A common tumour in a rare location: a single centre case series of cerebellar glioblastoma.

Although glioblastoma is the commonest primary brain tumour in adults, its location in the cerebellum is extremely rare. We present thirteen cases (3 female, 10 male; median age at presentation 56 [age range 21-77]) of surgically managed, histologically confirmed, primary cerebellar glioblastoma (cGB) over a 17 year period (2005-2022). Pre-operative radiological diagnosis was challenging given cGB rarity, although MRI demonstrated ring enhancement in all cases. Surgical management included posterior fossa craniectomy and debulking in 11 cases and burr hole biopsy in two. CSF diversion was necessary in four cases. No evidence of IDH or ATRX gene mutations was found when tested. Survival ranged from 1 to 22 months after diagnosis (mean 10.9 months). We also seek to understand why glioblastoma is rare in this location and discuss potential reasons for this. We hypothesise that increasing anatomical distance from germinal regions and decreased local endogenous neural stem cell activity (which has been associated with glioblastoma) may explain why glioblastoma is rare in the cerebellum. We hereby seek to add to the limited literature on cGB as this is the largest UK cGB series to date.

Olfactory neuroblastoma limited to sphenoid sinus.

Olfactory neuroblastoma (ONB) is a rare tumour of the skull base, typically originating from the nasal cavity and around the cribriform plate. We present the rare case of ONB originating from and limited to the sphenoid sinus in a 42-year old lady. Pre-operatively the lesion was thought to be a sinonasal polyp and underwent functional endoscopic sinus surgery (FESS) and total excision of the polypoid lesion. Review of histology unexpectedly revealed ONB. She underwent further surgery to ensure wide local excision was achieved with negative margins on histology, followed by radiotherapy. This is only the third reported case of ONB limited to the sphenoid sinus and the ninth reported case of primary sphenoid ONB in the literature. We review the literature pertaining with primary sphenoidal ONB here and suggest complete resection is indicated in ectopic ONB, not unlike classical ONB. There may be a role for adjuvant oncological treatments and lifelong follow up in a multidisciplinary approach is recommended.

Terson syndrome in reverse: intraventricular haemorrhage following primary intraocular haemorrhage.

Terson syndrome (TS) describes the presence of intraocular haemorrhage in patients with intracranial haemorrhage or traumatic brain injury. The aetiology of TS is controversial as an anatomical conduit between the vitreous humour and subarachnoid space remains contested. We herewith present a case of primary vitreous haemorrhage with secondary intracranial extension into the ventricles. Cranial CT demonstrates blood within the left optic nerve and chiasm but not within the subarachnoid space. This unusual phenomenon, which has not been reported before, may be described as 'Terson syndrome in reverse'. We explore mechanisms by which blood within the globe may track into the ventricular system, contextualising recent advances in the understanding of ocular-intracranial fluid transport.

Trigeminal schwannoma presenting as a gelastic seizure: no laughing matter.

We present the case of a 66 year old gentleman with trigeminal schwannoma whose only presenting feature was a single gelastic seizure. This is the first case report of pathological laughter in trigeminal schwannoma in the absence of other trigeminal, brainstem, cerebellar or other cranial nerve dysfunction.

Glioblastoma multiforme metastatic to lung in the absence of intracranial recurrence: case report.

We present the case of a 65 year old gentleman who underwent craniotomy and debulking of a left temporal glioblastoma multiforme (GBM). Post-operatively he received chemotherapy and radiotherapy with good response demonstrated on interval MRI scans. At 17 months post-diagnosis and in the absence of clinical or radiological recurrence, he presented with respiratory distress. He was found to have an exudative right-sided pleural effusion, nodular pleural thickening, a hilar mass and associated lymphadenopathy. Percutaneous pleural biopsy revealed metastatic GBM. Systemic GBM metastasis despite good response to oncological treatments and in the absence of intracranial recurrence is exceedingly rare. We review the literature concerning extra-neuraxial GBM metastasis and speculate why this phenomenon is extremely rare.

