Predictive Factors of First-Pass Effect in Patients Who Underwent Successful Endovascular Thrombectomy for Emergent Large Vessel Occlusion

OBJECTIVE

The primary treatment goal of current endovascular thrombectomy (EVT) for emergent large-vessel occlusion (ELVO) is complete recanalization after a single maneuver, referred to as the 'first-pass effect' (FPE). Hence, we aimed to identify the predictive factors of FPE and assess its effect on clinical outcomes in patients with ELVO of the anterior circulation.

METHODS

Among the 129 patients who participated, 110 eligible patients with proximal ELVO (intracranial internal carotid artery and proximal middle cerebral artery) who achieved successful recanalization after EVT were retrospectively reviewed. A comparative analysis between patients who achieved FPE and all others (defined as a non-FPE group) was performed regarding baseline characteristics, clinical variables, and clinical outcomes. Multivariate logistic regression analyses were subsequently conducted for potential predictive factors with p<0.10 in the univariate analysis to determine the independent predictive factors of FPE.

RESULTS

FPE was achieved in 31 of the 110 patients (28.2%). The FPE group had a significantly higher level of functional independence at 90 days than did the non-FPE group (80.6% vs. 50.6%, p=0.002). Pretreatment intravenous thrombolysis (IVT) (odds ratio [OR], 3.179; 95% confidence interval [CI], 1.025-9.861; p=0.045), door-to-puncture (DTP) interval (OR, 0.959; 95% CI, 0.932-0.987; p=0.004), and the use of balloon guiding catheter (BGC) (OR, 3.591; 95% CI, 1.231-10.469; p=0.019) were independent predictive factors of FPE.

CONCLUSION

In conclusion, pretreatment IVT, use of BGC, and a shorter DTP interval were positively associated with FPE, increasing the chance of acquiring better clinical outcomes.

Distal placement of balloon guide catheter facilitates stent-retriever mechanical thrombectomy for acute ischemic stroke in the anterior circulation

PURPOSE

Although balloon guide catheters (BGCs) have been demonstrated to improve recanalization and functional outcomes by enabling proximal flow control and forced aspiration during mechanical thrombectomy (MT), the significance of the BGC location has been overlooked. We evaluated the impact of BGC location during MT for anterior circulation acute ischemic stroke (AIS).

METHODS

Patients were divided into the proximal and distal BGC groups according to the BGC tip location relative to the lower margin of the C1 vertebral body. Endovascular and clinical outcomes were compared between the two groups, including subgroup analyses of the two types of extracranial internal carotid artery (ICA) anatomy, categorized based on cerebral angiography.

RESULTS

A total of 124 patients were analyzed, with 62 each in the proximal and distal BGC placement groups. The distal BGC group had higher rates of first-pass recanalization (FPR) (38.7% vs. 17.7%, P = 0.009) and favorable outcomes (64.5% vs. 46.8%, P = 0.047) with shorter procedure time (47.5 min vs. 65 min, P = 0.001) and fewer distal embolization (3.2% vs. 12.9%, P = 0.048) than the proximal BGC group. FPR was also more frequently achieved in the distal BGC group of patients with tortuous ICA (37.0% vs. 12.5%, P = 0.029). Multivariate analysis showed that distal BGC placement was an independent predictor of FPR (odds ratio, 3.092; 95% confidence interval, 1.326-7.210; P = 0.009).

CONCLUSION

Distal BGC placement facilitates MT for AIS in the anterior circulation. Therefore, we suggest distal BGC placement to maximize the effect of thrombectomy, even for tortuous extracranial ICA.

Factors predicting good prognosis of failed intra-arterial thrombectomy cases: A retrospective study

Intra-arterial thrombectomy (IAT) has been increasingly applied in the treatment of acute ischemic stroke (AIS) due to large-vessel occlusion, and many related studies have been published. However, limited studies on the prognosis of failed-IAT patients are available. In this study, factors that can predict a good prognosis in patients with failed IAT were studied. Among patients who visited our hospital between January 2016 and September 2022 and underwent IAT, we retrospectively analyzed those with failed IAT. A univariate analysis was performed on the radiological features, medical histories, and other patient characteristics expected to affect the prognosis, and a multivariate analysis was performed on some of these factors. In univariate analysis, a good collateral channel on susceptibility-weighted imaging (SWI), modified thrombolysis in cerebral infarction (mTICI) 2A recanalization, and the pre-procedural modified Rankin scale (mRS) were statistically significant. In the multivariate analysis, good collateral channels on SWI and computed tomography angiography (CTA) and mTICI 2A recanalization were statistically significant. Factors that can predict a good prognosis in patients with failed IAT include good leptomeningeal collateral channels evaluated by CTA and SWI and mTICI 2A recanalization.

Outcomes Following Carotid Endarterectomy and Carotid Artery Stenting in Patients with Carotid Artery Stenosis: A Retrospective Study from a Single Center in South Korea

BACKGROUND Previous randomized controlled trials and meta-analyses comparing carotid endarterectomy (CEA) and carotid artery stenting (CAS) included a large number of patients, but the diagnosis, treatment selection, and performance were heterogeneous. This retrospective study from a single center in South Korea aimed to evaluate outcomes following CEA and CAS in patients with carotid artery stenosis. MATERIAL AND METHODS A retrospective analysis was performed using the data of patients who underwent carotid revascularization between September 2016 and June 2021 at a single institution. The primary outcomes were stroke, myocardial infarction (MI), and death during the periprocedural period. RESULTS We enrolled a total of 61 (44 symptomatic and 17 asymptomatic) patients who underwent CEA or CAS. Among them, 36 (59%) underwent CEA and 25 (41%) underwent CAS. Statistically significant differences were found between the groups in degree of carotid stenosis (CEA: 87.0±9.1, CAS: 80.5±9.3, P=0.007). All patients with confirmed plaque ulceration before carotid revascularization underwent CEA. Two (3.3%) periprocedural strokes occurred, 1 in each group, on the ipsilateral side. There were no significant differences between CEA and CAS in the event-free survival rate for stroke during the follow-up (log-rank test=0.806). CONCLUSIONS Favorable outcomes in terms of periprocedural stroke were observed. We found no significant difference between the 2 carotid revascularization techniques in the incidence of periprocedural stroke in symptomatic and asymptomatic patients. To confirm our findings, further studies involving a larger number of patients and continuous follow-up are necessary.

Predictors of intracranial hemorrhage after mechanical thrombectomy using a stent-retriever for anterior circulation ischemic stroke: A retrospective study

Intracranial hemorrhage (ICH) after mechanical thrombectomy (MT) is a potentially catastrophic complication. We aimed to identify predictors of hemorrhagic complications following MT using a stent-retriever (SR) for acute ischemic stroke (AIS) patients due to large vessel occlusion of anterior circulation. In consecutive AIS patients, the clinical and procedural variables were retrospectively analyzed. ICH was evaluated on computed tomography performed 24 hours following MT and dichotomized into asymptomatic ICH and symptomatic intracranial hemorrhage (SICH) depending on the presence of neurological deterioration. Using univariate and multivariate analyses, the predictors of ICH and SICH were identified. The optimal cutoff value for predicting SICH was determined by receiver operating characteristic (ROC) analysis. Among 135 patients, ICH was detected in 52 (38.5%), and 17 (12.6%) were classified as having SICH. We found that serum glucose level (odds ratio [OR] 1.016, P = .011) and number of SR passes (OR 2.607, P < .001) were significantly correlated with ICH. Independent predictors of SICH included the baseline Alberta stroke program early computed tomography score (ASPECTS) (OR 0.485, P = .042), time from stroke onset to groin puncture (OTP) (OR 1.033, P = .016), and number of SR passes (OR 2.342, P = .038). In ROC analysis, baseline ASPECTS ≤ 7, OTP > 280 minutes, and SR passes > 3 were the optimal cutoff values for predicting SICH. In conclusion, serum glucose level and SR pass serve as predictors for any form of ICH in large vessel occlusion-induced AIS patients undergoing MT. Moreover, patients with lower ASPECTS, prolonged OTP, and multiple SR passes are more vulnerable to SICH.

