The use of collagen matrix (Ologen) as a patch graft in glaucoma tube shunt surgery, a retrospective chart review.
ABSTRACT: Purpose: To determine the safety and efficacy of collagen matrix as a patch graft in glaucoma drainage surgery. Collagen matrix grafts may be advantageous because they do not need to be harvested from human donors. Methods: An institutional, retrospective review of 43 patients with at least 12 months follow-up status post-glaucoma drainage implant surgery were evaluated for signs of tube erosion after initial placement of collagen matrix patch graft. Results: Forty-one of 43 eyes (95.3%) required no intervention for patch graft melting with tube erosion. Average time of follow-up was 32 months (range: 12-45). Two cases had tube erosion at 4 months and 26 months post-op requiring tube revision, which was successfully revised with conjunctiva (4 month erosion) and donor sclera (26 month erosion). Conclusion: Our results suggest that collagen matrix patch grafts may be used successfully as a patch graft in glaucoma tube shunt surgery, and may be advantageous because they do not have to be harvested from human donors. It is possible that exposure rates may be higher after longer follow-up and with larger numbers of patients. Further research is needed to compare Ologen to traditional graft materials to conclusively determine the safety and efficacy of collagen matrix as a novel patch graft material.
Project description:To report the first successfully treated case of recurrent tube exposure in a patient with the Boston Keratoprosthesis type 1 with a collagen matrix patch graft (Ologen).A 50 year-old female with a Boston Keratoprosthesis type 1 and a history of Axenfeld-Reiger syndrome presents to our department with recurrent glaucoma drainage device exposure in her left eye. After failed spontaneous closure with topical antibiotics and lubricants, she undergoes tube exposure repair using an Ologen patch graft. Surgery was successful and the patient did not have any recurrence up to last follow-up two years post-operatively.Collagen matrix patch graft seems to be advantageous in treating glaucoma tube exposure in the Boston KPro eye, which is often a more challenging entity to treat.Collagen matrix patch graft could be considered as a primary patch graft in treating tube exposure in eyes with the Boston KPro.
Project description:PURPOSE:To compare the long-term safety and efficacy of amniotic membrane-umbilical cord (AM-UC) and pericardium patch grafts in reducing glaucoma shunt tube exposure. DESIGN:Multicenter, prospective, randomized clinical trial. PARTICIPANTS:Adults with uncontrolled glaucoma undergoing glaucoma drainage device (GDD) implantation. METHODS:Patients were randomized to receive GDD with either AM-UC or pericardium patch grafts to cover GDD tubes. Patients were followed up clinically with anterior segment (AS) OCT to assess patch graft stability and host-tissue integration prospectively. MAIN OUTCOME MEASURES:Tube exposure, graft thinning, and graft-related complications. RESULTS:A total of 81 eyes of 81 patients (50 women, 31 men) with a mean age of 67±13 years underwent GGD implantation using Baerveldt (n = 72) or Ahmed valve (n = 9). Tubes were inserted in the anterior chamber (n = 71), sulcus (n = 6), or pars plana (n = 4). Tube ligation was performed with Baerveldt GDD along with fenestration (n = 51) or orphan trabeculectomy (n = 21). Tubes were covered with AM-UC (n = 41) or pericardium (n = 40). The mean follow-up time was 29±8 months (range, 13-40 months). Tube exposure occurred in 1 eye (2%) in the AM-UC group at 3 months and in 2 eyes (5%) in the pericardium group at 2 and 6 months (P = 0.54). Sequential AS OCT showed better host-tissue integration and significantly less graft thinning in the AM-UC group. Early graft thinning (?3 months) occurred in 5 eyes (12%) in the AM-UC group and in 17 eyes (43%) in the pericardium group (P = 0.002). Late thinning occurred in 2 eyes (5%) and 11 eyes (28%) in the AM-UC and pericardium groups, respectively (P = 0.007). Graft translucency and cosmetic appearance of the AM-UC graft were superior to those of the pericardium graft. No evidence of graft rejection or infection was associated with the patch grafts in either group. CONCLUSIONS:Amniotic membrane-umbilical cord grafts are well tolerated and offer an alternative to pericardium for safe and stable tube shunt coverage. Its high-tensile strength, low immunogenicity, and excellent host-tissue integration significantly reduced graft thinning.
