Graefe's archive for clinical and experimental ophthalmology-instant glue for retinal detachment surgery?

Abstract

Retinal tears were first observed in 1853, soon after the advent of the ophthalmoscope [1]. However, it took half a century before their role in the causation of rhegmatogenous retinal detachment was recognized, based on the seminal work by Jules Gonin from 1904 to 1931 [1]. Using a hot metal probe passing through a scleral incision, Gonin developed the first successful technique for retinal detachment repair by inducing thermal injury to the retina, retinal pigment epithelium (RPE), and choroid adjacent to retinal tears. Subsequent wound healing formed a watertight barrier between subretinal space and vitreous cavity. To date, thermal injury remains the basis of treatments for all retinal tears in retinal detachment surgery, ranging from Gonin’s hot metal probe to penetrating diathermy, and now contemporary cryoor laser retinopexy. It relies on wound healing to establish sufficiently tight chorioretinal fusion to seal off access of the subretinal space via retinal breaks. This process takes time. Additionally, both the retina and RPE or choroid must be held in apposition, either by indentation of the scleral wall (scleral buckling) or internal tamponade by gas or silicone oil. Chorioretinal adhesion caused by cryoor laser retinopexy has been reported to take between 2 and 4 weeks to reach maximum strength of adhesion [2, 3]. Nevertheless, laser photocoagulation may achieve a more rapid, albeit limited, enhancement of chorioretinal adhesion (within 1 to 3 days), whereas cryotherapy tends to invariably weaken adhesion for up to 1 week before it strengthens adhesion [3]. It has been postulated that the more acutely increased adhesion from laser retinopexy could be related to the development of a proteinaceous coagulum, and the initial reduced adhesion from cryo-retinopexy could be due to chorioretinal edema. Regardless, both techniques rely chiefly on delayed wound healing and scar formation over a matter of weeks to achieve the degree of chorioretinal adhesion that can be considered an adequate barrier to prevent re-detachment of the retina. In this issue, Umanets and colleagues have examined the potential use of high-frequency electric welding (HFEW) as a new retinopexy technique for retinal detachment surgery [4]. In this experimental study, live rabbit eyes with flat retina were randomly assigned to receive standard laser retinopexy, HFEW retinopexy with two different voltage settings, or no intervention (controls). Enucleation was then performed and a full-thickness fragment of eye-wall tissue containing the area of retinopexy was isolated. Using a customized machine, the tensile strength of the chorioretinal adhesion was measured at various time points. The main finding was that HFEW retinopexy generated significantly firmer, and, more importantly, almost immediate (1 h or less) chorioretinal adhesion than that of laser retinopexy. The results of this study raised several important issues. Previous investigators have attempted to exploit instant adhesion during retinal surgery. Vicente Martinez-Castillo, for example, performed protracted vitrectomy shaving tightly the vitreous base and draining meticulously the last bit of subretinal fluid (by using an air bubble over perfluorocarbon liquid) [5]. Others have tried and failed with this technique. Perhaps there is a steep learning curve, but for whatever reason, the technique is not widely adopted, and there have been few publications to corroborate and repeat the excellent results published 7 years ago. Nonetheless, as a proof of principle, the publication has been highly influential and is N. Cheung :D. Wong (*) The Eye Institute, Department of Ophthalmology, University of Hong Kong, Pokfulam, Hong Kong, China e-mail: shdwong@hku.hk