Information Statement*
The Repair of Rhegmatogenous Retinal Detachments AMERICAN ACADEMY OF OPHTHALMOLOGY * The purpose of the Committee on Ophthalmic Procedures Assessment is to evaluate on a scientific basis new and existing ophthalmic tests, devices, and procedures for their safety, efficacy, clinical effectiveness and appropriate uses. Evaluations include examination of available literature, epidemiological analyses when appropriate, and compilation of opinions from recognized experts and other interested parties. After appropriate review by all contributors, including legal counsel, documents are submitted to the Academy's Board of Directors for consideration as official Academy policy.
INTRODUCTION Retinal detachments are the result of separation of the sensory retina from the retinal pigment epithelium (RPE). Retinal detachments generally lead to severe visual loss if not successfully treated. There are three major types of retinal detachments: 1) Rhegmatogenous retinal detachments are caused by a tear or hole in the retina. 2) Traction retinal detachments are a result of traction to the retina from the vitreous or fibrous tissue proliferation which pulls on the surface of the retina, detaching it from the RPE. 3) Exudative retinal detachments are caused by fluid exudation into the subretinal space from various retinalvascular or choroidal diseases such as intraocular inflammation, vascular abnormalities or tumors. Rhegmatogenous retinal detachments occur in approximately 1 in 10,000 persons per year. I In over half of these eyes, the rhegmatogenous retinal detachment occurs spontaneously, with no history of surgical or nonsurgical trauma.v' The pathogenesis of retinal breaks which cause rhegmatogenous retinal detachments includes the development of a posterior vitreous detachment which may cause retinal tears by traction on the retina. Rhegmatogenous retinal detachments may also be caused by Prepared by the Committee on Ophthalmic Procedures Assessment and approved by the Academy's Board of Directors on June 24, 1990.
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atrophic retinal holes, such as found in lattice degeneration, or by ocular trauma. Vitreous cavity fluid then passes through the tear causing detachment of the sensory retina from the RPE. The retinal detachment is maintained and enlarged by continued passage of vitreous fluid through the retinal break into the subretinal space more rapidly than the RPE is able to absorb the subretinal fluid. Retinal reattachment with the use of cryopexy, diathermy or laser in conjunction with indentation of the sclera by the placement of a scleral buckle, or retinal reattachment surgery with the use of pneumatic retinopexy are the treatment modalities used for repair of most rhegmatogenous retinal detachments. Retinal detachment repairs are usually performed by ophthalmologists who have completed one to two years of subspecialty retina training after an ophthalmology residency although some ophthalmologists combine general ophthalmic practices with a subspecialty interest in retinal diseases. Some general ophthalmologists perform straightforward retinal detachment repairs but refer more complicated retinal detachments to a retina specialist. Post-residency fellowships in diseases and surgery of the retina and vitreous have evolved over the past twenty years as a result of technological advances in the diagnosis and treatment of vitreoretinal disorders. The relatively small numbers of patients with retinal detachments in general ophthalmology practices encourages referral to specialists skilled in these techniques. This is reflected in statistics from the American College of Graduate Medical Edu-
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cation which show that the average ophthalmology resident performs six retinal detachment repairs during his or her residency compared to twenty-six strabismus procedures and ninety-nine cataract extractions." There are three basic steps in repairing rhegmatogenous retinal detachments with a scleral buckle. The first step is the precise localization of all of the retinal breaks in the detached retina. The second step is creation of a chorioretinal adhesion around the retinal break(s). The third step is placement of a scleral buckle to indent the eyewall toward the retinal break and relieve vitreoretinal traction on the break. The scleral buckling material is made of silicone sponge or solid silicone rubber that is either sutured to the outside of the sclera (exoplant) or placed in a pocket within the sclera (implant). In many instances subretinal fluid is drained externally to help reappose the retinal break to the scleral buckle. Currently, scleral buckling procedures are used to repair most rhegmatogenous retinal detachments. Alternative procedures for repair of retinal detachments without use of scleral buckles, such as pneumatic retinopexy, are used in place of a scleral buckle in some eyes. This manuscript will review the indications, preoperative evaluation, operative technique, postoperative care, results and complications of the repair of rhegmatogenous retinal detachments.
INDICATIONS FOR THE USE OF SCLERAL BUCKLES THE PROPHYLACTIC TREATMENT OF RETINAL BREAKS WITHOUT RETINAL DETACHMENT
Retinal breaks, in the absence of significant retinal detachment, can be successfully treated without the use of a scleral buckle. Cryopexy or laser photocoagulation, usually performed in the ophthalmologist's office or in an outpatient surgical facility, induces a chorioretinal adhesion around the break, thereby preventing retinal detachment. It is sometimes necessary to make conjunctival incisions in order to place cryopexy around posterior retinal breaks. A sterile operative procedure must be used if conjunctival incisions are made. Some retinal breaks are surrounded by a small area of subretinal fluid, forming a subclinical or limited retinal detachment. INDICATIONS FOR THE USE OF A SCLERAL BUCKLE
If the amount of surrounding fluid is small, then laser photocoagulation or cryopexy can be used to surround the retinal detachment. 5 The decision about the efficacy of laser photocoagulation or cryopexy in eyes with limited retinal detachment must be dictated by a careful clinical examination of the type of tear, the size of the retinal detachment, the vitreoretinal pathology, the status of the fellow eye and the general health of the patient. If laser photocoagulation or cryopexy alone is not sufficient to treat a limited rhegmatogenous retinal detachment, then retinal reattachment surgery with placement of a scleral buckle is usually indicated. Alternative procedures to a
scleral buckle include pneumatic retinopexy" and vitrecto my with or without scleral buckle." which may be employed in certain circumstances. The decision concerning optimal treatment must be made by the surgeon and the recommendations discussed with the patient after a thorough examination has been performed.
PREOPERATIVE EVALUATION The preoperative evaluation of the patient with a retinal tear or rhegmatogenous retinal detachment begins with an ophthalmologic history ofthe current problem and the circumstances surrounding the current symptoms. Questions concerning predisposing factors such as myopia, previous ocular trauma or previous ocular surgery are included in the ophthalmologic history as well as details concerning the onset of symptoms such as photopsias, floaters, constricted peripheral field or decreased vision. The patient is questioned about the presence of other known ocular diseases. A medical history is performed to determine if there are any systemic illnesses or ocular diseases which could impact on the surgical repair of the retinal detachment. This is followed by an ophthalmologic examination which includes external examination, pupils, visual fields, ocular motility, ocular deviation, anterior segment examination with a slit lamp, intraocular pressure measurement and fundus examination of both eyes with indirect ophthalmoscopy and scleral depression. Biomicroscopy of the fundus with a contact lens is frequently helpful. Salient features of the fundus examination are carefully recorded on a fundus drawing. Particular attention is paid to the location, number, size and characteristics of each retinal break, for this, in large measure, determines the best surgical approach. Attention must also be given to factors which may limit or impair the ability to perform the retinal detachment repair such as inadequate pupillary dilation, opacities in the normally transparent ocular media (cornea, lens or vitreous opacities), external infection, previous surgical scarring, glaucoma and coexisting choroidal detachment. The status of the lens is noted since the surgical technique may have to be modified in eyes with previous lens removal or in eyes with an intraocular lens implant. The results of the examination are discussed with the patient, including the rationale for surgery, realistic goals of surgery, the type ofanesthesia, risks of surgery, possible complications, duration of convalescence, possible need for reoperations, and possible functional limitations after surgery such as incomplete visual recoveryor strabismus. The possibility that the retina may be successfully reattached by the surgery (anatomic success) but may never regain useful vision (functional failure) should be discussed. Binocular patching of the eyes and/or bedrest are sometimes utilized preoperatively to limit the spread of the retinal detachment or to promote absorption of subretinal fluid prior to the retinal detachment repair. A presurgical medical examination is performed to evaluate any systemic illnesses which may impact on the method of anesthesia or surgery. 1563
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TIMING OF SURGERY Retinal tears may progress to retinal detachments within hours to days. Hence, when a retinal tear is found, treatment is usually performed the same day or within a few days depending on the surgeon's assessment of the risk of the retinal tear progressing to a rhegmatogenous retinal detachment. If a rhegmatogenous retinal detachment is present, the presence or absence of macular detachment is the major determinant of the urgency of repair of the detachment. If the macula is attached, the following guidelines may be used. 1) The retinal detachment repair is performed within a few days to a week if the detachment is in the periphery and does not have features which suggest rapid progression. 2) The retinal detachment repair should be done as soon as possible, preferably within 24 hours if the detachment is close to the macula. 3) The retinal detachment repair may be done within several hours of diagnosis by the retinal surgeon if the macula is imminently threatened by the detachment or if the detachment is secondary to a giant retinal tear (a retinal tear 90 degrees or greater in extent). If the macula is detached, the following guidelines may be used. 1) The retinal detachment repair is usually done within one to two days if the macula became detached a few days prior to presentation to the surgeon's office. Increased macular function may be regained if the recently detached macula is promptly reattached. 2) The retinal detachment repair may be performed electively within a week or two if the detachment is chronic and has already involved the macula. The timing of retinal reattachment surgery also depends on other features of the ophthalmic and medical examination which must be considered in addition to the status of the macula.
