Robotically facilitated parafasicular microsurgery to a brain arteriovenous malformation in a paediatric patient.

PURPOSE: We report what we believe is the first application of robotically constrained image-guided surgery to approach a fistulous micro-arteriovenous malformation in a highly eloquent location. Drawing on institutional experience with a supervisory-control robotic system, a series of steps were devised to deliver a tubular retractor system to a deeply situated micro-arteriovenous malformation. The surgical footprint of this procedure was minimised along with the neurological morbidity. We hope that our contribution will be of assistance to others in integrating such systems given a similar clinical problem. CLINICAL PRESENTATION: A right-handed 9-year old girl presented to her local emergency department after a sudden onset of severe headache accompanied by vomiting. An intracranial haemorrhage centred in the right centrum semiovale with intraventricular extension was evident and she was transferred urgently to the regional paediatric neurosurgical centre, where an external ventricular drain (EVD) was sited. A digital subtraction angiogram demonstrated a small right hemispheric arteriovenous shunt irrigated by peripheral branches of the middle cerebral artery & a robotically facilitated parafasicular microsurgical approach was performed to disconnect the arteriovenous malformation. CONCLUSION: We describe the successful microsurgical in-situ disconnection of a deeply-situated, fistulous micro-AVM via a port system itself delivered directly to the target with a supervisory-control robotic system. This minimised the surgical disturbance along a relatively long white matter trajectory and demonstrates the feasibility of this approach for deeply located arteriovenous fistulae or fistulous AVMs.

A survey of the radiological follow-up of unruptured intracranial aneurysms in the United Kingdom.

OBJECTIVE: Unruptured intracranial aneurysms (UIA) are common. For many the treatment risks outweigh their risk of subarachnoid haemorrhage and patients undergo surveillance imaging. There is little data to inform if and how to monitor UIAs resulting in widely varying practices. This study aimed to determine the current practice of unruptured UIA surveillance in the United Kingdom. METHODS: A questionnaire was designed to address the themes of surveillance protocols for UIA including when surveillance is initiated, how frequently it is performed, and when it is terminated. Additionally, how aneurysm growth is managed and how clinically meaningful growth is defined were explored. The questionnaire was distributed to members of the British Neurovascular Group using probability-based cluster and non-probability purposive sampling methods. RESULTS: Responses were received from 30 of the 30 (100.0%) adult neurosurgical units in the United Kingdom of which 27 (90.0%) routinely perform surveillance for aneurysm growth. Only four units had a unit policy. The mean patient age up to which a unit would initiate follow-up of a low-risk UIA was 65.4 ± 9.0 years. The time points at which imaging is performed varied widely. There was an even split between whether units use a fixed duration of follow-up or an age threshold for terminating surveillance. Forty percent of units will follow-up patients more than 5 years from diagnosis. The magnitude in the change in size that was felt to constitute growth ranged from 1 to 3mm. No units routinely used vessel wall imaging although 27 had access to 3T MRI capable of performing it. CONCLUSIONS: There is marked heterogeneity in surveillance practices between units in the United Kingdom. This study will help units better understand their practice relative to their peers and provide a framework forplanning further research on aneurysm growth.

Non-linear models of species' responses to environmental and spatial gradients.

Species' responses to broad-scale environmental or spatial gradients are typically unimodal. Current models of species' responses along gradients tend to be overly simplistic (e.g., linear, quadratic or Gaussian GLMs), or are suitably flexible (e.g., splines, GAMs) but lack direct ecologically interpretable parameters. We describe a parametric framework for species-environment non-linear modelling ('senlm'). The framework has two components: (i) a non-linear parametric mathematical function to model the mean species response along a gradient that allows asymmetry, flattening/peakedness or bimodality; and (ii) a statistical error distribution tailored for ecological data types, allowing intrinsic mean-variance relationships and zero-inflation. We demonstrate the utility of this model framework, highlighting the flexibility of a range of possible mean functions and a broad range of potential error distributions, in analyses of fish species' abundances along a depth gradient, and how they change over time and at different latitudes.

Current decision support tools fail to agree or predict therapeutic decisions in a single cohort of unruptured intracranial aneurysms.

