Search

Background: Symptomatic vertebral artery dissecting aneurysm (VADA) is a challenging disease with controversy on treatment strategy due to anatomic configuration and their nature. Moreover, the outcomes of reconstructive treatment have not been well established. Objective: To evaluate the safety and efficacy of reconstructive endovascular treatment (EVT) for symptomatic VADAs with Willis covered stent. Methods: We evaluated retrospectively 13 patients with symptomatic VADAs who treated with Willis covered stent, compared with stent-assisted coiling (SAC) on the characteristics, posttreatment course, angiographic and clinical follow-up outcomes at an average of 14.4 months (range, 3–48 months). Results: A total of 33 patients with symptomatic VADAs were reviewed, 23 of these patients with ruptured VADAs. The technical successful rate is 100% respectively in Willis covered stent (Group A) and SAC (Group B, n ​= ​20). The initial complete occlusion rate was significant higher in group A (100%) than group B (30%) (p ​ ​0.05). No obvious in-stent stenosis and no re-hemorrhage and delayed ischemic symptoms during the follow-up period. The final angiograms of all survived patients demonstrated the complete occlusion rate was higher in group A (100%) than group B (80%), but no significant statistical difference (p ​> ​0.05). Clinical outcomes were favorable in 31 (93.9%), severe disability occurred in one in group B, and only one death in group A. The final clinical outcomes were also not significant difference in the two groups (p ​> ​0.05). Conclusions: Our initial result demonstrated reconstructive EVT with Willis covered stent provides a viable approach for selected symptomatic VADAs involving the intracranial and extracranial segments, which is similar to favorable results with SAC. However, an expanded clinical experiences and larger cohort studies are needed.

BACKGROUND: Posterior communicating artery (PcomA) aneurysms are more likely to recanalize than anterior communicating artery (AcomA) aneurysms. However, it is still unclear whether the recanalization rate of these aneurysms is a result of involvement from the fetal posterior cerebral artery (fPCA) in PcomA aneurysms and variation of the unilateral A1 segment in AcomA aneurysms. The purpose of this study is to retrospectively evaluate the different recanalization rates between PcomA aneurysms with fPCA and AcomA aneurysms with a variation of the unilateral A1 segment. METHODS: We retrospectively collected information regarding 214 patients, each with communicating segment aneurysms between January 2013 and January 2020. Follow-up documentation on clinical and imaging data was comparatively analyzed between variant types, and recanalization rates of the variant and normal types were analyzed by stratification. RESULTS: Of the 84 variant-type aneurysms (PcomA with fPCA and AcomA with a variation of the unilateral A1 segment, 41/43), complete recanalization occurred in 23 patients (27.4%), and it was significantly more likely to occur in PcomA aneurysms with fPCA (39.1%) than in AcomA aneurysms with a variation of the unilateral A1 segment (16.3%). Stent-assisted coil embolization (SACE) has been shown to reduce recanalization (OR =0.092, 95% CI: 0.011 to 0.790, P=0.03). Additionally, variant types and the normal type (non-fetal, 106, and bilateral A1 symmetry, 24) have different odds ratios (OR) of recanalization (P=0.04), and the OR of the variant subtypes was significant, unlike the normal type (P=0.49). CONCLUSIONS: This study suggests that PcomA aneurysms with fPCA are more likely to recanalize than AcomA aneurysms with a variation of the unilateral A1 segment.

We investigated lipidomic features from healthy controls (HCs), patients with unruptured cerebral aneurysms (UCAs) and ruptured CAs (RCAs) to analyze their lipidomic profiles and identify a lipid signature associated with CAs. Patients (n = 540) were enrolled from two centers. We identified significantly altered plasma lipids in 2 cohort with the total lipid intensity decreasing from HC to UCA to RCA. Triglycerides comprised the distinct profile of lipids in CAs. A four-lipid signatures showed good calibration and diagnostic prediction for CA vs. HC and UCA vs. RCA, but independent discriminate CA from HC, UCA from RCA, and RCA (RI and RII) or UCA (UI and UII) subtypes, in training and validation cohorts. Comprehensive lipidomic profiles identified decreased lipids as a prominent feature of CA development, and a four-lipid signature could not only better diagnose and predict UCAs/RCAs from HCs, but also predicted patients subtypes with severe RCA or high-risk UCA.

Mg-based stent is a promising candidate of the next generation fully degradable vascular stents. The latest progress includes the CE approval of the Magmaris ® WE43 based drug eluting stent. However, so far, the long term (more than 1 year implantation) in vivo degradation and the physiological effects caused by the degradation products were still unclear. In this study, a 20 month observation was carried out after the bare Mg-Nd-Zn-Zr (abbr. JDBM) stent prototype was implanted into the common carotid artery of New Zealand white rabbit in order to evaluate its safety, efficacy and especially degradation behavior. The degradation of the main second phase Mg12Nd was also studied. Results showed that the bare JDBM stent had good safety and efficacy with a complete re-endothelialization within 28 days. The JDBM stent struts were mostly replaced in situ by degradation products in 4 month. The important finding was that the volume and Ca concentration of the degradation products decreased in the long term, eliminating the clinicians’ concern of possible vessel calcification. In addition, the alloying elements Mg and Zn in the stent could be safely metabolized as continuous enrichment in any of the main organs were not detected although Nd and Zr showed an abrupt increase in spleen and liver after 1 month implantation. Collectively, the long term in vivo results showed the rapid re-endothelialization of JDBM stent and the long term safety of the degradation products, indicating its great potential as the backbone of the fully degradable vascular stent. Statement of significance Mg-based stent is a promising candidate of the next generation fully degradable stents, especially after the recent market launch of one of its kind (Magmaris). However the fundamental question about the long term degradation and metabolic mechanism of Mg-based stent and its degradation products remain unanswered. We implanted our patented Mg-Nd-Zn-Zr bare stent into the common carotid artery of rabbits and conducted a 20 months observation. We found that the Ca containing degradation products could be further degraded in vivo. All the alloying elements showed no continuous enrichment in the main organs of rabbits. These findings eliminate the clinicians’ concern of possible vessel calcification and element enrichment after the implantation of Mg alloy based stents to some extent.

The high temperature and pressure of the hot-pressing process of layered ferromagnetic/ferroelectric (FM/FE) composites inevitably give rise to magneto-electro-elastic (MEE) interfacial regions, where defects such as cracks often aggregate and definitely affect the performance of the composite. Fracture analysis is performed on an MEE interfacial region between an FM layer and an FE layer by the methods of Fourier integral transform and Cauchy singular integral equations. After the numerical computation is verified by the exact solution in a special case and the numerical solutions in existing literature, numerical results of MSERR (mechanical strain energy release rate) and COD (crack opening displacement) are provided to discuss the fracture behavior. The effect of FE volume fraction of the interfacial region on the fracture behavior is demonstrated from three different perspectives. Both material stiffness and constraint effect are used to explain the physical mechanisms. The obtained results may serve as guidelines for the anti-fracture design of FM/FE multiferroic composites. Because the existence of such MEE interfacial regions has been scarcely considered by existing papers, the main novelty of the present work is the incorporation of the MEE interfacial region into the mechanical model of the FM/FE composite.

