RARE-01. MANAGEMENT AND OUTCOMES OF PAEDIATRIC CRANIOPHARYNGIOMA: A 15-YEAR EXPERIENCE IN SINGAPORE

BACKGROUND

Craniopharyngiomas are rare embryonic malformations of the sellar region with high survival rates but high morbidity due to long-term sequelae caused by the location of the tumour. We summarise our institution’s experience on the management and outcomes of paediatric craniopharyngiomas in Singapore.

METHODS

This was a retrospective review of all paediatric patients (18 years and below) with histologically diagnosed craniopharyngioma managed by the National University Hospital, Singapore from January 2002 to June 2017. Data on clinical presentation, imaging, treatments, and outcomes were extracted from the electronic medical records using a standardized data collection form. Data analysis was conducted using RStudio (Version 1.2.5033). Institutional ethics approval was obtained for the study.

RESULTS

We identified 12 cases of paediatric craniopharyngiomas. The majority of cases were male (8, 66.7%) and the median age at presentation was 6.0 (IQR 3.8 – 9.5). Initial surgical management was tumour excision (11, 91.7%) or insertion of a reservoir into the cyst cavity (1, 8.3%). All cases had diabetes insipidus, 10 (83.3%) had endocrine dysfunction, and 8 (66.7%) had visual impairment on long term follow up. 7 (58.3%) cases had recurrence, and 3 (25.0%) had demised. Cox-regression showed that females (HR=33.9, p=0.049), and Chinese race (HR=13.3, p=0.034) were at higher risk for recurrence, but age at diagnosis and residual tumor on post-operative MRI was not significant.

CONCLUSION

The management of craniopharyngioma is complex as it is complicated by high recurrence rates and significant long-term morbidity. Further research on treatment strategies focusing on maintaining quality of life is important.

Revascularisation surgery for paediatric moyamoya disease: The Singapore experience

Moyamoya disease (MMD) is characterized by the spontaneous occlusion of the distal internal carotid arteries and resultant neo-angiogenesis of fragile collateral blood vessels. Direct and indirect revascularization surgeries have shown to effectively reduce stroke risks in paediatric MMD, whereby the latter is a more utilised technique in children. This study was undertaken to determine the outcomes of revascularization in Singapore's multi-ethnic, Southeast Asian paediatric population. This is an ethics-approved study conducted in Singapore's 2 tertiary children hospital units: KK Women's and Children's Hospital and National University Hospital. Sixteen patients with a diagnosis of ischaemic-type MMD are recruited between 01 January 2002 to 31 January 2019; and a total of 24 surgeries are undertaken (24 cerebral hemispheres). There are 2 cases of stroke within 30 days post-surgery. However, no stroke recurrence is observed beyond 30 days after surgery in all patients. Four patients reported recurrent transient ischaemic attack symptoms in the follow-up period ranging from 3 months to 12 years. Data analyses show a statistically significant improvement in modified Rankin's Scale (mMRS) in post-operative patients from baseline to discharge, and at 3 months after surgery. Our study also observes that predictors of recurrent ischaemic events include higher pre-operative MRS, Suzuki stage and perioperative infarction. To the authors' knowledge, this is the first study to date reporting the outcomes of revascularisation in a paediatric Southeast Asian cohort.

COVID-19 response measures - a Singapore Neurosurgical Academic Medical Centre experience segregated team model to maintain tertiary level neurosurgical care during the COVID-19 outbreak

Aim: This article aims to inform and share the experience of a Singaporean tertiary level neurosurgical unit in an academic medical centre during the COVID-19 outbreak. Method: This is a descriptive study of our segregation team model which is designed with the aim of optimizing manpower and ensuring the safety and welfare of the neurosurgical unit, while maintaining and prioritizing excellent patient care. Result: We describe our method of team segregation, rostering, and outline some principles that we adhere to in its design. We also summarise the restructuring of our inpatient and outpatient service, including the operating theatre and protocols for specific procedures, intensive care and general wards, as well as clinic services and multidisciplinary meetings. Conclusion: We end with a commentary on residency training and anticipated challenges. Given the likely protracted course of the pandemic, it is key to account for sustainability of such measures and the conservation of resource via the reduction of pateint volume, upkeep of staff emotional and physical health and harnessing technologies such as telemedicine.

Coexisting Moyamoya Syndrome and Type 1 Diabetes Mellitus: A Case Report and Review of the Literature

Moyamoya disease (MMD) is an incompletely understood malady that affects many age groups, primarily in a bimodal age distribution. We present a patient with the association of type 1 diabetes mellitus (type 1 DM) and MMD followed by a review of the existing literature. We found five papers that describe this association, in the form of one case report, one case series, and three retrospective reviews. Despite a poor understanding of the underlying pathophysiology, a clear association between autoimmune conditions and MMD appears to exist. Clinicians who manage such patients ought to be vigilant and have a high index of suspicion when young patients with type 1 DM present with new onset of neurological symptoms.

Freehand Insertion of External Ventricular Drainage Catheter: Evaluation of Accuracy in a Single Center

Introduction

External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks, is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion.

Patients and Methods

Preoperative and postoperative computed tomography scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evans ratio, midline shift, position of burr hole, length of the catheter, and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter.

Results

Seventy-seven EVD placements in seventy patients were evaluated. The mean age of the patients was 57.5 years. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum, and interhemispheric fissure. Nearly 5.2% were in extraventricular locations. Almost 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the two groups, no significant difference was observed in Evans ratio, midline shift, surgeon's experience, distance of burr hole from midline, and coronal suture.

Conclusion

Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.

