Flextube reflectometry for level diagnosis in patients with obstructive sleep apnoea and snoring.

The aim of this study was to use sound reflections in a flexible tube (flextube reflectometry) for identifying the predominant obstructive level of the upper airway in a series of patients referred to a sleep clinic. We also wished to study the relationship between the number of flextube narrowings per hour recording and the RDI (respiratory disturbance index = apnoeas and hypopneas per hour recording) by ResMed AutoSet (AS), which is a device based on nasal pressure variations. We performed sleep studies on 54 patients referred for snoring or OSA; 1) at home with AS; 2) in hospital using flextube reflectometry and AS simultaneously. The predominant obstructive level of the upper airway was retropalatal in 15 of the patients and retrolingual in 25 of the patients determined by flextube reflectometry. In 14 there was no predominant level of narrowing. We found a statistically significant correlation between the number of flextube narrowings per hour recording and the RDIs by the AS (Spearman's correlation coefficient r = 0.62, p < 0.001, n = 54). Flextube reflectometry may provide useful information regarding the level of obstructive predominance during obstructive events. The method also determines the frequency of respiratory disturbances and records snoring sound.

Flextube reflectometry and pressure-recordings for level diagnosis in obstructive sleep apnoea.

The objective of this study was to compare sound reflections in a flexible tube (flextube reflectometry) with pressure-catheter recordings (ApneaGraph) for identifying the predominant obstructive level of the upper airway during sleep. Seventeen males with suspected obstructive sleep apnoea syndrome (OSAS) were included in the study. The mean (standard deviation = SD) number of flextube narrowings per hour recording was 50.2 (20.4) and the mean (SD) RDI (respiratory disturbance index = apnoeas and hypopnoeas per hour recording) determined by the ApneaGraph was 45.7 (20.2). The mean difference (SD) between the number of flextube narrowings per hour recording and the RDIs determined by the ApneaGraph was not statistically significantly different from 0. There was no statistically significant correlation between the percentage of retropalatal narrowing of the total narrowing (retropalatal and retrolingual narrowing) measured by flextube reflectometry and the percentage of retropalatal ("upper") obstructive apnoeas and hypopnoeas of the total number ("upper", "intermediate" and "lower") measured by ApneaGraph (Spearman's correlation coefficient r = 0.24, p = 0.36, N = 17). In conclusion diverging results were found in flextube reflectometry studies and pressure-recordings performed on different nights regarding the level distribution of obstructions during sleep. Possible explanations of this discrepancy are discussed.

Flextube reflectometry for localization of upper airway narrowing--a preliminary study in models and awake subjects.

The aim of this study was to examine an acoustic reflection method using a flexible tube for identifying the obstructive site of the upper airway in snorers and patients with obstructive sleep apnoea (OSA). As a preliminary study it was performed n models and subjects in the awake state. Flextube narrowing was produced in a model of the nose and pharynx and three blinded observers assessed the obstructive level. The correlation between pharyngeal narrowing assessed by endoscopy and by acoustic measurement during Müller manoeuvres was also examined in 10 OSA patients and 11 healthy non-snoring, adults. Three blinded observers dentified the level of 176 of 180 random cases of flextube narrowing in a polycarbonate model correctly The level of narrowing was always correctly evaluated within 1.9 mm. Pharyngeal area decrease was measured by the flextube method during the Müller manoeuvre but it was not closely related to the findings by endoscopy. In conclusion the flextube reflectometry method was able to demonstrate narrowng in a model of the nose and pharynx in a precise way. Narrowing was also observed during Müller manoeuvres. Flextube reflectometry may be a promising method to detect upper airway narrowing but further evaluation during sleep is required.

Flextube reflectometry for determination of sites of upper airway narrowing in sleeping obstructive sleep apnoea patients.