Predictive Factors of Surgical Site Infection Following Cranioplasty: A Study Including 3D Printed Implants

In patients who have undergone decompressive craniectomy (DC), subsequent cranioplasty is required to reconstruct cranial defects. Surgical site infection (SSI) following cranioplasty is a devastating complication that can lead to cranioplasty failure. The aim of the present study, therefore, was to identify predictive factors for SSI following cranioplasty by reviewing procedures performed over a 10-year period. A retrospective analysis was performed for all patients who underwent cranioplasty following DC between 2010 and 2020 at a single institution. The patients were divided into two groups, non-SSI and SSI, in order to identify clinical variables that are significantly correlated with SSI following cranioplasty. Cox proportional hazards regression analyses were then performed to identify predictive factors associated with SSI following cranioplasty. A total of 172 patients who underwent cranioplasty, including 48 who received customized three-dimensional (3D) printed implants, were enrolled in the present study. SSI occurred in 17 patients (9.9%). Statistically significant differences were detected between the non-SSI and SSI groups with respect to presence of fluid collections on CT scans before and after cranioplasty. Presence of fluid collections on computed tomography (CT) scan before (p = 0.0114) and after cranioplasty (p < 0.0000) showed significant association with event-free survival rate for SSI. In a univariate analysis, significant predictors for SSI were fluid collection before (p = 0.0172) and after (p < 0.0001) cranioplasty. In a multivariate analysis, only the presence of fluid collection after cranioplasty was significantly associated with the occurrence of SSI (p < 0.0001). The present study investigated predictive factors that may help identify patients at risk of SSI following cranioplasty and provide guidelines associated with the procedure. Based on the results of the present study, only the presence of fluid collection on CT scan after cranioplasty was significantly associated with the occurrence of SSI. Further investigation with long-term follow-up and large-scale prospective studies are needed to confirm our conclusions.

Gender differences in adult traumatic brain injury according to the Glasgow coma scale: A multicenter descriptive study

PURPOSE

Patients' gender, which can be one of the most important determinants of traumatic brain injury (TBI) outcomes, is also likely to interact with many other outcome variables of TBI. This multicenter descriptive study investigated gender differences in epidemiological, clinical, treatment, mortality, and variable characteristics in adult TBI patients.

METHODS

The selection criteria were defined as patients who had been diagnosed with TBI and were admitted to the hospital between January 1, 2016 and December 31, 2018. A total of 4468 adult TBI patients were enrolled at eight University Hospitals. Based on the list of enrolled patients, the medical records of the patients were reviewed and they were registered online at each hospital. The registered patients were classified into three groups according to the Glasgow coma scale (GCS) score: mild (13-15), moderate (9-12), and severe (3-8), and the differences between men and women in each group were investigated. The risk factors of moderated and severe TBI compared to mild TBI were also investigated.

RESULTS

The study included 3075 men and 1393 women and the proportion of total males was 68.8%. Among all the TBI patients, there were significant differences between men and women in age, past history, and GCS score. While the mild and severe TBI groups showed significant differences in age, past history, and clinical symptoms, the moderate TBI group showed significant differences in age, past history, cause of justice, and diagnosis.

CONCLUSION

To the best of our knowledge, this multicenter study is the first to focus on gender differences of adult patients with TBI in Korea. This study shows significant differences between men and women in many aspects of adult TBI. Therefore, gender differences should be strongly considered in TBI studies.

Paraspinal muscle changes after single-level posterior lumbar fusion: volumetric analyses and literature review

Background

Posterior lumbar fusion is a widely accepted surgical technique; however, it has been related to the possibility of paraspinal muscle atrophy after surgery. We investigated 1-year postoperative changes in paraspinal muscle volume using a simple formula applicable to magnetic resonance imaging (MRI) or computed tomography (CT) images.

Methods

Patients with degenerative lumbar spinal stenosis who underwent posterior interbody fusion (PLIF) at the L4/5 level in the period from May 2010 to June 2017 were enrolled in this study. Radiologic parameters were measured using MRI or CT images which were taken before surgery and at 1 year after surgery. The volume of the paraspinal muscles was calculated using a simple formula which was derived from the formula for calculating the volume of truncated elliptic cones.

Results

A total of 40 patients were included; 24 were analyzed using MRI and 16 were analyzed using CT. The mean age of the patients was 59.6 ± 12.1 years and 32 (80.5%) were female. When comparing the preoperative and 1-year-postoperative images, multifidus muscle (MF) reduction was consistently observed in the MRI and CT groups, right and left (p = 0.003, p < 0.001, p = 0.005 and p < 0.001, respectively). In the erector spinae (ES) group, decrease in muscle volume was observed in the right-sided muscles of the CT group (p < 0.001), but no significant change was observed in the MRI group. The psoas muscle showed no significant change after 1 year. Conversely, regression analysis showed a negative correlation between MF muscle volume loss and age in the MRI group (right and left, p = 0.002 and p = 0.015, respectively), that is, the younger the age, the greater loss of muscle mass.

Conclusion

After the posterior lumbar fusion, the volume of the MF muscles was markedly decreased, and the degree of decrease was apparent in the MRI. The volume of the ES muscles, which are located relatively laterally, also tended to decrease at 1 year after surgery.

Palliative Liver Radiotherapy (RT) for Symptomatic Hepatocellular Carcinoma (HCC)

This study aims at evaluating the symptom response, response duration, and toxicity of single dose palliative liver radiotherapy (RT) for symptomatic HCC patients. We reviewed unresectable HCC patients treated with palliative RT in our institution. Eligible patients were unsuitable or refractory to trans-arterial chemoembolization (TACE) and stereotactic body radiotherapy (SBRT), with an index symptom of pain or abdominal discomfort. The primary outcome was the percentage of patients with clinical improvement of index symptom at 1 month. Secondary outcomes were response duration, toxicities, alpha-feto protein (AFP) response, and radiological response. Fifty-two patients were included in the study. The index symptom was pain in 34 patients (65.4%), and abdominal discomfort (34.6%) in 18 patients. At 1 month, 51.9% of patients had improvement of symptoms. Median time to symptom progression was 89 days (range: 12–392 days). Treatment was well tolerated with only 2 patients (3.8%) developing grade 3 GI toxicities. AFP response, radiological response rate, and disease control rate at 3 months were 48.6%, 15.1%, and 54.5% respectively. Half of the patients had improvement of index symptoms after receiving palliative liver RT with median response duration of 3 months. The treatment was well tolerated with minimal toxicities.

Analysis of the Factors Affecting Surgical Site Infection and Bone Flap Resorption after Cranioplasty with Autologous Cryopreserved Bone: The Importance of Temporalis Muscle Preservation

AIM

To investigate the outcomes and associated complications after delayed cranioplasty using autologous, cryopreserved bone.

MATERIAL AND METHODS

This retrospective study included 57 consecutive patients treated with cranioplasty with autologous cryopreserved bone for various conditions causing increased intracranial pressure due to brain swelling. The incidence and risk factor of surgical site infection (SSI) and bone flap resorption were analyzed.

RESULTS

The SSI rate was 12.3% and the bone flap resorption rate was 24.0%. There were statistically significant differences in SSI rate in relation to time from craniectomy to cranioplasty (p=0.002) and previous temporalis muscle resection (p=0.021). These factors were also independently associated with surgical site infection (time from craniectomy to cranioplasty: OR 0.901, 95% CI 0.826?0.982, p=0.018; previous temporalis muscle resection: OR 11.607, 95% CI 1.155?116.590, p=0.037). There was also a statistically significant difference in the bone flap resorption rate in relation to previous temporalis muscle resection (p=0.001). This factor was associated with bone flap resorption (OR 11.667, 95% CI 2.276?59.798, p=0.003).

