Surgery For Proliferative Diabetic Retinopathy Research Articles

Surgery for Proliferative Diabetic Retinopathy: New Tips and Tricks.

Over the recent years, retina specialists have enjoyed significant improvements in the surgical management of proliferative diabetic retinopathy including improved preoperative planning, vitreoretinal instrumentation and new surgical maneuvers. In this review, we present new tips and tricks such as preoperative pharmacotherapy approaches including pegaptanib injection and biodegradable dexamethasone implantation, bimanual vitrectomy techniques and the concept of mixing small gauges as well as valved cannulas and intraoperative optical coherence tomography. With advanced surgical planning and sophisticated operative maneuvers tailored to the individual patient, excellent outcomes can be achieved even in severe cases of diabetic tractional detachment.

Evaluation of proliferating cell abundance and phenotypes in proliferative diabetic retinopathy.

The aim of this work is to evaluate the abundance, origins, and phenotypes of actively proliferating cells in proliferative diabetic retinopathy (PDR). Eleven epiretinal membranes from patients undergoing surgery for PDR were evaluated by indirect immunofluorescence for evidence of cell proliferation using the nuclear cell proliferation marker Ki67 and for cell identities using glial fibrillary acidic protein (GFAP), glutamine synthetase, and α-smooth muscle actin (αSMA). Ki67 positivity was consistently rare in PDR epiretinal membranes at 3.02 ± 1.42% of the total cell population. The majority of the Ki67-positive cells were also positive for GFAP (74.0%) with lower proportions positive for αSMA (30.7%) and glutamine synthetase (1.5%). Co-localization studies using glial and myoid markers revealed that virtually all (92%) of the αSMA-positive cells are also GFAP positive and thus derive from glia. Entry into cell cycle and thus cell proliferation appears to be a rare phenomenon in PDR involving only a small percentage of the total cell population. Glia and/or glial-derived myofibroblasts appear to be the predominate cell types in epiretinal scar tissues and also account for the majority of the actively proliferating cells.

Comparison of combined and sequential surgery for proliferative diabetic retinopathy: a single surgeon study.

PurposeTo compare the results of combined and consecutive surgeries to treat proliferative diabetic retinopathy and cataract.MethodsRetrospective comparative study. Forty-one patients with proliferative diabetic retinopathy (PDR) were enrolled. Twenty-nine eyes for the combined surgery group and twelve eyes for the sequential group were included. All surgeries were performed by one surgeon. Phacoemulsification was performed using a clear cornea incision. The vitrectomy was performed using a 20-gauge vitreous cutter.ResultsThe best corrected visual acuity (BCVA) and intra- and post-operative complications were the main outcome measures. In the combined surgery group, the BCVA increased in 18 (62.1%) eyes, while eight (27.6%) eyes remained stable and three (10.3%) eyes decreased. Postoperative complications included fibrinous exudation in nine eyes, macular edema in three eyes and vitreous hemorrhage in three eyes. In the sequential surgery group, the BCVA increased in seven (58.3%) eyes, remained the same in four (33.3%) eyes and was reduced in one (8.3%) eye. Postoperative complications included macular edema in two eyes, neovascular glaucoma in two eyes and vitreous hemorrhage in one eye.ConclusionsBoth combined and sequential surgeries are safe and effective for treating PDR and cataracts. The combined surgery had a higher incidence of fibrinous exudation.

The clinical observation of combined surgery for proliferative diabetic retinopathy.

Objective To compare the effect of vitrectomy combined with pars plana lensectomy or phacoemulsification,intraocular lens implantation(combined vitrectomy),and pars plana vitrectomy alone on retinal disorders resulting from diabetic retinopathy.Methods The clinical data,vision,and complications of 32 patients(40 eyes)who underwent combined vitrectomy and 28 patients(33 eyes)who underwent vitrectomy alone retrospectively were analyzed.Results Final visual acuity were all improved in the two groups,which was achieved in 31 eyes in group of combined vitrectomy(77.50％),in 22 eyes in group of vitrectomy alone(66.67％).There were significant difference between them(x2 =4.74,P ＜0.05).Five eyes with preoperative iris neovascularization was completely fade away within 1-2 months in combined vitrectomy group,while only 1 eye in vitrectomy alone group.Nine eyes were found postoperative fibrin formation in combined vitrectomy group and only 1 eye in vitrectomy alone group.Seven eyes occurred posterior synechia in combined vitrectomy group and 1 eye in vitrectomy alone group.Conclusion Combined phacoemulsification,intraocular lens implantation with vitrectomy(combined vitrectomy)is safe and effective in treating patients with proliferative diabetic retinopathy.It could avoided second operation for postvitrectomy cataract,and help earlier visual rehabilitation,but it may increase the incidence of fibrin formation and posterior synechia of the iris. Key words: Diabetic retinopathy; Vitrectomy; Phacoemulsification

