Management of Specific Diseases Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
Surgical Management of Retinal Diseases: Proliferative Diabetic Retinopathy and Traction Retinal Detachment Yousef J. Cruz-Iñigo · Luis A. Acabá · Maria H. Berrocal Department of Ophthalmology, University of Puerto Rico, San Juan, Puerto Rico
Current indications for pars plana vitrectomy in patients with proliferative diabetic retinopathy (PDR) include vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), diabetic macular edema associated with posterior hyaloidal traction, and anterior segment neovascularization with media opacities. This chapter will review the indications, surgical objectives, adjunctive pharmacotherapy, microincision surgical techniques, and outcomes of diabetic vitrectomy for PDR, TRD, and CTRRD. With the availability of new microincision vitrectomy technology, wide-angle microscope viewing systems, and pharmacologic agents, vitrectomy can improve visual acuity and achieve long-term anatomic stability in eyes with severe complications from PDR. © 2014 S. Karger AG, Basel
Pars plana vitrectomy was initially performed on diabetic patients with nonclearing vitreous hemorrhage. The results obtained were favorable and triggered a strong interest for studying disease pathogenesis as well as improving surgical techniques and technologies in order to maximize
outcomes and minimize complications. The Diabetic Retinopathy Treatment Study was pivotal in showing the impact of early diabetic vitrectomy [1–4]. In the past 12 years, 23-, 25-, and 27-gauge transconjunctival sutureless vitrectomy systems have been introduced [5–7] and antiangiogenic molecules have become available as adjuvants in diabetic vitrectomy [8–12]. These technologies have streamlined vitrectomy procedures, expanded the pathologies that can be addressed with vitrectomy, and improved outcomes. Current objectives of vitrectomy in proliferative diabetic retinopathy (PDR) include removal of vitreous opacities, excision of the posterior hyaloid, release of retinal traction, retinal reattachment, treatment of retinal ischemia, and prevention of fibrovascular proliferation. The most frequent indications for vitrectomy in patients with PDR include: nonclearing vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), macular traction syndromes, and neovascular glaucoma. Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/15/2015 4:21:37 PM
Abstract
Vitreous Hemorrhage
Fig. 1. Optical coherence tomography of an eye with longstanding TRD with severe cystoid degeneration, localized detachment, and membranes on the retinal surface.
Tractional Retinal Detachment and Traction and Rhegmatogenous Retinal Detachment
TRD has been the most frequent indication for vitrectomy in diabetic patients, accounting for 40% of diabetic vitrectomies [15]. TRD results from progressive fibrovascular proliferation and contraction, which pulls the neurosensory retina away from the retinal pigment epithelium. This detachment can involve the macula causing severe visual acuity loss. With progressive fibrovascular contraction in eyes with a TRD and thin ischemic retina, retinal breaks can occur resulting in a TRD with a rhegmatogenous component (CTRRD). These patients present with abrupt and rapidly progressive visual loss. Fundoscopic findings include a taut, concave, immobile retina without breaks with associated fibrovascular areas of proliferation. Optical coherence tomography is useful in determining the degree of foveal involvement in tractional detachments as well as the concomitant presence of epiretinal membranes (fig. 1). It
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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Vitreous hemorrhage was the most common indication for vitrectomy in patients with PDR. Although with the introduction of panretinal photocoagulation (PRP) the prevalence of severe vitreous hemorrhage has decreased over time, it still remains a common indication worldwide. PRP causes regression of neovascular tissue, thus helping prevent future hemorrhages and retinal detachments. In the early 1980s it was common to wait for clearing of vitreous hemorrhage since instrumentation was limited, intraoperative photocoagulation was not available, and complications including rebleeding were common [13]. With new technological advances, fewer complications are seen with diabetic vitrectomy. Currently, early vitrectomy is indicated for dense vitreous hemorrhages, while observation is reserved for mild cases that could clear spontaneously. When vitreous hemorrhage obscures a fundus view, B-scan ultrasonography is required to rule out concomitant retinal detachment. Surgical objectives include removing vitreous opacities caused by bleeding, relieving vitreoretinal traction by removing the posterior hyaloid and epiretinal membranes, and applying endophotocoagulation to achieve regression of proliferative tissue [14]. Surgical management of this condition has been simplified with microincision vitrectomy surgery and wide-angle viewing systems. New vitrectors in 23, 25 and 27 gauge with optimized fluidics and cutting rates of up to 7,500 cuts/min allow for very efficient vitreous removal with minimized traction on the retina. Optimized intraocular pressure control minimizes bleeding during surgery and reduces the need for endocautery. The introduction of curved laser probes allow for complete photocoagulation up to the ora serrata even in phakic eyes. These techniques result in long-term stabilization of vitrectomized eyes.