CONCLUSION

The risk of these complications particularly increased after previous temporalis muscle resection. Based on this finding, we believe that preservation of the temporalis muscle may help to decrease postoperative complications after autologous cranioplasty.

S100ß, Matrix Metalloproteinase-9, D-dimer, and Heat Shock Protein 70 Are Serologic Biomarkers of Acute Cerebral Infarction in a Mouse Model of Transient MCA Occlusion

Objective

Diagnosing acute cerebral infarction is crucial in determining prognosis of stroke patients. Although many serologic tests for prompt diagnosis are available, the clinical application of serologic tests is currently limited. We investigated whether S100β, matrix metalloproteinase-9 (MMP-9), D-dimer, and heat shock protein 70 (HSP70) can be used as biomarkers for acute cerebral infarction.

Methods

Focal cerebral ischemia was induced using the modified intraluminal filament technique. Mice were randomly assigned to 30-minute occlusion (n=10), 60-minute occlusion (n=10), or sham (n=5) groups. Four hours later, neurological deficits were evaluated and blood samples were obtained. Infarction volumes were calculated and plasma S100β, MMP-9, D-dimer, and HSP70 levels were measured using enzyme-linked immunosorbent assay.

Results

The average infarction volume was 12.32±2.31 mm³ and 46.9±7.43 mm³ in the 30- and 60-minute groups, respectively. The mean neurological score in the two ischemic groups was 1.6±0.55 and 3.2±0.70, respectively. S100β, MMP-9, and HSP70 expressions significantly increased after 4 hours of ischemia (p=0.001). Furthermore, S100β and MMP-9 expressions correlated with infarction volumes (p<0.001) and neurological deficits (p<0.001). There was no significant difference in D-dimer expression between groups (p=0.843). The area under the receiver operating characteristic curve (AUC) showed high sensitivity and specificity for MMP-9, HSP70 (AUC=1), and S100β (AUC=0.98).

Conclusion

S100β, MMP-9, and HSP70 can complement current diagnostic tools to assess cerebral infarction, suggesting their use as potential biomarkers for acute cerebral infarction.

The Potential of Diffusion-Weighted Magnetic Resonance Imaging for Predicting the Outcomes of Chronic Subdural Hematomas

Objective

Diffusion-weighted magnetic resonance imaging (DW-MRI) has proven useful in the study of the natural history of ischemic stroke. However, the potential of DW-MRI for the evaluation of chronic subdural hematoma (CSDH) has not been established. In this study, we investigated DW-MRI findings of CSDH and evaluated the impact of the image findings on postoperative outcomes of CSDH.

Methods

We studied 131 CSDH patients who had undergone single burr hole drainage surgery. The images of the subdural hematomas on preoperative DW-MRI and computed tomography (CT) were divided into three groups based on their signal intensity and density: 1) homogeneous (iso or low) density on CT and homogeneous low signal intensity on DW-MRI; 2) homogeneous (iso or low) density on CT and mixed signal intensity on DW-MRI; and 3) heterogeneous density on CT and mixed signal intensity on DW-MRI. On the basis of postoperative CT, we also divided the patients into 3 groups of surgical outcomes according to residual hematoma and mass effect.

Results

Analysis showed statistically significant differences in surgical (A to B: p<0.001, A to C: p<0.001, B to C: p=0.129) and functional (A to B: p=0.039, A to C: p<0.001, B to C: p=0.108) outcomes and treatment failure rates (A to B: p=0.037, A to C: p=0.03, B to C: p=1) between the study groups. In particular, group B and group C showed worse outcomes and higher treatment failure rates than group A.

Conclusion

CSDH with homogeneous density on CT was characterized by signal intensity on DW-MRI. In CSDH patients, performing DW-MRI as well as CT helps to predict postoperative treatment failure or complications.

Increased Ratio of Superficial Temporal Artery Flow Rate After Superficial Temporal Artery-to-Middle Cerebral Artery Anastomosis: Can It Reflect the Extent of Collateral Flow?

OBJECTIVE

There are several ways to identify donor artery patency and success of surgery after an anastomosis of the superficial temporal artery (STA) to the middle cerebral artery (MCA). The purpose of this study was to evaluate the ratio of bilateral STA mean flow rate (MFR) with the use of color Doppler ultrasonography (CDUS) after bypass surgery and to confirm the possibility of this value as a predictor of the extent of collateral flow.

METHODS

Eleven consecutive patients who had undergone STA-MCA anastomosis were included. In every case, bilateral STA MFR, mean velocity, and cross-sectional diameter were measured preoperatively and postoperatively at 1 week, 1 month, and 2 months via CDUS. We measured the bilateral STA MFR ratio changes to compensate for systemic hemodynamic variables.

RESULTS

One month after surgery, 9 of the 11 patients who underwent STA-MCA anastomosis had good patency on DSA. In patients with good patency, there was a significant increase in the baseline STA MFR ratio compared with those at 1 week, 1 month, and 2 months postoperatively (2.88, 3.07, and 4.38, respectively, P < 0.05). The mean STA cross-sectional diameter ratio also was significantly increased postoperatively in the good patency group (1.35, 1.41, and 1.49, respectively, P = 0.044). In addition, the mean STA mean velocity ratio was increased postoperatively in the good patency group (1.48, 1.40, and 1.67, respectively, P = 0.042).

CONCLUSIONS

We conclude that using CDUS to measure both STA MFR ratio is a potential method to predict the extent of collateral flow through an STA-MCA anastomosis.

Efficacy of superficial temporal artery-middle cerebral artery bypass in cerebrovascular steno-occlusive diseases: Hemodynamics assessed by perfusion computed tomography

OBJECTIVES

Our purpose of this study was to assess the cerebral hemodynamic improvement with perfusion computed tomography (CT), before and after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery in patients with cerebrovascular steno-occlusive diseases including both moyamoya disease and nonmoyamoya steno-occlusions.

MATERIALS AND METHODS

Twenty-four STA-MCA bypasses were performed to 22 patients with symptomatic cerebrovascular steno-occlusive diseases, including both moyamoya disease and nonmoyamoya steno-occlusive diseases. Brain perfusion CT images were obtained before and after the bypass surgery. The relative parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) derived from the perfusion CT were collected and analyzed to assess the efficacy of STA-MCA bypass.

RESULTS

The CBF increased, and MTT decreased after the bypass surgery in both moyamoya group and nonmoyamoya group. The increase of CBF in nonmoyamoya group and the decrease of MTT delay in moyamoya group, overall group were statistically significant (P < 0.05). No significant postoperative change in CBV was noted. During the postoperative follow-up period, none of the 22 patients experienced any repeated ischemic/hemorrhagic attacks nor any newly developed neurologic deficits.

CONCLUSION

The STA-MCA bypass is an effective surgical management for patients with cerebrovascular steno-occlusive diseases, such as moyamoya disease and internal carotid artery/MCA steno-occlusion. And perfusion CT can be used as an effective quantitative modality to assess the cerebral perfusion before and after the STA-MCA bypass surgery.

Subdural Hematoma without Subarachnoid Hemorrhage Caused by the Rupture of Middle Cerebral Artery Aneurysm

Pure subdural hematomas caused by a ruptured intracranial aneurysm are extremely rare. We describe the case of a 42-year-old woman who presented with headache without evidence of head trauma. Magnetic resonance angiography and conventional cerebral angiography revealed a ruptured aneurysm at the right middle cerebral artery bifurcation. The patient underwent surgical treatment and had a good outcome without any neurological deficit. The mechanisms and clinical characteristics of this condition are discussed.

Endovascular Treatment of Symptomatic Vertebral Artery Dissecting Aneurysms

Objective

Vertebral artery dissecting aneurysms (VADAs) are rare and many debates are present about treatment options. We review types and efficacy of our endovascular treatments and establish a safe endovascular therapeutic strategy regard to the angio-architecture of VADAs.

