, we review other cases of primary intracranial NET, clinical findings, histopathological features and prognosis.

The need for hair removal in paediatric brain tumour surgery?

INTRODUCTION: Preoperative hair removal is conventional practice within neurosurgery in an attempt to maintain antisepsis. However, there is a lack of evidence to suggest that it makes a difference with regards to infection. This article aims to relate preoperative hair removal to SSIs for paediatric patients. METHODS AND MATERIALS: A retrospective analysis was conducted from a single paediatric neurosurgical database at the University Hospital of Wales. Patients were grouped according to whether they underwent preoperative hair removal or not. Findings were reviewed in light of the previously published literature. RESULTS: One hundred eighty two paediatric intracranial tumours were operated on between November 2008 and 2019. A total of twenty-six patients (14%) developed an infection post-operatively, of which meningitis was the most common (77%). Eighty-nine operations were undertaken without preoperative hair removal, of which there were a total of fifteen infections (17%). In the hair removal group, there were a total of eleven infections out of ninety-three operations (12%). Overall, the patients without hair removal had a higher infection rate when compared to those with hair removal (17 and 12% respectively), however, this result was not statistically significant (p-value 0.3989). CONCLUSION: We did not find evidence that hair removal in paediatric neurosurgery effects postoperative infection risk.

Unilateral akathisia and choreoathetosis as an unusual presentation of a frontal lobe dermoid cyst.

OBJECTIVE: To consider an unusual presentation of a frontal lobe dermoid cyst. Intracranial masses very rarely present with movement disorders. We describe a highly unusual presentation of an intracranial dermoid with unilateral choreoathetosis, akathisia and facial tics. MATERIAL: A 63-year-old man presented with left-sided akathisia and tardive dyskinesia of his upper limb, attributed to a dermoid cyst in the right frontal lobe. Resection of the cyst led to a complete resolution of his symptoms without neurological deficit. CONCLUSION: Pathogenic mechanisms of such symptoms may include compression and ischaemia of the basal ganglia and other nigrostriatal structures, as well as dysfunction of the supplementary motor area and mesolimbic dopaminergic pathways.

The efficacy of cystoperitoneal shunting for the surgical management of intracranial arachnoid cysts in the elderly: A systematic review of the literature.

BACKGROUND: Intracranial arachnoid cysts (AC) are benign, cerebrospinal fluid filled spaces within the arachnoid layer of the meninges. Neurosurgical intervention in children and young adults has been extensively studied, but the optimal strategy in the elderly remains unclear. Therefore, we performed a single center retrospective study combined with a systematic review of the literature to compare cystoperitoneal (CP) shunting with other surgical approaches in the elderly cohort. METHODS: Retrospective neurosurgical database search between January 2005 and December 2018, and systematic review of the literature using PRISMA guidelines were performed. Inclusion criteria: Age 60 years or older, radiological diagnosis of intracranial AC, neurosurgical intervention, and neuroradiological (NOG score)/clinical outcome (COG score). Data from both sources were pooled and statistically analyzed. RESULTS: Our literature search yielded 12 studies (34 patients), which were pooled with our institutional data (13 patients). CP shunts (7 patients; 15%), cyst fenestration (28 patients; 60%) and cyst marsupialisation/resection (10 patients; 21%) were the commonest approaches. Average duration of follow-up was 23.6, 26.9, and 9.5 months for each approach, respectively. There was no statistically significant association between choice of surgical intervention and NOG score (P = 0.417), COG score (P = 0.601), or complication rate (P = 0.955). However, CP shunting had the lowest complication rate, with only one patient developing chronic subdural haematoma. CONCLUSION: CP shunting is a safe and effective surgical treatment strategy for ACs in the elderly. It has similar clinical and radiological outcomes but superior risk profile when compared with other approaches. We advocate CP shunting as first line neurosurgical intervention for the management of intracranial ACs in the elderly.

