Complications of glaucoma drainage implant surgery

Glaucoma drainage implants play an important role in the management of refractory glaucoma. It may be considered as a primary procedure in eyes with severe scarring of the conjunctiva and the limbus, neovascularization, multiple previous, failed filtering procedures, and severely glaucomatous eyes for which corneal graft is planned. Recommendations have been made regarding improving the biocompatibility of the materials used in the manufacture of these implants. The current state of development of glaucoma drainage implants is likened to that of intraocular lenses in the 1970s. Further development of devices and techniques will only serve to improve our armamentarium and success against glaucoma, specifically refractory glaucoma. Glaucoma posterior tube shunts have proved to be safe, with the majority of complications either nonsight-threatening, spontaneously resolving, or reversible. Considered primarily in the most severe cases of refractory glaucoma, it has otherwise changed the outlook for such patients.     

Recent developments in glaucoma drainage implant surgery

Refractory glaucoma remains a challenging problem for the ophthalmologist. Drainage implant surgery is a valuable and effective option for its treatment. Recent developments in implant design and surgical technique have decreased the incidence and severity of postoperative complications while increasing the efficacy of glaucoma drainage implant devices.     

Outcomes of inferonasal Baerveldt glaucoma drainage implant surgery

PURPOSE: To determine the outcomes of inferonasal Baerveldt glaucoma implant (BGI) surgery. PATIENTS AND METHODS: A retrospective, non-comparative case series of 182 eyes of 182 patients who underwent inferonasal placement of a Baerveldt glaucoma implant. The main outcome measures included intraocular pressure, number of glaucoma medications, best corrected visual acuity, and complications. RESULTS: Patients were followed for an average (+/- SD) of 19 +/- 15 months. Median Snellen visual acuity was unchanged at last follow-up. Intraocular pressure was reduced from a mean (+/- SD) of 28.6 +/- 11.5 mm Hg preoperatively to 13.4 +/- 5.7 mm Hg at most recent follow-up (P < 0.001). The number of antiglaucoma medications was reduced from a mean (+/- SD) of 2.7 +/- 1.3 preoperatively to 1.1 +/- 1.1 at most recent follow-up. Nineteen eyes met our criteria for failure, yielding a cumulative percent survival of 92% at 12 months, 88% at 24 months, and 77% at 44 months. The most common complications were hyphema (14 eyes, 8%), choroidal effusion (12 eyes, 7%), and corneal decompensation (19 eyes, 10%). Endophthalmitis and diplopia occurred rarely (1 eye, <1%; 3 eyes, 2%, respectively). CONCLUSIONS: Inferonasal Baerveldt glaucoma implant placement appears to be a safe and effective surgical option that may be helpful in certain clinical situations.     

A comparison of glaucoma drainage implant tube coverage

PURPOSE: Surgeons may use various materials, including donor sclera, dura, or pericardium grafts to cover glaucoma drainage implant tubes, prior to repositioning conjunctiva. We reviewed our experience with these materials. PATIENTS AND METHODS: Sixty-four eyes with at least 24 months follow-up status post glaucoma drainage implant surgery were evaluated for signs of tube erosion, as well as patch graft thinning, after initial placement of donor sclera (23), dura (18), or pericardium (23) patch grafts. RESULTS: Sixty-two eyes required no intervention for conjunctival and patch graft melting with subsequent tube erosion. Three cases (two eyes) of erosion requiring reoperation (1-dura at 6 months, 1-sclera at 15 months, and in the same eye 21 months later, 1-pericardium) were noted. Significant thinning of the donor patch graft such that the tube was visible beneath intact conjunctiva ocurred in 6 out of 23 donor sclera eyes, 4 out of 18 donor dura eyes, and 6 out of 23 donor pericardium eyes. CONCLUSION: No material was more prone to melting than another. Donor sclera may be slightly more cost-efficient, but gamma-irradiated pericardium has sterility advantages.     

Biocompatibility of the Ex-PRESS miniature glaucoma drainage implant

PURPOSE: Based on lessons learned from earlier attempts, a novel miniature glaucoma implant, Ex-PRESS, was developed in 1998. The current study summarizes the histopathologic evaluation of this device implanted in the eyes of rabbits. METHODS: The device was implanted into the anterior chamber at the corneoscleral junction in 1 eye each of 8 white New Zealand rabbits, while the contralateral eye served as control. Three and 6 months after implantation, the rabbits were killed and their eyes were enucleated and processed histologically, leaving the device in situ when sectioning. RESULTS: Three and 6 months postoperatively, the local tissue reaction typically consisted of an enveloping, thin, mature, fibrotic capsule (thickness <0.04 mm), devoid of inflammatory cells. This capsule surrounded approximately 25% of the implant surface area present in the sections. The lumina of the devices were devoid of inflammatory exudates or other obstructions in all specimens examined, suggesting free flow of fluid. CONCLUSIONS: The implantation of the Ex-PRESS miniature glaucoma shunt resulted in minimal capsular reaction. Considering the high reactivity of the rabbit eye, it is possible that this implant will induce a smaller cellular inflammatory reaction in the human eye.     