Factors Predicting Outcomes in Surgically Treated Pediatric Traumatic Brain Injury

Introduction

Traumatic brain injury (TBI) is a common presentation to the pediatric emergency department. Understanding factors that predict outcomes will be useful in clinical decision-making and prognostication. The objective of this study was to identify important clinical parameters predictive of outcomes in pediatric TBI patients who underwent surgery.

Materials and Methods

This retrospective study included 43 pediatric TBI patients who underwent surgery from January 2011 to January 2017. Clinical parameters, including presenting signs and symptoms, mechanism of injury, intracranial pressure (ICP), need for inotropes, and computed tomography findings were collected. Outcomes were assessed using the Glasgow outcome score (GOS) based on the latest follow-up. Outcomes were divided into favorable (GOS 4-5) and unfavorable (GOS 1-3).

Results

Surgery was performed in 43 patients. The mean age was 9.6 ± 4.9. The mean follow-up period was 31 weeks. Thirty (70%) patients had favorable outcome and 13 (30%) had unfavorable outcome. On univariate analysis, mechanism of injury, vomiting, Glasgow coma scale score, pupil size and reactivity, hypotension, inotropic use, need for blood transfusion, and raised ICP (all P < 0.005) were significantly associated with outcomes. On step-wise logistic regression, only raised ICP (odds ratio [OR] = 35.6, P = 0.008) and hypotension (OR = 26.1, P = 0.01) were found to be statistically significant.

Conclusion

The present study suggests that the majority of pediatric TBI patients who required neurosurgical intervention have favorable outcomes. Closer attention should be paid to raised ICP and hypotension as they were strong predictors of unfavorable outcomes. These findings also help manage expectations of patients' family and clinicians.

Outcomes of Subdural Versus Subperiosteal Drain After Burr-Hole Evacuation of Chronic Subdural Hematoma: A Multicenter Cohort Study

BACKGROUND

Although the use of a postoperative drain after burr-hole evacuation of chronic subdural hematoma (CSDH) is known to improve surgical outcomes, the superiority of subdural over subperiosteal drains has not been firmly established. Evidence comparing these 2 drain types is largely restricted to single-center series with limited numbers. Using a multicenter cohort study, we aimed to show noninferiority of subperiosteal drains vis-à-vis subdural drains after burr-hole evacuation of CSDH.

METHODS

We performed a retrospective analysis of all consecutive patients with CSDH aged 21 years and older who had undergone burr-hole craniostomy across 3 tertiary hospitals from 2010 to 2017. Primary outcome measures included CSDH recurrence and modified Rankin Scale (mRS) score at 6 months. Outcomes of patients in the subdural and subperiosteal drain groups were analyzed and confounders were adjusted for using multivariate logistic regression.

RESULTS

Of the 570 cases analyzed, 329 (57.7%) received a subdural drain and 241 (42.3%) received a subperiosteal drain. There was no significant difference between the 2 drain groups in CSDH recurrence (13.1% in the subdural group vs. 11.2% in the subperiosteal group; P = 0.502) or 6-month mRS score (27.2% with mRS 4-6 in the subdural group vs. 20.4% in the subperiosteal group; P = 0.188). Independent predictors of CSDH recurrence identified on multivariate analysis included premorbid mRS score 0-3 (P = 0.021), separated CSDH type on preoperative computed tomography scan (P = 0.002), and postoperative pneumocephalus of ≥15 mm (P = 0.005).

CONCLUSIONS

Outcomes of subdural and subperiosteal drains after burr-hole craniostomy for CSDH are largely equivalent based on our findings.

Reversal of the reversed 'Robin Hood syndrome' after superficial temporal-Middle cerebral artery bypass for severe intracranial stenosis

Background: Intracranial arterial stenosis is a common cause of ischemic stroke. Recent attempts with intracranial stenting and superficial temporal-middle cerebral artery (STA-MCA) bypass failed to show benefit. Perhaps, better strategies are needed for selecting suitable patients. Acetazolamide-challenged single photon emission computed tomography (SPECT) can demonstrate reversed Robin Hood syndrome (RRHS) due to intracranial steal phenomenon and identify high-risk patients.Methods: We describe the clinical and SPECT findings of RRHS.Results: In our patient with severe and symptomatic severe stenosis of the right MCA, STA-MCA bypass resulted in complete resolution of RRHS.Conclusion: STA-MCA bypass surgery should be considered a possible option in patients with severe stenosis of intracranial internal carotid artery or MCA in carefully selected patients.

Freehand Insertion of External Ventricular Drainage Catheter–Evaluation of Accuracy in a Single Centre

INTRODUCTION

External ventricular drain (EVD) placement is the gold standard for managing acute hydrocephalus. Freehand EVD, using surface anatomical landmarks is performed for ventricular cannulation due to its simplicity and efficiency. This study evaluates accuracy and reason(s) for misplacements as few studies have analyzed the accuracy of freehand EVD insertion.

METHODS

Preoperative and postoperative computed tomography (CT) scans of patients who underwent EVD insertion in 2014 were retrospectively reviewed. Diagnosis, Evan's ratio, midline shift, position of burr hole, length of the catheter and procedural complications were tabulated. The procedures were classified as satisfactory (catheter tip in the frontal horn ipsilateral lateral ventricle) and unsatisfactory. Unsatisfactory cases were further analyzed in relation to position of burr hole from midline and length of the catheter.

RESULTS

A total of 77 EVD placements in 70 patients were evaluated. Mean age of the patients was 57.5 yr. About 83.1% were satisfactory placements and 11.7% were unsatisfactory in the contralateral ventricle, corpus callosum and interhemispheric fissure. About 5.2% were in extra ventricular locations. About 2.6% EVD placements were complicated by hemorrhage and 1 catheter was reinserted. Suboptimal placements were significantly associated with longer intracranial catheter length. The mean length was 66.54 ± 10.1 mm in unsatisfactory placements compared to 58.32 ± 4.85 mm in satisfactory placements. Between the 2 groups, no significant difference was observed in Evan's ratio, midline shift, surgeon's experience, distance of burr hole from midline and coronal suture.

