Surgical treatment for postoperative maxillary cysts uses a Caldwell-Luc or endonasal approach. Endoscopic endonasal surgery has become the treatment of choice in postoperative maxillary cyst, and many postoperative maxillary cysts have been classified. Due to the importance of cyst medial wall sites, we classified cysts into 4 types by location. Those whose, medial wall was close to the middle meatus, inferior meatus, or nasal lateral wall, we termed middle meatus, inferior meatus, and nasal lateral wall types. When the lateral cyst was not close to the nasal cavity but to another cyst, we termed the cyst continuous. We opened all nasal cavity cysts as far as possible. For continuous types, we determined location of the lateral cyst 3-dimensionally before surgery. We first opened medial cysts and opened the lateral cyst through the medial cyst. The tube was placed the lateral cyst to the nasal cavity. We opened all 45 cysts in 29 patients to the nasal cavity. As of this writing, no cysts connected to the nasal cavity have recurred.