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OBJECTIVE Idiopathic normal pressure hydrocephalus (iNPH) is an underdiagnosed, progressive, and disabling condition. Early treatment is associated with better outcomes and improved quality of life. In this paper, the authors aimed to identify features associated with patients with iNPH using natural language processing (NLP) to characterize this cohort, with the intention to later target the development of artificial intelligence–driven tools for early detection. METHODS The electronic health records of patients with shunt-responsive iNPH were retrospectively reviewed using an NLP algorithm. Participants were selected from a prospectively maintained single-center database of patients undergoing CSF diversion for probable iNPH (March 2008–July 2020). Analysis was conducted on preoperative health records including clinic letters, referrals, and radiology reports accessed through CogStack. Clinical features were extracted from these records as SNOMED CT (Systematized Nomenclature of Medicine Clinical Terms) concepts using a named entity recognition machine learning model. In the first phase, a base model was generated using unsupervised training on 1 million electronic health records and supervised training with 500 double-annotated documents. The model was fine-tuned to improve accuracy using 300 records from patients with iNPH double annotated by two blinded assessors. Thematic analysis of the concepts identified by the machine learning algorithm was performed, and the frequency and timing of terms were analyzed to describe this patient group. RESULTS In total, 293 eligible patients responsive to CSF diversion were identified. The median age at CSF diversion was 75 years, with a male predominance (69% male). The algorithm performed with a high degree of precision and recall (F1 score 0.92). Thematic analysis revealed the most frequently documented symptoms related to mobility, cognitive impairment, and falls or balance. The most frequent comorbidities were related to cardiovascular and hematological problems. CONCLUSIONS This model demonstrates accurate, automated recognition of iNPH features from medical records. Opportunities for translation include detecting patients with undiagnosed iNPH from primary care records, with the aim to ultimately improve outcomes for these patients through artificial intelligence–driven early detection of iNPH and prompt treatment.

External ventricular drain (EVD) and lumbar drain insertion are 2 of the most commonly performed neurosurgical procedures worldwide for acute hydrocephalus. Mechanical complications, such as obstruction or cerebrospinal fluid (CSF) leakage, are often seen and may contribute toward significant patient morbidity. Different CSF drainage methods are advocated to reduce the incidence of complications, but evidence regarding comparative effectiveness is limited.In this single-center prospective cohort study, the incidence of mechanical complications and associated interventional factors, including choice of drain, collecting system, and location, were studied in patients requiring CSF diversion for acute hydrocephalus. Univariate analyses were performed to explore trends within the data, followed by a repeated-measures mixed-effects regression to determine the independent influence of drain device on mechanical failure.Sixty-one patients required CSF diversion between January 2020 and March 2021, via 3 different drain types (lumbar drain, tunneled, and bolted EVD) and 2 collection systems (LiquoGuard 7 and AccuDrain), performed in either theater or intensive care. Twenty-one patients (39%) experienced a mechanical complication, with blockage being the most common. Multivariate analyses showed that bolted EVDs (odds ratio, 0.08; confidence interval, 0.01-0.58) and LiquoGuards (OR, 0.23; CI, 0.08-0.69) were significantly associated with fewer mechanical complications compared with tunneled EVDs and gravity-based collection systems, respectively (P ≤ 0.01).Drain device has an influence on the occurrence of EVD-related complications. These preliminary findings suggest that choosing bolted EVDs and motor-assisted drainage can reduce drain-associated mechanical failure. A randomized controlled trial comparing drain devices is required to confirm these findings.

BackgroundIntracranial pressure (ICP) is a physiological parameter that conventionally requires invasive monitoring for accurate measurement. Utilising multivariate predictive models, we sought to evaluate the utility of non-invasive, accessible MRI biomarkers in predicting ICP and their reversibility following cerebrospinal fluid (CSF) diversion.MethodsThe retrospective study included 325 adult patients with suspected CSF dynamic disorders who underwent brain MRI scans within three months of elective 24-hour ICP monitoring. Five MRI biomarkers were assessed: Yuh sella grade, optic nerve vertical tortuosity (VT), optic nerve sheath distension (ONSD), posterior globe flattening (PGF) and optic disc protrusion (ODP). The association between MRI biomarkers and 24-hour ICP was examined and reversibility of each following CSF diversion was assessed using uni- and multivariate techniques.ResultsAll five biomarkers were significantly associated with median 24-hour ICP (pConclusionsICP was predicted with clinically useful precision utilising a compact Bayesian model, offering an easily interpretable tool that utilised non-invasive imaging data. MRI biomarkers are anticipated to play a more significant role in the screening, triaging, and referral of patients with suspected CSF dynamic disorders.Key messagesBrain MRI biomarkers have been found to be correlated with cerebrospinal fluid (CSF) pressures. However, previous studies have not examined these imaging features with continuous intracranial pressure (ICP) measurements, or in patient cohorts with sizable numbers or different CSF dynamic disorders than idiopathic intracranial hypertension.In this retrospective cohort study, patients with abnormal neuroradiological markers (optic nerve sheath diameter, pituitary: sella grade, optic nerve vertical tortuosity, posterior globe flattening or optic disc protrusion) had significantly higher median 24-hour ICP readings. After adjusting for age and diagnosis, Yuh sella grade, vertical tortuosity and optic disc protrusion were significantly associated with ICP. Our multiple linear regression model was able to predict 24-hour median ICP using routine MR-imaging in those with chronic CSF disorders. Pituitary deformation resolved following CSF diversion, suggesting reversibility of certain radiological biomarkers.Brain MRIs are widely accessible and non-invasive, and are commonly used in elective patients with suspected raised ICP. Our study provides a tool incorporating simple clinico-radiological parameters for the screening, triaging, and referral of patients with suspected abnormal ICP, and our results have important implications for the diagnostic routine of patients with suspected intracranial hypertension.

Purpose The optimal management of CSF drainage in acute hydrocephalus, in particular when to initiate drain weaning, remains uncertain. This study aimed to evaluate the impact of timing and method of drain weaning on patient outcomes. Methods This prospective observational study in a large-volume tertiary neuroscience centre including all adult patients who required temporary CSF drainage for acute hydrocephalus of any cause, between January 2020 and March 2021. Contemporaneous data collection was conducted, including patient demographics, time to clamp, weaning methods, and clinical outcomes of hospital length of stay (LOS), rate of shunt insertion, drain-related infections, and mechanical complications. Univariate and multivariate statistical analyses were performed to identify the independent associations of timing-related factors. Results 69 patients were included (mean age = 59.4 years). 59% had CSF diversion for aneurysmal subarachnoid haemorrhage, and 88% had EVD drainage. The length of drainage prior to the first clamp was significantly associated with overall length of drainage (p

Background Following a diagnosis of a small unruptured intracranial aneurysm (sUIA), patients often experience psychological ailments which may be attributable to the neurovascular consultation, referral pathway, or long‐term imaging surveillance. Here, we aim to characterize the early sUIA patient journey and evaluate their psychosocial status. Methods A mixed‐methods analysis of sUIA patients attending a large tertiary neurosciences center was performed. For patients presenting to the neurovascular service in 2020, this included: (i) a thematic analysis of patient perspectives extracted from semistructured telephone interviews, (ii) a quantitative assessment of psychological status using the Hospital Anxiety and Depression Scale and (iii) an evaluation of functional independence using a customized activity of daily living questionnaire. The relationship between service or clinical factors, and Hospital Anxiety and Depression Scale subscale scores was statistically tested. Results The sUIA patient cohort (n=105) had a mean age of 56.8 years (SD=15.8, female=69). Thematic analysis of interview responses (n=33) identified 5 recurrent themes underpinning the sUIA patient experience: referral, diagnosis and information sharing, imaging surveillance, psychological impairment and coping strategies, and activities of daily living, all of which contributed to patient concerns. A total of 53.6% of patients achieved a Hospital Anxiety and Depression Scale score signifying at least mild anxiety and/or depression. Lifestyle changes most frequently affected after diagnosis included avoidance of straining‐intensive exercise, change in patterns of substance use, and work‐related performance. Multivariate analysis revealed no significant service or clinical predictors for anxiety or depression. Conclusion For some patients, an sUIA diagnosis appears to be associated, at least qualitatively, with a psychological burden. This is likely mediated through stressors related to the referral, diagnosis, neurosurgical consultation, and image surveillance. In the absence of evidence‐based guidelines regarding these aspects of the early patient journey, we offer suggestions aimed at improving both the neurovascular service and sUIA patient experience.

