Wai Hoe Ng

Outcomes of chronic subdural hematoma drainage in nonagenarians and centenarians: a multicenter study

OBJECTIVEnChronic subdural hemorrhage (SDH) or hematoma is a condition that affects elderly individuals. With advances in medical care, the number of nonagenarians and centenarians will increase. However, surgical treatments in this age group are associated with high rates of morbidity and mortality. Because no data are available on the rates of survival among elderly patients with chronic SDHs who undergo surgical drainage or receive only conservative care, the goal of this study was to determine survival rates in patients 90 years of age or older with symptomatic chronic SDHs.nnnMETHODSnThe authors conducted a retrospective analysis of patient data that were collected at 3 hospitals over a 13-year period (from January 2001 to June 2013). The data from patients 90 years or older with symptomatic chronic SDHs and who were offered surgical treatment were included in the analysis. Patients who underwent surgical treatment were included in the surgical group and patients who declined an operation were included in the conservative care group. The patients Charlson Comorbidity Index score, Karnofsky Performance Scale score, dates of death, presenting symptoms, Glasgow Coma Scale score, length of stay in the hospital, discharge location, side of the SDH, and neurological improvements at 30-day and 6-month follow-ups were recorded. Data were statistically analyzed with Fisher exact test, Kaplan-Meier curves, and logistic regression.nnnRESULTSnIn total, 101 patients met the inclusion criteria of this study; 70 of these patients underwent surgical drainage, and 31 received conservative care. Patients in the surgical group had statistically significantly (p < 0.001) higher survival at both the 30-day and 6-month follow-ups, with 92.9% and 81.4% of the patients in this group surviving for at least 30 days and 6 months, respectively, versus 58.1% and 41.9%, respectively, in the conservative care group. Moreover, the mean overall length of survival of 34.4 ± 28.7 months was longer in the surgical group than it was in the conservative care group (11.3 ± 16.6 months). Overall, 95.7% of patients in the surgical group exhibited an improvement in neurological status after the SDH drainage, whereas none of the patients in the conservative care group showed any neurological improvement during their hospital stay. The surgical complication rate was 11.4%, and the overall rate of chronic SDH recurrence after surgery was 12.9%.nnnCONCLUSIONSnSurgical drainage of chronic SDHs in nonagenarians and centenarians is associated with lower incidence of inpatient death and higher 30-day and 6-month survival rates.

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.

MicroRNA as potential modulators in chemoresistant high-grade gliomas

Gliomas account for 70% of human malignant primary brain tumours. The most common form is glioblastoma multiforme, World Health Organization grade IV. Despite the implementation of post-operative adjuvant radiotherapy with concurrent temozolomide (TMZ), the diseases overall prognosis remains dismal. TMZ is currently the only mono-chemotherapeutic agent for newly-diagnosed high-grade glioma patients and acquired resistance inevitably occurs in the majority of such patients, further limiting treatment options. Therefore, there is an urgent need to better understand the underlying mechanisms involved in TMZ resistance, a critical step to developing effective, targeted treatments. An emerging body of evidence suggests the intimate involvement of a novel class of nucleic acid, microRNA (miRNA), in tumorigenesis and disease progression for a number of human malignancies, including primary brain tumours. miRNA are short, single-stranded, non-coding RNA (∼22 nucleotides) that function as post-transcriptional regulators of gene expression. This review provides an overview of the key treatment obstacles faced in patients with high-grade gliomas, especially in the context of recurrent, chemoresistant tumours and the potential roles of miRNA in chemoresistance and management of this disease.