The aim of this study was to examine a new technique based on sound reflections in a flexible tube for identifying obstructive sites of the upper airway during sleep. There was no significant difference between two nights in seven obstructive sleep apnoea (OSA) patients regarding the level distribution of pharyngeal narrowings, when the pharynx was divided into two segments (retropalatal and retrolingual). We also compared the level distribution determined by magnetic resonance imaging (MRI) with the level distribution found by flextube reflectometry in seven OSA patients. There was no significant difference between flextube and MRI level distributions during obstructive events, but due to few subjects the power of the test was limited. We found a statistically significant correlation between the number of flextube narrowings per hour of sleep and the number of obstructive apnoeas and hypopnoeas per hour of sleep determined by polysomnography (PSG) in 21 subjects (Spearman's correlation coefficient r = 0.79, P < 0.001). In conclusion, the flextube reflectometry system seems to be useful for level diagnosis in OSA before and after treatment.

Clinical applications of acoustic rhinometry.

The clinical value of acoustic rhinometry (AR) is its ability to measure the dimensions of the nasal cavity in terms of a curve describing the cross-sectional areas as a function of distance. This curve describes nasal airway patency and gives an impression of the degree of nasal obstruction. The method provides values before and after decongestion which allow to evaluate the cause of the nasal obstruction as mainly skeletal or mucosal. This makes AR a tool for diagnosis and follow-up of treatment in both rhinology and rhinosurgery. Similarly, AR is a reliable method to show the dimensional changes of the nasal cavity before and after a given treatment. In the evaluation of a surgical intervention it is reasonable to use decongested values. Turbinate surgery, septo- and rhinoplasty, orthognatic surgery and paranasal sinus surgery and their influence on the dimensions of the nasal cavity may be reflected by AR. The absolute minimum cross-sectional area, and cross-sectional areas and volumes at fixed distances are the recommended parameters to show dimensional changes after nasal surgery. The predictive value of AR, in relation to nasal obstruction, should have high specificity and sensitivity to be used in a clinical setting. It seems that the single variables do not provide enough information for the diagnosis of obstruction, and it has been stressed that the results should be interpreted together with rhinoscopy and subjective complaints. A statistical model based on questionnaire, rhinoscopic findings and several variables from AR has been proposed to increase the diagnostic specificity and sensitivity of AR.

Influence of lateral osteotomies in the dimensions of the nasal cavity.

OBJECTIVES: To elucidate the importance of placement of lateral osteotomy in rhinoplasty at a level above or below the insertion of the inferior turbinate at the pyriform aperture. STUDY DESIGN: Controlled lateral osteotomies were performed in 16 cadaver noses. Eight of the lateral ostetomies were placed below (low) and eight were placed above (high) the insertion of the inferior turbinate. In all 16 noses medial osteotomies were performed. Dimensions of the nasal cavity were measured by acoustic rhinometry before and after the osteotomies. METHODS: The total minimum cross-sectional area (TMCA) and the cross-sectional area at the pyriform aperture (TCA-3.3) were calculated and the preoperative and postoperative values were analyzed statistically. RESULTS: There was no significant difference in the reduction of cross-sectional area in the group that underwent high lateral osteotomy compared with the group the underwent low lateral osteotomy. In both groups the TMCA was reduced, with 12% of the value (P = .001) before osteotomy, and the TCA-3.3 was reduced, with 15% of the value before osteotomy (P = .000). CONCLUSIONS: After lateral and medial ostetomies a significant decrease in the anterior dimensions of the nose is observed. The decrease following osteotomy does not seem to be due to the placement of the lateral osteotomy at the pyriform aperture but rather to the detachment of the bony vault from the surrounding structures.

Prediction of nasal obstruction based on clinical examination and acoustic rhinometry.

The aim of this study was to find variables which characterize nasal obstruction. Scores from the clinical history, anterior rhinoscopy and objective values from acoustic rhinometry were found of importance. In a randomly-selected adult population of 230 individuals, 14% had the subjective feeling of nasal obstruction. The variables of significant value to predict nasal obstruction were: (1) symptoms of hypersensitivity/allergy and infection; (2) anterior septal deviations; and (3) small anterior dimensions of the nasal cavity. A minimum cross-sectional area (MCA) equal to 0.50 cm2, a cross-sectional area at the piriform aperture of 0.70 cm2 and a large effect of decongestion at MCA were found to be the best variables to separate obstructed from normal noses. Also, differences between each side of the nose were found of predictive value. In conclusion, a nose at risk for nasal obstruction is one with symptoms of allergy, frequent infections, small dimensions anteriorly, large difference between both sides, and a large degree of swelling of the mucosa.

