In Vitro Evaluation of Fusiform-Shaped Stents for Wide-Neck Intracranial Aneurysm Treatment / 신경중재치료의학

PURPOSE: Wide-neck aneurysms (WNAs) associated with a dilated parent artery (PA) are not uncommon morphological abnormalities and usually cause inappropriate wall apposition and incomplete neck coverage of a tubular stent in stent-assisted coiling of aneurysms. We aimed to introduce a fusiform-shaped stent (FSS) and test its effectiveness in treating intracranial WNAs associated with a dilated PA using a three-dimensional (3D) model. MATERIALS AND METHODS: Two FSS types were designed with the middle one-third segment dilated by 10% (FSS10) and 20% (FSS20) and were compared with the tubular-shaped stent (TSS). A patient-specific 3D WNA model was prototyped and produced, and in vitro stent placement was performed. Angiographic images of the three stent types were analyzed and compared using predetermined parameters. RESULTS: The stent lumens were significantly larger in FSS10 and FSS20 than in TSS in the middle segments (P=0.046), particularly FSS20 (P=0.018). The non-covered area at the ostium tended to be smaller in FSS10 and FSS20 than in TSS, but the difference was not significant (P>0.05). The stent length was significantly longer in FSS10 and FSS20 than in TSS. The stent cell size was significantly larger in FSS than in TSS. CONCLUSION: Better vessel wall apposition and aneurysmal neck coverage was observed for FSS than for TSS. No significant difference was observed between FSS10 and FSS20.

In Vitro Quantification of the Radiopacity of Onyx during Embolization / 신경중재치료의학

PURPOSE: Onyx has been successfully applied in the treatment of various neurovascular lesions. However, some experience is required to get accustomed to its unpredictable fluoroscopic visibility during injection. This in vitro study aimed to evaluate the characteristics of radiopacity change in a simulated embolization procedure. MATERIALS AND METHODS: Using a bench-top Onyx injection experiment simulating a typical brain arteriovenous malformation embolization, nine cycles of casting modes (continuous injection) and plugging modes (injection with intermittent pauses) were performed. Radiodensity of Onyx droplets collected from the microcatheter tip and the distal head portion of the microcatheter were measured as time lapsed. Distribution of droplet radiodensity (radiodensity) and distribution of radiographic grade (grade) were analyzed and compared by repeated measurements. RESULTS: Within-group analysis revealed no significant radiodensity change with time (P>0.05). The radiodensity was significantly higher in the casting mode than in the plugging mode (P<0.01). The lateral radiograph of the microcatheter showed higher radiopacity (P<0.01) and better evenness (P<0.01) in the casting mode than in the plugging mode. A significant difference in microcatheter attenuation (both radiographic grade mean and SD; P<0.01) was noted between the two modes. Radiodensity had a significant influence on the radiopacity and radiopacity evenness of the microcatheter. CONCLUSION: The radiopacity of the Onyx can vary significantly over time because of early precipitation of tantalum powder. Radiopacity decreased significantly during plugging modes, characterized by pauses between injections.

Enlarged Parent Artery Lumen at Aneurysmal-Neck Segment in Wide-Necked Distal Internal Carotid Artery Aneurysms / 신경중재치료의학

PURPOSE: Hypothesizing that the parent artery (PA) diameter of the aneurysm-neck segment is larger than those of normal segments, especially in wide-necked aneurysm cases, we conducted 3D angiographic analyses in wide-necked aneurysm cases focusing on the luminal morphologic change of the PA. MATERIALS AND METHODS: Under the approval of local IRB, we enrolled 26 patients with distal internal carotid artery (ICA) aneurysms, which were treated with stent assisted coiling. The PA diameters along the centerline were measured at 6 points with built-in software by two observers. Those 6 points were P1 and P2 proximally, P3 and P4 at the aneurysm ostium margins, and P5 and P6 distally. We performed an ANOVA test and a Bonferroni method for post hoc analyses. Linear regression analysis was performed to find any morphologic influencing factors. RESULTS: There were 20 distal ICA aneurysms out of 26 consecutive cases after exclusion. The differences in diameter at each point were statistically significant (p<0.0001). On post hoc analyses, the difference between P4 and P5 was significant both in maximum and mean PA diameters (p<0.0001 and p<0.001, respectively). Multivariate analyses failed to reveal any morphological influencing factor. CONCLUSION: PAs harboring a wide-necked aneurysm requiring stent assistance for coiling showed significant enlargement of the lumen, especially at the distal transition segment of the aneurysm ostium and the PA.