CONCLUSION

Freehand EVD insertion is safe and accurate. In small number of cases, unsatisfactory placement is related to longer catheter length.

Health-related quality of life loss associated with first-time stroke

OBJECTIVES

This study aimed to quantify health-related quality of life (HRQoL) loss associated with first episode of stroke by comparing patient-reported HRQoL before and after stroke onset. The impact of stroke in local population was also evaluated by comparing the pre- and post-stroke HRQoL with that of the general population.

METHODS

The HRQoL of stroke survivors was assessed with the EQ-5D-3L index score at recruitment, for recalled pre-stroke HRQoL, and at 3 and 12 month post-stroke. Change in HRQoL from pre-stroke to 3 and 12 month was self-reported by 285 and 238 patients, respectively. Mean EQ index score at each time point (baseline: 464 patients; 3 month post-stroke: 306 patients; 12 month post-stroke: 258 patients) was compared with published population norms for EQ-5D-3L.

RESULTS

There was a significant decrease in HRQoL at 3 (0.25) and 12 month (0.09) post-stroke when compared to the retrospectively recalled patients' mean pre-stroke HRQoL level (0.87). The reduction at 3 month was associated with the reduction in all EQ-5D-3L health dimensions; reductions remaining at 12 month were limited to dimensions of mobility, self-care, usual activities, and anxiety/depression. Stroke patients had a lower mean EQ index than the general population by 0.07 points pre-stroke (0.87 vs. 0.94), 0.33 points at 3 month (0.61 vs. 0.94) and 0.18 points at 12 month (0.76 vs. 0.94) post-stroke.

CONCLUSIONS

Stroke has a substantial impact on HRQoL in Singapore, especially in the first three months post-stroke. Compared to the general population, stroke survivors have lower HRQoL even before stroke onset. This pre-stroke deficit in HRQoL should be taken into account when quantifying health burden of stroke or setting goals for stroke rehabilitation.

Can acute clinical outcomes predict health-related quality of life after stroke: a one-year prospective study of stroke survivors

BACKGROUND

Health-related quality of life (HRQoL) is a key metric to understand the impact of stroke from patients' perspective. Yet HRQoL is not readily measured in clinical practice. This study aims to investigate the extent to which clinical outcomes during admission predict HRQoL at 3 months and 1 year post-stroke.

METHODS

Stroke patients admitted to five tertiary hospitals in Singapore were assessed with Shah-modified Barthel Index (Shah-mBI), National Institute of Health Stroke Scale (NIHSS), Modified Rankin Scale (mRS), Mini-Mental State Examination (MMSE), and Frontal Assessment Battery (FAB) before discharge, and the EQ-5D questionnaire at 3 months and 12 months post-stroke. Association of clinical measures with the EQ index at both time points was examined using multiple linear regression models. Forward stepwise selection was applied and consistently significant clinical measures were analyzed for their association with individual dimensions of EQ-5D in multiple logistic regressions.

RESULTS

All five clinical measures at baseline were significant predictors of the EQ index at 3 months and 12 months, except that MMSE was not significantly associated with the EQ index at 12 months. NIHSS (3-month standardized β = - 0.111; 12-month standardized β = - 0.109) and mRS (3-month standardized β = - 0.122; 12-month standardized β = - 0.080) were shown to have a larger effect size than other measures. The contribution of NIHSS and mRS as significant predictors of HRQoL was mostly explained by their association with the mobility, self-care, and usual activities dimensions of EQ-5D.

CONCLUSIONS

HRQoL at 3 months and 12 months post-stroke can be predicted by clinical outcomes in the acute phase. NIHSS and mRS are better predictors than BI, MMSE, and FAB.

Challenges in the Management of a Ruptured Bihemispheric Posterior Inferior Cerebellar Artery Aneurysm

BACKGROUND

Bihemispheric posterior inferior cerebellar artery (PICA) is a rare anatomic variant wherein a single PICA supplies both cerebellar hemispheres. Inasmuch as it is the only PICA, treatment of aneurysms arising from this anatomic variant is more complex. We present a case of a ruptured bihemispheric PICA aneurysm and the challenges encountered in its management.

CASE DESCRIPTION

A 54-year-old man presented with giddiness and nausea. Otherwise, he was neurologically intact. Computed tomography of the brain showed a right cerebellar hematoma and intraventricular hemorrhage. Cerebral angiography revealed a dissecting aneurysm in the retromedullary segment of a right bihemispheric PICA with a prominent saccular component. Initially, the patient refused to undergo any invasive treatment. However, when a follow-up angiogram showed an increase in the size of the aneurysm sac, he consented to treatment. Although parent vessel occlusion (PVO) was the clinical recommendation, in view of the patient's apprehensions, only the saccular component of the aneurysm was coil embolized without sacrifice of the parent vessel. Fifteen days after the coiling, there was a rebleed from this dissecting aneurysm, which was treated with PVO followed by suboccipital craniectomy. The patient made a reasonable recovery, and his modified Rankin score was 1 at his 6-month follow-up visit.

CONCLUSIONS

In dissecting aneurysms of a bihemispheric PICA, isolated endosaccular occlusion provides uncertain protection from a rebleed, whereas a more reliable treatment with PVO carries an unpredictable risk of ischemic complications. The risks of a PVO may be rationalized as a life-saving measure; however, the subsequent threshold for posterior fossa decompression should be low.