BACKGROUND: There is limited evidence to direct the management of unruptured intracranial aneurysms. Models extrapolated from existing data have been proposed to guide treatment recommendations. The aim of this study is to assess whether a consensus-based treatment score (UIATS) or rupture rate estimation model (PHASES) can be used to benchmark UK multi-disciplinary team (MDT) practice. METHODS: Prospective data was collected on a consecutive series of all patients with unruptured intracranial aneurysms (UIAs) presenting to a major UK neurovascular centre between 2012 and 2015. The agreement between the UIATS and PHASES scores, and their sensitivity and specificity in predicting the real-world MDT outcome were calculated and compared. RESULTS: A total of 366 patients (456 aneurysms) were included in the analysis. The agreement between UIATS and MDT recommendation was low (weighted kappa 0.26 [95% CI 0.19, 0.32]); sensitivity and specificity were also low at 36% and 52% respectively. Groups that the MDT allocated to treatment, equipoise or no treatment had significantly different PHASES scores (p = 0.004). There was no significant difference between the two scores when predicting patients for whom MDT outcome was to recommend aneurysm treatment, but the UIATS score was superior in predicting patients who received an MDT recommendation of 'treatment-equipoise', or 'not-for-treatment' (AUC of 0.73 compared to 0.59 for PHASES). CONCLUSIONS: The models studied failed to agree with the consensus view of multi-disciplinary team in a major neurovascular centre. We conclude that decision support tools such as the UIATS and PHASES scores should not be blindly introduced in respective institutions without prior internal validation, as they may not represent the local reality.

Occam or Hickham? The diagnostic dilemma of an inflammatory brain lesion in the setting of pulmonary aspergillosis and previous neurosurgery.

INTRODUCTION: Occam's Razor is a precept which invites one to consider the simplest and most unifying diagnosis as correct. In the modern era, clinical diagnosis remains critical in selecting appropriate therapies yet grows ever more complex with increased information from diagnostic technologies, but not always with sufficient granularity to answer the clinical question with certainty. We present an example of this dilemma in a patient with complex partial seizures on a background of pulmonary aspergillosis and historic clipping of a middle cerebral artery (MCA) aneurysm. CASE DESCRIPTION: A 69-year-old female presented with progressive headaches, temporal lobe seizures, poor short-term memory and weight loss. She had suffered a subarachnoid haemorrhage 22 years earlier requiring surgical repair of a right MCA aneurysm. She was treated for breast cancer in 2006 followed by pulmonary aspergilloma in 2014 for which systemic antifungals were discontinued due to toxicity. Imaging revealed a right temporal inflammatory lesion adjacent to the aneurysm clip. Gastrointestinal toxicity and haemoptysis complicated the clinical and radiological response to systemic steroids. Cerebral aspergillosis was considered given her medical history despite an equivocal fungal screen, but intolerable side effects negated the continued use of systemic antifungals. Surgical exploration to establish a definitive diagnosis and potentially treat the underlying cause was recommended despite the high surgical risk involved and subsequently revealed a foreign body type granuloma, and excluded aspergillosis. Tuberculosis and other granulomatous disease processes were excluded. CONCLUSION: This case illustrates the importance of pathological diagnosis to guide therapy and reminds us that the occasional patient will encounter multiple, rare and unrelated diseases during their lifetime. A high index of suspicion is necessary in patients who have undergone surgical aneurysm repair involving muslin as it may be subject to secondary infection and or granuloma formation many years later.

Assessment of the Subarachnoid Hemorrhage International Trialists (SAHIT) Models for Dichotomized Long-Term Functional Outcome Prediction After Aneurysmal Subarachnoid Hemorrhage in a United Kingdom Multicenter Cohort Study.

BACKGROUND: Long-term outcome after subarachnoid hemorrhage, beyond the first few months, is difficult to predict, but has critical relevance to patients, their families, and carers. OBJECTIVE: To assess the performance of the Subarachnoid Hemorrhage International Trialists (SAHIT) prediction models, which were initially designed to predict short-term (90 d) outcome, as predictors of long-term (2 yr) functional outcome after aneurysmal subarachnoid hemorrhage (aSAH). METHODS: We included 1545 patients with angiographically-proven aSAH from the Genetic and Observational Subarachnoid Haemorrhage (GOSH) study recruited at 22 hospitals between 2011 and 2014. We collected data on age, WNFS grade on admission, history of hypertension, Fisher grade, aneurysm size and location, as well as treatment modality. Functional outcome was measured by the Glasgow Outcome Scale (GOS) with GOS 1 to 3 corresponding to unfavorable and 4 to 5 to favorable functional outcome, according to the SAHIT models. The SAHIT models were assessed for long-term outcome prediction by estimating measures of calibration (calibration slope) and discrimination (area under the receiver-operating characteristic curve [AUC]) in relation to poor clinical outcome. RESULTS: Follow-up was standardized to 2 yr using imputation methods. All 3 SAHIT models demonstrated acceptable predictive performance for long-term functional outcome. The estimated AUC was 0.71 (95% CI: 0.65-0.76), 0.73 (95% CI: 0.68-0.77), and 0.74 (95% CI: 0.69-0.79) for the core, neuroimaging, and full models, respectively; the calibration slopes were 0.86, 0.84, and 0.89, indicating good calibration. CONCLUSION: The SAHIT prediction models, incorporating simple factors available on hospital admission, show good predictive performance for long-term functional outcome after aSAH.