Conjunctival Epithelial Cells Auto-Cultivated In Vivo on Human Amniotic Membrane in Rabbits

PURPOSE: The purpose of this study was to investigate the phenotype of conjunctival epithelial cells auto-cultivated in vivo on human amniotic membrane (CIVAMs) in rabbits for ocular surface reconstruction. METHODS: A fornix based-conjunctival flap 8 mm in diameter was made in 12 eyes of rabbits. Amniotic membrane was implanted into the conjunctival defects. Rabbit conjunctival epithelial cells were cultivated in vivo on amniotic membrane for a week. A frozen section was made of the excised specimen. To investigate the phenotype of CIVAMs, Hematoxylin-eosin staining, immunohistochemical staining to anti-MUC5AC (monoclonal antibody to conjunctival goblet cell mucin), and transmission electron microscopy were performed. RESULTS In 11 of 12 eyes, conjunctival epithelial cells grew successfully on amniotic membrane. Light microscopy demonstrated two to three layers of cuboidal epithelial cells and two to three layers of stratified epithelial cells in CIVAMs. CIVAMs exhibited non-goblet epithelial differentiation as determined by immunohistochemistry to anti-MUC5AC. Transmission electron microscopy of CIVAMs showed fine structure similar to that of normal conjunctival epithelial cells. CONCLUSIONS: CIVAMs showed morphological findings similar to normal conjunctival epithelial cells and are expected to accomplish more rapid reconjunctivalization than simple amniotic membrane transplantation. We expect that CIVAMs will be adopted in treating conjunctival burn, symblepharon, conjunctiva-scleral ulcer, and filtering bleb leakage with conjunctival defects.

Conjunctival Epithelial Cells Auto-Cultivated In Vivo on Human Amniotic Membrane in Rabbits

PURPOSE: The purpose of this study was to investigate the phenotype of conjunctival epithelial cells auto-cultivated in vivo on human amniotic membrane (CIVAMs) in rabbits for ocular surface reconstruction. METHODS: A fornix based-conjunctival flap 8 mm in diameter was made in 12 eyes of rabbits. Amniotic membrane was implanted into the conjunctival defects. Rabbit conjunctival epithelial cells were cultivated in vivo on amniotic membrane for a week. A frozen section was made of the excised specimen. To investigate the phenotype of CIVAMs, Hematoxylin-eosin staining, immunohistochemical staining to anti-MUC5AC (monoclonal antibody to conjunctival goblet cell mucin), and transmission electron microscopy were performed. RESULTS In 11 of 12 eyes, conjunctival epithelial cells grew successfully on amniotic membrane. Light microscopy demonstrated two to three layers of cuboidal epithelial cells and two to three layers of stratified epithelial cells in CIVAMs. CIVAMs exhibited non-goblet epithelial differentiation as determined by immunohistochemistry to anti-MUC5AC. Transmission electron microscopy of CIVAMs showed fine structure similar to that of normal conjunctival epithelial cells. CONCLUSIONS: CIVAMs showed morphological findings similar to normal conjunctival epithelial cells and are expected to accomplish more rapid reconjunctivalization than simple amniotic membrane transplantation. We expect that CIVAMs will be adopted in treating conjunctival burn, symblepharon, conjunctiva-scleral ulcer, and filtering bleb leakage with conjunctival defects.