TECHNIQUE FOR RETINAL DETACHMENT REPAIR
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is generally advisable to have an anesthesiologist or anesthetist on standby for retinal detachment repairs performed using local anesthesia because the duration of surgery may be unpredictable, prolonged sedation may be needed, the patient's vital signs must be monitored and occasionally the local anesthesia may have to be converted to general anesthesia because of poor patient cooperation. The major disadvantages of local anesthesia are the risks of retrobulbar anesthetic injection, inadequate pain control and patient anxiety with the inability of some patients to cooperate for the duration of the surgery. General anesthesia has the advantage of immobility of the patient and complete pain control during surgery which is especially helpful for long procedures or reoperations. The major disadvantages of general anesthesia include prolonged recovery time and increased systemic risks. The surgeon is in the best position to discuss the optimal form of anesthesia with the patient after the history and examination have been completed, since the risks and benefits of local versus general anesthesia can be evaluated better at that time. PREPARATION OF THE EYE FOR RETINAL DETACHMENT REPAIR
The pupil must be dilated using one or more topical mydriatic medications such as tropicamide, phenylephrine, homatropine or cyclopentolate prior to retinal detachment repair. Some surgeons use preoperative topical antibiotics to decrease the normal bacterial flora on the external eye. The eyelashes may be trimmed preoperatively to decrease the risk oflashes contaminating the surgical field. The eyelids are cleansed in the operating room with topical antimicrobial solution on the eyelids and face surrounding the eye. The operative field is then covered with sterile drapes and the eyelids are kept open with a lid speculum. A lateral canthotomy may be needed in some eyes with tight eyelids or when better exposure of the posterior globe is needed. OPERATIVE PROCEDURE8 ,9,1O,1I ,12
ANESTHESIA
The decision whether to perform surgery for retinal detachment under local anesthesia or general anesthesia is determined by the surgeon and patient in consultation with a medical specialist when severe cardiovascular or cardiopulmonary disease is present. The surgeon must provide guidance about what type of anesthetic is most appropriate based on the estimated duration of the surgery, the patient's ability to cooperate with local anesthesia and the risk of general anesthesia in that patient. A primary, uncomplicated retinal detachment repair may require one to two hours. Reoperations or complicated retinal detachments may require as much as four to five hours. Some retinal surgeons perform a majority of their surgery under local anesthesia while other surgeons perform a majority of their surgery using general anesthesia. Local anesthesia has the advantage ofless systemic risk to the patient, decreased total operating room time, and more rapid postoperative recovery from the anesthetic. It 1564
A conjunctival peritomy is performed to expose the sclera and recti muscles. A bridle suture is placed around each of the four rectus muscles and the sclera is examined in each of the quadrants for abnormalities such as scleral staphyloma. The retina is examined by scleral depression to identify the topography of the retinal detachment and vitreoretinal interface. Any changes from the preoperative examination are noted. The retinal breaks are localized on the sclera and their location is accurately marked on the sclera with a tissue marker pen or diathermy. Each of the retinal breaks is surrounded by a type of thermal retinopexy such as cryopexy, diathermy or laser photocoagulation to create a chorioretinal adhesion between the retina and retinal pigment epithelium. Cryopexy or laser photocoagulation may be deferred until after drainage of subretinal fluid in cases where the retina is initially highly elevated above the retinal pigment epithelium. Diathermy may be used instead of cryopexy after dissection of the scleral bed if a scleral implant is to be used.
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The surgeon must then choose the size, shape and type of scleral buckle needed to adequately close all of the retinal breaks and relieve any areas of vitreoretinal traction. Scleral exoplants or implants are usually composed of one of two materials: I) " hard" (semi-flexible) solid silicone rubber or 2) "soft" (flexible) silicone rubber sponges. The silicone buckle material may be soaked in antibiotic solution before being placed around the eye to reduce the risk of infection. 13 If a scleral buckle exoplant is chosen , then the sutures are placed at appropriate locations in the sclera to anchor the scleral exoplant. If intrascleral buckling is chosen using a scleral buckle implant, then a lamellar dissection of the sclera is performed to create a pocket to hold the implant in position. Occasionally, extraocular muscles are temporarily disinserted to allow placement of the scleral buckle under an extraocular muscle. Diathermy may be used to create the chorioretinal adhesion instead of cryopexy when lamellar dissection of the scleral bed is performed in eyes treated with a scleral buckle implant. Many surgeons prefer scleral buckle exoplants since the use of exoplants avoids lamellar scleral dissection which increases the duration of surgery, exoplants are less likely to intrude into the eye and reoperations with revision of the buckle are less likely to cause scleral rupture. Some surgeons prefer intrascleral implants because they have the advantage of avoiding placement of anchoring scleral sutures which can perforate the globe. Scleral implants are also less likely to extrude through the conjunctiva to become exposed. Subretinal fluid may be drained depending on the location and height of the retinal detachment. Some surgeons drain subretinal fluid in most cases while other surgeons rarely drain subretinal fluid but may use other modalities such as intravitreal gas injections to tamponade the retinal breaks internally. The success of retinal reattachment is similar in drainage versus nondrainage procedures.!" In eyes where drainage of subretinal fluid is planned, the fundus is examined to identify a site with adequate subretinal fluid to allow safe drainage of subretinal fluid. Transillumination or placement of the drainage site near the horizontal recti may be used to try to avoid making the scleral drainage incision over any large choroidal vessels. Drainage of subretinal fluid is usually performed by making a radial incision through the sclera to expose the choroid. The choroid may be diathermized to minimize the risk of bleeding. A diathermy needle or a sharp suture needle is used to make a small hole in the exposed choroid. Gentle pressure ma y be applied to the globe to aid in drainage of subretinal fluid. Ophthalmoscopy is performed to determine whether all of the subretinal fluid has been drained or if complications such as subretinal bleeding or retinal incarceration have occurred at the drainage site. The drainage sclerotomy may then be closed with an absorbable suture to prevent any postoperative drainage of subretinal fluid or retinal incarceration, although some surgeons prefer to leave the drainage site open if there is residual subretinal fluid. Drainage of subretinal fluid helps to immediately reappose the retina to the scleral buckle by decreasing the height of the detachment and the volume of subretinal
fluid. Drainage also lowers the intraocular pressure and compensates for the intraocular volume displacement by the scleral buckle. The scleral exoplant or implant is then secured and tightened to create an indentation or "buckle" in the sclera. Temporary knots in the sutures around the scleral buckle exoplant may be used to allow adjustment of the buckle height after examining the eye. The intraocular pressure ma y increase as the scleral buckle is tightened due to intraocular volume displacement by the scleral buckle. The fundus is examined to verify that the central retinal artery is not occluded from a high intraocular pressure. The amount of residual subretinal fluid is noted to determine whether additional drainage of subretinal fluid is desirable. The adequacy of support of the retinal tears and relief of vitreoretinal traction by the scleral buckle is evaluated. The buckle is secured permanently if temporary knots were used to secure the scleral exoplant. If the intraocular pressure remains elevated, then paracentesis of aqueous humor from the anterior chamber or in rare instances, removal of vitreous from the vitreous cavity may be performed to normalize the intraocular pressure. Some patients are given intravenous medications such as acetazolamide preoperatively or intraoperatively to suppress aqueous production. Suppressants of aqueous production lower the intraocular pressure during surgery and minimize elevation of the intraocular pressure immediately after surgery. If the eye has a very low intraocular pressure after drainage of subretinal fluid and placement of the scleral buckle, then a balanced salt solution may be injected into the eye via the pars plana to normalize the intraocular pressure. Alternatively, an intraocular gas bubble injection may be desirable to tamponade retinal breaks internally if the breaks remain elevated over the scleral buckle. Air or expansile gases such as sulfur hexafluoride (SF 6), perfluoromethane (CF4), perfluoroethane (C2F6 ) , perfluoropropane (C3Fs), perfluoron-butane (C4F IO) or octofluorocyclobutane (C4F s) are injected through the pars plana if an intraocular gas bubble is needed.P:" Antibiotic solution may be irrigated around the eye followed by closure of Tenon's capsule and the conjunctiva with absorbable sutures. Subconjunctival antibiotics and/or steroids are usuall y given, followed by topical antibiotics, topical steroids and topical mydriatics. The eye is covered with a sterile patch and protective shield prior to leaving the operating room . Several portions of the procedure such as drainage of subretinal fluid and exposure of the sclera for placement of the buckle require an assistant to be performed safely. Thus, most retinal detachment repairs with a scleral buckle are performed by the surgeon with a surgical assistant.
