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Effects of maxillomandibular advancement on respiratory function and facial aesthetics in obstructive sleep apnoea patients with versus without maxillomandibular deficiency
Correspondence to: Department of Oral and Maxillofacial Surgery, Amsterdam UMC location University of Amsterdam, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
Department of Oral and Maxillofacial Surgery, Amsterdam UMC – location University of Amsterdam, University of Amsterdam, Amsterdam, the NetherlandsAcademic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the NetherlandsDepartment of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
Department of Oral and Maxillofacial Surgery, Amsterdam UMC – location University of Amsterdam, University of Amsterdam, Amsterdam, the NetherlandsAcademic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the NetherlandsDepartment of Oral and Maxillofacial Surgery, Northwest Clinics, Alkmaar, the Netherlands
Department of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
Department of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
Department of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the NetherlandsDepartment of Otorhinolaryngology – Head and Neck Surgery, OLVG, Amsterdam, the NetherlandsDepartment of Otorhinolaryngology – Head and Neck Surgery, Antwerp University Hospital, Antwerp, Belgium
Department of Oral and Maxillofacial Surgery, Amsterdam UMC – location University of Amsterdam, University of Amsterdam, Amsterdam, the NetherlandsAcademic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
The aim of this study was to compare the effects of maxillomandibular advancement (MMA) on respiratory function between obstructive sleep apnoea (OSA) patients with and without maxillomandibular deficiency, and to compare the changes in facial aesthetics after MMA between the two groups. MMA-treated patients who had both baseline and follow-up polysomnography (PSG) data and lateral cephalograms were enrolled in this retrospective study. In addition to PSG and cephalometric data, patient satisfaction with postoperative breathing and facial aesthetics, and overall satisfaction with the treatment were assessed. Twenty-one patients were classified as not having maxillomandibular deficiency (without-deficiency group) and 40 patients as having maxillomandibular deficiency (with-deficiency group). The improvements in respiratory parameters (e.g., apnoea–hypopnoea index) and patient satisfaction with postoperative breathing were comparable in the two groups (P = 0.094–0.713). The changes in facial profile measurements (e.g., nasal prominence, nasolabial angel, and lip positions relative to the true vertical line) and patient satisfaction with postoperative facial aesthetics were also comparable in the two groups (P = 0.148–0.983). In conclusion, no significant difference in the effects of MMA on respiratory function and facial aesthetics between OSA patients with and without maxillomandibular deficiency was observed.
Continuous positive airway pressure (CPAP) was introduced in 1981, and since that time it has become the gold standard therapy for moderate to severe OSA.
Acceptance and adherence to continuous positive airway pressure therapy in patients with obstructive sleep apnea (OSA) in a Southeast Asian privately funded healthcare system.
Riley and Powell pioneered the use of maxillomandibular advancement (MMA) for the treatment of OSA in the mid-1980 s, due to the recognition of the aetiology of OSA, which often involves concomitant maxillary and mandibular deficiencies.
MMA consists of advancement of the maxillomandibular complex by osteotomies of the maxilla and mandible, thus leading to enlargement of the pharyngeal space and reduction of pharyngeal collapsibility.
Since the advancement of both jaws is functionally and aesthetically beneficial to patients with maxillomandibular deficiency (maxillary and mandibular retrognathia), MMA has been primarily employed as the first-line treatment for OSA patients with this deficiency.
Nevertheless, MMA is also used to treat OSA patients without this deficiency but with other specific indications, for example failure or intolerance of other forms of therapy, or complete concentric collapse at the velum level as observed with drug-induced sleep endoscopy (DISE).
Three-dimensional volumetric changes in the upper airway after maxillomandibular advancement in obstructive sleep apnoea patients and the impact on quality of life.
and there is still room for improvement. Besides, due to the limited evidence on the clinical efficacy of MMA in OSA patients without maxillomandibular deficiency,
in clinical practice some sleep specialists are of the opinion that MMA should preferably be performed for OSA patients with significant mandibular deficiency. More evidence on the efficacy of MMA in OSA patients without deficiency is therefore needed.
The unacceptable alteration in facial profile following MMA is also of great concern to OSA patients, especially for those without maxillomandibular deficiency, which may dissuade OSA patients from considering MMA as a treatment option.
