Corneal Neurotization as a Treatment for Neurotrophic Keratopathy

Study Overview
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Brief Summary
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The purpose of this study is to assess the efficacy of sural nerve transfer and cadaveric nerve graft to re-establish corneal sensation in patients with neurotrophic keratopathy.

Detailed Description
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Corneal anesthesia, which can lead to visually devastating outcomes from ulceration, perforation, and scarring, can be recalcitrant to both medical and surgical treatment[1-3]. Neurotization is a revolutionary technique reported to restore corneal sensation in neurotrophic keratopathy[4-6]. Prior techniques described include direct neurotization with contralateral supraorbital and supratrochlear nerves accessed via a bicoronal incision of the scalp over the forehead[5]; nerve grafting with contralateral supratrochlear nerves accessed via a medial upper eyelid incision[6]; and sural nerve grafting to contralateral supratrochlear nerves accessed via a transverse incision over the medial upper eyelid[4]. Despite the challenges associated with these techniques (needing to subcutaneously tunnel the nerve graft over the nasal bridge or requiring a large bicoronal incision), these techniques all demonstrated efficacy in direct neurotization to improve corneal sensation in these patients. The investigators aim to assess the efficacy of this innovative surgical technique involving coaptation of the sural nerve or cadaveric nerve allograft to an intact sensory branch of the trigeminal nerve to restore corneal sensation. The investigators have previously described the anatomic feasibility of using the infraorbital nerve using a cadaveric model, of which the results were presented at the American Society of Ophthalmic Plastic and Reconstructive Society Fall meeting in 2017. Utilization of the infraorbital nerve provides advantages over existing techniques due to ease of access via a cosmetically favorable incision, large caliber with increased ability to create a perineural window, relatively short and direct tunnel with possibly more rapid neurotization, and absence of complex surrounding anatomical structures. Others have previously describe success using the contralateral and ipsilateral supraorbital nerve and supratrochlear nerve.

Official Title
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Corneal Neurotization Via Sural Nerve Transfer or Cadaveric Nerve Graft for Neurotrophic Keratopathy

Conditions
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Neurotrophic Corneal Ulcer, Neurotrophic Keratitis, Cranial Nerve V Diseases

Intervention / Treatment
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* Procedure: Corneal neurotization


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with neurotrophic cornea Exclusion Criteria: Patients with history of penetrating keratoplasty
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Corneal neurotization<br>Patients will undergo the corneal neurotization as described in the protocol. Their pre and post-procedure corneal sensation will be measured as a primary outcome measure. Secondary outcome measures will include visual acuity, corneal opacity, NEI VFQ, and confocal microscopy. | Procedure: Corneal neurotization<br>* Autologous sural nerve will be harvested or cadaveric nerve graft will be coapted to an intact sensory branch of the trigeminal nerve. The nerve will be separated into fascicles which will be tunneled under the conjunctiva around the cornea near the limbus.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Corneal sensation | Corneal sensation will be measured via Cochet Bonnet esthesiometry | Baseline (pre-operative) to 12 months postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual acuity | Measurement using Snellen eye chart | Baseline (pre-operative) to 12 months postoperatively | 
| Corneal opacity | Measured based on grade 0-4 based on degree of opacity. | Baseline (pre-operative) to 12 months postoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Corneal neurotization, neurotrophic cornea, neurotrophic corneal ulcer