Previous observers have suggested that the main site of respiratory airflow resistance is localized to the vestibular region of the nose. This resistive segment of the airway was investigated using a "head-out" body plethysmograph in subjects with anatomically normal noses (a) untreated, (b) congested and (c) decongested. In all three conditions, 2/3 of the total nasal airflow resistance was found within the bony cavum in the vicinity of the pyriform aperture and about 1/3 in the cartilaginous vestibule. As might be expected, caval resistance changed proportionately with the degree of mucosal congestion; but, more surprisingly, vestibular resistance changed similarly. This was due in part to the observed forward expansion of the anterior ends of the inferior turbinates with congestion. EMG recordings in subjects breathing through both nostrils demonstrated a gradation of inspiratory alar dilator muscle activity with increased minute ventilation and with mucosal congestion, and there was no evidence of inspiratory alar collapse. But with elevated ventilation through one nostril only, or when the alar muscles were paralyzed by lidocaine block of the VIIth nerve, alar collapse occurred. These findings are of importance in the management of the congested but anatomically normal nose and in surgery of the nasal tip.

Acoustic rhinometry (AR) is a recently developed objective technique for assessment of geometry of the nasal cavity. The technique is based on the analysis of sound waves reflected from the nasal cavities. It measures cross-sectional areas and nasal volume (NV). To obtain dependable assessments of nasal resistance by rhinomanometry or cross-sectional area measurements by AR, it is essential that the structural relations of the compliant vestibular region remain undisturbed by the measuring apparatus. The use of nozzles in making these measurements carries a great risk of direct distortion of the nasal valve. We used a nasal adapter that does not invade the nasal cavity and a chin support that stabilizes the head. In 51 healthy nasal cavities, the average minimum cross-sectional area (MCA) was 0.62 cm2 at 2.35 cm from the nostril and 0.67 cm2 at 2 cm from the nostril, respectively, before and after topical decongestion of the nasal mucosa. The MCA and NV findings in this group were significantly higher than MCA and NV (P < 0.001) in people with structural or mucosal abnormalities before mucosal decongestion. After mucosal decongestion, the MCA and NV were significantly higher in healthy nasal cavities than in nasal cavities with structural abnormalities (P < 0.001) but were not higher than nasal cavities with mucosal abnormalities (MCA, P = 0.05; NV, P = 0.06). A nozzle was applied in 20 healthy nasal cavities after mucosal decongestion, and a significantly higher MCA was found compared to measurements made with the nasal adapter (P = 0.02). We conclude that the nasal adapter, which does not invade the nasal cavities, avoids the distortion of the nasal valve and gives more accurate results.

No abstract

The nasal valve consists of four distinct airflow-resistive components. (i) The vestibule terminates in an airflow-resistive aperture between the septum and the caudal end of the upper lateral cartilage. Its cross-sectional area is stabilized by the cartilaginous structures and by inspiratory isometric contractions of alar dilator muscles. Its walls are devoid of erectile tissues that might otherwise affect its cross-sectional area and airflow resistance. By contrast, (ii) the bony entrance to the cavum is occupied by erectile tissues of both (iii) lateral (turbinate) and (iv) septal nasal walls that modulate the cross-sectional area of the airway and airflow resistance. The body of the cavum offers little resistance to airflow. Valve constrictions induce "orifice flow" of inspiratory air as it enters the body of the cavum, disrupting laminar characteristics and thereby enhancing exchanges with the nasal mucosa of heat, water, and contaminants. Acoustic rhinometric and rhinomanometric measurements show the sites, dimensions, and resistances of the valve constrictions and indicate that it is seldom necessary to extend septal and/or turbinate surgery far beyond the piriform aperture in the treatment of nasal obstruction.