Therefore, the objectives of this study were (1) to compare the effects of MMA on respiratory function between OSA patients with and without maxillomandibular deficiency based on respiratory parameters measured by polysomnography (PSG) and patient satisfaction with postoperative breathing, and (2) to compare the changes in facial aesthetics after MMA between the two groups based on cephalometric measurements and patient satisfaction with postoperative facial aesthetics.
Materials and methods
This retrospective study was deemed not to be subject to the Medical Research Human Subjects Act by the Medical Ethics Committee of the Amsterdam UMC (location AMC) and a formal approval was therefore waived (Reference number W19_170#19.209).
Participants
Participants were recruited from a consecutive series of patients with OSA undergoing MMA in the Department of Oral and Maxillofacial Surgery, Amsterdam UMC (location AMC), between November 2010 and March 2020. The following inclusion criteria were applied: age ≥ 18 years; presence of OSA diagnosed by PSG preoperatively; CPAP failure or intolerance; patients with a follow-up PSG at least 3 months after MMA; and patients with a preoperative cephalogram and a follow-up cephalogram at least 6 months after MMA. The exclusion criteria were as follows: patients who declined the use of their data for research purposes; edentulous individuals; previous history of Le Fort I osteotomy and/or bilateral sagittal split osteotomy (BSSO); and syndromic patients.
All of the patients were classified into one of two groups, based on the maxillofacial skeletal criteria of the Steiner analysis
: those without maxillomandibular deficiency (without-deficiency group), i.e. patients with sella–nasion–A-point angle (SNA)> 80.5° and sella–nasion–B-point angle (SNB)> 78.5°; those with maxillomandibular deficiency (with-deficiency group), i.e. patients with SNA ≤ 80.5° and/or SNB ≤ 78.5°.
Polysomnography
All patients included in this study underwent an overnight PSG at baseline and at least 3 months after surgery (mean 5.4 ± 2.8 months). The PSG recordings were scored manually according to the American Academy of Sleep Medicine (AASM) criteria.
Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine.
The collected PSG parameters included preoperative and postoperative apnoea–hypopnoea index (AHI), oxygen desaturation index (ODI), and lowest oxygen saturation (LSAT). Based on Sher’s criteria, surgical success was defined as a postoperative AHI of less than 20 events/h and at least 50% reduction in AHI following surgery.
A standard lateral cephalogram was taken before and at least 6 months after surgery (mean 12.8 ± 7.7 months). Each radiograph was taken in centric occlusion and with the lips in relaxed position. All of the cephalograms were traced by one observer using Viewbox 4 software (dHAL Software, Kifissia, Greece). The landmarks and reference planes are shown in Fig. 1. The variables were classified into hard tissue variables, upper airway variable (Fig. 2), and soft tissue variables (Fig. 3). To assess the reliability of the cephalometric analysis, the same observer randomly selected 10 lateral cephalograms and repeated the measurements 1 month later.
Fig. 1Cephalometric landmarks and reference lines. Landmarks: S, sella; N, nasion; A, A-point; B, B-point; Go, gonion; Pog, pogonion; G′, soft tissue glabella; Pn, pronasale; Cm, columella; Sn, subnasale; UL, upper lip; LL, lower lip; Pog′, soft tissue pogonion. Reference lines: SN, a plane running through S and N; HRL, horizontal reference line, a line through S at 7° from SN; VRL, vertical reference line, a perpendicular line dropping from HRL and passing through S; TVL, true vertical line, a line perpendicular to HRL and passing through Sn; E-line, a line running through Pn and Pog′.
Fig. 2Hard tissue and upper airway cephalometric measurements. 1, S–N–A-point angle (SNA); 2, S–N–B-point angle (SNB); 3, A-point–N–B-point angle (ANB); 4, distance from A-point to VRL (A–VRL); 5, distance from B-point to VRL (B–VRL); 6, distance from Pog to VRL (Pog–VRL); 7, posterior airway space, width of the airway along Go–B-point line (PAS ).