b
Fig. 2. a Pre-bevacizumab photo of an eye of a 34-yearold patient with total CTRRD. Visual acuity: hand motion. b Four days after bevacizumab injection. c 6 months after vitrectomy with 23-gauge instrumentation. Visual acuity 20/100.
c
is not uncommon for eyes with a vitreous hemorrhage to have areas of TRD discovered during surgery. The objectives of vitrectomy are to relieve retinal traction, detach and remove the posterior hyaloid, reattach the retina, and treat areas of retinal ischemia to prevent vascular endothelial growth factor (VEGF) production and consequent neovascularization. Traditionally, surgery is done for TRDs that threaten or involve the fovea while photocoagulation is indicated for small extrafoveal TRDs, as these can remain stable for years without the need for vitrectomy.
Surgical complexity is very variable, and depends on how strongly the fibrovascular tissue adheres to the retina, degree of vascularity, extension of membranes, and the thinness and degree of ischemia of the retina. Preoperative administration of anti-VEGF for eyes with severe vascular tissue reduces the risk of intraoperative bleeding and facilitates the surgery. Low doses (12.5 mg) of bevacizumab (Avastin) should be injected no more than 5 days prior to surgery to avoid increased fibrovascular contraction and subsequent worsening of the retinal detachment [12, 16, 17] (fig. 2a–c). Despite the fact that microincision
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Cruz-Iñigo · Acabá · Berrocal Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/15/2015 4:21:37 PM
a
Combined Tractional and Rhegmatogenous Retinal Detachment
Strong vitreoretinal traction produced by fibrovascular tissue can threaten retinal surface integrity. If a retinal break occurs, then liquefied vitreous can penetrate into the subretinal space and separate the overlying retina from the retinal pigment epi-
Fig. 3. Membrane dissection with 27-gauge vitrectomy probe in a TRD.
Fig. 4. Blunt dissection of fibrovascular tissue with a 27-gauge vitrectomy probe on CTRRD.
thelium causing CTRRD. Fundoscopic findings in these combined detachments show a convex retina with bullous or mobile retina in some areas (fig. 4). Retinal breaks are usually localized posterior to the equator and adjacent to areas of fibrovascular proliferation in a thin retina. Symptoms include sudden, progressive, and profound visual loss. In these cases, early vitrectomy is indicated to prevent permanent visual loss [18, 19]. These are the most complex diabetic surgeries as they require difficult techniques for removing fibrovascular tissue from the detached retina, closing retinal breaks, and reattaching the retina. Particularly useful instruments are the 25- and
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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probes serve as multifunction instruments, precluding the need for many instruments during the procedure, it is still important to have all the ancillary instrumentation that may be required including hyaluronic acid, scissors, chandelier illuminators, forceps, and diathermy. The surgical technique involves performing a core vitrectomy, removing all vitreous opacities, and detaching the posterior hyaloid. Areas of fibrovascular proliferation are segmented or dissected with the vitrectomy probe or with scissors or bimanual techniques (fig. 3). The aim is to remove all of the fibrovascular tissue that causes traction. In cases with very adherent tissue, chandeliers for bimanual techniques or hyaluronic acid injection to separate fibrovascular tissue from the retina can be useful. If removal of the fibrovascular tissue is possible without iatrogenic breaks, photocoagulation is then applied. However, air-fluid exchange at the end of the procedure with prone positioning for a few days is indicated when foveal elevation or folds are prominent to reduce postoperative metamorphopsia. Nasal areas of traction that do not threaten to involve the posterior pole do not need to be removed as long as there is no rhegmatogenous component or iatrogenic breaks. The most serious complication of vitrectomy for TRD is the creation of iatrogenic retinal breaks. When these occur the surgeon should remove all the fibrovascular tissue, drain the subretinal liquid, perform air-fluid exchange, photocoagulate the breaks, and use long-acting intraocular gas or silicone oil tamponade.