Comparison of retinal breaks observed during 23 gauge transconjunctival vitrectomy versus conventional 20 gauge surgery for proliferative diabetic retinopathy

BackgroundTo assess the rate and type of retinal break formation in patients undergoing 23 gauge transconjunctival vitrectomy surgery for complications of proliferative diabetic retinopathy compared with 20 gauge vitrectomy surgery.MethodsRetrospective case notes review of two consecutive series of patients who had primary pars plana vitrectomy for complications of proliferative diabetic retinopathy by a single surgeon. The control group had standard 20 gauge vitrectomy surgery whilst the second group had 23 gauge transconjunctival vitrectomy surgery.ResultsEighty-five eyes were included in the 20 gauge group and 85 eyes in the 23 gauge group. The groups were well matched for surgical complexity and indications for surgery, as well as a variety of other preoperative variables. There was a significant reduction in the incidence of peripheral sclerotomy-related retinal breaks and lesions suspicious for breaks (4/85 [5%] 23 gauge versus 14/85 [16%] 20 gauge, P = 0.02) and posterior retinal breaks (3/85 [4%] 23 gauge versus 12/85 [14%] 20 gauge, P = 0.03). Six eyes (7%) in total had definite new retinal breaks of any type detected in the 23 gauge group compared with 16 (18.8%) in the 20 gauge group (P = 0.04). One patient in each group experienced a retinal detachment postoperatively related in both cases to a posterior retinal break associated with recurrent traction.ConclusionIn this series of patients, 23 gauge transconjunctival vitrectomy surgery was associated with a lower rate of retinal break formation than 20 gauge vitrectomy for proliferative diabetic retinopathy.

FIBROUS MEMBRANES IN DIABETIC RETINOPATHY AND BEVACIZUMAB

The purpose of this study was to determine the histopathologic characteristics of bevacizumab-treated human proliferative diabetic retinopathy (PDR) membranes with particular regard to membrane vasculature as a step toward addressing the effects of the drug on PDR membranes. Intravitreous injection of bevacizumab, an antivascular endothelial growth factor monoclonal antibody, has recently been advocated as an adjunct in surgery for PDR. In this context, a clinically observed decrease in PDR epiretinal membrane vascularity (vascular regression) occurs from 24 hours to 48 hours after injection, but the exact mechanisms of drug action are unknown. A consecutive series of seven PDR membrane specimens that had been removed sequentially from seven bevacizumab-treated patients were studied retrospectively. The membrane specimens were examined using light microscopic methods, including immunohistochemistry. Five of the seven membranes were clinically avascular (one contained "ghost" vessels) and did not hemorrhage during excision. Of these 5 specimens, which included 1 removed 7 days after a total of 6 intravitreous injections of 1.25 mg bevacizumab, 4 contained histologically detectable capillaries (1 did not). These blood vessels were lined by endothelial cells as determined by immunohistochemistry for the endothelial markers CD31 and CD34. The two remaining membranes were clinically and histologically still vascularized despite bevacizumab treatment. All the specimens also contained smooth muscle actin-containing fibroblastic cells within the collagenous stroma. The findings do not support the concept that the clinical phenomenon of vascular regression in PDR membranes after bevacizumab injection in the vitreous is resulting from obliteration of the membrane blood vessels. Another mechanism appears to be involved in at least some patients, possibly a vasoconstrictive response. Such a mechanism might explain reversal of the effects of bevacizumab that has been reported after this treatment.

Combining pars plana vitrectomy with cataract surgery for proliferative diabetic retinopathy

目的 探讨经睫状体平坦部闭合式玻璃体切除联合保留前囊晶状体超声乳化及后房型人工晶状体(PCIOL)植入(联合手术)治疗合并白内障的增生性糖尿病视网膜病变(PDR)的临床效果.方法 回顾性分析合并不同程度白内障的PDR 36例(39眼)实施联合手术,观察术后视力改善程度及术中、术后并发症.结果 36例(39眼)成功地进行了联合手术.术后随访2月～3年半,平均13.4月.术后37眼(94.87%)视力不同程度提高,视力≥0.05者26眼(66.67%),≥0.1者17眼(43.59%),≥0.3者7眼(17.95%);视力下降2眼(5.13%).术后视力低下者伴有糖尿病性黄斑水肿、硬性渗出或糖尿病性视神经病变.术中并发症包括晶状体核碎块致视网膜损伤3眼(7.69%)及前囊破裂2眼(5.13%);术后并发症包括玻璃体积血4眼(10.26%),角膜轻度水肿和一过性眼压升高各2眼(5.13%),后发障3眼(7.69%),虹膜红变和眼球萎缩各1眼(2.56%).结论 经睫状体平坦部闭合式玻璃体切除联合保留前囊晶状体超声乳化及PCIOL植入术较安全有效。