Dissection using pulsed radiofrequency energy device (PlasmaBlade) is safe and efficient in experimental revision neuromodulation implant surgery.

BACKGROUND: The use of functional neurosurgical implants has increased over the past 10 years. PlasmaBlade is an innovative electrosurgical appliance harnessing pulsed radiofrequency (RF) energy. Our aim was to assess the risk of damage to neuromodulation hardware during PlasmaBlade dissection. MATERIALS AND METHODS: A simulated setting with chicken breast threaded with different hardware and PlasmaBlade used in three configurations. . Post dissection, the wires were inspected naked eye and under an operating microscope. The induced current was assessed contemporaneously using an oscilloscope. RESULTS: Five surgeons tested the PlasmaBlade at different generator settings. Sixty dissections were undertaken. No structural damage or induced current was identified at CUT 3/4, COAG 5. At CUT 6, COAG 5 and during dissection in a perpendicular orientation with prolonged hardware contact, opacification of insulation material occurred in 15/20 dissections. There was no dissolution of insulation even at this setting. On deviation from Medtronic advice, hardware damaged occurred if one was reckless with the PlasmaBlade. CONCLUSION: When using the recommended settings and operational technique, PlasmaBlade dissection did not cause any damage to implant wiring/tubing in this simulated setting. This report seeks to add to clinical data suggesting PlasmaBlade is safe for dissection around deep brain stimulator (DBS), vagal nerve stimulator (VNS), and spinal cord stimulator (SCS) hardware.

Spontaneous regression of a large skull base meningioma: case report.

We present the case of a 58 year old lady with a large middle cranial fossa meningioma (5 cm × 4 cm in maximal dimensions) which has considerably regressed without any treatment during seven years of follow up. While the tumour had remained radiologically static for the first three years, scans from year five post-diagnosis onwards have shown shrinkage of the meningioma from a calculated volume of 36 cm3 to 11.2 cm3. There has been no intratumoral haemorrhage or infarction and no medication or exogenous hormonal effect that could account for this effect. We reviewed the literature and report that this is only the second ever case of spontaneous regression of meningioma.

Selective dorsal rhizotomy for the treatment of severe spastic cerebral palsy: efficacy and therapeutic durability in GMFCS grade IV and V children.

BACKGROUND: Selective dorsal rhizotomy (SDR) has been established as an effective surgical treatment for spastic diplegia. The applicability of SDR to the full spectrum of spastic cerebral palsy and the durability of its therapeutic effects remain under investigation. There are currently limited data in the literature regarding efficacy and outcomes following SDR in Gross Motor Function Classification System (GMFCS) IV and V patients. Intrathecal baclofen has traditionally been the surgical treatment of choice for these patients. When utilised primarily as a treatment for the relief of spasticity, it is proposed that SDR represents a rational and effective treatment option for this patient group. We report our outcomes of SDR performed on children with severe cerebral palsy (GMFCS grade IV and V). The commensurate improvement in upper as well as lower limb spasticity is highlighted. Apparent benefit to urological function following SDR in this patient group is also discussed. METHOD: A retrospective review of prospectively collected data for 54 paediatric patients with severe cerebral palsy (GMFCS IV-V) who received SDR plus specialised physiotherapy. Mean age was 10.2 years (range, 3.0-19.5). SDR guided by electrophysiological monitoring was performed by a single experienced neurosurgeon. All subjects received equivalent physiotherapy. The primary outcome measure was change to the degree of spasticity following SDR. Spasticity of upper and lower limb muscle groups were quantified and standardised using the Ashworth score. Measures were collected at baseline and at 2-, 8- and 14-month postoperative intervals. In addition, baseline and 6-month postoperative urological function was also evaluated as a secondary outcome measure. RESULTS: The mean lower limb Ashworth score at baseline was 3.2 (range, 0-4). Following SDR, significant reduction in lower limb spasticity scores was observed at 2 months and maintained at 8 and 14 months postoperatively (Wilcoxon rank, p < 0.001). The mean reduction at 2, 8 and 14 months was 3.0, 3.2 and 3.2 points respectively (range, 1-4), confirming a sustained improvement of spasticity over a 1-year period of follow-up. Significant reduction in upper limb spasticity scores following SDR was also observed (mean, 2.9; Wilcoxon rank, p < 0.001). Overall, the improvement to upper and lower limb tone following SDR-generally to post-treatment Ashworth scores of 0-was clinically and statistically significant in GMFCS IV and V patients. Urological assessment identified pre-existing bladder dysfunction in 70% and 90% of GMFCS IV and V patients respectively. Following SDR, improvement in urinary continence was observed in 71% of affected GMFCS IV and 42.8% of GMFCS V patients. No serious postoperative complications were identified. CONCLUSIONS: We conclude that SDR is safe and-in combination with physiotherapy-effectively reduces spasticity in GMFCS grade IV and V patients. Our series suggests that spastic quadriplegia is effectively managed with significant improvements in upper limb spasticity that are commensurate with those observed in lower limb muscle groups. These gains are furthermore sustained more than a year postoperatively. In light of these findings, we propose that SDR constitutes an effective treatment option for GMFCS IV and V patients and a rational alternative to intrathecal baclofen.