to the Diabetic Retinopathy Vitrectomy Study Research Group, the most adequate candidates for early vitrectomy are patients with severe fibrovascular proliferation, and those with extensive prior photocoagulation or those with media opacities that prevent photocoagulation [2]. Others have confirmed that despite early and extensive retinal photocoagulation, fibrovascular and neovascular proliferations progress rapidly [21]. Thus, early vitrectomy offers the best results as neovascularization of the optic nerve and posterior pole rarely occurs following surgical excision of the posterior cortical vitreous.
Complications
Difficult Diabetic Vitrectomies
Complications of vitrectomy for PDR, TRD, and CTRRD include rebleeding or nonclearing residual vitreous hemorrhage. This is more common in cases that have very vascular membranes and in patients with uncontrolled hypertension who are anticoagulated or have hypotony on the first day postoperatively. This can resolve with observation, can be managed with an in-office air-fluid exchange, or with a repeat vitrectomy in the operating room. Other complications include rhegmatogenous retinal detachment from iatrogenic breaks that were either not detected during the surgery or that reopened. In these cases a reoperation with a longacting tamponade either with gas or silicone oil is required. Rubeosis and neovascular glaucoma are challenging complications. They are seen in very ischemic eyes or eyes that have peripheral detachments, and are managed with anti-VEGF injections, photocoagulation, repair of peripheral detachment if present, and sometimes a silicone oil tamponade.
Diabetic eyes are more susceptible to cataract formation and corneal edema causing poor visibility during long surgical procedures. Prior to microincision victrectomy surgery, either irrigating glucose solutions or corneal epithelium debridement were used to improve visibility [22]. Microincision victrectomy surgery has shortened surgical time and, consequently, these complications are now seen less frequently. Microincision surgery has reduced the frequency of iatrogenic breaks in several ways: microcannulas protect the vitreous base when entering and removing instruments such as scissors and forceps, the vitrectomy probe can be used as a multipurpose instrument and cutting rates of up to 7,500 cuts/min allow vitreous removal with minimal traction, and intraocular pressure control helps to prevent intraocular turbulence which can cause vitreous and retinal avulsions during surgery. The diabetic eye, due to its ischemic state, is more susceptible to neovascularization at the sclerotomy entry sites and vitreous base [23, 24]. Most commonly this is evident for eyes requiring reoperation and with large sclerotomies. Smaller sclerotomies using 25- and 23-gauge systems help reduce inflammation and neovascularization responsible for postoperative bleeding.
Severe Fibrovascular Proliferation
Understanding the different types of vitreoretinal adhesions in PDR helps the surgeon to establish the best surgery for each patient. According
200
Cruz-Iñigo · Acabá · Berrocal Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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27-gauge vitreous cutters introduced between the membranes to dissect and shave the fibrovascular tissue. In addition, cutting rates of up to 7,500 cuts/ min exert minimal traction over the detached retina and chandelier illuminators, particularly 25- or 29-gauge, and facilitate bimanual fibrovascular tissue dissection (fig. 5a, b). In addition, hyaluronic acid can be used to separate the attached fibrous membranes from the mobile retina. Although the prognosis is reserved, good preoperative prognostic factors include recent onset, visual acuity of 5/200 or better, and absence of rubeosis and of retinal detachment involving the macula [15, 20].
a
b
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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Fig. 5. a Preoperative traction and rhegmatogenous retinal detachment with fibrovascular proliferation and subretinal membranes managed with 25-gauge vitrectomy. b Postoperative view with an attached retina and 30% residual gas bubble.
