The Drainage of Subretinal Fluid: a Randomized Controlled Clinical Trial

THE DRAINAGE OF SUBRETINAL FLUID: A RANDOMIZED CONTROLLED CLINICAL TRIAL BY George F. Hilton, MD INTRODUCTION AMONG THE MANY CONTROVERSIES IN RETINAL DETACHMENT SURGERY, NONE HAS been more persistent than the unresolved question of drainage versus nondrainage. The controversy has persisted for over 20 years, and more than 60 papers have been written on the subject; however, to date there have been no controlled studies. The ongoing interest in this problem is illustrated by a recent Jules Gonin Club symposium on the drainage of subretinal fluid. After numer- ous papers on the subject the final summary acknowledged: "We are still challenged by the question: To drain or not to drain.'"1 The interest in this question is enhanced by the fact that most retinal surgeons regard the procedure ofsubretinal fluid drainage as a potentially hazardous step. Martin2 has defined it as "the most dangerous part of a retinal detachment operation." Ferguson3 referred to it as "the most crucial point" in the operation, and Norton4 observed that "fluid drainage is the one aspect ofthe surgical procedure over which the surgeon has the least control and although complications are unusual, they can be disas- trous." Not all authors are equally impressed with the potential complications ofdrainage. Chawla5 regarded this surgical step as "only one danger among equals," and Schepens6 wrote that "the rate of complications from correctly performed perforation for the release of subretinal fluid is less than 1%." This question was recently brought into focus by a pair of papers representing the two major schools of thought on the issue. Schepens,6 a major spokesman for the drainage school, stated that all retinal detachments should be managed with fluid drainage "except a few selected cases." Lincoff,7 a major spokesman for the nondrainage school, contend- ed that nearly nine out of ten detachments could be adequately repaired without surgical drainage of subretinal fluid. TR. AM. OPHTH. Soc. vol. LXXIX, 1981 518 Hilton The present study was undertaken with the hypothesis that equally good results, both anatomic and visual, could be obtained with either technique. HISTORICAL REVIEW The question ofsubretinal fluid drainage can best be appreciated against a background of the historical development of the entire field of retinal detachment surgery. The evolution of this operation is one of the most remarkable chapters in the history of ophthalmology. Gonin's operation for the repair of the detached retina ranks with Daviel's cataract extrac- tion and von Graefe's iridectomy for acute glaucoma as one of three great surgical treatments for blindness. The entity of retinal detachment was first recognized by Saint-Yves (1722)8 who reported the gross pathologic examination of an eye with this condition. The first clinical description did not appear until a report by Beer (1817).9 Apparently this was a very bullous detachment immediately behind the crystalline lens as he was able to make his observation without the benefit of an ophthalmoscope. With the invention of the ophthalmoscope by Helmholtz (1851), 10 a rapid succession of ophthalmoscopic ob- servations of detachment followed. Shortly after, Coccius (1853)" reported the ophthalmoscopic detection of breaks in the retina. von Graefe (1854)12 theorized that retinal detachment was due to a serous effusion from the choroid into the subretinal space. When he observed a retinal break, he assumed that it was secondary and repre- sented an attempt by the eye to cure itself. He supposed that with the development of such a break, the subretinal fluid could pass from the subretinal space into the vitreous cavity resulting in retinal reattachment. With this conviction in mind, he treated detachments with deliberate incision of the retina. Predictably his therapeutic approach was short- lived. Taking a point of view opposite to von Graefe's, de Wecker (1870)13 proposed that the retinal break was the cause ofthe detachment, with the passing of fluid vitreous through the break into the subretinal space. Unfortunately this correct observation was not generally accepted at that time. Leber (1882)14 reported the observation ofretinal breaks in 14 out of27 detachments, and he implicated vitreous traction in the pathogenesis of retinal tears. This accurate observation, however, was later repudiated by Leber. Subretinal Fluid 519 Gonin's15 operation involved the "searing" of the sclera, choroid, and retina at the retinal break site with a red hot probe, a procedure referred to as "ignipuncture." He reported his results initially to the French Ophthalmological Society in 1923 and the Heidelberg Congress in 1925. The great potential ofthese initial reports was generally overlooked by his colleagues. 