Paediatric posterior fossa tumour resection rates in a small volume centre: the past decade's experience.

BACKGROUND: Paediatric brain tumour resection rates have been shown to correlate with outcome and, it is argued, are linked to operator volume and caseload. The British paediatric neurosurgery community has previously debated centralisation of paediatric neuro-oncology. At the 2018 British Paediatric Neurosurgery Group (BPNG) meeting, a commitment was made to prospectively collect tumour resection data at each Neurosurgical Unit (NSU). Here we review our prospectively-collected 10-year database of the three commonest paediatric posterior fossa tumours - astrocytomas, medulloblastomas and ependymomas. MATERIALS AND METHODS: Our primary outcome was extent of resection (EOR) on post-operative MRI scans reviewed by neuro-radiologists. Secondary outcomes comprised neurosurgical morbidity including infection, need for cerebrospinal fluid (CSF) diversion and the occurrence of posterior fossa syndrome (PFS). RESULTS: 55 children had 62 operations, where our complete resection rates for pilocytic astrocytomas, medulloblastomas and ependymomas were 77%, 79% and 63%, respectively. Both our primary and secondary outcomes were in keeping with the published literature and we discuss here some of the factors which may contribute towards favourable outcomes in a small volume centre. CONCLUSION: Our results suggest that small volume centres can expect equivalent results to larger volume NSUs with regards to paediatric brain tumour surgery. Continuing efforts nationally for data collection on resection rates and operative outcomes is a key step towards optimising management in these children.

Infected congenital cervical dermal sinuses leading to spinal cord abscess: two case reports and a review of the literature.

PURPOSE: Congenital dermal sinuses are a rare form of spinal dysraphism. The developmental defects are located along the midline neuroaxis, with sinuses in the cervical region being the least common. Congenital dermal sinuses can be associated with intraspinal infection as they act as a direct route from the skin and subcutaneous tissues into the spinal cord. METHODS: The authors present two cases of cervical dermal sinuses complicated by intramedullary abscess. Both children presented with neurological decline and febrile illness. MRI showed intraspinal abscess. Both underwent prompt surgical excision of the sinus tract, exploration of the cord and intravenous antibiotics. RESULTS: Both patients demonstrated excellent neurological recovery. CONCLUSIONS: Complete surgical excision of the sinus and tract in addition to long-term antimicrobials can yield excellent neurological outcomes. At surgery, do not expect to find pus when exploring the intramedullary component. Long-term follow-up is advocated due to potential late recurrence.

Clinical features associated with the development of hydrocephalus following TBI in the paediatric age group.

INTRODUCTION: Predictive factors for post-traumatic hydrocephalus (PTH) in adults have been elucidated but remain uncertain for children. We aimed to identify the prevalence of PTH in paediatric patients and identify clinical/radiological factors which may increase the probability of children developing PTH. METHODS: This was a retrospective study of all patients < 16 years old admitted to our unit with traumatic brain injury (TBI) between March 2013 and June 2018, 108 patients in total. Patients were classified as mild (13-15), moderate (9-12) or severe (3-8) TBI based on admission GCS. Three independent reviewers collected data from case notes. CT scans were reviewed for hydrocephalus using Evan's index. Two-tailed Fisher's exact tests with a p value < 0.05 were considered statistically significant. RESULTS: Median patient age was 7 years, and 65% were males (n = 70). PTH wasn't identified in any patients with mild/moderate TBI (n = 79). In cases of severe TBI (n = 29), three patients developed PTH requiring ventriculoperitoneal shunting (10%; p = 0.02). Radiological features which were significantly more common in the PTH group were intraventricular haemorrhage (p = 0.05) and subarachnoid haemorrhage (p = 0.03). There was also a trend towards a statistically significant association with subdural haematoma (p = 0.07). The need for other neurosurgical procedures, such as fracture elevation and craniotomy, did not increase the probability of developing with PTH (p = 0.08). DISCUSSION: The prevalence of PTH in our study is 2.7%. Factors which may be associated with a higher probability of developing PTH may include IVH, SAH, severity of TBI, and subdural haematoma. We propose a national prospective multicentre database of paediatric PTH. The data collected on prevalence, presentation, risk factors, and management could guide contemporary management and improve the outcomes of children with PTH.

