E-Book, Englisch, 368 Seiten, ePub
Temporary Tamponades with Balloon and Gases without Drainage, Buckling versus Gases versus Vitrectomy, Reoperation, Case Presentations
E-Book, Englisch, 368 Seiten, ePub
ISBN: 978-3-13-257872-2
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Ophthalmologists, fellows in retinal and vitreous surgery, students and residents will find this information-packed manual essential for diagnosing and repairing retinal detachments. Reserve your copy today!
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Weitere Infos & Material
9 Temporary Balloon Buckle without Drainage: Minimal Extraocular Surgery for Retinal Detachments with 1 Break or Breaks within 1 Clock Hour
10 Temporary Gas Tamponades without Drainage: Minimal Intraocular Surgery for Retinal Detachments
11 Balloon Buckle versus Pneumatic Retinopexy for Uncomplicated Retinal Detachments
12 Limits of External Buckling in Treating Complicated Retinal Detachments
13 Pneumatic Retinopexy versus Vitrectomy as Primary Procedure for Retinal Detachments
14 Reoperation of Retinal Detachments without Drainage: Minimal Extraocular Surgery as Rational Approach
10 Temporary Gas Tamponades without Drainage: Minimal Intraocular Surgery for Retinal Detachments
10.1 History
The use of an intraocular gas bubble in retinal detachment surgery was first described by Ohm in 1911 [1]. At that time, however, the importance of the retinal hole in relation to a retinal detachment was not yet known. Ohm injected air into the vitreous via the drainage site (7 mm from the limbus). Why did Ohm inject air into the vitreous? To compensate for the loss of intraocular volume after drainage and To push the retina back into place. – It was a good idea. He applied the method in 2 patients, and the retina reattached. Yet the gas technique did not gain importance. In 1938, Rosengren [2] re-introduced the use of an intraocular air bubble for the treatment of a retinal detachment. What did Rosengren do differently? He used the intraocular air bubble To tamponade the retinal hole after drainage (Fig. 10.1). Fig. 10.1 The use of an intraocular air bubble to treat a retinal detachment by tamponading the retinal hole, first performed by Rosengren in 1938 (Figure from [2]). In contrast to Ohm, Rosengren had the advantage that Gonin [3] had since pointed out that the retinal hole is the cause of retinal detachment. Rosengren integrated this concept into his gas operation. That a gas bubble would not go through a retinal break was an original concept. Today, this concept is obvious to all those, who are knowledgeable about the surface tension of a gas bubble. Now a question you might raise: Did the Rosengren technique improve the rate of reattachment? Yes: – It improved by a further 10% the results of retinal detachment surgery, which up to that time consisted only of diathermy around the break and drainage. – The rate of reattachment rose to 77%. Rosengren's operation restored the intraocular volume with gas, flattened the retina with gas, and tamponaded the diathermized break. However, there was a drawback; the gas did not tamponade the break long enough. Why? – You might recall that air has a half-life of 1½ to 3 days (this is dependent upon how old you are and whether you are a high myope). – The tamponade with air did not last long enough in some eyes for a retinal adhesion to develop sufficient strength to secure the retinal break. – The time required to develop a secure retinal adhesion is at least 7 days. You might remember that after 1 week the retinal adhesion is strong enough to secure a retinal break, e.g., when a temporary balloon buckle is removed after 1 week (see Chapter 9.3, pp. 5–8). The maximum of a retinal adhesion after thermal coagulation is reached at 12 days (see Part 1, Chapter 7.2, pp. 96–109). Bearing these facts in mind, Rosengren's final results were as follows: – A certain number of detachments pulled apart on the 3rd or 4th day when the air tamponade had disappeared. However, the information available today about the time it takes for a retinal adhesion to develop sufficient strength was not available in 1938. This information did not become available until more than 30 years later, after extensive animal experiments had been performed [4,5]. Redetachment after the Rosengren procedure called for a better procedure. Retinal surgeons did not give up and the search for a better method continued. In the early 50’s various scleral buckling procedures were developed that yielded better results than the intraocular gas tamponade—though the air injection represented