Department of Ophthalmology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston, Mass. 02114, USA.
Ophthalmic Res. 2009;42(3):128-37. doi: 10.1159/000227278. Epub 2009 Jul 4.
To assess the feasibility of extraction of a chronically implanted subretinal electrode array.
Inactive, polyimide strips (10 mm x 1.5 mm x 15 microm) were surgically implanted into the subretinal space of 8 rabbits using a mostly ab externo approach. Pre- and postoperative clinical examinations, electroretinography and in some cases optical coherence tomography were performed to follow the course of the eyes. Two months after implantation, the polyimide strips were extracted from 5 eyes; 2 animals kept the implants and served as controls. All animals were then sacrificed and eyes enucleated for histological examination.
All 8 surgeries yielded successful placement of the arrays into the subretinal space. All 5 extraction surgeries were performed without obvious complications. Clinical examinations and electroretinography did not reveal any significant abnormalities. The histological examinations showed alterations from normal anatomy in all animals; the anatomical changes in the explanted animals were relatively mild and confined to the area of the surgery.
Successful extraction of electrode arrays from the subretinal space of rabbits can be reliably performed 2 months after implantation, which is beyond the time period when postoperative scarring would be most intense.
评估从视网膜下慢性植入的电极阵列中提取的可行性。
使用大多为外路的方法，将 10mm×1.5mm×15μm 的聚酰亚胺条带植入 8 只兔子的视网膜下间隙。在术前和术后进行临床检查、视网膜电图检查，在某些情况下还进行光学相干断层扫描，以观察眼睛的情况。在植入后 2 个月，从 5 只眼睛中提取聚酰亚胺条带；2 只动物保留植入物作为对照。然后，所有动物均被处死并眼球摘出进行组织学检查。
8 例手术均成功地将阵列植入视网膜下间隙。5 例提取手术均无明显并发症。临床检查和视网膜电图均未发现明显异常。组织学检查显示所有动物的解剖结构均发生改变；在已提取的动物中，解剖结构的改变相对较轻，仅限于手术区域。
在植入后 2 个月，可以可靠地从兔子的视网膜下空间中提取电极阵列，这超过了术后瘢痕形成最严重的时期。
