It appears that uvulopalatopharyngoplasty (UVPP) is a reliable procedure for reducing snoring, but much less reliable when used as a treatment for OSAS. This is thought to be because of poor patient selection in that the site of the problem is not always the site of the operation. We present the technique of sleep nasendoscopy which allows direct visualization of the site or sites of obstruction in a sleeping patient. Our study has shown that there are patients with obstructive sleep apnoea syndrome (OSAS) in whom the only site of pharyngeal obstruction is at the velopharynx. These patients should do well with the relatively simple procedure of UVPP. This is not true for many other OSAS patients in whom we found that obstruction was multisegmental. This helps to explain the frequently poor results of UVPP in OSAS patients. We feel that this form of preoperative assessment will avoid unnecessary surgery.

It appears that uvulopalatopharyngoplasty (UVPP) is a reliable procedure for reducing snoring, but much less reliable when used as a treatment for OSAS. This is thought to be because of poor patient selection in that the site of the problem is not always the site of the operation. We present the technique of sleep nasendoscopy which allows direct visualization of the site or sites of obstruction in a sleeping patient. Our study has shown that there are patients with obstructive sleep apnoea syndrome (OSAS) in whom the only site of pharyngeal obstruction is at the velopharynx. These patients should do well with the relatively simple procedure of UVPP. This is not true for many other OSAS patients in whom we found that obstruction was multisegmental. This helps to explain the frequently poor results of UVPP in OSAS patients. We feel that this form of preoperative assessment will avoid unnecessary surgery.

This prospective clinical study examined the alterations in airway and hyoid position in response to mandibular advancement in subjects with mild and moderate obstructive sleep apnoea (OSA). Pairs of supine lateral skull radiographs were obtained for 13 female and 45 male, dentate Caucasians. In the first film, the teeth were in maximal intercuspation, while in the second the mandible was postured forwards into a position of maximum comfortable protrusion. Radiographs were traced and digitized, and the alterations in the pharyngeal airway and position of the hyoid were examined. Males and females were analysed separately. In males only, correlations were sought between the changes in hyoid and airway parameters, and the initial and differential radiographic measurements. In males, mean mandibular protrusion at the tip of the lower incisor was 5.3 mm, increasing its distance from the posterior pharyngeal wall by 6.9 mm (or 9 per cent). Movement of the hyoid showed extreme inter-subject variability, both in the amount and direction. In relation to the protruded lower jaw, the hyoid became closer to the gonion by 6.9 mm and to the mandibular plane by 4.3 mm. With respect to the upper face, a 1.3-mm upward and 1.1-mm forward repositioning was seen. The percentage alterations in airway dimensions matched or bettered the mandibular advancement. The minimum distances behind the soft palate and tongue improved by 1.0 and 0.8 mm, respectively. Despite their smaller faces, females frequently showed greater responses to mandibular protrusion than males. No cephalometric features could be identified which might indicate a favourable response of the airway to mandibular protrusion. Larger increments of hyoid movement were associated with an improved airway response, but the strength of the correlations was generally low.

The prevalence of sleep related upper airway obstruction (UAO)