INTRAOPERATIVE COMPLICATIONS There are a number of intraoperative complications which may compromise the surgical objectives of the retinal detachment repair, forcing the surgeon to alter the
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basic operative technique. Potential intraoperative complications include retrobulbar hemorrhage, scleral rupture, choroidal or retinal perforation, subretinal hemorrhage, vitreous hemorrhage, choroidal detachment, retinal incarceration and central retinal artery occlusion. Retrobulbar hemorrhage or perforation of the globe may occur with use of retrobulbar anesthetic injections when performing retinal reattachment under local anesthesia.!? Scleral rupture may occur during the initial exposure of the sclera, during examination of the retina with scleral depression or placement of the scleral buckle. Scleral rupture occurs most commonly in myopic eyes with scleral staphyloma or in eyes with previous retinal detachment surgery where there is extensive scarring of the conjunctiva and Tenon's capsule to the sclera with thinning of the sclera at the site of the previous scleral buckle. Scleral rupture can be a catastrophic complication with loss of intraocular contents. The rupture must be closed to reestablish the integrity of the globe and allow continuation of the surgery. Perforation of the choroid or retina may also occur during placement of scleral sutures for a scleral buckle exoplant or during lamellar scleral dissection for an implant. Scleral perforation is most common in eyes with thin sclera due to myopia, scleral staphyloma or previous retinal detachment repair. Scleral perforation by a suture is often self-sealing once the offending suture is removed, but perforation of the choroid may cause subretinal bleeding and/or vitreous hemorrhage. Subretinal hemorrhage from choroidal bleeding may impair adequate reattachment of the retina and impair visual recovery, especially if the subretinal hemorrhage moves to the macular region. Vitreous hemorrhage from scleral and/or retinal perforation may impair the view of the retina such that completion of the retinal detachment repair is difficult. Pars plana vitrectomy may be required to remove a severe vitreous hemorrhage, thus allowing continuation of surgery. Choroidal perforation by a suture usually does not have to be treated specifically. Retinal perforation must be treated by producing a chorioretinal adhesion with cryopexy or diathermy and may require revision of the scleral buckle to support the retinal perforation site. Hemorrhagic choroidal detachment may result from choroidal perforation during placement of scleral sutures or may occur spontaneously. Non-hemorrhagic serous choroidal detachments may occur preoperatively, intraoperatively or postoperatively. Hemorrhagic and serous choroidal detachments can prevent adequate settling of the retina against the buckle postoperatively, leading to persisting retinal detachment. Drainage of subretinal fluid may be associated with multiple complications. 18 Choroidal bleeding with drainage of subretinal fluid may occur despite diathermy to the vascular choroid prior to drainage of subretinal fluid. Retinal perforation may occur if the choroid is punctured over an area of shallow retinal detachment. Drainage may then be accompanied by loss of vitreous through the retinal break with incarceration of vitreous and retina into the drainage site. Retinal incarceration may complicate drainage if the subretinal fluid drains too rapidly, pulling 1566
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the retina into the drainage site. Increasing the height of the scleral buckle may increase the intraocular pressure due to displacement of intraocular volume by the scleral buckle in nondrainage procedures or in some drainage procedures where a broad scleral buckle in used.!? The intraocular pressure must not be allowed to remain very high at the completion of the surgical procedure or central retinal artery occlusion may occur with subsequent infarction of the inner retina and profound vision loss.
POSTOPERATIVE CARE The operated eye is usually treated with a topical antibiotic, topical steroid and topical mydriatic drops starting on the first postoperative day after retinal detachment repair. The eye may be covered with a patch for one or more days after surgery until the eye is comfortable. Ambulation is encouraged as soon as possible. The patient may be discharged from the hospital one to three days after the surgery, unless there are complications, depending on the duration and complexity of the surgery as well as the medical status of the patient. Some retinal detachment repairs requiring short operative procedures under local anesthesia may be performed as an outpatient procedure although many patients require an inpatient stay to monitor vital signs, administer intravenous fluids, control pain, treat nausea, vomiting and monitor the eye for early complications such as hemorrhage, infection, elevated intraocular pressure or redetachment of the retina." The operated eye is examined daily while the patient is hospitalized to monitor the response to the surgery and to detect any complications in the early postoperative period. The patient is examined as an outpatient with the frequency of visits determined by the status of the eye after retinal detachment repair. The surgeon who performs the retinal detachment repair is responsible for the preoperative evaluation and postoperative care. Preoperative examination by the surgeon determines the type of surgical procedure required to close the retinal breaks causing the retinal detachment. Postoperative care by the surgeon allows the surgeon to monitor the success of the retinal detachment repair and to detect any postoperative complications. The surgeon will usually reexamine the patient postoperatively two or more times in the first month after the retinal detachment repair. Once the surgeon is satisfied that the eye is stable, the patient may be returned to the referring physician for further ophthalmic care. Many retinal surgeons will reexamine the patient between six and twelve months after surgery to monitor for any late postoperative complications and to examine the fellow eye which is at increased risk for a retinal tear or detachment if the operated eye had a non-traumatic retinal detachment. If the patient is unable to return to the surgeon for postoperative care due to geographical or other extenuating circumstances, the surgeon may transfer care to another ophthalmologist who is qualified to monitor the response to the retinal detachment repair.
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EARLY POSTOPERATIVE COMPLICATIONS Retinal detachment repair has an overall success rate of 90% with one or more operations." Certain complications may lead to failure of the retinal detachment repair within the first few weeks after retinal reattachment (early postoperative complications), while other types of complications generally occur one or more months after surgery (late postoperative complications). It is much less common for an eye to develop complications more than six months postoperatively, although retinal redetachment, exposure or infection of the scleral buckle may occasionally occur years later. Early postoperative complications include persisting retinal detachment, buckle exposure, buckle infection, endophthalmitis, choroidal detachment, elevated intraocular pressure, glaucoma, conjunctival adhesions and anterior segment ischemia/ necrosis. PERSISTING RETINAL DETACHMENT
If the subretinal fluid does not resorb, additional procedures such as injection of an intraocular gas bubble or laser photocoagulation as an outpatient may need to be done. It may become apparent postoperatively that the buckle is not adequately supporting the retinal breaks. Inadequate closure of retinal breaks may be due to vitreous traction, persisting bullous detachment, improper buckle position or inadequate buckle height. Redetachment of the retina may be caused by the formation of new retinal breaks. These occur most frequently in the early postoperative period. New retinal breaks occur most commonly when an intraocular gas bubble has been injected into the eye.22 ,23,24 Reoperation with revision of the scleral buckle is required if the buckle is not adequately supporting all of the retinal breaks and the situation cannot be resolved by a less invasive procedure such as an intraocular gas injection or laser photocoagulation. BUCKLE EXPOSURE OR INFECTION
Some complications may be related to the use of a scleral buckle. Exposure of the scleral buckle may occur with or without signs or symptoms of an external buckle infection. An infection of the scleral buckle is treated by removing the scleral buckle, sutures and administering topical antibiotics. Oral or intravenous antibiotics may be needed to treat a buckle infection depending on the severity of the infection. 25 ,26,27,28,29,3o,3 1 Endophthalmitis may develop from spread of an external buckle infection into the eye or may develop from inadvertent inoculation of bacteria into the eye at the time of surgery: e.g., during drainage of subretinal fluid, paracentesis or intraocular gas bubble injection. Treatment of endophthalmitis requires intravenous antibiotics, intravitreal antibiotics and usually pars plana vitrectomy depending on the severity of the infection.
