Abstract： Objective To investigate the reasons of flap division in patients with posterior pharyngeal flap and the outcome of the flap division for treating secondary velopharyngeal insufficiency (VPI) and obstructive sleep apnea-hypopnea syndrome (OSAHS).Methods Twenty patients who underwent flap division after posterior pharyngeal flap surgery were included in this study, including 11 uncomplete cleft palate and 9 complete cleft palate).Nasal endoscopy and lateral cephalometric radiographs were performed for all the patients preoperatively. Speech recordings were made pre- and postoperatively.The respiratory status of patients who hadOSAHS manifestations was monitored by polysomnography. Simple division of the flap was carried out in 14 cases, and additional pharyngoplasty combined the division of posterior pharyngeal flap was performed in six cases. ResultsThe speech did not show significant improvement in 14 cases after posterior pharyngeal flap surgery but improved after flap division. Three cases got speech improvement, but developed the respiratory obstruction causing sleep apnea. After the division of flap, the respiratory status got improved. Three cases required orthognathic surgery under general anesthesia, which demanded the division of flap simultaneously. The speech did not change after the division. ConclusionsIf OSAHS occurred or VPI remained after posterior pharyngeal flap surgery, the division of the flap or additional pharyngoplasty should be performed. It is suggested that the operation of the flap division be done six months after posterior pharyngeal flap surgery.