Abstract TP316: Early Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction in Asian Patients

Background and purpose: Decompression craniectomy in acute malignant middle cerebral artery (MCA) ischemic stroke (IS) reduces mortality. However, its role in reducing disability in this group of patients is often questioned in the stroke community since previous studies have employed variable time intervals for surgical decompression as well as criteria for defining severe disability. We evaluated our Asian cohort of acute IS patients for determining the factors associated with favorable functional outcome.

Methods: Data for all acute IS patients hospitalized to our tertiary center were entered into a prospectively maintained registry. In this retrospective analysis, data for all malignant MCA IS patients who underwent decompressive hemicraniectomy were extracted. Various demographic, clinical and neuroimaging factors were analyzed for identifying independent predictors of favorable functional outcome at 6 months, which was defined as modified Rankin Scale of 0-3.

Results: From January 2005 to December 2014, a total of 75 patients with anterior circulation IS underwent decompressive hemicraniectomy. Median age was 55 years (IQR 44-64) with male preponderance (66%) and median NIH Stroke Scale (NIHSS) score 21 points (IQR 18-24). Considerable proportion of them (60%) received intravenous thrombolysis with tissue plasminogen activator (IV-tPA). Majority (70%) of patients suffered from acute right MCA IS and median time from symptom-onset to surgery was 31 hours (range18-51). Decompressive surgery was performed within 48 hours of symptom-onset in 50 (67%) of the patients. Favorable functional outcome was achieved by 25 (33.3%) patients at 6 months. Right sided stroke (OR 5.333; 95% CI 1.359- 20.927, p=0.016 ) and early decompression surgery (performed within 48 hours from symptom-onset (OR 3.636; 95% CI 1.032- 12.809, p=0.045 ) were independent predictors of favorable functional outcome at 6 months.

Conclusion: Early decompression craniectomy, especially in right MCA ischemic stroke is associated with better favorable functional outcome at 6 months.

Improvement in cerebral hemodynamic parameters and outcomes after superficial temporal artery-middle cerebral artery bypass in patients with severe stenoocclusive disease of the intracranial internal carotid or middle cerebral arteries

OBJECT

Both the older and the recent extracranial-intracranial (EC-IC) bypass trials for symptomatic carotid occlusion failed to demonstrate a reduction in stroke recurrence. However, the role of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in patients with symptomatic intracranial stenoocclusive disease has been rarely evaluated. The authors evaluated serial changes in various cerebral hemodynamic parameters in patients with severe stenoocclusive disease of the intracranial internal carotid artery (ICA) or middle cerebral artery (MCA) and impaired cerebral vasodilatory reserve (CVR), treated by STA-MCA bypass surgery or medical treatment.

METHODS

Patients with severe stenoocclusive disease of the intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using the breath-holding index (BHI). Patients with impaired BHI (< 0.69) were further evaluated with acetazolamide-challenge technitium-99m hexamethylpropyleneamine oxime ((99m)Tc HMPAO) SPECT. STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. All patients underwent TCD and SPECT at 4 ± 1 months and were followed up for cerebral ischemic events.

RESULTS

A total of 112 patients were included. This total included 73 men, and the mean age of the entire study population was 56 years (range 23-78 years). (99m)Tc HMPAO SPECT demonstrated impaired CVR in 77 patients (69%). Of these 77 patients, 46 underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenge (99m)Tc HMPAO SPECT repeated at 4 ± 1 months showed significant improvement in the STA-MCA bypass group. During a mean follow-up of 34 months (range 18-39 months), only 6 (13%) of 46 patients in the bypass group developed cerebral ischemic events, as compared with 14 (45%) of 31 patients receiving medical therapy (absolute risk reduction 32%, p = 0.008).

CONCLUSIONS

STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial stenoocclusive disease of the intracranial ICA or MCA results in significant improvement in hemodynamic parameters and reduction in stroke recurrence.

Cerebellar strokes: a clinical outcome review of 79 cases

INTRODUCTION

Cerebellar infarcts and haemorrhages are relatively uncommon, accounting for less than 10% of all strokes. The objective of the present study was to quantify and compare the outcomes of patients with cerebellar infarct and those of patients with cerebellar haemorrhage, as well as to identify the risk factors that predict poor outcome in patients with cerebellar stroke.

METHODS

We retrospectively reviewed the medical records of consecutive patients admitted to National University Hospital, Singapore, between 2004 and 2006, within one week of cerebellar stroke onset. Baseline data included demographics, concomitant comorbidities, and the presence or absence of brainstem compression and hydrocephalus (on computed tomography or magnetic resonance imaging). The Glasgow Outcome Scale and modified Rankin Score were used to assess outcome at discharge and at six months after discharge.

RESULTS

A total of 79 patients with cerebellar stroke were admitted during the study period. Of these 79 patients, 17.7% died and 31.6% had poor outcomes at six months after discharge. Patients with cerebellar haemorrhage were found to be more likely to have poor outcomes as compared to patients with cerebellar infarct, both at discharge (odds ratio [OR] 4.3, 95% confidence interval [CI] 1.3-14.1) and at six months after discharge (OR 5.2, 95% CI 1.6-17.2). When compared to small lesions (< 5 cm(3)), lesions > 20 cm(3) were significantly associated with poorer outcomes and the development of hydrocephalus and brainstem compression.

CONCLUSION

Cerebellar strokes are a significant cause of morbidity and mortality. The outcomes of patients with cerebellar haemorrhage are more likely to be worse than those of patients with cerebellar infarct.

