This term is used to describe skull based surgeries for recurrent sinus diseases. The posted video is for extensive frontal sinus disease - called MODIFIED ENDOSCOPIC LOTHROP procedure, the entire floor of the two sinuses are removed along with the intervening septum to create a common cavity. This helps to administer medication as well as post operative examination for recurrences. This is indicated for recurrent frontal sinus surgery, tumors, CSF leaks in frontal sinuses etc.

Endoscopic repair of cerebro-spinal fluid (CSF) leak from the lateral recess of sphenoid sinus can also be viewed below. This is a very demanding surgical procedure as the site of leak was in a plane behind the eye. Here, access was obtained by going through the maxillary sinus, located below the eye.