The aims of this study are to assess nasal valve cross-sectional areas in healthy noses and in patients with nasal obstruction after rhinoplasty and to evaluate the effect of an external nasal dilator on both healthy and obstructive nasal valves. Subjects consisted of (i) volunteers with no nasal symptoms, nasal cavities unremarkable to rhinoscopy and normal nasal resistance and (ii) patients referred to our clinic complaining of postrhinoplasty nasal obstruction. All subjects were tested before and after topical decongestion of the nasal mucosa and with an external nasal dilator. In 79 untreated healthy nasal cavities the nasal valve area showed two constrictions: the proximal constriction averaged 0.78 cm2 cross-section and was situated 1.18 cm from the nostril, the distal constriction averaged 0.70 cm2 cross-section at 2.86 cm from the nostril. Mucosal decongestion increased cross-sectional area of the distal constriction significantly (p < 0.0001) but not the proximal. External dilation increased cross-sectional area of both constrictions significantly (p < 0.0001). In 26 post-rhinoplasty obstructed nasal cavities, only a single constriction was detected, averaging 0.34 cm2 cross-section at 2.55 cm from the nostril and 0.4 cm2 at 2.46 cm from the nostril, before and after mucosal decongestion respectively. External dilation increased the minimum cross-sectional area to 0.64 cm2 in these nasal cavities (p < 0.0001). We conclude that the nasal valve area in patients with postrhinoplasty nasal obstruction is significantly smaller than in healthy nasal cavities as shown by acoustic rhinometry. Acoustic rhinometry objectively determines the structural and mucovascular components of the nasal valve area and external dilation is an effective therapeutical approach in the management of nasal valve obstruction.

The reproducibility of nasal patency measurements was assessed by acoustic rhinometry and active rhinomanometry using previously described Toronto methodologies. Six subjects with normal upper airways were tested with both procedures on six separate occasions within a 2-month period. Topical decongestant was applied to minimize the effects of mucosal variation on the nasal airway. The mean coefficients of variation (mean +/- s.d; %) over time of the measurements were 8.1 +/- 4.1 and 9.7 +/- 5.2 for minimal unilateral cross-sectional area and 4.8 +/- 1.8 and 5.5 +/- 3.5 for nasal volume (0-5 cm) of the right and left sides, respectively. For active rhinomanometry, the mean coefficients of variation (mean +/- s.d.; %) over time of the measurements were 15.9 +/- 7.3, 12.9 +/- 4.6, and 8.5 +/- 2.8 for right, left and combined nasal airflow resistance. The intraclass correlation coefficient was 0.76, 0.70, and 0.96 for right, left, and combined nasal resistance, 0.91 and 0.87 for right and left minimal cross sectional area, and 0.86 and 0.69 for right and left nasal volumes, respectively, also confirming a high level of reproducibility for both methods. In conclusion, performed by an experienced operator under controlled circumstances, the reproducibility of both methods of nasal patency assessment compared favorably with many widely accepted clinical tests.

The purpose of this study was to compare apnea and snoring in patients with different patterns of nasal resistance: normal, high unilateral, and high bilateral. The authors examined 683 unselected patients referred for evaluation of snoring and possible sleep apnea. All patients had determination of nasal resistance (performed during wakefulness in the seated posture) and nocturnal polysomnography including quantitative measurement of snoring. Analysis of variance showed no significant difference in apnea and snoring indices among the three nasal resistance groups (normal, high unilateral, and high bilateral). Furthermore, there was no significant difference in the frequency of patients with different severity of apnea and snoring among the three groups. It is concluded that 1. unilateral and bilateral elevation of nasal resistance may lead to equally severe snoring or apnea; 2. there is no direct relationship between awake seated nasal resistance measurement and sleep disordered breathing; and 3. measurements of supine nasal resistance during sleep may be required to elucidate the relationship between sleep-disordered breathing and nasal obstruction.

This study was designed to assess the subjective and objective effects of uvulopalatopharyngoplasty (UPPP) for treatment of snoring. We mailed a questionnaire dealing with snoring, quality of sleep, and interference with bed-partner's sleep to 100 unselected patients who were referred because of snoring. Replies were received from 69 patients. The answers were analyzed, and the subjective impressions were compared with preoperative and postoperative objective measurements of snoring and apnea. The average (+/- SD) length of follow-up was 45 +/- 20 mo. We found no significant differences in the apnea/hypopnea index, snoring index, and mean and maximal nocturnal sound intensity before and after surgery in this group. However, despite this lack of objective improvement. 78% of patients reported reduction in snoring, and 79% reported improvement in the quality of sleep; 18 of 69 bed partners no longer complained of interference with their sleep compared with only one preoperatively. We conclude that if the purpose of UPPP is to reduce the reported health hazards associated with snoring, then comparison between objective preoperative and postoperative measurements of snoring does not indicate success; if, on the other hand, the purpose of surgery is to alleviate the social hazard, then UPPP partially achieves this goal.