Effects of HAT-CN Layer Thickness on Molecular Orientation and Energy-Level Alignment with ZnPc.

Efficient energy-level alignment is crucial for achieving high performance in organic electronic devices. Because the electronic structure of an organic semiconductor is significantly influenced by its molecular orientation, comprehensively understanding the molecular orientation and electronic structure of the organic layer is essential. In this study, we investigated the interface between a 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) hole injection layer and a zinc-phthalocyanine (ZnPc) p-type organic semiconductor. To determine the energy-level alignment and molecular orientation, we conducted in situ ultraviolet and X-ray photoelectron spectroscopies, as well as angle-resolved X-ray absorption spectroscopy. We found that the HAT-CN molecules were oriented relatively face-on (40°) in the thin (5 nm) layer, whereas they were oriented relatively edge-on (62°) in the thick (100 nm) layer. By contrast, ZnPc orientation was not significantly altered by the underlying HAT-CN orientation. The highest occupied molecular orbital (HOMO) level of ZnPc was closer to the Fermi level on the 100 nm thick HAT-CN layer than on the 5 nm thick HAT-CN layer because of the higher work function. Consequently, a considerably low energy gap between the lowest unoccupied molecular orbital level of HAT-CN and the HOMO level of ZnPc was formed in the 100 nm thick HAT-CN case. This may improve the hole injection ability of the anode system, which can be utilized in various electronic devices.

Extent of Contrast Enhancement on Non-Enhanced Computed Tomography after Intra-Arterial Thrombectomy for Acute Infarction on Anterior Circulation: As a Predictive Value for Malignant Brain Edema.

OBJECTIVE: To determine whether the use of contrast enhancement (especially its extent) predicts malignant brain edema after intra-arterial thrombectomy (IAT) in patients with acute ischemic stroke. METHODS: We reviewed the records of patients with acute ischemic stroke who underwent IAT for occlusion of the internal carotid artery or the middle cerebral artery between January 2012 and March 2015. To estimate the extent of contrast enhancement (CE), we used the contrast enhancement area ratio (CEAR)-i.e., the ratio of the CE to the area of the hemisphere, as noted on immediate non-enhanced brain computed tomography (NECT) post-IAT. Patients were categorized into two groups based on the CEAR values being either greater than or less than 0.2. RESULTS: A total of 39 patients were included. Contrast enhancement was found in 26 patients (66.7%). In this subgroup, the CEAR was greater than 0.2 in 7 patients (18%) and less than 0.2 in the other 19 patients (48.7%). On univariate analysis, both CEAR ≥0.2 and the presence of subarachnoid hemorrhage were significantly associated with progression to malignant brain edema (p<0.001 and p=0.004), but on multivariate analysis, only CEAR ≥0.2 showed a statistically significant association (p=0.019). In the group with CEAR ≥0.2, the time to malignant brain edema was shorter (p=0.039) than in the group with CEAR <0.2. Clinical functional outcomes, based on the modified Rankin scale, were also significantly worse in patients with CEAR ≥0.2 (p=0.003). CONCLUSION: The extent of contrast enhancement as noted on NECT scans obtained immediately after IAT could be predictive of malignant brain edema and a poor clinical outcome.

Post-Traumatic Arteriovenous Fistula of the Scalp.

Arteriovenous fistula of the scalp is relatively rare disease. We report a traumatic arteriovenous fistula of the scalp treated with complete surgical excision and review the literature with regard to etiology, pathogenesis, and management of these unusual lesions.

Three Cases of Calcifying Pseudoneoplasm which Involve the Epidural Space of the Spine.

Calcifying psuedoneoplasm of the spine is a rare non-neoplastic lesion of unknown origin. Radiologic and histologic manifestations are very variable and clinical symptoms include isolated pain, myelopathy, and radiculopathy. Surgical resection is the preferred option of treatment. This report describes three cases of calcifying pseudoneoplasm in the spine. The first case is a 77-year-old female with pain in both legs. The second case is a 67-year-old woman who presented as right leg pain. The third case is a 78-year-old woman with isolated back pain. The involved sites of each of cases were T12, L2-3, and L1, respectively. Surgical resection of the involved masses relieved symptoms.

