Hsu-Huei Weng

Factors affecting graft infection after cranioplasty.

The aim of this study was to identify the risk factors associated with bone grafts infection after cranioplasty. Eighty-four cranioplasties were performed on 75 patients between 2002 and 2006. Cryopreserved bone grafts were used as graft material in group 1 and polymethylmethacrylate (PMMA) was used in group 2. Risk factors including age, gender, time intervals between craniectomy and cranioplasty, mechanism of injury, number of procedures, graft material, and the Glasgow Coma Scale score were compared between groups. Swab culture results and bone graft infection were assessed in group 1. Multiple procedures before cranioplasty and an inadequate time interval between craniectomy and cranioplasty increase the risk of infection after cranioplasty. Swab culture results, age, gender, mechanism of injury, graft material and Glasgow Coma Scale score are not related to infection. The use of PMMA was associated with a relatively low risk of infection (6.25%). Risk of graft infection was not associated with the choice of graft material in the present study. Multiple procedures and insufficient time intervals increase the risk of infection. Interrupting the wound healing process may be the cause of infection. PMMA is a safe material for cranioplasty regardless of previous infection.

Embolization of a ruptured lenticulostriate artery aneurysm.

Aneurysms arising from the lenticulostriate artery (LSA) are rare. So far, only 23 cases have been reported in the literature (Ahn et al. 2007 [1], Gandhi et al. 2008 [2], Harreld et al. 2010 [3]). Early detection and treatment of these aneurysms is difficult because of their small size, deep location and complex surrounding vasculature. The majority of reported cases were treated surgically, and only two were treated with endovascular embolization (Harreld et al. 2010 [3], Larrazabal et al. 2001 [4]). We present here a case of an LSA aneurysm that was successfully embolized with n-butyl cyanoacrylate (n-BCA) with no recurrence after 1 year of follow-up.

Hydrocephalus following decompressive craniectomy for malignant middle cerebral artery infarction

OBJECTIVE The aim of this study was to evaluate the incidence of hydrocephalus and understand the influence of hydrocephalus on the functional outcome of patients undergoing decompressive craniectomy for malignant middle cerebral artery (MCA) infarction. METHODS We retrospectively analyzed data of consecutive patients who underwent decompressive craniectomy for malignant MCA infarction. Clinical and imaging data were reviewed to confirm the incidence of hydrocephalus and evaluate the impact of hydrocephalus on functional outcome. The functional outcomes of patients were estimated with the Glasgow outcome score at 1year after stroke onset. RESULTS Seventeen patients who received decompressive craniectomy for malignant MCA infarction from January 2003 to December 2006 were enrolled. Persistent hydrocephalus developed in 5 patients. The functional outcomes in these patients were uniformly poor regardless of cerebrospinal fluid diversion surgery. Our data revealed that functional outcome was related to patient age and the duration from infarction to craniectomy. CONCLUSIONS Persistent hydrocephalus is common in patients who receive decompressive craniectomy for malignant MCA infarction. However, the shunt procedure does not significantly improve the patients clinical condition. The timing of operation in relation to the functional outcome may be critical.

Gastrointestinal Hemorrhage after Acute Ischemic Stroke and Its Risk Factors in Asians

Background: The aim of this study was to examine the frequency and risk factors of gastrointestinal (GI) hemorrhage in acute ischemic stroke patients in Taiwan. Method: 920 patients admitted for acute ischemic stroke from January 2001 to October 2005 were included in the study. We reviewed the available medical records for any episode of GI hemorrhage, possible precipitating factors and administration of ulcer prophylaxis. Results: Seventy-two patients (7.8%) experienced GI hemorrhage; these patients were of an older age (74.7 vs. 69.0 years, p < 0.001), had a longer acute ward stay (30.4 vs. 12.9 days, p < 0.001) and higher mortality rate (odds ratio 9.61, CI 4.53–20.42) than patients without GI hemorrhage. In multivariate logistic regression analysis, the important risk factors of GI hemorrhage included sepsis, previous history of GI hemorrhage, severe stroke, renal insufficiency and abnormal liver function. Of the 779 patients who had a 0–1 risk factor, 26 (3.3%) experienced GI hemorrhage; of the 27 patients with more than 2 risk factors, 17 (63%) suffered GI hemorrhage. Conclusion: This study of Asians revealed a higher frequency of GI hemorrhage after acute ischemic stroke than that reported in previous studies, and the frequency of GI hemorrhage was positively correlated with the number of risk factors present. We suggest that identifying stroke patients with a high risk of hemorrhage may allow clinicians to set up ulcer prophylactic protocols for the patients most likely to benefit, especially in an Asian population.