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating form of stroke frequently affecting young to middle-aged adults, with an unmet need to improve outcome. This special report focusses on the development of intrathecal haptoglobin supplementation as a treatment by reviewing current knowledge and progress, arriving at a Delphi-based global consensus regarding the pathophysiological role of extracellular hemoglobin and research priorities for clinical translation of hemoglobin-scavenging therapeutics. After aneurysmal subarachnoid hemorrhage, erythrocyte lysis generates cell-free hemoglobin in the cerebrospinal fluid, which is a strong determinant of secondary brain injury and long-term clinical outcome. Haptoglobin is the body’s first-line defense against cell-free hemoglobin by binding it irreversibly, preventing translocation of hemoglobin into the brain parenchyma and nitric oxide-sensitive functional compartments of cerebral arteries. In mouse and sheep models, intraventricular administration of haptoglobin reversed hemoglobin-induced clinical, histological, and biochemical features of human aneurysmal subarachnoid hemorrhage. Clinical translation of this strategy imposes unique challenges set by the novel mode of action and the anticipated need for intrathecal drug administration, necessitating early input from stakeholders. Practising clinicians (n=72) and scientific experts (n=28) from 5 continents participated in the Delphi study. Inflammation, microvascular spasm, initial intracranial pressure increase, and disruption of nitric oxide signaling were deemed the most important pathophysiological pathways determining outcome. Cell-free hemoglobin was thought to play an important role mostly in pathways related to iron toxicity, oxidative stress, nitric oxide, and inflammation. While useful, there was consensus that further preclinical work was not a priority, with most believing the field was ready for an early phase trial. The highest research priorities were related to confirming haptoglobin’s anticipated safety, individualized versus standard dosing, timing of treatment, pharmacokinetics, pharmacodynamics, and outcome measure selection. These results highlight the need for early phase trials of intracranial haptoglobin for aneurysmal subarachnoid hemorrhage, and the value of early input from clinical disciplines on a global scale during the early stages of clinical translation.

External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures. Despite this, the optimal drainage and weaning strategies are still unknown. This PRISMA-compliant systematic review and meta-analysis analysed the outcomes of patients undergoing EVD procedures, comparing continuous versus intermittent drainage and rapid versus gradual weaning. Four databases were searched from inception to 01/10/2020. Articles reporting at least 10 patients treated for hydrocephalus secondary to subarachnoid haemorrhage were included. Other inclusion criteria were the description of the EVD drainage and weaning strategies used and a comparison of continuous versus intermittent drainage or rapid versus gradual weaning within the study. Random effect meta-analyses were used to compare functional outcomes, incidence of complications and hospital length of stay. Intermittent external CSF drainage was associated with lower incidence of EVD-related infections (RR = 0.20, 95% CI 0.05–0.72, I-squared = 0%) and EVD blockages compared to continuous CSF drainage (RR = 0.45, 95% CI 0.27–0.74, I-squared = 0%). There was no clear advantage in using gradual EVD weaning strategies compared to rapid EVD weaning; however, patients who underwent rapid EVD weaning had a shorter hospital length of stay (SMD = 0.34, 95% CI 0.22–0.47, I-squared = 0%). Intermittent external CSF drainage after SAH is associated with lower incidence of EVD-related infections and EVD blockages compared to continuous CSF drainage. Patients who underwent rapid EVD weaning had a shorter hospital length of stay and there was no clear clinical advantage in using gradual weaning.

ObjectiveTo evaluate the utility of brain MRI and ophthalmic biomarkers for the prediction of intracranial hypertension, we have studied the association between 6 biomarkers and 24-hour intracranial pressure (ICP) monitoring results in 45 patients.MethodsThis single-center observational study includes patients who underwent 24-hour ICP monitoring, brain MRI (within 3 months), and ophthalmic assessment (during ICP monitoring). Six biomarkers were investigated: pituitary gland shape, vertical tortuosity of the optic nerve, distension of the optic nerve sheath, optic disc protrusion (MRI), papilledema (slit lamp biomicroscopy), and spontaneous venous pulsations (SVP, infrared video recordings).ResultsForty-five patients (mean age 39 ± 14 years, 38 women) met the inclusion criteria. All 6 biomarkers had a significant association with 24-hour ICP. Concave pituitary gland was observed with moderately elevated median ICP. Protrusion of the optic disc (MRI), papilledema, and absence of SVP were associated with the highest median ICP values. Twenty patients had raised ICP (median 24-hour ICP >5.96 mm Hg, cutoff obtained through Youden index calculation). Patients with all normal biomarkers had normal median ICP in 94% (standard error 6%) of the cases. All patients with ≥3 abnormal biomarkers had intracranial hypertension. The combination of at least 1 abnormal biomarker in MRI and ophthalmic assessments was highly suggestive of intracranial hypertension (area under the curve 0.94, 95% confidence interval 0.93–0.94)ConclusionsBrain MRI and ophthalmic biomarkers can noninvasively guide the management of patients with suspected CSF dynamics abnormalities. Patients with multiple abnormal biomarkers (≥3) or a combination of abnormal MRI and ophthalmic biomarkers are likely to have intracranial hypertension and should be managed promptly.

In the last 6 years, following the first pathological description of presumed amyloid-beta (Aβ) transmission in humans (in 2015) and subsequent experimental confirmation (in 2018), clinical cases of iatrogenic cerebral amyloid angiopathy (CAA)—attributed to the transmission of Aβ seeds—have been increasingly recognised and reported. This newly described form of CAA is associated with early disease onset (typically in the third to fifth decade), and often presents with intracerebral haemorrhage, but also seizures and cognitive impairment. Although assumed to be rare, it is important that clinicians remain vigilant for potential cases, particularly as the optimal management, prognosis, true incidence and public health implications remain unknown. This review summarises our current understanding of the clinical spectrum of iatrogenic CAA and provides a diagnostic framework for clinicians. We provide clinical details for three patients with pathological evidence of iatrogenic CAA and present a summary of the published cases to date (n=20), identified following a systematic review. Our aims are: (1) To describe the clinical features of iatrogenic CAA, highlighting important similarities and differences between iatrogenic and sporadic CAA; and (2) To discuss potential approaches for investigation and diagnosis, including suggested diagnostic criteria for iatrogenic CAA.

