Developmental changes in collapsibility of the passive pharynx during infancy

Critical to Know Pcrit: A Review on Pharyngeal Critical Closing Pressure in Obstructive Sleep Apnea

It is crucial to understand the underlying pathophysiology of obstructive sleep apnea (OSA). Upper airway collapsibility is an important pathophysiological factor that affects the upper airway in OSA. The aim of the current study was to review the existing body of knowledge on the pharyngeal collapsibility in OSA. After a thorough search through Medline, PubMed, Scopus, and Web of science, the relevant articles were found and used in this study. Critical closing pressure (Pcrit) is the gold standard measure for the degree of collapsibility of the pharyngeal airway. Various physiological factors and treatments affect upper airway collapsibility. Recently, it has been shown that the baseline value of Pcrit is helpful in the upfront selection of therapy options. The standard techniques to measure Pcrit are labor-intensive and time-consuming. Therefore, despite the importance of Pcrit, it is not routinely measured in clinical practice. New emerging surrogates, such as finite element (FE) modeling or the use of peak inspiratory flow measurements during a routine overnight polysomnography, may enable clinicians to have an estimate of the pharyngeal collapsibility. However, validation of these techniques is needed.

Pharyngomalacia diagnosed by laryngo-tracheo-bronchoscopy in the neonatal intensive care unit

BACKGROUND

Flexible fiber-optic laryngo-tracheo-bronchoscopy has become widely performed in infants and neonates since the introduction of thin flexible fiberscopes. Laryngomalacia is the most common airway disease in infants causing stridor. Pharyngomalacia, termed pharyngeal occlusion during inspiration, was the second most common airway disease found in our hospital in patients that underwent laryngo-tracheo-bronchoscopy, but the incidence, patient characteristics, and natural course have not been reported in large numbers in Japan.

METHODS

A retrospective review was performed of medical records on patients admitted to our neonatal intensive care unit during the neonatal period diagnosed with pharyngomalacia between April 2009 and November 2018. Patient characteristics, concurrent airway diseases, comorbidities, and treatment were reviewed.

RESULTS

Forty-eight patients were diagnosed with pharyngomalacia. The median gestational age was 37.1 weeks, and the median birthweight was 2,552 g. Patients were diagnosed at a median age of 29 days, and cure was achieved at a median age of 4 months. Twenty-eight patients had concurrent airway diseases, laryngomalacia being the most common. Continuous positive airway pressure or high flow nasal cannula was used in 34 patients.

CONCLUSIONS

In patients with pharyngomalacia, half were born preterm, and more than half had concurrent airway diseases. The onset and diagnosis were made within the first month of life in more than half of the patients, and resolution was seen mostly within the first 6 months of life. Whenever a patient is suspected of having an airway disease, the pharyngeal space should be carefully observed to diagnose pharyngomalacia.

The maturation changes of sleep-related respiratory abnormalities in infants with laryngomalacia

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) and central sleep apnea (CSA) are common in infants with laryngomalacia. The purpose of this study was to evaluate developmental changes in sleep-related breathing disorders over time in infants with laryngomalacia and understand the effect of supraglottoplasty (SGP) and nonsurgical treatment.

METHODS

This is a retrospective review of infants with laryngomalacia who had at least 2 diagnostic polysomnography studies performed from January 2000 and May 2015. We included infants who had either OSA or CSA. Comparison of sleep and respiratory parameters by age group (0-6, 6-12, and >12 months old) was performed in both SGP and non-SGP groups using a mixed-effect regression model. A log-normal mixed model was used to explore the changes in sleep and respiratory parameters with age. The time to resolution of CSA and OSA was analyzed using nonparametric survival analysis.

RESULTS

A total of 102 infants were included; 57 had only OSA and 45 had both CSA and OSA. There were significant decreases in apnea-hypopnea index, obstructive index, central apnea index, and arousal index with increasing age in both SGP and non-SGP groups. The mean age at resolution of CSA (central apnea index < 5) was 7.60 months old for SGP and 12.57 months old for non-SGP (P < .05). There were no significant differences in the mean age at resolution of OSA (obstructive index < 1; 35.18 [SGP] vs 41.55 months [non-SGP]; P = .60) between SGP and non-SGP groups. Infants with neurologic disease, congenital anomalies, or genetic syndromes required significantly more time to resolve OSA (28.12 [normal] vs 53.13 [neurological] vs 59.53 months [congenital anomalies and genetic]; P < .01).