Project description:Exposure of the tube of an aqueous drainage device (ADD) through the conjunctiva is a serious complication of ADD surgery. Although placement of gamma-irradiated sterile cornea (GISC) as a patch graft over the tube is commonly performed, exposures still occur.To measure GISC patch graft thickness as a function of time after surgery, estimate the rate of graft thinning, and determine risk factors for graft thinning.Cross-sectional study of graft thickness using anterior segment optic coherence tomography (AS-OCT) was conducted at the Wilmer Eye Institute at Johns Hopkins Hospital. A total of 107 patients (120 eyes, 120 ADDs) 18 years or older who underwent ADD surgery at Johns Hopkins with GISC patch graft between July 1, 2010, and October 31, 2016, were enrolled.Implantation of ADD with placement of GISC patch graft over the tube.Graft thickness vs time after ADD surgery and risk factors for undetectable graft.Of the 107 patients included in the analysis, the mean (SD) age of the cohort was 64 (16.2) years, 49 (45.8%) were male, and 43 (40.2%) were African American. The mean time of measurement after surgery was 1.7 years (range, 1 day to 6 years). Thinner grafts were observed as the time after surgery lengthened (??regression coefficient, -60 µm per year since surgery; 95% CI, -80 µm to -40 µm). The odds ratio of undetectable grafts per year after ADD surgery was 2.1 (95% CI, 1.5-3.0; P?<?.001). Age, sex, race, type of ADD, quadrant of ADD placement, diagnosis of uveitis or dry eye, and prior conjunctival surgery were not correlated with the presence or absence of the graft.Gamma-irradiated sterile corneal patch grafts do not always retain their integrity after ADD surgery. Data from this cross-sectional study showed that on average, the longer the time after surgery, the thinner the graft. These findings suggest that placement of a GISC patch graft is no guarantee against tube exposure, and that better strategies are needed for preventing this complication.
Project description:A fundamental mechanism of in situ tissue regeneration from biodegradable synthetic acellular vascular grafts is the effective interplay between graft degradation, erosion and the production of extracellular matrix. In order to understand this crucial process of graft erosion and degradation, we conducted an in vitro investigation of grafts (n = 4 at days 1, 4, 7, 10 each) exposed to enzymatic degradation. Herein, we provide constitutive relationships for mass loss and mechanical properties based on much-needed experimental data. Furthermore, we formulate a mathematical model to provide a physics-based framework for understanding graft erosion. A novel finding is that despite their porous nature, grafts lost mass exponentially via surface erosion demonstrating a 20% reduction in outer diameter and no significant change in apparent density. A diffusion based, concentration gradient-driven mechanistic model of mass loss through surface erosion was introduced which can be extended to an in vivo setting through the use of two degradation parameters. Furthermore, notably, mechanical properties of degrading grafts did not scale with mass loss. Thus, we introduced a damage function scaling a neo-Hookean model to describe mechanical properties of the degrading graft; a refinement to existing mass-dependent growth and remodelling (G&R) models. This framework can be used to improve accuracy of well-established G&R theories in biomechanics; tools that predict evolving structure-function relationships of neotissues and guide graft design.