Materials and Methods

Between July 2008 and October 2015, we treated 22 patients with symptomatic VADAs. Fifteen patients presented with subarachnoid hemorrhage from the ruptured VADAs, digital subtraction angiography and magnetic resonance image confirmed the diagnosis and endovascular treatments were followed as their angio-architecture.

Results

Clinical results were good in 13 patients (86.7%), and there were no technical problems during endovascular procedures. The other 2 patients with poor prognosis showed severe neurological deficits at the initial evaluation. Among the three different endovascular treatments, there were no radiologic cure in one patient with stent insertion alone, but the patient had no significant clinical symptoms either.

Conclusion

Endovascular treatments are safe and effective treatment option for managing VADAs and can be the first treatment of choice for most patients. To select proper endovascular treatment according to the angio-architecture of VADAs can reduce the risk of the treatment.

Biomechanical Changes in Disc Pressure and Facet Strain after Lumbar Spinal Arthroplasty with CharitéTM in the Human Cadaveric Spine under Physiologic Compressive Follower Preload

AIM

Arthroplasty maintains the biomechanical features of a healthy disc, decreases the adjacent segment disease rate, and decreases the accelerated degeneration rate of the neighboring discs in traditional fusion procedures. However, there are only a few reports on adjacent disc pressure (DP) and facet strain (FS) after lumbar arthroplasty under a physiologic compressive preload.

MATERIAL AND METHODS

Baseline DP and FS measurements were obtained from five intact cadaveric human lumbosacral spines for different modes of motion. DP was measured by inserting pressure transducer needle tips into the L3-L4 and L5-S1 discs. FS gauges were fixed on both sides of the laminae near the L3-L4, L4-L5, and L5-S1 facet joints. After SB Charité < sup > TM < /sup > III implantation at the L4-L5 level, the measurements were repeated at preload and compared with those of the intact spine.

RESULTS

Under the preload condition, the central DP of the upper disc was decreased during extension and bending, and it significantly increased during rotation (p < 0.05). In the lower disc, the central DP insignificantly decreased during bending and increased during extension and flexion. A statistically significant increase in FS was observed during rotation at the operative facet (p < 0.05). Compared to the intact spine, all FS values were insignificantly decreased during lateral bending but increased during axial rotation.

CONCLUSION

In an ex-vivo physiologic preload setting, the SB Charité < sup > TM < /sup > III provided relatively inconsistent and sometimes increased DP or FS at the operative and adjacent levels after arthroplasty.

Is Routine Repeated Head CT Necessary for All Pediatric Traumatic Brain Injury?

Objective

Repeated computed tomography (CT) follow up for traumatic brain injury (TBI) patients is often performed. But there is debate the indication for repeated CT scans, especially in pediatric patients. Purpose of our study is to find risk factors of progression on repeated CT and delayed surgical intervention based on the repeated head CT.

Methods

Between March, 2007 and December, 2013, 269 pediatric patients (age 0-18 years) had admitted to our hospital for head trauma. Patients were classified into 8 subgroups according to mechanisms of injury. Types, amount of hemorrhage and amount changes on repeated CT were analyzed as well as initial Glasgow Coma Scale (GCS) scores.

Results

Within our cohort of 269 patients, 174 patients received repeat CT. There were progression in the amount of hemorrhage in 48 (27.6%) patients. Among various hemorrhage types, epidural hemorrhage (EDH) more than 10 cc measured in initial CT was found to be at risk of delayed surgical intervention significantly after routine repeated CT with or without neurological deterioration than other types of hemorrhage. Based on initial GCS, severe head trauma group (GCS 3-8) was at risk of delayed surgical intervention after routine repeated CT without change of clinical neurologic status.

Conclusion

We suggest that the patients with EDH more than 10 cc or GCS below 9 should receive repeated head CT even though absence of significant clinical deterioration.

Traumatic Subarachnoid Hemorrhage Originating from Mid-Cervical Arterial Injury

BACKGROUND

Subarachnoid hemorrhage (SAH) occasionally originates from extracranial arteries, and SAH caused by cervical trauma is even rarer.

CASE REPORT

A 17-year-old male patient was admitted to our emergency department aftera bike accident; he was drowsy and showed left hemiparesis. Initial computed tomography (CT) of the brain showed SAH into the cervicomedullary cistern. A 4-hour follow-up brain CT revealed heavy bleeding into the basal cistern. Because CT angiography did not show any vascular injury, we performed imaging studies of the cervical spine. Magnetic resonance imaging revealed a blood clot located ventral to the C4-C5 level of the spinal cord without any flow void. The patient's condition deteriorated over time, and he was accordingly referred for surgery. Intraoperatively, a thick subarachnoid hematoma ventral to the spinal cord was observed. The hematoma was removed and hemostasis by bipolar cauterization was performed for bleeding from a small branch of the anterior spinal artery. Postoperatively, the weakness of the lower extremity improved considerably.

CONCLUSION

In young adult patients with SAH of unexplained origin, we suggest that the cervical region be considered as the bleeding focus; in such cases, surgical evacuation of bleeding can save some patients.

Differential clinical outcomes following encephaloduroarteriosynangiosis in pediatric moyamoya disease presenting with epilepsy or ischemia

PURPOSE

The purpose of this study was to compare clinical outcomes and surgical results after encephaloduroarteriosynangiosis (EDAS) in pediatric patients with Moyamoya disease that manifested as either ischemia or epileptic seizures.

METHODS

We treated 23 children who underwent EDAS; we divided the patients into either ischemic or epileptic groups according to the individuals' clinical presentation. Group Ia included those who mainly presented with cerebral ischemia in the form of preoperative transient ischemic attacks (TIA), while Group Ib presented with ischemia in the form of irreversible neurologic deficits or proven cerebral infarcts. Group II included those who presented with epileptic seizures rather than cerebral ischemia. We compared the clinical outcomes and surgical results following EDAS in the three groups.

RESULTS

We grouped the patients into three groups according to their main preoperative clinical symptoms (Group Ia n = 10, Group Ib n = 6, and Group II n = 7). Group II, the epileptic manifestation group, tended to show more favorable clinical outcomes compared to the ischemic manifestation group, especially the severe ischemic group. However, there were no significant differences in postoperative neuroimaging and hemodynamic assessments between the groups.

CONCLUSIONS

EDAS is a safe and effective surgical technique that prevents epileptic seizures and shows more favorable clinical outcomes when used in patients with Moyamoya disease presenting with epileptic seizures compared to cerebral ischemia.

Unusual Presentation of Cerebral Cavernous Malformation

Cerebral cavernous malformations (CMs) are vascular malformations of the central nervous system, which can be detected in the absence of any clinical symptoms. Nodules and cysts with mixed signal intensity and a peripheral hemosiderin rim are considered brain magnetic resonance imaging (MRI) findings typical of CMs. A 48-year-old man was admitted to our hospital because of abnormal MRI findings without significant neurological symptoms. A cyst with an internal fluid-fluid level was found in the left basal ganglia on the initial brain MRI. We decided to observe the natural course of the asymptomatic lesion with serial MRI follow-up. On MRI at the 5-month follow-up, the cystic mass was enlarged and showed findings consistent with those of cystic CM. Surgical resection was performed and the pathological diagnosis was CM. Our experience suggests that the initial presentation of a CM can be a pure cyst and neurosurgeons should consider the likelihood of CMs in cases of cystic cerebral lesions with intracystic hemorrhage.

Hidden dense middle cerebral artery sign in a 4-year-old boy with traumatic subarachnoid hemorrhage

A 4-year-old boy was admitted with acute onset of hemiplegia of the right side that was secondary to a traffic accident. Initial computed tomography revealed a traumatic subarachnoid hemorrhage, and follow-up computed tomography showed a more localized hematoma of the left sylvian cistern. After a few days of conservative treatment, magnetic resonance imaging (MRI) revealed a cerebral infarction of the left lenticulostriate territory, even though magnetic resonance angiography showed preserved middle cerebral artery flow. Thus, we realized that the hematoma of the sylvian cistern was the so-called dense middle cerebral artery sign. This case of posttraumatic infarction suggested the importance of meticulous investigations and clinical correlations of imaging studies in pediatric patients with head injuries.

