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. 2026 Mar 30;26:809. doi: 10.1186/s12903-026-08171-3

Advancement genioplasty as a compensatory measure for mandibular setback-induced airway volume reduction in skeletal class III deformities: a 3D analysis of long-term outcomes

Jia Kang 1, Yao Yang 1, Ning Zhang 1, Ren Zhang 2, Siyuan Guo 1, Xiaoyu Lin 1, Xuejiu Wang 1,✉
PMCID: PMC13154449  PMID: 41913158

Abstract

Background

Airway volume changes induced by orthognathic surgery might impair patients’ sleep quality. Yet, the long-term impact of bimaxillary surgery with advancement genioplasty on airway volume of patients with skeletal class III deformities and its association with snoring remains elucidated. The study aimed to analyze changes in upper airway volume and other airway parameters after bimaxillary surgery, with or without advancement genioplasty, and to explore the association between these surgical procedures and postoperative changes in snoring.

Methods

A total of 31 patients were enrolled and divided into two groups: Group 1 (Le fort I osteotomy and mandibular setback), Group 2 (Le fort I osteotomy, mandibular setback, and advancement genioplasty). Airway parameters were calculated at three time points using three-dimensional airway reconstruction based on CT. Snoring was assessed using the Chinese version of Snore Outcomes Survey (C-SOS).

Results

No significant differences in Body mass index (BMI) and amount of bimaxillary movement were observed between two groups. The total pharyngeal airway volume (TPV) in Group 2 showed a change of -2741.50 ± 5883.63 mm3 from pre-operation to one year after surgery, while that of Group 1 was − 4344.65 ± 7542.94 mm3 (P = 0.005). Particularly, the hypopharyngeal volume (HPV) reduced even more in Group1 than in Group 2 (P < 0.001). Correspondingly, the C-SOS score of Group 2 was 62.22 ± 3.80, better than Group 1 (60.5 ± 4.82) at the one-year postoperative follow-up.

Conclusion

Advancement genioplasty effectively compensates for mandibular setback-induced airway volume reduction which supports its inclusion in surgical planning to improve postsurgical respiratory outcomes.

Keywords: Airway, Snore, Genioplasty, Mandibular setback

Background

Skeletal class III dentofacial deformity, characterized by mandibular prognathism, often accompanied by maxillary retrusion, is one of the most prevalent conditions addressed in orthognathic surgery [1]. The prevalence of skeletal class III deformities in Asian populations ranges from 12.58% to 26.67% [2]. This condition has a multifactorial etiology, involving a complex interplay of genetic factors, diseases, and other congenital or acquired conditions that lead to the disharmonious development of the jaw [3]. Orthognathic surgery, which involves repositioning the maxilla and mandible, combined with orthodontic treatment, has become increasingly common in the correction of skeletal class III deformities worldwide [4].

The realignment of the jaws significantly affects the pharyngeal area, impacting its skeletal, muscular, and soft tissue structures, including the pharyngeal muscles, soft palate, hyoid-associated muscles, and tongue base [5]. Several studies have found that a significant mandibular setback may adversely affect airway volume [6, 7]. In cases of bimaxillary orthognathic surgery, while maxillary advancement can lead to an increase in upper airway volume (UAV), the total upper airway volume still decreases because of the mandibular setback, which narrows the UAV [2, 8, 9].

Obstructive sleep apnea syndrome (OSAS) has an incidence rate of 5% to 25% in adults, with a higher prevalence in men (2–4%) than in women (1–2%) [10]. This is primarily attributed to a reduction in UAV [11]. Thus, bimaxillary surgery for skeletal class III deformities may impair UAV, potentially leading to snoring or even OSAS [12]. Upper airway stenosis is a significant concern during both surgical planning and post-operative care.

