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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↗
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↗
PubMed1997

[Does the dosage of mitomycin-C applied during filtering surgery of glaucoma vary with the individual surgeon?].

PURPOSE: 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). MATERIALS AND METHODS: 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 (microgram) in each was calculated as the difference between wet and dry weight. RESULTS: The mean quantity (+/-SEM) of mitomycin-C contained in cut sponges was 9.6 +/- 4.4 micrograms (range 1.9-17.3), and differences between surgeons were statistically significant (p < 0.0001). The mean quantity of antibiotic in Schirmer's test graduation was 1.7 +/- 0.3 micrograms (range 1.1-2.5), and the differences between surgeons were not statistically significant (p = 0.79). CONCLUSION: 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.

Antimetabolites↗
PubMed1994

The effects of glaucoma filtering surgery on the variability of diurnal intraocular pressure.

The results of this study indicate that filtration surgery reduces the mean diurnal IOP, the range of diurnal variation, and the day-to-day variability. The effect on the range is proportionally greater than on the other two parameters. Further study will be required to determine whether this selective effect makes surgical reduction of IOP any more effective in the prevention of further glaucomatous visual field damage than other therapeutic methods that lower mean IOP to the same degree.

Circadian Rhythm↗
PubMed2002

Free conjunctival autologous graft for bleb repair and bleb reduction after trabeculectomy and nonpenetrating filtering surgery.

PURPOSE: To describe methods and outcomes of excisional revision of a filtering bleb (bleb revision) using free conjunctival autologous graft either for bleb repair or for bleb reduction after trabeculectomy and deep sclerectomy with an implant. METHODS: Retrospective medical records were reviewed for a consecutive non-comparative case series comprising patients who underwent excisional revision of a filtering bleb between May 1998-January 2001. Excisional revision using free conjunctival autologous graft (bleb revision) was performed either for bleb repair, to treat early and late leaks and hypotony with maculopathy, or for bleb reduction, to improve ocular pain, discomfort, burning, foreign body sensation, tearing, and fluctuations of visual acuity. The revision consisted of bleb excision and free conjunctival autologous graft. The bleb histopathology was analyzed in patients who underwent bleb repair. RESULTS: Sixteen patients were included in the study, consisting of nine patients who had a trabeculectomy and seven patients who had a deep sclerectomy with an implant. Bleb revision was necessary in 14 patients due to leaking filtering bleb (bleb repair), and in 2 patients due to bleb dysesthesia (bleb reduction). After a follow-up of 15.1 +/- 8.4 months, the mean intraocular pressure (IOP) rose from 7.8 +/- 6.3 mm Hg to 14.3 +/- 6.5 mm Hg, and the visual acuity from 0.4 +/- 0.3 to 0.7 +/- 0.3, with a P value of 0.008 and 0.03, respectively. The complete success rate at 32 months, according to the Kaplan-Meier survival curve, was 38.3%, and the qualified success rate was 83.3%. Four patients (25%) required additional suturing for persistent bleb leak. To control IOP, antiglaucoma medical therapy was needed for six patients (37.5%) and repeated glaucoma surgery was needed for one patient. CONCLUSION: Free conjunctival autologous graft is a safe and successful procedure for bleb repair and bleb reduction. However, patients should be aware of the postoperative possibility of requiring medical or surgical intervention for IOP control after revision.

Adult↗
PubMed1998

Is the single use of intraoperative 5-fluorouracil in filtering surgery for high-risk cases enough?

PURPOSE: To study the efficacy of the adjunctive use of a single intraoperative application of 5-fluorouracil (5FU) in eyes with poor prognoses for a successful outcome with a trabeculectomy. METHOD: Twenty-four patients (25 eyes) with a mean age of 63.7 +/- 14.7 years (range 27-86 years) and a history of one or more risk factors (age < 50 years, more than 3 years on topical medication, a previous failed filter, previous cataract surgery, uveitis, neovascular glaucoma) underwent trabeculectomy with the intraoperative application of 5FU on a sponge (25 mg/ml) for 5 min. The average follow-up was 10.1 +/- 5.5 months. RESULTS: The mean pre-operative intraocular pressure (IOP) was 24.7 +/- 6.2 mmHg and the mean post-operative IOP was 13.9 +/- 3.5 mmHg. Success, defined as an IOP within desired target levels for a particular eye, in the presence of a functioning filter, without supplementary medical therapy, was achieved in 56.5% of cases. CONCLUSIONS: Our results of successful filters in this group of patients with moderate- to high-risk characteristics approach similar figures quoted for trabeculectomies without the adjunctive use of intraoperative 5FU in eyes with poor prognoses with a similar length of follow-up. Though the numbers are small there is a trend that indicates that the intraoperative application of a single dose of 5FU alone may not be sufficient in eyes with moderate- to high-risk characteristics of failure of a trabeculectomy.

Adult↗
PubMed1997

Effects of mitomycin C on the expression of proliferating cell nuclear antigen after filtering surgery in rabbits.

BACKGROUND: The aim of the study was to evaluate the effects of mitomycin C on the cell replication activity in wound healing following experimental filtration surgery. METHODS: Trabeculectomy with or without application of mitomycin C was performed on albino rabbit eyes. At 1, 4, 7, 14, and 28 days after surgery, the expression of proliferating cell nuclear antigen, a marker of cell proliferation, in the filtering site was examined immunohistochemically using a streptavidin-biotin complex method. RESULTS: In control eyes that underwent trabeculectomy but did not receive mitomycin C, the number of immunoreactive cells increased 4-7 days after operation and decreased markedly at around 14 days. The filtering site was obstructed histologically at 4-7 days after operation. In the mitomycin C-treated eyes, immunoreactive cells appeared 4 days after surgery but disappeared by 7 days at the surgical site. The number of immunoreactive cells in the treated eyes was much lower than that in control eyes. CONCLUSION: The cell replication activity was markedly inhibited by administration of mitomycin C. The filtering site remained open for 28 days after surgery, whereas it was completely obstructed within 7 days in control eyes. Immunocytochemistry for proliferating cell nuclear antigen, as used in this study, is a simple and reliable method for detection of cell replication activity.

Animals↗
PubMed1987

Internal sclerectomy for glaucoma filtering surgery with an automated trephine.

A technique is described for performing full-thickness glaucoma filtering operation from within the anterior chamber. The procedure utilizes an automated trephine, designated the "trabecuphine," that is capable of simultaneous cutting and irrigation. The trabecuphine is brought into the anterior chamber through a limbal incision 180 degrees away from the planned filter site. The trephine is passed across the anterior chamber, above the iris, and into the angle to perform the sclerotomy. This procedure was performed successfully in 13 eyes of seven cynomolgus monkeys. Complications included two small hyphemas that cleared completely. Other complications such as flat anterior chamber, corneal damage, iridodialysis, conjunctival buttonhole, and cataract formation did not occur. Internal scleral trephination may offer another alternative in the surgical management of patients with intractable glaucoma.

Animals↗
PubMed1986

Temporary visual loss with ciliary body detachment and hypotony after attempted YAG laser repair of failed filtering surgery.

Ciliary body detachment, hypotony, and visual loss developed within one month after an attempt to reopen a closed filtering bleb with YAG laser treatment. The patient was a 68-year-old black woman who had a previously functioning thermal sclerostomy. YAG laser energy delivered to the sclerosed filtering site ab interno was unsuccessful in restoring patency to the filtering site as judged by clinical examination. Because of hypotony, all glaucoma medications were discontinued. Resolution of the ciliary body detachment with return of vision and stable intraocular pressures occurred after three weeks of intensive topical and systemic corticosteroid treatment.

Aged↗