Magnetic resonance angiography (MRA) is an important diagnosis method for the detection of intracranial aneurysms (IAs), but it is not useful for differentiating between IA and infundibular dilatation (ID) in patients in whom imaging shows an intracranial protrusion with a branch artery at its top. The objective of this study was to introduce a new approach—measurement of the outflow angle (OA)—for differentiating between IA and ID in such cases. The study included 7 patients with a total of 9 protrusions. The protrusions were separately reviewed on MRA and DSA images. We first diagnosed the protrusions using OA approach. An OA ≥90° was considered indicative of an IA and an OA

Yi-Feng Gu,1 Qing-Hua Tian,1 Yong-Dong Li,1 Chun-Gen Wu,1 Yan Su,2 Hong-Mei Song,1 Cheng-Jian He,1 Dong Chen,2 1Institute of Diagnostic and Interventional Radiology, 2Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, People’s Republic of China Objective: The aim of this study was to compare the efficacy of percutaneous vertebroplasty (PVP) and interventional tumor removal (ITR), with PVP alone for malignant vertebral compression fractures and/or spinal metastatic tumor with epidural involvement. Patients and methods: A total of 124 patients were selected for PVP and ITR (n = 71, group A) and PVP alone (n = 53, group B). A 14G needle and guide wire were inserted into the vertebral body, followed by sequential dilatation of the tract until the last cannula reached the anterior portion of the pedicle. Tumors were then ablated with a radiofrequency probe. ITR was performed with marrow nucleus rongeurs, and then cement was injected into the extirpated vertebra. Outcomes were collected preoperatively and at 1, 3 and 6months and every subsequent 6months. Results: The rates of pain relief and increased mobility at the last follow-up were higher in group A than those in group B (P < 0.05). There were significant differences in visual analog scale (VAS) score and Oswestry disability index (ODI) score at 1, 3 and 6months, 1year and >1year in group A than in group B (P < 0.05). The rates of paraplegia recovery and vertebral stability in group A were higher than those in group B (P < 0.05). Conclusion: PVP and ITR proved to be an effective approach for patients with malignant vertebral compression fractures and/or spinal metastatic tumor and provided distinct advantages in pain relief, function recovery and vertebral stability that are comparable to that obtained with PVP alone. Keywords: percutaneous vertebroplasty, pain, malignant spinal tumor, removal, metastasis

The ability to diagnose sidewall cerebral aneurysms (SCAs) on an angle measurement basis may be useful in clinical practice. A study was undertaken to evaluate the effect of an outflow angle (OA)-assisted approach.MR angiography (MRA) images of 438 patients with suspected SCAs and other cerebrovascular diseases were separately evaluated using the subjective approach and the OA approach. The approaches were then exchanged for confirmation of unclear cases. An OA of ≥90° was considered to represent SCA positivity. The accuracy, sensitivity, and specificity of the OA-assisted approach were determined using patient-based, aneurysm-based, and size-based evaluations.Digital subtraction angiography (DSA) detected 301 SCAs in 267 patients and no SCAs in 171. An OA of ≥90° was observed for 271 aneurysms in 244 patients (true positives); the OA approach misinterpreted OA as90° for 29 aneurysms in 29 patients (false negatives) and missed one aneurysm. The subjective approach detected 309 SCAs in 273 patients. This approach misdiagnosed 10 patients (false positives) and missed two aneurysms in two patients (false negatives). The OA-assisted approach detected 300 SCAs in 267 patients and no SCAs in 171, overlooking one aneurysm. Patient-based evaluation yielded high accuracy, sensitivity, specificity, and positive and negative predictive values for the OA-assisted approach.The OA-assisted approach for SCA diagnosis effectively reduced the false-positive rate obtained with the subjective approach with high accuracy, sensitivity, and specificity, suggesting that MRA based on this approach can be a reliable alternative to DSA in SCA screening and diagnosis.

ObjectiveTo evaluate whether the aneurysm outflow angle (OA) at MR angiography (MRA) might serve as discriminant for accurate diagnosis of, and differentiation between, small sidewall cerebral aneurysms (SCAs) and infundibula.MethodsBetween June 2007 and July 2015, 426 consecutive patients with SCAs completed both an MRA and DSA examination. Of these, 156 patients with small SCAs and 52 patients with infundibula were included in this study. A patient with an OA ≥90° was defined as having a SCA, while those with OA ResultsDSA identified 172 SCAs in 156 patients and 55 infundibula in 52 patients. The average OA on MRA was 102.96°±13.36° (range 60°–151°) in 172 SCAs of 156 patients. An OA of ≥90° was seen for 159 (92.4%) small SCAs in 147 patients, while an OA of ConclusionsThe OA at MRA could serve as discriminant for accurate diagnosis of, and differentiation between, small SCAs and infundibula.

To evaluate the diagnostic accuracy of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography at 3.0 T in the detection of small cerebral aneurysms.The institutional review board approved the study protocol, and patients or qualifying family members provided informed consent. A total of 403 consecutive patients undergoing 3D TOF MR angiography and digital subtraction angiography (DSA) were prospectively enrolled. Small aneurysms were those 5 mm in diameter or smaller. DSA served as the reference standard. Three observers were blinded to clinical and DSA results, and they independently analyzed all 3D TOF MR angiographic data sets. Interobserver agreement was expressed in terms of Cohen κ value for categorical variables. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3D TOF MR angiography in the detection of cerebral aneurysms were determined by using patient-, aneurysm-, and location-based evaluations.Of 403 patients, 273 aneurysms were detected with DSA in 230 patients. Patient-based evaluation with 3D TOF MR angiography at 3.0 T yielded an accuracy of 96%-97%, a sensitivity of 98.2%-98.7%, a specificity of 93.2% -94.8%, a PPV of 94.9%-96.2%, and an NPV of 97.6%-98.2% in the detection of cerebral aneurysms. Aneurysm-based evaluation yielded an accuracy of 96.4%-97.3%, a sensitivity of 98.5%-98.9%, a specificity of 93.2%-94.9%, a PPV of 95.7%-96.8%, and an NPV of 97.6%-98.2%. Aneurysm-location evaluations yielded similar results.Three-dimensional TOF MR angiography is a noninvasive method that shows promising diagnostic accuracy in the detection of small cerebral aneurysms.

