Modified Boston Type 2 Keratoprosthesis Technique With Oral Mucosa

To describe a new alternative surgical technique combining oral mucosa and the Boston Keratoprosthesis type II (BKPro II) avoiding complete tarsorrhaphy in a patient with severe chemical burn.

Department of Ophthalmology. Cruces University Hospital, Barakaldo, Spain.

We present a case of a 34 year-old-man who suffered a severe bilateral chemical burn with caustic soda while at work. On ocular examination both eyes showed a severe corneal caustication. Visual acuity was light perception and projection in both eyes. After many surgeries including eyelid reconstruction to improve lagophthalmos and entropion, eyelashes electrolysis, amniotic membrane transplants, cataract extraction and penetrating keratoplasty in right eye (RE), he presented a corneal thinning in his RE that was managed with an autologous oral mucosa graft in other center.  Considering the limited function of the eyelids, mild symblepharon and dry ocular surface, we proposed the implantation of a BKPro II. The patient voiced his desire of avoiding complete tarsorrhaphy for better cosmesis. Osteodonto Keratoprosthesis (OOKP) or Tibial bone Keratoprothesis (Tibia KPro) was also discarded at the patient's express wish. So, after three months since the oral mucosa had been implanted and once the ocular surface was stabilized, we lift the mucosa and performed the implantation of the BKPro II covering this device with the mucosa trephined in the center avoiding the complete tarsorrhaphy and modifying the standard procedure.

After 2 year - follow up, the patient did not develop any complication, his VA is 0.3 decimal and funduscopic examination showed a pale optic disk, vascular tortuosity and epiretinal membrane that remain stable during this period. Transmucosal BKPro II should be consider as an alternative surgical technique for Boston KPro II carriers who want to improve their cosmesis avoiding complete tarsorrhaphy and do not want to be exposed to dental or bone surgeries.