CONCLUSIONS

Both OSA and CSA improve in infants with laryngomalacia with increasing age regardless of SGP. The mechanism underlying these changes may involve airway growth and maturation of respiratory control. Time to resolution of OSA is affected by the presence of neurologic diseases, congenital anomalies, and genetic syndromes. Further studies are needed to confirm these findings and to evaluate long-term outcomes in this population.

Narcolepsy with cataplexy: Does age at diagnosis change the clinical picture?

Objective

To compare symptoms and sleep characteristics in patients diagnosed with narcolepsy‐cataplexy (NC) before and after the age of 18 years.

Methods

De novo patients with NC diagnosis completed a standardized questionnaire and interview, followed by a sleep study. The clinical and sleep measures were compared between patients diagnosed before (46 children, median age: 12 year old) and after (46 adults, median age: 28.5 year old) 18 years of age.

Results

The frequency of obesity (54% vs 17%), night eating (29% vs 7%), parasomnia (89% vs 43%), sleep talking (80% vs 34%), and sleep drunkenness (69% vs 24%) were higher in children than in adults, the frequency of sleep paralysis was lower (20% vs 55%) but the frequency of cataplexy and the severity of sleepiness were not different. Children scored higher than adults at the attention‐deficit/hyperactivity disorder (ADHD) scale. Depressive feelings affected not differently children (24%) and adults (32%). However, adults had lower quality of life than children. There was no difference between groups for insomnia and fatigue scores. Quality of life was essentially impacted by depressive feelings in both children and adults. Obstructive apnea‐hypopnea index (OAHI) was lower in children with higher mean and minimal oxygen saturation than in adults. No between‐group differences were found at the multiple sleep latency test. The body mass index (z‐score) was correlated with OAHI (r = .32).

Conclusion

At time of NC diagnosis, children have more frequent obesity, night eating, parasomnia, sleep talking, drunkenness, and ADHD symptoms than adults, even if sleepiness and cataplexy do not differ. These differences should be considered to ensure a prompt diagnosis.

Optimizing expiratory flows during mechanical cough in a pediatric neuromuscular lung model

Mechanical insufflation-exsufflation (MI-E) is recommended for subjects of all ages with neuromuscular disorders (NMDs) and weak cough. There is a lack of knowledge on the optimal treatment settings for young children. This study aims to determine the MI-E settings providing high expiratory airflow while using safe inspiratory volumes, and to identify possible limits where the benefit of incrementing the MI-E settings to achieve a higher expiratory airflow, decreased. Using an MI-E device and a lung model imitating a 1-year-old child with NMD, we explored the impact of 120 combinations of MI-E pressure and time settings on maximal expiratory airflow and inspiratory volume. High expiratory airflows were achieved with several pressure and time combinations where the exsufflation pressure, followed by insufflation pressure and time, had the greatest impact. The benefit of incrementing the settings to increase the expiratory airflow leveled off for the insufflation pressure and time, but not for the exsufflation pressure. Given exsufflation pressure of -40 or -50 cmH₂ O and insufflation time longer than 1 second, a plateau in the expiratory airflow curve was present at insufflation pressures from 25 cmH₂ O, whereas a plateau in the inspired volume curve occurred at insufflation pressures from 35 cmH₂ O. The present neuromuscular pediatric lung model study showed that expiratory pressure impacts expiratory airflow more than inspiratory pressure and time. An inspiratory and expiratory pressure set between 20 to 30 and -40 cmH₂ O, respectively, and an inspiratory time longer than 1 second may be considered as a basis when titrating MI-E settings in young children with NMD. The findings must be confirmed in clinical trials.

Sleep-disordered breathing and comorbidities: role of the upper airway and craniofacial skeleton