Abstract 74: Improvement in Cerebral Hemodynamic Parameters and Outcome after Superficial Temporal Artery- Middle Cerebral Artery Bypass in Patients with Severe Steno-occlusive Disease of Intracranial Carotid and Middle Cerebral Artery

Background and Objective: Older and the recent extracranial-intracranial (EC/IC) bypass trials for symptomatic carotid occlusion failed to demonstrate reduction in stroke recurrence. However, role of superficial temporal artery-middle cerebral artery (STA-MCA) bypass in patients with symptomatic intracranial steno-occlusive disease has been evaluated scarcely. We evaluated serial changes in various cerebral hemodynamic parameters in patients with severe steno-occlusive disease of intracranial internal carotid (ICA) or middle cerebral artery (MCA) and impaired cerebral vasodilatory reserve (CVR), treated with STA-MCA bypass surgery or medical treatment.

Methods: Patients with severe steno-occlusive disease of intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using breath-holding index (BHI). Patients with impaired BHI (<0.69) were further evaluated with acetazolamide-challenged hexamethylpropyleneamine-oxime single-photon emission computed tomography (HMPAO-SPECT). STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. All patients underwent TCD and SPECT at 4±1 months and followed-up for cerebral ischemic events.

Results: A total of 112patients (73males, mean age 56yrs; range 23-78yrs) were included. HMPAO-SPECT demonstrated impaired CVR in 77 (69%) patients. Of them, 46 underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenged HMPAO-SPECT repeated 4±1months showed significant improvement in STA-MCA bypass group. During follow-up (mean 34months; range 18-39months), only 6/46 (13%) patients in bypass group developed cerebral ischemic events as compared to 14/31 (45%) cases on medical therapy (absolute risk-reduction 32%, p=0.008).

Conclusion: STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial steno-occlusive disease results in significant improvement in hemodynamic parameters and reduction in stroke recurrence.

Effects of polycaprolactone-based scaffolds on the blood-brain barrier and cerebral inflammation

Severe pathoanatomical and mechanical injuries compromise patient recovery and survival following penetrating brain injury (PBI). The realization that the blood-brain barrier (BBB) plays a major role in dictating post-PBI events has led to rising interests in possible therapeutic interventions through the BBB. Recently, the choroid plexus has also been suggested as a potential therapeutic target. The use of biocompatible scaffolds for the delivery of therapeutic agents, but little is known about their interaction with cerebral tissue, which has important clinical implications. Therefore, the authors have sought to investigate the effect of polycaprolactone (PCL) and PCL/tricalcium phosphate (PCL/TCP) scaffolds on the maintenance of BBB phenotype posttraumatic brain injury. Cranial defects of 3 mm depth were created in Sprague Dawley rats, and PCL and PCL/TCP scaffolds were subsequently implanted in predetermined locations for a period of 1 week and 1 month. Higher endothelial barrier antigen (EBA) expressions from PCL-based scaffold groups (p>0.05) were found, suggesting slight advantages over the sham group (no scaffold implantation). PCL/TCP scaffold group also expressed EBA to a higher degree (p>0.05) than PCL scaffolds. Importantly, higher capillary count and area as early as 1 week postimplantation suggested lowered ischemia from the PCL/TCP scaffold group as compared with PCL and sham. Evaluation of interlukin-1β expression suggested that the PCL and PCL/TCP scaffolds did not cause prolonged inflammation. BBB transport selectivity was evaluated by the expression of aquaporin-4 (AQP-4). Attenuated expression of AQP-4 in the PCL/TCP group (p<0.05) suggested that PCL/TCP scaffolds altered BBB selectivity to a lower degree as compared with sham and PCL groups, pointing to potential clinical implications in reducing cerebral edema. Taken together, the responses of PCL-based scaffolds with brain tissue suggested safety, and encourages further preclinical evaluation in PBI management with these scaffolds.

Intracranial pial arteriovenous fistula in infancy: a case report and literature review

Intracranial pial arteriovenous fistulas (AVF) are rare vascular malformation especially in the first 2 years of life. The pathology in this age group is associated with greater morbidity and mortality. We report a rare case of 36-day-old male infant with a pial AVF associated with an arterial aneurysm, who presented with intraventricular hemorrhage and hydrocephalus. In addition, an online review of the literatures on pediatric pial AVF was performed using PubMed on published case reports and articles from 1980 to April 2013.

Abstract W P228: Delayed Decompression Hemicraniectomy in Massive Hemispheric Infarction Reduces Mortality but Does Not Improve Functional Outcome

Background: Massive hemispheric infarctions associated with extensive cerebral edema are associated with grave prognosis. Decompressive hemicraniectomy improves outcomes if performed within 48-hours of stroke-onset. In Asia, surgical decompression is often performed late, often after significant clinic-radiological deterioration occurs. We report our experience with decompressive hemicraniectomy when performed after clinical deterioration, radiologolic herniation or pupil dilatation.

Methods: In this retrospective review, we identified acute anterior circulation ischemic stroke patients who underwent ‘delayed’ decompressive hemicraniectomy at our tertiary institution during 2006-2012. We defined ‘delayed’ surgical intervention as the decompressive hemicraniectomy performed after rapid neurological deterioration (drop of 2 or more points on the Glasgow Coma Scale), evidence of cerebral herniation on clinical and/or neuroimaging criteria. Poor functional outcomes were assessed by modified Rankin score 4-6 points at 90 days.

Results: A total of 54 patients (11males, mean age 56 years; range 26-77 years) were included in this study, 36 (67%) male. Mean NIHSS at the time of hospital admission was 21 points (range 12-29). All patient developed clinical deterioration, pupil dilatation and/or radiological signs of cerebral herniation before decompressive surgery. Median time elapsed between stroke onset and surgery was 50.5 hours (range 11-144). Poor functional outcomes were noted in 40 (74%) with mortality in 16 (30%). Univariate analysis revealed higher age, late time to surgery, pupil dilatation and rapid neurological deterioration before surgery associated with poor outcomes. However logistic regression revealed only delayed hemicraniectomy (OR 1.153 per hour increase; 95% confidence interval 1.036-1.283, p=0.009) as the independent predictor of poor functional outcome.

