BACKGROUND: Partial soft palate, uvula and the otiose soft tissue of lateral pharyngeal wall are resected in traditional uvulopalatopharyngoplasty. Although the syndrome can be improved, the complications, such as velopharyngeal insufficiency, cicatricial contration of pharyngeal cavity, can occur in some patients, furthermore, the prostecdtive efficacy is below the mark.OBJECTIVE: To investigate efficacy of the dilatation of oropharyngeal and nasopharyngealisthmus in uvulopalatopharyngoplasty treating obstructive sleep apnea hypopnea syndrome.DESIGN: A case-control observation.SETTING: The Affiliated Municipal Hospital of Medical College, Qingdao University.PARTICIPANTS: The patients who were hospitalized for snoring, apnea, breathing obstruction and somnolence were selected from the Sleep Respiratory Disorder Diagnosis and Treatment Center in the Affiliated Municipal Hospital of Medical College of Qingdao University from July 2001 to February 2006. We ascertained that the obstruction located at pharynx oralis, no hypertrophy of lingual root, and made a definite diagnosis of OSAHS by polysomnogram. The apnea hypopnca index (AHI) was ≥ 5 times per hour. Among 216 patients, there were 159 males and 57 females aged older than 25 years.METHODS: The patients were treated by modified UPPP which maintained the normal anatomic form of pharyngeal cavity, reserved the uvula, performed oblique straight incision along palatoglossal arch to soft palate, and avoided the incision of inverse U type. Palatoplasty and pharyngoplasty could extend the oropharyngeal isthmus and nasopharyngeal isthmus thoroughly.MAIN OUTCOME MEASURES: ① The survey of effect in the near future: Defined the pain without pain-killer as pain lightly, or as pain heavily inversely. If the lateral wall of oropharynx could remain the designed morphous, it was a good henosis; it was a bad henosis inversely. ② The survey of effect in a long term: According to the statement of the patients themselves. Estimated whether the patients had postoperative complications, such as backstreaming in nasal cavity, pharyngeal foreign body sensation, etc. Assessed if the patients had sleep apnea according to the observation of the family member and the monitoring of PSG. And ascertained whether the pharyngeal cavity had approached to normal structure by the examination of oropharynx.RESULTS: All 216 patients were involved in the final analysis. ① Of the 216 subjects, there were 156 patients who needed pain-killer (72%), and 60 Patients need not (26%). The lateral pharyngeal wall of 136 subjects was smooth (63%), and the other 80 were splited partly (37%). There were no complications such as breath holding, backstreaming in the nasal cavity. ② The survey of longdated postoperative effect: The 216 patients were followed up for 6 mouths.There was no deglutitive bucking, open rhinolalia. A total number of 84 patients (39%) had pharyngeal foreign body sensation. The syndrome of sleep apnea disappeared in 169 patients, and the other 47 patients still had the syndrome,but improved than before. In 203 patients (94%), the postoperative morphous of oral cavity were content, and the other 13 patients (6%) were not content. ③ The statistical significance of the preoperative and postoperative result of PSG monitoring of the 216 patients with OSAHS existed and the difference was significant [AI: 35.45±16.42, 12.75±9.62; HI:19.39±9.86, 17.43±10.15; AHI: 54.29±18.13, 28.31 ±16.23; the average low saturation of blood oxygen: (83.58±7.96) %,(85.53±8.18) %; the average saturation of blood oxygen: (91.98±3.29) %, (93.01±3.02) %, P ＜ 0.05].CONCLUSION: The modified uvulopalatopharyngoplasty indicates that this approach not only extend the nasopharynx cavity, but also avoids the postoperative complications. The patients have markedly improved symptoms.