Relations Between Hyoid-Related Cephalometric Measurements and Severity of Obstructive Sleep Apnea

Predictors for cure of obstructive sleep apnea in bariatric patients

INTRODUCTION

Obstructive sleep apnea (OSA) is common among candidates for bariatric surgery and is often underdiagnosed. Given that obesity and OSA share comorbidities and mutually reinforce each other, it is important to identify factors that predict OSA resolution after bariatric surgery. However, studies on this topic are limited and offer contradictory results. The objective of the study was to identify predictors of OSA resolution one year after bariatric surgery.

METHODS

A prospective study was conducted with bariatric surgery candidates aged 18-65. Patients underwent preoperative cardiorespiratory polygraphy (PR) and an otorhinolaryngological examination. A follow-up PR was performed one year after surgery. A multivariate analysis was conducted, examining anthropometric, metabolic, and upper airway anatomical variables to determine predictors of resolution.

RESULTS

The prevalence of OSA was 75%. Predictors of resolution included preoperative body mass index (BMI), neck circumference and age. Each additional kg/m² in BMI reduced the probability of resolution by 14% (OR = 0.86; P = .037), each additional centimeter of neck circumference reduced the probability by 16% (OR = 0.84; P = .018), and each year of age reduced the probability by 11% (OR = 0.89; P = .009).

CONCLUSIONS

The prevalence of OSA in bariatric patients is high, and BMI, neck circumference, and age are predictive factors of OSA resolution after bariatric surgery.

Influence of natural hyoid bone position and surgical repositioning on upper airway patency: a computational finite element modeling study

The hyoid bone's inferior baseline position in obstructive sleep apnea (OSA) has led to surgical hyoid repositioning (SHR) treatment, yet outcomes vary widely. The influence of baseline hyoid position (BHP; phenotype) and SHR on upper airway (UA) function remains unclear. We aimed to investigate their impact on the UA using computational modeling. A validated finite element model of the rabbit UA was advanced and used to simulate changes in BHP and SHR, alone and in combination. The hyoid was displaced in cranial, caudal, anterior, anterior-cranial, and anterior-caudal directions from 1 to 4 mm. Model outcomes included UA collapsibility, measured using closing pressure (Pclose), cross-sectional area (CSA), and soft tissue mechanics (displacement, stress, and strain). Graded BHP increments increased Pclose for all directions and up to 29%-43% at 4 mm (relative to the original BHP). Anterior-based SHR decreased Pclose (approximately -115% at 4 mm) and increased ΔCSA (approximately +35% at 4 mm). Cranial SHR decreased ΔPclose (-29%), minimally affecting CSA. Caudal SHR increased ΔPclose (+27%) and decreased ΔCSA (-7%). Anterior-cranial and anterior-caudal SHR produced the highest stresses and strains. SHR effects on UA outcomes were dependent on BHP, with more caudal BHPs leading to less effective surgeries. In conclusion, BHP (phenotype) and SHR both alter UA outcomes, with effects dependent on hyoid displacement direction and magnitude. BHP influences the effectiveness of SHR in reducing UA collapsibility. These findings provide further insights into the hyoid's role in UA patency and suggest that considering the hyoid's baseline position and surgical repositioning direction/increment may help improve hyoid surgeries for OSA treatment.NEW & NOTEWORTHY Using computational modeling, this study directly shows that any shift from the healthy natural hyoid bone position increases upper airway collapsibility. Surgical hyoid repositioning alters upper airway outcomes in a direction- and magnitude-dependent manner, with its effects influenced by the natural hyoid position. Accounting for both the natural hyoid position and individually prescribed surgical repositioning may enhance upper airway stability and improve outcomes in obstructive sleep apnea (OSA) treatment.