The insertion of bolt external ventricular drains (EVD) on the intensive care unit (ICU) has enabled rapid cranial cerebrospinal fluid (CSF) diversion. However, bolt EVDs tend to be perceived as a more challenging technique, particularly when dealing with small ventricles or when there is midline shift distorting the ventricular morphology. Furthermore, if neuronavigation guidance is felt to be necessary, this usually assumes a transfer to an operating theatre. In this technical note, we describe the use of electromagnetic neuronavigation for bolt EVD insertion on the ICU and assess the protocol’s feasibility and accuracy. Case series of neuronavigation-assisted bolt EVD insertion in ICU setting, using Medtronic Flat Emitter for StealthStation EM. Neuronavigation-guided bolt EVDs were placed at the bedside in n = 5 patients on ICU. Their widest frontal ventricular horn diameter in the coronal plane ranged from 11 to 20 mm. No procedural complications were encountered. Post-procedural CT confirmed the optimal placement of the EVDs. Electromagnetic neuronavigation is feasible at the ICU bedside and can assist the insertion of bolt EVDs in this setting. The preference for a bolt EVD to be inserted in ICU—as is standard practice at this unit—should not prohibit patients from benefitting from image guidance if required.

Intracranial pressure (ICP) refers to the pressure within the skull, which is determined by the volumes of the intracranial contents; blood, brain and cerebrospinal fluid. Monro–Kellie homeostasis stipulates that a change in the total intracranial volume is accompanied by a change in the ICP, which is more precisely described by the intracranial pressure–volume relationship. Maintenance of a relatively constant ICP is essential for maintenance of the cerebral perfusion pressure, which in turn determines global cerebral blood flow. Although the physiological process of autoregulation ensures that cerebral blood flow is tightly maintained over a range of cerebral perfusion pressures, large increases in the ICP can result in severely impaired autoregulation, meaning that cerebral blood flow may be compromised. In this review article we provide an overview of the physiological determinants of the ICP and cerebral blood flow. We go on to illustrate how pathological states can compromise physiological compensatory mechanisms in order to potentially dangerous disturbances of the ICP and cerebral blood flow.

Compared with endovascular techniques, clipping of ruptured cerebral aneurysms has been shown to associate with increased morbidity in several studies. Despite this, clipping remains the preferred option for many aneurysms. The objective of this study is to describe the reported adverse events of open repair of ruptured cerebral aneurysms and their impact on patient outcome. The PubMed, Embase and Cochrane databases were searched between June 1999 and June 2019 to identify original studies of at least 100 patients undergoing surgical repair of ruptured cerebral aneurysms and in which adverse event rates were reported. Thirty-six studies reporting adverse events in a total of 12,410 operations for repair of ruptured cerebral aneurysms were included. Surgical adverse events were common with 36 event types reported including intraoperative rupture (median rate of 16.6%), arterial injury (median rate of 3.8%) and brain swelling (median rate 5.6%). Only 6 surgical events were statistically shown to associate with poor outcomes by any author and for intraoperative rupture (the most frequently analysed), there was an even split between authors finding a statistical association with poor outcome and those finding no association. Even with modern surgical techniques, the technical demands of surgical aneurysm repair continue to lead to a high rate of intraoperative adverse events. Despite this, it is not known which of these intraoperative events are the most important contributors to the poor outcomes often seen in these patients. More research directed towards identifying the events that most drive operative morbidity has the potential to improve outcomes for these patients. Electronic supplementary material The online version of this article (10.1007/s10143-020-01312-4) contains supplementary material, which is available to authorized users.

Background The hydrodynamics of cerebrospinal fluid shunts have been described in vitro; however, knowledge on the response of intracranial pressure (ICP) to valve settings adjustments in vivo is limited. This study describes the effect of adjusting the shunt valve setting on ICP in a cohort of patients with complex symptom management. Method Single-centre retrospective observational study. Patients who underwent ICP-guided valve setting adjustments during 24-h continuous ICP monitoring, between 2014 and 2019, were included. Patients with suspected shunt malfunction were excluded. Median night ICP before and after the valve adjustments were compared (Δ night ICP). The responses of ICP to valve adjustment were divided into 3 different groups as follows: expected, paradoxical and no response. The frequency of the paradoxical response and its potential predicting factors were investigated. Results Fifty-one patients (37 females, 14 males, mean age 38 years) receiving 94 valve setting adjustments met the study inclusion criteria. Patients’ underlying conditions were most commonly hydrocephalus (47%) or idiopathic intracranial hypertension (43%). The response of ICP to valve setting adjustments was classified as ‘expected’ in 54 cases (57%), ‘paradoxical’ in 17 cases (18%) and ‘no effect’ (Δ night ICP p = 0.01 and Medtronic Strata, p = 0.02). Conclusions Paradoxical ICP changes can occur after shunt valve setting adjustments. This observation should be taken into account when performing ICP-guided valve adjustments and is highly relevant for the future development of “smart” shunt systems.

Background Given recent positive safety evidence, ventriculoatrial (VA) shunt placement may increase in popularity once more. We describe a rare case of Tricuspid regurgitation due to VA shunt catheter tip traversing the valve. Case Description A woman aged 42 years with a preexisting VA shunt was referred to this center with 3 months of orthostatic headache, nausea, and palpitations that occurred while sleeping on her right side. An echocardiogram demonstrates a VA shunt catheter in the right atrium during cardiac diastole, which traversed the tricuspid annular plane during cardiac systole. The echocardiogram revealed mild to moderate tricuspid regurgitation. She had no clinical evidence of cardiac failure or arrhythmia and had normal electrocardiogram findings. The catheter tip appeared to be adhered to the underside of the leaflets or to the chordae tendineae. Pulling the catheter tip back could therefore cause irreversible damage to the tricuspid valve. For this reason, the catheter was not removed, and the patient was referred for close follow-up with cardiologists. A literature review was performed to determine where this rare complication fits into the spectrum of VA shunt distal catheter complications, and what techniques can be done to avoid similar occurrences. Conclusions This report reiterates the importance of ensuring the tip is carefully placed within the atrium, under fluoroscopic guidance. Although rare, the described complication is difficult to manage once it has occurred.

OBJECTIVEChronic ventriculomegaly in the absence of raised intracranial pressure (ICP) is a known entity in adult hydrocephalus practice. The natural history and indication for treatment is, however, poorly defined. A highly heterogeneous group, some adults with ventriculomegaly are asymptomatic, while others have life-threatening deteriorations. The authors hypothesized that the various presentations can be subtyped and represent different stages of decompensation. A cluster analysis was performed on a cohort of patients with chronic ventriculomegaly with the aim of elucidating typical clinical characteristics and outcomes in chronic ventriculomegaly in adults.METHODSData were collected from 79 patients with chronic ventriculomegaly referred to a single center, including demographics, presenting symptoms, and 24-hour ICP monitoring (ICPM). A statistical cluster analysis was performed to determine the presence of subgroups.RESULTSFour main subgroups and one highly dissimilar group were identified. Patients with ventriculomegaly commonly have a perinatal event followed by one of four main presentations: 1) incidental ventriculomegaly with or without headache; 2) highly symptomatic presentation (including reduced consciousness) and raised ICP; 3) early presenting with symptoms of headache and nausea (with abnormal pulsatility); and 4) late presenting with features common to normal pressure hydrocephalus. Each symptomatic group has characteristic radiological features, ICPM, and responses to treatment.CONCLUSIONSCluster analysis has identified subgroups of adult patients with ventriculomegaly. Such groups may represent various degrees of decompensation. Surgical interventions may not be equally effective across the subgroups, presenting an avenue for further research. The identified subtypes provide further insight into the natural history of this lesser studied form of hydrocephalus.

