The relationship between nasal cross-sectional area and nasal air volume in normal and nasally impaired adults

Volumetric nasal cavity analysis in children with unilateral and bilateral cleft lip and palate

OBJECTIVES/HYPOTHESIS

Children with cleft lip and palate (CLP) often suffer from nasal obstruction that may be related to effects on nasal volume. The objective of this study was to compare side:side volume ratios and nasal volume in patients with unilateral (UCLP) and bilateral (BCLP) clefts with age-matched controls.

STUDY DESIGN

Retrospective case-control study using three-dimensional (3D) nasal airway reconstructions.

METHODS

We analyzed 20 subjects (age range = 7-12 years) with UCLP and BCLP from a regional craniofacial center who underwent cone beam computed tomography (CT) prior to alveolar grafting. Ten multislice CT images from age-matched controls were also analyzed. Mimics software (Materialise, Plymouth, MI) was used to create 3D reconstructions of the main nasal cavity and compute total and side-specific nasal volumes. Subjects imaged during active nasal cycling phases were excluded.

RESULTS

There was no statistically significant difference in affected:unaffected side volume ratios in UCLP (P = .48) or left:right ratios in BCLP (P = .25) when compared to left:right ratios in controls. Mean overall nasal volumes were 9,932 ± 1,807, 7,097 ± 2,596, and 6,715 ± 2,115 mm(3) for control, UCLP, and BCLP patients, respectively, with statistically significant volume decreases for both UCLP and BCLP subjects from controls (P < .05).

CONCLUSIONS

This is the first study to analyze total nasal volumes in BCLP patients. Overall nasal volume is compromised in UCLP and BCLP by approximately 30%. Additionally, our finding of no major difference in side:side ratios in UCLP and BCLP compared to controls conflicts with pre-existing literature, likely due to exclusion of actively cycling scans and our measurement of the functional nasal cavity.

LEVEL OF EVIDENCE

3b. Laryngoscope, 126:1475-1480, 2016.

Efficiency of external nasal dilators in pediatric nasal septal deviation

INRODUCTION

Nasal septal deviation results from irregular development of the nasomaxillary complex and trauma. Treatment of nasal septal deviation in pediatric patients is one of the biggest challenges in rhinology. Surgery may alter craniofacial growth patterns, and so it may be indicated only in the selected cases. The use of external nasal dilators is a relatively new treatment modality in nasal obstruction.

OBJECTIVE

This study was performed to assess the efficacy of external nasal dilator in pediatric nasal septal deviation patients.

METHODS

Seventy-six children who were diagnosed with nasal septal deviation at our outpatient clinic were included in the study. The patients were divided into 2 groups: the external nasal dilator group was composed of 48 children that had used an external nasal dilator for at least 1 month and still been using, while the control group was comprised of 28 children that had not received any treatment and had not used an external nasal dilator. The parents of the children were asked to complete the obstructive sleep apnea 18 questionnaire. In addition, the external nasal dilator group was asked to complete the questionnaire after stopping external nasal dilator use for 2 weeks and the control group also repeated the obstructive sleep apnea 18 questionnaire.

RESULTS

The obstructive sleep apnea 18 questionnaire results were significantly different between the external nasal dilator group and the control group at the beginning of the study (i.e., when patients in the external nasal dilator group were still using their dilators, P = 0.000). On the other hand, there was no difference between the 2 groups after the patients in the external nasal dilator group had stopped using their external nasal dilator (P = 0.670).

CONCLUSION

External nasal dilator use relieved nasal septal deviation, which narrows the nasal valve. The results of this study suggest that external nasal dilator could be used in patients that are not candidates for septoplasty.

Three-dimensional computed tomographic analysis of changes to the external features of the nose after surgically assisted rapid maxillary expansion and orthodontic treatment: a prospective longitudinal study

INTRODUCTION

The aim of this prospective, longitudinal study was to evaluate changes to the external shape and form of the nose after surgically assisted rapid maxillary expansion and orthodontic treatment. The changes were registered using a 3-dimensional computer tomography technique, based on superimposition on the anterior base of the skull.