The efficacy and perioperative complications associated with lumbar spinal fusion surgery, focusing on geriatric patients in the republic of Korea.

OBJECTIVE: The purpose of this study was to examine the efficacy and perioperative complications associated with lumbar spinal fusion surgery, focusing on geriatric patients in the Republic of Korea. METHODS: We retrospectively investigated 485 patients with degenerative spinal diseases who had lumbar spinal fusion surgeries between March 2006 and December 2010 at our institution. Age, sex, comorbidity, American Society of Anesthesiologists (ASA) class, fusion segments, perioperative complications, and outcomes were analyzed in this study. Risk factors for complications and their association with age were analyzed. RESULTS: In this study, 81 patients presented complications (16.7%). The rate of perioperative complications was significantly higher in patients 70 years or older than in other age groups (univariate analysis, p=0.015; multivariate analysis, p=0.024). The perioperative complications were not significantly associated with the other factors tested (sex, comorbidity, ASA class, and fusion segments). Post-operative outcomes of lumbar spinal fusion surgeries for the patients were determined on the basis of MacNab's criteria (average follow up period : 19.7 months), and 412 patients (85.0%) were classified as having "excellent" or "good" results. CONCLUSION: Increasing age was an important risk factor for perioperative complications in patients undergoing lumbar spinal fusion surgery, whereas other factors were not significant. However, patients' satisfaction or return to daily activities when compared with younger patients did not show much difference. We recommend good clinical judgment as well as careful selection of geriatric patients for lumbar spinal fusion surgery.

Giant cystic cerebral cavernous malformation with multiple calcification - case report.

Cerebral cavernous malformation with giant cysts is rare and literature descriptions of its clinical features are few. In this case study, the authors describe the clinical symptoms, radiological findings, and pathological diagnosis of cerebral cavernous malformations with giant cysts, reviewing the relevant literature to clearly differentiate this from other disease entities. The authors present a case of a 19-year-old male with a giant cystic cavernous malformation, who was referred to the division of neurosurgery due to right sided motor weakness (grade II/II). Imaging revealed a large homogenous cystic mass, 7.2×4.6×6 cm in size, in the left fronto-parietal lobe and basal ganglia. The mass had an intra-cystic lesion, abutting the basal portion of the mass. The initial diagnosis considered this mass a glioma or infection. A left frontal craniotomy was performed, followed by a transcortical approach to resect the mass. Total removal was accomplished without post-operative complications. An open biopsy and a histopathological exam diagnosed the mass as a giant cystic cavernous malformation. Imaging appearances of giant cavernous malformations may vary. The clinical features, radiological features, and management of giant cavernous malformations are described based on pertinent literature review.

The role of hyperthyroidism as the predisposing factor for superior sagittal sinus thrombosis.

Superior sagittal sinus thrombosis (SSST) is an uncommon cause of stroke, whose symptoms and clinical course are highly variable. It is frequently associated with a variety of hypercoagulable states. Coagulation abnormalities are commonly seen in patients with hyperthyroidism. To the best of our knowledge, there are few reports on the association between hyperthyroidism and cerebral venous thrombosis. We report on a 31-year-old male patient with a six-year history of hyperthyroidism who developed seizure and mental deterioration. Findings on brain computed tomography (CT) showed multiple hemorrhages in the subcortical area of both middle frontal gyrus and cerebral digital subtraction angiography (DSA) showed irregular intra-luminal filling defects of the superior sagittal sinus. These findings were consistent with hemorrhagic transformation of SSST. Findings on clinical laboratory tests were consistent with hyperthyroidism. In addition, our patient also showed high activity of factors IX and XI. The patient received treatment with oral anticoagulant and prophylthiouracil. His symptoms showed complete improvement. A follow-up cerebral angiography four weeks after treatment showed a recanalization of the SSS. In conclusion, findings of our case indicate that hypercoagulability may contribute to development of SSST in a patient with hyperthyroidism.