Fig. 3Soft tissue cephalometric measurements. 1, nasal prominence, distance from Pn to a line perpendicular to HRL and passing through UL; 2, nasolabial angle, Cm–Sn–UL angle; 3, distance from UL to TVL (UL–TVL); 4, distance from LL to TVL (LL–TVL); 5, distance from Pog′ to TVL (Pog′–TVL); 6, distance from UL to E-line (UL–E-line); 7, distance from LL to E-line (LL–E-line); 8, facial convexity, G′–Sn–Pog′ angle.
All patients underwent a MMA procedure (Le Fort I osteotomy of the maxilla and BSSO of the mandible) with or without counterclockwise rotation of the maxillomandibular complex, performed by two dedicated surgeons. Rigid fixation with titanium miniplates and screws was used to stabilize the maxillary and mandibular osteotomies. Additional procedures, including genioplasty and genioglossus advancement, were performed in certain cases. The patients treated during the earlier years of the study period had a two-dimensionally planned operation, using a standard surgical protocol with the goal of 8–10 mm advancement of the maxillomandibular complex. The patients treated later during the study period had a three-dimensionally planned operation, using a personalized surgical protocol. In the personalized protocol, the final position of the bony segments was determined comprehensively by taking into account multiple patient-related factors, i.e. the severity of the OSA, skeletal pattern, dental occlusion, and facial characteristics. In addition, given that scar tissue resulting from prior upper airway surgery could restrict the MMA surgical movement, when patients had received extensive prior airway surgery, the planned degree of advancement was appropriately reduced. Upper airway collapse patterns were also taken into account when preoperative DISE was available. For example, a sufficient degree of mandibular advancement was planned when there was significant collapse of the tongue base and/or the epiglottis during DISE.
Subjective evaluation
At least 6 months after MMA, a self-assessment questionnaire was mailed to the patients to subjectively evaluate their perceptions of the MMA surgery for OSA. The patients were requested to use an 11-point VAS to separately indicate the level of satisfaction with postoperative breathing, satisfaction with postoperative facial aesthetics, and overall satisfaction with the MMA treatment, with 0 representing ‘not satisfied at all’ and 10 representing ‘completely satisfied’.
Statistical analysis
Data were analysed using IBM SPSS Statistics version 26 (IBM Corp., Armonk, NY, USA). Quantitative data were reported as the median and interquartile range (IQR). Categorical data were reported as the frequency and percentage. To determine intra-observer reliability of the cephalometric analysis, the intra-class correlation coefficient (ICC) was determined for the repeated measurements. Normality was tested using the Shapiro–Wilk test. To compare quantitative variables between the without-deficiency and with-deficiency groups, the independent-samples t-test was used when the data were normally distributed and the Mann–Whitney U-test was used when the data were not normally distributed. Differences between the two groups in categorical variables (sex and presence or absence of counterclockwise rotation, genioglossus advancement, and genioplasty) were assessed by χ2 test or Fisher’s exact test as appropriate. For the comparison of the preoperative and postoperative values, the paired-samples t-test was applied in the case of normally distributed data and the Wilcoxon signed-rank test in the case of non-normally distributed data. Spearman correlation analysis was used to assess the correlation between the reduction in AHI and facial aesthetics satisfaction score. A P-value< 0.05 was considered statistically significant.
Results
Patient characteristics
In total, 104 patients underwent MMA for OSA during the study period. Forty-three patients were excluded from the study for the following reasons: declined the use of their data for research (n = 3), edentulous individuals (n = 17), and absence of a preoperative or a follow-up cephalogram (n = 23). Therefore, 61 patients were included in this study (78.7% male, 21.3% female; median age 50.0 (IQR 44.0, 58.5) years; median body mass index (BMI) 29.0 (IQR 26.4, 31.3) kg/m2; median AHI 49.6 (IQR 35.1, 67.4) events/h).
The ICC of the cephalometric analysis ranged from 0.914 to 0.996, indicating excellent intra-observer reliability.
According to the skeletal criteria of the Steiner analysis, 21 out of the 61 patients did not have maxillomandibular deficiency preoperatively (median SNA 83.3° (IQR 81.9°, 85.4°), median SNB 79.4° (IQR 78.6°, 82.2°)). Among the 40 patients with maxillary and/or mandibular deficiency (median SNA 79.8° (IQR 76.8°, 81.3°), median SNB 73.3° (IQR 71.6°, 75.9°)), 23 (57.5%) had concomitant maxillary and mandibular deficiency, 16 (40%) had only mandibular deficiency, and one (2.5%) had only maxillary deficiency.