Intraoperative bleeding in diabetic eyes is a common problem. If severe, completing the procedure can become very challenging. Bleeding commonly occurs in neovascular areas, particularly when exchanging instruments due to sudden changes in intraocular pressure. However, the new vitrectomy systems, combined with smaller sclerotomies, allow for controlling intraocular pressure during surgery and reduced bleeding. In addition, preoperative treatment with an antiangiogenic agent facilitates dissecting fibrovascular membranes in patients with tractional and/or rhegmatogenous retinal detachments.
Conclusion
Microincision vitrectomy surgery is ideal for late complications of PDR. Small-gauge instrumentation allow for rapid, safe, and elegant removal of fibrovascular tissue. High-speed cutting rates minimize traction. Preoperative application of antiangiogenic therapy, for selected cases, and reduced surgical time have decreased surgical complications and increased positive outcomes. As a result, surgical intervention for complicated diabetic retinopathy can be performed earlier than suggested by the DVS, allowing for better visual and anatomical results.
References
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6 Fujii GY, De Juan E Jr, Humayun MS, et al: Initial experience using the transconjunctival sutureless vitrectomy system for vitreoretinal surgery. Ophthalmology 2002;109:1814–1820. 7 Eckardt C: Transconjunctival sutureless 23-gauge vitrectomy. Retina 2005;25: 208–211. 8 da R Lucena D, Ribeiro JA, Costa RA, et al: Intraoperative bleeding during vitrectomy for diabetic tractional retinal detachment with versus without preoperative intravitreal bevacizumab (IBeTra study). Br J Ophthalmol 2009;93:688– 691. 9 Rizzo S, Genovesi-Ebert F, Di Bartolo E, et al: Injection of intravitreal bevacizumab (Avastin) as a preoperative adjunct before vitrectomy surgery in the treatment of severe proliferative diabetic retinopathy (PDR). Graefes Arch Clin Exp Ophthalmol 2008;246:837–842. 10 Yeoh J, Williams C, Allen P, et al: Avastin as an adjunct to vitrectomy in the management of severe proliferative diabetic retinopathy: a prospective case series. Clin Experiment Ophthalmol 2008;36:449–454. 11 Ishikawa K, Honda S, Tsukahara Y, Negi A: Preferable use of intravitreal bevacizumab as a pretreatment of vitrectomy for severe proliferative diabetic retinopathy. Eye (Lond) 2009;23:108–111.
12 Oshima Y, Shima C, Wakabayashi T, et al: Microincision vitrectomy surgery and intravitreal bevacizumab as a surgical adjunct to treat diabetic traction retinal detachment. Ophthalmology 2009; 116:927–938. 13 Michels RG, Rice TA, Rice EF: Vitrectomy for diabetic vitreous hemorrhage. Am J Ophthalmol 1983; 95: 12– 21. 14 Chaudhry NA, Lim ES, Saito Y, et al: Early vitrectomy and endolaser photocoagulation in patients with type I diabetes with severe vitreous hemorrhage. Ophthalmology 1995;102:1164–1169. 15 Rice TA, Michels RG, Rice EF: Vitrectomy for diabetic traction retinal detachment involving the macula. Am J Ophthalmol 1983;95:22–33. 16 Arevalo JF, Maia M, Flynn HW Jr, et al: Tractional retinal detachment following intravitreal bevacizumab (Avastin) in patients with severe proliferative diabetic retinopathy. Br J Ophthalmol 2008;92: 213–216. 17 Arevalo JF, Sanchez JG, Saldarriaga L, et al: Retinal detachment after bevacizumab. Ophthalmology 2011;118:2304.e3– e7. 18 Thompson JT, de Bustros S, Michels RG, Rice TA: Results and prognostic factors in vitrectomy for diabetic tractionrhegmatogenous retinal detachment. Arch Ophthalmol 1987;105:503–507.