Comparison of posterior fixation alone and supplementation with posterolateral fusion in thoracolumbar burst fractures.

OBJECTIVE: We compared the radiological and clinical outcomes between patients who underwent posterior fixation alone and supplemented with fusion following the onset of thoracolumbar burst fractures. In addition, we also evaluated the necessity of posterolateral fusion for patients treated with posterior pedicle screw fixation. METHODS: From January 2007 to December 2009, 46 consecutive patients with thoracolumbar burst fracture were included in this study. On the basis of posterolateral fusion, we divided our patients into the non-fusion group and the fusion group. The radiological assessment was performed according to the Cobb's method, and results were obtained at immediately, 3, 6, 12 months after surgery. The clinical outcomes were evaluated using the modified Mcnab criteria at the final follow-up. RESULTS: The demographic data and the mean follow-up period were similar between the two groups. Patients of both groups achieved satisfactory clinical outcomes. The mean loss of kyphosis correction showed that patients of both groups experienced loss of correction with no respect to whether they underwent the posterolateral fusion. There was no significant difference in the degree of loss of correction at any time points of the follow-up between the two groups. In addition, we also compared the effect of fixed levels (i.e., short versus long segment) on loss of correction between the two groups and there was no significant difference. There were no major complications postoperatively and during follow-up period. CONCLUSION: We suggest that posterolateral fusion may be unnecessary for patients with thoracolumbar burst fractures who underwent posterior pedicle screw fixation.

Comparative Study of Posterior Lumbar Interbody Fusion via Unilateral and Bilateral Approaches in Patients with Unilateral Leg Symptoms.

OBJECTIVE: We investigated the clinical and radiological advantages of unilateral laminectomy in posterior lumbar interbody fusion (PLIF) procedure comparing with bilateral laminectomy, under the same procedural condition including bilateral instrumentation and insertion of two cages, in patients with degenerative lumbar disease with unilateral leg symptoms. METHODS: We retrospectively reviewed 124 consecutive cases of PLIF via unilateral or bilateral approach between January 2006 and April 2010. In 80 cases (bilateral group), two cages were inserted via bilateral laminectomy, and in 44 cases (unilateral group), via unilateral laminectomy. The average follow-up duration was 29.5 months. The clinical outcomes were evaluated with the Visual Analogue Scale (VAS) and the Oswestry disability index (ODI). The fusion rates and disc space heights were determined by dynamic standing radiographs and/or computed tomography. Operative times, intra-operative and post-operative blood losses and hospitalization periods were also evaluated. RESULTS: In clinical evaluation, the VAS and ODI scores showed excellent outcomes in both groups. There were no significant differences in term of fusion rate, but the perioperative blood loss and the operative time of the unilateral group were lower than that of the bilateral group. CONCLUSION: Unilateral laminectomy can minimize the operative time and perioperative blood loss in PLIF procedure. However, the different preoperative disc height between two groups is a limitation of this study. Despite this limitation, solid fusion and satisfactory symptomatic improvement could be achieved uniquely by our surgical method. This surgical method can be an alternative surgical technique in patients with unilateral leg pain.

Time to recover consciousness in patients with diffuse axonal injury : assessment with reference to magnetic resonance grading.