The purpose of this study was to determine the safety and efficacy of percutaneous vertebroplasty and interventional tumor removal in the management of metastatic spinal tumors and malignant vertebral compression fractures.Thirty-one patients with metastatic spinal tumors and malignant vertebral compression fractures were treated with percutaneous vertebroplasty and interventional tumor removal. Insertion of a 14-gauge needle and guidewire into the vertebral body was followed by sequential dilation of the track with working cannulae until the last cannula reached the anterior portions of the pedicle. Interventional tumor removal was performed with marrow nucleus rongeurs, and 5-10 mL of cement was injected into the treated vertebra. Outcome data (visual analog scale score, Oswestry disability index score, and Karnofsky performance scale score) were collected preoperatively; 1 week and 1, 3, and 6 months after the procedure; and every 6 months thereafter until death.The overall clinical assessment at the last follow-up evaluation showed that pain was completely resolved in 23 patients, decreased in six patients, and unimproved in two patients, yielding a pain relief rate of 94%. The average preoperative visual analog scale score was 7.2, which decreased to 2.4 at 1 month, 1.9 at 6 months, and 1.6 at 1 year and was maintained at 1.3 at the follow-up evaluations performed after more than 1 year. Statistically significant improvement in Oswestry disability index and Karnofsky performance scale scores was also seen between the preoperative evaluation and every follow-up assessment postoperatively (p0.001).Percutaneous vertebroplasty and interventional tumor removal are safe, effective, and minimally invasive palliative therapies for reducing pain and improving function in patients with metastatic spinal tumors and malignant vertebral compression fractures.

The present work investigates the problem of a cylindrical interface crack in a bi-layered tubular composite of finite thickness under torsion. Theoretical derivation is performed by the methods of Fourier integral transform and Cauchy singular integral equations. Numerical results of the stress intensity factor are discussed to reveal the coupled effects of the geometrical and physical parameters on the interfacial fracture behavior. The preferred values for the thickness ratio and the stiffness ratio are obtained, which provide necessary reference to the optimal design in engineering. To prevent interfacial fracture, it is better for the two layers to have identical thickness, and under this condition a stiffer inner layer plus a softer outer layer is a preferred choice. However, if the outer layer is enough thin, a softer inner layer plus a stiffer outer layer becomes optimal instead.

To evaluate treatment decision-making based on susceptibility-weighted imaging (SWI) in patients with hemorrhage after thrombolysis.One hundred and forty-six patients without intracranial hemorrhage on CT after receiving recombinant tissue plasminogen activator (rt-PA) were allocated to two groups: antiplatelets (n=72), who received antiplatelet therapy 24h after rt-PA for 10 days; and non-antiplatelets (n=74), who received no antiplatelet therapy. Twenty-two patients with SWI-detected microbleeds (MBs) or hemorrhagic transformation (HT) in the antiplatelets group (Group A) and 28 with MB or HT in the non-antiplatelets group (Group B) were included in this study.Sixteen patients had MB and six HT in Group A; 18 had MB, six HT, and four parenchymal hemorrhage (PH) in Group B. National Institutes of Health Stroke Scale (NIHSS) scores at 7 and 14 days and the Modified Rankin Scale (mRS) at 90 days post-rt-PA were significantly lower in Group B than in Group A, duration of hospitalization was significantly shorter, and the favorable outcome rate was higher at 90 days (P0.05). There were no other significant differences. SWI evaluation at 14 days revealed eight patients with MB, 11 HT, and three PH in Group A; in Group B, 16 had MB, five HT, and one PH, with resolution of hemorrhage in six patients.Treatment decision-making based on SWI in acute stroke after thrombolysis was validated by the significantly reduced NIHSS score after 7/14 days, improved outcome, and reduced mRS in hemorrhage patients without antiplatelet therapy.

Magnesium alloy covered stents have rarely been used in the common carotid artery (CCA). We evaluated the long-term efficacy of magnesium alloy covered stents in a lateral aneurysm model in rabbit CCA. Magnesium alloy covered stents (group A, n = 7) or Willis covered stents (group B, n = 5) were inserted in 12 New Zealand White rabbits and they were followed up for 12 months. The long-term feasibility for aneurysm occlusion was studied through angiograms; the changes in vessel area and lumen area were assessed with IVUS. Complete aneurysmal occlusion was achieved in all aneurysms. Angiography showed that the diameter of the stented CCA in group A at 6 and 12 months was significantly greater than the diameter immediately after stent placement. On intravascular ultrasound (IVUS) examination, the mean lumen area of the stented CCA in group A was significantly greater at 6 and 12 months than that immediately after stent placement; the mean lumen area was also significantly greater in group A than in group B at the same time points. The magnesium alloy covered stents proved to be an effective approach for occlusion of lateral aneurysm in the rabbit CCA; it provides distinct advantages that are comparable to that obtained with the Willis covered stent.

Background Endovascular treatment of complex traumatic direct carotid-cavernous fistulas (TDCCFs) is a challenge. Objective To evaluate the long-term efficacy of the Willis covered stent in endovascular treatment of complex TDCCFs, focusing on reconstruction and preservation of the internal carotid artery. Methods During the past 8 years, 25 patients with 27 TDCCFs who previously had unsuccessful treatment of fistulas with detachable balloons received endovascular treatment with Willis covered stents. The efficacy, complications, in-stent stenosis, angiographic, and clinical follow-up results were evaluated retrospectively between 6 and 88 months (mean, 43.8 months) after the stent placement. Results The technical success rate of stenting placement was 100%. Forty-four Willis covered stents were implanted into the target artery of 27 TDCCFs. Complete exclusion was achieved in 16 patients with 17 TDCCFs immediately after the stent placement, with transient endoleaks in 10 TDCCFs. Redilation was performed in 6 TDCCFs, and additional stents were implanted in the other 4 TDCCFs for endoleak exclusion. The initial angiographic results showed complete exclusion of fistulas with preservation of the internal carotid artery in 24 patients with 26 TDCCFs. One patient in whom complete occlusion initially was achieved subsequently experienced a delayed endoleak, which required placement of an additional stent. The angiographic follow-up results (mean, 30.3 months) demonstrated complete exclusion in all 27 TDCCFs, with patency of internal carotid artery in 23 patients. The clinical follow-up demonstrated a full recovery in 23 patients and improvement in 2 patients. Conclusion The use of Willis covered stents was confirmed to be effective, safe, and a curative approach for endovascular treatment of complex TDCCFs and internal carotid artery reconstruction. Abbreviations DB, detachable balloonEVT, endovascular treatmentICA, internal carotid arteryn-BCA, N-butyl cyanoacrylateTDCCF, traumatic direct carotid-cavernous fistula.

To analyze the outcomes of a magnesium alloy covered stent (MACS) for a lateral aneurysm model in common carotid artery (CCA).In 32 rabbits, a MACS (group A, n = 17) or a Willis covered stent (WCS; group B, n = 15) was inserted and the rabbits were sacrificed 1, 3, 6, or 12 months after stenting. Angiography and intravascular ultrasound (IVUS) were performed at 3, 6, and 12 months. Scanning electron microscopy was performed for six stents in each group at 1, 3, and 6 months, and histopathology and histomorphology were conducted at 3 (n = 4), 6 (n = 4), and 12 (n = 12) months.Final angiography showed complete occlusion of the aneurysms in 12 cases. IVUS at 6 and 12 months revealed a significant increase in mean lumen area of the stented CCA in group A and also showed greater mean lumen area in group A than in group B. The endothelialization process was quicker in group A than in group B.MACS is effective for occlusion of lateral aneurysms and is superior to WCS in growth of the stented CCA and endothelialization. Further work is needed to make this device available for human use.• The MACS is an effective approach for occlusion of a lateral aneurysm. • IVUS showed that the CCA could grow following degradation of the MACS. • The lumen area of the stented CCA was excellent in MACS. • HE staining displayed the degradation of the magnesium alloy stent. • Combination of IVUS and DSA were applied in this study.

