A team of surgeons has demonstrated a surgical model using cadavers for total human eye allotransplantation.
Maxine R. Miller, MD, from the departments of plastic surgery and ophthalmology at the University of Pittsburgh School of Medicine, and colleagues presented data on a proposed method of eye transplantation in humans at the 2016 annual meeting of the Association for Research in Vision and Ophthalmology (ARVO).
In the presentation abstract, the researchers noted that “with advancements in immunomodulation strategies together with new therapies in neuroregeneration, parallel development of human surgical protocols is vital in ensuring momentum towards eye transplantation in patients.”
As part of that effort, the team performed bilateral “globe and periorbita model” transplants between 2 cadavers (2 surgical sessions each, for a total of 4 transplants). They removed the donor eyes via orbital exenteration with combined endonasal and transcranial approach to decompress the orbital apex.
The surgeons then transcranially transected cranial nerves II-VI and the superior ophthalmic vein at the cavernous sinus. According to the abstract, “the ophthalmic artery with carotid artery stem was ligated in the paraclival space.”
In the recipient cadavers, the superficial temporal, internal maxillary and facial artery and superficial temporal and facial vein were exposed; all required vein grafting. Donor tissue was “secured in recipient orbits followed by sequential arterial and venous anastomoses and nerve coaptation with standard microsurgical techniques.”
The team reported that mean donor ophthalmic artery pedicle length and caliber were 13.5 mm and 1 mm (33 mm and 2 mm with a stem of paraclival internal carotid artery). The mean optic nerve was 25 mm from orbital apex to annulus of Zinn, and 14 mm from annulus of Zinn to optic chiasm. Cranial nerves III-VI had mobile pedicle lengths of 10-14 mm.
These results established the “technical feasibility of cadaveric donor procurement and transplantation to cadaveric recipient,” and could serve as a benchmark for “optimization of technique, large animal model development, and ultimately… the possibility of vision restoration transplantation surgery.”