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1 Early vitrectomy for severe proliferative diabetic retinopathy in eyes with useful vision. Clinical application of results of a randomized trial – Diabetic Retinopathy Vitrectomy Study Report 4. The Diabetic Retinopathy Vitrectomy Study Research Group. Ophthalmology 1988;95: 1321–1334. 2 Early vitrectomy for severe vitreous hemorrhage in diabetic retinopathy. Two-year results of a randomized trial. Diabetic Retinopathy Vitrectomy Study Report 2. The Diabetic Retinopathy Vitrectomy Study Research Group. Arch Ophthalmol 1985;103:1644–1652. 3 Early vitrectomy for severe vitreous hemorrhage in diabetic retinopathy. Four-year results of a randomized trial: Diabetic Retinopathy Vitrectomy Study Report 5. Arch Ophthalmol 1990;108: 958–964. 4 Early vitrectomy for severe proliferative diabetic retinopathy in eyes with useful vision. Results of a randomized trial – Diabetic Retinopathy Vitrectomy Study Report 3. The Diabetic Retinopathy Vitrectomy Study Research Group. Ophthalmology 1988;95:1307–1320. 5 Fujii GY, De Juan E Jr, Humayun MS, Pieramici DJ, Chang TS, Awh C, et al: A new 25-gauge instrument system for transconjunctival sutureless vitrectomy surgery. Ophthalmology 2002;109: 1807–1812.
19 Yang CM, Su PY, Yeh PT, Chen MS: Combined rhegmatogenous and traction retinal detachment in proliferative diabetic retinopathy: clinical manifestations and surgical outcome. Can J Ophthalmol 2008;43:192–198. 20 Rice TA, Michels RG, Rice EF: Vitrectomy for diabetic rhegmatogenous retinal detachment. Am J Ophthalmol 1983; 95:34–44.
21 Davis MD: Vitreous contraction in PDR. Arch Ophthalmol 1965;74:741–751. 22 Smiddy WE, Feuer W: Incidence of cataract extraction after diabetic vitrectomy. Retina 2004;24:574–581.
23 Rice TA, Michels RG, Maguire MG, Rice EF: The effect of lensectomy on the incidence of iris neovascularization and neovascular glaucoma after vitrectomy for diabetic retinopathy. Am J Ophthalmol 1983;95:1–11. 24 Jaffe GJ, Lewis H, Han DP, Williams GA, Abrams GW: Treatment of postvitrectomy fibrin pupillary block with tissue plasminogen activator. Am J Ophthalmol 1989;108:170–175.
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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Yousef J. Cruz-Iñigo Department of Ophthalmology University of Puerto Rico Rio Piedras Medical Center 00909 San Juan (Puerto Rico) E-Mail [email protected]
Surgical Management of Retinal Diseases: Proliferative Diabetic Retinopathy and Traction Retinal Detachment Yousef J. Cruz-Iñigo · Luis A. Acabá · Maria H. Berrocal Department of Ophthalmology, University of Puerto Rico, San Juan, Puerto Rico
Current indications for pars plana vitrectomy in patients with proliferative diabetic retinopathy (PDR) include vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), diabetic macular edema associated with posterior hyaloidal traction, and anterior segment neovascularization with media opacities. This chapter will review the indications, surgical objectives, adjunctive pharmacotherapy, microincision surgical techniques, and outcomes of diabetic vitrectomy for PDR, TRD, and CTRRD. With the availability of new microincision vitrectomy technology, wide-angle microscope viewing systems, and pharmacologic agents, vitrectomy can improve visual acuity and achieve long-term anatomic stability in eyes with severe complications from PDR. © 2014 S. Karger AG, Basel
Pars plana vitrectomy was initially performed on diabetic patients with nonclearing vitreous hemorrhage. The results obtained were favorable and triggered a strong interest for studying disease pathogenesis as well as improving surgical techniques and technologies in order to maximize
outcomes and minimize complications. The Diabetic Retinopathy Treatment Study was pivotal in showing the impact of early diabetic vitrectomy [1–4]. In the past 12 years, 23-, 25-, and 27-gauge transconjunctival sutureless vitrectomy systems have been introduced [5–7] and antiangiogenic molecules have become available as adjuvants in diabetic vitrectomy [8–12]. These technologies have streamlined vitrectomy procedures, expanded the pathologies that can be addressed with vitrectomy, and improved outcomes. Current objectives of vitrectomy in proliferative diabetic retinopathy (PDR) include removal of vitreous opacities, excision of the posterior hyaloid, release of retinal traction, retinal reattachment, treatment of retinal ischemia, and prevention of fibrovascular proliferation. The most frequent indications for vitrectomy in patients with PDR include: nonclearing vitreous hemorrhage, tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), macular traction syndromes, and neovascular glaucoma. Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/15/2015 4:21:37 PM
Abstract
Vitreous Hemorrhage
Fig. 1. Optical coherence tomography of an eye with longstanding TRD with severe cystoid degeneration, localized detachment, and membranes on the retinal surface.