Project description:Purpose:To introduce cases of the use, as patch grafts, of stromal lenticules obtained by small incision lenticule extraction (SMILE) surgery. Observations:Case 1 was a 79-year-old man who presented with Ahmed-valve-tube exposure in his left eye. His uncorrected visual acuity (UCVA) was 20/40, best-corrected visual acuity (BCVA) 20/32, and intraocular pressure (IOP) 11?mmHg. He was treated with stromal lenticule patch that had been extracted by SMILE surgery. The patch was positioned underneath of the conjunctiva and sutured to it. At postoperative 8 months, the graft site was well maintained without Ahmed valve-tube exposure, the UCVA was 20/32, BCVA 20/20, and IOP 12?mmHg.Case 2 was a 60-year-old man who presented with Ahmed-valve-tube exposure in his right eye. His UCVA was finger-count (FC) 30 cm, his BCVA 20/125, and his IOP 14?mmHg. He was treated with stromal lenticule patch by the same method as employed in case 1. At postoperative 10 days, tube re-exposure and displacement of the Ahmed valve external plate toward the limbus area occurred due to loosening of the anchoring suture. So, we removed the Ahmed valve device, which had been implanted in the supero-temporal area, and performed new Ahmed valve implantation, with a stromal lenticule flap instead of a partial scleral flap, in the supero-nasal area. As of 6 months post-reoperation, the patient was stable, with UCVA 20/200, BCVA 20/40 and IOP 13?mmHg.Case 3 was a 74-year-old man who presented with bullous keratopathy in his right eye, which was blind. Due to severe adhesions, his conjunctiva could not cover the entire cornea. Therefore, we performed a stromal lenticule patch graft with conjunctival advance flap. At postoperative 3 months, the patient's right eye was stable, without displacement or melting of the lenticule graft. Conclusions & importance:It is suggested that the stromal lenticule, with its biocompatibility, sufficient strength, ease of handling and low cost, is a useful patch graft for various therapeutic purposes in the ophthalmic field.
Project description:Autologous veins are the most widely used grafts for bypassing small arteries in coronary and peripheral arterial occlusive diseases. However, they have limited availability and cause donor-site morbidity. Here, we report a direct comparison of acellular biodegradable synthetic grafts and autologous veins as interposition grafts of rat carotid arteries, which is a good model for clinically relevant small arteries. Notably, extensive but transient infiltration of circulating monocytes at day 14 in synthetic grafts leads to a quickly-resolved inflammation and arterial-like tissue remodeling. The vein graft exhibits a similar inflammation phase except the prolonged presence of inflammatory monocytes. The walls of the remodeled synthetic graft contain many circumferentially aligned contractile non-proliferative smooth muscle cells (SMCs), collagen and elastin. In contrast, the walls of the vein grafts contain disorganized proliferating SMCs and thicken over time, suggesting the onset of stenosis. At 3 months, both grafts have a similar patency, extracellular matrix composition, and mechanical properties. Furthermore, synthetic grafts exhibit recruitment and re-orientation of newly synthesized collagen fibers upon mechanical loading. To our knowledge, this is the first demonstration of a biodegradable synthetic vascular graft with a performance similar to an autologous vein in small artery grafting.
Project description:The surgical repair of heart and vascular disease often requires implanting synthetic grafts. While synthetic grafts have been successfully used for medium-to-large sized arteries, applications for small diameter arteries (<6 mm) is limited due to high rates of occlusion by thrombosis. Our objective was to develop a tissue engineered vascular graft (TEVG) for small diameter arteries. TEVGs composed of polylactic acid nanofibers with inner luminal diameter between 0.5 and 0.6 mm were surgically implanted as infra-renal aortic interposition conduits in 25 female C17SCID/bg mice. Twelve mice were given sham operations. Survival of mice with TEVG grafts was 91.6% at 12 months post-implantation (sham group: 83.3%). No instances of graft stenosis or aneurysmal dilatation were observed over 12 months post-implantation, assessed by Doppler ultrasound and microCT. Histologic analysis of explanted TEVG grafts showed presence of CD31-positive endothelial monolayer and F4/80-positive macrophages after 4, 8, and 12 months in vivo. Cells positive for ?-smooth muscle actin were observed within TEVG, demonstrating presence of smooth muscle cells (SMCs). Neo-extracellular matrix consisting mostly of collagen types I and III were observed at 12 months post-implantation. PCR analysis supports histological observations. TEVG group showed significant increases in expressions of SMC marker, collagen-I and III, matrix metalloproteinases-2 and 9, and itgam (a macrophage marker), when compared to sham group. Overall, patency rates were excellent at 12 months after implantation, as structural integrity of these TEVG. Tissue analysis also demonstrated vessel remodeling by autologous cell.