Dietary Patterns in New Zealand Women: Evaluating Differences in Body Composition and Metabolic Biomarkers.

The combinations of food consumed together (dietary patterns) may have a greater influence on health than nutrients or food groups consumed independently. This study investigated the relationship between dietary patterns, body composition and metabolic biomarkers of premenopausal New Zealand women from three ethnic groups. In total, 408 New Zealand European, Maori and Pacific women aged 16-45 years participated in the Women's EXPLORE (EXamining Predictors Linking Obesity Related Elements) study. Participants completed a 220-item food frequency questionnaire. Several body composition parameters and metabolic biomarkers were measured. Dietary patterns were extracted by principal component analysis and dietary pattern scores were categorised into tertiles to assess links with other measured parameters. Women with higher scores for the 'refined and processed' pattern were younger, had higher body mass index, total body fat, plasma leptin and plasma insulin (p < 0.001), and lower plasma ghrelin levels (p < 0.05) than women with lower scores. In addition, more Maori (51%) and Pacific (68%) women followed the 'refined and processed' pattern, while more New Zealand European women (40%) followed the 'sweet and savoury snacking' pattern. These data show that dietary pattern analysis is a useful tool to assess links between diet and metabolic health. It further reveals interesting ethnic group-specific differences in dietary pattern use.

Results of Surgery for Low-Grade Brain Arteriovenous Malformation Resection by Early Career Neurosurgeons: An Observational Study.

BACKGROUND: For sustainability of arteriovenous malformation (AVM) surgery, results from early career cerebrovascular neurosurgeons (ECCNs) must be acceptably safe. OBJECTIVE: To determine whether ECCNs performance of Spetzler-Ponce Class A AVM (SPC A) resection can be acceptably safe. METHODS: ECCNs completing a cerebrovascular fellowship (2004-2015) with the last author were included. Inclusion of the ECCN cases occurred if they: had a prospective database of all AVM cases since commencing independent practice; were the primary surgeon on SPC A; and had made the significant management decisions. All SPC A surgical cases from the beginning of the ECCN's independent surgical practice to a maximum of 8 yr were included. An adverse outcome was considered a complication of surgery leading to a new permanent neurological deficit with a last modified Rankin Scale score >1. A cumulative summation (Cusum) plot examined the performance of each surgery. The highest acceptable level of adverse outcomes for the Cusum was 3.3%, derived from the upper 95% confidence interval of the last author's reported series. RESULTS: Six ECCNs contributed 110 cases for analysis. The median number of SPC A cases operated by each ECCN was 16.5 (range 4-40). Preoperative embolization was performed in 5 (4.5%). The incidence of adverse outcomes was 1.8% (95% confidence interval: <0.01%-6.8%). At no point during the accumulated series did the combined cohort become unacceptable by the Cusum plot. CONCLUSION: ECCNs with appropriate training appointed to large-volume cerebrovascular centers can achieve results for surgery for SPC A that are not appreciably worse than those published from high-volume neurosurgeons.

Severe adverse radiation effects complicating radiosurgical treatment of brain arteriovenous malformations and the potential benefit of early surgical treatment.

Treatment of brain arteriovenous malformations (AVM) with stereotactic radiosurgery is rarely complicated by severe adverse radiation effects (ARE). The treatment of these sequelae is varied and often ineffectual. We present three cases of brain AVMs treated with SRS, all complicated by severe AREs. All three cases failed to respond to what is currently considered the standard treatment - corticosteroids - and indeed one patient died as a result of the side effects of their extended use. Two cases were successfully treated with surgical excision of the necrotic lesion resulting in immediate clinical improvement. Having considered the experience described in this paper and reviewed the published literature to date we suggest that surgical treatment of AREs should be considered early in the management of this condition should steroid therapy not result in early improvement.

Association of functional MMP-2 gene variant with intracranial aneurysms: case-control genetic association study and meta-analysis.