Genioplasty is an adjunctive procedure in orthognathic surgery typically used to reshape the mandible and improve facial appearance [13]. During the procedure, the chin is moved forward, and the attached muscles, such as the genioglossus and geniohyoid, are repositioned, leading to changes in the morphology of the tongue and the position of the hyoid bone [14]. The hyoid bone, a mobile structure anchored to the pharyngeal wall and mandible, functions as a pulley between these structures. This mechanism plays a critical role in expanding the UAV when the hyoid-mandibular muscles are straightened [15]. Recent studies have reported that genioplasty effectively increases pharyngeal airway volume [16]. Furthermore, the advancement and counterclockwise rotation of the maxillomandibular complex, when combined with genioplasty, significantly increase the UAV [16]. However, previous studies have only analyzed airway changes using two-dimensional imaging, which is insufficient in representing the entire UAV. The impact of bimaxillary surgery, with or without genioplasty, on the UAV remains unclear [17, 18].

This study aimed to analyze UAV changes after bimaxillary surgery with or without advancement genioplasty in patients with skeletal class III deformities using three-dimensional (3D) airway reconstruction based on CT, and to explore their effect on upper pharyngeal airway sleep disorders (UASD).

Materials and methods

Patients

A total of 31 patients with class III dentofacial deformity who underwent bimaxillary orthognathic surgery at Beijing Stomatological Hospital, Capital Medical University between January 2022 and August 2024 were included in this study. The surgical plan involved maxillary advancement and mandibular setback, with or without chin advancement. Complete preoperative and postoperative imaging data and follow-up records were available. All patients were divided into two groups based on the surgical protocol: Group 1 underwent Lefort I osteotomy and BSSRO, while Group 2 underwent Lefort I osteotomy, BSSRO, and advancement genioplasty. This study was approved by the Human Research Ethics Committee of Beijing Stomatological Hospital, Capital Medical University (CMUSH-IRB-KJ-PJ-2023-39).

CT scans and airway measurement

The demographic data included age, sex, height, weight, amount of bimaxillary and the chin movement were collected via the electronic medical record. CT scans were obtained at three time points: one month preoperatively (T0), one month postoperatively (T1), and one year postoperatively (T2). Scans were performed using a GE BrightSpeed Series 16-slice spiral CT system (BrightSpeed, GE Medical Systems, Waukesha, WI, USA). The scanning protocol was configured with the following parameters: collimation width of 1.25 mm, slice spacing of 1.25 mm, tube voltage ranging from 120 to 140 kV, tube current exceeding 200 mA, and a pitch ratio of 1.625:1. During the CT examination, patients were positioned supine without head support and instructed to maintain maximum dental intercuspation while breathing gently, avoiding swallowing or tongue movements throughout the procedure. All patients underwent CT scanning in accordance with this protocol. All CT datasets were archived in DICOM format and processed using Mimics 16.0 (Materialise, Belgium) for subsequent evaluation. Through bone tissue segmentation procedures, a comprehensive three-dimensional skull model was reconstructed and exported in STL format.

Airway measurement

Through 3D airway reconstruction using Mimics software, the following parameters were measured: upper airway volume, nasopharyngeal volume, oropharyngeal volume, hypopharyngeal volume, the minimum cross-sectional area of the pharyngeal airway, along with its corresponding anterior-posterior diameter and transverse diameter. As described in our previous study, the region from the posterior nasal spine to the fourth cervical vertebra was defined as the total pharyngeal airway volume (TPV) (Fig. 1A) [18]. The area between the posterior nasal spine and the tip of the uvula was defined as the nasopharyngeal volume (NPV), the region between the tip of the uvula and epiglottis was defined as the oropharyngeal volume (OPV), and the section from the epiglottis to the most superior point of the fourth cervical vertebra was defined as the hypopharyngeal volume (HPV) (Fig. 1B, C). The narrowest segment of the pharyngeal airway was identified as the minimum cross-sectional area (min-CSA), the anterior-posterior length (APL) and lateral transverse width (LTW) were measured on the axial slice at the level of min-CSA (Fig. 2A-C).

Fig. 1.

Fig. 1

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Measurement of airway volume. A Reconstruction of the total pharyngeal airway volume (TPV) model. B Division of nasopharyngeal volume (NPV), oropharyngeal volume (OPV), and hypopharyngeal volume (HPV) on the patient’s CT. C Reconstruction of the NPV, OPV, and HPV models

Fig. 2.

