,The anterior and posterior ethmoid air cells were entered primarily and dissected with the Richards essential shaver followed by the use of a 30-degree endoscope and up-biting forceps for the superior and lateral dissection. 
,The anterior and posterior ethmoid air cells were entered primarily and dissected with the Richards essential shaver followed by the use of a 30 - degree endoscope and up - biting forceps for the superior and lateral dissection .