METHODS

The subjects comprised 35 patients (mean age, 19.7 years; range, 16.1-43.9 years). Low-dose, helical computerized tomography images were taken at treatment start and after orthodontic treatment, about 18 months postsurgery. The 3-dimensional models were registered and superimposed on the anterior cranial base.

RESULTS

There were in general significant widening and overall anterior and inferior displacement of the nasal soft tissues. The changes varied in size and direction. No correlation was found between the initial and final widths of the nose, or between the initial and final widths of the nostrils.

CONCLUSIONS

After surgically assisted rapid maxillary expansion, the most obvious changes to the external features of the nose were at the most lateral alar bases. The difference in lateral displacement profoundly influenced the perception of a more rounded nose. Patients with narrow and constrained nostrils can benefit from these changes. The 3-dimensional superimposition applied in this study is a reliable method, circumventing projection and measurement errors.

Mandibular incisor extraction: a systematic review of an uncommon extraction choice in orthodontic treatment

OBJECTIVES

To review the published literature in order to address clinical questions regarding the indications, effects and outcomes of mandibular incisor extraction in orthodontics.

DATA SOURCES

Three electronic databases were searched: PubMed (1950-January 2011), Ovid Embase+Ovid Embase Classic (1947-January 2011) and Cochrane library (6 Cochrane databases, 1996-January 2011). The following journals were additionally searched: American Journal of Orthodontics and Dentofacial Orthopedics (1960-January 2011), Angle Orthodontist (1960-January 2011), European Journal of Orthodontics (1970-January 2011) and Journal of Orthodontics (1974-January 2011). Grey literature was searched using Google Scholar and System for Information on Grey Literature in Europe. Secondary search of the references cited in the relevant articles was also conducted.

DATA SELECTION

Articles in vivo, in Humans, in English, concerning treatment of malocclusion with mandibular incisor extractions or missing mandibular incisors. Fifty-four publications met these inclusion criteria and were reviewed.

DATA EXTRACTION

Data were extracted independently by two reviewers with regard to: (1) indications; (2) contraindications; (3) effects; (4) outcomes; and (5) factors associated with successful outcomes.

DATA SYNTHESIS

Considering the descriptive nature of the studies found, a narrative synthesis was undertaken.

CONCLUSIONS

The descriptive nature of published articles precludes making strong evidence-based recommendations regarding this extraction choice, but it is clear that mandibular incisor extraction can be effectively used in the resolution of crowding, as well as intermaxillary malocclusion in carefully selected cases. Several factors that could lead to good outcomes of orthodontic treatment following mandibular incisor extraction were identified. Mild-to-moderate class III malocclusion, an edge-to-edge anterior occlusion or anterior crossbite, with mild anterior mandibular tooth size excess, and minimal open bite tendencies were the clinical situations most frequently treated with this unique extraction choice. On the other hand, clinicians should be careful to avoid poor outcomes such as gingival recession, open interproximal gingival embrasures, increased overjet and overbite.

Nasal cavity size, airway resistance, and subjective sensation after surgically assisted rapid maxillary expansion: a prospective longitudinal study

INTRODUCTION

The aims of this study were to measure changes in nasal minimum cross-sectional area and nasal airway resistance after surgically assisted rapid maxillary expansion and to explore a possible correlation with the subjective sensation of nasal obstruction.

METHODS

Minimum cross-sectional area and nasal airway resistance were measured in 39 consecutive patients treated with surgically assisted rapid maxillary expansion. Subjective nasal obstruction was assessed by a questionnaire at pretreatment and at 3 and 18 months postoperatively.

RESULTS

Subjective nasal obstruction had improved significantly by 3 months postoperatively. Minimum cross-sectional area increased and nasal airway resistance decreased. No correlations were found. In subjects with pretreatment subjective nasal obstruction and initially narrow anterior minimum cross-sectional area, there was a significant correlation between a moderate increase in anterior minimum cross-sectional area and improvement in perceived nasal obstruction. Eighteen months postoperatively, no changes were found from pretreatment values for subjective nasal obstruction, minimal cross-sectional area, or nasal airway resistance, and there were no correlations. Subjects with a sensation of nasal obstruction at treatment start reported a lasting significant subjective improvement.