The Effects of Lateral Tarsal Strip Procedure on the Functional Nasolacrimal Duct Obstruction

PURPOSE: To evaluate the effects of the lateral tarsal strip procedure in the treatment of lacrimal pump dysfunction related to lower lid laxity. METHODS: This study investigated 46 eyes of 35 patients diagnosed with dysfunction of the lacrimal pump on which the lateral tarsal strip procedure was performed between June 2001 and February 2004. We retrospectively reviewed patients' medical records for information including age, gender, history, follow-up period, change of fluorescein dye disappearance test (DDT), tear meniscus height (TMH), symptoms, and complications. RESULTS: Improvement of tearing was noted in 26 patients (78.8%). Thirty-seven eyes (80.5%) were improved by more than 1 grade on DDT. Significant improvement above 2 grades was observed in 16 eyes (34.7%). With respect to age, 62.5% of 3rd-decade patients improved most effectively by more than 2 grades on DDT. Postoperative TMH compared with preoperative TMH measures were significantly lower according to statistics. The most common complication was discomfort or tenderness over the orbital rim (13.0%). CONCLUSIONS: Performance of the lateral tarsal strip procedure for tearing caused by dysfunction of the lacrimal pump and related to lower lid laxity improved patients' tearing, DDT and TMH status. We therefore expect the lateral tarsal strip procedure to be effective in the surgical treatment of lacrimal pump dysfunction secondary to lower eyelid laxity.

The Clinical Characteristics and Treatment Results of Ocular Adnexal Lymphoma

PURPOSE: To assess the clinical pattern, the histopathological findings, the response to treatments, the recurrence pattern and the prognosis of malignant lymphoma in the ocular adnexa. METHODS: This study was performed on 22 total eyes from 17 patients who were diagnosed with ocular adnexal malignant lymphoma. We retrospectively analyzed the medical records for patient information including the histological classification based on age, the gender of each patient, the symptoms and signs at the initial diagnosis, the presence of binocular invasion, the findings of the surgical biopsy, the clinical stage of each patient's tumor, and the treatment methods used and their effectiveness. The mean follow-up period was 24.8 months. RESULTS: The mean age of patients studied was 46.8 years old. Six females and 11 males were included in the study. Fifteen cases consisting of 20 total eyes represented extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT). Five of seven patients (71.4%) whose lymphoma occurred within the conjunctiva relapsed after irradiation or chemotherapy, and four of the relapsed patients were salvaged with further therapy. CONCLUSIONS: Extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT) constituted 88.2% of all lymphomas involving the ocular adnexa. Lymphoma in the ocular adnexa responded well to conventional treatment, but the recurrence rate of lymphoma in the conjunctiva was significantly high.

The Characteristics of Limbal Epithelial Cells Auto-Cultivated In Vivo on Amniotic Membrane in Rabbits

PURPOSE: To investigate the characteristics of the limbal epithelial cells auto-cultivated in vivo on amniotic membrane (LIVAMs) designed for the treatment of limbal stem cell deficiency. METHODS: We removed the epithelium of AM with a No.15 blade after it was blotted with 20% ethanol and made a 360 degrees stromal flap along the epithelial defect. We then mounted over-sized AM (1 mm larger in diameter than the defect) over the defect with the border of AM inserted under the flap, and performed interrupted suture with 10-0 nylon. A therapeutic contact lens was fitted over the AM and a temporary tarsorrhaphy was performed. To examine whether the limbal epithelial cells grew well onto AM, we observed the cornea after fluorescein dye staining using a slit lamp. To explore the characteristics of LIVAMs, we performed hematoxylin-eosin (H&E) staining, immunochemical staining with AK-2, AE-5, AM-3 monoclonal antibodies, and transmission electron microscopy. RESULTS: Three of four rabbits had successful epithelial growth on the amniotic membrane. The epithelial growth on the amniotic membrane was stained using immunohistochemical staining (AK-2, AE-5). Electron microscopy showed a structure similar to that of a normal corneal epithelium. CONCLUSIONS: The technique of auto-cultivation of limbal epithelial cells in vivo on amniotic membrane can be an efficient and convenient method and preserves the characteristics of limbal epithelial cells for the treatment of limbal stem cell deficiency.