Fig. 2

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Measurement of the minimum cross-sectional area (min-CSA) related parameters. A Location of the min-CSA in the airway. B Division of anterior-posterior length (APL) and lateral transverse width (LTW) on the patient’s CT. C Reconstruction of the min-CSA models

Snore Outcomes Survey (SOS)

The Chinese version of Snore Outcomes Survey (C-SOS) was used to evaluate the duration, severity, frequency, and consequences of issues related to Sleep-Disordered Breathing (SDB), with each item containing 5 to 6 response options [19]. The C-SOS was standardized on a scale from 0 (worst) to 100 (best), with individual total scores calculated to assess snoring severity. It effectively indicated whether a patient’s snoring condition had improved, deteriorated, or remained stable compared to the preoperative state. To analyze the impact of different surgical procedures on their snoring condition, the C-SOS scores were obtained from patients at T2 (one year postoperatively) when they were re-examined.

Body Mass Index (BMI)

The BMI for each patient involved in this study was derived from objectively measured height and weight. It was determined using the standard formula: weight in kilograms divided by the square of height in meters. The height and weight data from patients at T0 and T2 for BMI calculation were calculated to rule out BMI-related changes in pharyngeal airway.

Statistical analysis

All of the statistical analyses were performed using Statistical Package for Social Sciences (SPSS, version 21.0, Chicago, IL, USA). Descriptive statistics were expressed as the mean ± standard deviation for continuous variables. The Fisher’s Exact Test was used for the analysis of categorical variables. Normality of variables was assessed using the Shapiro-Wilk test. Based on this assessment, for normally distributed data, the paired t-test was used for within-group comparisons, while the independent t-test was applied for between-group comparisons. For data that did not follow a normal distribution, within-group comparisons were conducted using the Wilcoxon signed-rank test, and between-group comparisons were performed using the Mann-Whitney U test. P-value less than 0.05 was considered statistically significant.

Results

Patients baseline data

The demographic characteristics of all patients were shown in Table 1. This study included 31 patients with a mean age of 26.10 (± 5.47) years, consisting of 10 males and 21 females. 13 patients were assigned in Group 1 and 18 patients in Group 2. The average age of Group 1 was 24.38 ± 4.79, and that of Group 2 was 27.33 ± 5.73 (P = 0.142). The average BMI of Group 1 in T0 was 22.09 ± 3.65, of Group 2 was 21.48 ± 2.48 (P = 0.582). The average amount of maxillary movement in Group 1 and Group 2 was 2.41 ± 2.51 mm and 2.08 ± 1.59 mm, respectively (P = 0.663). The average amount of mandible movement in Group 1 and Group 2 was − 6.23 ± 2.28 mm and − 5.28 ± 2.65 mm, respectively (P = 0.305). The results showed that there was no significant difference observed in two groups regarding the bimaxillary movement and BMI. The amount of chin advancement in Group 2 was 4.31 ± 2.43 mm.

Table 1.

Baseline information of patients

Variables Group 1 (n = 13) (Mean ± SD) Group2 (n = 18) (Mean ± SD) P-value
Age 24.38 ± 4.79 27.33 ± 5.73 0.142
Sex 7 (male) 3 (male) 0.052
6 (female) 15 (female)
Height (m) 1.72 ± 0.08 1.66 ± 0.07 0.053
Weight T0 (kg) 65.45 ± 13.71 59.80 ± 10.35 0.198
Weight T2 (kg) 65.71 ± 14.04 60.09 ± 10.05 0.201
BMI T0 22.09 ± 3.65 21.48 ± 2.48 0.582
BMI T2 22.18 ± 3.74 21.61 ± 2.60 0.625
Amount of maxillary movement (cm) 2.41 ± 2.51 2.08 ± 1.59 0.663
Amount of mandibule movement (cm) -6.23 ± 2.28 -5.28 ± 2.65 0.305
Amount of chin (cm) 0 4.31 ± 2.43 < 0.001
C-SOS 60.5 ± 4.82 62.22 ± 3.80 0.286
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Abbreviation: SD Standard deviation, BMI Body mass index, C-SOS The Chinese version of Snore Outcomes Survey

