| ◄▬ | 2002 Oshitari ea | ▬► |
Oshitari ea, Long-term complications ofhydrogel buckles, Retina 2003;23:257-61
Oshitari e.a. beschrijven in een artikel van april 2003 hun onderzoek van 31 patiënten, bij wie tussen april 1998 en april 2001 Miragel plombes zijn verwijderd. De plombes waren tussen februari 1988 en oktober 1995 toegepast.
Abstract
Purpose: To investigate long-term complications of hydrogel buckles used in scleral buckling surgery for retinal detachment.
Methods: Clinical records of 31 patients who underwent scleral buckle removal between April 1998 and April 2001 were reviewed. Removed buckles were examined by scanning electron microscopy (SEM).
Results: Nineteen patients were men and 12 were women, with a mean age of 43 years. Initial scleral buckling surgery using hydrogel buckles had been performed between February 1988 and October 1995. Patients presented at a mean of 8.5 years postoperatively with complaints of symptoms such as foreign body sensation and diplopia, prompting buckle removal. Buckles from 28 eyes, left in place for 5.8 years or more, were discolored, friable, and swollen. Buckles from three eyes, left in place for 5.5 years or less, appeared grossly unaltered. One eye with buckle swelling associated with a large retinal cyst underwent buckle removal and vitrectomy. SEM of deteriorated buckles showed distortion of micropores when compared to grossly unal tered buckles and unused controls.
Conclusions: Severe deterioration of hydrogel buckles may occur when they are left in place for 5 years or longer and may cause adverse symptoms and rarely intraocular complications. This deterioration is associated with changes in the microstructural architecture of the hydrogel material.
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The MAI buckle, also known as the Refojo implant, is a synthetic hydrophilic scleral buckling material introduced in the 1970s. MAI is made of polymethyl acrylate-c02-hydroxyethyl acrylate cross-linked with ethylene diacrylate with 15% water, and it is the precursor of the present-day MIRAgel buckle (MIRA, Waltham, MA), which has the same basic chemical composition. Due to its softness and elasticity, the MIRAgel buckle was touted as being easy to handle and useful in creating a smooth scleral indentation. 1,2
We utilized MIRAgel in explant scleral buckling surgery from 1987 until 1996, when its distribution was voluntarily stopped by the manufacturer. However, complications have recently been reported in patients who received MIRAgel buckles that appear to be related to swelling properties of the hydrophilic material. 3 Over a 3year period, we removed MIRAgel buckles from 31 eyes of 31 patients who developed various symptoms, such as foreign body sensation and diplopia, and report our findings here.
Discussion
Several features of hydrogel material have been touted as being beneficial for use in scleral buckling surgery. Softness and elasticity were said to protect against scleral erosion. 2,4 A relative lack of "dead space" and the ability to absorb and then gradually release antibiotics were also believed to make this buckle less prone to infection. 4,5 However, before the halt in its distribution in 1996, we had been utilizing MIRAgel buckles mainly for their ease in handling and their ability to create a smooth scleral indentation.
De auteurs merken op dat - evenals andere plombes - hydrogel plombes makkelijk verwijderd kunnen worden, ‘simply pulled out’, als de structuur ervan nog niet is veranderd. Maar hydrogel plombes die meer dan vijfenhalf jaar tevoren waren toegepast, bleken te zwellen met extrusie of intrusie van de plombe. Deze plombes bleken na verwijdering doorzichtig en extreem bros te zijn geworden. De verwijdering ervan geschiedde met veel moeite stukje bij beetje.
Buckle extrusion is not an uncommonly encountered postoperative complication of scleral buckling surgery, especially after explant procedures. Removal of the buckle in these cases is usually relatively easy, since the mattress sutures in these eyes are often loose or detached from the sclera such that the buckles can simply be pulled out. Buckles that have eroded inward (buckle intrusion) can also be removed fairly easily, although cutting of scleral mattress sutures may be required. Hydrogel buckles used as explants can also be removed in a similarly easy manner, if they are removed before structural alterations. However, as we observed in 28 eyes, hydrogel buckles left in place for over 5.5 years resulted in buckle swelling, with associated buckle extrusion or intrusion. Removed MIRAgel buckles from these eyes were noted to have become translucent, gellike, and extremely friable, in comparison to unused MlRAgel buckles which are transparent, more solid, and elastic. In fact, we encountered much difficulty during attempted removal of the MIRAgel buckles. In most cases, the buckles had already become fragmented or disintegrated immediately upon light traction with forceps. Removal was often performed in a piecemeal fashion, and a muscle hook was commonly used to fish out buckle debris from the subconjunctival or sub-Tenon's space. Swollen buckles also inhibited globe rotation intraoperatively and made it difficult to gain access to remaining buckle fragments. A granulomatous reaction was observed surrounding the buckle material in some cases.