Cephalometric Evaluation in Patients with Obstructive Sleep Apnea undergoing Lateral Pharyngoplasty

Introduction  Lateral pharyngoplasty (LP) has shown promising results. Craniofacial deformity reduces the pharyngeal space, contributing to the etiopathogenesis. The analysis of craniofacial features can be performed using cephalometry. Objective  To verify if craniofacial deformity is associated with worse polysomnographic data in patients with obstructive sleep apnea (OSA), and to verify if the preoperative cephalometric parameters can interfere with the surgical success of the LP. Methods  The study included 21 patients with OSA aged between 18 and 65 years who underwent LP in a university hospital from 2015 to 2019. Polysomnography was performed postoperatively, after a minimum period of 6 months from the surgical procedure. In addition, a cephalometric evaluation was performed to assess craniofacial deformity, and to correlate it with the polysomnographic results. Results  The mean and median of all polysomnographic respiratory parameters improved postoperatively, especially the apnea-hypopnea index (AHI), which went from 40.15 to 16.60 events per hour ( p  = 0.001). Of the 21 patients, 15 showed improvements in the AHI postoperatively. As for the cephalometric evaluations, we found that the longer the distance between the hyoid bone and the mandibular plane, the greater the patient's preoperative AHI ( p  = 0.011). When assessing whether cephalometric changes related to craniofacial deformities influence the surgical outcome of LP, no correlation was found for any cephalometric measurement. Conclusion  The longer the distance between the hyoid bone and the mandibular plane, the greater the preoperative AHI, and LP was an effective OSA treatment. Cephalometric variables are not able to modify or determine the success of LP in apneic patients in the population assessed.

The Application of Ultrasound to Quantify Hyoid Motion During Drug-Induced Sleep Endoscopy

INTRODUCTION

The significance of hyoid dynamics in OSA pathophysiology remains unclear. Drug-induced sleep endoscopy (DISE) is often used for evaluating patients intolerant to positive airway pressure (PAP) therapy. We performed DISE with concurrent hyoid-focused ultrasonography to quantify hyoid dynamics during obstructive and non-obstructive breathing.

METHODS

A cross-sectional analysis from a prospective cohort of patients undergoing DISE with PAP titration (DISE-PAP) and hyoid-focused ultrasound was conducted. Hyoid ultrasound was performed during obstructive breathing, and non-obstructive breathing after PAP administration. Motion was quantified by generating displacement curves based on echo-tracking hyoid movement. The image analysis protocol for quantifying hyoid displacement was performed independently by two researchers, and reliability of measures was assessed. Univariate and multivariate regressions were performed for various clinical data and hyoid displacement during obstructive breathing.

RESULTS

Twenty patients met inclusion criteria. On average, the cohort was male (75%), elderly (65.9 ± 10 years), overweight (29.3 ± 3.99 kg/m2 ), and with moderate-to-severe OSA (29.3 ± 12.5 events/h). Mean hyoid displacement during obstructive breathing was 5.81 mm (±3.48). In all patients, hyoid displacement decreased after PAP administration (-3.94 mm [95% CI: -5.10, -2.78]; p < 0.0001). Inter-rater reliability for measures of hyoid displacement was excellent. After multivariate regression, hyoid displacement at baseline was associated with higher AHI (β [95% CI] = 0.18 [0.03, 0.33], p = 0.020).

CONCLUSION

During DISE, hyoid displacement is greater during obstructive breathing with significant variability amongst patients. Further, these ultrasonographic measurements had excellent intra- and inter-rater reliability. Additional, larger studies are needed to understand contributors to hyoid mobility.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:3221-3227, 2023.

Craniofacial and upper airway morphological characteristics associated with the presence and severity of obstructive sleep apnea in Chinese children

Objectives

To identify craniofacial and upper airway morphological characteristics associated with the presence and severity of obstructive sleep apnea (OSA) in children.

Methods

This study consisted of 82 OSA children and 77 controls (age 5-10 years). All subjects underwent cephalograms and were divided into a 5-7 age group and an 8-10 age group. Cephalometric variables were compared between OSA children and controls, and hierarchical regression analysis was performed to examine the relationship between cephalometric variables and OSA severity [expressed by the obstructive apnea-hypopnea index (OAHI)] in different age groups.

Results

Increased A/N ratio, narrowed posterior airway space, decreased SNA and SNB angles, and shortened ramus height were observed among OSA children in different age groups. In the 5-7 age group, the A/N ratio and a lower gonial angle explained 40.0% and 14.7% of the variance in the OAHI, respectively. In the 8-10 age group, the BMI z-score and A/N ratio explained 25.2% and 6.6% of the variance in the OAHI, followed by a lower gonial angle and the hyoid-retrognathion distance (19.1% in total).