CONCLUSIONS

The postoperative effects of surgically assisted rapid maxillary expansion did not persist in the long term. No correlation was found between objective and subjective findings. Subjects with pretreatment nasal obstruction, however, reported a lasting sensation of improved nasal function after surgically assisted rapid maxillary expansion.

A theoretical cause of nasal obstruction in patients with repaired cleft palate

BACKGROUND

During cleft palate repair, mucoperiosteal flaps are elevated from the palatal shelves and the nasal septum to accomplish tension-free closure of the nasal floor. This study was designed to geometrically describe how palate repair inherently limits airflow by decreasing nasal cavity cross-sectional area and increasing nasal airflow resistance. In addition, this study investigates whether the width of the repaired cleft palate directly affects the degree of postoperative airflow resistance.

METHODS

A simplified geometric model of normal nasal cavity anatomy was compared with an equivalent schematic representing an individual with an unrepaired palatal cleft. Mathematical equations approximating the cross-sectional areas of normal and cleft nasal cavities were created. The theoretical postoperative loss of nasal cavity cross-sectional area was then considered for both unilateral and bilateral palatal clefts.

RESULTS

According to this geometric model, the cross-sectional area of the nasal cavity is decreased in patients who undergo cleft repair. Repaired bilateral clefts experience a greater area loss than their unilateral counterparts.

CONCLUSION

Nasal cavity resistance is higher in patients who have undergone cleft repair than in individuals who have not undergone cleft repair. because tension-free closure of the nasal floor inherently reduces cross-sectional breathing area. The wider the cleft, the higher the resistance to nasal airflow postoperatively. This iatrogenic source of nasal resistance is likely additive to other anatomic contributors to airflow resistance observed in individuals with cleft nasal deformities.

Avaliação do efeito da expansão rápida da maxila no padrão respiratório, por meio da rinomanometria anterior ativa: descrição da técnica e relato de caso

A finalidade deste artigo é avaliar o efeito da expansão rápida da maxila (ERM) no padrão respiratório. Por intermédio de um caso clínico, será relatado como indivíduos com atresia da maxila e problemas respiratórios podem se beneficiar com a expansão rápida da maxila. Outro aspecto que deve-se salientar é como profissionais da área da saúde, principalmente ortodontistas e otorrinolaringologistas, têm à sua disposição exames complementares para o diagnóstico do paciente com "Respiração Bucal"

Rhinometric evaluation of nasal cavity geometry and its relation to the upper arch transverse distance

The objective of this study was to evaluate children's respiratory patterns in the mixed dentition, by means of acoustic rhinometry, and its relation to the upper arch width development. Fifty patients were examined, 25 females and 25 males with mean age of eight years and seven months. All of them were submitted to acoustic rhinometry and upper and lower arch impressions to obtain plaster models. The upper arch analysis was accomplished by measuring the interdental transverse distance of the upper teeth, deciduous canines (measurement 1), deciduous first molars (measurement 2), deciduous second molars (measurement 3) and the first molars (measurement 4). The results showed that an increased left nasal cavity area in females means an increased interdental distance of the deciduous first molars and deciduous second molars and an increased interdental distance of the deciduous canines, deciduous first and second molars in males. It was concluded that there is a correlation between the nasal cavity area and the upper arch transverse distance in the anterior and mid maxillary regions for both genders.

Avaliação do espaço aéreo faríngeo por meio da tomografia computadorizada de feixe cônico

INTRODUÇÃO: a avaliação do espaço aéreo superior faz parte da rotina na elaboração do diagnóstico e plano de tratamento ortodôntico. A radiografia cefalométrica em norma lateral tem sido usada rotineiramente na avaliação da permeabilidade do espaço aéreo, esbarrando na limitação de fornecer uma imagem bidimensional de uma estrutura tridimensional. A Tomografia Computadorizada de Feixe Cônico (TCFC) tem entrado na realidade ortodôntica trazendo um arsenal de informações concernentes ao espaço aéreo superior. Por fornecer uma imagem tridimensional, possibilita determinar de maneira precisa a área de maior estreitamento da faringe, que ofereceria maior resistência à passagem aérea. OBJETIVOS: o propósito deste artigo é esclarecer o ortodontista quanto aos recursos disponíveis na TCFC para o diagnóstico de possíveis barreiras físicas que possam diminuir a permeabilidade das vias aéreas superiores.