The clinical observation of anterior-posterior combined surgery for proliferative diabetic retinopathy

目的 观察后部玻璃体切除联合超声乳化及人工晶状体植入术(简称后三联手术)治疗糖尿病性视网膜病变的疗效.方法 对44眼行后三联手术的糖尿病性视网膜病变进行回顾性分析,并与行单纯玻璃体切除术的50眼糖尿病性视网膜病变进行对比.结果 术后随访2～20月,后三联手术组术后视力0.06以上者43眼(97.73%),0.3以上10眼(22.73%),0.5以上10眼(22.73%);单纯玻璃体切除组术后视力0.06以上者44眼(88.00%),0.3以上8眼(16.00%),0.5以上6眼(12.00%),随访期间22眼(44.00%)二次行白内障手术.结论 后部玻璃体切除联合超声乳化人工晶状体植入术治疗增生期糖尿病性视网膜病变是可行的。

PULSED ELECTRON AVALANCHE KNIFE IN VITREORETINAL SURGERY

To evaluate the advantages, disadvantages, safety, and surgical applicability of the pulsed electron avalanche knife (PEAK-fc), a new electrosurgical knife for "cold" and tractionless cutting, in vitreoretinal surgery. PEAK-fc is equipped with an integrated fiberoptic that makes bimanual procedures in intraocular surgery possible. A prospective consecutive trial of 18 eyes in 18 patients who underwent vitreoretinal surgery for proliferative diabetic retinopathy, proliferative vitreoretinopathy, subretinal macular hemorrhage, or macular pucker was performed. The following specific maneuvers were performed with PEAK-fc: transection of epiretinal membranes, retinotomies, retinal vessel coagulation, and posterior membranectomy. Detached and attached retina could be dissected successfully in eight cases. Intraoperatively, incision edges were sharply demarcated, showing no visible collateral damage. Deeper layers than the neurosensory retina were not affected. With the bimanual approach, epiretinal avascular and vascular membranes could be removed in 10 cases. Hemorrhages occurring during transection of vascularized membranes could be stopped immediately using the coagulation mode of PEAK-fc. Posterior capsule fibrosis was successfully excised in one patient. No complications were observed. PEAK-fc offers precise and tractionless tissue cutting during ocular surgery. Using different waveform parameters, the same device performs cold cutting and/or "hot" coagulation, thus improving the precision, safety, and ergonomics of vitreoretinal surgery.

Intravitreal Dexamethasone Effectively Reduces Postoperative Inflammation After Vitreoretinal Surgery

Corticosteroids remain the mainstay for control of ocular inflammation after vitreous surgery. A controlled, randomized, prospective study was performed to evaluate the effectiveness of a single intravitreal injection of dexamethasone phosphate on postoperative inflammation after simple vitreous surgery in patients with proliferative diabetic retinopathy and macular pucker. Aqueous cell flare intensity was measured preoperatively and on days 1, 10, and 90 in 56 consecutive patients who underwent vitreous surgery for proliferative diabetic retinopathy and macular pucker. Subjects were consecutively randomized to two groups: 400 microg of intravitreal dexamethasone (treatment group) or no dexamethasone (control group) Before surgery, cell and flare intensity was similar in both groups. Flare intensity was significandy lower at 10, 30, and 90 days in the proliferative diabetic retinopathy treatment group (P < .05). Intravitreal dexamethasone significantly alleviates postoperative inflammation after vitreous surgery and is a useful adjunct.

Comparison of Scheimpflug images of posterior capsule opacification and histological findings in rabbits and humans

Purpose: To compare the posterior capsule opacification in Scheimpflug photographic images produced by an electronic anterior eye segment analysis system with the histopathological findings in rabbits and humans. Setting: Department of Ophthalmology, Wakayama Medical College, Japan. Methods: Opacified posterior capsules were photographed using the EAS-1000 system (Nidek) and were then extracted during vitreous surgery for proliferative diabetic retinopathy or proliferative vitreoretinopathy in 2 patients. In rabbits, phacoemulsification and aspiration (PEA) with intraocular lens (IOL) implantation was performed. The IOL was implanted in the bag or in the sulcus. After intervals of healing, the posterior capsule was photographed with the EAS-1000 and the animals were then killed. In both clinical and experimental specimens, the posterior capsule was processed for light microscopic histology and immunohistochemistry. Results: Opacified human capsules were well imaged by the EAS-1000. Histology showed that lens epithelial cells proliferated with and without an accumulation of extracellular matrix. Details such as rolling of the capsulotomy edge were seen well. Regenerated lens fibers of Soemmering’s ring were seen as a mass within the capsule. In the rabbit model, Scheimpflug images accurately represented the capsules as they appeared histologically. Conclusion: The EAS-1000 system provided faithful, relatively high-resolution images that corresponded to the histologic findings in the posterior capsules after PEA-IOL surgery in humans and rabbits.

