American Society for Peripheral Nerve

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Corneal Neurotization: An Update After Five Years Of Experience
Joseph Catapano, MD1; Simon Fung, MD1; Ronald M. Zuker, MD2; William Halliday, MD2; Asim Ali, MD1; Gregory H Borschel, MD2
1University of Toronto, Toronto, ON, Canada, 2Hospital for Sick Children, Toronto, ON, Canada

Introduction: Corneal anesthesia leaves patients susceptible to occult corneal injury, scarring and progressive vision loss. We have previously reported a novel surgical technique, termed corneal neurotization, to reinnervate the insensate cornea using sural nerve grafts and host trigeminal sensory nerves in 4 patients, all of whom had improved corneal sensation at 8 months follow-up. We now report outcomes of corneal neurotization in 15 patients.

Methods: Fifteen patients that underwent corneal neurotization at the Hospital for Sick Children, Toronto were included in this study. Data on visual acuity, ocular surface integrity and corneal sensation (measured with Cochet-Bonnet esthesiometry) were collected. In the 3 patients who received corneal transplants after corneal neurotization, the explanted corneal tissue was examined histologically to assess the degree of corneal nerve regrowth after the neurotization procedure. Statistical analysis was performed with the Mann-Whitney U test, with p<0.05 being statistically significant.

Results: 19 eyes in 15 patients underwent corneal neurotization between November 2012 and April 2016. Seven patients were male, and median age at surgery was 9.3 years (range: 1.9 34.3). Pre-operatively, median visual acuity was 0.65LogMAR (range: 0.3 2.7), and median central corneal sensation was 0mm (range: 0 20). All patients presented with persistent corneal epithelial defect (PED), with 3 patients suffering corneal perforation and 4 others with abnormal corneal vascularization. Postoperatively, median central corneal sensation improved to 60mm (range: 0-60, N=12, P<0.001). After a median of 16.4 months (range 1.5 43.0), median visual acuity was unchanged (range: 0.1 2.7). Three patients underwent corneal transplantation at a median of 30 months post-operatively (range: 24 33 mo). All corneal transplants remain clear and regained full sensation without any complications. Immunohistochemical analysis of the explanted corneas identified neurofilament-positive axons, indicating corneal reinnervation after initial neurotization surgery.

Conclusions: Corneal neurotization significantly improved corneal sensation, preserved vision, and enhanced ocular surface health. Corneal transplantation was also made possible after reinnervation was established, giving visually-impaired patients a new opportunity to regain their sight.

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