Homemade lyophilized cross linking amniotic sustained-release drug membrane with anti-scarring role after filtering surgery in rabbit eyes

AIM: To investigate the antifibrotic effect of the freeze-dried bilayered fibrin-binding amniotic membrane as a drug delivery system on glaucoma surgery in rabbit model. The aim of this study was to prepare a novel local delivery system for the sustained and controllable release of 5-Fu. METHODS: Twenty-four Japanese white rabbits were randomized into three groups: the experimental group (ocular trabeculectomy in combination with 5-Fu loaded freeze-dried bilayered fibrin-binding amniotic membrane transplantation), the control group (ocular trabeculectomy in combination with 5-Fu) and the blank group (single trabeculectomy). HE staining, massion staining and immunohistochemistry for alpha -SMA were performed on days 7, 14, 21 and 30 following surgery. The concentration of 5-Fu in rabbit aqueous humor was examined by high performance liquid chromatography (HPLC) 3 days after the surgery. RESULTS: Statistical differences were noted in intraocular pressure among groups on day 7, 14, 21 and 30 following surgery. Histology further demonstrated that trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane yielded well wound healing and no scar formation and was beneficial for long term effect. CONCLUSION: HPLC showed a good slow-release effect with freeze-dried bilayered fibrin-binding amniotic membrane.

Anti-scarring effect of sodium hyaluronate at filtration pathway after filtering surgery in rabbits

AIM: To investigate the anti-scarring effect of sodium hyaluronate(HA) at filtration pathway after filtering surgery in a rabbit model.METHODS: Fifteen healthy adult New Zealand white rabbits were selected for trabeculectomy in both eyes. The right eyes were used as HA group with 0.1 m L HA injected into the anterior chamber at the end of the operation;the left eyes were used with 0.1 m L sodium lactate Ringer’s solution(RS) injected into the anterior chamber as RS group. Intraocular pressure(IOP), filtering blebs morphology, inflammatory reaction and complications were observed at the 7, 60, and 90 d after surgery.RESULTS: One day after surgery, the IOP of HA and RS groups were 12.75±1.92 and 10.50±1.59 mm Hg(P=0.005). At the 7;day postoperative, the filtering blebs of each group were functional type and TGF-β expression was significantly difference in both groups(0.10±0.01 vs 0.14±0.02, P=0.024). After 60 d of the operation, all filtering blebs were scarring and alpha-smooth muscle actin(α-SMA) expression was significantly difference in both groups(0.40±0.04 vs 0.35±0.02, P=0.032). α-SMA positive cells were mainly distributed in the junction of conjunctiva and sclera and around the blood vessels. The collagen volume fraction(CVF) of HA and RS group was(75.49±7.01)% and(79.93±5.35)%(P=0.044). On the 90;day after the operation, CVF was(82.57±5.19)% and(88.08±1.75)% in HA and RS groups(P=0.036). There was no α-SMA positive cell in HA group, while a few positive cells were observed in RS group(P=0.000).CONCLUSION: HA has effect of anti-scar and antiinflammation on filtration pathway after filtering surgery within 3 mo by inhibiting fibroblast proliferation and collagen deposition.

A novel suturing technique for filtering glaucoma surgery:the accordion suture

AIM：To present a novel scleral flap suturing technique for filtering glaucoma surgery in order to control high postoperative intraocular pressure（IOP）.METHODS：Description of ‘the accordion suture＇ technique for mitomycin C augmented trabeculectomy.In cases of postoperative high IOP,pulling the loop of the suture helps to lift up the scleral flap by an even pressure on both edges.By means of this technique,the scleral flap opens up in an ‘‘accordion＇＇ manner,thus preventing flap obstruction and providing adequate aqueous flow.RESULTS：Our study group consisted of 8 eyes of 8 patients with neovascular glaucoma.Mean age of the subjects was 67.42±8.21 y and female/male ratio was 4/4.Mean preoperative IOP was 37±7.48 mm Hg.Mitomycin C augmented trabeculectomy was carried out on the subjects without any complications.The scleral flap closure is performed with three separate sutures;initially,our accordion suture through the center of the flap,and two releasable sutures on both corners.All the patients received removal of two side releasable sutures concomitant with pulling the accordion suture,without any complications.The average traction time was 3.5±0 wk postoperatively.The mean postoperative IOP was 11.37±2.72 mm Hg.No suture related complications were observed.CONCLUSION：This technique can be the suture of choice for filtering glaucoma surgery in experienced hands by its easy learning curve for precisely indicated patients.

A new bleb-independent surgery namely penetrating canaloplasty for corticosteroid-induced glaucoma: a prospective case series

AIM: To report the outcomes of penetrating canaloplasty for corticosteroid-induced glaucoma in a case series.METHODS: Penetrating canaloplasty is a blebindependent filtering surger y unifying canaloplasty and trabeculectomy. In this study, the surger y was performed to restore the natural outflow through surgically expanded Schlemm’s canal and generated trabeculum ostium. A total of 10 eyes of 8 patients were treated with penetrating canaloplasty for corticosteroid-induced glaucoma. Intraocular pressure(IOP) and the number of glaucoma medications at postoperative 3, 6, 12, 18, 24,36, and 48mo were documented as primary endpoint.Complications after the surgery were recorded as secondary endpoint.RESULTS: Penetrating canaloplasty was accomplished successfully for all 10 eyes, with a mean follow-up of 20.4±13.0mo(range 6-48mo). The mean preoperative IOP and number of anti-glaucoma medications were 45.1±6.5 mm Hg and 3.3±0.5 respectively. The mean post-operative IOP at 3, 6, 12, 18, 24, 36, and 48mo were 15.8±6.0, 14.7±3.3,15.3±2.0, 15.6±2.6, 17.5±1.8, 16.5±4.9, and 14.0 mm Hg.The number of anti-glaucoma medications at these time points were all 0. This surgery failed to control the IOP in 1 eye at 1mo after surgery. Hyphaema occurred in 3 eyes on the first day after surgery. Postoperative transient IOP increasing was encountered with in two eyes from 1wk to 1mo after surgery. Choroidal detachment developed in one eye but responded well to conservative treatment.CONCLUSION: Penetrating canaloplasty is effective for corticosteroid-induced glaucoma without serious complications, making it a viable or preferred alternative option.