The authors investigated the effectiveness of high-resolution magnetic resonance angiography (MRA) using a single-artery highlighting technique for the accurate diagnosis of intracranial aneurysms at 3.0 T in a large cohort of patients with suspected intracranial aneurysms against the current gold standard, i.e. cerebral angiography.A total of 307 patients with suspected aneurysms were referred for three-dimensional time-of-flight MRA (3D-TOF-MRA) prior to digital subtraction angiography (DSA). We summarised patient-based, aneurysm-based and vessel-based diagnostic performance parameters, namely, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detecting intracranial aneurysms with 3D-TOF-MRA. Interobserver agreement was calculated with the kappa (κ) statistic.Patient-based accuracy was 98.1%, sensitivity 99.5%, specificity 95.3%, PPV 97.6% and NPV 99% according to observer A; and 97.7%, 99.5%, 94.3%, 97.1% and 99%, respectively, according to observer B. Aneurysmbased accuracy was 98.3%, sensitivity 99.6%, specificity 95.2%, PPV 98.1% and NPV 99% according to observer A, and 98.0%, 99.6%, 94.3%, 97.7% and 99%, respectively, according to observer B. Vessel-based accuracy was 99.0%, sensitivity 99.6%, specificity 98.7%, PPV 97.8%, and NPV 99.7% according to observer A, and 98.9%, 99.6%, 98.5%, 97.3%, and 99.7%, respectively, according to observer B. Interobserver reading differences were not significant. The interobserver agreement was good, with a kappa (κ) value of 0.931 for patient-based evaluation, 0.934 for aneurysmbased evaluation and 0.953 for vessel-based evaluation.Our results demonstrate the effectiveness of high-resolution MRA using a single-artery-highlighting technique for accurate diagnosis of intracranial aneurysms in a large cohort of patients with suspected aneurysms.

To evaluate the clinical value of unenhanced magnetic resonance angiography (MRA) at 3.0 T for the diagnosis and therapeutic planning of patients with subarachnoid haemorrhage (SAH).A total of 165 patients with SAH were referred for three-dimensional time-of-flight MRA (3D-TOF-MRA) before digital subtraction angiography (DSA). For each aneurysm, 3D-TOF-MRA was used to determine whether the aneurysm was suitable for coil placement with or without balloon/stent-assisted coiling, surgical clipping or conservative treatment. Treatment planning with 3D-TOF-MRA was compared with actual treatment decisions or treatment that had been carried out in each aneurysm decided using DSA.The aneurysm-based evaluation yielded accuracy of 96.9%, sensitivity of 97.6%, specificity of 93.1%, positive predictive value (PPV) of 98.8% and negative predictive value (NPV) of 87.1%, in the detection of intracranial aneurysms. Treatment planning could be correctly made on the basis of aneurysm anatomy and working view by volume rendering (VR) 3D-TOF-MRA with accuracy, sensitivity, specificity, PPV and NPV of 94.9%, 94.0%, 100%, 100% and 74.4%, respectively, on a per aneurysm-based evaluation.VR 3D-TOF-MRA offers high diagnostic accuracy in the detection of ruptured intracranial aneurysms, and appears to be an effective treatment planning tool for most patients with SAH.VR 3D-TOF-MRA offers high diagnostic accuracy for detecting ruptured intracranial aneurysms. • VR 3D-TOF-MRA helps treatment planning for patients with subarachnoid haemorrhage. • 3D-TOF-MRA is non-invasive and avoids using ionising radiation or contrast agents.

To explore whether human albumin (Alb) administration prior to thrombolysis with recombinant tissue plasminogen activator (rt-PA) can eliminate brain damage induced by this treatment given after the effective and safe window of 3h after stroke onset. Rats were subjected to embolic stroke by unilateral embolic middle cerebral artery occlusion (MCAO). Three or six hours after the onset of stroke, rats were administered intravenously with saline (control), rt-PA (thrombolysis) or rt-PA+Alb (additional Alb 3h after MCAO, combination). Cerebral blood flow, infarct volume, space-occupying effect and blood brain barrier (BBB) leakage of gadopentetate dimeglumine (Gd-DTPA) were assessed dynamically by magnetic resonance imaging (MRI) at 24h, 7 and 14days after treatment. BBB leakage of both fluoro-isothiocyanate dextran (FITC-dextran) and erythrocytes was also evaluated 14days after treatment. The space-occupying effect in the combination group at 7days after treatment declined significantly compared with that at 24h after treatment (P

In the present work, we investigate the problem of multiple cracks on the interface between a piezoelectric layer and an orthotropic substrate. The method of dislocation simulation and singular integral equation are used to solve the crack problem. The theoretical derivation is verified by the classical result in a special case. Numerical results of the stress intensity factor are obtained, and thereby the effects of geometrical parameters and material orthotropy are surveyed. The optimal stiffness ratio of the orthotropic substrate is suggested for the purpose of interfacial fracture prevention, which is significant for the design and assessment of such a kind of smart structures.

Background To evaluate the initial clinical safety and feasibility of anticoagulation using warfarin for Budd–Chiari syndrome (BCS) with chronic inferior vena cava (IVC) thrombosis. Methods Between October 2005 and June 2009, a total of 16 consecutive BCS patients with chronic IVC thrombosis were treated with warfarin. Warfarin was administered orally at 2.5 mg/d for approximately 3-12 months. Transluminal balloon dilatation of the IVC with a 30-mm balloon catheter was applied for the patients with complete resolution of the thrombus. Data relating to the technical success, angiographic results, complications, and final clinical outcome were collected retrospectively and follow-ups were performed at 1, 3, 6, and 12 months after the stent placement, and annually thereafter. Results Warfarin was successfully used for anticoagulation in all patients without any complications. Patients were followed up as outpatients for 6.43 ± 2.19 months, and in 14 cases, complete disappearance of the thrombosis was achieved with successful treatment by balloon dilation. In two patients with partial resolution of the thrombosis, Z-stent placement was initiated to compress the thrombus to prevent migration of the thrombosis, followed by dilation of the IVC. During the follow-up for 20.94 ± 10.31 months after the procedure, all the IVC remained patent without complications or pulmonary embolus, and all patients were alive with resolution of symptoms at the time of this study. Conclusions The use of warfarin for anticoagulation proved to be simple, safe, and feasible for BCS with chronic IVC thrombosis.

