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Phacoemulsification combined with posterior capsulorhexis and anterior vitrectomy in the management of malignant glaucoma in phakic eyes

2012; Wiley; Volume: 91; Issue: 7 Linguagem: Inglês

10.1111/j.1755-3768.2012.02451.x

1755-3768

Xing Liu, Mei Li, Bing Cheng, Zhen Mao, Yimin Zhong, Dandan Wang, Dan Cao, Fenfen Yu, Nathan Congdon,

Retinal and Macular Surgery

Purpose: To describe sequential phacoemulsification–intraocular lens (IOL) implantation–posterior capsulorhexis–anterior vitrectomy in the management of phakic malignant glaucoma. Methods: Twenty consecutive patients (25 eyes) with phakic malignant glaucoma were enrolled at the Zhongshan Ophthalmic Center, Sun Yat-sen University. All patients underwent phacoemulsification, IOL implantation and posterior capsulorhexis together with anterior vitrectomy via a clear corneal paracentesis. Visual acuity, intraocular pressure (IOP), anterior chamber depth (ACD), surgical complications and medications required after the surgery were recorded. Results: After surgery, the mean LogMAR visual acuity and ACD increased significantly (visual acuity from −1.56 ± 1.17 to −0.54 ± 0.81, p < 0.001; ACD from 0.367 ± 0.397 mm to 2.390 ± 0.575 mm, p < 0.001), and mean IOP decreased significantly (from 39.6 ± 10.6 mm Hg to 14.5 ± 4.1 mmHg, p < 0.001). No serious perioperative complications occurred, and only five eyes required topical glaucoma medications after surgery. Conclusion: Combined phacoemulsification–IOL implantation–posterior capsulorhexis–anterior vitrectomy surgery is a safe and effective method for treating patients with phakic malignant glaucoma. Malignant glaucoma continues to be among the most challenging problems faced by ophthalmologists. It typically arises following filtration surgery in eyes with angle-closure glaucoma. This form of glaucoma is characterized by central and peripheral shallowing of the anterior chamber with the absence of suprachoroidal effusion or haemorrhage, despite the presence of a patent iridotomy (Epstein 1997). The intraocular pressure (IOP) is often markedly increased, but may be normal initially. Malignant glaucoma develops in 2–4% of phakic patients treated surgically for angle-closure glaucoma (Luntz & Rosenblatt 1987; Quigley et al. 2003). The onset of the condition may occur at any time following surgery, from the first postoperative day to many years later. Intensive medical management, including topical cycloplegics, aqueous suppressants and hyperosmotic agents, is advocated as the initial treatment for malignant glaucoma. Approximately, 50% of patients will respond to medical therapy within 4–5 days (Simmons et al. 1985). If patients do not respond to medical treatment, surgical intervention may be required. Direct argon laser through a peripheral iridectomy may be used in an attempt to shrink the ciliary processes. Herschler (1980) reported success in five of six eyes treated in this manner, Alternatively, in aphakic or pesudophakic eyes, the neodymium/yttrium-aluminium-garnet (Nd:YAG) laser may be used to perform posterior capsulotomy/hyaloidotomy (Melamed et al. 1991; Halkias et al. 1992). Although encouraging results have been reported, this procedure is often not easy to perform and may require several attempts. Patients who do not respond to conservative treatment often require pars plana vitrectomy to reduce the vitreous volume, normalize aqueous flow and achieve sustained control of IOP (Ruben et al. 1997). This procedure is successful in pseudophakic or aphakic eyes, but a high rate (50%) of recurrent or persistent malignant glaucoma and postoperative cataract formation has been reported in phakic eyes, which leads to consideration of lensectomy (Bynes et al. 1995). Previous studies have proven the effectiveness of vitrectomy combined with lensectomy in the treatment of malignant glaucoma (Harbour et al. 1996; Sharma et al. 2006). However, the visual acuity is likely to be poor because of the difficulty of IOL implantation after complete removal of the lens capsule and zonular fibres (Harbour et al. 1996; Lois et al. 2001; Sharma et al. 2006). In the current report, we describe a novel surgical approach for the management of phakic malignant glaucoma. A series of patients with malignant glaucoma undergoing combined sequential phacoemulsification–IOL implantation–posterior capsulorhexis–anterior vitrectomy through a clear corneal incision were followed and evaluated to determine the efficacy and safety of this approach. This study was conducted on 20 patients (25 eyes) presenting to the Glaucoma Service of the Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China, between November 2004 and December 2009. Among 20 patients (25 eyes) enrolled in the study, 16 