Limited macular translocation with scleral retraction suture

Abstract

Background/aims: Macular translocation with scleral imbrication is a new technique for treating subfoveal choroidal neovascular membranes (CNV). This procedure shortens the sclera but may result in a minimal decrease in the internal circumference of the globe and limits the amount of foveal displacement. The authors propose a new scleral retraction suture aimed at decreasing the internal circumference of the globe in an effort to increase foveal displacement.

Methods: Using a cadaver model, they compared the amount of scleral shortening using a standard scleral imbrication technique and a modified three suture scleral retraction technique. Sections of the globes were digitised and specialised software was used to estimate the amount of scleral shortening. Three patients with subfoveal choroidal neovascularisation underwent limited macular translocation using pars plana vitrectomy and macular detachment with the modified scleral suture technique. The main outcome measures were visual acuity, foveal displacement, and complications.

Results: In the cadaver model, the scleral retraction suture resulted in a flatter internal scleral fold compared to the standard suture technique and created approximately 890 microm of effective scleral shortening. In the patients who underwent macular translocation and laser photocoagulation of the CNV, visual acuity improved in two patients and worsened in one patient. The range of foveal displacement was 1400-2400 microm.

Conclusion: The foveal displacements achieved in this limited study compared to median displacement previously published using standard suture techniques demonstrates that the scleral retraction suture technique may be a useful adjunct to limited macular translocation. The advantage of this type of suture in conjunction with translocation may depend on the effective scleral shortening offered by this retraction suture.

Figure 1

(A) Standard imbrication: three 5-0 nylon circumferential mattress sutures in the superotemporal quadrant 9 mm and 15 mm from the surgical limbus. (B) Modified imbrication: three 5-0 nylon circumferential mattress sutures were placed in the superotemporal quadrant at 10 mm, 12.5 mm, and 15.0 mm from the surgical limbus. Medical illustration created by David Schumick, BS, copyright Cleveland Clinic Foundation Art Department.

Figure 2

Cadaver globe cross sections demonstrating (A) single scleral infolding with standard scleral imbrication suture and (B) double scleral infolding with modified scleral imbrication suture for LMT. The solid line represents internal circumference of the fold before suturing, the broken line represents internal circumference of the fold after suturing.

Figure 3

Drawing (A) and intraoperative photograph (B) of modified scleral imbrication suture for LMT before tightening. The sutures are placed before placement of the infusion cannula. Medical illustration created by David Schumick, BS, copyright Cleveland Clinic Foundation Art Department.

Figure 4

Drawing (A) and intraoperative photograph (B) of modified scleral imbrication suture for LMT after tightening. The sutures also create some radial imbrication, which may help in the translocation of the retina, creating shortening of the sclera circumferentially and radially. Medical illustration created by David Schumick, BS, copyright Cleveland Clinic Foundation Art Department.

Figure 5

Case 1. (A) Preoperative fluorescein angiogram of the right eye demonstrates subfoveal CNV with blood. (B) Postoperative fluorescein angiogram of the right eye shows extrafoveal CNV before laser photocoagulation with translocation of 1400 μm. The superior edge of the CNV was used to measure postoperative translocation

Figure 6

Case 2. (A) Preoperative fluorescein angiogram right eye demonstrates subfoveal CNV with blood. (B) Postoperative fluorescein angiogram right eye shows extrafoveal CNV before laser photocoagulation with translocation of 2300 μm. The subfoveal CNV was hard to visualise because of the blood. A chorioretinal scar nasal to the fovea was used to measure the translocation, which was found to be 1600 μm.

Figure 7

Case 3. (A) Preoperative fluorescein angiogram left eye demonstrates subfoveal CNV. (B) Postoperative fluorescein angiogram left eye shows barely juxtafoveal CNV despite translocation of 2400 μm.