Feasibility of anaesthetic provision for paediatric patients undergoing off-site intraoperative MRI-guided neurosurgery: the Singapore experience from 2009 to 2012.

The benefits of using intraoperative magnetic resonance imaging (iMRI) for neurosurgery have been recognised. However, iMRI facilities are not available in all hospitals. For example, in Singapore iMRI is currently available only at the Singapore General Hospital, an adult hospital without facilities for intensive care management of patients less than 12 years of age. KK Women's and Children's Hospital is a dedicated children's hospital situated 6.3 km away from this facility. In order to obtain iMRI services for our paediatric patients, transport to Singapore General Hospital is required, with return to our hospital for postoperative management. Since July 2009 we have managed nine paediatric patients in this manner: three children with arteriovenous malformations and six children with brain tumours. There was no morbidity or mortality that could be attributed to the transport of patients either to or from Singapore General Hospital. Our experience suggests that with adequate planning and preparation, providing anaesthetic care and transporting children for off-site iMRI-guided neurosurgery is feasible and safe for selected children.

Comparing histopathological classification with MYCN, 1p36 and 17q status detected by fluorescence in situ hybridisation from 14 untreated primary neuroblastomas in Singapore.

INTRODUCTION: Neuroblastoma is the most common extracranial solid tumour in children, accounting for about 5.3 percent of all childhood cancers in Singapore. Several genetic abnormalities have been reported as prognostic markers, including amplification of the MYCN gene, deletion of the short arm of chromosome 1 (1p) and gain of the long arm of chromosome 17 (17q). However, the correlation between tumour histology and these genetic parameters remains to be established in our local population. METHODS: 14 untreated primary neuroblastoma tumours, diagnosed consecutively in our hospital between 2003 and 2007, were included for this study. Tumour tissues were classified histologically as favourable or unfavourable, according to the modification of World Heath Organization Classification of Tumours, by associating the degree of differentiation and mitotic-karyorrhectic index of the neuroblastoma to the age of the patient. Fluorescence in situ hybridisation analysis for MYCN, 1p status and 17q status were subsequently performed on tumour touch imprints. RESULTS: Five tumours with favourable histology were all negative for the three genetic parameters being investigated. The other nine tumours showing unfavourable histology exhibited one or more of the three genetic parameters. All MYCN amplified tumours either had additional 1p deletion and/or 17q gain. CONCLUSION: Our limited data suggests that 1p deletion and 17q gain are reliable independent parameters correlating with an unfavourable histology and poor clinical outcome. The use of 1p deletion and 17q gain studies, in addition to MYCN amplification studies, should be considered routinely in predicting prognosis in neuroblastomas.

'Moya' than meets the eye: neurofibromatosis type 1 associated with Moyamoya syndrome.

Moyamoya syndrome (MMS) is an uncommon association of neurofibromatosis type 1 (NF1). We describe a seven-year-old chinese girl with NF1 and unilateral MMS with multiple hyperintensities on T2-weighted magnetic resonance (MR) images. The ischaemic lesions in the ipsilateral white matter were hypointense on fluid attenuated inversion recovery (FLAIR) MR images, in contrast to the hyperintense "unidentified bright objects" (UBOs) of NF1. Neuroradiologists should be aware of associated MMS in NF1 patients, and distinguish the effects of ischaemia from UBOs, especially on FLAIR MR imaging.

Barbiturate therapy for patients with refractory intracranial hypertension following severe traumatic brain injury: its effects on tissue oxygenation, brain temperature and autoregulation.