Tractional Retinal Detachment and Traction and Rhegmatogenous Retinal Detachment
TRD has been the most frequent indication for vitrectomy in diabetic patients, accounting for 40% of diabetic vitrectomies [15]. TRD results from progressive fibrovascular proliferation and contraction, which pulls the neurosensory retina away from the retinal pigment epithelium. This detachment can involve the macula causing severe visual acuity loss. With progressive fibrovascular contraction in eyes with a TRD and thin ischemic retina, retinal breaks can occur resulting in a TRD with a rhegmatogenous component (CTRRD). These patients present with abrupt and rapidly progressive visual loss. Fundoscopic findings include a taut, concave, immobile retina without breaks with associated fibrovascular areas of proliferation. Optical coherence tomography is useful in determining the degree of foveal involvement in tractional detachments as well as the concomitant presence of epiretinal membranes (fig. 1). It
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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Vitreous hemorrhage was the most common indication for vitrectomy in patients with PDR. Although with the introduction of panretinal photocoagulation (PRP) the prevalence of severe vitreous hemorrhage has decreased over time, it still remains a common indication worldwide. PRP causes regression of neovascular tissue, thus helping prevent future hemorrhages and retinal detachments. In the early 1980s it was common to wait for clearing of vitreous hemorrhage since instrumentation was limited, intraoperative photocoagulation was not available, and complications including rebleeding were common [13]. With new technological advances, fewer complications are seen with diabetic vitrectomy. Currently, early vitrectomy is indicated for dense vitreous hemorrhages, while observation is reserved for mild cases that could clear spontaneously. When vitreous hemorrhage obscures a fundus view, B-scan ultrasonography is required to rule out concomitant retinal detachment. Surgical objectives include removing vitreous opacities caused by bleeding, relieving vitreoretinal traction by removing the posterior hyaloid and epiretinal membranes, and applying endophotocoagulation to achieve regression of proliferative tissue [14]. Surgical management of this condition has been simplified with microincision vitrectomy surgery and wide-angle viewing systems. New vitrectors in 23, 25 and 27 gauge with optimized fluidics and cutting rates of up to 7,500 cuts/min allow for very efficient vitreous removal with minimized traction on the retina. Optimized intraocular pressure control minimizes bleeding during surgery and reduces the need for endocautery. The introduction of curved laser probes allow for complete photocoagulation up to the ora serrata even in phakic eyes. These techniques result in long-term stabilization of vitrectomized eyes.
b
Fig. 2. a Pre-bevacizumab photo of an eye of a 34-yearold patient with total CTRRD. Visual acuity: hand motion. b Four days after bevacizumab injection. c 6 months after vitrectomy with 23-gauge instrumentation. Visual acuity 20/100.
c
is not uncommon for eyes with a vitreous hemorrhage to have areas of TRD discovered during surgery. The objectives of vitrectomy are to relieve retinal traction, detach and remove the posterior hyaloid, reattach the retina, and treat areas of retinal ischemia to prevent vascular endothelial growth factor (VEGF) production and consequent neovascularization. Traditionally, surgery is done for TRDs that threaten or involve the fovea while photocoagulation is indicated for small extrafoveal TRDs, as these can remain stable for years without the need for vitrectomy.