Obstructive sleep-disordered breathing (SDB), which includes primary snoring through to obstructive sleep apnea syndrome (OSAS), may cause compromise of respiratory gas exchange during sleep, related to transient upper airway narrowing disrupting ventilation, and causing oxyhemoglobin desaturation and poor sleep quality. SDB is common in chronic disorders and has significant implications for health. With prevalence rates globally increasing, this condition is causing a substantial burden on health care costs. Certain populations, including people with sickle cell disease (SCD), exhibit a greater prevalence of OSAS. A review of the literature provides the available normal polysomnography and oximetry data for reference and documents the structural upper airway differences between those with and without OSAS, as well as between ethnicities and disease states. There may be differences in craniofacial development due to atypical growth trajectories or extramedullary hematopoiesis in anemias such as SCD. Studies involving MRI of the upper airway illustrated that OSAS populations tend to have a greater amount of lymphoid tissue, smaller airways, and smaller lower facial skeletons from measurements of the mandible and linear mental spine to clivus. Understanding the potential relationship between these anatomical landmarks and OSAS could help to stratify treatments, guiding choice towards those which most effectively resolve the obstruction. OSAS is relatively common in SCD populations, with hypoxia as a key manifestation, and sequelae including increased risk of stroke. Combatting any structural defects with appropriate interventions could reduce hypoxic exposure and consequently reduce the risk of comorbidities in those with SDB, warranting early treatment interventions.

Effectiveness of Tongue-lip Adhesion for Obstructive Sleep Apnea in Infants With Robin Sequence Measured by Polysomnography

OBJECTIVE

Tongue-lip adhesion (TLA) is commonly used to relieve obstructive sleep apnea (OSA) in infants with Robin sequence (RS), but few studies have evaluated its efficacy with objective measures. The purpose of this study was to measure TLA outcomes using polysomnography. Our hypothesis was that TLA relieves OSA in most infants.

METHODS

This is a retrospective study of infants with RS who underwent TLA from 2011 to 2014 and had at least a postoperative polysomnogram. Predictor variables included demographic and birth characteristics, surgeon, syndromic diagnosis, GILLS score, preoperative OSA severity, and clinical course. A successful outcome was defined as minimal OSA (apnea-hypopnea index score < 5) on postoperative polysomnogram and no need for additional airway intervention. Descriptive, bivariate, and regression statistics were computed, and statistical significance was set at P < .05.

RESULTS

Eighteen subjects who had TLA at a mean age of 28 ± 4.7 days were included. Thirteen (72.2%) had a confirmed or suspected syndrome, and the mean GILLS score was 3 ± 0.3. All parameters trended toward improvement from the preoperative to postoperative polysomnograms, and improvement in OSA severity, oxygen saturation nadir, and arousals per hour was statistically significant (P < .02). This effect was significant across categories of surgeon, syndrome, and GILLS score. Nine subjects (50%) met the criteria for a successful outcome. Bivariate and regression analyses did not demonstrate a significant relationship between success and any predictor variable.

CONCLUSIONS

TLA improved airway obstruction in all infants with RS but resolved OSA in only nine patients, and success was unpredictable.

Submental negative pressure application decreases collapsibility of the passive pharyngeal airway in nonobese women

The pharyngeal airway is surrounded by soft tissues that are also enclosed by bony structures such as the mandible, maxilla, and cervical spine. The passive pharyngeal airway is therefore structurally analogous to a collapsible tube within a rigid box. Cross-sectional area of the tube is determined by transmural pressure, the pressure difference between intraluminal and extraluminal pressures. Due to a lack of knowledge on the influence of extraluminal soft tissue pressure on the human pharyngeal airway patency, we hypothesized that application of negative external pressure to the submental region decreases collapsibility of the passive pharynx, and that obese individuals have less response to the intervention than nonobese individuals. Static mechanical properties of the passive pharynx were compared before and during application of submental negative pressure in 10 obese and 10 nonobese adult women under general anesthesia and paralysis. Negative pressure was applied through use of a silicone collar covering the entire submental region and a vacuum pump. In nonobese subjects, application of submental negative pressure (−25 and −50 cmH2O) significantly decreased closing pressures at the retropalatal airway by 2.3 ± 3.2 cmH2O and 2.0 ± 3.0 cmH2O, respectively, and at the retroglossal airway by 2.9 ± 2.7 cmH2O and 3.7 ± 2.6 cmH2O, respectively, and the intervention stiffened the retroglossal pharyngeal airway wall. No significant mechanical changes were observed during application of submental negative pressure in obese subjects. Conclusively, application of submental negative pressure was found to decreases collapsibility of the passive pharyngeal airway in nonobese Japanese women.

[Obstructive sleep apnea syndrome in children]

Obstructive sleep apnea (OSA) is highly prevalent in school-aged children. Tonsillar and/or adenoids hypertrophy is the most common etiology of OSA in children. OSA has been associated with sleep quality disturbance (frequent arousals) and nocturnal gas-exchange abnormalities (hypoxemia and sometimes hypercapnia), complicated with a large array of negative health outcomes. The clinical symptoms are not able to distinguish primary snoring from OSA. Polysomnography remains the gold standard for the diagnosis of sleep disordered breathing, but the demand is increasing for this highly technical sleep test. So, some other simpler diagnostic methods are available, as respiratory polygraphy, but need to be validated in children. Treatment of OSA in children must be based on a mutlidisciplinary approach with pediatricians, ENT surgeons and orthodontists.