Purpose To evaluate the efficacy of the Willis covered stent in the treatment of traumatic pseudoaneurysms of the internal carotid artery (ICA). Materials Thirty-eight patients with traumatic head and neck injury underwent angiography. We evaluated 14 delayed pseudoaneurysms in 13 patients who underwent angiography after treatment with the Willis covered stent. Prospective data on the technical success, initial and final angiographic results, mortality, morbidity, and final clinical outcome were analyzed immediately after the procedure, at the time of discharge from the hospital, at 3 months, 6 months, and 12 months after the procedures, and yearly thereafter. Results The Willis covered stent placement was successful in all 14 pseudoaneurysms. The initial angiographic results showed complete exclusion in 9 patients with 10 aneurysms (71.4% [95% confidence interval {CI}: 44-98%]) and incomplete exclusion in 4 patients. The angiographic follow-up (mean, 15 months [95% CI: 9-20 months]; range, 3-36 months) findings exhibited a complete exclusion in 12 patients with 13 aneurysms (92.9% [95% CI: 77-108%]) and an incomplete exclusion in 1 patient and maintained patency of the ICA in all patients. The clinical follow-up (mean, 20 months [95% CI: 14-27 months]) findings demonstrated full recovery (11 patients), symptom improvement (1 patient), or no change in the symptoms (1 patient). No procedure-related complications or deaths occurred during follow-up. Conclusion Treatment with the Willis covered stent provides a viable approach for patients with traumatic pseudoaneurysms of the ICA, maintaining patency of the ICA and thus leading to excellent clinical results. An expanded clinical experiences and a larger sample are needed.

Objectif Evaluer la securite clinique initiale et la faisabilite d'une anticoagulation par warfarine pour syndrome de Budd–Chiari (SBC) en cas de thrombose chronique de la veine cave inferieure (VCI). Methodes Entre octobre 2005 et juin 2009, un total de 16 patients consecutifs atteints de SBC ayant une thrombose chronique de la VCI a ete traite par de la warfarine. La warfarine a ete administree oralement a une dose de 2,5 mg/j. pendant approximativement trois a 12 mois. Une dilatation transluminale a ballonnet de la VCI a l'aide d'un ballon de 30 mm a ete effectuee chez les patients ayant une disparition complete du thrombus. Les donnees concernant le succes technique, les resultats angiographiques, les complications et les resultats cliniques finaux ont ete collectes retrospectivement et un suivi a ete obtenu a un, trois, 6 et 12 mois apres la mise en place du stent puis chaque annee par la suite. Resultats La warfarine a ete une anticoagulation efficace chez tous les patients, sans aucune complication. Les patients etaient suivis en externe pendant une duree moyenne de 6,43 ± 2,19 mois et dans 14 cas, une disparition complete de la thrombose a ete obtenue puis completee avec succes par une dilatation a ballonnet. Chez deux patients ayant une resolution partielle de la thrombose, la mise en place d'un Z-stent a ete utilisee initialement pour comprimer le thrombus afin de prevenir la migration de la thrombose, puis la dilatation de la VCI a ete effectuee. Au cours d'un suivi de 20,94 ± 10,31 mois suivant la procedure, toutes les VCI sont restees permeables, sans complication ou embolie pulmonaire et tous les patients etaient vivants et asymptomatiques au moment de l'etude. Conclusion L'utilisation d'une anticoagulation par warfarine s'est averee etre simple, sure et faisable en cas de SBC avec thrombose chronique de la VCI.

Object Placement of covered stents has emerged as a promising therapeutic option for cerebrovascular diseases. However, the medium- and long-term efficacy and safety of covered stents in the treatment of these diseases remain unclear. The purpose of this study was to evaluate the medium-term clinical and angiographic outcomes of covered stent placement for the treatment of intracranial aneurysms. Methods The authors' institutional review board approved the study. Thirty-four patients (13 females and 21 males; mean age 41.9 years) with 38 intracranial aneurysms were treated with the Willis covered stent. Clinical and angiographic follow-up were performed at 3 months, at 6–12 months, and annually thereafter. The initial procedural and follow-up outcomes were collected and analyzed retrospectively. Results Forty-two covered stents were successfully implanted into the target artery in 33 patients with 37 aneurysms, and 1 covered stent navigation failed in 1 patient. A complete aneurysm exclusion was initially achieved in 24 patients with 28 aneurysms, and a minor endoleak occurred in 9 patients with 9 aneurysms. Postoperatively, 2 patients died of complications related to the procedure. Angiographic and clinical follow-up data are available in 30 patients. The angiographic follow-up (17.5 ± 9.4 months [mean ± SD]) exhibited complete occlusion in 28 patients with 31 aneurysms, and incomplete occlusion in 2 aneurysms, with an asymptomatic in-stent stenosis in 3 patients (10%). The clinical follow-up (26.7 ± 13 months [mean ± SD]) demonstrated that 16 patients (53.3%) experienced a full recovery, and 14 patients (46.7%) improved. No aneurysm rupture, thromboembolic events, or neurological deficits resulting from closure of a perforating vessel by covered stent placement occurred. Conclusions Endovascular reconstruction with the Willis covered stent represents a safe, durable, and curative treatment option for selected intracranial aneurysms, yielding an excellent medium-term patency of the parent artery and excellent clinical outcomes.

The purpose of this article is to compare the efficacy of self-expanding metallic stents and pneumatic dilation for the long-term clinical treatment of achalasia.Patients diagnosed with achalasia (n = 120) were allocated for treatment with pneumatic dilation (n = 30; group A) or a temporary self-expanding metallic stent with a diameter of 20 mm (n = 30; group B), 25 mm (n = 30; group C), or 30 mm (n = 30; group D). Data on clinical symptoms, complications, and long-term clinical outcomes were collected, and follow-up was performed at 6 months and at 1, 3-5, 5-8, 8-10, and more than 10 years after surgery.Pneumatic dilation and stent placement were technically successful in all patients. The follow-up at more than 10 years revealed that the clinical remission rate in group D (83.3%) was higher than that in groups A (0%), B (0%), and C (28.6%), and the overall cumulative clinical failure rate in group D (13%) was lower than that in groups A (76.7%), B (53.3%), and C (26.7%). Patients in group D exhibited reduced dysphagia scores and lower esophageal sphincter pressures and had normal levels of barium height and width during the follow-up periods, whereas these markers increased with time in the other groups. The duration of primary patency in group D was also longer than that in groups A, B, and C.A temporary self-expanding metallic stent with a diameter of 30 mm has superior clinical efficacy for the treatment of achalasia compared with pneumatic dilation or self-expanding metallic stents with diameters of 20 or 25 mm.