CHOROIDAL DETACHMENT
Choroidal detachment results from exudation of fluid within the choroid. Choroidal detachments generally resolve within one to two months after surgery. Oral steroid therapy may hasten resolution of the choroidal detachment in a small number of eyes. Surgical drainage of the choroidal detachment may occasionally be required if the choroidal detachment is so large that it involves the macula, comes in contact with large choroidal detachment extending from the opposite side of the globe or is persistent. ELEVATED INTRAOCULAR PRESSURE
The intraocular pressure may become elevated following retinal detachment repair. Intraocular pressure elevation is usually transient and can be treated with topical or systemic inhibitors of aqueous humor formation such as topical beta blockers, oral acetazolamide or oral methazolamide. Occasionally, angle closure glaucoma results from forward displacement of the iris after an encircling scleral buckle. Closure of the anterior chamber angle causing elevated intraocular pressure may be associated with choroidal detachment and will usually resolve with cycloplegics, aqueous suppressants and topical steroids. Surgical drainage of the choroidal detachment and reformation of the anterior chamber may be required if the eye does not respond to topical medications. Peripheral iridectomy may be needed to treat angle closure glaucoma if medical treatment fails. CONJUNCTIVAL ADHESIONS
An adhesion between the palpebral and bulbar conjunctiva (symblepharon) may lead to ocular motility problems and abnormalities ofthe lids. These conjunctival adhesions can be lysed with a glass rod in the office if detected early in the postoperative course. ANTERIOR SEGMENT ISCHEMIA/NECROSIS
Anterior segment ischemia and anterior segment necrosis are serious complications of retinal detachment surgery. Anterior segment necrosis results from impaired blood flow to the anterior segment and impaired venous return of blood from the anterior segment. Anterior segment necrosis is characterized by corneal edema and abnormal intraocular pressure. The intraocular pressure may initially become elevated but the eye eventually develops hypotony. It may lead to shrinkage of the eye (phthisis bulbi). Anterior segment necrosis is most frequent in elderly patients with broad or posteriorly located encircling scleral buckles or in eyes where more than two extraocular muscles have been disinserted and reattached during surgery. Patients with sickle cell retinopathy are also at increased risk for development of anterior segment necrosis after retinal detachment repair.F Anterior segment ischemia can be treated successfully in some eyes by intensive steroid therapy or surgically by loosening the encircling scleral buckle. 1567
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LATE POSTOPERATIVE COMPLICATIONS Some of the late postoperative complications are identical to early postoperative complications. These include persisting retinal detachment from inadequately supported retinal breaks or inadequate chorioretinal adhesion surrounding one or more breaks. Reoperation with revision ofthe scleral buckle is usually required ifthe retina fails to reattach within 1 month of surgery or as soon as the surgeon is convinced that the retina will not reattach. PERSISTING VITREORETINAL TRACfION AND PROLIFERATIVE VITREORETINOPATHY
Vitreoretinal traction may prevent closure of the retinal break and reapposition of the retina to the retinal pigment epithelium, leading to a recurrence of the retinal detachment. If the vitreoretinal traction is focal, then reoperation with revision of the scleral buckle or vitrectomy can be employed. Sometimes the retina initially attaches after surgery but redetaches several weeks to months later due to cellular proliferation and contraction on the surface of the retina and vitreous base. This cellular proliferation is called proliferative vitreoretinopathy. Mild forms cellular proliferation may be treated with revision of the scleral buckle. Moderate and severe forms of proliferative vitreoretinopathy are usually treated with revision of the scleral buckle combined with pars plana vitrectomy, dissection and removal of the epiretinal proliferation, thermal retinopexy and fluid-gas exchange. Some eyes with severe proliferative vitreoretinopathy require intraocular tamponade with intravitreal silicone oil. Proliferative vitreoretinopathy is the most common cause of failed retinal detachment repair." PERSISTING SUBRETINAL FLUID
Subretinal fluid may persist in the absence of identifiable open retinal breaks. Persisting subretinal fluid is usually monitored since it will eventually resorb if there are no remaining open retinal breaks. REFRACfIVE ERRORS
Refractive errors induced by changes in the shape of the eye may occur as a result of retinal detachment repair. These refractive changes include astigmatic errors as well as changes in spherical equivalent. The spectacle or contact lens prescription will need to be changed if there is a substantial change in refraction. 33 ,34,35,36 STRABISMUS
Ocular motility disturbances may follow retinal detachment repair with a scleral buckle. 37 ,38,39 Strabismus is most common when the scleral buckle must be placed under one of the extraocular muscles. The degree ofstrabismus often improves in the first six months following retinal detachment repair, but some strabismic deviations 1568
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are permanent and may require use of prisms or surgical correction.'? CYSTOID MACULAR EDEMA
Some postoperative complications compromise the function of the macula. Cystoid macular edema is the result of extracellular intraretinal fluid accumulation in the macula which may result in decreased vision. Cystoid macular edema is relatively common following retinal detachment repair and may account for vision loss in eyes whether or not the macula was detached preoperatively. Cystoid macular edema noted postoperatively may have been present, but undetected, preoperatively. Cystoid macular edema is present to at least some degree in about 9% to 25% ofphakic eyes and 29% to 64% of aphakic eyes after retinal detachment repair. 4 1,42,43 MACULAR EPIRETINAL MEMBRANE
Another source of decreased vision after retinal detachment repair with scleral buckle is a macular epiretinal membrane, due to formation ofscar tissue on the macula. Macular epiretinal membranes have also been referred to as premacular fibrosis, surface wrinkling retinopathy, internallimiting membrane contracture and macular preretinal membranes. Epiretinal membranes occur in about 8% of eyes after retinal detachment repair." Epiretinal membranes occur as a result of cellular proliferation on the surface of the macula and may represent a mild form of proliferative vitreoretinopathy. Epiretinal membranes localized over the macula usually do not cause recurrent rhegmatogenous retinal detachment. Epiretinal membranes may cause substantial distortion of the macula with vision loss from macular distortion or cystoid macular edema." Ifthe epiretinal membrane is thought to be the principle cause for decreased postoperative vision, then pars plana vitrectomy and epiretinal membrane dissection may improve vision." INFECTION
Infection of the scleral buckle may occur shortly after retinal detachment repair or many years later. 28 ,30 Scleral buckle infection requires removal of the scleral buckle whether the infection occurs as an early or late postoperative complication. SCLERAL BUCKLE EXPOSURE OR INTRUSION
Scleral buckle exposure without evidence of infection usually requires eventual removal of the scleral buckle since exposure ofthe buckle may lead to infection. Scleral buckles may occasionally intrude into the eye, although this has become less frequent with improvements in scleral buckling materials and techniques." CATARACf
Cataracts may develop or progress more rapidly in eyes after retinal detachment repair. Cataract extraction may
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be required to restore vision and to allow continued examination of the retina. In general, cataract extraction is avoided for at least several months after retinal detachment repair to allow a maximal chorioretinal adhesion to form around the retinal break(s) before subjecting the eye to additional surgery. PHTHISIS BULBI
Phthisis bulbi with hypotony may follow retinal detachment repair leading to shrinkage of the globe and opacification of the cornea with vascularization. Phthisis may be the result of persisting retinal detachment, anterior segment ischemia, excessive postoperative inflammation with hypotony, choroidal detachment or may occur for no apparent reason. Most or all vision is lost in eyes that develop phthisis bulbi. Eyes must be monitored carefully after retinal detachment repair to detect and try to treat postoperative complications that can lead to irreversible damage to the eye.
THE RESULTS OF RETINAL DETACHMENT REPAIR The anatomic and visual success rates of retinal detachment repair have gradually improved over the past decades as a result of improved surgical techniques, improved materials and an improved understanding of the pathophysiology of retinal detachment. Anatomic success is usually defined as reattachment of the retina posterior to the scleral buckle. Anatomic success is an important measure of success since anatomic success usually confers long term stability to the retina and visual acuity. Functional success with retinal detachment repair is determined by the best corrected visual acuit y obtained six months or more after the retinal detachment repair. Some eyes have an anatomically successful retinal detachment repair but have functional failure due to very poor postoperative VISIOn.
ANATOMIC SUCCESS
With current techniques about 90% of retinal detachments can be successfully reattached with one or more operations.v":" The anatomic success rate however is dependent on the preoperative pathology causing the retinal detachment. Retinal detachments due to small atrophic holes, retinal dialyses and horseshoe tears have an excellent prognosis with a success rate ofover 95%.9,48,49 Retinal detachment repair in aphakic eyes without intraocular lenses has a success rate between 88% and 96%.9.50 Retinal detachment repair in eyes with anterior chamber intraocular lenses has a success rate of about 69% with one operation." The success rate increases to approximatcly 83% with one or more surgical procedures.P'
The Repair of Rhegmatogenous Retinal Detachments AMERICAN ACADEMY OF OPHTHALMOLOGY * The purpose of the Committee on Ophthalmic Procedures Assessment is to evaluate on a scientific basis new and existing ophthalmic tests, devices, and procedures for their safety, efficacy, clinical effectiveness and appropriate uses. Evaluations include examination of available literature, epidemiological analyses when appropriate, and compilation of opinions from recognized experts and other interested parties. After appropriate review by all contributors, including legal counsel, documents are submitted to the Academy's Board of Directors for consideration as official Academy policy.
