PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Filtering Surgery”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1996

Mechanisms of failure in glaucoma filtering surgery: a consequence of antiglaucomatous drugs?

An increasing number of studies, both experimental and epidemiologic, have provided evidence that filtering glaucoma surgery may be less effective than initially described. Of a number of risk factors for failure, duration and number of antiglaucoma drugs prior to surgery seem to play a critical role and highly accumulated antiglaucoma topical treatments significantly reduce success rates. Histopathological studies have confirmed that topically applied drugs may exert toxic effects to the corneoconjunctival surface, and induce chronic infraclinical inflammation, as shown by the presence of immune and inflammatory infiltrates in multitreated eyes. The origin of topical inflammation has not yet been clearly determined, but a common component of ophthalmic drugs, the benzalkonium chloride used as preservative in almost all antiglaucoma preparations, has shown strong evidence of toxicity. A number of questions remain to be investigated, but suppression of preservatives from chronically applied drugs should be a critical issue in the near future.

Animals↗
PubMed2004

[The experimental histopathologic changes of applying perfluoropropane to filtering surgery in rabbits].

OBJECTIVE: To study the histopathologic changes of filtering blebs by subconjunctival application of perfluoropropane (C(3)F(8)) after trabeculectomy in rabbit eyes. METHODS: Twenty rabbits were randomly divided into two groups, each group consisting of 10 rabbits. Trabeculectomy with topical application of C(3)F(8) was performed on one eye and trabeculectomy alone on the other eye in first group. Whereas, trabeculectomy with topical application of mitomycine (MMC) was performed on one eye and trabeculectomy with topical application of C(3)F(8) on the other eye in second group. Histopathologic changes in filter bleb were investigated by immunostaining at 3 days, and at week 1, 2, 3, and 4 after surgery. RESULTS: Fibroblasts: The numbers of fibroblasts in eyes after trabeculectomy with C(3)F(8) gas as well as trabeculectomy with MMC were significantly reduced (P < 0.05) compared to eyes with trabeculectomy alone. There was no significant statistical difference in the numbers of fibroblasts between trabeculectomy with C(3)F(8) gas group and trabeculectomy with MMC group. Newly formed collagen fiber: Immunostaining of collagen fibers showed that the numbers of newly formed collagen fibers in trabeculectomy with C(3)F(8) gas group and trabeculectomy with MMC group were significantly decreased compared to trabeculectomy alone group. However, there was no significant statistical difference between numbers of fibers in trabeculectomy with C(3)F(8) gas group and trabeculectomy with MMC group. Neovascularization and inflammation of filtering blebs: The differences were not statistically significant among trabeculectomy with C(3)F(8) gas, trabeculectomy with MMC group and trabeculectomy alone group. CONCLUSION: Trabeculectomy with subconjunctival retention of C(3)F(8) gas can enhance the success rates of surgery by suppressing the growth of fibroblasts and synthesis of newly formed collagen fibers, and by inhibiting scar formation.

Animals↗
PubMed1998

Basic science and clinical aspects of wound healing in glaucoma filtering surgery.

Success of glaucoma filtration surgery is influenced by the wound healing response. Attention has been focused on pharmacological agents to control a process that leads to excessive scarring and eventual failure of glaucoma filtration surgery. Several agents, including 5-fluorouracil and mitomycin C, as well as other antiproliferative drugs will be discussed. Newer antifibrotic agents and novel drug delivery systems are under development in tissue culture and animal models in an effort to improve efficacy and safety. This article summarizes current treatment modalities and future prospects to prevent excessive wound healing and improve the success of glaucoma filtration surgery.

Culture Techniques↗
PubMed2002

[Non penetrating filtering surgery, evolution and results].