Project description:A persistent clinical demand exists for a suitable arterial prosthesis. In this study, a vascular conduit mimicking the native 3-layered artery, and constructed from the extracellular matrix proteins type I collagen and elastin, was evaluated for its performance as a blood vessel equivalent. A tubular 3-layered graft (elastin-collagen-collagen) was prepared using highly purified type I collagen fibrils and elastin fibers, resembling the 3-layered native blood vessel architecture. The vascular graft was crosslinked and heparinised (37 ± 4 μg heparin/mg graft), and evaluated as a vascular graft using a porcine bilateral iliac artery model. An intra-animal comparison with clinically-used heparinised ePTFE (Propaten®) was made. Analyses included biochemical characterization, duplex scanning, (immuno)histochemistry and scanning electron microscopy. The tubular graft was easy to handle with adequate suturability. Implantation resulted in pulsating grafts without leakage. One week after implantation, both ePTFE and the natural acellular graft had 100% patencies on duplex scanning. Grafts were partially endothelialised (Von Willebrand-positive endothelium with a laminin-positive basal membrane layer). After one month, layered thrombi were found in the natural (4/4) and ePTFE graft (1/4), resulting in occlusion which in case of the natural graft is likely due to the porosity of the inner elastin layer. In vivo application of a molecularly-defined tubular graft, based on nature's matrix proteins, for vascular surgery is feasible.
Project description:PurposeTo evaluate the clinical outcome of Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with iridocorneal endothelial (ICE) syndrome.Patients and methodsA retrospective case series study was conducted. Eighteen consecutive Chinese patients with 20 DSAEK grafts were enrolled. Participants were evaluated by anterior segment optical coherence tomography and confocal microscopy. Postoperative complications, graft survival, endothelial cell counts, corneal thickness, and anterior chamber depth were analysed. A Log-rank test in a Kaplan-Meier analysis and a Cox proportional hazard regression were used to analyse potential risk factors of graft failure.ResultsThe mean follow-up duration was 19.0±8.6 months. The donors' endothelial cell density (ECD) (cells/mm2) values at 1, 3, 6, 12, 18, and 24 months were 3342.2±287.0, 1897.6±745.4, 1793.6±755.7, 1618.1±604.3, 1421.9±650.8, 1265.1±844.1, and 1148.2±1217.8, respectively. Eleven of the 20 grafts exhibited secondary graft failure, with a mean estimated graft survival of 23.4 months. Immediate postoperative complications (air bubble ventilation for elevated intraocular pressure or rebubbling for graft detachment) were more common in eyes exhibiting graft failure (P=0.040). Postkeratoplasty glaucoma surgery emerged as a risk factor of graft failure, with a hazard ratio of 5.174. Eyes with a poor prognosis showed statistically greater central corneal thickness at 1 month, greater graft thickness at 3 months, and a shallower anterior chamber at 6 and 12 months.ConclusionsThe long-term outcome of DSAEK in eyes with ICE syndrome is relatively poor. Immediate postoperative complications, postkeratoplasty glaucoma surgery, thicker corneal parameters, and a shallow anterior chamber were all associated with graft failure.
Project description:The laser speckle contrast imaging (LSCI) is proved to be a reliable tool in flap monitoring in general surgery; however, it has not been evaluated in oral surgery yet. We applied the LSCI to compare the effect of a xenogeneic collagen matrix (Geistlich Mucograft®) to connective tissue grafts (CTG) on the microcirculation of the modified coronally advanced tunnel technique (MCAT) for gingival recession coverage. Gingival microcirculation and wound fluid were measured before and after surgery for six months at twenty-seven treated teeth. In males, the flap microcirculation was restored within 3 days for both grafts followed by a hyperemic response. During the first 8 days the blood flow was higher at xenogeneic graft comparing to the CTG. In females, the ischemic period lasted for 7-12 days depending on the graft and no hyperemic response was observed. Females had more intense and prolonged wound fluid production. The LSCI method is suitable to capture the microcirculatory effect of the surgical intervention in human oral mucosa. The application of xenogeneic collagen matrices as a CTG substitute does not seem to restrain the recovery of graft bed circulation. Gender may have an effect on postoperative circulation and inflammation.