INTRODUCTION Retinal detachments are the result of separation of the sensory retina from the retinal pigment epithelium (RPE). Retinal detachments generally lead to severe visual loss if not successfully treated. There are three major types of retinal detachments: 1) Rhegmatogenous retinal detachments are caused by a tear or hole in the retina. 2) Traction retinal detachments are a result of traction to the retina from the vitreous or fibrous tissue proliferation which pulls on the surface of the retina, detaching it from the RPE. 3) Exudative retinal detachments are caused by fluid exudation into the subretinal space from various retinalvascular or choroidal diseases such as intraocular inflammation, vascular abnormalities or tumors. Rhegmatogenous retinal detachments occur in approximately 1 in 10,000 persons per year. I In over half of these eyes, the rhegmatogenous retinal detachment occurs spontaneously, with no history of surgical or nonsurgical trauma.v' The pathogenesis of retinal breaks which cause rhegmatogenous retinal detachments includes the development of a posterior vitreous detachment which may cause retinal tears by traction on the retina. Rhegmatogenous retinal detachments may also be caused by Prepared by the Committee on Ophthalmic Procedures Assessment and approved by the Academy's Board of Directors on June 24, 1990.
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atrophic retinal holes, such as found in lattice degeneration, or by ocular trauma. Vitreous cavity fluid then passes through the tear causing detachment of the sensory retina from the RPE. The retinal detachment is maintained and enlarged by continued passage of vitreous fluid through the retinal break into the subretinal space more rapidly than the RPE is able to absorb the subretinal fluid. Retinal reattachment with the use of cryopexy, diathermy or laser in conjunction with indentation of the sclera by the placement of a scleral buckle, or retinal reattachment surgery with the use of pneumatic retinopexy are the treatment modalities used for repair of most rhegmatogenous retinal detachments. Retinal detachment repairs are usually performed by ophthalmologists who have completed one to two years of subspecialty retina training after an ophthalmology residency although some ophthalmologists combine general ophthalmic practices with a subspecialty interest in retinal diseases. Some general ophthalmologists perform straightforward retinal detachment repairs but refer more complicated retinal detachments to a retina specialist. Post-residency fellowships in diseases and surgery of the retina and vitreous have evolved over the past twenty years as a result of technological advances in the diagnosis and treatment of vitreoretinal disorders. The relatively small numbers of patients with retinal detachments in general ophthalmology practices encourages referral to specialists skilled in these techniques. This is reflected in statistics from the American College of Graduate Medical Edu-
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cation which show that the average ophthalmology resident performs six retinal detachment repairs during his or her residency compared to twenty-six strabismus procedures and ninety-nine cataract extractions." There are three basic steps in repairing rhegmatogenous retinal detachments with a scleral buckle. The first step is the precise localization of all of the retinal breaks in the detached retina. The second step is creation of a chorioretinal adhesion around the retinal break(s). The third step is placement of a scleral buckle to indent the eyewall toward the retinal break and relieve vitreoretinal traction on the break. The scleral buckling material is made of silicone sponge or solid silicone rubber that is either sutured to the outside of the sclera (exoplant) or placed in a pocket within the sclera (implant). In many instances subretinal fluid is drained externally to help reappose the retinal break to the scleral buckle. Currently, scleral buckling procedures are used to repair most rhegmatogenous retinal detachments. Alternative procedures for repair of retinal detachments without use of scleral buckles, such as pneumatic retinopexy, are used in place of a scleral buckle in some eyes. This manuscript will review the indications, preoperative evaluation, operative technique, postoperative care, results and complications of the repair of rhegmatogenous retinal detachments.
INDICATIONS FOR THE USE OF SCLERAL BUCKLES THE PROPHYLACTIC TREATMENT OF RETINAL BREAKS WITHOUT RETINAL DETACHMENT
Retinal breaks, in the absence of significant retinal detachment, can be successfully treated without the use of a scleral buckle. Cryopexy or laser photocoagulation, usually performed in the ophthalmologist's office or in an outpatient surgical facility, induces a chorioretinal adhesion around the break, thereby preventing retinal detachment. It is sometimes necessary to make conjunctival incisions in order to place cryopexy around posterior retinal breaks. A sterile operative procedure must be used if conjunctival incisions are made. Some retinal breaks are surrounded by a small area of subretinal fluid, forming a subclinical or limited retinal detachment. INDICATIONS FOR THE USE OF A SCLERAL BUCKLE
If the amount of surrounding fluid is small, then laser photocoagulation or cryopexy can be used to surround the retinal detachment. 5 The decision about the efficacy of laser photocoagulation or cryopexy in eyes with limited retinal detachment must be dictated by a careful clinical examination of the type of tear, the size of the retinal detachment, the vitreoretinal pathology, the status of the fellow eye and the general health of the patient. If laser photocoagulation or cryopexy alone is not sufficient to treat a limited rhegmatogenous retinal detachment, then retinal reattachment surgery with placement of a scleral buckle is usually indicated. Alternative procedures to a
scleral buckle include pneumatic retinopexy" and vitrecto my with or without scleral buckle." which may be employed in certain circumstances. The decision concerning optimal treatment must be made by the surgeon and the recommendations discussed with the patient after a thorough examination has been performed.
PREOPERATIVE EVALUATION The preoperative evaluation of the patient with a retinal tear or rhegmatogenous retinal detachment begins with an ophthalmologic history ofthe current problem and the circumstances surrounding the current symptoms. Questions concerning predisposing factors such as myopia, previous ocular trauma or previous ocular surgery are included in the ophthalmologic history as well as details concerning the onset of symptoms such as photopsias, floaters, constricted peripheral field or decreased vision. The patient is questioned about the presence of other known ocular diseases. A medical history is performed to determine if there are any systemic illnesses or ocular diseases which could impact on the surgical repair of the retinal detachment. This is followed by an ophthalmologic examination which includes external examination, pupils, visual fields, ocular motility, ocular deviation, anterior segment examination with a slit lamp, intraocular pressure measurement and fundus examination of both eyes with indirect ophthalmoscopy and scleral depression. Biomicroscopy of the fundus with a contact lens is frequently helpful. Salient features of the fundus examination are carefully recorded on a fundus drawing. Particular attention is paid to the location, number, size and characteristics of each retinal break, for this, in large measure, determines the best surgical approach. Attention must also be given to factors which may limit or impair the ability to perform the retinal detachment repair such as inadequate pupillary dilation, opacities in the normally transparent ocular media (cornea, lens or vitreous opacities), external infection, previous surgical scarring, glaucoma and coexisting choroidal detachment. The status of the lens is noted since the surgical technique may have to be modified in eyes with previous lens removal or in eyes with an intraocular lens implant. The results of the examination are discussed with the patient, including the rationale for surgery, realistic goals of surgery, the type ofanesthesia, risks of surgery, possible complications, duration of convalescence, possible need for reoperations, and possible functional limitations after surgery such as incomplete visual recoveryor strabismus. The possibility that the retina may be successfully reattached by the surgery (anatomic success) but may never regain useful vision (functional failure) should be discussed. Binocular patching of the eyes and/or bedrest are sometimes utilized preoperatively to limit the spread of the retinal detachment or to promote absorption of subretinal fluid prior to the retinal detachment repair. A presurgical medical examination is performed to evaluate any systemic illnesses which may impact on the method of anesthesia or surgery. 1563
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TIMING OF SURGERY Retinal tears may progress to retinal detachments within hours to days. Hence, when a retinal tear is found, treatment is usually performed the same day or within a few days depending on the surgeon's assessment of the risk of the retinal tear progressing to a rhegmatogenous retinal detachment. If a rhegmatogenous retinal detachment is present, the presence or absence of macular detachment is the major determinant of the urgency of repair of the detachment. If the macula is attached, the following guidelines may be used. 1) The retinal detachment repair is performed within a few days to a week if the detachment is in the periphery and does not have features which suggest rapid progression. 2) The retinal detachment repair should be done as soon as possible, preferably within 24 hours if the detachment is close to the macula. 3) The retinal detachment repair may be done within several hours of diagnosis by the retinal surgeon if the macula is imminently threatened by the detachment or if the detachment is secondary to a giant retinal tear (a retinal tear 90 degrees or greater in extent). If the macula is detached, the following guidelines may be used. 1) The retinal detachment repair is usually done within one to two days if the macula became detached a few days prior to presentation to the surgeon's office. Increased macular function may be regained if the recently detached macula is promptly reattached. 2) The retinal detachment repair may be performed electively within a week or two if the detachment is chronic and has already involved the macula. The timing of retinal reattachment surgery also depends on other features of the ophthalmic and medical examination which must be considered in addition to the status of the macula.