16 Later, general interest was aroused by his paper presented before the International Congress of Ophthalmology in Amsterdam in 1929 wherein he reported surgical cure of 20 out of 30 cases of recent retinal detachment. However, in detachments of greater than three months duration, he reported a cure in only 15 out of 35. To Gonin goes the credit not only for developing his operation but for promoting and disseminating the new gospel. He did this with 34 papers, published in Belgian, German, English, American, Swiss and French journals. In each he emphasized the essential role of the retinal break and the necessity of closing all breaks with ignipuncture, a process which involved the drainage of subretinal fluid. What had previously been a uniform cause of blindness responded to Gonin's operation in about 60% ofcases. In 1934, he published his classic text "Retinal Detachment."'17 To Weve (1932)18 goes the credit for developing the use ofdiathermy, a marked improvement over the red hot searing technique of Gonin. Lindner (1933)19 introduced the technique of full thickness scleral resection and continued to utilize fluid drainage. Jess (1937)2° gave us the first description of scleral buckling but his brief mention was not followed up and the ophthalmic world had to wait almost two decades for the full development of scleral buckling. Rosengren (1938)21 added the valuable technique of intravitreal air injection for the closure of retinal breaks and this is still used in con- junction with the drainage of subretinal fluid. Schepens (1947)22,23 modified and developed the binocular indirect ophthalmoscope, initially described by Girard-Teulon in 1861. Schepens' instrument is now widely used and this important step forward was further augmented by the supplemental use of scleral depression, a technique originally introduced by Trantas (1926).24 With this technique the periphery of the retina could be brought more clearly into view, and of even greater importance, peripheral lesions could be viewed in dynamic profile as they were gently massaged by the scleral depressor. Both the indirect ophthalmoscope and the scleral depressor are widely used in selecting the site for subretinal fluid drainage. Shapland (1951)25 supplanted the full thickness scleral resection of Lindner with lamellar scleral resection in which only a partial thickness 520 Hilton band of sclera was removed. With the surgical closure of this wound, a moderate scleral buckling was achieved by the infolding of the partially thinned sclera and choroid. He also utilized perforation for the drainage of subretinal fluid. It is to Custodis (1952-1956)26-28 that we are indebted for the re- introduction and development of scleral buckling. He used a polyviol plomb which was sutured to the surface of the globe and thereby created a prominent segmental scleral buckle. Moreover he made the remarkable contribution of demonstrating that many retinal detachments may be cured without the drainage of subretinal fluid. He noted that retinal breaks do not necessarily have to be closed at the time of surgery and that they will usually close during the postoperative period if the buckle has been properly placed. The manner by which the buckle promotes the absorption of subretinal fluid is still not fully understood. The segmental scleral buckle of Custodis was extended and amplified by the development of an encircling scleral buckle by Schepens (1957). 29 He used a polyethylene tube which encircled the eye. Unfortunately this rather rigid encirclement led to the late complication of erosion of the sclera, choroid, and retina in some eyes. Therefore, it was replaced by a softer material, silicone rubber. The technique of subretinal fluid drainage was summarized by Schwartz (1959).30 He identified the two most critical points in retinal detachment surgery as the localization of the retinal breaks and the drainage of subretinal fluid. He described two techniques: perforating Pischel pins, and the Schepens method ofsclerotomy followed by perforation of the choroid with either an electrode or a punctum dilator. Three years later Ferguson3 published a very comprehensive review of the subject of fluid drainage and emphasized the two step technique of scle- rotomy followed by perforation of the exposed choroid. The drainage versus nondrainage controversy crystallized when Cus- todis visited the United States in 1960.3' He presented his results with the nondrainage method to a large symposium of retinal surgeons who were greatly interested in this unusual paper. Shortly thereafter, Lincoff visited the clinic of Custodis, returned to America with the zeal of a new convert, and published a series of papers popularizing the Custodis technique. 123' Lincoff and associates disseminated the nondrainage technique, but modified the Custodis procedure by replacing diathermy with cryotherapy and by replacing the polyviol sponge with silicone sponge. They reported satisfactory results in many types ofdetachments including those which were long standing, those with large breaks, posterior breaks, or inferior dialyses, as well as aphakic detachments. Subretinal Fluid 521 Their enthusiasm notwithstanding, the Lincoff group clearly specified that drainage was required in certain selected cases.40 While they were able to repair detachments in 87% of a large series with the nondrainage method, they encouraged the use of drainage in certain cases.

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