Assessment of neurovascular dynamics during transient ischemic attack by the novel integration of micro-electrocorticography electrode array with functional photoacoustic microscopy

This study developed a novel system combining a 16-channel micro-electrocorticography (μECoG) electrode array and functional photoacoustic microscopy (fPAM) to examine changes in neurovascular functions following transient ischemic attack (TIA) in rats. To mimic the pathophysiology of TIA, a modified photothrombotic ischemic model was developed by using 3 min illumination of 5 mW continuous-wave (CW) green laser light focusing on a distal branch of the middle cerebral artery (MCA). Cerebral blood volume (CBV), hemoglobin oxygen saturation (SO2), somatosensory evoked potentials (SSEPs) and alpha-to-delta ratio (ADR) were measured pre- and post-ischemia over a focal cortical region (i.e., 1.5×1.5 mm(2)). Unexpectedly, the SO2, peak-to-peak amplitude (PPA) of SSEPs and ADR recovered and achieved levels greater than the baseline values at the 4th hour post-ischemia induction without any intervention, whereas the CBV value only partially recovered. In other words, transient ischemia led to increased neural activity when the relative CBV was reduced, which may further compromise neural integrity or lead to subsequent vascular disease. This novel μECoG-fPAM system complements currently available imaging techniques and represents a promising technology for studying neurovascular coupling in animal models.

Combined temozolomide and radiation as an initial treatment for anaplastic glioma

Combined temozolomide (TMZ) and radiation therapy (RT) is often used as initial treatment for anaplastic glioma. However, there is no prospective randomized data available that proves the efficacy of the combination for anaplastic glioma. In this retrospective study we aimed to compare the outcome of patients who had combined TMZ and RT with those who had RT alone for the initial treatment of anaplastic glioma in our centers.

Value of routine early post-operative computed tomography in determining short-term functional outcome after drainage of chronic subdural hematoma: An evaluation of residual volume

Background: Computed tomography (CT) scans are widely used in managing chronic subdural hematoma (CSDH). Factors that determine early post-operative volume have not been examined. The value of routine early post-operative residual volume have not been evaluated. Our study aims to compare pre-operative and early post-operative CT findings to determine the factors affecting residual hematoma and evaluate if early post-operative CT scans are useful in the management of CSDH. Methods: Forty-three patients who underwent burr hole drainage of unilateral CSDH from August 2006 to January 2013 and had routine post-operative CT scans within 48 hours of surgery were selected. Data regarding age, sex, neurological deficit, Glasgow Coma Scale (GCS), pre-existing medical conditions, use of antiplatelets or anticoagulation, operative time, usage of drains, and number of burr holes were obtained. The pre-operative CSDH volume, CSDH density, and midline shift were measured. Residual volume was calculated from early post-operative CT scans. Clinical outcome was evaluated with Glasgow Outcome Scale (GOS) at the time of discharge. Statistical analysis was performed to look for correlation between the pre-operative factors and residual volume, and the residual volume and GOS. Results: Pre-operative volume was found to correlate significantly with post-operative residual volume. There was no significant correlation between all other pre-operative factors and residual volume. There was also no correlation between residual volume and GOS at discharge. Conclusion: Routine post-operative CT brain for burr hole drainage of CSDH may be unnecessary in view of the good predictive value of pre-operative volume, and also because it is not predictive of the clinical outcome.

Investigation of the usefulness of fluorescein sodium fluorescence in stereotactic brain biopsy

BackgroundIntraoperative frozen section assessment, to confirm acquisition of pathological tissues, is used in stereotactic brain biopsy to minimise sampling errors. Limitations include the dependence on dedicated neuro-oncology pathologists and an increase in operative duration. We investigated the use of intraoperative fluorescein sodium, and compared it to frozen section assessment, for confirming pathological tissue samples in the stereotactic biopsy of gadolinium-contrast-enhancing brain lesions.MethodsThis prospective observational study consisted of 18 consecutive patients (12 men; median age, 63xa0years) who underwent stereotactic biopsy of gadolinium-contrast-enhancing brain lesions with intravenous fluorescein sodium administration. Twenty-three specimens were obtained and examined for the presence of fluorescence using a microscope with fluorescence visualisation capability. Positive and negative predictive values were calculated based on the fluorescence status of the biopsy samples with its corresponding intraoperative frozen section and definitive histopathological diagnosis.ResultsNineteen specimens (83%) were fluorescent and four (17%) were non-fluorescent. All 19 fluorescent specimens were confirmed to be lesional on intraoperative frozen section assessment and were suitable for histopathological diagnosis. Three of the non-fluorescent specimens were confirmed to be lesional on intraoperative frozen section assessment. One non-fluorescent specimen was non-diagnostic on frozen section and histological assessments. The positive predictive value was 100% and the negative predictive value was 25%.ConclusionsFluorescein sodium fluorescence is as accurate as frozen section assessment in confirming sampling of pathological tissue in the stereotactic biopsy of gadolinium-contrast-enhancing brain lesions. Fluorescein sodium fluorescence-guided stereotactic biopsy is a useful addition to the neurosurgical armamentarium.