TECHNIQUE FOR RETINAL DETACHMENT REPAIR
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is generally advisable to have an anesthesiologist or anesthetist on standby for retinal detachment repairs performed using local anesthesia because the duration of surgery may be unpredictable, prolonged sedation may be needed, the patient's vital signs must be monitored and occasionally the local anesthesia may have to be converted to general anesthesia because of poor patient cooperation. The major disadvantages of local anesthesia are the risks of retrobulbar anesthetic injection, inadequate pain control and patient anxiety with the inability of some patients to cooperate for the duration of the surgery. General anesthesia has the advantage of immobility of the patient and complete pain control during surgery which is especially helpful for long procedures or reoperations. The major disadvantages of general anesthesia include prolonged recovery time and increased systemic risks. The surgeon is in the best position to discuss the optimal form of anesthesia with the patient after the history and examination have been completed, since the risks and benefits of local versus general anesthesia can be evaluated better at that time. PREPARATION OF THE EYE FOR RETINAL DETACHMENT REPAIR
The pupil must be dilated using one or more topical mydriatic medications such as tropicamide, phenylephrine, homatropine or cyclopentolate prior to retinal detachment repair. Some surgeons use preoperative topical antibiotics to decrease the normal bacterial flora on the external eye. The eyelashes may be trimmed preoperatively to decrease the risk oflashes contaminating the surgical field. The eyelids are cleansed in the operating room with topical antimicrobial solution on the eyelids and face surrounding the eye. The operative field is then covered with sterile drapes and the eyelids are kept open with a lid speculum. A lateral canthotomy may be needed in some eyes with tight eyelids or when better exposure of the posterior globe is needed. OPERATIVE PROCEDURE8 ,9,1O,1I ,12
ANESTHESIA
The decision whether to perform surgery for retinal detachment under local anesthesia or general anesthesia is determined by the surgeon and patient in consultation with a medical specialist when severe cardiovascular or cardiopulmonary disease is present. The surgeon must provide guidance about what type of anesthetic is most appropriate based on the estimated duration of the surgery, the patient's ability to cooperate with local anesthesia and the risk of general anesthesia in that patient. A primary, uncomplicated retinal detachment repair may require one to two hours. Reoperations or complicated retinal detachments may require as much as four to five hours. Some retinal surgeons perform a majority of their surgery under local anesthesia while other surgeons perform a majority of their surgery using general anesthesia. Local anesthesia has the advantage ofless systemic risk to the patient, decreased total operating room time, and more rapid postoperative recovery from the anesthetic. It 1564
A conjunctival peritomy is performed to expose the sclera and recti muscles. A bridle suture is placed around each of the four rectus muscles and the sclera is examined in each of the quadrants for abnormalities such as scleral staphyloma. The retina is examined by scleral depression to identify the topography of the retinal detachment and vitreoretinal interface. Any changes from the preoperative examination are noted. The retinal breaks are localized on the sclera and their location is accurately marked on the sclera with a tissue marker pen or diathermy. Each of the retinal breaks is surrounded by a type of thermal retinopexy such as cryopexy, diathermy or laser photocoagulation to create a chorioretinal adhesion between the retina and retinal pigment epithelium. Cryopexy or laser photocoagulation may be deferred until after drainage of subretinal fluid in cases where the retina is initially highly elevated above the retinal pigment epithelium. Diathermy may be used instead of cryopexy after dissection of the scleral bed if a scleral implant is to be used.
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The surgeon must then choose the size, shape and type of scleral buckle needed to adequately close all of the retinal breaks and relieve any areas of vitreoretinal traction. Scleral exoplants or implants are usually composed of one of two materials: I) " hard" (semi-flexible) solid silicone rubber or 2) "soft" (flexible) silicone rubber sponges. The silicone buckle material may be soaked in antibiotic solution before being placed around the eye to reduce the risk of infection. 13 If a scleral buckle exoplant is chosen , then the sutures are placed at appropriate locations in the sclera to anchor the scleral exoplant. If intrascleral buckling is chosen using a scleral buckle implant, then a lamellar dissection of the sclera is performed to create a pocket to hold the implant in position. Occasionally, extraocular muscles are temporarily disinserted to allow placement of the scleral buckle under an extraocular muscle. Diathermy may be used to create the chorioretinal adhesion instead of cryopexy when lamellar dissection of the scleral bed is performed in eyes treated with a scleral buckle implant. Many surgeons prefer scleral buckle exoplants since the use of exoplants avoids lamellar scleral dissection which increases the duration of surgery, exoplants are less likely to intrude into the eye and reoperations with revision of the buckle are less likely to cause scleral rupture. Some surgeons prefer intrascleral implants because they have the advantage of avoiding placement of anchoring scleral sutures which can perforate the globe. Scleral implants are also less likely to extrude through the conjunctiva to become exposed. Subretinal fluid may be drained depending on the location and height of the retinal detachment. Some surgeons drain subretinal fluid in most cases while other surgeons rarely drain subretinal fluid but may use other modalities such as intravitreal gas injections to tamponade the retinal breaks internally. The success of retinal reattachment is similar in drainage versus nondrainage procedures.!" In eyes where drainage of subretinal fluid is planned, the fundus is examined to identify a site with adequate subretinal fluid to allow safe drainage of subretinal fluid. Transillumination or placement of the drainage site near the horizontal recti may be used to try to avoid making the scleral drainage incision over any large choroidal vessels. Drainage of subretinal fluid is usually performed by making a radial incision through the sclera to expose the choroid. The choroid may be diathermized to minimize the risk of bleeding. A diathermy needle or a sharp suture needle is used to make a small hole in the exposed choroid. Gentle pressure ma y be applied to the globe to aid in drainage of subretinal fluid. Ophthalmoscopy is performed to determine whether all of the subretinal fluid has been drained or if complications such as subretinal bleeding or retinal incarceration have occurred at the drainage site. The drainage sclerotomy may then be closed with an absorbable suture to prevent any postoperative drainage of subretinal fluid or retinal incarceration, although some surgeons prefer to leave the drainage site open if there is residual subretinal fluid. Drainage of subretinal fluid helps to immediately reappose the retina to the scleral buckle by decreasing the height of the detachment and the volume of subretinal
fluid. Drainage also lowers the intraocular pressure and compensates for the intraocular volume displacement by the scleral buckle. The scleral exoplant or implant is then secured and tightened to create an indentation or "buckle" in the sclera. Temporary knots in the sutures around the scleral buckle exoplant may be used to allow adjustment of the buckle height after examining the eye. The intraocular pressure ma y increase as the scleral buckle is tightened due to intraocular volume displacement by the scleral buckle. The fundus is examined to verify that the central retinal artery is not occluded from a high intraocular pressure. The amount of residual subretinal fluid is noted to determine whether additional drainage of subretinal fluid is desirable. The adequacy of support of the retinal tears and relief of vitreoretinal traction by the scleral buckle is evaluated. The buckle is secured permanently if temporary knots were used to secure the scleral exoplant. If the intraocular pressure remains elevated, then paracentesis of aqueous humor from the anterior chamber or in rare instances, removal of vitreous from the vitreous cavity may be performed to normalize the intraocular pressure. Some patients are given intravenous medications such as acetazolamide preoperatively or intraoperatively to suppress aqueous production. Suppressants of aqueous production lower the intraocular pressure during surgery and minimize elevation of the intraocular pressure immediately after surgery. If the eye has a very low intraocular pressure after drainage of subretinal fluid and placement of the scleral buckle, then a balanced salt solution may be injected into the eye via the pars plana to normalize the intraocular pressure. Alternatively, an intraocular gas bubble injection may be desirable to tamponade retinal breaks internally if the breaks remain elevated over the scleral buckle. Air or expansile gases such as sulfur hexafluoride (SF 6), perfluoromethane (CF4), perfluoroethane (C2F6 ) , perfluoropropane (C3Fs), perfluoron-butane (C4F IO) or octofluorocyclobutane (C4F s) are injected through the pars plana if an intraocular gas bubble is needed.P:" Antibiotic solution may be irrigated around the eye followed by closure of Tenon's capsule and the conjunctiva with absorbable sutures. Subconjunctival antibiotics and/or steroids are usuall y given, followed by topical antibiotics, topical steroids and topical mydriatics. The eye is covered with a sterile patch and protective shield prior to leaving the operating room . Several portions of the procedure such as drainage of subretinal fluid and exposure of the sclera for placement of the buckle require an assistant to be performed safely. Thus, most retinal detachment repairs with a scleral buckle are performed by the surgeon with a surgical assistant.