Baseline characteristics of the two study groups, without-deficiency versus with-deficiency
When comparing the baseline characteristics between the without-deficiency and with-deficiency groups, no significant difference was found in the baseline demographic and PSG variables. For baseline soft tissue measurements, a more protrusive position of the upper lip (UL–TVL) (P = 0.017), lower lip (LL–TVL) (P < 0.001), and soft tissue pogonion (Pog′–TVL) (P < 0.001) relative to the true vertical line (TVL) was observed in the without-deficiency group, while a significantly larger facial convexity (P = 0.011) was observed in the with-deficiency group. In contrast, the nasal prominence, nasolabial angle, position of the upper lip relative to the E-line (UL–E-line), and position of the lower lip relative to the E-line (LL–E-line) did not differ significantly between the two groups (Table 1).
Table 1Baseline characteristics of the two study groups, without and with maxillomandibular deficiency; median (IQR) values.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
Nasolabial prominence, mm
15.8 (13.3, 20.0)
18.3 (14.4, 20.7)
0.065
Nasolabial angle, degrees
119.7 (113.2, 125.2)
121.0 (113.8, 129.1)
0.347
UL–TVL, mm
1.2 (−0.6, 3.4)
− 0.1 (−2.4, 2.1)
0.017*
LL–TVL, mm
0.2 (−2.0, 1.2)
− 4.4 (−7.0, −2.6)
< 0.001*
Pog′–TVL, mm
− 5.1 (−8.0, 0.2)
− 13.5 (−18.1, −9.6)
< 0.001*
UL–E-line, mm
− 6.0 (−9.8, −3.1)
− 4.0 (−6.7, −1.4)
0.132
LL–E-line, mm
− 4.3 (−6.9, −2.7)
− 2.6 (−7.1, −0.6)
0.397
Facial convexity, degrees
7.1 (3.2, 12.3)
13.4 (5.8, 18.8)
0.011*
AHI, apnoea–hypopnoea index; BMI, body mass index; IQR, interquartile range; LL–E-line, distance from lower lip to E-line; LL–TVL, distance from lower lip to true vertical line; LSAT, lowest oxygen desaturation; ODI, oxygen desaturation index; PAS, posterior airway space; Pog′–TVL, distance from soft tissue pogonion to true vertical line; UL–E-line, distance from upper lip to E-line; UL–TVL, distance from upper lip to true vertical line.
a P-value for the comparison of the without-deficiency and with-deficiency groups; * P < 0.05 was considered statistically significant.
b For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
Clinical efficacy of maxillomandibular advancement
The surgical characteristics and airway space in the two study groups are summarized in Table 2. The degree of advancement of A-point and B-point did not differ significantly between the two groups, while the degree of advancement of pogonion (Pog) was significantly greater in the with-deficiency group (P = 0.046). The increase in posterior airway space (PAS) following MMA did not differ significantly between the two groups (P = 0.264) (Table 2).
Table 2Surgical characteristics and airway space in the two study groups, without and with maxillomandibular deficiency; median (IQR) values.
An overview of the preoperative and postoperative PSG values in the two study groups can be found in Table 3. A significant reduction in median AHI from 41.6 (IQR 32.1, 62.6) events/h to 11.1 (IQR 6.2, 27.1) events/h in the without-deficiency group (P < 0.001) and from 52.2 (IQR 35.3, 69.6) events/h to 10.3 (IQR 4.9, 21.9) events/h in the with-deficiency group (P < 0.001) was observed. There was no significant difference between the two groups in the improvements in AHI, ODI, and LSAT. Surgical success was achieved in 57.1% of the without-deficiency group compared to 67.5% of the with-deficiency group (P = 0.423), while surgical cure was achieved in 14.3% of the without-deficiency group compared to 27.5% of the with-deficiency group (P = 0.398).
Table 3Preoperative and postoperative polysomnographic values in the two study groups, without and with maxillomandibular deficiency; median (IQR) values.
P-value for the comparison of the postoperative values between the without-deficiency and with-deficiency groups. For all tests, * P < 0.05 was considered statistically significant.
a P-value for the comparison of the preoperative to postoperative change (∆) between the without-deficiency and with-deficiency groups.
b P-value for the comparison of the postoperative values between the without-deficiency and with-deficiency groups. For all tests, * P < 0.05 was considered statistically significant.