The Nottingham Expectation and Complication score following Surgery (NECS): an universal scale for surgical outcome audit and peer comparison.

BACKGROUND: Consultant Outcomes Publication (COP) is an NHS England initiative for promoting improvements in quality of care. However, at present outcomes are commonly expressed as mortality rates which do not necessarily reflect the performance of surgeons. We developed the Nottingham Expectation and Complication score following Surgery (NECS) to determine the success of surgical treatment from both the clinical perspective and the practical expectations agreed between surgeons and patients during the consent process. METHOD: This was a pilot study to trial the use of the NECS score. It is a simple expression of overall outcome comprising three clinical domains: S - surgical outcome, T - surgical/technical complications and M - medical complications recorded by the treating clinician, and practical outcome determined by a joint clinical/patient assessment. 107 elective neurosurgical patients were included in this prospective study. 95 completed questionnaires were included. RESULTS: 75% patients achieved the best possible treatment score (S3T3M4). Of the 25% of patients who did not achieve this ideal outcome, the most common cause was either medical deterioration 18%, or technical complications of surgery discussed during the consent process 17%, or both. Surgeons rated their outcomes as expectations exceeded in 2% of cases, met in 92%, partially met in 5% and failed in 1%. Patients rated their outcomes as expectations exceeded in 37%, met in 37%, partially met in 18%, and 5% reported that their expectations were not met or they were worse than before the operation. Bivariate correlation analysis (Pearson's r coefficient) between overall 'expectation score' of patients and surgeons showed moderate correlation with r = .25 (p = .014). CONCLUSION: NECS score can be used as an indicator to assess technical performance and patient satisfaction. It provides a more balanced quality indicator of the surgical service delivery than COP. It also offers additional advantages for auditing/planning improving care and may serve as an appraisal/revalidation tool.

Selective dorsal rhizotomy as an alternative to intrathecal baclofen pump replacement in GMFCS grades 4 and 5 children.

BACKGROUND: Conventionally, selective dorsal rhizotomy (SDR) has been reserved for ambulant children and implantation of intrathecal baclofen (ITB) pump for non-ambulant children with cerebral palsy. Rather than replacing the ITB pump in selected Gross Motor Function Classification System (GMFCS) grades 4 and 5 children, we elected to undertake SDR instead. We discuss the rationale and outcomes. OBJECTIVES: To assess if children with severe spasticity treated with long-term ITB pump would benefit from SDR as alternative procedure to replacement of ITB pump. METHOD: This study is a prospective review of ten children with severe spasticity. Indications for ITB pump replacement in 3/10 children were previous ITB pump infection and the remaining seven were nearing depletion of drug delivery system. Pre- and post-SDR mean modified Ashworth scores, assessment of urological function and survey of parent/carer satisfaction were undertaken. RESULT: Mean Ashworth score reductions post-SDR in the lower limbs and upper limbs were 2.4 and 1.70, respectively. An improvement in urological function was also noticed in 27% of patients. Overall, 90% of parents/carers felt that functional outcome with SDR was improved compared with that of ITB. CONCLUSION: SDR in comparison to ITB in this subgroup is cheaper, less intrusive by avoiding refills/replacement and found to be more effective than ITB in reducing spasticity and providing ease for nursing care. We therefore suggest that consideration should be given to SDR as an alternative in patients previously implanted with ITB systems complicated by infection or nearing end of battery life.