INTRAOPERATIVE COMPLICATIONS There are a number of intraoperative complications which may compromise the surgical objectives of the retinal detachment repair, forcing the surgeon to alter the
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basic operative technique. Potential intraoperative complications include retrobulbar hemorrhage, scleral rupture, choroidal or retinal perforation, subretinal hemorrhage, vitreous hemorrhage, choroidal detachment, retinal incarceration and central retinal artery occlusion. Retrobulbar hemorrhage or perforation of the globe may occur with use of retrobulbar anesthetic injections when performing retinal reattachment under local anesthesia.!? Scleral rupture may occur during the initial exposure of the sclera, during examination of the retina with scleral depression or placement of the scleral buckle. Scleral rupture occurs most commonly in myopic eyes with scleral staphyloma or in eyes with previous retinal detachment surgery where there is extensive scarring of the conjunctiva and Tenon's capsule to the sclera with thinning of the sclera at the site of the previous scleral buckle. Scleral rupture can be a catastrophic complication with loss of intraocular contents. The rupture must be closed to reestablish the integrity of the globe and allow continuation of the surgery. Perforation of the choroid or retina may also occur during placement of scleral sutures for a scleral buckle exoplant or during lamellar scleral dissection for an implant. Scleral perforation is most common in eyes with thin sclera due to myopia, scleral staphyloma or previous retinal detachment repair. Scleral perforation by a suture is often self-sealing once the offending suture is removed, but perforation of the choroid may cause subretinal bleeding and/or vitreous hemorrhage. Subretinal hemorrhage from choroidal bleeding may impair adequate reattachment of the retina and impair visual recovery, especially if the subretinal hemorrhage moves to the macular region. Vitreous hemorrhage from scleral and/or retinal perforation may impair the view of the retina such that completion of the retinal detachment repair is difficult. Pars plana vitrectomy may be required to remove a severe vitreous hemorrhage, thus allowing continuation of surgery. Choroidal perforation by a suture usually does not have to be treated specifically. Retinal perforation must be treated by producing a chorioretinal adhesion with cryopexy or diathermy and may require revision of the scleral buckle to support the retinal perforation site. Hemorrhagic choroidal detachment may result from choroidal perforation during placement of scleral sutures or may occur spontaneously. Non-hemorrhagic serous choroidal detachments may occur preoperatively, intraoperatively or postoperatively. Hemorrhagic and serous choroidal detachments can prevent adequate settling of the retina against the buckle postoperatively, leading to persisting retinal detachment. Drainage of subretinal fluid may be associated with multiple complications. 18 Choroidal bleeding with drainage of subretinal fluid may occur despite diathermy to the vascular choroid prior to drainage of subretinal fluid. Retinal perforation may occur if the choroid is punctured over an area of shallow retinal detachment. Drainage may then be accompanied by loss of vitreous through the retinal break with incarceration of vitreous and retina into the drainage site. Retinal incarceration may complicate drainage if the subretinal fluid drains too rapidly, pulling 1566
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the retina into the drainage site. Increasing the height of the scleral buckle may increase the intraocular pressure due to displacement of intraocular volume by the scleral buckle in nondrainage procedures or in some drainage procedures where a broad scleral buckle in used.!? The intraocular pressure must not be allowed to remain very high at the completion of the surgical procedure or central retinal artery occlusion may occur with subsequent infarction of the inner retina and profound vision loss.
POSTOPERATIVE CARE The operated eye is usually treated with a topical antibiotic, topical steroid and topical mydriatic drops starting on the first postoperative day after retinal detachment repair. The eye may be covered with a patch for one or more days after surgery until the eye is comfortable. Ambulation is encouraged as soon as possible. The patient may be discharged from the hospital one to three days after the surgery, unless there are complications, depending on the duration and complexity of the surgery as well as the medical status of the patient. Some retinal detachment repairs requiring short operative procedures under local anesthesia may be performed as an outpatient procedure although many patients require an inpatient stay to monitor vital signs, administer intravenous fluids, control pain, treat nausea, vomiting and monitor the eye for early complications such as hemorrhage, infection, elevated intraocular pressure or redetachment of the retina." The operated eye is examined daily while the patient is hospitalized to monitor the response to the surgery and to detect any complications in the early postoperative period. The patient is examined as an outpatient with the frequency of visits determined by the status of the eye after retinal detachment repair. The surgeon who performs the retinal detachment repair is responsible for the preoperative evaluation and postoperative care. Preoperative examination by the surgeon determines the type of surgical procedure required to close the retinal breaks causing the retinal detachment. Postoperative care by the surgeon allows the surgeon to monitor the success of the retinal detachment repair and to detect any postoperative complications. The surgeon will usually reexamine the patient postoperatively two or more times in the first month after the retinal detachment repair. Once the surgeon is satisfied that the eye is stable, the patient may be returned to the referring physician for further ophthalmic care. Many retinal surgeons will reexamine the patient between six and twelve months after surgery to monitor for any late postoperative complications and to examine the fellow eye which is at increased risk for a retinal tear or detachment if the operated eye had a non-traumatic retinal detachment. If the patient is unable to return to the surgeon for postoperative care due to geographical or other extenuating circumstances, the surgeon may transfer care to another ophthalmologist who is qualified to monitor the response to the retinal detachment repair.
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EARLY POSTOPERATIVE COMPLICATIONS Retinal detachment repair has an overall success rate of 90% with one or more operations." Certain complications may lead to failure of the retinal detachment repair within the first few weeks after retinal reattachment (early postoperative complications), while other types of complications generally occur one or more months after surgery (late postoperative complications). It is much less common for an eye to develop complications more than six months postoperatively, although retinal redetachment, exposure or infection of the scleral buckle may occasionally occur years later. Early postoperative complications include persisting retinal detachment, buckle exposure, buckle infection, endophthalmitis, choroidal detachment, elevated intraocular pressure, glaucoma, conjunctival adhesions and anterior segment ischemia/ necrosis. PERSISTING RETINAL DETACHMENT
If the subretinal fluid does not resorb, additional procedures such as injection of an intraocular gas bubble or laser photocoagulation as an outpatient may need to be done. It may become apparent postoperatively that the buckle is not adequately supporting the retinal breaks. Inadequate closure of retinal breaks may be due to vitreous traction, persisting bullous detachment, improper buckle position or inadequate buckle height. Redetachment of the retina may be caused by the formation of new retinal breaks. These occur most frequently in the early postoperative period. New retinal breaks occur most commonly when an intraocular gas bubble has been injected into the eye.22 ,23,24 Reoperation with revision of the scleral buckle is required if the buckle is not adequately supporting all of the retinal breaks and the situation cannot be resolved by a less invasive procedure such as an intraocular gas injection or laser photocoagulation. BUCKLE EXPOSURE OR INFECTION
Some complications may be related to the use of a scleral buckle. Exposure of the scleral buckle may occur with or without signs or symptoms of an external buckle infection. An infection of the scleral buckle is treated by removing the scleral buckle, sutures and administering topical antibiotics. Oral or intravenous antibiotics may be needed to treat a buckle infection depending on the severity of the infection. 25 ,26,27,28,29,3o,3 1 Endophthalmitis may develop from spread of an external buckle infection into the eye or may develop from inadvertent inoculation of bacteria into the eye at the time of surgery: e.g., during drainage of subretinal fluid, paracentesis or intraocular gas bubble injection. Treatment of endophthalmitis requires intravenous antibiotics, intravitreal antibiotics and usually pars plana vitrectomy depending on the severity of the infection.