Modified Open-door Laminoplasty Using Hydroxyapatite Spacers and Miniplates

Objective

Cervical laminoplasty has been widely accepted as one of the major treatments for cervical myelopathy and various modifications and supplementary procedures have been devised to achieve both proper decompression and stability of the cervical spine. We present the retrospectively analyzed results of a modified unilateral open-door laminoplasty using hydroxyapatite (HA) spacers and malleable titanium miniplates.

Methods

From June 2008 to May 2012, among patients diagnosed with cervical spondylotic myelopathy and ossification of posterior longitudinal ligament, the patients who received laminoplasty were reviewed. Clinical outcome was assessed using Frankel grade and Japanese Orthopaedic Association score. The radiologic parameters were obtained from plain films, 3-dimensional computed tomography and magnetic resonance images.

Results

A total of 125 cervical laminae were operated in 38 patients. 11 patients received 4-level laminoplasty and 27 patients received 3-level laminoplasty. Postoperatively, the mean Frankel grade and JOA score were significantly improved from 3.97 to 4.55 and from 12.76 to 14.63, respectively (p<0.001). Radiologically, cervical curvature was worsened from 19.09 to 15.60 (p=0.025). The percentage of range of motion preservation was 73.32±22.39%. The axial dimension of the operated spinal canal was increased from 1.75 to 2.70 cm² (p<0.001).

Conclusion

In the presenting study, unilateral open-door laminoplasty using HA spacers and miniplates appears to be a safe, rapid and easy procedure to obtain an immediate and rigid stabilization of the posterior elements of the cervical spine. This modified laminoplasty method showed effective expansion of the spinal canal and favorable clinical outcomes.

Semi-quantitative analyses of hippocampal heat shock protein-70 expression based on the duration of ischemia and the volume of cerebral infarction in mice

Objective

We investigated the expression of hippocampal heat shock protein 70 (HSP-70) infarction volume after different durations of experimental ischemic stroke in mice.

Methods

Focal cerebral ischemia was induced in mice by occluding the middle cerebral artery with the modified intraluminal filament technique. Twenty-four hours after ischemia induction, both hippocampi were extracted for HSP-70 protein analyses. Slices from each hemisphere were stained with 2,3,5-triphenyltetrazolium chloride (2%), and infarction volumes were calculated. HSP-70 levels were evaluated using western blot and enzyme-linked immunosorbent assay (ELISA). HSP-70 subtype (hsp70.1, hspa1a, hspa1b) mRNA levels in the hippocampus were measured using reverse transcription-polymerase chain reaction (RT-PCR).

Results

Cerebral infarctions were found ipsilateral to the occlusion in 10 mice exposed to transient ischemia (5 each in the 30-min and 60-min occlusion groups), whereas no focal infarctions were noted in any of the sham mice. The average infarct volumes of the 2 ischemic groups were 22.28±7.31 mm³ [30-min group±standard deviation (SD)] and 38.06±9.53 mm³ (60-min group±SD). Western blot analyses and ELISA showed that HSP-70 in hippocampal tissues increased in the infarction groups than in the sham group. However, differences in HSP-70 levels between the 2 infarction groups were statistically insignificant. Moreover, RT-PCR results demonstrated no relationship between the mRNA expression of HSP-70 subtypes and occlusion time or infarction volume.

Conclusion

Our results indicated no significant difference in HSP-70 expression between the 30- and 60-min occlusion groups despite the statistical difference in infarction volumes. Furthermore, HSP-70 subtype mRNA expression was independent of both occlusion duration and cerebral infarction volume.

Comparison of subgroups based on hemorrhagic lesions between SWI and FLAIR in pediatric traumatic brain injury

PURPOSE

The purpose of this study was to investigate efficient ways to diagnose and predict clinical outcomes for childhood traumatic brain injury.

METHODS

Hemorrhagic signal intensities in nine brain regions were observed using axial fluid-attenuated inversion recovery (FLAIR) and susceptibility-weighted imaging (SWI). After having divided the subjects into mild presentation (GCS 14-15) and moderate-to-severe presentation groups (GCS ≤13), we divided the patients into three subgroups: Subgroup I, hemorrhagic foci observed only on SWI and not on FLAIR; Subgroup II, hemorrhagic foci observed on both SWI and FLAIR in the same brain regions; and Subgroup III, any cases with additional foci on SWI in other brain regions. We investigated the clinical course and compared lesion numbers and distributions of hemorrhagic lesions on SWI among the subgroups.

RESULTS

Three clinical variables (hospitalization period in intensive care unit, total days of hospitalization, and outcome based on Pediatric Cerebral Performance Category Scale score) showed significant relevance to the three subgroups. Subgroup I showed the fewest lesions followed by Subgroups II and III, respectively. In all three subgroups, lesions were most abundant in cortical regions. Lesion in the thalamus, basal ganglia, corpus callosum, and brainstem was least in Subgroup I and gradually increased in Subgroups II and III. Such distinction was more significant in the moderate-to-severe group when compared with the mild group.

CONCLUSIONS

In cases of pediatric traumatic brain injury, categorizing patients into one of the above three subgroups based on hemorrhagic lesions on SWI and FLAIR is a promising method for predicting patient's clinical outcome.

Triple primary origin tumor: a case report

Generally, among the extradural spinal tumors, metastatic spinal tumor is much more common than primary spinal tumors. Thus, in the case of a spinal tumor patient with cancer history (such as lung cancer, breast cancer, etc.), we used to infer that the spinal lesion is the metastasis from, primary malignancy. We introduce an experience of a case of triple primary origin tumor in a 57-year-old man. When the spinal lesion was found on the abdominal computed tomography scan, he already had a history of colon cancer and liver cancer. Initially, it was thought that the lesion would probably be a metastatic tumor from the liver or colon cancers, and the operation was performed accordingly. In the pathologic final report, however, the mass was proven to plasmacytoma - the third primary lesion. The patient underwent chemotherapy after surgery. Globally, the triple primary origin tumor has been reported very rarely. With this report, we wish to emphasize the necessity of pathologic confirmation and adequate treatment even in a patient with known malignancies.

Late infection from anterior cervical discectomy and fusion after twenty years

Anterior cervical discectomy and fusion (ACDF) has been performed for degenerative and traumatic cervical diseases to improve pain and neurologic symptoms including sensory change and motor weakness. Infection, however, is a rare complication of ACDF, and late infection is even much rarer. We present a case of late Infection from ACDF C4-5 using Biocompatible Osteoconductive Polymer (BOP) after twenty years in the absence of an esophageal perforation, Zenker's diverticulum, or recent surgery or bacteremia. Late infection from ACDF after 20 years is extremely rare in the literature. However, possibility of such a late complication should be appreciated during the follow-up period and surgical resection will be required for proper treatment.

Rupture of de novo anterior communicating artery aneurysm 8 days after the clipping of ruptured middle cerebral artery aneurysm

Rapidly developed de novo aneurysm is very rare. We present a rapidly developed and ruptured de novo anterior communicating aneurysm 8 days after the rupture of another aneurysm. This de novo aneurysm was not apparent in the initial 3-dimensional computed tomography and digital subtraction angiography. We reviewed the literature and discussed possible mechanisms for the development of this de novo aneurysm.

The role of adiponectin in secondary inflammatory reaction in cerebral ischemia

Objective

In this study, we investigate the role of adiponectin in the interaction between leukocytes and endothelium in the secondary inflammatory reaction of cerebral ischemia.