Conclusions

Adenoid hypertrophy was a major factor associated with OSA in preschool children, whereas obesity replaced adenoid hypertrophy as the main contributor to OSA in late childhood. Several craniofacial skeletal variables such as the SNB angle, ramus height, lower gonial angle, and hyoid position are also associated with the presence and/or severity of OSA, which could be used to help recognize children at a higher risk for OSA.

Position of the Hyoid Bone and Dimension of Nasopharynx and Oropharynx after Occlusal Splint Therapy and Physiotherapy in Patients Diagnosed with Temporomandibular Disorders

Background: The aim of the study was to assess the position of the hyoid bone, as well as the width of the nasopharynx and oropharynx after occlusal splint therapy combined with physiotherapy in patients diagnosed with temporomandibular disorders (TMD). Methods: This was a clinical trial study. The study group consisted of 40 patients diagnosed with TMD, who were qualified for the treatment combining physiotherapy and occlusal splint therapy. Hyoid bone position as well as the width of the nasopharynx and oropharynx were assessed in lateral cephalograms taken before and after the end of the treatment. There were 15 generally healthy participants included into the control group, who had taken lateral cephalograms twice within the period of 1 to 2 years and did not receive any occlusal treatment in the meantime. Results: The position of the hyoid bone was significantly lowered and the dimension of the lower part of the oropharynx was significantly decreased after the end of the long-term occlusal splint therapy combined with physiotherapy in patients diagnosed with TMD. Conclusions: Long-term occlusal splint therapy combined with physiotherapy affected the position of the hyoid bone and the dimension of the lower part of the oropharynx.

Association between the intensity of obstructive sleep apnea and skeletal alterations in the face and hyoid bone

Introduction

Objective

Methods

Results

Conclusion

[Ultrasound measurement of upper airway related indicators and patients with obstructive sleep apnea hypopnea correlation study of disease severity]

Objective:To compare the difference of upper airway anatomy between non-obstructive sleep apnea（OSA） patients and OSA patients, and to analyse the correlation between upper airway anatomy and the disease severity based on the upper airway ultrasound examination. Methods:Eighty-five OSA patients （OSA group） and 36 non-OSA subjects （non-OSA group） who were admitted to the Second Hosipital of Shenzhen from January 2021 to May 2021 were recruited to perform upper airway ultrasound measurement. The airway anatomical parameters were compared and analyzed by t-test. The Spearman correlation analysis was performed on the ultrasound measurement values of OSA patients with the apnea-hypopnea index （AHI） and minimum blood oxygen saturation （ LSaO2）. Results:There were statistically significant differences in BMI, the distance between the soft and hard palate junction and the hyoid bone, the angle between the hard palate and the soft palate, and the angle between the hyoid bone and the hard palate between the OSA group and the non-OSA group（P<0.001，respectively）; For 85 cases of OSA， correlation analysis between the patient's upper airway B-ultrasound measurements and AHI and LSaO2 showed that the distance from the soft and hard palate junction to the mandible, the distance from the soft and hard palate junction to the hyoid bone, the thickness of the tongue（longitudinal section）, and the thickness of the soft palate（longitudinal section）are positively correlated with AHI（r=0.3758, 0.4619, 0.3227, 0.2738, P<0.05, respectively）; the distance from the soft and hard palate to the mandible, the distance from the soft and hard palate to the hyoid bone, the width of tongue（transverse section），and the tongue thickness（longitudinal section） are negatively correlated with LSaO2（r=-0.3566, -0.5470, -0.3168, -0.3098, P<0.05, respectively）; the angle between the hard palate and the soft palate is negatively correlated with AHI（r=-0.2262, P<0.05）; the angle between the hyoid bone and the hard palate is positively correlated with AHI and negatively correlated with LSaO2（r=0.2889, -0.3351, P<0.01）. Conclusion:The upper airway related anatomical parameters based on ultrasound measurement, such as the distance from the soft and hard palate junction to the mandible, the distance from the soft and hard palate junction to the hyoid bone, the angle between the hyoid bone and the hard palate, and the angle between the hard palate and the soft palate, etc.， are associated with the disease severity in OSA patients. The correlation may be used as a potential objective indicator to evaluate the severity of patients with OSA.