patients (19 eyes) were women (75.0%), and the mean age was 53 ± 14 years (median: 55 years; range: 23–75 years). All patients underwent intensive medical therapy (including topical cycloplegics, aqueous suppressants and hyperosmotic agents) for at least 7 days prior to consideration of surgery. Study procedures were in accordance with the tenets of the Declaration of Helsinki, and the Ethics Committee of Sun Yat-sen University approved the protocol in its entirety. All patients provided written informed consent. The diagnosis of malignant glaucoma was made on the basis of the following criteria (Epstein 1997; Ruben et al. 1997): (i) extremely shallow or flat central and peripheral anterior chamber; (ii) presence of a patent iridotomy or iridectomy (ruling out a pupillary block mechanism); (iii) absence of suprachoroidal effusion/haemorrhage or other posterior segment mass by indirect ophthalmoscopy and/or echography. The following data were collected for each patient: age, sex, laterality of surgery, primary ophthalmic diagnosis before malignant glaucoma, previous ocular procedures, axial length (AL), preoperative and postoperative best-corrected visual acuity (BCVA), IOP, anterior chamber depth (ACD), surgical complications and length of postoperative follow-up. Axial length was obtained by A-scan ultrasonography (Storz CompuScan; Storz, St Louis, MO, USA), and ACD was measured by ultrasound biomicroscopy (UBM Plus, Model P45; Pardigm Medical Industries, Salt Lake City, UT, USA). After the combined surgical procedure, all patients underwent examination at 3 days, 1 week and 1 month postoperatively, and at non-standardized intervals thereafter. The ACD was measured by anterior segment coherence tomography (AS-OCT, VisanteTM; Carl Zeiss Meditec, Dublin, CA, USA) after surgery. All surgical procedures were performed by two experienced surgeons (XL, BC). A 3.2-mm-wide, 1.5-mm-long clear corneal tunnel was created at 2–3 o'clock in a left eye and 8–9 o'clock in a right eye, and a second 0.6-mm to 0.8-mm-wide corneal tunnel was made at 6 o'clock in a left eye and 12 o'clock in a right eye. The anterior chamber was deepened with viscoelastic agent (Duovisc; Alcon, Fort Worth, TX, USA). Extra steps, such as sphincterotomies and posterior synechiolysis, were performed as necessary to maximize visualization prior to carrying out a 5.0-mm continuous curvilinear capsulorhexis. Bimanual phacoemulsification and cortex removal were performed. In all cases, a foldable single-piece posterior chamber IOL (Acrysof SA60AT; Alcon) was inserted into the capsular bag. Viscoelastics was left in the anterior chamber. After IOL implantation in the capsular bag, a thin film of viscoelastic agent was injected in the posterior chamber, behind the IOL, causing the IOL to tilt anteriorly at its superior edge. Posterior capsulorhexis was performed under high magnification with the tip of a standard 25-gauge bent cystotome. An infusion cannula was placed in the posterior chamber through a clear corneal paracentesis, a flow of balanced salt solution was started and the anterior vitreous was excised. Care was taken to introduce and maintain the cutter port facing the centre of the vitreous cavity and to direct it away from the retina to prevent damage. In every case, the anterior chamber deepened visibly during vitrectomy. Remaining viscoelastic agent was removed completely by irrigation and aspiration. Subconjunctival injections of antibiotic and steroid were given at the end of surgery (1, 2). After IOL implantation in the capsular bag, a thin film of viscoelastic was spread inferior to the IOL, causing the IOL to tilt anteriorly and superiorly. Posterior capsulorhexis with the tip of standard 25-gauge cystotome was performed. Infusion cannula was placed in the posterior chamber through clear corneal paracentesis, and a flow of balanced salt solution was started and then, the anterior vitreous was excised. Postoperatively, intravenous steroid (80 mg prednisolone) was given once a day for 5–7 days, and topical medication was administered as follows: atropine 1% twice daily, levofloxacin 0.3% four times daily and prednisolone acetate 1% six times daily for 4–6 weeks. The primary ophthalmic diagnosis prior to the occurrence of malignant glaucoma was chronic angle-closure glaucoma (CACG) in 20 eyes (80.0%) and acute angle-closure glaucoma in five eyes (20.0%). One patient had undergone prior peripheral iridectomy; all other subjects had had uneventful filtration surgery with limbal-based conjunctival flaps (5 with mitomycin C) before the occurrence of malignant glaucoma. Seven eyes had undergone anterior chamber reformation after the onset of malignant glaucoma (Table 1). At the time of diagnosis of malignant glaucoma, the mean IOP was 39.6 ± 10.6 mm