INTRODUCTION: Abnormalities in Matrix Metalloproteinase (MMP) genes, which are important in extracellular matrix (ECM) maintenance and therefore arterial wall integrity are a plausible underlying mechanism of intracranial aneurysm (IA) formation, growth and subsequent rupture. We investigated whether the rs243865 C > T SNP (single nucleotide polymorphism) within the MMP-2 gene (which influences gene transcription) is associated with IA compared to matched controls. MATERIALS AND METHODS: We conducted a case-control genetic association study, adjusted for known IA risk factors (smoking and hypertension), in a UK Caucasian population of 1409 patients with intracranial aneurysms (IA), and 1290 matched controls, to determine the association of the rs243865 C > T functional MMP-2 gene SNP with IA (overall, and classified as ruptured and unruptured). We also undertook a meta-analysis of two previous studies examining this SNP. RESULTS: The rs243865 T allele was associated with IA presence in univariate (OR 1.18 [95% CI 1.04-1.33], p = .01) and in multi-variable analyses adjusted for smoking and hypertension status (OR 1.16 [95% CI 1.01-1.35], p = .042). Subgroup analysis demonstrated an association of the rs243865 SNP with ruptured IA (OR 1.18 [95% CI 1.03-1.34] p = .017), but, not unruptured IA (OR 1.17 [95% CI 0.97-1.42], p = .11). CONCLUSIONS: Our study demonstrated an association between the functional MMP-2 rs243865 variant and IAs. Our findings suggest a genetic role for altered extracellular matrix integrity in the pathogenesis of IA development and rupture.

Fat Sensation: Fatty Acid Taste and Olfaction Sensitivity and the Link with Disinhibited Eating Behaviour.

Perception of fat taste, aroma, and texture are proposed to influence food preferences, thus shaping dietary intake and eating behaviour and consequently long-term health. In this study, we investigated associations between fatty acid taste, olfaction, mouthfeel of fat, dietary intake, eating behaviour, and body mass index (BMI). Fifty women attended three sessions to assess oleic acid taste and olfaction thresholds, the olfactory threshold for n-butanol and subjective mouthfeel ratings of custard samples. Dietary intake and eating behaviour were evaluated using a Food Frequency and Three-Factor Eating Questionnaire, respectively. Binomial regression analysis was used to model fat taste and olfaction data. Taste and olfactory detection for oleic acid were positively correlated (r = 0.325; p < 0.02). Oleic acid taste hypersensitive women had significantly increased n-butanol olfactory sensitivity (p < 0.03). The eating behaviour disinhibition and BMI were higher in women who were hyposensitive to oleic acid taste (p < 0.05). Dietary intake of nuts, nut spreads, and seeds were significantly correlated with high olfactory sensitivity to oleic acid (p < 0.01). These findings demonstrate a clear link between fatty acid taste sensitivity and olfaction and suggest that fat taste perception is associated with specific characteristics of eating behaviour and body composition.

Outcome study of the pipeline embolization device for treatment of intracranial aneurysms at a single UK institution.

BACKGROUND: The introduction of flow-diverting stents in the last decade provides an alternative endovascular treatment choice in selected intracranial aneurysms. This retrospective analysis of a UK centre's experience provides insight into clinical and radiographic outcomes. METHODS: Electronic patient records, diagnostic and procedural images and written procedural records for patients treated with the PED between August 2009 and April 2014 were reviewed. Follow-up TOF MRA was performed after treatment. Clinical and radiographic outcomes were analyzed and compared with other PED studies. RESULTS: Twenty-nine patients with 30 attempted PED treatments were reviewed representing 3.5% of the treated aneurysm patient cohort. 63.6% (21/33) of the aneurysms were wide-necked (>4 mm), 60.6% (20/33) were large or giant (≥10 mm). The mean aneurysm sac diameter was 12.0 mm; the mean neck width was 4.5 mm. Mortality and morbidity rates were 3.3% and 10.0%, respectively. The total adequate occlusion rate was 78.1% (25/32) at 18 months. The neck width of aneurysms with residual sac filling and complete occlusion differed significantly (p = 0.04). CONCLUSIONS: Highly selected aneurysms treated with a PED in a UK centre have similar occlusion and complication rates when compared to non-UK studies. Again, it appeared that delayed aneurysm rupture remained a risk for PED treatment in large or giant aneurysms. Follow-up with TOF MRA gave similar occlusion results compared to those obtained with DSA in other studies. The influence of neck size on occlusion rate should be examined in future PED studies.

Is Sweet Taste Perception Associated with Sweet Food Liking and Intake?