Trabeculectomy is currently the standard filtration procedure for glaucoma surgical treatment. Despite several advantages over full-thickness procedures, trabeculectomy can be responsible for early postoperative complications related to sudden ocular decompression that can lead to hypotony with its sight-threatening complications. Nonpenetrating glaucoma surgeries, namely viscocanalostomy and deep sclerectomy with external trabeculectomy, have been developed in recent years in order to improve the safety of conventional filtering procedures. The goal of these procedures is to reduce intraocular pressure (IOP) by enhancing the natural aqueous outflow channels, while reducing outflow resistance, attributed for 75% to the trabecular meshwork and for 25% to the outer wall of Schlemm's canal (SC) or tissue surrounding it. In these procedures, the anterior chamber is not opened so that complications related to full thickness procedures are mainly avoided. In the last few years, viscocanalostomy and deep sclerectomy with external trabeculectomy have become the most popular nonpenetrating filtering procedures. Both involve the removal of a deep scleral flap, the external wall of SC, and corneal stroma behind the anterior trabecula and Descemet membrane, thus creating a scleral lake. The aqueous humor leaves the anterior chamber through the intact trabeculodescemetic membrane and reaches the scleral lake, from where it will egress into different pathways. In viscocanalostomy, a high-molecular viscoelastic substance is injected into the ostia of the SC in order to enlarge the SC and its collector channels. In deep sclerectomy with external trabeculectomy, the main goal is to remove the inner wall of the SC and the adjacent trabecular layers involved in aqueous outflow resistance, while leaving the innermost trabecular layers intact so that the anterior chamber does not open during operation. Different surgical adjuvants designed to maintain the scleral lake open are commercially available. Retrospective and prospective published studies have reported similar midterm results with trabeculectomy and nonpenetrating filtering procedures in terms of IOP control, with fewer postoperative complications and better visual acuity recovery with the nonpenetrating procedures. This article reviews the current nonpenetrating surgical procedure techniques, their mechanism of action, and their outcome.

Filtering Surgery↗
PubMed1987

Suprachoroidal hemorrhage after glaucoma filtering surgery.

We reviewed a series of 305 consecutive glaucoma filtering procedures performed by one surgeon. Five eyes (1.6%) had a postoperative suprachoroidal hemorrhage. All five eyes were aphakic, and four had undergone a partial or complete vitrectomy before the glaucoma surgery. The incidence of this complication was 13% (five of 37) among the aphakic eyes and 33% (four of 12) in the aphakic, vitrectomized eyes in this series. Despite drainage of the hemorrhage and reformation of the anterior chamber, three patients had a poor visual outcome.

Adult↗
PubMed2002

Nonpenetrating filtering surgery.

Trabeculectomy is currently the standard filtration procedure for surgical treatment of glaucoma. This technique has advantages over full thickness procedures but can cause early postoperative complications such as hyphema, shallow or flat anterior chamber, hypotony with the risk of choroidal detachment, and maculopathy. Nonpenetrating procedures are alternatives to trabeculectomy with the advantage of minimizing the risk of postoperative complications related to hypotony. The two major variations of nonpenetrating glaucoma surgery are nonpenetrating deep sclerectomy and viscocanalostomy. Techniques and results are discussed in this paper.

Filtering Surgery↗
PubMed1984

5-fluorouracil and glaucoma filtering surgery: I. An animal model.

Failure of a glaucoma filtering procedure commonly results from scarring at the surgical site. Fibroblasts play an important role in the scarring process. 5-fluorouracil is an antimetabolite capable of inhibiting fibroblast proliferation. We tested the ability of 5-fluorouracil to inhibit cicatrization at the filtering site in an experimental model. Posterior lip sclerectomies were performed in each eye of ten normal owl monkeys. Postoperatively, one eye of each animal received subconjunctival injections of fluorouracil and the fellow eye received saline injections in a randomized, masked fashion. Two animals died of undetermined causes. None of the control eyes developed blebs, but six of the eight treated eyes in surviving animals developed blebs. The difference between intraocular pressures in fluorouracil-treated and control eyes was statistically significant (P less than 0.05). Signs of ocular toxicity included persistent corneal epithelial defects and delayed healing of the conjunctival incision. These results are considerably more favorable than those previously reported with experimental filtering procedures in non-human primates. Pharmacologic modulation of wound healing may decrease the risk of failure of filtering operations.

Animals↗
PubMed2004

Microarray analysis of the failure of filtering blebs in a rat model of glaucoma filtering surgery.