Methods

Adiponectin knock-out mice group (APN-KO) (n = 8) and wild-type mice group (WT) (n = 8) were prepared. Each group was sub-divided into 2 groups by reperfusion time. One-hour middle cerebral artery occlusion and reperfusion were induced using the intraluminal filament technique. At 6 and 12 hours after the occlusion, the mice were placed on a stereotactic frame to perform craniotomy in the left parietal area. After craniotomy, a straight pial venule was selected as a target vessel. With the fluorescence intravital microscope, the number of rolling leukocytes and leukocytes that adhered to endothelium were counted and documented at 6 and 12 hours after the reperfusion.

Results

At 6 and 12 hours after the reperfusion, more rolling leukocyte and leukocyte adhesion were observed in the APN-KO mice than in the WT mice. The difference in leukocyte numbers between the APN-KO and WT mice was found to be statistically significant (p = 0.029) by Mann-Whitney U-test.

Conclusion

We found that adiponectin inhibits the interaction between the endothelium and leukocytes in cerebral ischemia-reperfusion. Therefore adiponectin might prevent the secondary insult caused by the inflammation reaction.

Fatal case of cerebral aspergillosis : a case report and literature review

Cerebral aspergillosis is rare and usually misdiagnosed because its presentation is similar to that of a tumor. The correct diagnosis is usually made intra-operatively. Cerebral abscess with fungal infection is extremely rare and few cases have been reported, but it carries a poor prognosis.

A 73 year-old man presented with decreased visual acuity and paresis of the right cranial nerve III. Magnetic resonance imaging (MRI) revealed a mass in the right cavernous sinus, extened to the anterior crainial fossa and the superior orbital fissure. During surgery, a well encapsulated pus pocket was found, and histopathological examination of the mass resulted in the diagnosis of aspergillosis. Despite appropriate anti-fungal treatment, the patient eventually died from fatal cerebral ischemic change and severe brain swelling.

The correct diagnosis of cerebral aspergillosis can only be achieved by histopathological examination because clinical and radiological findings including MRI are not specific. Surgical intervention and antifungal therapy should be considered the optimal treatment. Early diagnosis and aggressive antifungal treatment provide good results.

Analysis of multiple factors affecting surgical outcomes of proximal middle cerebral artery aneurysms

OBJECTIVE

We analyzed multiple factors including anatomical characteristics that influence the surgical outcomes of proximal middle cerebral artery (M1) aneurysms.

METHODS

Between January 1999 and February 2007, 189 patients had middle cerebral artery aneurysms and 60 had M1 aneurysms. Eleven patients were excluded from this study. The aneurysms were classified into two groups (superior- and inferior-wall type). Retrospectively, we evaluated characteristics of these patients and investigated factors affecting surgical outcomes.

RESULTS

Of the 49 patients, 28 had ruptured aneurysms and 43 had aneurysms sized less than 10mm in diameter. There were no giant aneurysms, the incidence of multiple aneurysms was high (22 patients, 45%), and intracerebral hematomas (ICH) were recognized in 13 patients (27%). The superior-wall group included 29 patients (59.2%) and the inferior-wall group had 20 (40.8%). Overall mortality and morbidity rates were 6.1% and 24.5%, respectively. Thirty-four patients (69%) showed good outcomes (GOS 4-5). Eleven and five patients showed unfavorable outcomes from the superior- and inferior-wall group, respectively. Of the four operation-related morbidity patients, three were from the superior-wall and one from the inferior-wall group. There were no statistically significant differences with respect to clinical outcome between the superior- and inferior-wall groups. Patients with poor Hunt-Hess (H-H) grades on admission showed worse outcomes than those with good H-H grades (p=0.002) and those patients without ICH revealed better outcomes than those with ICH (p=0.004).

CONCLUSIONS

In patients with M1 aneurysms, clinical status on admission and the presence of ICH were significant factors for surgical outcome. Surgical morbidity seems to be related to the direction of the aneurysm. It is critical to save the lenticulostriate arteries and their branches in patients with superior-wall type aneurysms. Thorough preoperative angiographic evaluation, careful brain retraction, and meticulous inspection for hidden small branches are crucial to successful outcomes.

Risk of stroke with temporary arterial occlusion in patients undergoing craniotomy for cerebral aneurysm

OBJECTIVE

This study was performed to elucidate the technical and patient-specific risk factors for postoperative ischemia in patients undergoing temporary arterial occlusion (TAO) during the surgical repair of their aneurysms.

METHODS

Eighty-nine consecutive patients in whom TAO was performed during surgical repair of an aneurysm were retrospectively analyzed. The demographics of the patients were analyzed with respect to age, Hunt and Hess grade on admission, Fisher grade of hemorrhage, aneurysm characteristics, timing of surgery, duration of temporary occlusion, and number of temporary occlusive episodes. Outcome was analyzed at the 3-month follow-up, along with the occurrence of symptomatic and radiological stroke.

RESULTS

In overall, twenty-seven patients (29.3%) had radiologic ischemia attributable to TAO and fifteen patients (16.3%) had symptomatic ischemia attributable to TAO. Older age and poor clinical grade were associated with poor clinical outcome. There was a significantly higher rate of symptomatic ischemia in patients who underwent early surgery (p = 0.007). The incidence of ischemia was significantly higher in patients with TAO longer than 10 minutes (p = 0.01). In addition, patients who underwent repeated TAO, which allowed reperfusion, had a lower incidence of ischemia than those who underwent single TAO lasting for more than 10 minutes (p = 0.011).

CONCLUSION

Duration of occlusion is the only variable that needs to be considered when assessing the risk of postoperative ischemic complication in patients who undergo temporary vascular occlusion. Attention must be paid to the patient's age, grade of hemorrhage, and the timing of surgery. In addition, patients undergoing dissection when brief periods of temporary occlusion are performed may benefit more from intermittent reperfusion than continuous clip application. With careful planning, the use of TAO is a safe technique when used for periods of less than 10 minutes.

Biomechanical study of lumbar spinal arthroplasty with a semi-constrained artificial disc (activ L) in the human cadaveric spine

OBJECTIVE

The goal of this study was to evaluate the biomechanical features of human cadaveric spines implanted with the Activ L prosthesis.

METHODS

Five cadaveric human lumbosacral spines (L2-S2) were tested for different motion modes, i.e. extension and flexion, right and left lateral bending and rotation. Baseline measurements of the range of motion (ROM), disc pressure (DP), and facet strain (FS) were performed in six modes of motion by applying loads up to 8 Nm, with a loading rate of 0.3 Nm/second. A constant 400 N axial follower preload was applied throughout the loading. After the Activ L was implanted at the L4-L5 disc space, measurements were repeated in the same manner.

RESULTS

The Activ L arthroplasty showed statistically significant decrease of ROM during rotation, increase of ROM during flexion and lateral bending at the operative segment and increase of ROM at the inferior segment during flexion. The DP of the superior disc of the operative site was comparable to those of intact spine and the DP of the inferior disc decreased in all motion modes, but these were not statistically significant. For FS, statistically significant decrease was detected at the operative facet during flexion and at the inferior facet during rotation.

CONCLUSION

In vitro physiologic preload setting, the Activ L arthroplasty showed less restoration of ROM at the operative and adjacent levels as compared with intact spine. However, results of this study revealed that there are several possible theoretical useful results to reduce the incidence of adjacent segment disease.

Radiologic Assessment of Subsidence in Stand-Alone Cervical Polyetheretherketone (PEEK) Cage

OBJECTIVE

Aim of study was to find a proper method for assessing subsidence using a radiologic measurement following anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK), Solistrade mark cage.

METHODS

Forty-two patients who underwent ACDF with Solistrade mark cage were selected. With a minimum follow-up of 6 months, the retrospective investigation was conducted for 37 levels in 32 patients. Mean follow-up period was 18.9 months. Total intervertebral height (TIH) of two fused vertebral bodies was measured on digital radiographs with built-in software. Degree of subsidence (DeltaTIH) was reflected by the difference between the immediate postoperative and follow-up TIH. Change of postoperative disc space height (CT-MRDeltaTIH) was reflected by the difference between TIH of the preoperative mid-sagittal 2D CT and that of the preoperative mid-sagittal T1-weighted MRI.

