糖尿病黄斑症に対して内境界膜除去は必要か

Rationale of removal of inner limiting membrane for diabetic maculopathy

（R2-7PM-5）　増殖糖尿病網膜症，虹彩ルベオーシス，硝子体出血，び漫性黄斑浮腫のある49歳男性の左眼に硝子体手術を行った。後部硝子体剥離を作製し，内境界膜は除去しなかった。び漫性黄斑浮腫は消失し，視力は手動弁から0.01に改善した。同様な網膜症のある右眼には手術を行わなかった。1年後に全身状態が悪化して死亡した。摘出した右眼（非手術眼）では，電子顕微鏡による検索で，内境界膜とミューラー細胞が浮腫状を呈し，硝子体側に肥厚した膜があった。左眼（手術眼）では，内境界膜の肥厚と多数の円形の空胞があり，ミューラー細胞に浮腫はなく，網膜内層の浮腫も右眼よりもはるかに軽度であった。内境界膜を切除しなかった左眼に網膜浮腫の改善があったことと，浮腫状に肥厚した内境界膜の切除が実現困難であることから，糖尿病黄斑症での内境界膜の除去は必ずしも必要でないと結論される。

We performed vitreous surgery on the left eye of a 49-year-old male with proliferative diabetic retinopathy, rubeosis iridis, vitreous hemorrhage and diffuse macular edema. During surgery, the posterior vitreous membrane was artificially detached. The inner limiting membrane (ILM) was left intact. Following surgery, diffuse macular edema disappeared and the visual acuity improved from hand motion to 0.01. The patient died one year later before surgery could be performed on his right eye which showed similar diabetic retinopathy. By electron microscopy, the removed right eye showed edematous Mueller cells and ILM. A thick membrane was present inner to retinal surface. The left eye showed thinkened and edematous ILM containing numerous vacuoles. The Mueller cells showed no edematous changes. Edema in the inner retinal layers was far less severe than in the right eye. These findings show that the retinal edema had improved in the left eye even after non-removal of ILM. Surgical removal of edematous and thickened ILM may also be not technically feasible. We conclude that removal of ILM may not be necessary in the surgical treatment of diabetic maculopathy.