Nerve graft for corneal denervation

Evidence-based recommendations on nerve graft for corneal denervation. This involves attaching a healthy nerve to the damaged cornea to improve healing.

# Recommendations
Evidence on the safety of nerve graft for corneal denervation is limited but raises no major safety concerns. Evidence on efficacy is limited in quantity and quality. Therefore, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research. Find out what special arrangements mean on the NICE interventional procedures guidance page.
Clinicians wanting to do nerve graft for corneal denervation should:
Inform the clinical governance leads in their healthcare organisation.
Give people (and their families and carers as appropriate) clear information to support shared decision making, including NICE's information for the public.
Ensure that people (and their families and carers as appropriate) understand the procedure's safety and efficacy, and any uncertainties about these.
Audit and review clinical outcomes of everyone having the procedure. The main efficacy and safety outcomes identified in this guidance can be entered into NICE's interventional procedure outcomes audit tool (for use at local discretion).
Discuss the outcomes of the procedure during their annual appraisal to reflect, learn and improve.
Healthcare organisations should:
Ensure systems are in place that support clinicians to collect and report data on outcomes and safety for everyone having this procedure.
Regularly review data on outcomes and safety for this procedure.
Further research should be randomised controlled trials, analysis of registry data or case series.
Patient selection should be done by clinicians experienced in managing the condition.
The procedure should only be done in specialist centres by surgeons with skills and experience in this procedure.# The condition, current treatments and procedure

# The condition
The cornea is innervated by the ophthalmic branch of the trigeminal nerve. This innervation maintains the health of the cornea. It does this by providing trophic factors to the corneal cells, activating protective blink reflexes, and stimulating tear production.
Damage to the trigeminal nerve can result in a decrease or loss of corneal sensation. The trigeminal nerve can be damaged by various diseases, chemical burns, physical injuries, or by surgery. Loss of innervation to the cornea can result in neurotrophic keratitis (also known as neurotrophic keratopathy). People with neurotrophic keratitis typically have corneal epithelium defects, poor corneal healing, and can develop sight loss. They are also prone to corneal infections.

# Current treatments
Current treatment for neurotrophic keratitis aims to stop progression to later stages of the disease and promote regeneration of the epithelium. This can include topical lubricants and artificial tears. Antibiotic tear drops may be needed to prevent infections. Options for severe disease include lateral tarsorrhaphy (using sutures to partially or fully close the eyelids), topical nerve growth factor, topical collagenase inhibitors and amniotic membrane grafting.

# The procedure
Nerve graft to restore corneal sensation is done under general anaesthesia. The nerve graft can be either an autograft, when the graft is taken from the person having the procedure, or an allograft, when the graft is a processed nerve from a deceased donor. Several types of grafts have been described in the literature, including the sural nerve, lateral antebrachial cutaneous nerve, great auricular nerve and a nerve from a deceased donor.
The nerve graft is harvested or prepared. At the same time, an incision is made on the contralateral side. This is to access an orbital nerve (the supratrochlear, supraorbital or infraorbital nerve) of the eye that still has normal sensation (the 'donor' nerve). In some people, the ipsilateral supratrochlear, supraorbital or infraorbital nerve, or the ipsilateral great auricular nerve is used as a donor nerve. The nerve graft is attached to the donor nerve and then subcutaneously tunnelled to the perilimbal area of the affected eye. The nerve fascicles can either be placed around the entire limbal circumference and secured to the sclera or are inserted into corneoscleral tunnels. The nerve fascicles are secured with sutures or fibrin glue, or both. The conjunctiva is closed and a temporary lateral tarsorrhaphy may be placed. A patch and topical lubricants may be prescribed after surgery. Over time, new nerve endings grow into the cornea. A corneal transplant may be needed to fully restore sight in people with loss of corneal clarity.