A Reappraisal of the Pathophysiology of Cushing Ulcer: A Narrative Review.

In 1932, Harvey Cushing described peptic ulceration secondary to raised intracranial pressure and attributed this to vagal overactivity, causing excess gastric acid secretion. Cushing ulcer remains a cause of morbidity in patients, albeit one that is preventable. This narrative review evaluates the evidence pertaining to the pathophysiology of neurogenic peptic ulceration. Review of the literature suggests that the pathophysiology of Cushing ulcer may extend beyond vagal mechanisms for several reasons: (1) clinical and experimental studies have shown only a modest increase in gastric acid secretion in head-injured patients; (2) increased vagal tone is found in only a minority of cases of intracranial hypertension, most of which are related to catastrophic, nonsurvivable brain injury; (3) direct stimulation of the vagus nerve does not cause peptic ulceration, and; (4) Cushing ulcer can occur after acute ischemic stroke, but only a minority of strokes are associated with raised intracranial pressure and/or increased vagal tone. The 2005 Nobel Prize in Medicine honored the discovery that bacteria play key roles in the pathogenesis of peptic ulcer disease. Brain injury results in widespread changes in the gut microbiome in addition to gastrointestinal inflammation, including systemic upregulation of proinflammatory cytokines. Alternations in the gut microbiome in patients with severe traumatic brain injury include colonization with commensal flora associated with peptic ulceration. The brain-gut-microbiome axis integrates the central nervous system, the enteric nervous system, and the immune system. Following the review of the literature, we propose a novel hypothesis that neurogenic peptic ulcer may be associated with alterations in the gut microbiome, resulting in gastrointestinal inflammation leading to ulceration.

Cervical catheter placement for intrathecal baclofen test dose: is it safe?

INTRODUCTION: Intrathecal baclofen testing is usually performed via a catheter inserted at the lumbar spine. However, in patients with scoliosis, the distorted anatomy and bone fusion from corrective spinal surgery obviates access at the lumbar spine. PATIENTS AND METHODS: We report a method for inserting the intrathecal catheter via a posterior cervical approach and discuss our outcome. We describe our experience in 20 patients in whom intrathecal baclofen test catheter was inserted at the lower cervical spine. Data was collected prospectively. DISCUSSION: The procedure was successful in all 20 patients. There were no complications as a result of surgery or from baclofen test dose administration via a cervical catheter. Of the 20 patients, 15 went on to have baclofen pump implantation via a cervical catheter. In one patient, subsequent pump implantation procedure was unsuccessful due to presence of extradural scar tissue. In the remaining four patients pump implantation was declined due impending corrective spinal surgery or social reasons. CONCLUSION: Our experience shows that low cervical catheter insertion for administration of a test dose of intrathecal baclofen and feasible and safe to perform via the method described.

An explanation for Terson syndrome at last: the glymphatic reflux theory.

Terson Syndrome (TS) describes the presence of intraocular hemorrhage in patients with intracranial hemorrhage, typically subarachnoid hemorrhage. Despite TS being a well-defined and frequently occurring phenomenon, its pathophysiology remains controversial. This review will present the current understanding of TS, with view to describing a contemporary and more plausible pathomechanism of TS, given recent advances in ophthalmic science and neurobiology. Previously proposed theories include a sudden rise in intracranial pressure (ICP) transmitted to the optic nerve sheath leading to rupture of retinal vessels; or intracranial blood extending to the orbit via the optic nerve sheath. The origin of blood in TS is uncertain, but retinal vessels appear to be an unlikely source. In addition, an anatomical pathway for blood to enter the eye from the intracranial space remains poorly defined. An ocular glymphatic system has recently been described, drainage of which from the globe into intracranial glymphatics is reliant on the pressure gradient between intraocular pressure and intracranial pressure. The glymphatic pathway is the only extravascular anatomical conduit between the subarachnoid space and the retina. We propose that subarachnoid blood in skull base cisterns near the optic nerve is the substrate of blood in TS. Raised ICP causes it to be refluxed through glymphatic channels into the globe, resulting in intraocular hemorrhage. We herewith present glymphatic reflux as an alternative theory to explain the phenomenon of Terson Syndrome.