To evaluate the feasibility of metallic stent placement and the formation of granulation tissue caused by stent placement in a rat urethral model.A bare self-expanding metallic stent was inserted in the urethra under fluoroscopic guidance in 20 male Sprague-Dawley rats. Ten rats were euthanized at 4 weeks (group A), and the other 10 were euthanized at 8 weeks after stent placement (group B). Stenosis diameter, number of epithelial layers, degree of inflammatory cell infiltration, thickness of submucosal fibrosis, and percentage of granulation tissue area were assessed.Stent placement was technically successful in all rats. Urethrograms showed perforation in three rats, partial migration in three, and stone formation in four. Granulation tissue formation was observed in all rats at the stent-implanted urethra, and the average percentage of granulation tissue area accounted for 41% and 45% of the original urethral lumen area in groups A and B, respectively. Urethrograms and urethral specimens showed significantly less stenosis diameter, less thickness of submucosal fibrosis, and lower percentage of granulation tissue area in the proximal urethra than in the distal urethra in both groups (P.05). Histologic results demonstrated significantly fewer epithelial layers in group B compared with group A (P = .028).Placement of a self-expandable metallic stent proved to be feasible in the rat urethra and an efficient approach to stimulate granulation tissue formation as a potential model for reproducing the mechanisms of restenosis.

Whether an infundibular dilation (ID) is an anatomical variant or a pre-aneurysm has not been clearly determined. The aim of the present study was to evaluate the anatomical change of IDs by use of three-dimensional rotational angiography (3DRA) with volume rendering (VR). One-hundred thirty-eight patients with known or suspected aneurysms, treated consecutively, underwent both two-dimensional digital subtraction angiography (2DDSA) and 3DRA with VR. Two readers evaluated the IDs or aneurysms blindly, using 2DDSA and 3DRA, according to the same diagnostic criteria. A 5-point scale of observer confidence was used to determine the presence of IDs or aneurysms. For 3DRA with VR, the relationship between IDs and aneurysms was classified as one of the three types: type I, protrusion or bulge from side wall of IDs; type II, aneurysms involving or enclosing IDs; or type III, aneurysms and IDs coexisting near each other but with some distance between them. The number of IDs found by 2DDSA and 3DRA with VR was 41 and 48, respectively. Five anterior choroidal arteries and two posterior communicating arteries IDs were missed by 2DDSA. According to 3DRA with VR, there were five IDs of type I, nine of type II, and 22 of type III. The 3DRA with VR appears superior to 2DRA for both diagnosing IDs and displaying the anatomical relationship between IDs and aneurysms. The findings also suggest that some IDs might progress to aneurysms or become a part of them, which should be carefully evaluated prior to operation.

For the first time, real fundamental solutions are proposed for in-plane magnetoelectroelastic governing equations. Dislocation simulation method is used to derive singular integral equations for collinear unequal crack series under mode I loadings. Special cases of a single crack and two collinear equal cracks are used to validate the proposed solution. The effects of crack space, crack length and magnetic/electric loading are discussed. Real fundamental solutions have an advantage over complex fundamental solutions, because real analyses are more straightforward than complex analyses. Moreover, the model of collinear unequal cracks is more practical than that of collinear equal cracks.

The present article analyzes the two-dimensional antiplane fracture problem for the interface in a semicircular cylindrical guide rail consisting of a wear-proof layer and an elastic substrate. Fracture analysis is performed by the methods of infinite series and singular integral equation. The effects of interface end, structural thickness, and stiffness ratio are discussed. In contrast with internal cracking, the end fracture is specially considered, yielding the way to reduce the stress intensity factor of an interface-end crack. These theoretical results may provide references for antifracture optimal designs of guide rails in structures and machines such as telescopic arms of cranes.

Purpose To prospectively evaluate the safety and clinical efficacy of a newly designed self-expandable metallic stent (SEMS) in the treatment of patients with acute malignant colorectal obstruction. Methods Between April 2001 and October 2007, 52 patients with acute malignant colorectal obstruction were treated with a new designed SEMS as an investigational bridge to surgery. Patients were prospectively followed and relevant data collection was collected, including details regarding technique, clinical symptoms, complications, need for elective surgery, and overall survival. Results Stent placement was technically successful in all but two patients (due to complete obstruction) with no procedure-related complications. Complications included stent migration ( n = 4), anal pain ( n = 2) and stool impaction ( n = 1). Clinical success was achieved in 49 (98%) of 50 patients with resolution of bowel obstruction within 2 days of stent placement. In one patient with stool impaction 2 days after stent placement, endoscopic disimpaction was successfully performed. An elective one-stage surgical procedure was performed in all 50 patients who successfully received a SEMS as a bridge to surgery within a mean of 8 ± 2 days (range: 4–11 days) after stent placement. Mean follow-up time was 36 ± 12 months (range 3–70 months), and all patients remained alive at the time of this report. Conclusion The newly designed SEMS placement as a bridge to surgery was a safe and effective intervention for colonic decompression in patients with acute malignant colorectal obstruction and allowed a high proportion of patients to be successfully proceeded to elective surgery.

The magnetostrictive fracture model is established for a cylindrical multiferroic composite loaded by magnetic field and mechanical constraining traction. Fracture analysis is performed by the methods of Cauchy singular integral equation and Lobatto–Chybeshev collocation. Numerical results of the stress intensity factor (SIF) are obtained and the computational accuracy is demonstrated. The effects of the thickness ratio, the total thickness and the inner radius on the SIF are discussed, which provides practical references for geometrical optimization of the structure. The effect of material stiffness on the SIF is specially analyzed and the influences of piezoelectric stiffening and piezomagnetic stiffening are thereby compared.

A 53-year-old man presented with severe cough and pulmonary infection 1 month after receiving a second mushroom-shaped covered metallic stent for occluding a gastrobronchial fistula (GBF). The fistula was caused by an esophageal stent that was placed 4 months after esophagogastrectomy for the treatment of gastroesophageal stenosis. Six months before the patient was admitted to our hospital, he had undergone esophagogastrectomy for esophageal cancer; a thoracic anastomosis was created, and a wide gastric tube was inserted through a left thoracotomy. Multislice computed tomography, gastroscopy, and esophagography with contrast medium revealed a fistulous communication between the right posterior wall of the upper residual stomach and the dorsal segment of the left lower lobe bronchus after the removal of stents. A short covered stent and a partially covered integrated inverted Y-shaped metallic stent were implanted into the bronchi, and subsequently, the fistula was closed completely. The patient was discharged 2 weeks after stent placement; at the time of discharge, he showed full recovery and complete resolution of the symptoms related to GBF.

The purpose of the present work is to study the fracture behavior of the arc-shaped interface in a cylindrical non-homogeneous magnetoelectroelastic structure. Fracture analysis is performed by the method of Cauchy singular integral equation. Parametric studies are conducted on the stress intensity factor, and practical guidelines are given for the optimization of fracture performance. (a) The ratio between the outer and inner radii should be at least 1.1. (b) A softer inner side plus a stiffer outer side is a good non-homogeneity design for the magnetoelectroelastic layer. (c) A soft central cylinder and a stiff outer magnetoelectroelastic layer constitute a good stiffness matching on the interface.