Hg (median: 38.0 mm Hg; range: 22.0–60.0 mm Hg) and the mean LogMAR BCVA was −1.56 ± 1.17 (median: −1.61; range: −4.61 to −0.22). The visual acuity of three eyes was hand motion and of two eyes was counting fingers. The mean ACD was 0.367 ± 0.397 mm (median: 0.400 mm; range: 0–1.360 mm), with grade 3 flat anterior chamber (Shaffer Grade System) (Shaffer 1960) in 10 eyes. The mean AL was 21.91 ± 0.81 mm (median: 21.93 mm; range: 20.31–23.30 mm), and the mean follow-up time was 23.1 ± 15.8 months (median: 15 months; range: 8–50 months) (Table 1). Significant pre- and postoperative differences were noted in BCVA, IOP and ACD (p < 0.001 for all). Postoperatively, the mean IOP decreased to 14.5 ± 4.1 mm Hg (median: 16.0 mm Hg; range: 8.0–25.0 mm Hg). Only five eyes required topical glaucoma medications after surgery (Table 1, 3, 4). The mean logMAR BCVA improved to −0.54 ± 0.81 (median: −0.51; range: −2.30 to 0.18). The mean ACD increased to 2.39 ± 0.58 mm (median: 2.200 mm; range: 1.590–3.790 mm; mean increase 1.845 mm). No serious complications such as corneal decompensation, retinal detachment or suprachoroidal haemorrhage were observed. Failure of a pre-existing filtering bleb occurred in five eyes (20.8%, 5/24). Anterior segment slit lamp photograph of the right eye of a 55-year-old woman with phakic malignant glaucoma (Patient 2). The image on the left shows marked iris–corneal touch and anterior chamber flattening because of malignant glaucoma. The right image shows significant anterior chamber deepening following phacoemulsification, IOL implantation, posterior capsulorhexis and anterior vitrectomy. Anterior segment images of the right eye of a 55-year-old woman with phakic malignant glaucoma (Patient 2). (A) Ultrasound biomicroscopic (UBM) image at the time of diagnosis with malignant glaucoma shows marked iris–corneal touch, anterior chamber flattening [anterior chamber depth (ACD) = 0.400 mm] and forward displacement of the iris–lens diaphragm. (B) Anterior segment coherence tomography (AS-OCT) image after phacoemulsification, IOL implantation, posterior capsulorhexis and anterior vitrectomy. The anterior chamber has deepened (ACD = 3.390 mm), and the iris–lens diaphragm has moved backward. The precise pathophysiology of malignant glaucoma is not completely understood. Shaffer (1954) (Simmons et al. 1989) proposed misdirection of aqueous either into or around the vitreous. This theory postulates an abnormal anatomical connection among the lens, zonules, anterior vitreous face and ciliary body, which causes a misdirection of aqueous fluid into the vitreous cavity. This subsequently leads to an increase in vitreous volume, anterior displacement of central and peripheral anterior segment structures, and an increase in IOP. But Quigley et al. (2003); Quigley (2009) proposed that aqueous does not flow backward, nor does the ciliary body block flow. Rather, it is the expansion of choroidal volume, which leads to increased vitreous cavity pressure and compression of an already condensed vitreous body, thereby impeding free fluid transit within and through the vitreous. Although there is no general agreement on the underlying mechanism of this disease, the principal of treatment is generally understood to be removal of some or all of the anterior vitreous body to restore the normal aqueous flow into the anterior chamber (Epstein 1997; Ruben et al. 1997; Quigley et al. 2003). Previous reports have shown that pars plana vitrectomy is an effective surgical means for treating malignant glaucoma in phakic, pseudophakic and aphakic eyes (Harbour et al. 1996; Sharma et al. 2006). However, even after pars plana vitrectomy, a higher rate of persistence or recurrence of malignant glaucoma is observed in phakic eyes not undergoing lensectomy compared with pesudophakic eyes and those receiving lensectomy. In a review of 21 eyes requiring surgical treatment at Moorfields Eye Hospital, pars plana vitrectomy alone was successful in 67% (4/6) of pesudophakic, but only 25% (1/4) of phakic eyes. Extracapsular cataract surgery combined with vitrectomy with intact posterior capsule had a success rate of 17% (1/6), whereas in patients in whom a primary posterior capsulotomy was performed, the success rate was 83% (5/6) (Tsai et al. 1997). Phakic eyes present a greater challenge. The presence of an intact lens may decrease the likelihood of successful restoration of normal aqueous flow. In addition, in phakic eyes, excision of the anterior vitreous without incurring lens damage may be complicated because visualization of this area can be difficult or impossible. For these reasons, combined lens extraction and vitrectomy offers a theoretical advantage in treating phakic malignant glaucoma. Although pars plana vitrectomy combined with lensectomy