Long-term results of non-valved Glaucoma drainage implant surgery and glaucoma drainage implant combined with trabeculectomy

Purpose:

The purpose was to investigate the efficacy and complications of nonvalved glaucoma drainage implant (GDI) surgery and GDI combined with trabeculectomy.

Subjects and Methods:

Serial Japanese patients who received GDI were retrospectively investigated. The survival rate of eyes was analyzed using the Kaplan-Meier method, defining death as: (1) Intraocular pressure (IOP) <6 mmHg, or ≥22 mmHg, and <20% reduction of preoperative IOP, (2) additional glaucoma surgery, (3) loss of light perception. Prognostic factors of age, sex, previous surgery, type of glaucoma, synechial closure, preoperative IOP, type of GDI (single-, double-plate Molteno, Baerveldt 350) and GDI combined with trabeculectomy were investigated employing proportional hazards analysis.

Results:

One hundred and twenty-four eyes of 109 patients aged 53.3 ± 7.8 years old were analyzed. Types of GDI were single-plate (15.3%), double-plate Molteno (71.8%), and Baerveldt 350 (12.9%). The results of survival rate analysis were 86.1, 71.1, 71.1, and 64.6% for 1, 3, 5, and 10 years respectively. Thirty-four eyes (27.4%) died because of uncontrolled IOP (19.4%), loss of light perception (5.6%), and additional glaucoma surgery (2.4%). Single-plate Molteno was the only risk factor for failure. Persistent unphysiological hypotony (0.8%) and bullous keratopathy (5.6%) were observed.

Conclusion:

Nonvalved GDI surgery and GDI combined with trabeculectomy using nonabsorbable tube ligature proved to be an excellent device for any type of glaucoma in Japanese patients. Hypotony and corneal endothelial loss are the most serious complication in the long-term results of our patients.     

Sequential or simultaneous cyclophotocoagulation and glaucoma drainage implant for refractory glaucoma

PURPOSE: To describe the outcomes of combining cyclophotocoagulation and tube-shunt glaucoma drainage implants, either sequentially or simultaneously, for the control of refractory glaucomas. PATIENTS AND METHODS: A retrospective review was conducted of all patients that had been treated at our institute with both cyclophotocoagulation and a tube-shunt glaucoma drainage implant in the same eye between January 1996 and June 2000. Preoperative and postoperative intraocular pressure, number of glaucoma medications, vision, and complications data were collected for each eye. RESULTS: A total of 10 eyes of 9 patients met the study criteria. The minimum follow-up period after the last surgery was 15 months. Intraocular pressures were reduced from 28.5 +/- 7.2 mm Hg preoperatively to 13.9 +/- 5.4 mm Hg postoperatively at 15 months (P < 0.000, n = 9). Medications were reduced from 2.7 +/- 1.2 preoperatively to 0.3 +/- 0.5 postoperatively at 15 months (P < 0.000, n = 9). Of the eight eyes with measurable Snellen acuity, postoperative vision decreased two or more lines in five eyes (63%). Complications included transient hypotony (one eye), transient serous choroidal detachment (two eyes), cystoid macular edema (two eyes), corneal edema (three eyes), and panuveitis with chronic hypotony and traction retinal detachment (one eye). CONCLUSIONS: Combining cyclophotocoagulation with tube-shunt glaucoma drainage implants can effectively reduce intraocular pressure and number of glaucoma medications needed to achieve target intraocular pressure goals. Further study is needed to determine the safety of this combined approach compared with other available options to manage refractory glaucomas.     