RESULTS

Compared to preoperative findings, postoperative disc height was increased in all cases and subsidence was observed only in 3 cases. For comparison of subsidence and non-subsidence group, TIH and CT-MRDeltaTIH of each group were analyzed. There was no statistically significant difference in TIH and CT-MRDeltaTIH between each group at 4 and 8 weeks, but a difference was observed at the last follow-up TIH (p=0.0497).

CONCLUSION

ACDF with Solistrade mark cage was associated with relatively good radiologic long-term results. Fusion was achieved in 94.5% and subsidence occurred in 8.1% by the radiologic assessment. Statistical analysis reveals that the subsidence seen later than 8 weeks after surgery and the development of subsidence does not correlate statistically with the change of the postoperative disc space height.

Anti-microbial susceptibility for east1 + Escherichia coli isolated from diarrheic pigs in Korea

The in vitro susceptibilities of 128 isolates of east1 + Escherichia coli from pre-weaned and post-weaned pigs with diarrhoea were tested with nine commonly used anti-microbial agents by an agar dilution minimal inhibitory concentration (MIC) procedure according to National Committee for Clinical Laboratory Standards guidelines. For the isolates from preweaned and post-weaned pigs, most of them were susceptible to low concentrations (MIC90) of tetracycline (4 and 2 microg/ml), ceftiofur (2 and 2 microg/ml), and colistin (4 and 2 microg/ml). Marked resistance was found in others.

Clinical outcome in continuous ambulatory peritoneal dialysis patients is not influenced by high peritoneal transport status

OBJECTIVES

We undertook this study to examine the influence of demographics, peritoneal membrane transport characteristics, nutrition indices, dialysis adequacy, and comorbid diseases on patient survival on continuous ambulatory peritoneal dialysis (CAPD), and to identify whether high peritoneal membrane transport is an independent risk factor for mortality on CAPD.

DESIGN

Our retrospective study was carried out in CAPD patients in a large tertiary care teaching hospital.

METHODS

Until December 2000, we followed 212 patients who started CAPD between 1994 and 1997 and who underwent a peritoneal equilibration test (PET) within 3 months of CAPD initiation.

RESULTS

By univariate analysis, comorbid diseases, old age, high peritoneal transport, and serum albumin predicted patient mortality. Independent predictors of mortality as determined by the Cox proportional hazard model included diabetes mellitus, cardiovascular disease, serum albumin, and old age. High peritoneal transport failed to independently influence mortality in our CAPD patients.

Admittance matrix of asymmetric piezoelectric bimorph with two separate electrical ports under general distributed loads

The dynamic admittance matrix of the asymmetric triple-layer piezoelectric bimorph subjected to the general distributed harmonic loads as well as the flexural moments and the vertical loads at the tip are presented. The top and bottom piezoelectric layers have two separate electrical ports such that each layer can be used as either a sensor or an actuator. The variation principle is used for deriving the motion equations and the conjugate parameters that maintain the symmetry of the admittance matrix. The mechanical displacements and forces at the tip are expressed in a matrix form, which, together with the reciprocal condition, greatly simplify the analysis procedure. The derived admittance matrix under the cantilevered condition is presented by a five-by-five matrix, each row representing the relationships of the displacement and rotation at the tip, the volume averaged displacement, the separate electrical charges with the flexural moment and vertical load at the tip, the magnitude of the distributed load, and the voltages. The matrices, which reduce to simpler forms for several special cases, are then used to determine the two-port electrical admittance. It is shown that the derived admittance matrix covers the various boundary conditions, the electrical parallel and series connections, and the arbitrary lay-up, including the unimorph, used as both sensors and actuators.

Long-term outcome of kidney transplantation in adult recipients with focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is an important cause of nephrotic syndrome and end-stage renal disease. FSGS recurrence after renal transplantation has a potentially detrimental course leading to the loss of renal function. In order to establish FSGS recurrence rates and evaluate the course of the disease on living-related-donor renal transplantation in ethnic Korean adults (> or = 18 years), we reviewed our experiences of 27 kidney transplantations with FSGS over the last 15 years. Of the 27 renal allografts, 13 were found to have recurrent FSGS by graft biopsy. In comparison with background data upon patients with and without recurrence of FSGS, the donor age of patients with recurrent FSGS was significantly higher than that of those without recurrence (median, 39 years vs 26, p < 0.05). In terms of, age at transplantation, length of dialysis period, and mode of dialysis no differences were found between recurrent and nonrecurrent cases. The graft survival rate of recipients from a kidney donor of age less than 40 years was significantly higher than that of recipients from a kidney donor of age more than 40 years, at 5 and 10 years, respectively (87% vs 33%, 41% vs 0%, p < 0.05). The association between clinical variables and recurrence was assessed by multiple logistic regression analysis, and donor age was found to be a risk factor of FSGS recurrence (p<0.05). Variables such as HLA-mismatch numbers and immunosuppression were not found to be associated. In conclusion, the recurrence rate of FSGS in adult recipients with FSGS was 48% and patients that received kidney from an older donor appear to be at higher risk of developing recurrence. The use of a renal graft from a younger donor is considered advisable for adult recipients with FSGS.

An analysis of 4,514 cases of renal biopsy in Korea

To evaluate the distribution and changing patterns of renal diseases in Korea, a total of 4,514 cases of renal biopsy collected over a 23-year period between 1973 and 1995 were reviewed. Of 4,200 cases excluding 314 unsatisfactory biopsies, adult cases comprised 59.5% and pediatric cases, 40.5%. The male to female ratio was 1.5:1 in adults and 2.2:1 in children. Glomerulonephritis (GN) comprised 80.0% of the total. The most common primary GN in adults was minimal change disease (MCD) (26.6%), followed by IgA nephropathy (IgAN) (22.1%), membranous GN (MGN) (11.8%), and membranoproliferative GN (MPGN) (5.9%). In children, the primary GN incidence rates were MCD (24.8%), IgAN (10.3%), poststreptococcal (including postinfectious) GN (PSGN) (8.6%), and focal segmental glomerulosclerosis (FSGS) (4.0%). The most common secondary GN in adults was lupus nephritis and in children Henoch-Schonlein purpura nephritis. The most common cause of nephrotic syndrome was MCD in both adults and children, followed by MGN and FSGS. The elderly, aged sixty years and older, comprised 2.7% of cases and recorded equal numbers of MCD and MGN. The proportion of the biopsies found to be seropositive for HBs antigen was 27.9%, and these showed either MGN or MPGN pattern. Repeat biopsy was performed in 168 patients, due to previous biopsy failure in 15.5%. When the primary GN cases were analyzed at 5-year intervals, the prevalence of PSGN, which was greater than 25% during the 1973-1982 period, decreased abruptly in children thereafter, whereas the prevalence of FSGS increased slowly since the 1988-1992 period in both adults and children. The decrease of PSGN and the increase of FSGS suggest a role for socioeconomic and environmental factors in Korea.

Impedance and admittance matrices of symmetric piezoelectric annular bimorphs and their applications

The 5 x 5 impedance and admittance matrices of a symmetric triple-layer piezoelectric annular bimorph (PAB) are presented and the PAB with the piezoelectric layers partially covering the shim layer in harmonic motion is analyzed using the matrices. The electromechanical flow vectors are defined as the mechanical displacements and rotations at the inner and outer boundaries and the electric current of the piezoelectric layer; the conjugate parameters, i.e., the electromechanical effort vectors, are accordingly defined. The impedance matrix which relates the flow vector with the effort vector is divided into three matrices, the mechanical, electrical, and electromechanical coupling impedance matrices; each matrix is represented by a block network with five ports. The resonance and the antiresonance frequencies and the effective electromechanical coupling factors of the PAB excited by the partially covering piezoelectric layers are then calculated for various boundary conditions imposed at the inner and outer surfaces. The numerical results by the impedance matrix are compared with those by the finite element methods; they are in excellent agreement with each other. It is also shown that the matrix representations can be easily applied to the piezoelectric circular bimorph (PCB) with the extended shim layer.