PURPOSE: To generate data concerning changes in levels of protein expression associated with wound healing and bleb failure in a rat model of glaucoma filtration surgery (GFS), and to identify factors that may play a role in this process. METHODS: Of 36 Sprague-Dawley rats, GFS was performed on 27 by introducing a silicone cannula through a scleral tunnel under a conjunctival flap, resulting in aqueous-filtering blebs that failed over 8 to 13 days. The additional nine rats were used as the nonsurgical control. Nine blebs were harvested at each of days 0, 2, 5, and 12 and pooled, yielding three replicates of three blebs per time point. RNA was extracted, labeled, and hybridized to 230A rat GeneChip arrays (Affymetrix, Santa Clara, CA). RESULTS: Of the 15,924 probe sets/genes present on the array, 923 genes were indicated to have a significant treatment effect at P < 0.005. Eight gene expression clusters were identified that could be broadly classified into three basic patterns. These were an increase on day 2, a decrease on day 2, or an increase on either day 5 or 12. The greatest change occurred between days 0 and 2. The most heavily populated functional categories included growth factors, structural proteins, and matrix metalloproteinases. CONCLUSIONS: This study represents the first large-scale gene expression analysis after GFS. Expression patterns for known mediators of the bleb scarring process, including transforming growth factor-beta, connective tissue growth factor, and matrix metalloproteinases, were confirmed, and a number of mediators not previously associated with this process were identified.

Animals↗
PubMed1996

Bleb rupture following filtering surgery with mitomycin-C: clinicopathologic correlations.

A 91-year-old woman with a complete rupture of her mitomycin-C filtration bleb associated with eye rubbing while crying was examined. An 18mm soft contact lens was placed preoperatively to re-form the anterior chamber and the patient underwent a conjunctival advancement. Histopathology of the free conjunctival specimen revealed a stratified squamous epithelium with marked attentuation of the subepithelial tissue in the area treated with mitomycin-C. Bleb rupture may be associated with minimal physical trauma following guarded filtration surgery. Successful visual rehabilitation is possible with conjunctival advancement, yet long-term survival of the bleb is poor.

Aged↗
PubMedDate not supplied

Effect of mitomycin C dissolved in reversible thermo-setting gel on the outcome of filtering surgery in the rabbit.

PURPOSE: Based on our previous report that showed enhanced transfer of mitomycin C to the sclera and the conjunctiva by dissolving the agent into a reversible thermo-setting gel, we conducted a study to investigate the efficacy of mitomycin C gel in the rabbit. METHODS: We subconjunctivally injected 0.1 mL of the mitomycin C gel solution containing several different amounts of the agent. Trephination was performed in the injected region 24 hours later. Intraocular pressure measurement, photography, and ultrasound biomicroscopic examination of the filtering bleb were conducted 1, 2, and 4 weeks postoperatively. RESULTS: The gel containing 3.0 microg or more mitomycin C significantly enhanced bleb formation and reduction in the intraocular pressure. CONCLUSIONS: The reversible thermo-setting gel seems to help the filtering bleb to survive in the rabbit and deserves further investigation as a new method of mitomycin C application.

Animals↗
PubMed1998

Synthetic meshwork implant for glaucoma filtering surgery: effect of adjunct heparin and sodium hyaluronate in rabbits.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of a novel filtering implant, a synthetic meshwork (MESH), with or without heparin or sodium hyaluronate amendment. MATERIALS AND METHODS: Eighteen eyes of 18 rabbits received MESH surgery. The eyes were divided into three subgroups. Six eyes received the MESH implant with no modification (group 1), 6 eyes received MESH saturated with heparin (group 2), and 6 eyes received MESH with sodium hyaluronate administration into the anterior chamber during surgery (group 3). Intraocular pressure (IOP) and outflow facility were measured during a period of 6 months. RESULTS: The MESH-implanted eyes showed lower IOP and higher outflow facility than control eyes up to postoperative days 119 and 49, respectively (P > .05). Earliest functional failure was seen in group 3 and latest in group 2. CONCLUSION: MESH implant surgery showed a long-term efficacy in reducing IOP. The beneficial effects of added heparin were limited. Sodium hyaluronate administration reduced the efficacy of the implant device.

Animals↗
PubMed1997

Blebitis, early endophthalmitis, and late endophthalmitis after glaucoma-filtering surgery.