Change in facial aesthetics after maxillomandibular advancement
After MMA, significant decreases in nasal prominence and nasolabial angle, as well as significant increases in UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line were observed in both groups (P = 0.046 to P < 0.001). A significant decrease in facial convexity was found in the with-deficiency group (P < 0.001), but not in the without-deficiency group (P = 0.070).
The changes in soft tissue measurements were comparable in the two groups. Postoperatively, UL–TVL (P = 0.002), LL–TVL (P < 0.001), and Pog′–TVL (P < 0.001) were more protrusive in the without-deficiency group than in the with-deficiency group and the facial convexity was significantly lower in the without-deficiency group (P = 0.012), while the nasal prominence, nasolabial angle, UL–E-line, and LL–E-line were similar in the two groups (Table 4).
Table 4Preoperative and postoperative soft tissue measurements in the two study groups, without and with maxillomandibular deficiency; median (IQR) values.
P-value for the comparison of the postoperative values between the without-deficiency and with-deficiency groups. For all tests, *P < 0.05 was considered statistically significant.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
, mm
− 4.3 (−6.9, −2.7)
− 1.7 (−4.8, 1.2)
0.001 *
2.4 (−0.1, 4.1)
− 2.6 (−7.1, −0.6)
− 2.0 (−3.7, 1.5)
0.002 *
1.1 (−0.4, 3.2)
0.403
0.735
Facial convexity, degree
7.1 (3.2, 12.3)
4.0 (1.0, 9.7)
0.070
− 2.2 (−5.5, 2.8)
13.4 (5.8, 18.8)
11.1 (4.6, 14.3)
<0.001 *
− 2.7 (−6.8, −0.3)
0.502
0.012*
IQR, interquartile range; LL–E-line, distance from lower lip to E-line; LL–TVL, distance from lower lip to true vertical line; Pog′–TVL, distance from soft tissue pogonion to true vertical line; UL–E-line, distance from upper lip to E-line; UL–TVL, distance from upper lip to true vertical line; ∆, preoperative to postoperative change.
a P-value for the comparison of the preoperative to postoperative change (∆) between the without-deficiency and with-deficiency groups.
b P-value for the comparison of the postoperative values between the without-deficiency and with-deficiency groups. For all tests, *P < 0.05 was considered statistically significant.
c For UL–TVL, LL–TVL, Pog′–TVL, UL–E-line, and LL–E-line, a positive value is for a position in front of the TVL or E-line, and a negative value is for a posterior position.
Thirty (49.2%) questionnaires were completed and returned: 10 by patients without maxillomandibular deficiency and 20 by patients with deficiency. In the without-deficiency group, the number of patients reporting a satisfaction score ≥ 7 in terms of postoperative breathing, facial aesthetics, and overall satisfaction was six (60%), five (50%), and four (40%), respectively; in the with-deficiency group, it was 10 (50%), 13 (65%), and 11 (55%), respectively. The number of patients in the without-deficiency group reporting a satisfaction score< 3 in terms of breathing, facial aesthetics, and overall satisfaction was one (10%), two (20%), and four (40%), respectively; in the with-deficiency group, it was four (20%) for all.
The median VAS scores for satisfaction for both groups are shown in Table 5. The without-deficiency group reported the highest level of satisfaction with breathing, followed in descending order by facial aesthetics and overall satisfaction, while the with-deficiency group reported the highest level of satisfaction with facial aesthetics and overall satisfaction, followed by satisfaction with breathing. On comparison of the median VAS satisfaction scores between the two groups, the degree of satisfaction with breathing (P = 0.713), satisfaction with facial aesthetics (P = 0.983), and overall satisfaction (P = 0.681) did not differ significantly.
Table 5Patient satisfaction in the two study groups, without and with maxillomandibular deficiency; median (IQR) values.
The correlation analysis showed that for both groups, the degree of satisfaction with facial aesthetics was not related to the reduction in AHI (without-deficiency group: r = −0.006, P = 0.987; with-deficiency group: r = 0.109, P = 0.647).