OBJECTIVE: This study was conducted to investigate the correlation between the degrees of injury on brain magnetic resonance imaging (MRI) and the time interval to recovery of consciousness in patients with diffuse axonal injury. METHODS: From January 2004 to December 2008, 25 patients with diffuse axonal injury were treated at our hospital. We retrospectively investigated the patients' medical records and radiological findings. We divided the patients into three groups according to the grade of MRI finding : grade I, small scattered lesions on the white matter of the cerebral hemisphere; grade II, focal lesions on the corpus callosum; and grade III, additional focal lesions on the brain stem. RESULT: Seven patients belonged to the grade I group; 10 to the grade II group; and 8 to the grade III group. The mean Glasgow Coma Scale (GCS) score of all patients at the time of admission was 7.28. Recovery of consciousness was observed in 23 of the 25 patients; the remaining two patients never regained consciousness. The time interval to recovery of consciousness (awake status) ranged from 1 day to 125 days (mean 22.1 days) : grade I group patients, within approximately 1 week (mean 3.7 days); grade II group patients, within approximately 2 weeks (mean 12.5 days); and grade III group patients, within approximately 2 months (mean 59.5 days). CONCLUSION: Our study results suggest a correlation between the mean time interval to recovery of consciousness in patients with diffuse axonal injuries and the degrees of brain injuries seen on MRI. Patients with grade I and II diffuse axonal injuries recovered consciousness within 2 weeks, while patients with grade III injuries required approximately 2 months.

Spontaneous spinal epidural hematoma.

Spontaneous spinal epidural hematoma (SSEH) is a relatively rare but significant spinal condition. Urgent surgical evacuation of a hematoma is generally indicated to prevent serious permanent neurological deficits. We encountered three cases of spontaneous spinal epidural hematomas associated with motor weakness that were treated successfully by surgical intervention.

Brucellar spondylitis.

The incidence of Brucellosis is increasing in Korea. Spondylitis is the most frequent complication, but it is difficult to diagnose because its clinical symptoms are non-specific. It should therefore be included in the differential diagnosis of back pain. We report three rare cases of brucellar spondylitis successfully treated by medical and surgical therapy.

Extraordinarily long-term posttraumatic cerebrospinal fluid fistula.

Most posttraumatic cerebrospinal fluid (CSF) leakage is noticed by the patients with the first symptom, rhinorrhea. A 38-year-old woman presented with frequent clear continuous rhinorrhea and otorrhea for 5 years after basilar skull fracture. After this, meningitis was developed with subsequent CSF fistula. Her clinical symptom was improved by medical treatment. The dural defect and CSF leakage were not detected by computerized tomography (CT) cisternography. We report a rare case of persistent posttraumatic CSF fistula that continued for five years.

Aneurysms located at the proximal anterior cerebral artery and anterior communicating artery associated with middle cerebral artery aplasia: case report.

BACKGROUND: Aneurysms arising from the proximal anterior cerebral artery (ACA) are quite rare. Here, we report upon such a case of aneurysms located at the proximal ACA and anterior communicating artery associated with middle cerebral artery (MCA) aplasia. CASE DESCRIPTION: A 64-year-old woman complained of severe headache. Brain computed tomography scans demonstrated acute subarachnoid hemorrhage. Angiograms showed 2 aneurysms located at the anterior communicating artery and proximal ACA, but did not show an MCA shadow on the lesion side. Instead, multiple collateral vessels ran toward the sylvian fissure and supplied the MCA territory, together with hypertrophied perforating branches. The operative findings confirmed that the cordlike rudimentary MCA had no internal blood flow. The 2 aneurysms were secured by neck clipping. CONCLUSION: The combined effects of these anomalies on the hemodynamic equilibrium of the arteries and the genesis of the aneurysms are noteworthy.

Spinal subdural hematoma following craniotomy: case report.

BACKGROUND: Spinal subdural hematomas (SSH) are a rare cause of spinal cord compression. SSH following clipping of an aneurysm has only been reported once. We now report such a case and discuss the mechanism of SSH development after aneurysmal neck clipping. CASE DESCRIPTION: A 32-year-old man complained of lumbago 7 days after craniotomy for the clipping of an aneurysm. Neurologic examination revealed no abnormality, but magnetic resonance imaging (MRI) demonstrated a lumbosacral spinal subdural hematoma. He received conservative management and his lumbago showed improvement. An MRI taken 19 days after surgery revealed a residual hematoma. CONCLUSION: The downward movement of blood from the cranial subdural compartment under the influence of gravity is the most appropriate explanation for SSH following craniotomy.