Conclusions: Although delayed decompressive hemicraniectomy in massive hemispheric ischemic stroke reduces mortality, it results in poor functional outcomes. Our results support early surgical intervention, independent of clinical deterioration or radiological herniation for reducing disabilities and the burden on the families.

Abstract T MP26: Role of 99tc-hmpao Spect in the Assessment of Cerebral Hemodynamic Parameters After Superficial Temporal Artery- Middle Cerebral Artery Bypass in Patients With Severe Steno-Occlusive Disease of Intracranial Carotid and Middle Cerebral Artery

Background and Objective: Although superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery in patients with symptomatic carotid occlusion failed to demonstrate any benefit, its role in symptomatic intracranial steno-occlusive disease has been evaluated scarcely. We evaluated changes in hemodynamic parameters in patients with severe steno-occlusive disease of intracranial internal carotid (ICA) or middle cerebral artery (MCA) who underwent STA-MCA bypass for impaired cerebral vasodilatory reserve (CVR).

Methods: Patients with severe steno-occlusive disease of intracranial ICA or MCA underwent transcranial Doppler (TCD) evaluation and CVR assessment using breath-holding index (BHI). Patients with impaired BHI (<0.69) were further evaluated with acetazolamide-challenged 99Tc-HMPAO-SPECT. STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. TCD and SPECT were repeated in all patients at 4±1 months and they were followed-up for cerebral ischemic events.

Results: Of the 126 patients (80 male, mean age 56yrs; range 23-78yrs) that fulfilled our inclusion criteria, 84 (67%) showed impaired CVR HMPAO-SPECT. Fifty (60%) of them underwent STA-MCA bypass while 34(40%) received best medical treatment. TCD and acetazolamide-challenged HMPAO-SPECT repeated 4±1 months after surgery showed significant improvement in STA-MCA bypass group. TCD BHI improved from a median (IQR) of -0.05 to 1.1 (p<0.001). Compared to 98% patients with impaired CVR on pre-operative SPECT, only 20% showed abnormal results on post-operative imaging (p<0.001). During follow-up (mean 35 months; range 8 to 49months), only 6/50 (12%) patients in bypass group developed cerebral ischemic events as compared to15/34 (44%) cases on medical therapy (absolute risk reduction 32%, p=0.006).

Conclusion: 99Tc-HMPAO SPECT with acetazolamide challenge is a reliable tool for the assessment of cerebral vasodilatory reserve in patients with severe steno-occlusive disease of intracranial ICA or MCA. STA-MCA bypass surgery in carefully selected patients results in significant improvement in hemodynamic parameters and reduction in stroke recurrence.

Brain tissue interaction with three-dimensional, honeycomb polycaprolactone-based scaffolds designed for cranial reconstruction following traumatic brain injury

Following traumatic brain injury (TBI), resultant voids are unable to support injections of suspension treatments, leading to ineffective healing. Moreover, without a structure to support the large defect, the defect site suffers from mechanical instability, which may impair the healing process. Therefore, having a delivery vehicle that can temporarily fill and provide mechanical support to the defect site may alleviate the healing process. In this work, we reported for the first time, the inflammatory response of brain tissue with polycaprolactone (PCL) and PCL-tricalcium phosphate (TCP) scaffolds designed and fabricated for cranial reconstruction. After cranial defects were created in Sprague-Dawley rats, PCL and PCL-TCP scaffolds were implanted for a period of 1 week and 1 month. Following histology and immunofluorescence staining with the ionized calcium binding adaptor molecule-1 (IBA-1), glial fibrillary acidic protein (GFAP), nestin, and neuronal nuclei (NeuN), results indicated that IBA-1-positive activated microglia were observed across all groups, and declined significantly by 1 month (p<0.05). Interestingly, IBA-1-positive microglia were significantly fewer in the PCL-TCP group (p<0.05), suggesting a relatively milder inflammatory response. A decrease in the number of GFAP-positive cells among all groups over time (>29%) was also observed. Initially, astrocyte hypertrophy was observed proximal to the TBI site (55% in PCL and PCL-TCP groups, 75% in control groups), but it subsided by 1 month. Proximal to the TBI site, nestin immunoreactivity was intense during week 1, and which reduced by 1 month across all groups. NeuN-positive neurons were shrunken proximal to the TBI site (<0.9 mm), 32% smaller in the PCL-TCP group and 27% smaller in the PCL group. Based on above data indicating the comparatively milder, initial inflammatory response of brain tissue to PCL-TCP scaffolds, it is suggested that PCL-TCP scaffolds have notable clinical advantages as compared to PCL scaffolds.

External ventricular drain infections: successful implementation of strategies to reduce infection rate

INTRODUCTION

External ventricular drain (EVD) infections can cause serious complications. We performed an audit of EVD infections within our neurosurgical unit. Through this study, we aimed to reduce the incidence of external ventricular drain-related infection, including ventriculities in neurosurgical patients.

METHODS

We conducted an audit of the EVD infections in our institution observed over a one-and-a-half year period. This was conducted in three phases. A baseline EVD infection rate was determined for Phase I, from January to June 2007. We introduced the following measures to reduce EVD infection rate in Phase II, from July to December 2007: (1) For Neurosurgery doctors: performing proper surgical techniques to minimise intra-operative infections; educating junior doctors on proper CSF sampling from the EVD; and minimising the number of days the EVD is maintained in situ; (2) For Neurosurgery nurse clinicians: developing Standard Operating Procedures on nursing management of EVDs; conducting EVD care workshops for nurses working in neurosurgical wards; and competency skill checks on the management of EVDs for nurses working in the neurosurgical wards. Silver-coated EVDs were introduced in Phase III of the study from January to June 2008.