The aim of this study was to explore the effects of barbiturate coma on cerebral tissue oxygen tension and cerebrovascular pressure reactivity (PRx), as an index of cerebral autoregulation in severe head injury patients. This was a prospective observational clinical study of 12 patients with severe traumatic brain injury, carried out at a tertiary-level neurosurgical intensive care unit between April 2002 and May 2005. All patients received standard neurosurgical intensive care and monitoring. Probes for intracranial pressure (ICP), brain temperature (BT) and brain tissue oxygenation (PTiO2) were inserted into (noncontused) normal-looking white matter. Cerebrovascular PRx was measured as a moving correlation between ICP and arterial blood pressure. Barbiturate coma was instituted when ICP became refractory (ICP>20 mmHg). All data from the multimodal monitoring were digitally extracted and statistically analysed. The mean ICP decreased with barbiturate coma in eight of the 12 patients (75% of the patients), but only four achieved a value below 20 mmHg. Of eight patients with prebarbiturate PTiO2 levels above 10 mmHg, six had a further improvement in oxygenation. Thus, concordant favourable changes in ICP, PRx and PTiO2 with barbiturate coma were seen in those who survived. Effective response to barbiturates can be detected by improved PTiO2 and autoregulation (PRx) in severe head injury patients.

Paediatric PNET: pre-surgical MRI features.

AIM: To describe the preoperative magnetic resonance imaging (MRI) characteristics of primitive neuroectodermal tumours (PNETs), in particular the diffusion-weighted imaging (DWI), MR spectroscopy (MRS) features and cerebrospinal fluid (CSF) tumour dissemination. MATERIAL AND METHODS: Twelve patients with PNETs were reviewed: nine with medulloblastoma and three with supratentorial PNETs (SPNETs). The MRI examination included contrast-enhanced intracranial and spinal MRI, and in some patients, gradient recalled echo, fluid-attenuated inversion recovery (FLAIR), DWI, and MRS. RESULTS: All PNETs were either hypointense or isointense on T1-weighted images. Ten of the 12 tumours were either isointense or hypointense on T2-weighted images, and 11 were isointense on FLAIR images. Patients with SPNETs had large, vascular and haemorrhagic tumours. On DWI, all PNETs were hyperintense and had restricted apparent diffusion coefficient. MRS (two patients with medulloblastoma and one with a SPNET), showed elevated choline, decreased N-acetyl aspartate, and a small taurine peak in all three patients. Intraspinal tumour dissemination, visible as uniform or nodular enhancement coating the conus medullaris, was detected in six of 12 patients, two of whom also had intracranial dissemination. CONCLUSION: PNETs have a characteristic imaging appearance on FLAIR, DWI and MRS, which may help in differentiating these highly cellular neoplasms from other tumours. There is CSF tumour dissemination in a high proportion of patients, and spinal imaging is important for disease staging and to formulate treatment protocols.

Demographical profiles of adult severe traumatic brain injury patients: implications for healthcare planning.

INTRODUCTION: In Singapore, severe traumatic brain injury (TBI) continues to be a major public health problem and devastating condition, with significant mortality and morbidity. By understanding the incidence, prevalence and implications of severe TBI in Singapore, strategic plans to meet the unique needs of these patients in the local context may be developed. METHODS: The demographical profiles of the adult severe TBI patients in Singapore were studied in this retrospective review of 528 patients admitted to the National Neuroscience Institute (NNI) from January 1999 to December 2003. RESULTS: There were 420 male and 108 female patients, age ranging from 15 to 96 years old, with a mean and standard deviation (SD) of 44.6 +/- 19.9 years, admitted to NNI during the study period. Motor vehicle and fall-related accidents were the leading causes of severe TBI. Three high-risk groups identified were young adults, elderly, and foreign workers. CONCLUSION: Preventive measures targeting at these high-risk groups are important to reduce the incidence of severe TBI.

Dural sinus thrombosis after minor head injury in a child.

INTRODUCTION: Dural sinus thrombosis following minor head injury is rare. We report such a case in a child after mild head injury. CLINICAL PICTURE: A 4-year-old child presented with giddiness and vomiting after a fall. Clinical examination was unremarkable. Magnetic resonance venogram revealed thrombosis of the right sigmoid and transverse sinuses. TREATMENT: The patient was managed conservatively. OUTCOME: Repeat scans 10 weeks after injury showed recanalisation of the thrombosis. CONCLUSION: Dural sinus thrombosis should be excluded in children presenting with persistent giddiness and vomiting after minor head injury.

Characteristics of six newborn infants with postnatal findings of severe intracranial haemorrhage.