Obstructive sleep apnea in infants

Obstructive sleep apnea in infants has a distinctive pathophysiology, natural history, and treatment compared with that of older children and adults. Infants have both anatomical and physiological predispositions toward airway obstruction and gas exchange abnormalities; including a superiorly placed larynx, increased chest wall compliance, ventilation-perfusion mismatching, and ventilatory control instability. Congenital abnormalities of the airway, such as laryngomalacia, hemangiomas, pyriform aperture stenosis, choanal atresia, and laryngeal webs, may also have adverse effects on airway patency. Additional exacerbating factors predisposing infants toward airway collapse include neck flexion, airway secretions, gastroesophageal reflux, and sleep deprivation. Obstructive sleep apnea in infants has been associated with failure to thrive, behavioral deficits, and sudden infant death. The proper interpretation of infant polysomnography requires an understanding of normative data related to gestation and postconceptual age for apnea, arousal, and oxygenation. Direct visualization of the upper airway is an important diagnostic modality in infants with obstructive apnea. Treatment options for infant obstructive sleep apnea are predicated on the underlying etiology, including supraglottoplasty for severe laryngomalacia, mandibular distraction for micrognathia, tonsillectomy and/or adenoidectomy, choanal atresia repair, and/or treatment of gastroesophageal reflux.

Obstructive sleep apnea syndrome in children: Epidemiology, pathophysiology, diagnosis and sequelae

The prevalence of pediatric obstructive sleep apnea syndrome (OSAS) is approximately 3% in children. Adenotonsillar hypertrophy is the most common cause of OSAS in children, and obesity, hypotonic neuromuscular diseases, and craniofacial anomalies are other major risk factors. Snoring is the most common presenting complaint in children with OSAS, but the clinical presentation varies according to age. Agitated sleep with frequent postural changes, excessive sweating, or abnormal sleep positions such as hyperextension of neck or abnormal prone position may suggest a sleep-disordered breathing. Night terror, sleepwalking, and enuresis are frequently associated, during slow-wave sleep, with sleep-disordered breathing. Excessive daytime sleepiness becomes apparent in older children, whereas hyperactivity or inattention is usually predominant in younger children. Morning headache and poor appetite may also be present. As the cortical arousal threshold is higher in children, arousals are not easily developed and their sleep architectures are usually more conserved than those of adults. Untreated OSAS in children may result in various problems such as cognitive deficits, attention deficit/hyperactivity disorder, poor academic achievement, and emotional instability. Mild pulmonary hypertension is not uncommon. Rarely, cardiovascular complications such as cor pulmonale, heart failure, and systemic hypertension may develop in untreated cases. Failure to thrive and delayed development are serious problems in younger children with OSAS. Diagnosis of pediatric OSAS should be based on snoring, relevant history of sleep disruption, findings of any narrow or collapsible portions of upper airway, and confirmed by polysomnography. Early diagnosis of pediatric OSAS is critical to prevent complications with appropriate interventions.

Age-Specific Size of the Upper Airway Structures in Children during Development

Objectives:

The purpose of this study was to establish the largest magnetic resonance imaging study so far, by including 292 cases in a prospective fashion, to investigate the normative values of the upper airway and surrounding tissues during development.

Methods:

We enrolled in the study 448 children who underwent cranial magnetic resonance imaging. We included 292 patients who had no sleep disorders or any associated symptom that could be related to breathing disorders. Using midsagittal and axial images, we evaluated the variations in size of the upper airway tissues.

Results:

On images from the midsagittal plane, the normative values of the length and the thickness of the soft palate, the length and height of the tongue, the distance between the mental spine and the clivus, the thickness of the adenoid pad and the nasopharyngeal area, the adenoid pad oblique width, the soft palate oblique width, and the tongue oblique width were obtained for several age groups. Using images from the axial plane at the level of maximal tonsillar cross-sectional area, we measured the normative values of the mean tonsillar width and intertonsillar space.

Conclusions:

Magnetic resonance imaging is an excellent method of assessing upper airway structures. Knowledge of variations in size of the upper airway and surrounding tissues is essential in determining the significance of incidental findings in this area.