Management of aneurysmal subarachnoid hemorrhage: a national survey of current practice.

OBJECTIVES: The Royal College of Physicians and American Heart Association/American Stroke Association published recommendations in 2012 for the management of aneurysmal subarachnoid hemorrhage (aSAH). This was followed by recommendations included in the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report published in November 2013. The aim of this study was to assess how many of these recommendations were being followed across the UK and Ireland 6 months after publication of the latest recommendations, and to compare current practice with the NCEPOD data collected in 2011. METHODS: We formulated a survey composed of 19 questions regarding the management of aSAH, and conducted a telephone interview with the neurosurgical registrars on call. RESULTS: 22 out of 30 centers aimed to treat ruptured aneurysms by coiling or clipping within 48 h from ictus, yet only 15 units offered regular weekend interventional neuroradiological treatment. In 9 units, all aSAH patients were routinely discussed in a multidisciplinary meeting. CONCLUSIONS: At 6 months following publication of the NCEPOD report we found that in the majority of neurosurgical units, most of the key recommendations were being met. However, in the remainder there was variability in clinical practice.

Cervical implantation of intrathecal baclofen pump catheter in children with severe scoliosis.

OBJECT: Intrathecal baclofen (ITB) pump catheter placement is traditionally performed through entry into the spinal sac at the lumbar spine. A minority of children with cerebral palsy have severe concomitant neuromuscular scoliosis. In these children, whether surgically treated or not, access to the intradural space via the lumbar spine may prove technically challenging. The authors report on a series of children in whom, for various reasons, an ITB catheter was implanted using a posterior cervical spine approach. METHODS: The records of 20 children in whom a baclofen catheter had been placed were retrospectively reviewed to assess the demographic details, indications, and outcome of this procedure. RESULTS: This approach was successful in all but one of the children in whom the procedure was abandoned given the presence of significant extradural scar tissue. Of the 20 children, 7 had previously undergone lumbar ITB catheter implantation, although the catheter was subsequently, iatrogenically transected during scoliosis surgery. Nine children had had corrective scoliosis surgery, and the fusion mass obviated access to the lumbar spinal sac. Four children had untreated scoliosis and corrective surgery was being contemplated. Complications included infection requiring explantation (2 patients), catheter migration (1 patient), intolerance to ITB (1 patient), and failure of implantation (1 patient). All patients who tolerated the ITB experienced improvement in spasticity. No complications were associated with the spinal level of catheter insertion. CONCLUSIONS: Implantation of an ITB catheter via a cervical approach is safe and feasible and should be considered in children with severe corrected or uncorrected scoliosis, and thus avoiding the lumbar spinal sac.

Spinal intramedullary arachnoid cyst.

Spinal arachnoid cysts are a relatively uncommon lesion. They may be either intra or extradural; intradural cysts being less common. Symptomatic spinal arachnoid cysts in the pediatric age group are rare. To the best of our knowledge only 2 cases of intramedullary arachnoid cysts have been reported to date. We report an unusual case of intramedullary cyst diagnosed in a 10-year-old female who presented with progressive quadriparesis. MRI scans revealed an intramedullary cystic lesion from C4 to T2. She underwent a C3 to T2 laminectomy with partial excision of the cyst. Histopathological findings confirmed the diagnosis of an arachnoid cyst. Postoperatively the patient showed dramatic recovery with marked improvement in neurological status. Arachnoid cysts should be considered in the differential diagnosis of progressive quadri / paraparesis in the pediatric age group as surgical decompression leads to marked improvement in the symptoms.