Airway volume assessment

The results of TPV, NPV, OPV, HPV, min-CSA, APL and LTW at T0, T1, and T2 in two groups were presented in Table 2. The results showed that Group 1 exhibited a continuous decline in postoperative airway volume compared to the preoperative baseline, whereas Group 2 demonstrated a more modest reduction. For example, the TPV of Group 1 was 25660.42 ± 9648.49 mm3 at T0, but decreased to 21315.78 ± 5257.99 mm3 at T2 (P = 0.005). However, the TPV of Group 2 was 22954.66 ± 7403.06 mm3 at T0, and decreased to 20213.16 ± 6607.44 mm3 at T2 (P = 0.555). This indicated that mandibular setback resulted in a reduction in UAV even when accompanied by maxilla advancement.

Table 2.

Airway parameters of the pharyngeal airway in preoperative and postoperative surgery

Airway parameters Group 1 (n = 13) (Mean ± SD) Group2 (n = 18) (Mean ± SD)
T0 T1 T2 T1-T0P T2-T1P T2-T0P T0 T1 T2 T1-T0P T2-T1P T2-T0P
NPV (mm3) 11920.64 ± 5148.96 10024.88 ± 3163.95 10210.36 ± 3455.83 0.046 0.707 0.019 10180.30 ± 4081.69 9727.36 ± 4177.30 9532.80 ± 3909.26 0.832 0.569 0.882
OPV (mm3) 9329.39 ± 4318.24 8101.27 ± 3570.81 7839.18 ± 3334.73 0.173 0.606 0.027 8701.03 ± 3173.72 8582.85 ± 3978.73 7468.65 ± 3093.78 0.990 0.245 0.175
HPV (mm3) 4410.4 ± 1603.66 4087.54 ± 2280.39 3266.24 ± 1062.39 0.292 0.130 0.001 4073.33 ± 1703.32 3800.72 ± 1747.14 3211.71 ± 1097.83 0.750 0.602 0.805
TPV (mm3) 25660.42 ± 9648.49 22213.7 ± 7479.66 21315.78 ± 5257.99 0.064 0.375 0.005 22954.66 ± 7403.06 22110.93 ± 8327.57 20213.16 ± 6607.44 0.867 0.674 0.555
APL (mm) 10.22 ± 3.98 9.2 ± 3.24 10.08 ± 1.94 0.342 0.102 0.896 11.56 ± 4.64 10.31 ± 3.05 9.94 ± 2.70 0.252 0.905 0.264
LTW (mm) 32.70 ± 4.87 31.94 ± 5.28 31.29 ± 3.48 0.526 0.403 0.188 30.23 ± 4.08 30.00 ± 4.07 29.95 ± 3.54 0.675 0.938 0.737
Min-CSA (mm2) 154.34 ± 55.81 149.11 ± 63.76 136.88 ± 25.35 0.742 0.398 0.249 164.44 ± 57.44 163.06 ± 56.56 149.61 ± 53.86 0.911 0.337 0.485
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Abbreviation: SD Standard deviation, NPV Nasopharyngeal volume, OPV Oropharyngeal volume, HPV Hypopharyngeal volume, TPV Total pharyngeal airway volume, APL Anterior-posterior length, LTW Lateral transverse width, Min-CSA Minimum cross-sectional area

Additionally, to analyze the impact of advancement genioplasty for skeletal class III deformities patients on the upper airway volume, we calculated the airway parameters changes of two groups in T0, T1 and T2 (Table 3). There was no significant difference in the OPV, APL, LTW and min-CSA of two groups (P > 0.05). However, for Group 1, the average airway parameters change in NPV, HPV and TPV between T0 and T2 were − 1710.28 ± 5287.57 mm3, -1144.16 ± 1088.79 mm3 and − 4344.65 ± 7542.94 mm3, respectively. And the average airway parameters changes of Group 2 in NPV, HPV and TPV between T0 and T1 were − 647.50 ± 3160.81 mm3, -861.62 ± 1600.90 mm3, -2741.50 ± 5883.63 mm3, respectively. Group 2 exhibited a significantly milder reduction in NPV (P = 0.014), HPV (P < 0.001) and TPV (P = 0.005) compared to Group 1.

