ABSTRACT
With relatively low rejection rate and better visual prognosis, Descemet membrane endothelial keratoplasty (DMEK) has become the mainstream surgery for the treatment of endothelial dysfunction in some developed countries, but it has not been applied widely in China due to technical difficulties, the long learning curve, shallow anterior chamber of Chinese people, and the fact that domestic corneal endothelial lesions are often accompanied with other complex eye diseases.In this review, the indications, donor graft preparation including donor selection, graft preparation techniques and visualization of graft, key surgical techniques including the implantation, unwrapping and positioning of graft, postoperative complications including graft detachment, high intraocular pressure, rejection, endothelial cell loss, graft survival rate, and visual prognosis of DMEK were reviewed.
ABSTRACT
PURPOSE: To design a simple, cost-effective system for gaining rapid and accurate calyceal access during percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: The design consists of a low-cost, light-weight, portable mechanical gantry with a needle guiding device. Using C-arm fluoroscopy, two images of the contrast-filled renal collecting system are obtained: at 0-degrees (perpendicular to the kidney) and 20-degrees. These images are relayed to a laptop computer containing the software and graphic user interface for selecting the targeted calyx. The software provides numerical settings for the 3 axes of the gantry, which are used to position the needle guiding device. The needle is advanced through the guide to the depth calculated by the software, thus puncturing the targeted calyx. Testing of the system was performed on 2 target types: 1) radiolucent plastic tubes the approximate size of a renal calyx (5 or 10 mm in diameter, 30 mm in length); and 2) foam-occluded, contrast-filled porcine kidneys. RESULTS: Tests using target type 1 with 10 mm diameter (n = 14) and 5 mm diameter (n = 7) tubes resulted in a 100 percent targeting success rate, with a mean procedure duration of 10 minutes. Tests using target type 2 (n = 2) were both successful, with accurate puncturing of the selected renal calyx, and a mean procedure duration of 15 minutes. CONCLUSIONS: The mechanical gantry system described in this paper is low-cost, portable, light-weight, and simple to set up and operate. C-arm fluoroscopy is limited to two images, thus reducing radiation exposure significantly. Testing of the system showed an extremely high degree of accuracy in gaining precise access to a targeted renal calyx.
Subject(s)
Kidney Calices/surgery , Nephrostomy, Percutaneous/instrumentation , Surgery, Computer-Assisted/instrumentation , Cost-Benefit Analysis , Equipment Design , Fluoroscopy , Needles , Nephrostomy, Percutaneous/methods , Reproducibility of Results , Robotics/instrumentation , Surgery, Computer-Assisted/methods , Time FactorsABSTRACT
La membrana amniótica ha sido usada desde hace varios años como injerto o recubrimiento que permite solucionar los principales problemas de superficie ocular. La similitud histológica entre la membrana basal del amnios y la conjuntiva, permite que el trasplante sea exitoso en propiciar el crecimiento de nuevas células epiteliales progenitoras que sustituyan el epitelio dañado en superficies corneanas lesionadas. En la presente revisión se muestran las diferentes causas de lesión de la superficie ocular y las diversas alternativas para su tratamiento
Subject(s)
Amnion , Corneal Diseases , Limbus Corneae , TransplantsABSTRACT
A superfície ocular é revestida pelo epitélio corneano, límbico e conjuntival, cada um com um fenótipo celular distinto. A conjuntiva reveste as superfícies internas das pálpebras superior e inferior, e cobre a esclera anterior antes de terminar no epitélio do limbo, que é a transiçäo entre os epitélios corneano e conjuntival. O epitélio corneano, juntamente com filme lacrimal contribuem para a manutençäo da superfície opticamente regular da córnea, promovendo uma visäo nítida e adequada. Para assegurar uma superfície ocular íntegra é necessário que esta esteja constantemente coberta por um filme lacrimal estável. Recentemente, cinco importantes conceitos foram relatados para explicar como um sistema de defesa eficaz e organizado é estabelecido para se atingir este objetivo: 1) O bom estado da superfície ocular é assegurado por uma estreita relaçäo entre o epitélio da superfície ocular e o filme lacrimal; 2) A estabilidade do filme lacrimal é mantida por anexos externos; 3) O mecanismo de proteçäo em sua íntegra é controlado por uma integraçäo neuroanatômica eficaz; 4) As células germinativas (CG) epiteliais corneanas estäo localizadas no limbo; 5) A funçäo das células epiteliais da superfície ocular é mantida pela matriz e por fibroblastos do estroma.
Subject(s)
Humans , Biological Dressings , Corneal Transplantation/rehabilitationABSTRACT
Scarless wound healing with minimal inflammation obscured in the fetal skin rpay be due to the fact that amniotic fluid contains factors that may modulate the wound healing process. To examine this possibility, We examined the effect of topical application of human amniotic fluid on the healing of rabbit corneal wounds induced by excimer laser stromal ablation. The right eye received undiluted human amniotic fluid(AF) drops(13th week gestational age) and the left eye received the BSS as a control five times a day for one month. Epithelial healing completed within three days. The wound healing rate was not significant in the early phase but was significant in the late phase(p<0.05). Keratometric regression was significantly less in human amniotic fluid treated(AF group) eyes than BSS treated(control group) eyes. Corneal opacity was significantly less in AF group than control group at one and three months after laser ablation using Scheimpflug camera photography and MacDonald-Schadock class ification(p<0.05). Morphological examination revealed convoluted basement membrane, discontinued hemidesmosome and increased number of activated keratocytes in BSS-treated eyes. These results indicate that corneal scarring(haze) can be reduced by topical application of human amniotic fluid. We speculate that amniotic fluid may contain factors that can facilitate the restoration of fetal environment for wound healing by inhibiting fibroblast activation, thus preventing scar formation.
Subject(s)
Female , Humans , Rabbits , Amniotic Fluid , Basement Membrane , Cicatrix , Corneal Opacity , Fibroblasts , Hemidesmosomes , Inflammation , Laser Therapy , Lasers, Excimer , Photography , Skin , Wound Healing , Wounds and InjuriesABSTRACT
Human amniotic membrane isolated from the placenta contained basement membrane components such as type IV collagen, laminin, and 6 and 4 integrins, all of which remained detectable while preserved in glycerin for one week. One month after the n-heptanol removal of the total corneal epithelium and the limbal lamellar keratectomy, all rabbit eyes carried features of limbal deficiency, including conjunctival epithelial ingrowth, vascularization and chronic inflammation. Ten control eyes then received a total keratectomy, and 13 experimental eyes received an additional amniotic membrane transplantation. Three-month follow-ups revealed that all control corneas were revascularized to the center with granuloma and retained a conjunctival phenotype. In contrast, in the experimental groups, 5 corneas became clear with either minimal or no vascularization; the rest had either mild peripheral (5) or total (3) vascularization and more cloudy stroma. Using monoclonal antibodies for epithelial markers and matrix components, we concluded that the success correlated with the return of a cornea-like epithelial phenotype and the preservation of the amniotic membrane, whereas the failure maintained a conjunctival epithelial phenotype and the amniotic membrane was either partially degraded or covered by host fibrovascular stroma. Measures taken to facilitate the former might prove this procedure clinically useful for ocular surface reconstruction.