A range of psychophysical taste measurements are used to characterize an individual's sweet taste perception and to assess links between taste perception and dietary intake. The aims of this study were to investigate the relationship between four different psychophysical measurements of sweet taste perception, and to explore which measures of sweet taste perception relate to sweet food intake. Forty-four women aged 20-40 years were recruited for the study. Four measures of sweet taste perception (detection and recognition thresholds, and sweet taste intensity and hedonic liking of suprathreshold concentrations) were assessed using glucose as the tastant. Dietary measurements included a four-day weighed food record, a sweet food-food frequency questionnaire and a sweet beverage liking questionnaire. Glucose detection and recognition thresholds showed no correlation with suprathreshold taste measurements or any dietary intake measurement. Importantly, sweet taste intensity correlated negatively with total energy and carbohydrate (starch, total sugar, fructose, glucose) intakes, frequency of sweet food intake and sweet beverage liking. Furthermore, sweet hedonic liking correlated positively with total energy and carbohydrate (total sugar, fructose, glucose) intakes. The present study shows a clear link between sweet taste intensity and hedonic liking with sweet food liking, and total energy, carbohydrate and sugar intake.

Aneurysms in neurofibromatosis type 2: Evidence for vasculopathy?

There have been anecdotal reports of vasculopathy associated with Neurofibromatosis Type 2 (NF2). Given the increasing use of bevacizumab, a vascular endothelial growth factor inhibitor which results in an increased risk of bleeding, it is important to ascertain if there is a predisposition to vascular abnormalities in NF2. In our unit NF2 patients undergo annual MRI brain and internal auditory meatus imaging. We noted incidental intracranial aneurysms in some patients and sought to determine the prevalence of intracranial aneurysms in our cohort of NF2 patients. We conducted a retrospective audit of the MRI images of 104 NF2 patients from 2014 to 2016. Axial T2 brain MRI images were assessed for vascular abnormalities by two neuroradiologists blinded to patient's clinical details. Intracranial aneurysms were detected in four patients and an aneurysm clip related to previous surgery was noted in one additional patient. Using standard MRI imaging sequences alone we provide evidence of intracranial aneurysms in 4.4% of our cohort. This compares with an estimated overall prevalence of 3% in the general population. We discuss these findings as well as other evidence for a vasculopathy associated with NF2.

Electrophysiological/sonographic mapping of the superficial peroneal nerve to facilitate biopsy under local anaesthesia.

The anatomical surface markings for the superficial peroneal nerve have been described and it may be preferred for biopsy in cases of suspected vasculitis as biopsy of the peroneus brevis muscle increases diagnostic yield. The procedure is however unfamiliar to many surgeons and the anatomical variability of the subcutaneous part underestimated. Where the nerve has some preserved sensory nerve action potential it may be mapped pre-operatively, greatly facilitating minimally traumatic biopsy with potential logistical and wound healing advantages. We review the literature relating to the anatomical course of the nerve and present a case illustrating the advantages of pre-operative mapping, given its location in the anterior compartment of the leg 26% of the time.

Simultaneous monitoring of potassium, glucose and lactate during spreading depolarization in the injured human brain - Proof of principle of a novel real-time neurochemical analysis system, continuous online microdialysis.

Spreading depolarizations occur spontaneously and frequently in injured human brain. They propagate slowly through injured tissue often cycling around a local area of damage. Tissue recovery after an spreading depolarization requires greatly augmented energy utilisation to normalise ionic gradients from a virtually complete loss of membrane potential. In the injured brain, this is difficult because local blood flow is often low and unreactive. In this study, we use a new variant of microdialysis, continuous on-line microdialysis, to observe the effects of spreading depolarizations on brain metabolism. The neurochemical changes are dynamic and take place on the timescale of the passage of an spreading depolarization past the microdialysis probe. Dialysate potassium levels provide an ionic correlate of cellular depolarization and show a clear transient increase. Dialysate glucose levels reflect a balance between local tissue glucose supply and utilisation. These show a clear transient decrease of variable magnitude and duration. Dialysate lactate levels indicate non-oxidative metabolism of glucose and show a transient increase. Preliminary data suggest that the transient changes recover more slowly after the passage of a sequence of multiple spreading depolarizations giving rise to a decrease in basal dialysate glucose and an increase in basal dialysate potassium and lactate levels.

Spontaneous epidural spinal haematoma in children caused by vascular malformations.

