Ординатура / Офтальмология / Английские материалы / Retinal and Vitreoretinal Diseases and Surgery_Boyd, Cortez, Sabates_2010

Surgical Procedure in

Luxated Lens Material

This technique is preferred when there is a significant posterior capsular disruption, trauma, rupture or dislocation and vitreous prolapsed into the anterior chamber. The surgical goal is to remove the entire lens, prolapsed vitreous and, if required, to manage any posterior segment traumatic abnormality (vitreous hemorrhage, intraocular foreign body (IOFB), retinal detachment, etc., (Figure 4).

Pars plana lensectomy is of undoubted value in the older patient with a hard lens, which requires ultrasonic fragmentation before aspiration. Should posterior displacement of lens matter occur, it allows easy acces to the vitreous cavity. The goal is to remove the entire lens, prolapsed vitreous, and in some cases to insert an intraocular lens. The procedure is as follow: Creation of three conjuntival disections: inferotemporal, superotemporal and superonasal. Three sclerotomies at the same sites, 3.0 mm posterior to the limbus, with a MVR blade (in children under three years of age), the sclerotomies are created more anteriorly because the pars plana is not fully developed. A 4- or 6-mm infusion cannula is sutured in place into the inferotemporal sclerotomy. The infusion is not turned on until the cannula port is visualized in the vitreous cavity. The MVR blade is introduced through one of the sclerotomies and passed through the equator of the nucleus to judge central hardness. In children, or young adults, the lens can be removed with the cutting/aspiration probe.

In older individuals with harder lenses, the lens nucleus require ultrasonic fragmentation before irrigation and aspiration of the cortex and posterior capsule. Depression with a cot- ton-tipped applicator can aid in removal of peripheral lens material. Vitrectomy should be performed for removal of anterior prolapsed vitreous, significant vitreous opacity (usually blood), and retrieval of dropped lens fragments (Figure 5).

Posterior lens fragments are crushed between an endoillumination probe and the vitreous cutter, after the surrounding vitreous has been removed. Fragmentation is only performed in the anterior vitreous cavity after the lens fragments have been safely elevated off the retina. Only surgeons experienced in vitreoretinal techniques should attempt posterior vitrectomy. In absence of capsular support, a posterior scleral fixated posterior chamber IOL, a sulcus or anterior IOL also may be placed.

Anterior Vitrectomy

Most surgeons prefer to perform anterior vitrectomyalong withprimary posteriorcapsulorhexis to decrease the incidence of posterior capsule opacification. 39,40 Anterior vitreous acts as a scaffold and helps in cellular migration and proliferation. The vitrectomy may be performed using limbal or pars plana route. In children the aim is to remove only central anterior vitreous in the posterior capsulotomy opening.41

Lensectomy in Diabetics

In diabetic patients with proliferative retinopathy, lensectomy may improve intraoperative visualization or help to gain access to peripheral fibrovascular plaques. According to Dean Eliott, MD from the Kresge Eye Institute at Wayne State University in Detroit, eyes that underwent lensectomy had less postoperative rubeosis than eyes that remained phakic. Eyes that underwent lensectomy typically had more advanced disease; however, they were able to receive more thorough treatment and actually had a lower incidence of postoperative rubeosis.42

These can be explained since lensectomy enables more complete removal of anterior vitreous and membranes. After lensectomy, usually you are able to perform careful scleral depression, dissect the vitreous base, and use endolaser and/or the laser-indirect ophthalmoscope to perform thorough photocoagulation from the arcades to the ora serrata.

Complications

The most common intraoperative complications are vitreous hemorrhages and small lens dropping falling into the vitreous cavity. Some of these are usually retrieved after careful vitrectomy.43 Accidental sphincterectomy may also occurr with the cutter probe, but this did not cause any significant optical or cosmetic problems. Iritis and transient glaucoma may be presented in the postoperative period.

References

1.Freeman W. Vitrectomy surgery for full-thickness macular holes. Am J Ophthalmol 1993; 116:233-5.

2.La Cour M, Friis J. Macular holes: classification, epidemiology, natural history and treatment. Acta Ophthalmol Scand 2002; 80:579-87.

3.Freeman WR, Azen SP, Kim JW, et al. Vitrectomy for the treatment of full-thickness stage 3 or 4 macular holes. Results of a multicentered randomized clinical trial. The Vitrectomy for Treatment of Macular Hole Study Group. Arch Ophthalmol 1997; 115:11-21.

4.Kelly NE, Wendel RT. Vitreous surgery for idiopathic macular holes: Results of a pilot study. Arch Ophthalmol 1991; 109:654-659.