Slit ventricles can be a challenging target during shunt catheter insertion. Traditionally, the frontal approach has been considered optimal for small ventricles. At this center, routine use of electromagnetic (EM) stereotactic guidance (Stealth, Medtronic, Dublin, Ireland) has enabled a parietooccipital (P-O) burr hole approach to the frontal horns. We compare shunt placement and revisions required for patients with slit ventricles who had shunts inserted via a P-O approach versus frontal shunt.We studied a retrospective cohort of patients with slit ventricles and a ventricular shunt inserted using EM guidance between 2012 and 2018. Slitlike ventricles were defined as the widest point of the lateral ventricle3 mm. Outcome measures included placement accuracy and survival using the Kaplan-Meier curve. Optimal final catheter tip location was considered to be the frontal horn of the ipsilateral lateral ventricle.Eighty-two patients (77 female, 5 male) aged 34.9 ± 10.8 years (mean ± standard deviation) had ventricular shunts inserted for idiopathic intracranial hypertension (n = 63), chiari/syrinx (n = 8), congenital (n = 10), and pseudomeningocele (n = 1). Of those identified, 35 had primary P-O shunts and 46 had frontal shunts. Overall, 94% of cases had the catheter tip sitting in the frontal horn. The P-O approach was just as accurate as the frontal approach. Eight P-O shunts and 9 frontal shunts required revision over a 60-month period. There was no significant different in shunt survival between the 2 approaches (P = 0.37).EM-guided placement has enabled the P-O approach to be as safe and with equivalent survival to frontal approach. The accuracy of shunt placement between the 2 approaches was similar.

Characterizing acute service demand is critical for neurosurgery and other emergency-dominant specialties in order to dynamically distribute resources and ensure timely access to treatment. This is especially important in the post-Covid 19 pandemic period, when healthcare centers are grappling with a record backlog of pending surgical procedures and rising acute referral numbers. Healthcare dashboards are well-placed to analyze this data, making key information about service and clinical outcomes available to staff in an easy-to-understand format. However, they typically provide insights based on inference rather than prediction, limiting their operational utility. We retrospectively analyzed and prospectively forecasted acute neurosurgical referrals, based on 10,033 referrals made to a large volume tertiary neurosciences center in London, U.K., from the start of the Covid-19 pandemic lockdown period until October 2021 through the use of a novel AI-enabled predictive dashboard. As anticipated, weekly referral volumes significantly increased during this period, largely owing to an increase in spinal referrals (p

Pharmacological prophylaxis of venous thromboembolism (VTE) requires nuanced decision-making to balance the risk of VTE against haemorrhage. This problem is compounded in neurosurgical patients, in whom postoperative intracranial haemorrhage (ICH) may be catastrophic, compared to non-neuraxial bleeding in other types of surgery. Current major guidelines recommend caution when using pharmacological prophylaxis in elective cranial surgery, but incorporate low-quality evidence and lack precise guidance on timing and duration of anticoagulation.We aimed to answer the following questions for patients undergoing elective cranial surgery: (1) when is the optimal time to initiate postoperative anticoagulation, and (2) how long should postoperative anticoagulation be continued for? In this systematic review, we screened randomised and non-randomised studies reporting original data on pharmacological VTE prophylaxis in elective cranial surgery. Outcomes of interest were VTE and ICH.Three retrospective, single-centre observational studies met eligibility criteria, with a total of 923 participants. Meta-analysis was not performed due to a high risk of bias across all studies. Through narrative synthesis, we found that patients who developed VTE were significantly more likely to receive their first postoperative dose at a later time (mean: 144 vs. 29 h,The limited evidence favours earlier initiation and shorter courses of thromboprophylactic anticoagulation. These findings are specific to patients undergoing surgery for meningioma or glioma and may not apply to other populations. Randomised controlled trials or robustly designed observational studies are necessary to establish a clearer evidence base.

After craniectomy, patients are generally advised to wear a helmet when mobilising to protect the unshielded brain from damage. However, there exists limited guidance regarding head protection for patients at rest and when being transferred or turned. Here, we emphasise the need for such protocols and utilise evidence from several sources to affirm our viewpoint. A literature search was first performed using MEDLINE and EMBASE, looking for published material relating to head protection for patients post-craniectomy during rest, transfer or turning. No articles were identified using a wide-ranging search strategy. Next, we surveyed and interviewed staff and patients from our neurosurgical centre to ascertain how often their craniectomy site was exposed to external pressure and the precautions taken to prevent this. 59% of patients admitted resting in contact with the craniectomy site, in agreement with the observations of 67% of staff. In 63% of these patients, this occurred on a daily basis and for some, was associated with symptoms suggestive of raised intracranial pressure. 44% of staff did not use a method to prevent craniectomy site contact while 65% utilised no additional precautions during transfer or turning. 63% of patients received no information about avoiding craniectomy site contact upon discharge, and almost all surveyed wished for resting head protection if it were available. We argue that pragmatic guidelines are needed and that our results support this perspective. As such, we offer a simple, practical protocol which can be adopted and iteratively improved as further evidence becomes available in this area.

Characterizing acute service demand is critical for neurosurgery and other emergency-dominant specialties in order to dynamically distribute resources and ensure timely access to treatment. This is especially important in the post-Covid 19 pandemic period, when healthcare centers are grappling with a record backlog of pending surgical procedures and rising acute referral numbers. Healthcare dashboards are well-placed to analyze this data, making key information about service and clinical outcomes available to staff in an easy-to-understand format. However, they typically provide insights based on inference rather than prediction, limiting their operational utility. We retrospectively analyzed and prospectively forecasted acute neurosurgical referrals, based on 10,033 referrals made to a large volume tertiary neurosciences center in London, U.K., from the start of the Covid-19 pandemic lockdown period until October 2021 through the use of a novel AI-enabled predictive dashboard. As anticipated, weekly referral volumes significantly increased during this period, largely owing to an increase in spinal referrals (p 0.05). Applying validated time-series forecasting methods, we found that referrals were projected to increase beyond this time-point, with Prophet demonstrating the best test and computational performance. Using a mixed-methods approach, we determined that a dashboard approach was usable, feasible, and acceptable among key stakeholders.

OBJECTIVETemporary CSF diversion through an external ventricular drain (EVD) comes with the risk of EVD-related infections (ERIs). The incidence of ERIs varies from 0.8% to 22%. ERIs increase mortality, morbidity, length of stay, and costs; require prolonged courses of antibiotics; and increase the need for subsequent permanent CSF diversion. The authors report the results of a quality improvement project designed to improve infection rates and EVD placement using simulation training in addition to a standardized perioperative care bundle. This project resulted not only in a decrease in ERIs, but also a significant improvement in surgical outcomes.METHODSA best-practice standardized perioperative approach and care bundle was approved by consensus among the senior neurosurgeons at the authors’ institution, and a standardized operative note was designed to encourage adherence to policy and improve documentation. This approach was adapted from the bundle previously described by Kubilay et al. Simulation workshops were introduced to teach safe sampling technique, administration of intrathecal drugs, and a standardized operative technique using the Rowena head surgical model. Effects of the interventions on placement, infection rates, and displacement were measured at two distinct time points over a 2-year period.RESULTSBaseline audits demonstrated satisfactory EVD placement in 74%, an infection rate of 8.5%, and displacement occurring in 20%. In the 2 years following the interventions, satisfactory placement improved to 96%, infection rate fell to 4.8%, and inadvertent displacement occurred in only 1.7%.CONCLUSIONSSimulation training and standardizing the perioperative care of patients requiring EVDs dramatically improved placement accuracy, reduced infection rates, and reduced EVD displacement rate.

