Ossn Excision +CYRO+AMG
OSSN excision+CRYO+AMG: OSSN or Ocular surface squamous neoplasia is an umbrella term for tumours that begin in the conjunctiva and may eventually invade the cornea. The traditional treatment method for OSSN is surgical excision of the tumour. This surgery uses a “no touch technique”, implying that the tumour is not touched with any surgical instruments during the surgery. This is done to reduce the risk of tumour seeding (spread of tumour to adjoining tissues). During this surgery, absolute alcohol is applied over the corneal component of OSSN. The alcohol brings about cellular devitalisation allowing the tumour cells to be easily peeled off. The peeled tumour cells are sent for pathological examination.
Double freeze-thaw cryotherapy is applied to the corneal limbus (border of cornea and sclera) and conjunctival margins. Cryotherapy is believed to reduce the recurrence rate by killing the residual tumour cells, if any. Also, as wide margins are recommended in the surgical excision of the tumour, the ocular surface is often left with a large size defect. An AMG (amniotic membrane graft) is used to cover the defect. The AMG is secured on to the sclera with fibrin glue.