5.Pertile G, Claes C. Silicone oil vs. gas for the treatment of full-thickness macular hole. Bull Soc Belge Ophtalmol 1999; 274:31-6.

6.Goldbaum MH, McCuen BW, Hanneken AM, et al. Silicone oil tamponade to seal macular holes without position restrictions. Ophthalmology 1998; 105:2140-7.

7.Lai JC, Stinnett SS, McCuen BW. Comparison of silicone oil versus gas tamponade in the treatment of idiopathic full-thickness macular hole. Ophthalmology 2003; 110:1170-4.

8.Couvillion SS, Smiddy WE, Flynn HW Jr, et al. Outcomes of surgery for idiopathic macular hole: a case-control study comparing silicone oil with gas tamponade. Ophthalmic Surg Lasers Imaging 2005; 36:365-71.

9.Chung J, Spaide R. Intraretinal silicone oil vacuoles after macular hole surgery with internal limiting membrane peeling. Am J Ophthalmol 2003; 136:766- 7.

10.Thompson JT, Smiddy WE, Glaser BM, et al. Intraocular tamponade duration and success of macular hole surgery. Retina 1996; 16:373-82.

11.Krohn J. Duration of face-down positioning after macular hole surgery: a comparison between 1 week and 3 days. Acta Ophthalmol Scand 2005; 83:289-92.

12.Isomae T, Sato Y, Shimada H. Shortening the duration of prone positioning after macular hole surgerycomparison between 1-week and 1-day prone positioning. Jpn J Ophthalmol 2002; 46:84-8.

13.Ezra E, Gregor ZJ. Moorfields Macular Hole Study Group Report No. 1. Surgery for idiopathic full-thickness macular hole: two-year results of a randomized clinical trial comparing natural history, vitrectomy, and vitrectomy plus autologous serum: Moorfields Macular Hole Study Group Report No. 1. Arch Ophthalmol 2004; 122:224-36.

14.Trese MT, Williams GA, Hartzer MK. A new approach to stage 3 macular holes. Ophthalmology 2000; 107:1607-11.

15.Saito Y, Tano Y. Intraoperative adjunctive agents in vitrectomy: serum, cytokines, and glue. Semin Ophthalmol 2000; 15:36-43.

23.Mester V, Kuhn F. Internal limiting membrane removal in the management of full-thickness macular holes. Am J Ophthalmol 2000; 129:769-77.

24.Kimura T, Takahashi M, Takagi H, et al. Is removal of internal limiting membrane always necessary during stage 3 idiopathic macular hole surgery? Retina 2005; 25:54-8.

25.Alpatov S. Is removal of internal limiting membrane always necessary during stage 3 idiopathic macular hole surgery? Retina 2005; 25:949, author reply.

26.Cheung CM, Munshi V, Mughal S, et al. Anatomical success rate of macular hole surgery with autologous platelet without internal-limiting membrane peeling. Eye 2005; 19:1191-3.

27.Kadonosono K, Itoh N, Uchio E, et al. Staining of internal limiting membrane in macular hole surgery. Arch Ophthalmol 2000; 118:1116-8.

threateningcomplicationsofsurgeryforfull-thickness macular holes. Vitrectomy for Macular Hole Study Group. Ophthalmology 1997; 104:1442-52.

17.Paques M, Chastang C, Mathis A, et al. Effect of autologous platelet concentrate in surgery for idiopathic macular hole: results of a multicenter, double-masked, randomized trial. Platelets in Macular Hole Surgery Group. Ophthalmology 1999; 106:932-8.

18.Olsen TW, Sternberg P Jr, Capone A Jr, et al. Macular hole surgery using thrombin-activated fibrinogen and selective removal of the internal limiting membrane. Retina 1998; 18:322-9.

19.Thompson JT, Smiddy WE, Williams GA, et al. Comparison of recombinant transforming growth factor-beta-2 and placebo as an adjunctive agent for macular hole surgery. Ophthalmology 1998; 105:700-6.

20.Korobelnik JF, Hannouche D, Belayachi N, et al. Autologous platelet concentrate as an adjunct in macular hole healing: a pilot study. Ophthalmology 1996; 103:590-4.

21.Kuhn F. Point: to peel or not to peel, that is the question. Ophthalmology 2002; 109:9-11.

22.Hassan TS, Williams GA. Counterpoint: to peel or not to peel: is that the question? Ophthalmology 2002; 109:11-2.

after indocyanine green and trypan blue assisted internal limiting membrane peeling during macular hole surgery. Br J Ophthalmol 2005; 89:420-4.

29.Gale JS, Proulx AA, Gonder JR, et al. Comparison of the in vitro toxicity of indocyanine green to that of trypan blue in human retinal pigment epithelium cell cultures. Am J Ophthalmol 2004; 138:64-9.

