Corneal Neurotization From The Greater Auricular Nerve With Sural Nerve Graft: A New Technique For Congenital Trigeminal Anaesthesia

We present an indirect corneal neurotization (CN) technique using the greater auricular nerve (GAN) in a 4 year-old patient with severe neurotrophic keratopathy (NK) due to bilateral congenital trigeminal anaesthesia (CTA) associated with pontine tegmental cap dysplasia (PTCD). This is the first case of CN using GAN for the treatment of NK due to PTCD in the literature. 

The case was managed jointly by the Cornea and External Diseases Department at Moorfields Eye Hospital, London with the Maxillofacial Department at St. George’s Hospital NHS Foundation Trust, London, United Kingdom

A 4 year-old boy with PTCD presented with severe NK with dense scarring and recurrent ulcerations despite full medical treatment. Detailed electrophysiological testing of his cranial nerves confirmed absence of blink response and no reaction to stimulation of the ophthalmic division of the trigeminal nerve. Nerve conductions showed normal greater auricular and sural nerves.

CN was carried out for his only seeing eye using a harvested autologous sural nerve as an inter-positional nerve graft coapted to the ipsilateral GAN and tunnelled subcutaneously via the inferior fornix to the subtenon space. The distal end of sural nerve was fashioned into multiple fascicles and then secured onto the sclera aroung the whole limbal circumference. 

The postoperative course was uneventful.  The presence of corneal sensation was evident at 3 months post operatively.  At 6 months there was an improvement in vision subjectively enabling the patient to perform more visually demanding tasks at school and he was able to watch cartoons.  By 12 months post op the corneal opacities reduced in size and density and epithelium maintained a healthy appearance. 

This new approach using the GAN with sural nerve graft for CN has the potential to provide corneal sensation and trophic function in CTA.  It offers some advantages over the more traditional approach with direct and indirect CN techniques using supratrochlear/ supraorbital nerves as donors which cannot be used in bilateral cases of trigeminal anaesthesia. The GAN originates from the cervical plexus; it is a larger calibre nerve therefore has higher axon counts and potentially offers a more robust neurotisation.  This technique avoids extensive bicoronal or facial dissection and offers a faster recovery time.  Our patient successfully gained corneal sensation and vision and the corneal integrity was restored.