The purpose of this study was to compare, focusing on colonic perforation and stent migration, the clinical safety and efficacy of dual-design expandable colorectal stents with flared ends with those of stents with bent ends in the treatment of patients with malignant colorectal obstruction.A total of 122 patients with malignant colorectal obstruction underwent implantation of dual-design stents with flared (n = 69) or bent (n = 53) ends.Stent placement was technically successful in 116 of 122 patients (95.1%), 65 of 69 patients (94.2%) with flared-end stents and 51 of 53 patients (96.2%) with bent-end stents (p0.05). Clinical success was achieved within 2 days in 61 of 65 patients (93.8%) with bent-end stents and in 46 of 51 patients (90.2%) with flared-end stents (p0.05). Complications included seven cases of colonic perforation (6%), seven cases of stent migration (6%), three cases of tumor overgrowth (2.6%), four cases of severe rectal pain (3.4%), and four cases of bleeding (3.4%). There were no significant differences between the rates of colonic perforation and stent migration in the two groups (6.2% vs 5.9%), and the overall complication rates were similar (p0.05).Dual-design expandable colorectal stents with flared ends and those with bent ends are equally safe and effective, having similar perforation and migration rates.

The mechanical model is established for a piezoelectric sensor with a mode III permeable crack parallel to the imperfect interface. Fracture analysis is performed by the standard methods of Fourier transform and singular integral equation. Three conclusions are drawn: (a) the imperfect interface has a shielding effect on the crack parallel and very near to it; (b) the shielding effect depends on the structural stiffness and the distance between the crack and interface; (c) for the electrically permeable crack, mechanical imperfection has more remarkable shielding effect than dielectric imperfection does.

Micropolar elasticity theory links together the macro mechanical behavior and the micro geometrical scales and makes it possible to study the macro and micro fracture of micro-structural materials by classical methods. The present work aims at comparing the effects of micropolarity on the fracture parameters of a micro-crack and a macro-crack. Through Fourier integral transform, the problem of a mode-I crack in an infinite micropolar plane is reduced as a system of Cauchy singular integral equations, which are further solved numerically by the Lobatto–Chebyshev collocation method. Parametric studies on the numerical solutions of the force stress and couple stress intensity factors indicate that: the fracture behavior of the micropolar material depends on not only micropolar parameters but also the loading; when the force traction is applied, the micropolar material with a micro-crack behaves more softly than classical elastic materials, but the micropolar material with a macro-crack behaves more stiffly than the classical case. It is concluded that the micropolarity is beneficial to reducing the driving force of a micro-crack, but it may also enhance the driving force of a macro-crack meanwhile.

To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4–5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n = 4, 5.33%), chest pain (n = 28, 38.7%), reflux (n = 15, 20%), and bleeding (n = 9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1–3, 3–5, 5–8, 8–10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 ± 0.28 years (95% CI: 2.25–3.35) and 4.28 ± 0.40 years (95% CI: 3.51–5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate.

The mechanical model was established for the anti-plane fracture problem of a functionally graded coating–substrate system with a coating crack inclined to the weak/micro-discontinuous interface. The Cauchy singular integral equation for the crack was derived using Fourier integral transform, and the Lobatto–Chebyshev collocation method put up by Erdogan and Gupta was used to get its numerical solution. Finally, the effects of the weak/micro-discontinuity of the interface on SIFs were analyzed, the “affected regions” corresponding to the two crack tips have been obtained and their engineering significance was discussed. It was indicated that, for the crack tip in the corresponding “affected region”, to reduce the weak-discontinuity of the interface and to make the interface micro-discontinuous are the two effective ways to reduce the SIF, and the latter way always has more remarkable SIF-reduction effect. For the crack tip outside the “affected region”, its SIF is mainly influenced by material stiffness, and to prevent such a tip from growing toward the interface “softer coating and stiffer substrate” is a more advantageous combination than “stiffer coating and softer substrate”.

To evaluate the technical success and initial clinical safety and effectiveness of the use of a Y-shaped metallic stent for complex stenoses involving the carina.Thirty-five consecutive patients with complex tracheobronchial stenoses involving the carina were treated with an integrated self-expandable inverted Y-shaped metallic stent and delivery system. The Y-shaped metallic stents were placed in the tracheobronchial tree with fluoroscopic guidance. Technical success, clinical success, Hugh-Jones classification, and complications were assessed during follow-up.The delivery of the integrated self-expandable Y-shaped metallic stent in the carinal areas was technically successful and well-tolerated in all patients. Clinical success was achieved in 31 patients (89%) 1-7 days after stent placement; the procedure failed in four patients (11%). The improvement between pre- and postoperative Hugh-Jones classification grade was statistically significant (P.001). During follow-up (mean follow-up, 192 days+/-169), all stenoses were resolved, and general physical examination of the 31 patents showed improvement with no obvious dyspnea or bleeding. Twenty-one patients were healthy without evidence of dyspnea, and the remaining 14 patients died (mean survival, 189 days+/-172) at the time of this report. The mean and median survival periods were 217 days+/-30 and 215 days+/-108, respectively. The mean and median stent patency periods were 216 days+/-30 and 215 days+/-119, respectively.Deployment of an integrated, self-expandable inverted Y-shaped metallic stent with the delivery system was a safe and effective procedure for the treatment of complex tracheobronchial stenoses involving the carina.

A mechanical model was established for the antiplane dynamic fracture problem of a functionally graded coating–substrate structure with a coating crack perpendicular to the weak-discontinuous interface. The problem was reduced to a Cauchy singular integral equation by the methods of Laplace and Fourier integral transforms. Erdogan’s collocation method and the Laplace numerical inversion proposed by Miller and Guy were used to calculate the dynamic stress intensity factors. Three conclusions were drawn through parametric studies: (a) unlike the conclusion drawn for an interfacial crack, reducing the weak discontinuity of the interface will not necessarily decrease the dynamic stress intensity factor (DSIF) of the coating crack perpendicular to the interface; (b) increasing the stiffness of the substrate when that of the coating is fixed, or decreasing the stiffness of coating when that of the substrate is fixed, will be beneficial for the reduction of the DSIF of a coating crack perpendicular to the interface; and (c) the free surface has a greater influence on the DSIF than the interface does, and the effect of the interface on the DSIF is greater than that of the material stiffness in the crack-tip region.

The anti-plane impact fracture analysis was performed for a weak-discontinuous interface in a symmetrical functionally gradient composite strip. A new bi-parameter exponential function was introduced to simulate the continuous variation of material properties. Using Laplace and Fourier integral transforms, we reduced the problem to a dual integral equation and obtained asymptotic analytical solution of crack-tip stress field. Based on the numerical solution of the second kind of Fredholm integral equation transformed from the dual integral equation, the effects of the two non-homogeneity parameters on DSIF were discussed. It was indicated that the relative stiffness of the interface and the general stiffness of the whole structure are two important factors affecting the impact fracture behavior of the weak-discontinuous interface. The greater the relative stiffness of the interface is, the higher the value of the dynamic stress intensity factor will be. The greater the general stiffness of the whole structure is, the shorter the time for DSIF to arrive at the peak value and then to stabilize to the steady one. If the general stiffness of the whole structure is great enough, there will be an oscillation between the peak and steady values of DSIF.