30.Karacorlu M, Ozdemir H, Arf Karacorlu S. Does intravitreal triamcinolone acetonide-assisted peeling of the internal limiting membrane effect the outcome of macular hole surgery? Graefes Arch Clin Exp Ophthalmol 2005; 243:754-7.

31.Spaide RF. Macular hole repair with minimal vitrectomy. Retina 2002; 22:183-6.

32.Ellis JD, Malik TY, Taubert MA, et al. Surgery for full-thickness macular holes with short-duration prone posturing: results of a pilot study. Eye 2000; 14:307-12.

33.Simon JW, Mehta N, Simmons ST, et al. Glaucoma after pediatric lensectomy/vitrectomy. Ophthalmology. 1991:98:670-74.

34.Kain HL, Osusky R. Pars plana lensectomy in pediatric cataract. Klin Monatsbl Augenheilkd. 1992;200(5):451-53.

35.Basti S, Ravishankar U, Gupta S. Results of a prospective evaluation of three methods of management of pediatric cataracts. Ophthalmology. 1996;103:713-20.

Introduction

Retinectomies (excision of the retina) and retinotomies (full thickness incision of the retina) can be generically classified into two main functions in vitreoretinal surgery: (1) access to the subretinal space and (2) relaxing contracted retina. Access retinotomies are frequently used to drain subretinal fluid (drainage retinotomy) from the subretinal space. They can be conveniently used to reach the subretinal space for removal of subretinal fibrosis bands or a choroidal neovascular membrane.

Subretinal membranes in proliferative vitreoretinopathy can take the form of a band, a sheet, or napkin ring configuration. Retinal detachments with PVR will fail to attach due to these subretinal membranes if they are not removed or relaxed. Small access retinotomies must be made to remove subretinal bands if it exerts significant traction. In the case of a subretinal sheet or napkin ring, the creation of a more extensive retinotomy or retinectomy, with the retina folded back on itself may be required to expose the membranes for careful

dissection away from the undersurface of the retina or attachments to the RPE.

Certaincomplexretinaldetachmentsrequire relaxing-type retinotomy and/or retinectomy to achieve a satisfactory reattachment. In the event of retinal incarceration or retinal contraction from fibrous proliferation, a relaxing retinotomy or retinectomy is often attempted as a last resort to relieve the retinal traction after other methods, such as scleral buckling and vitrectomy with peeling of epiand sub -retinal membranes, have failed. This technique was first reported by Machemer and colleagues in a case of retinal incarceration in a traumatic scleral wound.1,2 Zivojnovic et al described the use of relaxing retinotomy to relieve severe retinal traction in cases of non-traumatic fibrous proliferation.3,4 Parke and Aaberg further expanded the role of retinotomy in proliferative vitreoretinopathy (PVR).5,6 When considering such a procedure, the benefit of preserving the posterior pole should be weighed against the loss of the peripheral retinal function through a retinotomy. The size of a retinotomy may vary from a small defect to drain subretinal fluid to 360o excision of the peripheral retina. In

this chapter, we will review the indications, surgical techniques and complications of relaxing retinectomy and retinotomy in the setting of retinal detachment repair.

Indications

Proliferative vitreoretinopathy (PVR)

Focal starfold Diffuse contraction

Circumferential contraction Anterior retinal displacement Giant retinal tear

Subretinal membranes

Proliferative vascular retinopathy/Proliferative diabetic retinopathy

Longstanding fibrovascular proliferation Anterior hyaloidal fibrovascular proliferation

Retinal incarceration

Penetrating trauma Surgical sclerotomy site

Pathogenesis

PVR is the leading cause of failure in retinal detachment surgery. Retinal pigment epithelial (RPE) cells that are liberated at the time of the original retinal detachment or at the time of repair are considered to be responsible for the occurrence of PVR.7,8 The RPE cells presumably undergo fibroblastic proliferation and transform into tissue macrophages. With the ability to mature into fibrocytes, synthesize collagen and produce a membrane, they create vitreal-retinal contraction and eventually lead to retinal detachment.9,10 Despite aggressive membrane dissection, severe retinal foreshortening prevents adequate retinal reattachment to the underlying RPE layer.

In contrast, in traumatic or surgical retinal detachment with retinal incarceration, true retinal foreshortening occurs due to loss of retinal tissue. In addition, fibrous proliferation at the site of injury may further exacerbate the contraction and retinal foreshortening.

Surgical Procedures

When encountering retinal detachment with traction, the decision whether to perform a retinectomy or to place a scleral buckle alone is made at the time of surgery. An inability to flatten the retina during air-fluid exchange after careful membrane dissection indicates the need for a relaxing retinotomy or retinectomy. The location and severity of the traction are important factors to consider in making operating decisions.