PURPOSE: The occurrence of spinal epidural haematoma of 'spontaneous' origin in adults is a well-documented entity, though it is rare in children. In the literature to date, there are few cases of this kind of spontaneous haematoma proven to be due to an underlying vascular abnormality. METHOD: Retrospective review of two cases of children under 15 years of age with spontaneous epidural spinal haematoma. RESULTS: Underlying arteriovenous malformations were identified in both cases. Intra-operative photographs and histological sections of these anomalies are presented. CONCLUSION: These are the first two such cases described with clinico-pathological correlation.

Detection of spreading depolarization with intraparenchymal electrodes in the injured human brain.

BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can be detected using intra-cortical electrodes, opening the way for electrode insertion via burr hole. METHODS: Animal work was carried out on adult Sprague-Dawley rats in a laboratory setting to investigate the feasibility of recording depolarization events. Subsequently, 8 human patients requiring craniotomy for traumatic brain injury or aneurysmal subarachnoid hemorrhage were monitored for depolarization events in an intensive care setting with concurrent strip (subdural) and depth (intra-parenchymal) electrode recordings. RESULTS: (1) Depolarization events can be reliably detected from intra-cortically placed electrodes. (2) A reproducible slow potential change (SPC) waveform morphology was identified from intra-cortical electrodes on the depth array. (3) The depression of cortical activity known to follow depolarization events was identified consistently from both intra-cortical and sub-cortical electrodes on the depth array. CONCLUSIONS: Intra-parenchymally sited electrodes can be used to consistently identify depolarization events in humans. This technique greatly extends the capability of monitoring for spreading depolarization events in injured patients, as electrodes can be sited without the need for craniotomy. The method provides a new investigative tool for the evaluation of the contribution of these events to secondary brain injury in human patients.

Intraoperative indocyanine green video-angiography as an aid to the microsurgical treatment of spinal vascular malformations.

AIMS AND OBJECTIVES. Intra-operative Indocyanine Green (ICG) video-angiography (ICG-VA) has become an established aid to cerebrovascular surgery. We describe our experience using this technique to define angio-architecture intraoperatively in a range of spinal vascular malformations. METHODS. A retrospective review of notes and imaging was carried out from a prospectively maintained database. Our series comprises 27 patients who underwent surgical treatment between September 2007 and August 2012. We carried out a retrospective review of data from a prospectively maintained database. RESULTS. For slow-flow Type 1 fistulae the ICG videoangiogram demonstrated conclusively that the arteriovenous shunt was obliterated. This is a consideration on the rare occasions where a second fistula is present, an example of which is included in this series. ICG-VA also helps to demonstrate normal vascular anatomy and distinguish these vessels from pathology. For Type II lesions it allowed orientation to the vascular anatomy as demonstrated by the pre-operative angiogram. In one of two cases in this series it ensured to the complete extirpation of a large arteriovenous malformation (AVM). However a second Type II case demonstrated its limitations, as a diffuse intramedullary component could not be identified. Two cases were explored where digital subtraction spinal angiography was not possible and incomplete understanding of the angio-architectures of the lesions were available from Time Resolved dynamic magnetic resonance angiography and/or multi-detector CT angiography. ICG-VA provided invaluable information on alterations in arterio-venous flow that allowed diagnosis and obliteration of the arteriovenous shunts in each case. DISCUSSION. ICG video-angiography is a time-efficient and safe alternative to intra-operative spinal angiography. It provided useful information on haemodynamic changes intraoperatively and completeness of treatment. We discuss its limitations and role in the management of these lesions.

Estimating differential reproductive success from nests of related individuals, with application to a study of the mottled sculpin, Cottus bairdi.

Understanding how variation in reproductive success is related to demography is a critical component in understanding the life history of an organism. Parentage analysis using molecular markers can be used to estimate the reproductive success of different groups of individuals in natural populations. Previous models have been developed for cases where offspring are random samples from the population but these models do not account for the presence of full- and half-sibs commonly found in large clutches of many organisms. Here we develop a model for comparing reproductive success among different groups of individuals that explicitly incorporates within-nest relatedness. Inference for the parameters of the model is done in a Bayesian framework, where we sample from the joint posterior of parental assignments and fertility parameters. We use computer simulations to determine how well our model recovers known parameters and investigate how various data collection scenarios (varying the number of nests or the number of offspring) affect the estimates. We then apply our model to compare reproductive success among different age groups of mottled sculpin, Cottus bairdi, from a natural population. We demonstrate that older adults are more likely to contribute to a nest and that females in the older age groups contribute more eggs to a nest than younger individuals.