The nasal septum and the development of the midface. A longitudinal study of a pair of monozygotic twins.

The development of the nose and the growth of the midface has been followed in a pair of identical twins. One of them (twin A) had nasal septum destruction after septal haematoma and abscess at the age of 7 years, and was treated by immediate implantation of homologous septal cartilage from a tissue bank. From 7-17 years of age the growth and development of the nose and face were followed. Lateral cephalograms, photographs, acoustic rhinometry and rhinoscopy were performed. Twin B presented a normal nasal and facial growth and served as control. Twin A developed a saddle nose, an upward displacement of the anterior part of the maxilla, diminished vertical development of the nasal cavity, and a retrognathically positioned maxilla due to decreased anteroposterior maxillary growth. This case report seems to indicate that the cartilaginous nasal septum is an important factor influencing vertical and sagittal growth of the maxilla.

Bilateral inferior turbinoplasty in chronic nasal obstruction.

Bilateral inferior turbinoplasty was performed in cases of chronic nasal obstruction, in which conservative treatment had failed. Forty-five patients without significant septal deviation and with chronic nasal obstruction were objectively evaluated by acoustic rhinometry (AR) before and 3-6 months after turbinoplasty, in order to assess the changes of the dimensions of the nasal cavity obtained. Mucosal turbinate hypertrophy (defined objectively by AR) was present in 76% of the cases. Satisfactory subjective nasal patency was achieved in 93% of patients. Turbinoplasty resulted in an increase of 22% at the minimum cross-sectional area, 37% at the cross-sectional area 3.3 cm from the nostrils, and 47% at the cross-sectional area 4.0 cm from the nostrils. The increase was not related to the subjective result of the operation. Tendency to crusting and to vasomotor symptoms were related to unsatisfactory results. No crusting or bleeding were observed.

The parameters of care for cleft lip and palate patients in Aarhus, Denmark.

Aarhus Cleft Palate Institute receives approximately 75 new cleft patients a year. Due to statuary notification of all newborn cleft patients to the Institute, the treatment protocol can be offered to the family from right after birth, and a coordinated team approach can be established. The individually planned primary surgery, speech and growth of the maxillo-facial skeleton is followed by regular team examinations. Speech development is followed from the child is one year old in order to be able to provide speech assessment as soon as problems of hypernasality and articulation disorders or language delay is evident. One of the goals of speech assessment is to achieve acceptable speech as early as possible and at best before school start. Orthodontic treatment is usually started at 8 years of age, in UCLP and BCLP patients in combination with bonegrafting at 9-11 years of age. In patients with impaired growth of the maxilla, attention is paid to identify candidates for orthognathic surgical treatment as early as possible. All secondary surgical treatment on jaws, lips and nose are coordinated and usually the treatment can be finished by the late teens. The described team approach towards the parameters of care for cleft lip and palate patients has basically been used for more than 50 years. A systematic follow-up and data collection on all patients provide a scientific base for evaluation of treatment results. Based on long-term investigations the protocol has gradually been modified during time to improve the quality of patient care.

Spontaneous variations in congestion of the nasal mucosa.