External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures. Despite this, the optimal drainage and weaning strategies are still unknown. This PRISMA-compliant systematic review and meta-analysis analysed the outcomes of patients undergoing EVD procedures, comparing continuous versus intermittent drainage and rapid versus gradual weaning. Four databases were searched from inception to 01/10/2020. Articles reporting at least 10 patients treated for hydrocephalus secondary to subarachnoid haemorrhage were included. Other inclusion criteria were the description of the EVD drainage and weaning strategies used and a comparison of continuous versus intermittent drainage or rapid versus gradual weaning within the study. Random effect meta-analyses were used to compare functional outcomes, incidence of complications and hospital length of stay. Intermittent external CSF drainage was associated with lower incidence of EVD-related infections (RR = 0.20, 95% CI 0.05-0.72, I-squared = 0%) and EVD blockages compared to continuous CSF drainage (RR = 0.45, 95% CI 0.27-0.74, I-squared = 0%). There was no clear advantage in using gradual EVD weaning strategies compared to rapid EVD weaning; however, patients who underwent rapid EVD weaning had a shorter hospital length of stay (SMD = 0.34, 95% CI 0.22-0.47, I-squared = 0%). Intermittent external CSF drainage after SAH is associated with lower incidence of EVD-related infections and EVD blockages compared to continuous CSF drainage. Patients who underwent rapid EVD weaning had a shorter hospital length of stay and there was no clear clinical advantage in using gradual weaning.

For the diagnosis of subarachnoid haemorrhage (SAH), the presence of cerebrospinal fluid (CSF) xanthochromia is still considered the gold standard for patients with a thunderclap headache, in the absence of blood on brain CT scan. However, a traumatic lumbar puncture (LP) typically results in high concentrations of oxyhaemoglobin in CSF, impairing the detection of xanthochromia and preventing the reliable exclusion of SAH. In this context, the value of a repeat lumbar puncture has not yet been described.A retrospective case series of suspected SAH patients, with a negative CT scan and initial traumatic LP, managed with a repeat LP to assess for CSF xanthochromia. Clinical notes, laboratory and imaging results were reviewed.Between August 2011 and January 2020, 31 patients with suspected SAH were referred to our neurosurgical unit following negative CT and traumatic LP. A repeat LP was performed in 7 of the 31 patients, 2.4 days (±0.79 SD) after the first traumatic LP. CSF spectrophotometry analysis from repeated LP in all 7 patients was negative for xanthochromia. No adverse clinical events were recorded on average 18 months following discharge.A repeat LP performed following a traumatic tap can still yield xanthochromia-negative CSF, thereby, excluding SAH, avoiding unnecessary invasive angiography and overall promoting the safer management of these patients.

The accuracy of tunneled external ventricular drain (EVD) placement has been shown to be similar among practitioners of varying experience, but this has not yet been investigated for bolt EVDs. Tunneled and bolt EVDs are distinct techniques, and it is unclear if conclusions regarding accuracy can be inferred from one method to the other. The goal of this study was to determine whether neurosurgical experience influences the accuracy of bolt EVD placement. We performed a single-center retrospective analysis of accuracy of bolt EVD placement between 1st December 2018 and 31st May 2020, comparing the accuracy outcomes between three levels of training (junior trainees (JT); mid-grade trainees (MT); senior trainees/fellows (ST)). Accuracy was determined radiologically by two methods: Kakarla grade and by measuring the distance of the catheter tip to its optimal position (DTOP) at the foramen of Monro. Eighty-seven patients underwent insertion of bolt EVDs, of which n = 19 by JT, n = 40 by MT and n = 28 by ST, with a significant difference found between training grades in the median Kakarla grade (p = 0.0055) and in the accuracy of placement as per DTOP (p = 0.0168). In contrast to previous published results on tunneled EVDs, we demonstrate that the accuracy of bolt EVD placement is dependent on neurosurgical experience. Our results draw awareness to the fact that the bolt EVD technique can represent a challenge for less experienced practitioners and underline the importance of dedicated training to support the safe insertion of bolt ventricular catheters.

Background Multimodal monitoring of intracranial pressure and brain tissue oxygen tension (PbtO2) have been increasingly used to detect delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. At our center, patients who cannot be easily assessed clinically will undergo intracranial pressure and PbtO2 monitoring via a NEUROVENT-PTO bolt. We aimed to determine whether the Lindegaard ratios (LRs) computed from transcranial Doppler ultrasonography (TCDU) would correlate with, or can predict, the simultaneously recorded PbtO2 value. Methods Patients with aneurysmal subarachnoid hemorrhage, PbtO2 recordings from the middle cerebral artery territory, and simultaneous TCDU scans available from the ipsilateral middle cerebral artery and internal carotid artery from August 2018 to 2019 were included in the present study. The index test result was vasospasm (LR of ≥3) found on TCDU. The reference standard was the presence of regional hypoxia (PbtO2 Results A total of 28 patients (6 men and 22 women; age, 59.04 ± 13.75 years) were identified with simultaneous brain tissue oxygen and TCDU recordings available. Of the 28 patients, 7 had cerebral hypoxia (PbtO2 Conclusion We find TCDU to be specific for predicting cerebral hypoxia (measured via an intraparenchymal probe). Therefore, it could be a useful and noninvasive tool in the context of preventative DCI monitoring. However, given the low sensitivity, the lack of vasospasm on TCDU should not preclude the possibility of the presence of evolving DCI.

OBJECTIVE A better understanding of the effect of position on intracranial pressure (ICP) and compliance is important for the development of treatment strategies that can restore normal cerebrospinal fluid (CSF) dynamics. There is limited knowledge on the effect of position on intracranial compliance. In this cross-sectional study the authors tested the association of pulse amplitude (PA) with position and the day/night cycle. Additionally, they describe the postural ICP and PA changes of patients with “normal” ICP dynamics. METHODS This single-center retrospective study included patients with suspected and/or confirmed CSF dynamics abnormalities who had been examined with elective 24-hour ICP monitoring between October 2017 and September 2019. Patients had been enrolled in a short exercise battery including four positions: supine, lumbar puncture position in the left lateral decubitus position, sitting, and standing. Each position was maintained for 2 minutes, and mean ICP and PA were calculated for each position. The 24-hour day and night median ICP and PA data were also collected. Linear regression models were used to test the correlation of PA with position and day/night cycle. All linear regressions were corrected for confounders. The postural ICP monitoring results of patients without obvious ICP dynamics abnormality were summarized. RESULTS One hundred one patients (24 males and 77 females) with a mean age of 39 ± 13years (mean ± standard deviation) were included in the study. The adjusted linear regression models demonstrated a significant association of ICP with position and day/night cycle, with upright (sitting and standing) and day ICP values lower than supine and night ICP values. The adjusted linear regression model was also significant for the association of PA with position and day/night cycle, with upright and day PA values higher than supine and night PA results. These associations were confirmed for patients with and without shunts. Patients without clear ICP dynamics abnormality had tighter control of their postural ICP changes than the other patients; however, the difference among groups was not statistically significant. CONCLUSIONS This is the largest study investigating the effect of postural changes on intracranial compliance. The results of this study suggest that PA, as well as ICP, is significantly associated with posture, increasing in upright positions compared to that while supine. Further studies will be needed to investigate the mechanism behind this association.