PURPOSE: The differentiating characteristics in blebitis and early and late endophthalmitis after glaucoma filtration surgery are reviewed. METHODS: All admission records and operative reports, as well as available office notes, on patients with blebitis or bleb-associated endophthalmitis admitted to a large referral eye center from 1985 to 1995 were reviewed retrospectively. RESULTS: Ten cases of blebitis and 33 cases of bleb-associated endophthalmitis were identified. One patient with blebitis progressed to culture-positive endophthalmitis. Of the 33 cases of bleb-associated endophthalmitis, there were 6 cases of early endophthalmitis (before postoperative week 6) and 27 cases of late endophthalmitis. In early endophthalmitis, Staphylococcus epidermidis was isolated on vitreous culture in 4 (67%) of 6 cases, whereas in late endophthalmitis, this organism was isolated in only 1 (4%) of 27 cases. In the 27 late cases, Streptococcus species and gram-negative organisms comprised 48% of isolates; of 33 cases of endophthalmitis, 15 (45%) demonstrated no growth on vitreous culture. Patients with endophthalmitis fared more poorly than those with blebitis in terms of visual outcome. CONCLUSIONS: Because blebitis may be prodromal to endophthalmitis, aggressive antimicrobial therapy, perhaps with oral quinolones, is warranted. In addition, patients with blebitis should be observed closely to identify extension into the vitreous cavity so that intravitreous antibiotics can be administered in a timely fashion. Finally, clinicians should not extrapolate the results of the Endophthalmitis Vitrectomy Study to the postfiltration surgery endophthalmitis given the differing pathogenesis and unique spectrum of organisms.

Adult↗
PubMed1995

Preoperative mitomycin-C subconjunctival injection and glaucoma filtering surgery.

Intraoperative mitomycin-C application has been well accepted recently as a useful adjunctive procedure to enhance the filtering effect in glaucoma surgery. However, the exact dose of mitomycin-C left after such a procedure in the ocular tissue is variable and unclear. It is important to determine such residual because of potential long-term toxicity of mitomycin-C to the eye. Based on previous successful experience using preoperative mitomycin-C subconjunctival injection in the THC-YAG laser sclerostomy on rabbits, the effect of intraocular pressure (IOP) control and its clinical observation was studied in six eyes of six refractory and high risk glaucoma patients by subconjunctival 1.2 micrograms to 3.6 micrograms mitomycin-C injection 24 to 72 hours prior to classic, routine, limbal-based trabeculectomy surgery. After 18 months of satisfactory clinical observation of the first eye for IOP, functioning bleb appearance and smooth clinical course, the same procedure was used on an additional five eyes, with a follow-up period of more than five months. Average IOP was reduced from 27.8 mm Hg (range 24 to 34 mm Hg) preoperatively to 9.5 mm Hg (range 5 to 14 mm Hg) postoperatively, with a smooth clinical course. The advantages of such preoperative subconjunctival mitomycin-C injection are emphasized here.

Adolescent↗
PubMed1998

A novel method for controlling the quantity of mitomycin-C applied during filtering surgery for glaucoma.

The use of a sponge impregnated with mitomycin-C is an increasingly common practice in glaucoma surgery. The appropriate antibiotic concentration and exposure time have been considered in the literature, but not the exact amount to be used or the size of the sponge. The purpose of this study was to estimate the quantity of mitomycin-C contained in sponges prepared by different surgeons as compared to that in applicators of the type used in Schirmer's test graduation (5 x 5 mm). Four surgeons each cut and prepared 10 sponges for intraoperative use according to their usual method. The same procedure was performed with 10 Schirmer's test graduations. Each sponge and each graduation was immersed in a solution of mitomycin-C 0.2 mg/ml, and the quantity of antibiotic (microg) in each was calculated as the difference between wet and dry weight. The mean quantity (+/- SEM) of mitomycin-C contained in cut sponges was 9.6 +/- 4.4 microg (range 1.9-17.3), and the differences between surgeons were statistically significant (p<0.0001). The mean quantity of antibiotic in Schirmer's test graduation was 1.7 +/- 0.3 microg (range 1.1-2.5), and the differences between surgeons were not statistically significant (p=0.79). The quantities of mitomycin-C contained in sponges prepared for glaucoma surgery differed for a given surgeon and between surgeons. Thus, variations in the doses applied to the sclera could account for certain complications due to mitomycin-C. The use of a Schirmer's test graduation improves predictability for the quantity of mitomycin-C applied to the sclera.

Antibiotics, Antineoplastic↗