OBJECTIVE: The objective of this study was to study the characteristics of newborn infants with postnatal findings of severe neonatal intracranial haemorrhage. METHODS: All the records of babies who underwent surgery from 1997 to 2002 for intracranial haemorrhage were reviewed. These were correlated with their antenatal records to see if fetal intracranial haemorrhage had been detected at the 20 weeks' screening scan or any other incidental scan e.g. growth scan. The perinatal records were also reviewed to see if there was associated birth trauma such as instrumentation or obstetric manoeuvres at delivery. RESULTS: Six cases of severe intracranial haemorrhage were diagnosed postnatally. Of these, only 1 case was detected antenatally on ultrasound scan. None of the cases were due to birth trauma. Three babies were found to have clotting factor deficiency. One of them subsequently developed cerebral palsy. One baby was diagnosed to have alloimmune thrombocytopenia. One case underwent an emergency Caesarean section for non-reassuring fetal status. Extensive intracranial haemorrhage, attributed to hypoxia, was found. The baby died. CONCLUSIONS: Our study suggests that neonatal intracranial haemorrhages are not exclusively due to birth trauma. The study also shows that fetal intracranial haemorrhage may not be detected antenatally by the routine practice. The causes in our study included clotting deficiency, alloimmune thrombocytopenia and hypoxia.

Non-traumatic spontaneous acute epidural haematoma -- report of two cases and review of the literature.

Epidural haematomas are usually associated with preceding head trauma. The entity of non-traumatic spontaneous acute epidural haematoma is rare and most commonly occurs in the presence of infectious disease. It can also occur in the presence of coagulopathy, vascular malformations of the dura mater and haemorrhagic tumours. Sickle cell disease, systemic lupus erythematosus, open heart surgery and haemodialysis have also been implicated as causative factors. The authors report two cases of spontaneous epidural haematomas (one of unknown aetiology and one from a coagulation disorder) and discuss the aetiological agents involved in this rarely described condition.

Intracerebral schwannoma--a rare cause of epilepsy.

INTRODUCTION: We report a case of schwannoma occurring in an intra-axial location causing seizures. CLINICAL PICTURE: A 13-year-old girl presented with a 4-month history of seizures. Preoperative computed tomography scan and magnetic resonance imaging revealed an enhancing right frontal lobe tumour with surrounding oedema. TREATMENT: The patient underwent craniotomy and a well-circumscribed tumour was completely resected. Histology with immunohistochemistry confirmed the diagnosis of an intracerebral schwannoma. OUTCOME: The patient made a complete recovery and was seizure-free at 1-year follow-up. CONCLUSION: Intracerebral schwannomas are rare, benign tumours. They may mimic astrocytomas or malignant tumours, and it is important to differentiate them from other neoplasms with less favourable outcomes. The neuroimaging features are, however, non-specific and definitive diagnosis can only be made on histology.

Tethered cord syndrome preceding syrinx formation--serial radiological documentation.

The authors report a case of tethered cord syndrome preceding the development of a syrinx, which subsequently resolved with detethering. This was shown conclusively with serial radiological imaging, although the patient did not improve clinically. The lack of clinical improvement is likely to be due to the delay in surgery caused by infections in this patient, and early detethering should therefore be the aim in patients with tethered cord syndrome.

Childhood temporal bone osteoblastoma: a case report.

Osteoblastoma is a rare primary tumor of the bone. Its sites of predilection are the vertebrae and the long bones. Occurrence in the skull is rare. The authors describe an unusual case of osteoblastoma occurring in the temporal bone of a child. Interestingly, although the clinical and radiological features were suggestive of an aggressive lesion, the histological features were consistent with that of a benign tumor. Although generally regarded as benign, osteoblastoma has potential for recurrence, local invasion, and, rarely, malignant transformation. As such, complete resection, whenever possible, is preferred over conventional curettage.

Spontaneous subarachnoid haemorrhage and outcome--results from Tan Tock Seng Hospital, Singapore.