Table 3.

Comparison of airway parameters changes in two groups

Airway parameters Group 1 (n = 13) (Mean ± SD) Group2 (n = 18) (Mean ± SD) P-value
∆T1-T0 ∆T2-T1 ∆T2-T0 ∆T1-T0 ∆T2-T1 ∆T2-T0 ∆T1-T0P ∆T2-T1P ∆T2-T0P
NPV (mm3) -1895.76 ± 4435.66 185.48 ± 2993.42 -1710.28 ± 5287.57 -452.94 ± 2759.55 -194.56 ± 1971.85 -647.50 ± 3160.81 0.053 0.516 0.014
OPV (mm3) -1228.12 ± 4163.13 -262.09 ± 3476 -1490.21 ± 3707.03 -118.18 ± 2528.55 -1114.2 ± 2604.97 -1232.38 ± 2688.53 0.172 0.917 0.108
HPV (mm3) -322.85 ± 1700.13 -322.85 ± 1700.13 -1144.16 ± 1088.79 -272.61 ± 1380.29 -272.61 ± 1380.29 -861.62 ± 1600.90 0.306 0.113 < 0.001
TPV (mm3) -3446.73 ± 8171.91 -897.92 ± 5669.36 -4344.65 ± 7542.94 -843.72 ± 5584.40 -1897.77 ± 5070.18 -2741.50 ± 5883.63 0.065 0.484 0.005
APL (mm) -1.01 ± 3.68 0.87 ± 1.78 -0.14 ± 3.75 -1.25 ± 4.47 -0.36 ± 3.05 -1.61 ± 5.42 0.876 0.303 0.467
LTW (mm) -0.76 ± 4.21 -0.65 ± 2.69 -1.41 ± 3.64 -0.23 ± 2.26 -0.05 ± 2.69 -0.28 ± 3.45 0.652 0.548 0.386
Min-CSA (mm2) -5.23 ± 55.96 -12.24 ± 50.28 -17.46 ± 52.02 -1.38 ± 51.59 -13.46 ± 40.29 -14.84 ± 66.16 0.845 0.776 0.680
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Abbreviation: SD Standard deviation, NPV Nasopharyngeal volume, OPV Oropharyngeal volume, HPV Hypopharyngeal volume, TPV Total pharyngeal airway volume, APL Anterior-posterior length, LTW Lateral transverse width, Min-CSA Minimum cross-sectional area

Although other airway parameters showed no significant difference in two groups, when it comes to TPV and HPV, we believed that advancement genioplasty contributed to an increase in HPV, thereby attenuating the reduction in TPV. These results indicated that genioplasty provided a compensatory effect for the airway volume decrease induced by mandibular setback.

BMI changes

To ensure that the observed postoperative airway changes in both groups were not attributable to variations in weight, we collected anthropometric data (height and weight) and calculated the BMI for each patient at T0 and T2 (Table 4). There was no significant difference in BMI changes in two groups (P > 0.05). This demonstrated that the difference in airway volume between these two groups was not attributable to weight.

Table 4.

Comparison of BMI changes in two groups

Parameters Group 1 (n = 13) (Mean ± SD) Group2 (n = 18) (Mean ± SD)
T0 T2 P-value T0 T2 P-value
BMI 22.09 ± 3.65 22.18 ± 3.74 0.789 21.48 ± 2.48 21.61 ± 2.60 0.715
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Abbreviation: SD Standard deviation, BMI Body mass index

Snoring outcomes in two groups

Since airway narrowing is intricately linked to snoring, we investigated postoperative snoring outcomes in both groups to clarify the impact of airway changes on this symptom. The snoring outcomes of these patients were assessed using C-SOS at T2. The total C-SOS score of all patients was 61.52 ± 3.80, with Group 1 scoring 60.5 ± 4.82 and Group 2 scoring 62.22 ± 3.80 (P = 0.286) (Table 1). Although the difference did not reach statistical significance, the higher C-SOS scores in Group 2 suggested that chin advancement may contribute to improved snoring symptoms.