Estudo cefalométrico comparativo dos espaços naso e bucofaríngeo nas más oclusões Classe I e Classe II, Divisão 1, sem tratamento ortodôntico, com diferentes padrões de crescimento

A finalidade deste estudo foi comparar os espaços aéreos naso e bucofaríngeo em indivíduos com má oclusão Classe I e Classe II, divisão 1, segundo Angle, do gênero masculino e feminino, com idade média de 11 anos e 6 meses, com padrão de crescimento normal e vertical, não tratados ortodonticamente. A amostra desse estudo foi dividida em dois grupos: 40 pacientes apresentando Classe I e 40 pacientes com Classe II, divisão 1, cada grupo subdividido de acordo com o padrão de crescimento facial: normal e vertical. Os espaços aéreos naso e bucofaríngeo foram avaliados segundo a análise de McNamara Jr., pelas medidas NFa-NFp e BFa-BFp. A análise dos resultados obtidos revelou que, a medida do espaço bucofaríngeo para Classe I com padrão de crescimento vertical e para o espaço nasofaríngeo para Classe II com padrão normal de crescimento apresentaram-se semelhantes à medida padrão da amostra de McNamara Jr.. As outras medidas apresentaram-se estatisticamente menores. Na comparação entre os grupos, o espaço nasofaríngeo no grupo Classe I com padrão de crescimento vertical, apresentou-se menor do que nos grupos Classe I e grupo Classe II divisão 1, ambos com padrão de crescimento normal. O espaço bucofaríngeo não sofreu alteração significante de um grupo para outro. Em relação à hipertrofia da tonsila faringeana, apenas o grupo Classe I com padrão de crescimento vertical apresentou obstrução; para hipertrofia das tonsilas palatinas, apenas o grupo Classe I com padrão de crescimento vertical e Classe II com padrão de crescimento normal apresentou hipertrofia das tonsilas palatinas.

A modification of the pressure-flow technique for measuring breathing of cold air and its effect on nasal cross-sectional area

The purpose of this article was to develop a method based on the pressure-flow technique for measuring cold air breathing and to observe the immediate reactions of breathing function to cold air inhalation in 40 subjectively healthy adults. The pressure-flow technique was used to measure airflow rate and oral/nasal pressure and to calculate the smallest cross-sectional area of the nasal airway. The equipment was modified to allow measurements both at room temperature and with cooled air by connecting the nasal mask to a freezer with a two-valve cylinder and tubing. Nasal cross-sectional area showed a significant decrease from 42.3 mm2 at room temperature to 37.6 mm2 with cooled air. Correspondingly, the airflow rate changed from 411 ml/s to 369 ml/s, whereas the differential pressure remained about the same, 1.2 and 1.3 cm H2O, respectively. The interindividual variation was fairly large. The results suggest that the breathing of cold air seems to cause changes in nasal cross-sectional area and airflow rate. In general, the cross-sectional area diminishes, the change being quantitatively more pronounced in subjects with an initially large area.

Nasal airway in breathing and speech

Clefts of the lip and palate frequently produce nasal deformities that tend to reduce the size of the nasal airway. Approximately 70% of the cleft population have nasal airway impairment and about 80% "mouth-breathe" to some extent. Surgical correction of nasal, palatal, and pharyngeal structures may further compromise breathing. Type of cleft appears to affect airway size, with unilateral clefts demonstrating the smallest airway. Although a pharyngeal flap may further decrease airway size, some individuals do not notice a postoperative change because of airway compromise prior to flap placement. Speech is a modified breathing behavior that uses the respiratory system to provide an energy source and involves structures within the respiratory tract to modulate this energy into meaningful sounds. The oral, nasal, and pharyngeal structures that are affected by cleft lip and palate during breathing are often compromised for speech as well. The nasal airway plays an important role in controlling speech pressures when velopharyngeal function is impaired. A "good" nose for breathing is often a "bad" nose for speech under such circumstances.