AIM OF STUDY: To ascertain the number of cases of spontaneous (aneurysmal) subarachnoid haemorrhage presenting to Tan Tock Seng Hospital, Singapore, over a one year period, the demographics of the patients involved, their treatment and their eventual outcome. METHOD: A retrospective study from June 1995 to June 1996. RESULTS: There were 62 patients admitted over this period with an average of 5 patients per month. Their ages ranged from 9 to 85 years with a mean of 54 years. All 62 patients underwent 4-vessel cerebral angiograms. Forty-three patients (69%) underwent clipping of their aneurysms. Twelve patients (19%) had negative angiograms. Four patients (6%) underwent coiling of their aneurysms via interventional neuroradiology techniques. Patients with subarachnoid haemorrhage of Grades 1 to 3 on the WFNS (World Federation of Neurological Surgeons) grading had a favourable outcome (Glasgow Outcome Score of 4 and 5) in 85% of the cases. The overall mortality rate for the operated group (all grades) was 11%. However for the group with good WFNS grading, namely the Grade 1 to 2 groups, there were no deaths. Twenty-four percent of patients developed clinically symptomatic vasospasm. Eighteen percent of patients required ventriculo-peritoneal shunting for hydrocephalus secondary to the subarachnoid haemorrhage. The overall management mortality (operated and non-operated cases) was 14% for proven aneurysmal and angiographically-negative spontaneous subarachnoid haemorrhage. These results are comparable to that of other reputable centers reported in the literature.

Outcome of patients with traumatic brain injury managed on a standardised head injury protocol.

A standardised protocol in the management of severe head injury in our hospital enables pre-determined critical care-paths and consistent treatment regimes to be instituted. In Singapore there has been no previously reported data on the outcome of severely head injured patients. Over a 6-month period, 48 consecutive patients who were enrolled in our severe head injury protocol were prospectively studied. In addition to demographic and outcome data, physiologic measurements obtained from a computerised patient information system (Carevue Hewlett-Packard 9000) were analysed to determine the mean cerebral perfusion pressure (CPP) and intracranial pressure (ICP) achieved throughout the protocol period. Median Glasgow Coma Score for all patients on admission to the protocol was 6 (range 4 to 8). The mean age was 34.46 +/- 15.03 years with a male to female ratio of 43:5. The average duration of treatment on the protocol was 110.73 hours. Initial ICP measured was 25.5 +/- 19.68 mmHg. Outcome was measured at 6 months post-injury using the Glasgow Outcome Score. Favourable outcome (GOS 4-5) was seen in 29 of 48 patients (60.4%) while 12 out of 48 (25%) had an unfavourable outcome. There was a mortality of 14.6% (7 of 48 patients). Patients who survived had a higher mean CPP (P = 0.00005), a lower initial ICP and a mean ICP (P = 0.007 and 0.0009). The use of a protocol with standardised treatment goals in the management of traumatic brain injury allows for the optimal use of limited resources and provides consistency in treatment. Good outcome is related to early aggressive resuscitation to prevent hypotension and hypoxia, prompt evacuation of surgical mass lesions and the maintenance of an adequate cerebral perfusion pressure. Our results are comparable with that reported in other established neurotrauma systems.

A study on the efficacy of intraventricular urokinase in the treatment of intraventricular haemorrhage.

Twenty-one patients with intraventricular haemorrhage were randomized to two treatment groups. Both groups had bilateral external ventricular drains inserted, but only the treatment group received 50,000 IU urokinase instilled into the ventricles. The clinical and radiological progress, and 1- and 6-month outcomes were compared. The group that received urokinase treatment was shown to have an improved outcome, with a lower mortality and a lower incidence of hydrocephalus requiring shunt insertion. No haemorrhagic complications were seen in either group, although the treatment group had a slightly increased rate of drain-related ventriculitis.

Leptomeningeal metastasis with urological presentation.

The incidence of clinical leptomeningeal metastases from non-neurologic solid tumour is generally increasing as a result of better survival of systemic cancer with chemotherapy. Their presentation varies according to the neurological involvement. A case of leptomeningeal metastasis from an unknown primary source presenting with urinary incontinence as the sole complaint is reported. While urinary incontinence is common in the community and is often functional, neurogenic causes must also be considered. Urodynamic study and electrophysiological assessment are useful investigations in the exclusion of a neurogenic cause. An MRI of the spine will be required to define any anatomic lesion.