The incidence of morbidity after cranial neurosurgery is significant, reported in up to a quarter of patients depending on methodology used. The Postoperative Morbidity Survey (POMS) is a reliable method for identifying clinically relevant postsurgical morbidity using 9 organ system domains. The primary aim of this study was to quantify early morbidity after cranial neurosurgery using POMS. The secondary aims were to identify non-POMS-defined morbidity and association of POMS with postoperative hospital length of stay (LOS).A retrospective electronic health care record review was conducted for all patients who underwent elective or expedited major cranial surgery over a 3-month period. Postsurgical morbidity was quantified on postoperative days (D) 1, 3, 5, 8, and 15 using POMS. A Poisson regression model was used to test the correlation between LOS and total POMS scores on D1, 3 and 5. A further regression model was used to test the association of LOS with specific POMS domains.A total of 246 patients were included. POMS-defined morbidity was 40%, 30%, and 33% on D1, D3, and D8, respectively. The presence of POMS morbidity on these days was associated with longer median (range) LOS: D1 6 (1 to 49) versus 4 (2 to 45) days; D3 8 (4 to 89) versus 6 (4 to 35) days; D5 14 (5 to 49) versus 8.5 (6 to 32) days; D8 18 (9 to 49) versus 12.5 (9 to 32) days (P0.05). Total POMS score correlated with overall LOS on D1 (P0.001), D3 (P0.001), and D5 (P0.001). A positive response to the "infectious" (D1, 3), "pulmonary" (D1), and "renal" POMS items (D1) were associated with longer LOS.Although our data suggests that POMS is a useful tool for measuring morbidity after cranial neurosurgery, some important morbidity items that impact on LOS are missed. A neurosurgery specific tool would be of value.

The insertion of bolt external ventricular drains (EVD) on the intensive care unit (ICU) has enabled rapid cranial cerebrospinal fluid (CSF) diversion. However, bolt EVDs tend to be perceived as a more challenging technique, particularly when dealing with small ventricles or when there is midline shift distorting the ventricular morphology. Furthermore, if neuronavigation guidance is felt to be necessary, this usually assumes a transfer to an operating theatre. In this technical note, we describe the use of electromagnetic neuronavigation for bolt EVD insertion on the ICU and assess the protocol's feasibility and accuracy.Case series of neuronavigation-assisted bolt EVD insertion in ICU setting, using Medtronic Flat Emitter for StealthStation EM.Neuronavigation-guided bolt EVDs were placed at the bedside in n = 5 patients on ICU. Their widest frontal ventricular horn diameter in the coronal plane ranged from 11 to 20 mm. No procedural complications were encountered. Post-procedural CT confirmed the optimal placement of the EVDs.Electromagnetic neuronavigation is feasible at the ICU bedside and can assist the insertion of bolt EVDs in this setting. The preference for a bolt EVD to be inserted in ICU-as is standard practice at this unit-should not prohibit patients from benefitting from image guidance if required.

Objective Ventriculoperitoneal (VP) shunt surgery is a common and effective treatment for hydrocephalus and cerebrospinal fluid disorders. Infection remains a major cause of morbidity and mortality after a VP shunt. There is evidence that a deep skin flora microbiome may have a role to play in post-operative infections. In this technical note, we present a skin preparation technique that addresses the issue of the skin flora beyond the initial incision. Methods The patient is initially prepped, as standard, with. a single layer of 2% CHG+70% isopropyl alcohol. The novel stage is the 'double incision' whereby an initial superficial incision receives a further application of povidone-iodine prior to completing the full depth incision. Results Of the 84 shunts inserted using the double-incision method (September 2015 to September 2016), only one developed a shunt infection. Conclusion The double incision approach to skin preparation is a unique operative stage in VP shunt surgery that may have a role to play in reducing acute shunt infection.

Tinnitus is a symptom commonly associated with idiopathic intracranial hypertension (IIH) that can have a profound effect on quality of life. We aim to determine tinnitus symptom response after dural venous sinus stenting (DVSS) or CSF diversion with a shunt, in patients with both pulsatile (PT) and non-pulsatile tinnitus (NPT). Single-centre cohort of IIH patients (2006–2016) who underwent 24-h ICP monitoring (ICPM). An un-paired t test compared ICP and pulse amplitude (PA) values in IIH patients with PT vs. NPT. We identified 59 patients with IIH (56 F:3 M), mean age 32.5 ± 9.49 years, 14 of whom suffered from tinnitus. Of these 14, seven reported PT and seven reported NPT. Patients with tinnitus had a mean 24-h ICP and PA of 9.09 ± 5.25 mmHg and 6.05 ± 1.07 mmHg respectively. All 7 patients with PT showed symptom improvement or resolution after DVSS (n = 4), secondary DVSS (n = 2) or shunting (n = 1). In contrast, of the 7 with NPT, only 1 improved post intervention (DVSS), despite 2 patients having shunts and 5 having DVSS. NPT and PT were equally as common in our group of IIH patients. DVSS appears to be an effective management option for IIH patients with a clear history of pulsatile tinnitus. However, non-pulsatile tinnitus was more persistent and did not respond well to either DVSS or CSF diversion.

Background Complex hydrocephalus affecting lateral and fourth ventricles separately is occasionally managed with cerebrospinal fluid diversion via supratentorial and infratentorial ventricular catheters. The optimal configuration to reduce complications is currently unknown in adults. We describe a consistently similar clinical presentation of patients with complex hydrocephalus and a fourth ventricle separately drained by infratentorial shunt insertion. Methods This was a retrospective single-center case series. Medical notes were reviewed for clinical presentation, brain imaging, and neurophysiologic tests results. All patients underwent intracranial pressure monitoring (ICPM). Outcomes were determined by ventricular appearance on brain imaging computed tomography and symptomatic improvements postoperatively. Results Five adult patients referred to the hydrocephalus service had separate infratentorial and supratentorial shunt systems. A common clinical presentation was observed, including lower motor neuron facial palsy (confirmed with electrophysiology), ophthalmoplegia, dysarthria, impaired gait headache, and nausea. We refer to this as transtentorial distortion syndrome. Twenty-four-hour ICPM demonstrated clear low pressures. All patients underwent shunt revision connecting the transtentorial shunts via a Y-connector and the addition of a distal valve. All subjects had improved ventricular appearance on computed tomography scans post revision, and normalization of ICPM was observed. In the follow-up period of 6 months, no patient required further shunt revision. Conclusion To prevent transtentorial distortion syndrome, supratentorial and infratentorial shunt constructs in adults with encysted fourth ventricles should be similar to the shunt systems widely known in the pediatric population with Dandy-Walker syndrome (i.e., joint output to a single valve distal to the connection of the 2 proximal drainage catheters).

Background Idiopathic normal pressure hydrocephalus (INPH) has no reliable biomarker to assist in the selection of patients who could benefit from ventriculo-peritoneal (VP) shunt insertion. The neurodegenerative markers T-tau and Aβ1-42 have been found to successfully differentiate between Alzheimer’s disease (AD) and INPH and therefore are candidate biomarkers for prognosis and shunt response in INPH. The aim of this study was to test the predictive value of cerebrospinal fluid (CSF) T-tau and Aβ1-42 for shunt responsiveness. In particular, we pay attention to the subset of INPH patients with raised T-tau, who are often expected to be poor surgical candidates. Methods Single-centre retrospective analysis of probable INPH patients with CSF samples collected from 2006 to 2016. Index test: CSF levels of T-tau and Aβ1-42. Reference standard: postoperative outcome. ROC analysis assessed the predictive value. Results A total of 144 CSF samples from INPH patients were analysed. Lumbar T-tau was a good predictor of post-operative mobility (AUROC 0.80). The majority of patients with a co-existing neurodegenerative disease responded well, including those with high T-tau levels. Conclusion INPH patients tended to exhibit low levels of CSF T-tau, and this can be a good predictor outcome. However levels are highly variable between individuals. Raised T-tau and being shunt-responsive are not mutually exclusive, and such patients ought not necessarily be excluded from having a VP shunt. A combined panel of markers may be a more specific method for aiding selection of patients for VP shunt insertion. This is the most comprehensive presentation of CSF samples from INPH patients to date, thus providing further reference values to the current literature.