Surgical complexity is very variable, and depends on how strongly the fibrovascular tissue adheres to the retina, degree of vascularity, extension of membranes, and the thinness and degree of ischemia of the retina. Preoperative administration of anti-VEGF for eyes with severe vascular tissue reduces the risk of intraoperative bleeding and facilitates the surgery. Low doses (12.5 mg) of bevacizumab (Avastin) should be injected no more than 5 days prior to surgery to avoid increased fibrovascular contraction and subsequent worsening of the retinal detachment [12, 16, 17] (fig. 2a–c). Despite the fact that microincision
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Cruz-Iñigo · Acabá · Berrocal Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
Downloaded by: Nanyang Technological Univ. 198.143.39.65 - 6/15/2015 4:21:37 PM
a
Combined Tractional and Rhegmatogenous Retinal Detachment
Strong vitreoretinal traction produced by fibrovascular tissue can threaten retinal surface integrity. If a retinal break occurs, then liquefied vitreous can penetrate into the subretinal space and separate the overlying retina from the retinal pigment epi-
Fig. 3. Membrane dissection with 27-gauge vitrectomy probe in a TRD.
Fig. 4. Blunt dissection of fibrovascular tissue with a 27-gauge vitrectomy probe on CTRRD.
thelium causing CTRRD. Fundoscopic findings in these combined detachments show a convex retina with bullous or mobile retina in some areas (fig. 4). Retinal breaks are usually localized posterior to the equator and adjacent to areas of fibrovascular proliferation in a thin retina. Symptoms include sudden, progressive, and profound visual loss. In these cases, early vitrectomy is indicated to prevent permanent visual loss [18, 19]. These are the most complex diabetic surgeries as they require difficult techniques for removing fibrovascular tissue from the detached retina, closing retinal breaks, and reattaching the retina. Particularly useful instruments are the 25- and
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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probes serve as multifunction instruments, precluding the need for many instruments during the procedure, it is still important to have all the ancillary instrumentation that may be required including hyaluronic acid, scissors, chandelier illuminators, forceps, and diathermy. The surgical technique involves performing a core vitrectomy, removing all vitreous opacities, and detaching the posterior hyaloid. Areas of fibrovascular proliferation are segmented or dissected with the vitrectomy probe or with scissors or bimanual techniques (fig. 3). The aim is to remove all of the fibrovascular tissue that causes traction. In cases with very adherent tissue, chandeliers for bimanual techniques or hyaluronic acid injection to separate fibrovascular tissue from the retina can be useful. If removal of the fibrovascular tissue is possible without iatrogenic breaks, photocoagulation is then applied. However, air-fluid exchange at the end of the procedure with prone positioning for a few days is indicated when foveal elevation or folds are prominent to reduce postoperative metamorphopsia. Nasal areas of traction that do not threaten to involve the posterior pole do not need to be removed as long as there is no rhegmatogenous component or iatrogenic breaks. The most serious complication of vitrectomy for TRD is the creation of iatrogenic retinal breaks. When these occur the surgeon should remove all the fibrovascular tissue, drain the subretinal liquid, perform air-fluid exchange, photocoagulate the breaks, and use long-acting intraocular gas or silicone oil tamponade.
to the Diabetic Retinopathy Vitrectomy Study Research Group, the most adequate candidates for early vitrectomy are patients with severe fibrovascular proliferation, and those with extensive prior photocoagulation or those with media opacities that prevent photocoagulation [2]. Others have confirmed that despite early and extensive retinal photocoagulation, fibrovascular and neovascular proliferations progress rapidly [21]. Thus, early vitrectomy offers the best results as neovascularization of the optic nerve and posterior pole rarely occurs following surgical excision of the posterior cortical vitreous.
