Artikel
Results of the preoperative planning procedure in subretinal prosthesis implantation
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Autoren
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Akos Kusnyerik
- Semmelweis University, Department of Ophthalmology, Hungarian Bionic Vision Center, Budapest, Hungary
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U. Greppmaier
- Retina Implant AG, Reutlingen, Germany
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R. Wilke
- University of Tuebingen, Centre for Ophthalmology, Germany
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K. U. Bartz-Schmidt
- University of Tuebingen, Centre for Ophthalmology, Germany
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K. Porubska
- University of Tuebingen, Centre for Ophthalmology, Germany
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U. Klose
- University of Tuebingen, Section Experimental MRI of the CNS, Germany
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F. Gekeler
- University of Tuebingen, Centre for Ophthalmology, Germany
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I. Süveges
- Semmelweis University, Department of Ophthalmology, Hungarian Bionic Vision Center, Budapest, Hungary
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E. Zrenner
- University of Tuebingen, Centre for Ophthalmology, Germany
| Veröffentlicht: | 30. November 2009 |
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Gliederung
Text
Background and Purpose: Replacing functionality of lost photoreceptor cells in case of retinal diseases is the basic idea behind retinal prosthesis. Therefore it is very important to accurately situate the prosthesis to stimulate living cells and not inert areas on the retina. Our purpose is to establish a standardized planning procedure and to preoperatively define the most appropriate location on the fundus for surgical implantation of a subretinal microphotodiode-array (MPDA).
Methods: Eye morphology and retinal structure of the eyeball has been assessed in 4 persons scheduled for prosthesis implantation. Imaging techniques were used to topographically assess individual eye morphology with geometrical dimensions of the eyeball (ultrasound, interferometry, and 3 Tesla MRI using high resolution measurements), and retinal structures with functions (photography, angiography, OCT, microperimetry).
The desired location of the MPDA was defined by means of a multimodal fundus-mapping system. An ellipsoid eye model was used to determine the optimal outcome parameters. For surgical planning the distance from incision to posterior pole and the angle of insertion was calculated and provided to the surgeons. A guiding-tool with a mm-scale was used for creating the channel for insertion
Results: The parameters given proved to be precise enough for subretinal placement in the proximity of the desired location. The fundus-mapping system proved to be a valuable adjunct to define a well-suited location on the posterior pole and was applied for preoperative calculations.
Conclusion: The preoperative evaluation provides a meaningful tool for planning the surgical implantation of a subretinal visual prosthesis and could be useful to other approaches as well (e.g. epiretinal prostheses). It is possible to determine the appropriate surgical approach for the optimal MPDA position preoperatively using a combination of MRI data and projection of geometrical measures onto the eye. After identifying the optimal location with preoperative planning, better functional results were noted in patients.
This lecture is available as video recording (Attachment 1 [Attach. 1]).