Cerebral aneurysms in complex anatomical locations and intraoperative rupture of aneurysms are challenging for neurosurgeons and anaesthetists alike. Mechanical and non-mechanical methods to reduce blood flow into aneurysms are well-recognised techniques to facilitate aneurysm exclusion from the circulation. Mechanical methods like temporary clipping of parent arteries, carotid artery ligation and endovascular balloon occlusion are commonly used in clinical practice. However, non-mechanical techniques such as rapid ventricular pacing and adenosine-induced cardiac standstill with hypotension are still emerging strategies. The aim of this study is to report our units’ experience in the use of adenosine in aneurysm clipping and arteriovenous malformation (AVM) resection and review the literature. The records of all patients who had adenosine-assisted clipping of intracranial aneurysms and AVM resections in our institute between November 2015 and December 2016 were extracted from prospectively maintained database. The following data were collected: patient demographics, comorbidities, size and location of the aneurysms or AVM, number of boluses and total dose of adenosine administered, duration of cardiac standstill and hypotension (systolic blood pressure

To improve quality of care for patients presenting with chronic subdural haematoma (CSDH) by introducing a multi-disciplinary integrated care pathway.CSDH is a common neurological condition. Incidence rises with age and currently affects around 58/100 000 people over 70 years. Six-month mortality is high (26%), however integrated care pathways have been shown to improve patient outcomes in other surgical subspecialties.A baseline retrospective audit completed in 2012 identified areas for improvement in patient management. Stakeholder meetings were held with subsequent development and implementation of a patient care pathway. A post-implementation prospective audit was completed between January and October 2015.patient demographics, medical co-morbidities, use of anti-platelet and anti-coagulant medication, timing of surgery, length of hospital stay, morbidity and mortality data, and reaccumulation rate.Patient groups were similar with a high incidence of multi-morbidity. The key areas targeted for improvement included enhanced pre-operative optimisation and time to surgery. Implementation of the patient care pathway significantly increased the number of patients undergoing surgery within 24 hours of admission (43% vs. 75%, p = 0.0006) but length of hospital stay did not change. Operative morbidity and mortality remained similar and there was no significant difference in CSDH reaccumulation rate.Our patient care pathway appears to have improved pre-operative care and significantly increased the proportion of patients undergoing surgery within 24 hours of admission. Difficulties were encountered with changing existing practice. Prospective research is required to demonstrate the full benefits, which may include a reduction in health and social care costs.

The ever present need to balance over drainage with under drainage in hydrocephalus has required innovations including adjustable valves with antigravity devices. These are activated in the vertical position to prevent siphoning. We describe a group of bedridden patients who presented with unexplained under drainage caused by activation of antigravity shunt components produced by peculiar head/body position. Retrospective single centre case series of hydrocephalus patients, treated with ventriculo-peritoneal (VP) shunt insertion between April 2014 - February 2016. These patients presented with clinical and radiological under drainage syndrome. Medical notes were reviewed for clinical picture and outcome. Radiological studies were reviewed assessing shunt placement and ventricular size. Seven patients presented with clinical and radiological under drainage syndrome. A consistent posturing of long term hyper-flexion of the neck whilst lying supine was observed. All patients had similar shunt construct (adjustable Miethke ProGAV valve and shunt assistant anti-gravity component). In each of those patients a hypothesis was formulated that neck flexion was activating the shunt assistance anti-gravity component in supine position. Five patients underwent shunt revision surgery removing the shunt assistant device from the cranium and adding an anti-gravity component to the shunt system at the chest. One had the shunt assistant completely removed and one patient was managed conservatively with mobilisation. All patients had clinical and radiological improvement. Antigravity shunt components implanted cranially in bedridden hydrocephalus patients will produce underdrainage due to head flexion induced anti-gravity device activation. In these patients, anti-gravity devices should be placed at the chest. Alternatively, special nursing attention should be paid to head-trunk angle.

Raised white cell count (WCC) in lumbar CSF is a commonly used marker of meningitis. The effect of cranial neurosurgery per se on lumbar WCC is not established. At this single centre, many patients undergo ICPM followed by lumboperitoneal shunt (LPS), with lumbar CSF WCC samples taken during insertion. We aimed to determine the effect of ICP bolt insertion on lumbar CSF WCC. We undertook a retrospective analysis of lumbar CSF samples in patients who had recently undergone 24-h ICPM. Thirty-three patients (16F:7M) aged 43.31 ± 12.1 years (mean ± SD) had lumbar CSF samples after ICPM. Fourteen had CSF sampled within 6 weeks and 19 after 6 weeks of ICPM. Twenty-five samples were taken during LPS insertion, 5 during lumbar drainage/puncture and 3 during LPS revision. All 33 patients were afebrile at the point of CSF sampling. The mean lumbar WCC within 6 weeks of ICPM was significantly higher than the mean lumbar WCC after 6 weeks, being 15.4 ± 18.0 and 2.32 ± 1.79 cells/microlitre respectively respectively. There was no significant increase in RBC. In patients with raised CSF WCC, 60% of raised WCC were predominantly lymphoctyes and 40% predominantly neutrophils. Only one patient grew an organism (S. aureus). We conclude that lumbar CSF WCC can be raised following minor intracranial surgery, despite no clinical sign of infection. We caution against using lumbar CSF WCC values independently as the only marker of infection following neurosurgery.

Background Patients with normal pressure hydrocephalus (NPH) are often elderly, frail and affected by multimorbidity. Treatment is surgical with cerebrospinal diversion shunts. The selection of patients that are of an acceptable level of risk to be treated surgically has been a matter of debate for years and has deprived some patients of life-changing surgery. The aim of this service evaluation was to investigate the preoperative risk factors and early postoperative morbidity of patients with NPH using a standardized postoperative survey. Materials and methods Consecutive NPH patients admitted for neurosurgical management of NPH between May 2017 and May 2018 were included in this prospective service evaluation. In addition to the collection of traditional outcome measures, the cardiac version of the Postoperative Morbidity Survey (C-POMS) was conducted on postoperative days 4, 7, and 10 to identify postoperative morbidity. Results Eighty-eight patients (63 males, age mean±SD, 75±7 y) underwent 106 surgical procedures (61 lumbar drains, 45 ventriculoperitoneal shunts). There was no 30-day mortality and no unexpected return to the operating room or admission to intensive care unit. There was 1 conservatively managed surgical complication. On postoperative day 4, the C-POMS identified no postoperative morbidity in 72% of the patients, and mild morbidity (postoperative nausea and mobility issues) in 28%. There was a delay in discharge in 50% of the patients with no postoperative morbidity on day 4, highlighting areas of our service requiring improvement. Conclusions Early postoperative outcomes of NPH patients are good after both ventriculoperitoneal shunt insertion and lumbar drainage. This evaluation provides initial evidence on the utility of the C-POMS as a service evaluation tool in the standardized assessment postoperative outcomes in neurosurgery patients.