Purpose Anterior approaches to the lumbosacral spine have become increasingly common in spine surgery, but transabdominal percutaneous lumbar discectomy (TPLD) is challenging. This study describes TPLD and evaluates safety and early clinical results in the management of L5–S1 disc herniation. Materials and Methods Between October 2001 and October 2006, 58 consecutive patients with L5–S1 disc herniations were treated with TPLD of the L5–S1 discs, and nine of the patients with L4–L5 disc herniations were treated with posterolateral percutaneous lumbar discectomy (PPLD) soon after TPLD. The patients were divided into two groups according the operator who performed the procedures. The patients were evaluated with a visual analog scale (VAS) and the Oswestry Disability Index (ODI) at 5 years of follow-up. Logistic regression was used to analyze significant risk factors for complications. Results Mean hospital stay was 6.38 days ± 8.48. VAS scores for leg pain and ODI scores showed significant improvement at last follow-up. All patients showed favorable results with no recurrent herniations. Major and minor complications occurred in eight (13.79%) and seven cases (12.06%), respectively, during and after the procedure. Major complications occurred in seven patients treated by operator A and one treated by operator B, a significant difference between operators ( P = .044). Multivariate analysis revealed that only bowel preparation remained a significant predictor of complications ( P = .040). Conclusion TPLD was a safe and effective procedure for the removal of disc herniations at the L5–S1 level when total bowel preparation was performed.

Purpose The purpose of this study was to evaluate the initial clinical efficacy of a retrieval stent filter for the management of Budd Chiari syndrome complicated with inferior vena cava thrombosis. Description The retrieval stent filter consists of two parts (ie, the filter and the Z-stent). The filter was composed of seven legs arranged in the shape of a cone with a retrieval hook at its apex. The filter and the Z-stent were connected with each other, and the retrieval of the stent filter was performed with an Amplatz gooseneck snare (MicroVena [White Bear Lake, MN]). Eight consecutive patients were treated with the stent filters. Evaluation The stent filter placement was technically successful in all patients. Inferior vena cavography demonstrated that all of the inferior vena cavae were patent without incidental pulmonary embolism after deploying the stent filter. A 3∼11 months follow-up study showed that all of the stent filters were removed after approximately 5 to 24 days of placement. All patients were still alive with resolution of the symptoms. Conclusions The use of a retrieval stent filter proved to be expedient, safe, and effective in the treatment of Budd Chiari syndrome complicated with inferior vena cava thrombosis.

The main idea of this paper is to study the influence of the discontinuity of mechanical property of FGMs on the stress intensity factors by means of FEM calculations. The FGMs interface is classified into four kinds according to the discontinuity of mechanical properties and their derivatives across it. Mechanical models were established for fracture analysis of the functionally gradient elastic weak/micro-discontinuous interfaces. Finite element method was used to obtain SIFs of the interfacial crack, based on the discussion of which three methods to diminish SIFs were suggested: (a) to increase the sizes of the FGMs plates; (b) to reduce the weak-discontinuity of FGMs interface; (c) to make FGMs interface micro-discontinuous. A simple method to make FGMs interface micro-discontinuous is to make mechanical property of the FGM at one side of the interface to be the lower-rank polynomial truncated from Taylor series of that of the FGM at the other side. The first-rank micro-discontinuity is always enough to reduce SIFs notably, so, it is not necessary to manufacture FGMs interface with higher-rank micro-discontinuity in engineering.

Purpose: To evaluate the preliminary clinical efficacy and retrievability of a covered, retrievable, metallic hinged stent in the treatment of bronchial stump fistula (BPF). Material and Methods: Between April 2003 and March 2005, eight patients with bronchial stump fistula after pneumonectomy or lobectomy were treated with two types of covered, retrievable, metallic hinged stents. Type A stent was placed in six patients and type B in two under fluoroscopic guidance. The stent was removed with a retrieval set when BPF was healed or complications occurred. Results: Stent placement in the bronchial tree was technically successful in all patients, without procedure-related complications. Immediate closure of the BPF was achieved in all patients after the procedure. Stents were removed from all patients but one. Removal of the stents was difficult in two patients due to tissue hyperplasia. Patients were followed for 4–16 months. Placement of the stents remained stable in all patients except one due to severe cough. Permanent closure of BPF was achieved in seven (87.5%) of eight patients. Conclusion: Use of a covered, retrievable, expandable, metallic hinged stent is a simple, safe, and effective procedure for the closure of bronchial stump fistula. Retrieval of the stent seems feasible.

PURPOSE The present study evaluated the clinical results of covered tracheobronchial metallic stent placement in the management of gastrotracheal fistulas (GTFs) and gastrobronchial fistulas (GBFs). MATERIALS AND METHODS Sixteen patients with GTFs or GBFs after esophagogastrectomy were treated with one of two types of covered tracheobronchial metallic stents: a hinged stent or a straight stent. These included 12 GTFs and four GBFs. Thirteen hinged stents and three straight stents were placed during the initial procedure. Data regarding the technical success of stent placement, initial clinical success and failure, fistula reopening, and complications were obtained. RESULTS Stent placement was technically successful in all patients. The stent completely sealed off the fistula in 12 of 16 patients (75% initial clinical success rate), whereas the remaining four patients (25%) had persistent aspiration symptoms as a result of incomplete GTF or GBF closure (ie, initial clinical failure). During follow-up, the fistula reopened in three of the 12 patients in whom initial clinical success was achieved (25%). Two reopened fistulas were sealed off with stent placement, and one was treated with a nasoenteric feeding tube and a nasogastric decompression tube. All patients died during the 1-year follow-up period; mean survival time was 17 ± 3.02 weeks (range, 1–42 weeks) after stent placement. Mean survival in patients in whom initial clinical success was achieved was significantly longer than in patients with initial clinical failure ( P = .003; log-rank test). CONCLUSION Use of covered metallic stents appears to be a safe and moderately effective procedure to occlude GTFs and GBFs.

Purpose To evaluate the clinical results of a new covered mushroom-shaped metallic stent for managing gastroesophageal anastomotic leak after esophagogastrostomy with a wide gastric tube and gastric pull-up. Description The stent is a self-expanding prosthesis especially designed for occlusion of the esophago-thoracic anastomotic leaks after esophagogastrostomy. From January 2002 to September 2005, 8 patients with gastroesophageal anastomotic leaks were treated with stents. Information about the technical success of stent placement, definitive closure of leak, stent removal, and complications were obtained. Evaluation Stent placement was technically successful in all patients, without immediate procedural complications. The stent completely sealed off the fistula in all patients, and 30-day mortality was nil. Follow-ups at 7 to approximately 30 months showed that all leaks were healed without stent-related complications, and the stents were removed after approximately 18 to 48 days. Two patients died, and the remaining 6 patients were alive with no evidence of disease at the time of this report. Conclusions The use of a new covered mushroom-shaped metallic stent proved expedient, safe, and effective in the treatment of gastroesophageal anastomotic leaks.