Fate of Diffusion Restricted Lesions in Acute Intracerebral Hemorrhage

Background Diffusion-restricted lesions on diffusion-weighted imaging (DWI) are detected in patients with intracerebral hemorrhage (ICH). In this study, we aimed to determine the fate of DWI lesions in ICH patients and whether the presence of DWI lesions is associated with functional outcome in patients with ICH. Methods This prospective study enrolled 153 patients with acute ICH. Baseline MRI scans were performed within 2 weeks after ICH to detect DWI lesions and imaging markers for small vessel disease (SVD). Follow-up MRI scans were performed at 3 months after ICH to assess the fate of the DWI lesions. We analyzed the associations between the characteristics of DWI lesions with clinical features and functional outcome. Results Seventeen of the 153 patients (11.1%) had a total of 25 DWI lesions. Factors associated with DWI lesions were high initial systolic and mean arterial blood pressure (MAP) at the emergency room, additional lowering of MAP within 24 hours, and the presence of white matter hyperintensity and cerebral microbleeds. Thirteen of the 25 DWI lesions (52%) were not visible on follow-up T2-weighted or fluid-attenuated inversion recovery images and were associated with high apparent diffusion coefficient value and a sharper decease in MAP. The regression of DWI lesions was associated with good functional outcome. Conclusions More than half of the DWI lesions in the ICH patients did not transition to visible, long-term infarction. Only if the DWI lesion finally transitioned to final infarction was a poor functional outcome predicted. A DWI lesion may be regarded as an ischemic change of SVD and does not always indicate certain cerebral infarction or permanent tissue injury.

Effect of dehydration on the development of collaterals in acute middle cerebral artery occlusion.

Recent large series studies have demonstrated that dehydration is common amongst stroke subjects and is associated with poor outcome. However, the effects of hydration status on the development of collaterals have never been discussed. In this study, the hypothesis that hydration status is an important factor for developing collaterals after acute middle cerebral artery (MCA) infarction was tested.

Motor function improvement in patients undergoing surgery for spinal epidural abscess.

BACKGROUNDSpinal epidural abscess (SEA) is a rare and devastating clinical entity. Definitive diagnosis is usually delayed because most patients present initially with minor or variable symptoms resulting in poor outcome. The clinical outcome of SEA has been associated with various prognostic factors; however, reports on factors relating to motor function improvement after surgical treatment are limited. OBJECTIVEThe aim of this study is to elucidate which clinical factors may affect motor function recovery after surgical treatment of SEA. PATIENT AND METHODSThe clinical features of patients with SEA undergoing surgical drainage and antibiotics treatment were reviewed, and their outcomes were identified and analyzed. RESULTSThe most common presenting symptoms were neck or back pain, motor deficits, and urinary incontinence. The most common underlying medical condition was diabetes mellitus. Leukocytosis (P = .036; odds ratio [OR] = 0.754; confidence interval [CI] = 0.579–0.982), elevated C-reactive protein level (P = .017; OR 0.96; CI = 0.965–0.994), poor glycemic control (P = .012; OR = 23.33; CI = 1.992–273.29), and duration of motor deficit at the time of operation (P = .005; OR = 40.50; CI = 3.093–530.293) were found to have a strong influence on motor function improvement after surgical treatment. CONCLUSIONInfection control and the prevention of further neurological deterioration in time are paramount in the treatment of SEA for optimal recovery. Patients with rapid neurological deterioration or higher white blood cell count or C-reactive protein level on presentation warrant aggressive surgical intervention; even in those who are completely paralyzed, an improvement in muscle power may still be possible.