Discussion

Anatomically, the mandible serves as a crucial attachment point for the tongue and pharyngeal musculature. Surgical setback of the mandible, such as BSSRO, results in a posterior displacement of these soft tissues [20, 21]. This repositioning narrows the anteroposterior diameter at the oropharyngeal and hypopharyngeal levels, consequently reducing pharyngeal airway volume [20]. The impact of mandibular setback on airway volume is well-documented. For instance, Jeon JY reported an immediate reduction in postoperative airway volume after single mandible setback surgery. Despite partial recovery within one-month, complete recovery was not achieved, even at 12 months postoperatively [22]. Furthermore, Kang NE et al. found that patients who underwent mandibular setback surgery experienced a significantly greater reduction in pharyngeal airway volume, even after one year, irrespective of whether maxillary surgery was performed [23]. Another study with a longer follow-up time (up to 2 years) also revealed that the airway volume in both the oropharyngeal and hypopharyngeal regions remained significantly decreased after single mandible setback surgery [24].

The exact effect of bimaxillary surgery, which involves maxillary advancement combined with mandibular setback, on the airway remains controversial. Some studies have shown that skeletal class III patients undergoing bimaxillary surgery exhibit significant reductions in UAV, sagittal area, min-CAS, and oral cavity volume [2, 25]. Although maxillary advancement increases airway volume, the combined effect of maxillary advancement and mandibular setback still results in an overall reduction in UAV [24]. However, Gokce SM et al. reported that bimaxillary surgery mitigates airway narrowing primarily through maxillary advancement, which significantly enlarges the nasopharyngeal and oropharyngeal dimensions, thereby increasing the total airway volume [26]. These conflicting findings highlight the ongoing divergence in understanding the impact of bimaxillary surgery on airway volume in patients with skeletal class III deformities. In this study, we observed that patients with skeletal class III deformity who underwent maxillary advancement and mandibular setback surgery exhibited decreased airway volumes both shortly after surgery and at long-term follow-up which is in line with reports from previous studies [27, 28].

Genioplasty, as an adjunctive procedure, is often performed during bimaxillary surgery to improve the facial profile and appearance. Currently, an increasing number of patients in China undergo genioplasty solely to enhance their facial appearance. Specifically, chin advancement has been shown to enlarge the UAV to some extent. However, the combined effects of bimaxillary surgery and genioplasty (chin advancement) on UAV remain underexplored.

Chin advancement genioplasty primarily involves upward and forward movements, which are believed to enlarge the hypopharyngeal volume [17]. For adults with high BMI, simultaneous mandibular setback and advancement genioplasty may help mitigate the negative impact of pharyngeal airway space reduction [29]. Bimaxillary surgery in class III patients primarily affects the nasopharyngeal and oropharyngeal volumes [15]. It has been reported that the combined approach of bimaxillary surgery with genioplasty in patients with skeletal class III results in substantial hypopharyngeal volume augmentation, but does not alter the overall airway volume [30]. Besides, the extent of bimaxillary movement should be considered as an important factor when assessing its effect on airway volume [31]. Weight gain has also been significantly associated with increases in tongue fat and decreases in pterygoid and total lateral wall volumes, potentially affecting the upper airway [32]. In this study, changes in the UAV following bimaxillary surgery in class III patients, with or without advancement genioplasty, were compared. The amount of bimaxillary movement and BMI were controlled. Between T0 and T2, the average reductions in HPV and TPV were greater in patients who underwent bimaxillary surgery without genioplasty (-1144.16 ± 1088.79 mm³ and − 4344.65 ± 7542.94 mm³, respectively) compared to those with genioplasty (-861.62 ± 1600.90 mm³ and − 2741.50 ± 5883.63 mm³, respectively) (P < 0.05). We proposed that chin advancement induced an anterior repositioning of the attached genioglossus and geniohyoid muscles. This muscular displacement directly pulled the hyoid bone forward and upward. The anterior movement of the hyoid bone enlarged the retrohyoid space in the lower pharynx. Therefore, compared to patients who only underwent bimaxillary surgery, those who had concomitant chin advancement genioplasty preserved more TPV and HPV.