Quantitative Assessment of Tracheal Collapsibility in Infants with Tracheomalacia

Infantile tracheomalacia is a potentially life-threatening disease requiring prolonged artificial respiratory support. Diagnosis and management of this disease may be further improved by establishing a suitable objective and quantitative assessment protocol for tracheal collapsibility. It is our hypothesis that tracheal collapsibility can be represented by the relationship between intraluminal pressure and the cross-sectional area of the trachea. To test this hypothesis, static pressure/area relationships of the trachea were obtained from anesthetized and paralyzed infants, who were diagnosed as having tracheomalacia by endoscopic observation. These relationships were fitted on a linear regression model, followed by calculation of the estimated closing pressure. The tracheal closing pressure ranged from -8 to -27 cm H(2)O, suggesting easy collapsibility of the trachea during crying or coughing and noncollapsibility during the spontaneous respiratory cycle, which coincided with the infants' symptoms. It is our conclusion that tracheal collapsibility of infants with tracheomalacia can be quantitatively assessed by the static pressure/area relationship of the trachea obtained under general anesthesia and paralysis.

The pediatric airway

Good airway management technique is an essential skill for physicians in most specialties. This article begins with a review of basic airway anatomy and the physiology of the uninstrumented airway. This subject is of particular importance given the increasing use of procedural sedation and the increased recognition of sleep-disordered breathing in infants and children. A discussion of the various artificial airways and their advantages and disadvantages follows. The difficult airway is an important contributor to both patient morbidity and mortality. It is important to have a planned management approach available for the anticipated and, more importantly, the unanticipated difficult airway. The recommendations of the American Society of Anesthesiologists Taskforce on the Management of the Difficult Airway have good application for this important problem. The fetus with the prenatal diagnosis of a lesion that predicts a difficult airway presents a particular challenge. The utilization of an ex-utero intrapartum treatment method is presented as an important approach for the delivery and airway management of these infants. This section closes with a discussion of the prehospital airway management of the pediatric patient.

Influences of head positions and bite opening on collapsibility of the passive pharynx

A collapsible tube surrounded by soft material within a rigid box was proposed as a two-dimensional mechanical model for the pharyngeal airway. This model predicts that changes in the box size (pharyngeal bony enclosure size anatomically defined as cross-sectional area bounded by the inside edge of bony structures such as the mandible, maxilla, and spine, and being perpendicular to the airway) influence patency of the tube. We examined whether changes in the bony enclosure size either with head positioning or bite opening influence collapsibility of the pharyngeal airway. Static mechanical properties of the passive pharynx were evaluated in anesthetized, paralyzed patients with sleep-disordered breathing before and during neck extension with bite closure ( n = 11), neck flexion with bite closure ( n = 9), and neutral neck position with bite opening ( n = 11). Neck extension significantly increased maximum oropharyngeal airway size and decreased closing pressures of the velopharynx and oropharynx. Notably, neck extension significantly decreased compliance of the oropharyngeal airway wall. Neck flexion and bite opening decreased maximum oropharyngeal airway size and increased closing pressure of the velopharynx and oropharynx. Our results indicate the importance of neck and mandibular position for determining patency and collapsibility of the passive pharynx.

Developmental changes in upper airway dynamics

Normal children have a less collapsible upper airway in response to subatmospheric pressure administration (P(NEG)) during sleep than normal adults do, and this upper airway response appears to be modulated by the central ventilatory drive. Children have a greater ventilatory drive than adults. We, therefore, hypothesized that children have increased neuromotor activation of their pharyngeal airway during sleep compared with adults. As infants have few obstructive apneas during sleep, we hypothesized that infants would have an upper airway that was resistant to collapse. We, therefore, compared the upper airway pressure-flow (V) relationship during sleep between normal infants, prepubertal children, and adults. We evaluated the upper airway response to 1). intermittent, acute P(NEG) (infants, children, and adults), and 2). hypercapnia (children and adults). We found that adults had a more collapsible upper airway during sleep than either infants or children. The children exhibited a vigorous response to both P(NEG) and hypercapnia during sleep (P < 0.01), whereas adults had no significant change. Infants had an airway that was resistant to collapse and showed a very rapid response to P(NEG). We conclude that the upper airway is resistant to collapse during sleep in infants and children. Normal children have preservation of upper airway responses to P(NEG) and hypercapnia during sleep, whereas responses are diminished in adults. Infants appear to have a different pattern of upper airway activation than older children. We speculate that the pharyngeal airway responses present in normal children are a compensatory response for a relatively narrow upper airway.