Hemodynamic Factors May Play a Critical Role in Neurological Deterioration Occurring within 72 hrs after Lacunar Stroke

Background Whether a perfusion defect exists in lacunar infarct and whether it is related to early neurological deterioration (END) is still under debate. The aim of this study was to evaluate whether END in lacunar infarct is related to a perfusion defect using diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI) and perfusion MR imaging. Methods One hundred and forty-one consecutive patients had an MRI scan within 30 hours after onset of symptoms and 43 patients with acute lacunar infarct and classic lacunar syndrome were recruited. The MRI sequences included DWI, DTI and cerebral blood flow (CBF) maps to respectively represent the topographic locations of acute infarcts, the corticospinal tract and perfusion defects. The END was defined in reference to the National Institute of Health Stroke Scale (NIHSS) as an increase ≧2 within 72 hours. Cohens Kappa coefficient was used to examine the reliability between the 2 image readers. A multivariate logistic regression model was constructed adjusting for baseline variables. Results Ten out of the 43 patients had END. Patients having END was significantly associated with lower chances of favorable and good outcomes at 3 months (p = 0.01 and p = 0.002, respectively). END was predicted when the non-core hypoperfused area overlapped on the corticospinal tract, which is defined as the expected END profile. Cohens Kappa coefficient between the 2 image readers to define images of expected END profiles was 0.74. In 15 patients with expected END profile, 9 had END clinically, whereas 28 patients had no expected END profile, and only 1 patient had END (p<0.0001). After adjusting for sex, the expected END profile was still associated with END (odds ratio, 42.2; p = 0.002). Conclusion Our study demonstrated that the END in acute lacunar stroke is likely related to the transformation of non-core hypoperfused area into infarction in the anatomy of corticospinal tracts.

Altered Resting-State fMRI Signals in Acute Stroke Patients with Ischemic Penumbra

Background Identifying the ischemic penumbra in acute stroke subjects is important for the clinical decision making process. The aim of this study was to use resting-state functional magnetic resonance singal (fMRI) to investigate the change in the amplitude of low-frequency fluctuations (ALFF) of these subjects in three different subsections of acute stroke regions: the infarct core tissue, the penumbra tissue, and the normal brain tissue. Another aim of this study was to test the feasilbility of consistently detecting the penumbra region of the brain through ALFF analysis. Methods Sixteen subjects with first-ever acute ischemic stroke were scanned within 27 hours of the onset of stroke using magnetic resonance imaging. The core of infarct regions and penumbra regions were determined by diffusion and perfusion-weighted imaging respectively. The ALFF were measured from resting-state blood oxygen level dependent (BOLD) fMRI scans. The averaged relative ALFF value of each regions were correlated with the time after the onset of stroke. Results Relative ALFF values were significantly different in the infarct core tissue, penumbra tissue and normal brain tissue. The locations of lesions in the ALFF maps did not match perfectly with diffusion and perfusion-weighted imagings; however, these maps provide a contrast that can be used to differentiate between penumbra brain tissue and normal brain tissue. Significant correlations between time after stroke onset and the relative ALFF values were present in the penumbra tissue but not in the infarct core and normal brain tissue. Conclusion Preliminary results from this study suggest that the ALFF reflects the underlying neurovascular activity and has a great potential to estimate the brain tissue viability after ischemia. Results also show that the ALFF may contribute to acute stroke imaging for thrombolytic or neuroprotective therapies.

Voxel-based analysis of apparent diffusion coefficient in perihaematomal oedema: associated factors and outcome predictive value for intracerebral haemorrhage

Objectives The pathophysiology of perihaematomal oedema (PO) surrounding a primary intracerebral haemorrhage (ICH) is complicated and incompletely understood. We prospectively investigated the components of PO with voxel-based analysis of the apparent diffusion coefficient (ADC) value and assessed its predictive value for functional outcome. Design Forty-six patients with ICH who were enrolled for clinical evaluation underwent MRI scans within 24 h after ICH. Based on the ADC value of the ipsilateral voxels divided by the mean ADC value of the contralateral mirror region of interest, the voxels with oedema were classified into three categories: cytotoxic, vasogenic and undetermined. The percentages of cytotoxic and vasogenic oedema were then calculated and correlated with clinical outcome according to the modified Rankin Scale (mRS) at 6 months after ICH. The intraobserver and interobserver reliability of this method were examined using intraclass correlation coefficients. Results The intraclass correlation coefficients showed that analysis using the voxel-based method is highly reliable. Among the clinical variables tested, age and serum creatinine levels were positively correlated with percentage of cytotoxic oedema. Age, history of coronary artery disease, National Institutes of Health Stroke Scale score and percentage of cytotoxic oedema were all associated with mRS at 6 months after ICH. Conclusions The pathophysiological processes within PO are complicated. Voxel-based analysis of ADC values may help to identify the components of PO and may be beneficial for decision making and predicting outcome.