Patients with reduced UAV may be predisposed to snoring or sleep-disordered breathing, including OSAS [33, 34]. Anterior displacement of the genioglossus muscle, along with superior repositioning of the hyoid bone, has been suggested as a viable therapeutic option for snoring and sleep-disordered breathing [35, 36]. Given the established correlation between airway narrowing and snoring, we compared the postoperative snoring outcomes between the two patient groups and observed partial improvement in snoring symptoms among skeletal class III patients who underwent the combined procedure with advancement genioplasty. We thought that the forward advancement of the chin pulled the tongue base forward via hyoid bone displacement, which helped counteract gravity-induced tongue-base collapse in the supine position or during sleep and thus potentially contributed to the alleviation of respiratory symptoms. Therefore, when planning a mandibular setback for class III patients, the potential adverse impact on airway volume should be proactively incorporated into the surgical design. The combination of bimaxillary surgery and anterior genioplasty demonstrated significant clinical relevance for UAV preservation.

This study has some limitations. First, the sample size was relatively small, and future studies with a larger cohort of patients may further validate our results. Second, although we investigated postoperative snoring outcomes, collecting additional parameters, such as those obtained through sleep monitoring, would provide a more comprehensive assessment of the effect of bimaxillary surgery-induced UAV changes on sleep breathing. Third, these parameters such as maxillary impaction, rotation, and mandibular rotation were not quantified, and thus their independent effects on airway volume changes might be ignored. Future studies with detailed 3D analysis are needed to clarify these relationships. Finally, whether the degree of advancement genioplasty leads to differential improvements in airway volume requires further investigation.

Conclusions

In conclusion, our study proposed that advancement genioplasty effectively increased the HPV, thereby improving the TPV reduction and showing a trend toward improvement in snoring outcomes caused by mandibular setback surgery, independently of weight changes and bimaxillary movements. This supported the inclusion of genioplasty as a valuable adjunctive procedure in surgical planning to mitigate adverse effects on the airway and potentially improved respiratory outcomes.

Acknowledgements

This research was supported by Beijing Stomatological Hospital, Capital Medical University Young Scientist Program (YSP202503).

Abbreviations

SOS

Snore Outcomes Survey

C-SOS

Chinese version of Snore Outcomes Survey

BMI

Body mass index

TPV

Total pharyngeal airway volume

NPV

Nasopharyngeal volume

OPV

Oropharyngeal volume

HPV

Hypopharyngeal volume

min-CSA

Minimum cross-sectional area

APL

Anterior-posterior length

LTW

Lateral transverse width

UAV

Upper airway volume

OSAS

Obstructive sleep apnea syndrome

UASD

Upper pharyngeal airway sleep disorders

T0

One month preoperatively

T1

One month postoperatively

T2

One year postoperatively

SDB

Sleep-Disordered Breathing

Authors’ contributions

Jia Kang: Conceptualization; Data Curation; Investigation; Methodology; Validation; Visualization; Writing–Review & Editing; Writing–Original Draft Preparation. Yao Yang: Investigation; Methodology; Project Administration. Ning Zhang: Software; Validation. Ren Zhang: Data Curation; Formal Analysis. Siyuan Guo: Data Curation; Formal Analysis. Xiaoyu Lin: Data Curation. Xuejiu Wang: Conceptualization; Funding Acquisition; Project Administration; Supervision; Validation; Visualization; Writing–Review & Editing.

Funding

This research was supported by Young Scientist Program of Beijing Stomatological Hospital, Capital Medical University (YSP202503).

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

All patients in this study have signed written informed consent and this retrospective research was approved by the Human Research Ethics Committee of Beijing Stomatological Hospital, Capital Medical University (CMUSH-IRB-KJ-PJ-2023-39) in accordance with the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

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