Elevated Hyoid Bone Position in Response to Mandibular Advancing Appliance Predicts Effectiveness of the Appliance for Obstructive Sleep Apnea

The objective was to determine whether hyoid bone elevation induced by an anterior mandibular positioning appliance (AMP) predicts the effectiveness of the AMP in patients with obstructive sleep apnea (OSA). Fifteen patients (12 males and 3 females) underwent polysomnographic recordings and lateral cephalograms before and after AMP use of at least 6 months. Measurements of sleep variables and upper airway morphology were compared between pre-AMP and with-AMP states. The AMP appliance reduced apnea-hypopnea indices (AHI) ~53% (33.77 ± 3.29 vs. 15.85 ± 3.78, P = 0.0013). Cephalograms of the oropharyngeal airway showed that the hyoid bone moved superiorly toward the inferior mandibular border (Δ H-MP) ~5 mm (23.4 ± 1.44 vs. 18.27 ± 1.86, P = 0.0377), with the AMP inserted in the oral cavity; no airway measurement other than hyoid bone position changed. No significant correlations emerged between AHI improvement (Δ AHI) and amounts of hyoid elevation (Δ H-MP) when all patients were pooled. However, when the samples were subcategorized, the correlation coefficients increased significantly (P &lt; 0.01) in both subgroups. This outcome suggests the presence of two distinct types among the “Good-Responders” to AMP appliance use. Overall use of the AMP appliance is effective; however, the effectiveness of the appliance appears to depend on the mode of hyoid elevations, likely resulting from muscle responsiveness in patients with AMP use. The results suggest that Δ H-MP measurements may be a useful marker to segregate patients with tongue and hyoid muscles responsive to AMP from those not-so-responsive.

Relationship between cephalometric parameters and the apnoea-hypopnoea index in OSA patients: a retrospective cohort study

OBJECTIVE

The purpose of this study was to assess the relationship between cephalometric parameters and apnoea-hypopnoea index (AHI) controlling for the effect of gender, age, and body mass index (BMI) on a large sample of patients with obstructive sleep apnoea (OSA).

METHODS

This retrospective cohort study was conducted on the lateral cephalograms of 253 Caucasian adult OSA patients. Cephalometric analyses were performed using 14 parameters for skeletal and soft tissue morphology, including antero-posterior and vertical jaw relationships, hyoid bone position, soft palate length and thickness, airway space, and tongue length and height. A hierarchical regression was run to examine the amount of variability in AHI that cephalometric variables explained after controlling for patients' general characteristics (gender, age, and BMI).

RESULTS

After controlling for gender, age, and BMI, the increase in AHI variance accounted for by cephalometric parameters was equal to 0.103. Among the cephalometric variables, only MP-H and PNS-P were statistically significant (P < 0.05).

LIMITATIONS

Given the retrospective nature of the study, it is difficult to assess whether other confounding variables not considered in the present study could have influenced the relationship between cephalometric parameters and AHI.

CONCLUSIONS

This study revealed the existence of a relationship between OSA severity and some cephalometric parameters. Indeed soft palate length and vertical position of the hyoid bone were significant predictors of AHI in adult Caucasian OSA patients.

Obstructive sleep apnea in adults

INTRODUCTION

Obstructive Sleep Apnea and Hypopnea Syndrome (OSAS) is a highly prevalent disease with serious consequences for the patients' lives. The treatment of the condition is mandatory for the improvement of the quality of life, as well as the life expectancy of the affected individuals. The most frequent treatments provided by dentistry are mandibular advancement devices (MAD) and orthognathic surgery with maxillomandibular advancement (MMA). This is possibly the only treatment option which offers high probability of cure.

OBJECTIVE

The present article provides a narrative review of OSAS from the perspective of 25 years of OSAS treatment clinical experience.

CONCLUSION

MADs are a solid treatment option for primary snoring and mild or moderate OSAS. Patients with severe apnea who are non-adherent to CPAP may also be treated with MADs. Maxillomandibular advancement surgery is a safe and very effective treatment option to OSAS.