Is nasal airway size a marker for susceptibility toward clefting?

Johnston and Hunter (1989) reported that in monozygotic twins discordant for cleft lip +/- palate, the noncleft twins demonstrated what appeared to be a bimodal distribution of nasal cavity width. Two thirds showed reduced airway size and one third showed normal or slightly greater airway size. They suggested that the two-thirds group may represent reduced size of the medial nasal prominences and the other may represent underdevelopment of the maxillary prominence. We were particularly interested in the findings because the difference in distribution may represent differences in pathogenesis and therefore have etiologic significance. With this in mind we assessed nasal cross-sectional areas in 37 subjects with cleft lip or cleft lip +/- palate using the pressure-flow technique during breathing. A group of 72 noncleft individuals served as controls. As expected, the data revealed that subjects with clefts had a significantly reduced nasal airway (p = .0001). More important, the distribution of nasal airway size in the cleft group was similar to that reported by Johnston and Hunter (1989). This comparability suggests that it may be possible to assign most cleft lip +/- palate patients to a particular group. Since heredity may differ among the two groups (Chung et al., 1986), we may have a simple technique to assess the risk of occurrence for cleft lip +/- palate.

Mandibular and maxillary growth after changed mode of breathing

The amount of maxillary and mandibular growth and the direction of maxillary growth were studied in 38 children during the 5 years after adenoidectomy for correction of severe nasopharyngeal obstruction. The amount of mandibular growth measured between successive gnathion points on superimposed radiographs was significantly greater in the group who had an adenoidectomy than in the matched controls. In the boys the difference was 3.8 mm (p less than 0.001), and in the girls the difference was 2.5 mm (p less than 0.01). The boys also showed a tendency toward greater growth in the maxilla as measured between successive subnasal points (1.2 mm, p less than 0.05). We detected no difference in the direction of maxillary growth between who had undergone adenoidectomy and the controls.

Nasal airway impairment: the oral response in cleft palate patients

The purpose of this study was to assess the oral response to severe nasal airway impairment in patients with cleft palate. Inductive plethysmography was used to measure the percent of nasal breathing, and the pressure-flow technique was used to estimate nasal area in 15 persons with severe nasal airway impairment. Mean nasal area was 0.17 cm2, and the average percent of nasal breathing was 20%. Analysis revealed a strong correlation (0.87) between nasal size and percent of nasal breathing in this selected group. Modeling studies based on the mean values from the subjects' data indicated that the model "mouth" would have to open 0.5 cm2 to shunt 80% of the airflow orally, an amount equivalent to the mean value of the subjects' respiratory mode. More important, the extrapolated data revealed that upper-airway resistance decreased in the model from 8.7 cm H2O/L/sec to a level of 3.2 cm H2O/L/sec, which is an average value for healthy adults. These data support the concept that the mouth acts as a variable resistor to maintain an optimal respiratory tract resistance when the nasal airway is impaired.

The effect of cleft palate speech aid prostheses on the nasopharyngeal airway and breathing

This study determined the effect of a speech aid prosthesis on resting breathing. Nasal cross-sectional area was measured during inspiration and expiration in eight cleft palate patients. The measurements were made for the unobturated defect during both phases of respiration and then repeated while the defect was obturated by a speech aid prosthesis. The results of the study revealed that the presence of a speech aid prosthesis significantly decreased the cross-sectional region of the nasal airway. In 50% of the subjects, the cross-sectional region was less than 0.40 cm2 with concomitant impairment in nasal respiration when the speech aid prosthesis was present in the oral cavity. The data suggest that the design of these prostheses should account for breathing requirements as well as for speech.

