A New Composite Eyeball-Periorbital Transplantation Model in Humans: An Anatomical Study in Preparation for Eyeball Transplantation

A New Composite Eyeball-Periorbital Transplantation Model in Humans: An Anatomical Study in Preparation for Eyeball Transplantation: No abstract available




I have read the article referenced here1 with interest, and I would like to congratulate the authors on their work and its appearance in print. This is the first report on a composite eyeball-periorbital graft that aims to address blindness in the setting of traumatic injury.



The model is functional because it included the eyeball, the first and second divisions of the trigeminal nerve, cranial nerves III through VI, the optic nerve, and the orbicularis oculi. Surprisingly, it missed the frontal and zygomatic branches of the facial nerve, essential for the motor function of the orbicularis oculi. I believe that, to further optimize the functional potential of such a graft, those motor nerve branches should be included in similar grafts.



Average operative time was 360 minutes, which is a long time given that there was no intraorbit dissection. Would the authors kindly explain why the operation took so long, what the sticky points were, and how they can be avoided? Their answers could be helpful to readers when considering this model in their mock operations. Furthermore, the timing of the division of the ophthalmic artery and optic nerves needs to be pointed out, because the timing of such affects ischemia time, for which the retina does not tolerate much.2 I mention this because I read that the ophthalmic artery was divided before the box ostomy was performed, which made me wonder about prolonged ischemia time in actual settings when the advocated sequence is followed.



The superficial temporal artery was used to perfuse the graft along with the facial artery and the ophthalmic artery. I have observed that the superficial temporal artery plays a limited role in supplying the orbital bones and the periorbital tissue in this model based on the suggested design. The facial artery and its terminal branch the angular artery3 and the ophthalmic artery could be enough in cadavers at least, but when in doubt and given the large bony stalk harvested, I would recommend inclusion of the transverse facial and superficial temporal arteries but with the osteotomies placed more laterally and superiorly to capture superficial temporal artery branches, and opting for a subperiosteal plane early on rather than the sub–superficial musculoaponeurotic system–to-subperiosteal plane advocated initially.



Box orbital osteotomy is an aggressive procedure. Although some of the advantages mentioned in the article are clear, in my opinion, such resection may not be necessary to preserve the origin of the extrinsic muscles of the eyeball, as they originate from the annulus of Zinn. This definitely was one step forward toward eyeball allotransplantation, and the authors are to be commended, but further studies and extensive planning are immensely needed.



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DISCLOSURE

The author has no financial interest to declare in relation to the content of this communication.



Nidal F. AL Deek, M.D., M.Sc.



Chang Gung University Medical College



Department of Plastic and Reconstructive Surgery



Chang Gung Memorial Hospital



199 Tun-Hwa North Road



Taipei 10591, Taiwan



nidaldeek@gmail.com



Twitter: @NidalAlDeek



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REFERENCES

1. Siemionow M, Bozkurt M, Zor F, et al. A new composite eyeball-periorbital transplantation model in humans: An anatomical study in preparation for eyeball transplantation. Plast Reconstr Surg. 2018;141:1011–1018.

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2. Tobalem S, Schutz JS, Chronopoulos A. Central retinal artery occlusion: Rethinking retinal survival time. BMC Ophthalmol. 2018;18:101.

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3. Gharb BB, Rampazzo A, Kutz JE, Bright L, Doumit G, Harter TB. Vascularization of the facial bones by the facial artery: Implications for full face allotransplantation. Plast Reconstr Surg. 2014;133:1153–1165.

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