Complications
Difficult Diabetic Vitrectomies
Complications of vitrectomy for PDR, TRD, and CTRRD include rebleeding or nonclearing residual vitreous hemorrhage. This is more common in cases that have very vascular membranes and in patients with uncontrolled hypertension who are anticoagulated or have hypotony on the first day postoperatively. This can resolve with observation, can be managed with an in-office air-fluid exchange, or with a repeat vitrectomy in the operating room. Other complications include rhegmatogenous retinal detachment from iatrogenic breaks that were either not detected during the surgery or that reopened. In these cases a reoperation with a longacting tamponade either with gas or silicone oil is required. Rubeosis and neovascular glaucoma are challenging complications. They are seen in very ischemic eyes or eyes that have peripheral detachments, and are managed with anti-VEGF injections, photocoagulation, repair of peripheral detachment if present, and sometimes a silicone oil tamponade.
Diabetic eyes are more susceptible to cataract formation and corneal edema causing poor visibility during long surgical procedures. Prior to microincision victrectomy surgery, either irrigating glucose solutions or corneal epithelium debridement were used to improve visibility [22]. Microincision victrectomy surgery has shortened surgical time and, consequently, these complications are now seen less frequently. Microincision surgery has reduced the frequency of iatrogenic breaks in several ways: microcannulas protect the vitreous base when entering and removing instruments such as scissors and forceps, the vitrectomy probe can be used as a multipurpose instrument and cutting rates of up to 7,500 cuts/min allow vitreous removal with minimal traction, and intraocular pressure control helps to prevent intraocular turbulence which can cause vitreous and retinal avulsions during surgery. The diabetic eye, due to its ischemic state, is more susceptible to neovascularization at the sclerotomy entry sites and vitreous base [23, 24]. Most commonly this is evident for eyes requiring reoperation and with large sclerotomies. Smaller sclerotomies using 25- and 23-gauge systems help reduce inflammation and neovascularization responsible for postoperative bleeding.
Severe Fibrovascular Proliferation
Understanding the different types of vitreoretinal adhesions in PDR helps the surgeon to establish the best surgery for each patient. According
200
Cruz-Iñigo · Acabá · Berrocal Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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27-gauge vitreous cutters introduced between the membranes to dissect and shave the fibrovascular tissue. In addition, cutting rates of up to 7,500 cuts/ min exert minimal traction over the detached retina and chandelier illuminators, particularly 25- or 29-gauge, and facilitate bimanual fibrovascular tissue dissection (fig. 5a, b). In addition, hyaluronic acid can be used to separate the attached fibrous membranes from the mobile retina. Although the prognosis is reserved, good preoperative prognostic factors include recent onset, visual acuity of 5/200 or better, and absence of rubeosis and of retinal detachment involving the macula [15, 20].
a
b
PDR/TRD Oh H, Oshima Y (eds): Microincision Vitrectomy Surgery. Emerging Techniques and Technology. Dev Ophthalmol. Basel, Karger, 2014, vol 54, pp 196–203 (DOI: 10.1159/000360467)
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Fig. 5. a Preoperative traction and rhegmatogenous retinal detachment with fibrovascular proliferation and subretinal membranes managed with 25-gauge vitrectomy. b Postoperative view with an attached retina and 30% residual gas bubble.
Intraoperative bleeding in diabetic eyes is a common problem. If severe, completing the procedure can become very challenging. Bleeding commonly occurs in neovascular areas, particularly when exchanging instruments due to sudden changes in intraocular pressure. However, the new vitrectomy systems, combined with smaller sclerotomies, allow for controlling intraocular pressure during surgery and reduced bleeding. In addition, preoperative treatment with an antiangiogenic agent facilitates dissecting fibrovascular membranes in patients with tractional and/or rhegmatogenous retinal detachments.
Conclusion
Microincision vitrectomy surgery is ideal for late complications of PDR. Small-gauge instrumentation allow for rapid, safe, and elegant removal of fibrovascular tissue. High-speed cutting rates minimize traction. Preoperative application of antiangiogenic therapy, for selected cases, and reduced surgical time have decreased surgical complications and increased positive outcomes. As a result, surgical intervention for complicated diabetic retinopathy can be performed earlier than suggested by the DVS, allowing for better visual and anatomical results.
References
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Yousef J. Cruz-Iñigo Department of Ophthalmology University of Puerto Rico Rio Piedras Medical Center 00909 San Juan (Puerto Rico) E-Mail [email protected]
