 Entering the surgical field via the nose, rather than through an incision in the mouth as in the previous Caldwell-Luc method, decreases risk of damaging nerves which innervate the teeth.Because of its less-invasive nature, FESS is a common option for children with CRS or other sinonasal complications.Functional Endoscopic Sinus Surgery is considered a success if most of the symptoms, including nasal obstruction, sleep quality, olfaction and facial pain, are resolved after a 1-2 month postoperative healing period.