BACKGROUND: Nasal patency shows spontaneous variations but is also influenced by exercise and allergic conditions. These variations have not been described in detail with regard to allergy. OBJECTIVES: The purpose of this study was to examine whether these variations are different in nonallergic subjects and in subjects with nasal allergy to pollen out of the pollen season. METHODS: We examined 12 of each type of subject in the winter on two days for seven hours in a climatic chamber with constant temperature and relative humidity, one day for examination of spontaneous variations and one day for examination of exercise response. Every 15 minutes the volume of the nasal cavities, minimum cross-sectional areas, and areas at fixed distances from the nostril were measured by acoustic rhinometry. Symptoms were scored by a questionnaire. RESULTS: There were more pronounced spontaneous variations expressed as the coefficient of variation of nasal volume in allergic than in nonallergic subjects (14% against 9%, P = .004). A nasal cycle was observed in four of the nonallergic subjects and three of the allergic subjects. In the postexercise period, the spontaneous variations in the nonallergic subjects were increased but decreased in the allergic subjects. Exercise increased nasal patency more in the allergic subjects but only significantly for the cross-sectional area at 3.3 cm (105% compared with 43% in the nonallergic subjects, P = .05). In contrast, pharmacologic decongestion in the allergic subjects showed a tendency to be more pronounced for the nasal cavity volume (55% increase versus 42%, P = .08). There was no difference between the groups in nasal symptom scores. CONCLUSION: Allergic subjects out of the pollen season have more congested and more sensitive nasal mucosa than nonallergic subjects.

Reduction rhinoplasty and nasal patency: change in the cross-sectional area of the nose evaluated by acoustic rhinometry.

The feeling of nasal patency is related to the dimensions of the nasal cavity. After aesthetic reduction rhinoplasty, the cross-sectional areas of the nose may decrease critically. In this study, acoustic rhinometry, a new method based on acoustic reflections, was used to evaluate the internal dimensions of the nasal cavity in 37 patients before reduction rhinoplasty and again 6 months after surgery. The internal dimensions of the nasal cavity--especially the anterior dimensions--were reduced after rhinoplasty. Compared with the preoperative values, the minimum cross-sectional area (at the nasal valve) decreased by 22% (totally) to 25% (unilaterally) (P = .000), and the cross-sectional areas at the piriform aperture decreased by 11% to 13% (P = .02).

Nasal histamine challenge in nonallergic and allergic subjects evaluated by acoustic rhinometry.

Nasal patency shows spontaneous variations but is influenced by a number of factors like exercise and allergic conditions. Nasal histamine challenge has been used to define nasal hypersensitivity. We have applied acoustic rhinometry as a new objective method to study the spontaneous variations of the nasal mucosa and its response to histamine challenge in 12 nonallergic subjects and 12 subjects with nasal allergy to pollen, but out of the pollen season. Measurements of the minimum cross-sectional area and the volume of the nasal cavities were done every 15 min for 6 h. More pronounced spontaneous variations, defined by the coefficient of variation of the measurements, were encountered in the allergic than in the nonallergic subjects, especially with regard to the minimum cross-sectional areas in the nasal cavities (P < 0.02). Allergic subjects showed increased sensitivity to histamine, as compared with nonallergic subjects, during low-concentration (0.1%) challenge (P < 0.05) and a prolonged effect of histamine challenge (P = 0.01). Antihistamine (cetirizine) had a significant effect on the histamine-induced symptoms and decrease of nasal dimensions during histamine challenge, but no significant effect on pollen-induced changes. In the allergic group, the decrease in minimum area during allergen provocation correlated with the level of specific IgE (r = 0.81; P = 0.0015).

Septoplasty and compensatory inferior turbinate hypertrophy: a randomized study evaluated by acoustic rhinometry.

The present study deals with the indication for inferior turbinate surgery in cases of concomitant anterior septal deviation. We define, by acoustic rhinometry, the characteristics of the obstructed nose and define mucosal turbinate hypertrophy. A random sample of 80 patients with nasal obstruction and anteriorly located septal deviation were objectively evaluated by acoustic rhinometry pre- and post-operatively. All had septoplasty and half were randomly selected to have anterior inferior turbinoplasty performed in the side opposite to the major septal deviation. Severe septal deviation, expressed by a minimal cross-sectional area less than 0.4 cm2 was present in 37 patients. In this group inferior turbinate reduction seems advisable. In the wide side, the minimal cross-sectional area and the cross-sectional areas at 3.3 and 4.0 cm from the nostrils increased in the turbinectomy group and decreased in the non-turbinectomy group after correction of the septal deviation. In the group with less pronounced septal deviation no influence of turbinate reduction could be detected.