Progress in vitreoretinal surgery for proliferative diabetic retinopathy

(2001). Progress in vitreoretinal surgery for proliferative diabetic retinopathy. Seminars in Ophthalmology: Vol. 16, No. 1, pp. 31-40.

Reliability of Standardized Echography before Vitreoretinal Surgery for Proliferative Diabetic Retinopathy

Standardized A- and B-scan echography was performed in 45 patients (68 eyes) affected by proliferative diabetic retinopathy, before vitreoretinal surgery, to evaluate the percentage of agreement between the ultrasonographic data and the surgical findings. The agreement was quite good for tractional retinal detachment (93%) and for posterior vitreous detachment (91%). The main cause of failure was the presence of vitreoschisis, while preretinal and vitreal membranes can easily be detected.

Transient Shallow Anterior Chamber Induced by Supraciliary Fluid After Vitreous Surgery

To report the mechanism of transient shallow anterior chamber after vitreous surgery for proliferative diabetic retinopathy. Using ultrasound biomicroscopy, we examined a patient with transient shallow anterior chamber after vitreous surgery for proliferative diabetic retinopathy. On the day after surgery, slit-lamp examination disclosed a shallow anterior chamber that persisted for 1 week and deepened thereafter. Ultrasound biomicroscopy 5 days postoperatively disclosed a narrow angle in the peripheral anterior chamber and supraciliary fluid. At 14 days postoperatively, suprachoroidal fluid could not be detected, and the angle was wide. The shallow anterior chamber in this patient was caused by supraciliary fluid after vitreous surgery.

Long-term results of vitreous surgery for proliferative diabetic retinopathy.

In order to study long-term anatomical and functional results the authors evaluated the data from 260 patients who underwent pars plana vitrectomy for proliferative diabetic retinopathy. Indications for surgery were: vitreous hemorrhage, 68 eyes (26.2%); vitreous hemorrhage & tractional retinal detachment, 84 eyes (32.3%); tractional retinal detachment, 82 eyes (31.5%); and combined tractional-rhegmatogenous retinal detachment, 26 eyes (10%). In 118 eyes vitreoretinal surgery was combined with silicone-oil tamponade. The retina was completely attached posterior to a scleral buckle in 251 eyes (96%) at the time of the last examination. After a follow-up period of at least 12 months in a group of patients with vitreous hemorrhage, visual acuity improved in 88% of the eyes. Visual acuity was better than 0.5 in 31% of eyes. In group of eyes with nonresorbing vitreous hemorrhage & tractional retinal detachment visual acuity improved in 52% of eyes. Visual acuity improved in 76% of eyes with tractional retinal detachment and in 81% of eyes with combined tractional & rhegmatogenous retinal detachment. When comparing the latest postoperative visual acuity to visual acuity after three months postoperatively, visual acuity was unchanged in 88%, in 10% it became worse and in 3 cases (1%) became better. In the postoperative period, recurrent vitreous hemorrhage occurred in 33 (13%) eyes, reproliferation in 12 eyes. Cataract developed in 45 of 168 phakic eyes. If postoperative visual acuity before cataract formation was good, extracapsular cataract extraction with posterior chamber intraocular lens implantation was performed. Otherwise simple intra or extracapsular cataract extraction was performed. In 19 cases cataract operation was performed together with silicone oil extraction. Neovascular glaucoma developed postoperatively in 15 eyes (6%). Retinal detachment occurred postoperatively in 21 eyes (8%). In 15 eyes the retina was successfully reattached after additional operations.

Characterization of Glial Involvement in Proliferative Diabetic Retinopathy

We studied the relationship of glial cells and other supporting tissues associated with newly formed blood vessels in proliferative diabetic retinopathy. Seventeen postmortem, freshly enucleated eyes from diabetic patients and 34 epiretinal and preretinal membranes removed during vitreous surgery for proliferative diabetic retinopathy were analyzed using the peroxidase-antiperoxidase method for light microscopy and protein A/gold labeling of ultrathin cryosections for transmission electron microscopy in addition to routine transmission and scanning electron microscopy. We found that glial cells are commonly and characteristically found in elevated diabetic proliferations and present at the vitreous surface. The newly formed blood vessels, however, were not seen at the edge of elevated epiretinal and preretinal membranes in early and intermediate stages. These results suggest that glial cells may extend beyond the vascularized areas of the proliferative tissue. It is possible that glial cells and their extracellular matrix contribute to the framework leading to the development of new blood vessels.