BACKGROUND: Assessment of spontaneous venous pulsation (SVP) is commonly undertaken to help determine whether intracranial pressure (ICP) is elevated. Previous studies using direct ophthalmoscopy or slit-lamp assessments have found that SVP is not observed in 67%-81% of subjects with normal ICP, and that interobserver agreement when grading SVP is poor. // METHODS: Patients (n = 105) undergoing clinically indicated retinal OCT scans, who were all believed to have normal ICP, had 10-second infrared video recordings performed with the Heidelberg Spectralis OCT system (Heidelberg Engineering GmbH, Heidelberg, Germany). The presence and amplitude of SVP in each video was independently graded by 2 neuro-ophthalmologists. // RESULTS: The 2 observers found SVP present in 97% and 98% of right eyes and in one or both eyes in 99% and 100% of subjects. Interobserver agreement was high (Cohen's kappa 0.82 for right eyes). Optic discs with a smaller cup had a significantly lower SVP amplitude (Spearman's rho = 0.22, P = 0.02). // CONCLUSIONS: Infrared video is widely available in eye clinics by the use of OCT imaging systems and is substantially more sensitive in detecting SVP than traditional assessments using ophthalmoscopy. SVP is absent in as few as 1% of people with presumed normal ICP.

Purpose of review This article describes the physiology of cerebrospinal fluid (CSF). We review current evidence and new concepts relating to CSF physiology with respect to CSF secretion, circulation and resorption and we highlight key pathophysiological associations including the relationship between CSF and intracranial pressure. Recent findings CSF secretion occurs primarily via the choroid plexus. Various transport mechanisms facilitate CSF secretion but the role Aquaporins play in this process is a recent discovery and an area of ongoing research. CSF circulation is a dynamic process but the importance of the perivascular 'Glymphatic system' and extraarachnoidal pathways of resorption are relatively new concepts. Summary CSF physiology is dependent on various interacting factors and is critical for normal brain development and function.

Importance Spontaneous intracranial hypotension (SIH) is a highly disabling but often misdiagnosed disorder. The best management options for patients with SIH are still uncertain. Objective To provide an objective summary of the available evidence on the clinical presentation, investigations findings, and treatment outcomes for SIH. Data Sources Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline–compliant systematic review and meta-analysis of the literature on SIH. Three databases were searched from inception to April 30, 2020: PubMed/MEDLINE, Embase, and Cochrane. The following search terms were used in each database:spontaneous intracranial hypotension,low CSF syndrome,low CSF pressure syndrome,low CSF volume syndrome,intracranial hypotension,low CSF pressure,low CSF volume,CSF hypovolemia,CSF hypovolaemia,spontaneous spinal CSF leak,spinal CSF leak, andCSF leak syndrome. Study Selection Original studies in English language reporting 10 or more patients with SIH were selected by consensus. Data Extraction and Synthesis Data on clinical presentation, investigations findings, and treatment outcomes were collected and summarized by multiple observers. Random-effect meta-analyses were used to calculate pooled estimates of means and proportions. Main Outcomes and Measures The predetermined main outcomes were the pooled estimate proportions of symptoms of SIH, imaging findings (brain and spinal imaging), and treatment outcomes (conservative, epidural blood patches, and surgical). Results Of 6878 articles, 144 met the selection criteria and reported on average 53 patients with SIH each (range, 10-568 patients). The most common symptoms were orthostatic headache (92% [95% CI, 87%-96%]), nausea (54% [95% CI, 46%-62%]), and neck pain/stiffness (43% [95% CI, 32%-53%]). Brain magnetic resonance imaging was the most sensitive investigation, with diffuse pachymeningeal enhancement identified in 73% (95% CI, 67%-80%) of patients. Brain magnetic resonance imaging findings were normal in 19% (95% CI, 13%-24%) of patients. Spinal neuroimaging identified extradural cerebrospinal fluid in 48% to 76% of patients. Digital subtraction myelography and magnetic resonance myelography with intrathecal gadolinium had high sensitivity in identifying the exact leak site. Lumbar puncture opening pressures were low, normal (60-200 mm H2O), and high in 67% (95% CI, 54%-80%), 32% (95% CI, 20%-44%), and 3% (95% CI, 1%-6%), respectively. Conservative treatment was effective in 28% (95% CI, 18%-37%) of patients and a single epidural blood patch was successful in 64% (95% CI, 56%-72%). Large epidural blood patches (>20 mL) had better success rates than small epidural blood patches (77% [95% CI, 63%-91%] and 66% [95% CI, 55%-77%], respectively). Conclusions and Relevance Spontaneous intracranial hypotension should not be excluded on the basis of a nonorthostatic headache, normal neuroimaging findings, or normal lumbar puncture opening pressure. Despite the heterogeneous nature of the studies available in the literature and the lack of controlled interventional studies, this systematic review offers a comprehensive and objective summary of the evidence on SIH that could be useful in guiding clinical practice and future research.

Selecting probable idiopathic normal pressure hydrocephalus (INPH) patients for shunt insertion presents a challenge because of coexisting comorbidities and other conditions that could mimic NPH. The characteristic appearance of DESH (Disproportionately Enlarged Subarachnoid Space Hydrocephalus) on brain imaging has been shown to have a high positive predictive value in identifying shunt responsive INPH patients (SINPHONI trial). However, the negative predictive value of this radiological sign was not clearly demonstrated. The aim of the present study was to calculate the negative predictive value of the DESH sign.A single centre study of probable INPH patients, who underwent ventriculoperitoneal (VP) shunt insertion. Shunt responsive INPH patients were identified as those having improvement in their walking speed, neuropsychological assessment and continence one year post operatively. Preoperative images were reviewed for DESH sign. Negative and Positive Predictive Values (NPV and PPV) of DESH sign were determined post analysis.A total of 103 probable INPH patients were included (31 were DESH positive (30%) and 72 were DESH negative (70%)). A total of 78 patients showed measurable improvement one year post shunt insertion (76%); 24 (31%) of these patients were DESH positive and 54 (69%) were DESH negative (p=0.001). Therefore, the DESH sign had an estimated PPV of 77% and NPV of 25%.DESH sign demonstrates a low negative predictive value. We conclude that DESH negative patients should still undergo prognostic tests for iNPH, such as an extended lumbar drainage protocol, and should not be excluded from shunt insertion.

Cerebrospinal fluid (CSF) leak following spinal surgery is a relatively common surgical complication. A disturbance in the underlying CSF dynamics could be the causative factor in a small group of patients with refractory CSF leaks that require multiple surgical repairs and prolonged hospital admission. A retrospective case series of patients with persistent post spinal surgery CSF leak referred to the hydrocephalus service for continuous intracranial pressure (ICP) monitoring. Patients’ notes were reviewed for medical history, ICP data, radiological data, and subsequent management and outcome. Five patients (two males/three females, mean age, 35.4 years) were referred for ICP monitoring over a 12-month period. These patients had prolonged CSF leak despite multiple repair attempts 252 ± 454 days (mean ± SD). On ICP monitoring, all five patients had abnormal results, with the mean ICP 8.95 ± 4.41 mmHg. Four had abnormal pulse amplitudes, mean 6.15 mmHg ± 1.22 mmHg. All five patients underwent an intervention. Three patients underwent insertion of ventriculoperitoneal (VP) shunts. One patient had venous sinus stent insertion and one patient underwent medical management with acetazolamide. All five of the patients’ CSF leak resolved post intervention. The mean time to resolution of CSF leak post intervention was 10.8 ± 12.9 days. Abnormal cerebrospinal fluid dynamics could be the underlying factor in patients with a persistent and treatment-refractory CSF leak post spinal surgery. Treatments aimed at lowering ICP may be beneficial in this group of patients. Whether abnormal pressure and dynamics represent a pre-existing abnormality or is induced by spinal surgery should be a subject of further study.