Discussion
This study compared the treatment efficacy and changes in facial aesthetics after MMA between OSA patients with and without maxillomandibular deficiency. The main findings were as follows: (1) MMA surgery was equally effective in improving respiratory parameters for patients with and without such deficiency; (2) the changes in soft tissue profile measurements following MMA did not differ significantly between the two groups; and (3) the two groups had similar levels of satisfaction with postoperative breathing and facial aesthetics, and overall satisfaction with treatment.
The finding that the effect of MMA on respiratory parameters did not differ significantly between patients with and without deficiency is in line with a previous study by Ronchi et al.,
even though the two studies used different definitions of maxillomandibular deficiency. Ronchi et al. concluded that the improvements in AHI and Epworth Sleepiness Scale (ESS) after MMA were comparable in the OSA patients with and without skeletal anomalies.
The present study also found that patient perception of breathing after MMA was mainly positive and similar in both groups, which further supports MMA as an effective treatment option for patients with OSA, even in those without a skeletal deficiency. MMA surgery is generally thought to enlarge the airway space and stiffen the pharyngeal soft tissues by expanding the facial skeletal framework, thereby preventing airway collapse during sleep.
The present study found that after MMA, the increase in PAS was comparable in patients with and without deficiency, which may partially explain the equal efficacy in the two groups. Additionally, it was found that neither baseline AHI nor baseline PAS differed between patients with and without deficiency. This may support the notion that the choice of MMA as the primary treatment for OSA should depend mainly on the disease severity and restriction of PAS rather than on the dentofacial skeletal characteristics.
It is interesting to note that although a surgical success rate of 57.1% and 67.5% was observed in the without-deficiency group and with-deficiency group, respectively, the surgical cure rate was only 14.3% for the without-deficiency group and 27.5% for the with-deficiency group. This difference between the surgical success and cure rates has also been observed in other studies on MMA.
For the patients whose OSA is improved but not cured after MMA, the authors suggest a collaboration between the surgeon and a sleep specialist to find the potential causes of the residual sleep apnoea, and to evaluate the necessity for adjunctive therapy based on the severity of the residual OSA, patient symptoms, and patient preferences.
The patients treated earlier in the study period had a two-dimensionally planned operation, using a standard surgical protocol with the goal of 8–10 mm advancement; those treated later in the study period had a three-dimensionally planned operation in which the degree of advancement was personalized according to multiple patient-related factors, such as the severity of the OSA, skeletal pattern, and facial characteristics. It was anticipated that the degree of MMA advancement would be greater in patients with deficiency than in those without deficiency, however there was no significant difference between the two groups in the degree of advancement of A-point and B-point. This was because approximately 70% of the study population were treated with a standard surgical protocol. To further optimize the OSA treatment with MMA, future research should compare the surgical outcomes between the standard and personalized planned MMA.
According to the literature, the facial soft tissue should be evaluated 6 months after orthognathic surgery, in order to allow it to heal nearly completely.
In this study, the facial profile was assessed at least 6 months after surgery (mean 12.8 months); the role of residual oedema in the observed soft tissue changes is thus likely to be negligible. After MMA, the protrusion of the upper lip, lower lip, and chin relative to TVL increased significantly, accompanied by a decrease in nasal prominence, nasolabial angle, and facial convexity. These findings are consistent with those of previous studies.
the protrusion of the upper lip and lower lip increased significantly after MMA, but the increase was less than the increase relative to TVL. This is because the increased prominence of the chin can balance the lip protrusion relative to the E-line.
According to Ricketts’ analysis, the upper lip and lower lip in patients of White European descent should be estimated 4 mm and 2 mm behind the E-line respectively,
with variations among different ethnicities. For both groups, the median of the postoperative UL–E-line (without-deficiency group −3.8 mm; with-deficiency group −3.0 mm) and postoperative LL–E-line (without-deficiency group −1.7 mm; with-deficiency group −2.0 mm) were similar to the norms reported by Ricketts. However, due to the unknown ethnicities of the present study population, this conclusion should be considered with care. Taken together, the findings suggest that although MMA can significantly alter the soft tissue facial profile, the balance between the nose, lips, and chin is acceptable for patients with and without deficiency.