The Ahmed drainage implant in the treatment of pediatric glaucoma

PURPOSE: To report the safety and efficacy of Ahmed Glaucoma Valve (New World Medical, Inc., Rancho Cucamonga, California, USA) implantation for the management of pediatric glaucoma in the early and intermediate follow-up period. DESIGN: Consecutive interventional case series. METHOD: A retrospective chart review was conducted on 60 eyes (44 patients, age range at surgery 1.5 months to 16 years, average 6 +/- 4.9 years), with pediatric glaucoma that underwent Ahmed Glaucoma Valve implantation for medically uncontrolled intraocular pressure (IOP) between the years 1995 and 2000. Outcome measures were control of IOP below 21 mm Hg, the need for antiglaucoma medications after surgery, and loss of 2 or more lines of Snellen acuity. Complications were monitored. RESULTS: The postoperative follow-up period for each eye averaged 24.3 +/- 16 months (range, 3 to 60 months). At last follow-up, IOP was controlled in 44 eyes (73%), 11 of which did not need antiglaucoma therapy. Kaplan-Meier life-table analysis showed probability of success with or without medications of 93% (95% confidence interval [CI], 86%-100%), 86% (95% CI, 77%-96%), 71% (95% CI, 59%-87%), and 45% (95% CI, 28%-80%) after 12, 24, 36, and 48 months of follow-up. Average IOP decreased from 32.8 +/- 6.2 before surgery to 16.6 +/- 8.0 postoperatively (P <.0001). The average number of medications used decreased from 4.4 +/- 1.97 to 2.0 +/- 2.0 (P <.0001). Kaplan-Meier survival analysis did not reveal any difference in survival profiles related to specific diagnosis of glaucoma, age (above or below 18 months), or prior surgery. Complications occurred in 30 eyes (50%). Although most resolved or were treated successfully, four patients had severe visual loss during the follow-up. Uveitis was a significant risk factor for tube exposure (Fisher exact test, P =.006). CONCLUSIONS: Ahmed Glaucoma Valve implantation is an effective treatment for pediatric glaucoma, although patients frequently require antiglaucoma medications. However, a high rate of potentially sight-threatening postoperative complications warrants ongoing close follow-up.     

Combined pars plana vitrectomy and glaucoma drainage implant placement for refractory glaucoma

PURPOSE:To report visual acuity and intraocular pressure outcomes among patients who have undergone combined pars plana vitrectomy and placement of a glaucoma drainage implant.METHODS:The medical records of all patients who underwent combined pars plana vitrectomy and placement of a glaucoma drainage implant at the Bascom Palmer Eye Institute by one of the authors between January 1, 1990, and February 28, 1998, were reviewed. Forty patients (40 eyes) were identified, including 14 patients with neovascular glaucoma secondary to proliferative diabetic retinopathy or central retinal vein occlusion, 15 patients with other posterior segment disease, seven patients with secondary angle-closure glaucoma, and four patients with aphakia with ruptured anterior hyaloid face. Main outcome measures included visual acuity and intraocular pressure at 1 year postoperatively.RESULTS:At 1 year postoperatively, 31 (77.5%) of 40 patients had stable or improved visual acuity; three eyes (7. 5%) had a final visual acuity of no light perception and three additional eyes (7.5%) were enucleated (because of chronic pain in two eyes and endophthalmitis in one eye). Mean preoperative intraocular pressure was 34 mm Hg and the median number of preoperative antiglaucoma medications was two. At 1 year postoperatively, mean intraocular pressure was 13 mm Hg and the median number of antiglaucoma medications was zero. Twenty-two patients (55.0%) achieved an intraocular pressure greater than 5 mm Hg and less than or equal to 21 mm Hg without antiglaucoma medication, and an additional seven patients (17.5%) achieved this level of intraocular pressure control with medication. Only one patient (2.5%) underwent further glaucoma surgery for uncontrolled intraocular pressure.CONCLUSIONS:Although combined pars plana vitrectomy and placement of a glaucoma drainage implant is often a successful management option in selected patients with refractory glaucoma, visual outcome may be poor because of severe underlying ocular disease and postoperative complications.     

Spontaneous extrusion of a stainless steel glaucoma drainage implant (Ex-PRESS)

PURPOSE: To report a case of spontaneous extrusion of a stainless steel glaucoma drainage implant (Ex-PRESS). METHODS: An Ex-PRESS was implanted under the conjunctiva in a 76-year-old man with primary open-angle glaucoma. RESULTS: Two years after implantation, the Ex-Press extruded spontaneously. Despite this adverse event, there was no increase in intraocular pressure. CONCLUSIONS: This is the first report of spontaneous extrusion of an Ex-PRESS device. Implanting the device under a scleral flap should be considered to avoid adverse events such as extrusion or conjunctival erosion.     

青光眼引流阀植入联合视网膜激光光凝治疗新生血管性青光眼

目的观察青光眼引流阀植入联合视网膜激光光凝治疗新生血管性青光眼的临床疗效。方法回顾性分析2007年6月至2010年6月在我院眼科确诊并行青光眼引流阀植入联合视网膜激光光凝治疗的新生血管性青光眼患者27例(27眼),记录术前、术后1周、1a的眼压、视力、并发症等,并检测患者视野、角膜内皮细胞丢失及滤过泡情况。结果 27例患者一次手术成功率为100.0%;术后1周,完全成功率55.6%,部分成功率为29.6%;术后1a完全成功率48.1%,部分成功率33.3%。术前平均眼压为(50.2±10.3)mmHg(1kPa=7.5mmHg),术后1周平均(13.0±8.6)mmHg,术后1a平均(14.1±7.9)mmHg,与术前相比差异均具有显著统计学意义(均为P<0.01)。术后1周视力有所提高者15例,不变者12例;术后1a视力有所提高者17例,不变者10例。术前角膜内皮细胞计数平均2328.5mm-2,术后1周为2298.7mm-2,与术前相比差异无统计学意义(P>0.05);术后1a平均为2009.2mm-2,与术前相比差异有统计学意义(P<0.05),术后1a角膜内皮丢失率为13.8%。早期术后并发症有滤过作用过强、前房出血等,所有患者未见引流管口暴露、角膜内皮失代偿等并发症发生。结论青光眼引流阀植入联合视网膜激光光凝治疗新生血管性青光眼疗效确切,可以有效控制眼压,并降低术后并发症的发生,是一种治疗新生血管性青光眼的理想方法。     