a significant conceptual advance. But the idea for an external tamponade of the break was first realized by Custodis [6] in 1953: He reduced extensive buckling then in practice to a buckle limited to the area of the break. In addition, he eliminated drainage of subretinal fluid. This new concept was made feasible by the use of elastic plombages. However, there were complications that jeopardized the acceptance of this procedure. Full thickness scleral diathermy facilitated scleral abscess in a number of patients and the explant Polyviol, made of gum Arabic, Congo red, and polyvinyl alcohol, was irritative. In 1963 Lincoff modified this operation [7,8] to eliminate the complications induced by the explant and diathermy: The cryo-surgical detachment operation was developed (see Part 1, Chapter 8.1, pp. 126–127). The operation was further refined during the 1970’s: The so-called minimal extraocular surgery for retinal detachment (Kreissig [9]) provided optimal results with a reattachment rate of substantially above 90%. Any good, new treatment will, however, either have unexpected complications or can be replaced by something better, e.g., for special indications. There was indeed a small group of detachments (about 7%) which proved unresponsive to minimal extraocular surgery, i.e., to segmental buckling without drainage. For which retinal detachments might external buckling have reached its limits? Which detachments will cross your mind? – Giant tears – Tears at the posterior pole – Multiple tears close together, but at different latitude. Having perceived the limits of scleral buckling, in 1965 Lincoff started animal experiments with various gases in search of a gas that would persist in the eye for a longer time than air. At that time the expansion potential of a gas (which would provide conditions for a nondrainage procedure with a gas) was not yet an issue. The longevity of an intraocular gas bubble depends largely upon its solubility. Sulfur hexafluoride (SF6) proved to be the best of the gases initially tested. Therefore, in 1967 Lincoff re-introduced the gas technique, limited to detachments not suitable for scleral buckling [10, 11]. He had replaced air by SF6 which stays twice as long in the eye. With this modified gas technique the problem of the Rosengren technique—a tamponade of too short duration—was eliminated. The injection of SF6 was, however, preceded by drainage of subretinal fluid, but it could provide a tamponade of sufficient intraocular duration for a retinal adhesion to develop. It was this which represented the progress. Additional reports about the clinical use of SF6 followed from: Norton [12], McLean and Norton [13], Abrahms et al [14], Fineberg et al [15], Laqua and Wessing [16], Kreissig [17], Kroll et al [18], Hausmann [19], etc. 10.2 Sulfur Hexafluoride (SF6)
10.2.1 History Sulfur hexafluoride or SF6 (Fig. 10.2) had been used in medicine for pneumothorax procedures. That was one of the reasons why Lincoff assumed it would not be toxic and might be suitable for the eye [10,11]. First of all let us recapitulate: Why was SF6 preferred to air? Because it remained twice as long as air in the vitreous. Why did SF6 remain in the eye longer? SF 6 is an inert gas that is relatively insoluble in the watery vitreous and therefore stays in the eye for a longer period. SF6 is colorless and odorless. It doubles its volume over a period of 24 to 48 hours. Fig. 10.2 The chemical structure of SF6, the first expanding gas, that was used in detachment surgery. Why does the increase in volume occur? SF6 expands because blood gases, i. e., nitrogen, oxygen, and carbon dioxide, diffuse into the intraocular gas bubble. At equilibrium the volume of the SF6 bubble has increased 1.9 times. It takes about 48 hours to reach the peak volume. The disappearance or absorption time of SF6 is twice as long as that of air. It takes 6 days for the bubble to diminish to half volume and 3 to 4 weeks for the last small gas bubble to disappear. However, for clinical use only the so-called half-life of a gas bubble, representing the time of a therapeutic gas volume, is of clinical interest (see Chapter 10.3, pp. 121–148). What about intraocular complications, since SF6 will be in the vitreous longer? I assume you are recalling the previous statement: Every new treatment will eventually present some complications or limitations. A temporary increase in intraocular pressure can occur. However, if the eye has a normal outflow and care is taken in the postoperative positioning of the patient's head (not to occlude the chamber angle by the gas...
