Corneal Neurotization Using the Supratrochlear Nerve With a Great Auricular Nerve Graft for Neurotrophic Keratopathy: Long-Term Results.

Abstract

To evaluate the long-term functional, anatomical and cellular outcomes of indirect corneal neurotization (ICN) for neurotrophic keratopathy (NK), including cases of secondary penetrating keratoplasty (PKP). Prospective interventional case series at a tertiary ophthalmology center. Patients underwent ICN for NK with a minimum follow-up of 12 months after surgery. ICN was performed using the supratrochlear nerve (STN) as the donor nerve (ipsilaterally or contralaterally, depending on its functionality) and the great auricular nerve (GAN) as a free nerve graft. PKP was performed after ICN in 4 patients with persistent visual impairment due to severe corneal scarring. The primary outcome was an anatomical and functional assessment of ICN at 24 months, including central (CCS) or peripheral (PCS) corneal sensitivity (CS), in vivo confocal microscopy (IVCM) recovery and comparison with the fellow contralateral eye. The secondary outcomes were best-corrected visual acuity (BCVA), bilateral total and epithelial thicknesses on optical coherence tomography (OCT), PKP subgroup outcomes, immunochemistry of the corneal buttons and GAN fascicle, complications of ICN. Nineteen eyes from 19 patients (63% with a history of intracranial tumor) with a mean follow-up of 40.1±20.3 months were included. CS improved in 16 eyes (84%), including 9 (56%) with completely denervated corneas at baseline: both CCS and PCS improved significantly (P = .011, P < .001 respectively). IVCM showed morphological corneal reinnervation in all 19 eyes over 24 months. Sub-basal nerve density, number of corneal nerves and branches, and reflectivity were higher than at baseline (all P < .01), while dendritic cell density was lower (P = .002). No significant differences were found for BCVA or thicknesses on OCT (all P > .05). No serious adverse events occurred: 7 patients (37%) reported transient earlobe numbness; IVCM revealed transient corneal neuromas in 8 patients (42%) including 2 (25%) with corneal dysesthesia. The aesthetic outcome was satisfactory for all but 1 eye. Four eyes underwent corneal transplantation after successful ICN, with no major complications. All 4 corneal buttons and the GAN fascicle remained positive for ß-III tubulin, indicating axonal regrowth. STN/GAN-based ICN results in sustained corneal reinnervation, making secondary PKP possible for NK rehabilitation.