RESULTS

The EVD infection rate decreased from a baseline of 6.1% to 3.8% in Phase II; a further reduction from 3.8% to 0% was achieved during Phase III.

CONCLUSION

Good teamwork among doctors and nurses is essential for reducing EVD infection rate. We managed to reduce EVD infections substantially and would continue to strive to remain infection-free in the future.

Detection of brain micrometastases by high-resolution stereotactic magnetic resonance imaging and its impact on the timing of and risk for distant recurrences

Object

The aim of this study was to assess the order of micrometastases that can be detected with high-resolution MR imaging at the time of Gamma Knife surgery (GKS), and to estimate the impact this has on the time until and incidence of distant recurrences.

Methods

A consecutive series of 835 patients with brain metastases treated with GKS in a 7-year period, excluding patients in whom earlier brain metastases were treated with other modalities, were retrospectively analyzed. In all patients GKS was based on high Gd–dose (0.3 mmol/kg), high-resolution stereotactic MR imaging. These images were compared with the standard pretreatment MR images, and the difference in number of metastases found was analyzed. The distant recurrence rate following GKS was compared with that found in a prospective randomized study (Aoyama et al.) comparing radiosurgery to radiosurgery plus prophylactic whole-brain radiation therapy.

Results

New tumors were diagnosed in 40% (95% CI 36%–43%) of all patients as well as in the majority of patients with multiple lesions found on the diagnostic scan. The more tumors there were on the diagnostic scan, the higher the likelihood of detecting additional lesions with high-resolution imaging. It was calculated that approximately 50% of the micrometastases present at the time of GKS could be diagnosed with high-resolution imaging, which decreased the incidence of and delayed the time for the development of distant recurrences.

Conclusions

Additional brain metastases can be diagnosed in 40% of patients by using high-resolution imaging. Thus, radiosurgical treatments based on high-resolution stereotactic MR imaging decrease the incidence of and lengthen the time to distant recurrences.

Migration of the abdominal catheter of a ventriculoperitoneal shunt into the mouth: a rare presentation

A 1-year-old boy with a history of exomphalos and hydrocephalus had surgeries to correct these pathologies. The ventriculopleural (VP(L)) shunt inserted for hydrocephalus was complicated by pleural effusion, for which a ventriculoperitoneal (VP) shunt was inserted on the contralateral side. He subsequently presented with protrusion of the distal VP shunt tip from the mouth due to perforation through the gastrointestinal tract. The child also had a history of peritonitis post-exomphalos repair, which may have predisposed him to this relatively uncommon shunt complication. Probable causes and risk factors of the perforation are discussed.

Correlation of the long-term neurological outcomes with completeness of surgical evacuation in spontaneous supratentorial intracerebral haemorrhage: a retrospective study

INTRODUCTION

The treatment of primary spontaneous supratentorial intracerebral haemorrhage (ICH) by evacuation is not supported by randomised controlled trials. We investigate the effectiveness of the completeness of surgical evacuation of spontaneous supratentorial ICH with respect to the functional neurological outcome and mortality.

METHODS

A retrospective review of patients who underwent supratentorial ICH evacuations in the Neurosurgical Unit of the National University Hospital, Singapore, between January 2002 and December 2005 was conducted. Preoperative and postoperative computed tomography images were compared, and the patients or their family members completed follow-up questionnaires two years post surgery, in order to assess the neurological outcome.

RESULTS

The patients were subdivided into two groups based on the Glasgow Outcome Scale and haematoma volume. Patients with small pre-evacuation haematoma had a median percentage change in volume and a midline shift of 97.63 percent and 63 percent, respectively. Patients with a large haematoma volume had a median percentage change in volume and midline shift of 99.54 percent and 100 percent, respectively (the p-values for percentage change in volume and midline shift are 0.764 and 0.742, respectively). The median percentage change in volume for the poor outcome subgroup was 97.63 percent, compared to 100 percent for the good outcome subgroup (p-value is 0.288). The median change in midline shift in the poor and good outcome subgroups was 63 percent and 100 percent, respectively (p-value is 0.576).

CONCLUSION

Although not statistically significant with regard to the completeness of haematoma evacuation, a trend toward better outcome with more complete evacuation is observed with ICH.

Use of Osteoplug polycaprolactone implants as novel burr-hole covers

INTRODUCTION

The aim of this study was to evaluate the outcome of Osteoplug, a novel biodegradable polymer burr-hole cover implant, used in patients with burr holes done for drainage of chronic subdural haematoma.

METHODS

12 patients with chronic subdural haematoma had Osteoplug implants inserted into their burr holes after evacuation of the haematoma. Osteoplug is a biodegradable polycaprolactone implant with a mushroom-button shape, designed specifically to fit into a 14-mm diameter burr hole. It has an upper rim of 16-mm diameter and a body diameter of 14 mm, with a honeycomb-like architecture of 400-600 mum pore size. The Osteoplug snaps onto the 14-mm diameter burr hole snugly after the evacuation of the liquefied haematoma is done. All 12 patients were followed up for a period ranging from ten months to two years (mean 16 months) postoperatively. They were evaluated for their clinical, radiological and cosmetic outcomes.

RESULTS

Osteoplug provided good cosmesis by preventing unsightly depressions over the skull postoperatively in all the 12 patients. Postoperative computed tomography, done at one year, showed signs of good osteointegration into the surrounding calvarial bone, with multifoci mineralisation throughout the scaffold in one patient. There was no case of infection or any adverse systemic reaction noted. Patient satisfaction was high.