Combined Baerveldt glaucoma drainage implant and trabeculectomy with mitomycin C for refractory glaucoma

PURPOSE: To describe the surgical technique and clinical outcomes of a procedure for refractory glaucoma, concurrent Baerveldt glaucoma implant (BGI) and trabeculectomy with mitomycin C. MATERIALS AND METHODS: Medical records of all patients who underwent combined Prolene-ligated BGI and trabeculectomy with mitomycin C were retrospectively reviewed. Main outcome measures were intraocular pressure (IOP), number of glaucoma medications, visual acuity, and complications. Kaplan-Meier survival analysis was used to determine success, defined as IOP < 22 mm Hg, no reoperation for glaucoma, and no loss of light perception vision. RESULTS: The mean +/- SD follow-up period for 38 eyes of 36 patients was 34 +/- 36 months (range, 3-121 months), during which 18 of 38 eyes (47%) required laser suture lysis of the Prolene suture. Intraocular pressure was reduced from a mean (+/- SD) preoperative value of 35.7 +/- 12.8 to 12.7 +/- 4.7 mm Hg at 1-year follow-up and 11.9 +/- 5.5 mm Hg at the last follow-up visit ( < 0.001). Number of medicines used for glaucoma was reduced from a mean +/- SD preoperative value of 2.5 +/- 0.9 to 0.5 +/- 0.6 at 1-year follow-up and 0.6 +/- 0.8 at the last follow-up visit ( < 0.001). LogMar visual acuity remained stable at mean of 1.15 +/- 0.85 preoperatively, compared with 1.14 +/- 1.05 at 1-year follow-up, but declined to 1.61 +/- 1.01 at the last follow-up visit, a loss of an average of four lines of vision ( = 0.004). Cumulative success was 91% at year 1, 86% at year 2, and 81% at year 3. Three eyes (8%) had suprachoroidal hemorrhages, one eye (3%) needed reoperation for an extruded implant, one (3%) eye had poor vision due to chronic hypotony, three eyes (8%) required additional glaucoma surgery during the postoperative period, and one eye (3%) needed revision of the implant for pressure control. CONCLUSIONS: Combined BGI and mitomycin C trabeculectomy provides excellent postoperative IOP control in patients with refractory glaucoma.     

Combined phacoemulsification and Ahmed valve glaucoma drainage implant: a retrospective case series

PURPOSE: To report on the efficacy and safety of combined phacoemulsification and an Ahmed valve glaucoma drainage implant with respect to visual acuity improvement, intraocular pressure (IOP) control, and requirement for antiglaucoma medication. METHODS: A retrospective chart review was conducted of 41 eyes (31 patients) with coexisting visually significant cataracts and uncontrolled glaucoma who had combined phacoemulsification and Ahmed valve implantation. The outcome measures were: visual acuity, IOP, antiglaucoma medication requirements, and intra- and post-operative complications. Success was categorized as absolute (IOP<21 mmHg without the need for antiglaucoma medication) and relative (IOP<21 mmHg with one or more antiglaucoma medications). Failure was considered to be an IOP<6 mmHg or IOP>21 mmHg on maximally tolerated medications or any devastating complication. RESULTS: The mean patient age was 67.3+/-5.9 years old. The mean visual acuity improved from 0.73+/-0.5 to 0.16+/-0.16 (p=0.000). The mean IOP decreased from 28.2+/-3.1 to 16.8+/-2.1 (p=0.000, 40.4%), while the number of antiglaucoma medication decreased from 2.6+/-0.66 to 1.2+/-1.4 (p=0.000). The absolute and relative success rates were 56.1% and 31.7%, respectively; 5 eyes (12.2%) were considered failures. There were no intraoperative complications; postoperative complications occurred in 8 eyes (19.5%). A hypertensive phase was detected in 12 (29.3%) eyes. CONCLUSIONS: Combined phacoemulsification and Ahmed valve glaucoma drainage implantation is a safe and effective alternative to phacotrabeculectomy in patients with coexisting cataract and refractory glaucoma.