Prone position increases collapsibility of the passive pharynx in infants and small children

On the basis of two observations that avoiding prone sleeping decreased incidence of sudden infant death syndrome and that obstructive sleep apnea is closely linked with the syndrome, we hypothesized that the prone position may increase upper airway collapsibility in infants and small children. Passive pharyngeal collapsibility of 19 infants and small children (10-101 weeks old) was examined in three postures: supine with face straight up, supine with neck rotated, and prone with neck rotated. The collapsibility was evaluated with the maximal distension of the most collapsible region, pharyngeal stiffness, and pharyngeal closing pressure, estimated from static pressure-area relationship of the passive pharynx. No significant changes in pharyngeal stiffness were detected; however, maximal distension was reduced in the prone position (mean +/- SD, 0.56 +/- 0.26 versus 0.44 +/- 0.20 cm(2); supine with face straight up versus prone position, p < 0.05). Pharyngeal closing pressure increased at neck rotation in the supine position (-4.5 +/- 2.4 versus -2.8 +/- 2.3 cm H(2)O; supine with face straight up versus supine with neck rotated, p < 0.05), and a further increase was observed in the prone position (-0.3 +/- 2.9 cm H(2)O, p < 0.05 versus supine with neck rotation). Pharyngeal closing pressure in the prone position was above atmospheric pressure in half of our subjects, whereas all subjects had negative pharyngeal pressure in the supine position. We conclude that the prone position increases upper airway collapsibility, although the mechanism is yet unclear.

Use of nasal cannula for detecting sleep apneas and hypopneas in infants and children

We evaluated tolerance of nasal cannula (NC) by 14 infants (median age, 2.6 months) and 16 children (median age, 5.5 years) with suspected obstructive sleep apnea syndrome and compared the efficacy of the NC with that of a nasobuccal thermistor in detecting obstructive apneas (OA) and obstructive hypopneas (OH) on polysomnography traces. The relationship between cannula flow and esophageal pressure was assessed in six patients. Time spent with an uninterpretable flow signal was longer when using a cannula than when using a thermistor in infants (p < 0.05) and children (p < 0.01), and it was longer in the younger patients (p < 0.05). Among the 650 OA-OH detected by either method, only 38% were detected by both, and 58% were detected by the cannula and missed by the thermistor, so that the apnea-hypopnea index was higher with cannula than with thermistor in each age group (p < 0.01). More hypopneas than apneas were detected by the cannula and missed by the thermistor (p < 0.001). Out-of-phase thoracic and abdominal motions and/or changes in the end-tidal CO(2) signal shape were associated with 86% of OH identified by cannula. In the six patients whose esophageal pressure was measured, all respiratory events identified using a cannula were associated with increased "airway resistance." Thus, the NC is more likely than the thermistor to detect OA and OH in infants and children, and this superiority is particularly marked for hypopneas.

Linear dimensions of the upper airway structure during development: assessment by magnetic resonance imaging

The upper airway undergoes progressive changes during childhood. Using magnetic resonance imaging (MRI), we studied the growth relationships of the tissues surrounding the upper airway (bone and soft tissues) in 92 normal children (47% males; range, 1 to 11 yr) who underwent brain MRI. None had symptoms of sleep-disordered breathing or conditions that impacted on their upper airway. MRI was performed under sedation. Sequential T1-weighted spin echo sagittal and axial sections were obtained and analyzed on a computer. We measured lower face skeletal growth along the midsagittal and axial oropharyngeal planes. In the midsagittal plane the mental spine-clivus distance related linearly to age (r = 0.86, p < 0.001). Along this axis, the dimensions of tongue, soft palate, nasopharyngeal airway, and adenoid increased with age and maintained constant proportion to the mental spine-clivus distance. Similarly, a linear relationship was noted for mandibular growth measured along the intermandibular line on the axial plane and age (r = 0.78, p < 0.001). In addition, the intertonsillar, tonsils, parapharyngeal fat pads, and pterygoids widths maintained constant proportion to intermandibular width with age. We conclude that the lower face skeleton grows linearly along the sagittal and axial planes from the first to the eleventh year. Our data indicate that soft tissues, including tonsils and adenoid, surrounding the upper airway grow proportionally to the skeletal structures during the same time period.