Integrated treatment modality of cathodal-transcranial direct current stimulation with peripheral sensory stimulation affords neuroprotection in a rat stroke model

Abstract. Cathodal-transcranial direct current stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral sensory stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation (SO2) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatosensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the (delta+theta)/(alpha+beta) ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.

The Fluoropen: a simple low-cost device to detect intraoperative fluorescein fluorescence in stereotactic needle biopsy of brain tumors

BackgroundThe use of fluorescein fluorescence-guided stereotactic needle biopsy has been shown to improve diagnostic accuracy and to expedite operative procedure in the stereotactic needle biopsy of high-grade gliomas. We developed a device (Fluoropen) for detecting fluorescence in brain tumor tissues obtained by fluorescein fluorescence-guided stereotactic needle biopsy.MethodsThe Fluoropen is a device consisting of a light source fitted with color filters to create the required emission and visualization wavelengths. The proof-of-concept study consisted of four consecutive patients who underwent fluorescein fluorescence-guided frameless stereotactic biopsy of brain tumor. Each sample was examined for the presence of fluorescence using the Fluoropen and compared with a microscope with fluorescence visualization capability.ResultsA total of six samples were obtained from four stereotactic needle biopsy procedures. Four out of five samples (80%) taken from the contrast-enhancing part of the tumors were shown to be fluorescent under the microscope fitted with fluorescence module and the Fluoropen. One non-contrast enhancing lesion was non-fluorescent using both the microscope fitted with fluorescence module and the Fluoropen. The Fluoropen was shown to have 100% concordance with the microscope fitted with fluorescence module.ConclusionsThe Fluoropen is a low-cost and simple standalone device for the detection of fluorescein fluorescence that can expedite stereotactic needle biopsy by providing instant confirmation of the diagnostic sample and therefore avoid the need for an intraoperative frozen section. In patients with non-contrast enhancing tumors and those who were pre-treated with dexamethasone prior to surgery, fluorescein fluorescence-guided stereotactic needle biopsy will need to be used with caution.

A computed tomography morphometric study of occipital bone and C2 pedicle anatomy for occipital-cervical fusion

Background: Occipital-cervical fusion (OCF) has been used to treat instability of the occipito-cervical junction and to provide biomechanical stability after decompressive surgery. The specific areas that require detailed morphologic knowledge to prevent technical failures are the thickness of the occipital bone and diameter of the C2 pedicle, as the occipital midline bone and the C2 pedicle have structurally the strongest bone to provide the biomechanical purchase for cranio-cervical instrumentation. The aim of this study was to perform a quantitative morphometric analysis using computed tomography (CT) to determine the variability of the occipital bone thickness and C2 pedicle thickness to optimize screw placement for OCF in a South East Asian population. Methods: Thirty patients undergoing cranio-cervical junction instrumentation during the period 2008-2010 were included. The thickness of the occipital bone and the length and diameter of the C2 pedicle were measured based on CT. Results: The thickest point on the occipital bone was in the midline with a maximum thickness below the external occipital protuberance of 16.2 mm (±3.0 mm), which was thicker than in the Western population. The average C2 pedicle diameter was 5.3 mm (±2.0 mm). This was smaller than Western population pedicle diameters. The average length of the both pedicles to the midpoint of the C2 vertebral body was 23.5 mm (±3.3 mm on the left and ±2.3 mm on the right). Conclusions: The results of this first study in the South East Asian population should help guide and improve the safety in occipito-cervical region instrumentation. Thus reducing the risk of technical failures and neuro-vascular injury.