ACE DD genotype is more susceptible than ACE II and ID genotypes to the antiproteinuric effect of ACE inhibitors in patients with proteinuric non-insulin-dependent diabetes mellitus

BACKGROUND

ACE polymorphism, especially genotype DD or D allele, may be involved in the progression of diabetic nephropathy. It may also have different effects on the reduction of proteinuria by ACE inhibitors in patients with proteinuria. We investigated the relationship between ACE gene polymorphism and antiproteinuric effect of ACE inhibitors (Benazepril 10 mg/day or Perindopril 4 mg/day) in 83 NIDDM patients with overt proteinuria (urinary protein excretion over 500 mg/day).

METHODS

We recruited NIDDM patients with overt proteinuria from our renal clinic. Before entry, previously used ACE inhibitors were withdrawn for at least 2 weeks and baseline proteinuria and albuminuria were measured. Patients were classified into three groups in accordance with ACE genotypes (17 DD; 33 ID; 33 II) and prospectively followed up for 3 months. Various clinical parameters including age, DM duration, body mass index (BMI), 24-h urine sodium, protein and albumin, BUN, serum creatinine, creatinine clearance (Ccr), mean arterial pressure (MAP), and HbA(1c) were measured in the pre- and post-treatment periods. ACE genotypes were determined by polymerase chain reaction.

RESULTS

There were no significant differences in the clinical parameters such as age, DM duration, BMI, BUN, serum creatinine, Ccr, MAP, HbA(1c), and daily urinary excretion of sodium, protein and albumin among three groups (P>0.05). After the 3-month treatment period using ACE inhibitors, there were no significant differences in the reduction of MAP and Ccr among the three groups (P>0.05). However, the percentage reductions in urinary excretion of protein and albumin for DD genotype were significantly higher than in ID and II genotypes (50.9+/-19.2% vs 19.2+/-16.0%, 20.2+/-20.4%; 52.6+/-23.6% vs. 13.5+/-51.8%, 24.8+/-23.9%, P<0.05). There were no statistically significant correlations between the levels of baseline proteinuria and albuminuria and the magnitudes of the reduction of proteinuria and albuminuria under ACE inhibition (P>0.05).

CONCLUSIONS

Our results suggest that the ACE gene polymorphism might have a role in determining the responsiveness to the antiproteinuric effect of ACE inhibition in proteinuric NIDDM patients.

Association between apolipoprotein E polymorphism and macroalbuminuria in patients with non-insulin dependent diabetes mellitus

OBJECTIVES

Apolipoprotein E (apo E) is known to play an important role in lipoprotein metabolism through its ability to bind to the receptors as a ligand. Three different apo E alleles (epsilon2, epsilon3 and epsilon4) produce six apo E genotypes (epsilon2/2, epsilon2/3, epsilon2/4, epsilon3/3, epsilon3/4 and epsilon4/4). The objective of this study was to investigate an association between apo E gene polymorphism and macroalbuminuria in 167 Korean patients with non-insulin dependent diabetes mellitus (NIDDM).

METHODS

The patients in the macroalbuminuria group (n = 74) represent those in whom 24 h urinary albumin excretion was above 300 mg. The patients in the normoalbuminuria group (n = 93) represent those in whom 24 h urinary albumin excretion was below 30 mg and serum creatinine levels were less than 1.2 mg/dl. The duration of diabetes in all patients was at least 8 years.

RESULTS

There were no significant differences in terms of age, sex, body mass index, HbA1c, total cholesterol, triglyceride, HDL-cholesterol and LDL-cholesterol between the two groups. In the macroalbuminuria group, the distribution of apo E genotypes revealed epsilon2/2 2 (2.7%), epsilon2/3 14 (18.9%), epsilon2/4 0 (0%), epsilon3/3 47 (63.5%), epsilon3/4 11 (14.9%) and epsilon4/4 0 (0%). In the normoalbuminuria group, the distribution of apo E genotypes revealed epsilon2/2 0 (0%), epsilon2/3 7 (7.5%), epsilon2/4 1 (1.1%), epsilon3/3 72 (77.4%), epsilon3/4 12 (12.9%) and epsilon4/4 1 (1.1%). There was no significant difference in the distribution of apo E genotypes between the two groups. However, there was a significant difference in the allele frequencies, epsilon2 frequency was significantly higher in macroalbuminuria group compared to normoalbuminuria group (12.2% vs 4.3%, P<0.05). Also, we compared apo E carrier frequencies between the two groups. Epsilon2 carrier frequency was significantly higher in macroalbuminuria group compared to normoalbuminuria group (21.6% vs 7.6%, P<0.05). In each group, there was no significant difference in the degree of lipid abnormalities between apo epsilon2 carrier (epsilon2/2, epsilon2/3 genotypes), epsilon3 carrier (epsilon3/3 genotype) and epsilon4 carrier (epsilon3/4, epsilon4/4 genotype).

CONCLUSION

Apo epsilon2 allele and epsilon2 carrier frequencies were significantly higher in macroalbuminuria group. These results suggest that epsilon2 allele may be associated with the development of clinical albuminuria in Korean patients with NIDDM.

Current status of peritoneal dialysis in Korea: efforts to achieve optimal outcome

Since its introduction in 1981, peritoneal dialysis (PD) has become firmly established as an effective mode of renal replacement therapy and serves an increasing patient population in Korea. The latest registry data indicate that about 3700 end-stage renal disease patients are maintained on chronic PD, representing 24.1% of the country's dialysis population. The majority (93.3%) of these patients are on continuous ambulatory peritoneal dialysis (CAPD) using the two-bag disconnect system, while only 3.3% are on automated PD. Under current renal reimbursement policies, most dialysis patients have to pay 20% of dialysis fees. Thus CAPD patients on 4 x 2-L daily exchanges pay about US$200 per month, not including medication and travel costs. Traditionally, most PD centers in Korea have used the "standard" prescription of 4 exchanges of 2 L of solution for most of their patients. A recent survey of 1467 patients who commenced CAPD in 1997 revealed that 84% of these patients were initially prescribed 4 x 2-L exchanges, while 12% were given a daily volume of 6 L. With this standard prescription, the percentages of Korean CAPD patients initially achieving the adequacy target of Kt/V urea > or = 2.0 and standardized creatinine clearance (SCCr) > or = 60 L/week/1.73 m2, were 74.4% and 82.1%, respectively. It is likely that, among current Korean CAPD patients, a much lower percentage will achieve the clearance targets compared to this initial outcome, but the precise data are not available. However, it is not clear whether the levels of small-solute clearance recommended for optimal PD outcomes, and proposed by the NKF-DOQI guidelines, will bring the expected benefits to Korean patients. Overall survival of Korean PD patients appears to be as good as, or even better than, that in most other countries. Recently, a single large PD center reported patient survival of 92.1%, 85.6%, 81.4%, and 67.6% at 1, 2, 3, and 5 years respectively. Other centers also reported similar outcomes. As in other countries, cardiovascular deaths predominate among Korean patients: death was due to cardiac causes in 29%, to vascular causes in 21%, and to infectious causes in 24%. Peritonitis is the most important barrier to prolonged use of CAPD in Korea, and more PD patients transfer to hemodialysis because of peritonitis than in other countries. To further reduce the morbidity and mortality of Korean PD patients, various control measures need to be implemented that can reduce or prevent peritonitis and other infectious complications. Also, to further improve long-term patient outcome, Korean nephrologists need to establish and practice optimal clearance targets in the chronic care of these patients.