Nasal packing after septoplasty.

A prospective study to compare 3 different types of nasal pack after septoplasty with or without a supplementary turbinectomy has been performed with respect to discomfort and complications caused by the packing and the short-term results evaluated 3 months after operation. Fingerstall packings gave less problems than either Merocel or hydrocortisone-terramycine gauze packs with ventilation tubes. They were easier to remove and were associated with less persistent secretion in the post-operative period. No definite advantage from the patient's point of view has been demonstrated by the use of tubes and nasal packing. An analysis of the nasal patency 3 months post-operatively by peak-flow index and acoustic rhinometry revealed no differences between groups.

The nasal septum in relation to the development of the nasomaxillary complex: a study in identical twins.

The influence of the nasal septum and respiration, evaluated by the total nasal resistance (TR) on the development of the nasomaxillary complex, was studied in 42 identical twins. An understanding of this influence is important for a determination of whether surgery involving the nose should be performed in children. Comparison within and between twins with different septal deformities indicated that the cartilaginous nasal septum influences the development of the nose and the anteroposterior dimensions of the maxilla. Anterior septal deformities resulted in underdeveloped cartilaginous noses and a shorter anteroposterior dimension for the maxilla. No relation was found with regard to posterior septal deformities, which may be considered as part of the development of the midface. Vertical dimensions of the face were related to TR. Increased values of TR were significantly related to a shorter maxillary height. This may not express a causal relationship but rather genetically determined shorter facial dimensions.

Acoustic rhinometry: values from adults with subjective normal nasal patency.

The nose with normal feeling of nasal patency, and no gross structural changes has been described in 82 individuals by acoustic rhinometry. Curves for one and both sides of the nasal cavity and before and after decongestion have been recorded. We have found that the minimal cross-sectional area (MCA) is located anteriorly in the nasal cavity; in some subjects it is localized at the head of the inferior turbinate and in other subjects more anteriorly at the nasal valve. After decongestion MCA moves even more anteriorly. Beyond the MCA the dimension of the nasal cavity increases, with maximal effect of decongestion at 4 cm from nostrils. Decongestion increases the total volume of the nasal cavity by 35%.

Turbinate hypertrophy. Evaluation of the nasal cavity by acoustic rhinometry.

We used acoustic rhinometry to assess the geometry of the nasal cavity. The cross-sectional area of the nasal cavity as a function of distance from the nostrils was obtained. Seventeen patients with hypertrophy of the inferior turbinate and septal deviations were examined preoperatively and postoperatively; 34 normal subjects served as controls. The cross-sectional area at the anterior part of the nose suggested that skeletal hypertrophy of the inferior turbinate might be expected in the side opposite the main septal deviation. Unilateral inferior turbinoplasty seems advisable.

Acoustic rhinometry: evaluation of the nasal cavity with septal deviations, before and after septoplasty.

We introduce acoustic rhinometry as a new, objective method to assess the geometry of the nasal cavity. The cross-sectional area of the nasal cavity as a function of distance from the nostrils was obtained. A group of 21 patients with septal deformities was examined with acoustic rhinometry preoperatively and postoperatively. These values were compared with those of 21 normal control subjects. The minimal cross-sectional area (MCA) is located in the anterior part of the nose, and it shifts anteriorly under the effect of decongestion. The preoperative value of MCA is related to the location and severity of the anterior septal deformity. Postoperative smaller MCA found in the opposite side of that narrowed by a severe anterior septal deformity may be explained by the impact of septoplasty without reduction of a hypertrophic turbinate. A highly significant relation between MCA and the subjective feeling of nasal patency, before and after surgery, suggests that MCA is a valuable parameter to express nasal patency. Correction of posterior septal deformities is found to increase significantly the cross-sectional area posteriorly. The effect of decongestion in the postoperative values, however, suggests that the mucosa contributes even more to the cross-sectional area of the posterior part of the nose. Acoustic rhinometry seems very suitable for evaluation of the nasal cavity in cases where septoplasty and turbinoplasty is considered, as well as for the postoperative evaluation.