Normal nasal airway resistance in noses of different sizes and shapes

Measurement of nasal airway resistance is becoming a common clinical technique. Accurate definition of the normal range of airflow is critical for maximal usefulness of this technique. Since typical nasal size and shape vary greatly with ethnic background, different norms for different ethnic groups may be appropriate. Nasal airway flow and resistance and external nasal size and shape were measured in 130 asymptomatic subjects (52 black, 56 white, and 22 Hispanic). Nasal length, width, columellar length, and nasolabial angle were similar for whites and Hispanics, but both groups differed significantly from blacks--even when changes attributable to biologic aging were factored out. In spite of these differences, there was no significant difference in any nasal airflow or resistance parameter among groups, suggesting that currently used airflow and resistance standards are valid for these three different ethnic groups.

External nasal morphology and respiratory function

Clinicians have been known to characterize nasal respiratory function on the basis of subjective appraisal of external facial morphology. Certain nasal morphologic features have been assumed to be associated with impaired nasal function. The purpose of this study was to develop measures of anterior external nasal morphology and to determine whether any of these measures correlate with nasal function. Nasal casts were produced from impressions of 60 postpubertal white subjects from which four measures were made to characterize nasal morphology: (1) nasal base shape, (2) minimum nasal orifice width, (3) nasal orifice shape, and (4) nasal orifice area. Nasal function was evaluated by measuring nasal airway resistance by means of posterior rhinomanometry and by measuring the air respired nasally and orally by means of the simultaneous nasal and oral respirometric technique. No significant correlations were found between external nasal morphology and nasorespiratory function. These findings underscore the necessity of avoiding assumptions about breathing function on the basis of clinical appraisal of external nasal form.

Relationships of changes in craniofacial morphology, head posture, and nasopharyngeal airway size following mandibular osteotomy

The aim of the present study was to illustrate a possible relationship between changes in craniofacial morphology after mandibular osteotomy and changes in head posture and nasopharyngeal airway size. The material comprised standardized profile cephalograms of 52 patients with mandibular prognathism, all of whom underwent orthodontic adjustment before mandibular osteotomy. Mean age of the patients was 24.3 years; 12 men and 40 women participated in the study. The first profile radiograph of each patient was taken 1 day before surgical treatment in the natural head (mirror) position. All patients underwent mandibular surgery with a bilateral vertical ramus osteotomy. The cephalometric investigation was repeated approximately 1 year after the surgical procedure (means = 1.12 years). Craniofacial morphology was evaluated by 12 parameters describing sagittal and vertical jaw relationship. Head posture was evaluated by the craniocervical angulation and airway as nasopharyngeal airway size. Pearson's correlation analysis was used to evaluate the relationship between morphology, posture, and airway size before surgery and changes in these parameters after surgery. Before surgical treatment statistically significant correlations were found between posture and many morphologic variables, mostly mandibular. Small correlations were observed between posture and airway size, and airway size and morphology. After the surgical procedure, changes in posture were still related to changes in mandibular morphology, while other correlations between posture and morphology had been eliminated. Changes in nasopharyngeal airway size were not correlated to any changes in morphology, apart from maxillary prognathism, nor to changes in posture. The results indicated that mandibular morphology and function play a significant role in determining head posture.

The relationship between nasal airway size and nasal-oral breathing

Most clinicians agree that impaired nasal breathing results in obligatory mouth breathing. Some believe that mouth breathing influences dentofacial growth; others disagree. The term mouth breathing is confusing because total mouth breathing rarely occurs. A combination of nasal and oral breathing is more usual. The purpose of the present study involving 116 adult subjects was to (1) assess the relationship between nasal impairment and nasal-oral breathing, (2) determine the switching range from nasal to nasal-oral breathing, and (3) quantify the term mouth breathing. The pressure-flow technique was used to estimate nasal airway size; inductive plethysmography was used to assess nasal-oral breathing in normal and impaired breathers. Analysis of the date showed a Pearson rank correlation of 0.545 (P less than 0.001) between nasal area and nasal-oral respiration. Ninety-seven percent of subjects with a nasal size less than 0.4 cm2 were mouth breathers to some extent. About 12% of subjects with an adequate airway were assumed to be habitual mouth breathers. The findings indicate that the switching range from nasal to nasal-oral breathing is very narrow (0.4-0.45 cm2). These results also confirm our contention that in adults an airway less than 0.4 cm2 is impaired.