CONCLUSION

The Osteoplug polycaprolactone burr-hole covers are suitable, biodegradable implants with good medium-term results. They provide an ideal scaffold for osteogenesis and excellent cosmesis. There were no adverse events in all 12 patients, with a mean follow-up of 16 months.

Repair of Calvarial Defects with Customised Tissue-Engineered Bone Grafts II. Evaluation of Cellular Efficiency and Efficacyin Vivo

We have demonstrated in Part I of this study [see Schantz, J.-T., et al., Tissue Eng. 2003;9(Suppl. 1): S-113-S-126; this issue] that bone marrow-derived progenitor cells and calvarial osteoblasts could be successfully directed into the osteogenic lineage and cultured in three-dimensional (3-D) polycaprolactone (PCL) scaffolds. The objective of the second part of the study was to evaluate and to compare tissue engineered cell-polymer constructs using calvarial osteoblasts (group I) and mesenchymal progenitor cells (MPCs; group II) for the reconstruction of critical-size and three-dimensionally complex cranial defects. In 30 New Zealand White rabbits, bilateral parietal critical-size defects were created. On the basis of computed tomography scans, customized PCL scaffolds with precisely controlled microarchitecture were fabricated, using a rapid prototyping technology. Bone marrow-derived progenitor cells and osteoblasts were isolated and expanded in culture. Osteoblasts (group I) and mesenchymal progenitor cells (group II) were seeded in combination with a fibrin glue suspension into 40 PCL scaffolds. After incubating for 3 days in static culture, the PCL scaffold-cell constructs as well as nonseeded PCL scaffolds (control group) were implanted into 15-mm-diameter calvarial defects. Reconstruction of the cranium and bone formation were evaluated after 3 months. In vivo results indicated osseous tissue integration within the implant and functionally stable restoration of the calvarium. Islands of early bone formation could be observed in X-ray radiographs and in histological sections. Implants showed a high cell:ECM ratio and a dense vascular network. Mechanical testing of the reconstructed area revealed partial integration with the surrounding corticocancellous calvarial bone. The amount (area) of calcification, measured by clinical computed tomography, indicated that cell-seeded constructs measured about 60% more than unrepaired or unseeded scaffolds. Mechanical investigations revealed that stiffness reached 52 +/- 29 and 44 +/- 16 MPa for MPC- and osteoblast-seeded scaffolds, respectively. The yield strength for the push-out tests was 180 +/- 36 N for normal calvarial bone, 90 +/- 1 N for unrepaired site, and 106 +/- 10 N for unseeded constructs, which is about 60% of normal bone strength. MPC- and osteoblast-seeded scaffolds indicated a yield strength of 149 +/- 15 and 164 +/- 42 N, respectively, which is about 85-90% of normal bone. This study demonstrated that customized biodegradable polymeric implants may be used to deliver osteogenic cells and enhance bone formation within critically-sized defects in vivo. The use of rapid prototyping technology to produce scaffolds with controlled external geometry and microarchitecture offers new possibilities in the functional and aesthetic reconstruction of complex craniofacial defects.

Giant aneurysm treated by bilateral cervical carotid artery to proximal middle cerebral artery bypass and balloon embolisation: a case report

The authors describe a case of a 59 year-old Chinese lady with a history of spontaneous left caroticocavernous fistula in 1988 treated by left internal carotid artery clipping and muscle embolisation. She subsequently presented with a subarachnoid haemorrhage in November 1997 secondary to rupture of an unclippable giant right internal carotid artery aneurysm. This was treated satisfactorily with bilateral cervical carotid artery to proximal middle cerebral artery bypass followed by balloon occlusion. Postoperatively, the patient has no neurological deficit and CT angiogram shows good patency of both grafts 6 months after surgery.

Identification of human, rat and mouse nocistatin in brain and human nocistatin in brain and human cerebrospinal fluid

Nocistatin was recently isolated from bovine brain and shown to block hyperalgesia and allodynia induced by nociceptin and prostaglandin (PG) E2. The counterparts of human, rat and mouse are deduced from their precursor prepronociceptin to be 30, 35, and 41 residue peptide respectively. To identify these mature forms of nocistatin, three peptides were synthesized and a detection program for nocistatin was developed, using high pressure liquid chromatography (HPLC) along with specific radioimmunoassay (RIA). Nocistatin extracted from human, rat and mouse brain were subjected to HPLC and nocistatin-like immunoreactivity (NST-IR) was determined. All three species showed two NST-IR peaks, one of which coincided with that of the corresponding putative nocistatin. The same NST-IR was also detected in human cerebrospinal fluid (CSF).

[Linac-based stereotactic radiosurgery for arteriovenous malformations (AVMs) in brain: estimation for efficacy of therapeutic response using angiography]

The purpose of this study was to determine whether it is possible to predict the efficacy of therapeutic response to linac-based stereotactic radiosurgery for AVMs on the basis of the stagnation rate in the nidus, which was defined as follows: [(pooling time of contrast material in the nidus of AVM)/ (intracranial circulation time)] x 100. Cerebral angiograms of twenty-five AVMs were retrospectively evaluated, and the stagnation rates in the nidus were calculated before and one year after stereotactic radiosurgery. Reduction rate was also calculated by using angiography, and we statistically evaluated the relationship between the stagnation rates in the nidus and the reduction rates. The stagnation rates in the nidus prior to linac-based stereotactic radiosurgery were positively correlated with the reduction ratios of AVMs after stereotactic radiosurgery (r = 0.406, p = 0.0432). Our study suggested that a higher stagnation rate in the nidus of the AVM might be obliterated faster after linac-based stereotactic radiosurgery. Thus, calculation of the stagnation rate in the nidus before stereotactic radiosurgery is useful in predicting the efficacy of therapeutic response to linac-based stereotactic radiosurgery for AVMs.