Since most traction can be relieved or minimized using a scleral buckle, it is recommended that the eye be encircled with a scleral buckle at the time of retinectomy. Michels et al reported that scleral buckling reduces the vector force exerted by the epiretinal membrane on the retina, thereby reducing traction.11 The contraction of the epiretinal membrane produces a vector force perpendicular to the vitreous base and pulls the retina away from the underlying RPE (Figure 1). When a scleral buckle is placed under an area of traction, it changes the shape of the eye wall from concave to convex. This change reverses the direction of the perpendicular vector force by the epiretinal membrane, shifting it back towards the underlying RPE.

Extensive membrane dissection is important in relieving the residual traction. Minimizing any residual fibrous membranes can decrease significantly the likelihood of

Figure 1: The contraction of an epiretinal membrane produces a perpendicular vector force towards the vitreous base and pulls the retina away from the underlying retinal pigment epithelium.

recurrent detachment. Posterior membranes are easier to remove due to better visualization and access, making posterior relaxing retinectomies or retinotomies rarely indicated. In special cases with persistence of fibrous traction despitescleralbuckling and membrane dissection, retinectomies or retinotomies are needed to facilitate successful reattachment.

The location of a retinotomy may be anterior or rarely, posterior. A more anterior retinotomy has the advantages of preserving retinal function and minimizing significant hemorrhage. It is, however, technically more difficult. On the other hand, a posterior retinotomy is easier to perform, does not require lensectomy and usually allows satisfac-

Retinectomies and Retinotomies

461

tory reattachment anterior to the retinotomy site.

Perfluorocarbon liquids (PFCL) can be used as a diagnostic tool to assess areas of remaining traction thereby determining the need and extent of the retinotomy. In addition, the property of perfluorocarbon liquids (colorless, optical clarity, high density, and low viscosity) have given it popularity as a surgical adjunct or “third hand” during delicate delamination of membranes.

If the retina fails to flatten or if the PFCL moves subretinally after the initial retinotomy with the PFCL in the posterior retina, the retinotomy should be extended until the remaining retina reapposes to the underlying RPE. The retinal flattening should occur with PCFL rather than air or gas because the latter has a greater surface tension and provides tamponade for as long as it remains in the eye. An artifactually reapposed retina will detach once the air or gas absorbs.

The use of a wide-angle viewing system facilitates the visualization and assessment of the overall status of the anterior retina.12 It allows the surgeon to determine the extent of the retinectomy needed and to ensure adequate relief of traction. The following clinical examples will address the different surgical techniques of retinotomies and retinectomies according to the indications.

PROLIFERATIVE

VITREORETINOPATHY (PVR)

1. Focal Starfold (Figure 2)

After a 360o application of diathermy to the area of proliferation with extension to the

Figure 2: Focal Starfold. (a) Diathermy applied surrounding the center of proliferation. A retinotomy hole created. (b) Surrounding retina attached after removal of focal contraction. Endolaser applied to the edges of retinal defects.

surrounding normal retina, a retinotomy hole may be created using either the diathermy or an intraocular scissors. Care should be taken not to damage the underlying RPE and choriocapillaris by the diathermy or scissor tips in the area of closely apposed retina to the RPE. Significant intraocular hemorrhage may occur as a result. Following diathermy, an illuminated pick or scissors blade is used to enter the subretinal space in the area of

the greatest elevation. The retina is then elevated and separated away from the RPE before dissection. This may also be accomplished using the aspiration function of the vitrector, lifting the retina away from the underlying RPE before safely switching to cutting mode. In case of intraocular hemorrhage due to inadequate diathermy when cutting the retina, an illumination/coagulation or illumination/coagulation/suction (threeway tissue manipulator) instrument may be used to achieve hemostasis.

Following complete removal of the area of fibrous proliferation, endolaser is used to treat the edges of the retinal defects. Long-acting gas or silicone oil13 is used for tamponade.

2. Diffuse Contraction (Figure 3)

In the event of large retinal defects with diffuse contraction, two or more rows of treatment by either diathermy or endolaser may be used to completely encircle the defect with extension to the surrounding normal retina. It is often necessary to extend the coagulation to the ora serrata when proliferation involves the vitreous base.

Following adequate diathermy, the subretinal space is entered in any area of elevation without damaging the underlying choriocapillaris. A two-function (illumination/coagulation) or three-function (illumination/coagulation/suction) instrument is used for prompt hemostasis.

Following complete removal of the proliferative membrane and relief of the retinal shortening, endolaser is used to treat the edges of the retinal defect. Due to minimum collateral circulation, the remaining