**7. Revision endoscopic dacryocystorhinostomy**

The principles are similar to those of primary DCR. As far as the bone along the lateral nasal wall has already been removed, endoscopic revision DCR is much easier than the primary procedure. The important point in revision DCR is the size of the lacrimal sac.

If the sac is normal in size, the rate of success is high (89%)11, 12. If there is scarring and cicatrizaion of the sac, the success rate is lower because only a small amount of lacrimal mucosa can be marsupialized.

In severe stenosis and scarring of the lacrimal sac, the agger nasi mucosa can be used as a free graft to create functional mucosa surrounding the common canaliculus-sac junction.