Meningioma with rhabdoid features combined with meningioangiomatosis in infancy: a novel combination.

Meningioangiomatosis is a rare histologically distinct abnormality that is occasionally associated with intracranial meningioma. The rhabdoid variant of meningioma is also uncommon and is classified as a World Health Organization Grade III tumour. We report a case of meningioangiomatosis in conjunction with a meningioma with prominent rhabdoid features, in an infant male who underwent complete surgical resection of the lesion. The patient has been followed up for 6 years with no disease recurrence. To our knowledge, this is the first report in the literature describing meningioangiomatosis combined with a meningioma with rhabdoid features.

Outcomes with respect to extent of surgical resection for pediatric atypical teratoid rhabdoid tumors.

PURPOSE: To evaluate overall survival for atypical teratoid rhabdoid tumors (ATRTs) in relation to extent of surgical resection. METHODS: The neurosurgical tumor databases from three UK Pediatric centers (University Hospital of Wales, Alder Hey and Royal Manchester Children's Hospital) were analyzed. Patients with a diagnosis of ATRT were identified between 2000 and 2018. Data was collected regarding demographics, extent of resection, complications, and overall survival. RESULTS: Twenty-four patients diagnosed with ATRT underwent thirty-eight operations. The age range was 20 days to 147 months (median 17.5 months). The most common location for the tumor was the posterior fossa (nine patients; 38%). Six patients (25%) underwent a complete total resection (CTR), seven (29%) underwent a near total resection (NTR), eight (33.3%) underwent a subtotal resection (STR), and three patients (12.5%) had biopsy only. Two-thirds of patients who underwent a CTR are still alive, as of March 2019, compared to 29% in the NTR and 12.5% in the STR groups. Out of the thirty-eight operations, there were a total of twenty-two complications, of which the most common was pseudomeningocele (27%). The extent of surgical resection (p = 0.021), age at surgery (p = 0.00015), and the presence of metastases at diagnosis (0.015) significantly affected overall survival. CONCLUSIONS: Although these patients are a highly vulnerable group, maximal resection is recommended where possible, for the best chance of long-term survival. However, near total resections are likely beneficial when compared with subtotal resections and biopsy alone. Maximal surgical resection should be combined with adjuvant therapies for the best long-term outcomes.

The effect of the revised WHO classification on the incidence of grade II meningioma.

Introduction: A retrospective study over a three-year period at University Hospital of Wales (UHW) of the incidence of atypical cranial grade II meningioma both pre and post 2016 revision of The World Health Organisation (WHO) classification of tumours of the central nervous system.Subjects: All available histology from January 2015 to December 2017 of patients with cranial meningiomas.Method: Institutional online reporting system Welsh Clinical Portal to identify patients and view histology reports.Results: Overall 164 patient histology results were analysed (median age 59, age range 23-82, 74% females). There were 55 patients in 2015: 69.1% grade I, 29.1% grade II and 1.8% grade III. There were 109 patients in 2016/17; 68.8% grade I, 29.4% grade II, 1.8% grade III.Discussion: There is significant variability in the reported incidence of grade II meningioma, likely due to variation in local interpretation of diagnostic criteria. Neuropathologists at our institution have reported brain invasion as grade II prior to 2016. This was due to compelling published evidence that brain invasive meningiomas have recurrence and mortality rates similar to that of grade II meningioma as defined using other criteria. The new 2016 WHO criteria now recognise this specifically. As other institutions adapt to the amended 2016 guidelines we anticipate that there will be a greater consensus in line with our incidence rates of grade II meningioma.