CHOROIDAL DETACHMENT
Choroidal detachment results from exudation of fluid within the choroid. Choroidal detachments generally resolve within one to two months after surgery. Oral steroid therapy may hasten resolution of the choroidal detachment in a small number of eyes. Surgical drainage of the choroidal detachment may occasionally be required if the choroidal detachment is so large that it involves the macula, comes in contact with large choroidal detachment extending from the opposite side of the globe or is persistent. ELEVATED INTRAOCULAR PRESSURE
The intraocular pressure may become elevated following retinal detachment repair. Intraocular pressure elevation is usually transient and can be treated with topical or systemic inhibitors of aqueous humor formation such as topical beta blockers, oral acetazolamide or oral methazolamide. Occasionally, angle closure glaucoma results from forward displacement of the iris after an encircling scleral buckle. Closure of the anterior chamber angle causing elevated intraocular pressure may be associated with choroidal detachment and will usually resolve with cycloplegics, aqueous suppressants and topical steroids. Surgical drainage of the choroidal detachment and reformation of the anterior chamber may be required if the eye does not respond to topical medications. Peripheral iridectomy may be needed to treat angle closure glaucoma if medical treatment fails. CONJUNCTIVAL ADHESIONS
An adhesion between the palpebral and bulbar conjunctiva (symblepharon) may lead to ocular motility problems and abnormalities ofthe lids. These conjunctival adhesions can be lysed with a glass rod in the office if detected early in the postoperative course. ANTERIOR SEGMENT ISCHEMIA/NECROSIS
Anterior segment ischemia and anterior segment necrosis are serious complications of retinal detachment surgery. Anterior segment necrosis results from impaired blood flow to the anterior segment and impaired venous return of blood from the anterior segment. Anterior segment necrosis is characterized by corneal edema and abnormal intraocular pressure. The intraocular pressure may initially become elevated but the eye eventually develops hypotony. It may lead to shrinkage of the eye (phthisis bulbi). Anterior segment necrosis is most frequent in elderly patients with broad or posteriorly located encircling scleral buckles or in eyes where more than two extraocular muscles have been disinserted and reattached during surgery. Patients with sickle cell retinopathy are also at increased risk for development of anterior segment necrosis after retinal detachment repair.F Anterior segment ischemia can be treated successfully in some eyes by intensive steroid therapy or surgically by loosening the encircling scleral buckle. 1567
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LATE POSTOPERATIVE COMPLICATIONS Some of the late postoperative complications are identical to early postoperative complications. These include persisting retinal detachment from inadequately supported retinal breaks or inadequate chorioretinal adhesion surrounding one or more breaks. Reoperation with revision ofthe scleral buckle is usually required ifthe retina fails to reattach within 1 month of surgery or as soon as the surgeon is convinced that the retina will not reattach. PERSISTING VITREORETINAL TRACfION AND PROLIFERATIVE VITREORETINOPATHY
Vitreoretinal traction may prevent closure of the retinal break and reapposition of the retina to the retinal pigment epithelium, leading to a recurrence of the retinal detachment. If the vitreoretinal traction is focal, then reoperation with revision of the scleral buckle or vitrectomy can be employed. Sometimes the retina initially attaches after surgery but redetaches several weeks to months later due to cellular proliferation and contraction on the surface of the retina and vitreous base. This cellular proliferation is called proliferative vitreoretinopathy. Mild forms cellular proliferation may be treated with revision of the scleral buckle. Moderate and severe forms of proliferative vitreoretinopathy are usually treated with revision of the scleral buckle combined with pars plana vitrectomy, dissection and removal of the epiretinal proliferation, thermal retinopexy and fluid-gas exchange. Some eyes with severe proliferative vitreoretinopathy require intraocular tamponade with intravitreal silicone oil. Proliferative vitreoretinopathy is the most common cause of failed retinal detachment repair." PERSISTING SUBRETINAL FLUID
Subretinal fluid may persist in the absence of identifiable open retinal breaks. Persisting subretinal fluid is usually monitored since it will eventually resorb if there are no remaining open retinal breaks. REFRACfIVE ERRORS
Refractive errors induced by changes in the shape of the eye may occur as a result of retinal detachment repair. These refractive changes include astigmatic errors as well as changes in spherical equivalent. The spectacle or contact lens prescription will need to be changed if there is a substantial change in refraction. 33 ,34,35,36 STRABISMUS
Ocular motility disturbances may follow retinal detachment repair with a scleral buckle. 37 ,38,39 Strabismus is most common when the scleral buckle must be placed under one of the extraocular muscles. The degree ofstrabismus often improves in the first six months following retinal detachment repair, but some strabismic deviations 1568
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are permanent and may require use of prisms or surgical correction.'? CYSTOID MACULAR EDEMA
Some postoperative complications compromise the function of the macula. Cystoid macular edema is the result of extracellular intraretinal fluid accumulation in the macula which may result in decreased vision. Cystoid macular edema is relatively common following retinal detachment repair and may account for vision loss in eyes whether or not the macula was detached preoperatively. Cystoid macular edema noted postoperatively may have been present, but undetected, preoperatively. Cystoid macular edema is present to at least some degree in about 9% to 25% ofphakic eyes and 29% to 64% of aphakic eyes after retinal detachment repair. 4 1,42,43 MACULAR EPIRETINAL MEMBRANE
Another source of decreased vision after retinal detachment repair with scleral buckle is a macular epiretinal membrane, due to formation ofscar tissue on the macula. Macular epiretinal membranes have also been referred to as premacular fibrosis, surface wrinkling retinopathy, internallimiting membrane contracture and macular preretinal membranes. Epiretinal membranes occur in about 8% of eyes after retinal detachment repair." Epiretinal membranes occur as a result of cellular proliferation on the surface of the macula and may represent a mild form of proliferative vitreoretinopathy. Epiretinal membranes localized over the macula usually do not cause recurrent rhegmatogenous retinal detachment. Epiretinal membranes may cause substantial distortion of the macula with vision loss from macular distortion or cystoid macular edema." Ifthe epiretinal membrane is thought to be the principle cause for decreased postoperative vision, then pars plana vitrectomy and epiretinal membrane dissection may improve vision." INFECTION
Infection of the scleral buckle may occur shortly after retinal detachment repair or many years later. 28 ,30 Scleral buckle infection requires removal of the scleral buckle whether the infection occurs as an early or late postoperative complication. SCLERAL BUCKLE EXPOSURE OR INTRUSION
Scleral buckle exposure without evidence of infection usually requires eventual removal of the scleral buckle since exposure ofthe buckle may lead to infection. Scleral buckles may occasionally intrude into the eye, although this has become less frequent with improvements in scleral buckling materials and techniques." CATARACf
Cataracts may develop or progress more rapidly in eyes after retinal detachment repair. Cataract extraction may
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REPAIR OF RHEGMATOGENOUS RDs
be required to restore vision and to allow continued examination of the retina. In general, cataract extraction is avoided for at least several months after retinal detachment repair to allow a maximal chorioretinal adhesion to form around the retinal break(s) before subjecting the eye to additional surgery. PHTHISIS BULBI
Phthisis bulbi with hypotony may follow retinal detachment repair leading to shrinkage of the globe and opacification of the cornea with vascularization. Phthisis may be the result of persisting retinal detachment, anterior segment ischemia, excessive postoperative inflammation with hypotony, choroidal detachment or may occur for no apparent reason. Most or all vision is lost in eyes that develop phthisis bulbi. Eyes must be monitored carefully after retinal detachment repair to detect and try to treat postoperative complications that can lead to irreversible damage to the eye.
THE RESULTS OF RETINAL DETACHMENT REPAIR The anatomic and visual success rates of retinal detachment repair have gradually improved over the past decades as a result of improved surgical techniques, improved materials and an improved understanding of the pathophysiology of retinal detachment. Anatomic success is usually defined as reattachment of the retina posterior to the scleral buckle. Anatomic success is an important measure of success since anatomic success usually confers long term stability to the retina and visual acuity. Functional success with retinal detachment repair is determined by the best corrected visual acuit y obtained six months or more after the retinal detachment repair. Some eyes have an anatomically successful retinal detachment repair but have functional failure due to very poor postoperative VISIOn.
ANATOMIC SUCCESS
With current techniques about 90% of retinal detachments can be successfully reattached with one or more operations.v":" The anatomic success rate however is dependent on the preoperative pathology causing the retinal detachment. Retinal detachments due to small atrophic holes, retinal dialyses and horseshoe tears have an excellent prognosis with a success rate ofover 95%.9,48,49 Retinal detachment repair in aphakic eyes without intraocular lenses has a success rate between 88% and 96%.9.50 Retinal detachment repair in eyes with anterior chamber intraocular lenses has a success rate of about 69% with one operation." The success rate increases to approximatcly 83% with one or more surgical procedures.P'