De Miragel degeneratie doet de plombes zwellen tot wel 185% met extrusie of intrusie als gevolg. Naar de mening van de auteurs treedt deze degeneratie al op zonder dat grote veranderingen te zien zijn.
Deteriorated MlRAgel has the tendency to absorb a great volume of water and therefore to increase in size. 1 Indeed, in our study, the calculated cross-sectional area of buckles from group A that were visibly altered had increased by an average of 185%. We believe this phenomenon to be related to the microstructural changes we observed by SEM. Swelling of the MlRAgel buckle within the confines of sub-Tenon 's space results in tortuosity of the buckle, with subsequent buckle dislocation and extrusion or intrusion. It has been reported that hydrolytic degeneration occurs with hydrogel material and that this process may occur even without physically evident alterations in the buckle. 6 Therefore, even in the absence of gross alterations in appearance of the buckles in group B, we believe that the process of degeneration had already begun, leading to various symptoms in the patients.
De auteurs signaleren het toenemend aantal gevallen met complicaties.
Hwang and Lim reported the first case of this complication 10 years after commercial use of the MIRAgel buckle had begun. 7 Roldan and colleagues also reported the long-term complications of MIRAgel when used as an episcleral buckling element. 3 In the Roldan study, 206 cases were followed for more than 7 years. Of these, five patients eventually underwent buckle removal for granulomatous reaction or chronic infecrion, but no patients developed buckle extrusion or intraocular erosion. Marin and colleagues reported seven cases with complications that developed 7 to 11 years after scleral buckling surgery using MAI hydrogel, the precursor of MlRAgel, as an intrascleral implant. 6 These complications ranged from a visible but nontender subconjunctival bulge to intraocular erosion to frank buckle extrusion. The implants were noted to be swollen, altered, translucent, gellike, and friable. Chemical changes of the polymer and hydrophilic degeneration of the material were confirmed spectrographically. Interestingly, Marin and colleagues stated that, in contrast to patients with MAI hydrogel buckles, complications were rarely observed in patients with MlRAgel buckles. 6
De indruk van de auteurs is dat de symptomen die patiënten ontwikkelen met hydrogel plombes veel ernstiger zijn dan die van patiënten met silicone plombes. Een van de patiënten in hun studie ondervond een duidelijk verlies van gezichtsvermogen door sclerale erosie, intrusie van de plombe en vorming van retinale cysten. Hoewel een dergelijke ernstige gezichtsbedreigende complicatie tot nu toe ongebruikelijk is, vermoeden de auteurs dat dit nog maar het begin is van alle mogelijke complicaties die verbonden zijn aan hydrogel plombes.
The current report represents the largest series of long-term complications of hydrogel buckles to date in the literature. Since we used this material in numerous scleral buckling cases, the number of patients returning to us with various complaints is still increasing. It is our impression that the symptoms patients develop with hydrogel buckles are much more severe than those of patients with silicone sponge or rubber buckles. In fact, one of the patients in our study experienced marked visual loss due to scleral erosion, buckle intrusion, and retinal cyst formation. Although such a severe vision-threatening complication is unusual to date, we have only begun to witness all the possible complications associated with hydrogel buckles. Recently, several Japanese vitreoretinal specialists have noted various complications in patients who received MIRAgel buckles (unpublished data, Drs. Takeshi Hoshino and Miyo Matsumura), and the Japanese Ophthalmologic Society has decided to make an official announcement regarding the seriousness of these complications.
Kortom, chirurgen dienen zich bewust te zijn van de complicaties en patiënten dienen regelmatig onderzocht te worden en gewaarschuwd voor mogelijke problemen. Ingeval van zwelling, extrusie of sclerale erosie en intrusie dient de plombe te worden verwijderd.
In summary, the long' term complications of hydrogel buckles may be quite severe with potential visual loss. Surgeons must be aware of these possible complications in patients who have received hydrogel buckles during scleral buckling procedures, and these patients should undergo periodic examination and be warned of the possibility of problems. When symptomatic buckle swelling or buckle extrusion occurs or if scleral erosion and buckle intrusion are identified, the hydrogel buckle material should be removed.
| ◄▬ | 2002 Oshitari ea | ▬► |