Statistics from Altmetric.com
Excision of type 1 choroidal neovascular membranes (CNVM) in age related macular degeneration (AMD) have a poor visual outcome because of loss of retinal pigment epithelium (RPE).1 Simple replacement of the RPE may not work because the relation with Bruch’s membrane and choroidal complex is disturbed. Creating a free graft of these three layers detaches the choroid from its blood supply. Hence, restoration of these three layers to the subfoveal position while maintaining a connection to the adjacent choroidal blood supply is desirable.
A 74 year old woman presented with a 3 month history of a left central scotoma and visual acuity (VA) of counting fingers (CF). Clinical examination and fluorescein fundus angiography (FFA) confirmed a type 1 subfoveal CNVM. The fellow eye was 20/30 with scattered soft drusen. Pars plana vitrectomy (PPV) and excision of the CNVM were performed as described previously.2 Atrophic choroidal vessels underlying the CNVM were not removed. A retinotomy was formed temporal to the fovea and vertical scissors inserted into the subretinal space. The RPE, Bruch’s membrane, and choroid were incised en bloc in the area temporal to the site of the CNVM to create a graft on a pedicle. The graft was manipulated to a subfoveal position. The pedicle and graft were equally sized to maximally exploit the rich choroidal vasculature and maintain continuity to the choroidal circulation. We were unable to predetermine the position of choroidal vessels as indocyanine green angiography (ICG) was unavailable to us at the time of surgery. Surprisingly, little bleeding occurred and was easily controlled by increasing the infusion height. The patient required two subsequent operations for a rhegmatogenous retinal detachment with grade B proliferative vitreoretinopathy. The retina was flattened after inferior retinectomy and silicone oil insertion.
At review 4 years following initial surgery her vision was CF with a central scotoma on Goldmann field testing. The area of translocated RPE, Bruch’s membrane, and choroid was visible beneath the fovea with bare sclera demarcating its original site (fig 1A). At 4 years following surgery there was no recurrence of the CNVM on FFA (fig 1B) and ICG angiography demonstrated that the graft and pedicle were vascularised (fig 2).
Excision of type 1 CNVMs has a poor prognosis because of loss of RPE and atrophy of the choroid.2 Restoration of the normal anatomical relation between the retinal receptors and the underlying structures is essential for visual recovery. Retinal translocation with strabismic surgery for the movement of the retina to healthy RPE is prolonged and hazardous. Transplantation of homologous RPE cells alone to a subfoveal position has met with varied success.3 Aylward et al reported no visual improvement after transplantation of an autologous free graft, with fibrosis of the grafts at 10 months, perhaps because of loss of blood supply.4 Late revascularisation of some grafts has been reported at 1 year5
There was no visual improvement in our patient as she had a retinal detachment and additional procedures. We thought that the rich and redundant blood supply of the choroid allowed some freedom in the choice of graft harvest site. As proof of principle we have demonstrated that a choroidal/RPE graft with a pedicle is a feasible surgical technique, resulting in a sustained and vascularised graft. This technique is simpler than time consuming retinal translocation and does therefore merit further investigation.