Another point to be noted is that no significant difference was found between patients with and without deficiency with regard to the changes in facial profile measurements. Conley and Boyd
evaluated the facial soft tissue changes following MMA for the treatment of OSA, and concluded that the changes in soft tissue corresponded to nearly 90% of the underlying skeletal movements for most anatomical sites of the upper lip, lower lip, and chin. In the present study, the magnitude of the skeletal advancement did not differ significantly between the two groups. It is therefore not surprising that the corresponding changes in facial profile were comparable in the two groups.
Interestingly, despite the significant differences observed between the two groups in postoperative facial profile measurements, there was no significant difference between the two groups in perception of facial aesthetics. This suggests that these objective soft tissue measurements may not play an important role in patient satisfaction with facial aesthetics. This is further supported by the results of the post-hoc Spearman correlation analysis on the correlation between the facial aesthetics satisfaction score on the one hand and soft tissue changes and post-surgical soft tissue variables on the other hand, in which only the change in LL–E-line was negatively associated with the degree of satisfaction with facial aesthetics (r = −0.542, P = 0.002). Thus, it can be advocated that the position of the lower lip in relation to the E-line should be integrated into the MMA surgery plan for OSA treatment. It is important to note that most people do not look at themselves in profile but rather look straight in a mirror, and while there are some soft tissue changes that can be observed by a discerning eye from frontal view, they are far less obvious than profile changes. Another point to be noted is that the patients might have imposed their own cultural bias during the subjective evaluation.
Additionally, it is likely that OSA patients, especially those without a baseline maxillomandibular deficiency, accept their alteration in facial aesthetics due to the improvement in OSA, as the main motivation for MMA in these patients is treatment of the OSA. Nevertheless, no significant correlation was found between the facial aesthetics satisfaction score and the improvement in AHI in this study population.
The study results should be interpreted with caution due to certain limitations. Firstly, as with any retrospective analysis, a weakness of the study was the inability to control the data. There is also a potential concern for selection bias, as only 60% of the total MMA cohort were enrolled in this study. However, no significant differences in baseline characteristics (age, sex distribution, BMI, neck circumference, and baseline AHI) were observed between the patients who were included in the study and those who were not. Furthermore, half of the study population did not respond to the questionnaire, which might have caused a non-response bias.
In addition, the incorporation of genioplasty or genioglossus advancement as an additional procedure in MMA should be considered as a confounding factor. Nevertheless, given that the additional procedure was only performed in six patients, it might not have played a leading role in the results observed. Counterclockwise rotation involved in MMA may also have an impact on respiratory function and facial aesthetics. However, since counterclockwise rotation was not a main focus of interest in this study and was performed equally in both groups (47.6% vs 52.5%, P = 0.717), it was decided not to take it into consideration in the analyses. Lastly, the study cohort comprised predominantly middle-aged and elderly male patients with a relatively high BMI (overweight) and of unknown ethnicity. This limits the generalizability of the findings. Larger, prospective multicentre studies are needed to further confirm the current findings. Additionally, a validated questionnaire would be preferable for the subjective assessments in future research.
Within the limitations of this study, it is concluded that there is no significant difference in the effects of MMA on respiratory function and facial aesthetics between OSA patients with and without maxillomandibular deficiency. This supports the view that MMA can also be considered as an appropriate treatment for OSA patients without maxillomandibular deficiency.
Funding
None.
Competing interests
GA has received research grants from Sunstar Suisse SA and Vivisol-ResMed and is an unpaid member of the academic advisory board for Oral Function (Sunstar Suisse SA). NvD is a member of the Medical Advisory Board of NightBalance and consultant to Philips Healthcare, Inspire, and Nyxoah. The other authors have no conflicts of interest.
Ethical approval
This retrospective study was approved by the Medical Ethics Committee of the Amsterdam UMC (location AMC) (Reference number W19_170#19.209).
Patient consent
Patient consent was not required.
References
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Three-dimensional volumetric changes in the upper airway after maxillomandibular advancement in obstructive sleep apnoea patients and the impact on quality of life.
Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. Deliberations of the Sleep Apnea Definitions Task Force of the American Academy of Sleep Medicine.
☆The preliminary findings of this study were presented as an Abstract at the American Academy of Dental Sleep Medicine 30th Anniversary Meeting in Dallas, Texas, May 13–15, 2022.
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