Brain abscesses: review of 30 cases treated with surgery.

Thirty patients with brain abscesses who were treated at the Department of Neurosurgery, Tan Tock Seng Hospital, Singapore, during the period July 1989 to July 1993, were reviewed. There were seven females and 23 males with mean follow up duration of 19 months. The predisposing factors identified were otogenic infections in 10 cases (33%), paranasal sinus infection in 2 cases (7%) and congenital heart disease in 6 cases (20%). All cases underwent aspiration or excision of the abscess. Repeat operations were carried out if the abscess reaccumulated. A total of 49 aspirations and 16 excisions were performed. Twenty-five patients (84%) made a good recovery, three patients (10%) were moderately disabled, one patient (3%) was severely disabled and one patient (3%) died. There was no postoperative haemorrhage or wound infections. Two patients (7%) developed hydrocephalus and three (10%) had seizures postoperatively.

Surgery for brain metastases in Singapore.

The best possible treatment for a single metastasis to the brain is complete surgical excision followed by whole brain irradiation. A survey was done to determine the proportion of patients with brain metastases who had surgical excision of the lesion. The number of patients with a preoperative diagnosis of cerebral metastases who underwent surgical excision in Tan Tock Seng Hospital from 1985 to 1989 was obtained from the operation records. An average of 11 surgical excisions were done for cerebral metastases annually. To estimate the number of cases of single brain metastases seen annually in Singapore, figures of cases of cancer of the lungs, breast and colorectum from 1978 to 1982 were obtained from the Singapore Cancer Registry. Based on a conservative estimate that 20% of these cancers metastasize to the brain, that 50% are single metastasis and of these, half are suitable surgical candidates, our calculations show that there are at least 67 cases of surgically excisable single brain metastasis in Singapore annually. This means that more than 84% of patients with a single brain metastasis are not getting the best possible treatment. The reasons may be due to patients' fear of operation and to lack of awareness among physicians on advances in the management of brain metastases. Patient education and physician update on recent advances in treatment will allow patients to obtain the best possible treatment.

Tuberculoma of the brain--report of 2 cases and review of literature.

Tuberculomas of the brain are relatively uncommon in developed countries nowadays. We report the only two cases that were seen in our Department in the last five years. Both patients presented with seizures and were found to have space occupying lesions on cranial CT scanning. They had no past history of tuberculosis, no evidence of current extracranial tuberculosis and the diagnosis of tuberculoma was made at the time of surgical excision. Underdiagnosis of tuberculoma of the brain is likely to occur in industrialised countries where tuberculosis is rare. The radiological investigation of choice is CT scanning with contrast enhancement and the presence of a target lesion is considered to be pathognomonic of a tuberculoma. Most tuberculomas of the brain can be treated medically with antituberculous chemotherapy. We recommended obtaining a definitive histological diagnosis with CT-guided stereotactic techniques prior to commencing antituberculous therapy. Surgical excision is necessary in patients with raised intracranial pressure secondary to the lesion and not responding to medical therapy.

CT-directed BRW stereotactic neurosurgery: local experience with 42 cases.

Initial experience with the Brown-Roberts-Wells (BRW) computed tomographic (CT)-guided stereotactic system is reported. Forty-two procedures were performed over a 22-month period on 21 female and 20 male patients (one patient had a repeat procedure). Their ages ranged from 11 years to 89 years. These included 21 stereotactic biopsy procedures, 2 stereotactic implantations of third ventricular catheters through the foramen of Monro for intraventricular opiate insertion in terminal cancer patients, 2 stereotactic aspirations for brain abscess, 10 stereotactic aspirations of intracerebral haematomas, 3 stereotactic aspirations of cystic brain tumours, 1 stereotactic placement of a fourth ventricle-peritoneal shunt and lastly 3 stereotactic craniotomies. Successful targeting was achieved in all cases. There was one operation-related complication which resulted in uncontrollable intracerebral haemorrhage and ultimately led to the patient's demise.