has shown modest to good success rate in treating phakic malignant glaucoma, IOL implantation has not usually been performed at the time of surgery, which limits visual acuity in this setting (Bynes et al. 1995; Harbour et al. 1996; Sharma et al. 2006). This points to combined lens extraction–vitrectomy–IOL implantation as an optimal surgical treatment for phakic malignant glaucoma. Pars plana vitrectomy requires vitreoretinal surgical expertise and thus is not usually performed by glaucoma surgeons. Anterior vitrectomy via corneal or corneoscleral paracentesis is a much simpler way to remove the anterior vitreous body compared with pars plana vitrectomy. In a previous study, Lois et al. (2001) reported a combined zonulectomy–capsulectomy–anteriorvitrectomy surgery through the pre-existing iridectomy/iridotomy via the anterior chamber in five pseudophakic eyes with malignant glaucoma. Resolution of the malignant glaucoma was achieved in all cases, and no recurrences were observed. However, it is difficult to achieve the same communication without damaging the crystalline lens in phakic eyes. And partial or complete excision of the zonules may limit the ability to implant an IOL in the bag with optimum stability. So, finding a new surgical approach for malignant glaucoma, which can decrease the complications occurred in pars plana vitrectomy or combined zonulectomy–capsulectomy–anteriorvitrectomy surgery and improve the visual acuity at the same time, would be the best choice for patients. In this study, we report a novel approach that includes combined phacoemulsification, IOL implantation–posterior capsulorhexis and anterior vitrectomy through a corneal incision. All 25 phakic eyes with malignant glaucoma in our study resolved after the combined operation, and no recurrences were observed over a mean 23 months of follow-up. Visual acuity was greatly improved or remained stable in 22 eyes. Serious perioperative complications after pars plana vitrectomy reported previously, including corneal decompensation, suprachoroidal haemorrhage and choroidal or retinal detachment, were not observed in our series. Failure of a pre-existing filtering bleb occurred in five eyes (20.8%, 5/24), but the IOP could be controlled with antiglaucoma medications, and none of these patients needed further surgical therapy. Our proposed combined surgical procedure has several advantages. Firstly, it is effective in treating malignant glaucoma in phakic eyes because it can break iridolenticular, ciliolenticular, iridovitreal and ciliovitreal blocks at the same time, and it establishes an unimpeded pathway for aqueous flow from the vitreous chamber into the anterior chamber. Secondly, lens extraction and anterior vitrectomy can be performed via the same sutureless corneal incision by a glaucoma surgeon not trained in pars plana vitrectomy techniques. Thirdly, posterior IOL implantation can be performed at the time of the surgery, which helps to improve postoperative visual acuity. The procedure appears to be safe, except for potential adverse effects on the conjunctival filtering bleb. Fourthly, the main part of the posterior capsule and the zonules is preserved, which enables a stable endocapsular placement of the IOL. Based on our experience in managing this series of patients with extremely shallow anterior chamber, some surgical considerations should be emphasized. Quantitative evaluation of the number of corneal endothelial cells is usually impossible in eyes with malignant glaucoma because of near or full apposition between the endothelium and lens–iris diaphragm. Choosing a high-viscosity viscoelastic is therefore important to prevent damage to these cells. For the same reason, high ultrasonic energy should be avoided during surgery. Hyperosmotic agents such as mannitol should be given intravenously prior to surgery, to increase the likelihood of successful intra-operative reformation of the anterior chamber. The curvilinear capsulorhexis should not exceed 5 mm in diameter, because patients with malignant glaucoma have often been treated with cycloplegics prior to surgery; so a relatively small capsulorhexis can prevent prolapse of the IOL from the capsular bag and incarceration in the pupil. In summary, the safety and utility of combined phacoemulsification, IOL implantation, posterior capsulorhexis and anterior vitrectomy via an anterior segment approach make this procedure an attractive therapeutic option for glaucoma surgeons in cases of phakic eyes with malignant glaucoma that do not respond to more conservative treatments. This study was supported by Guangdong Provincial Natural Science Grant Number 2011010006046. None of the authors have any proprietary or commercial interest in any of the materials discussed in this article.