Abstract
This study evaluates the outcome and change in facial appearance after maxillomandibular advancement (MMA) in Chinese adults with severe obstructive sleep apnoea hypopnoea syndrome (OSAHS). Twelve patients underwent MMA with adjunctive procedures for severe OSAHS. All underwent physical examination, Epworth Sleepiness Scale evaluation, cephalometry, polysomnography, and facial photographic assessment before and 6 months after MMA. The aesthetic plane (relationship of nose, lips, and chin) was used to judge soft tissue facial profile change after MMA. Postoperative cephalometric data were compared with normal occlusive standards and aesthetic norms. Pre- and postoperative aesthetic appearance was evaluated by 100 lay people using a 10-point visual analogue scale. The maxillomandibular complex (MMC) was advanced 5–10 mm (mean 7.4 mm). The success rate was 83%. All patients were satisfied with the functional and aesthetic results. Postoperative SNA, SNB, and posterior airway space increased and mandibular plane-to-hyoid distance decreased significantly in all patients. The lower lip was closer to EP than the preoperative and normal occlusive standard. In 11 of 12 patients, the lay aesthetic scores were significantly higher postoperatively. MMA is effective for Chinese adults with severe OSAHS. In most patients, facial appearance was more attractive after MMC advancement of 5–10 mm.
Obstructive sleep apnoea hypopnoea syndrome (OSAHS) is a common disorder characterized by repetitive episodes of upper airway collapse with increased airflow resistance during sleep. A community based study of sleep-disordered breathing among middle-aged men in Hong Kong demonstrated an OSAHS estimated prevalence of 4.1%. The prevalence of OSAHS in Chinese adults in Shanghai has been estimated to be 3.62%. Major risk factors include obesity, male gender, advancing age, and an anatomically small upper-airway (i.e. maxillary or mandibular insufficiency). Compared to Caucasians, Asian patients are less obese and have more protrusive skeletal abnormalities for a given degree of OSAHS severity.
Recently, OSAHS has been treated conservatively, most commonly using nasal continuous positive airway pressure (nCPAP) and oral appliances (OAs). These methods provide only symptomatic relief, and CPAP compliance is poor with more than 50% of patients unable to tolerate it. Soft-tissue surgical procedures are now available to increase the posterior airspace and treat OSAHS in patients intolerant to CPAP. The reported surgical success rate for these procedures is approximately 40–60%.
Maxillomandibular advancement (MMA) enlarges the pharyngeal space by expanding the skeletal framework of the soft-tissue pharyngeal structures and tongue resulting in a reduction in pharyngeal collapsibility during negative-pressure inspiration. MMA is currently the most effective craniofacial surgical technique for the treatment of OSAHS in adult patients with severe OSAHS and craniofacial anomalies. Based on cephalometric analysis and predication measurements, MMA was performed in patients with malocclusion and craniofacial anomalies to normalize the occlusion and to improve facial aesthetics. The purpose of MMA treatment for OSAHS is to maximize the displacement of the maxillomandibular complex (MMC), thus increasing the upper airway space. The mean 9.5 mm displacement in MMA is significantly greater than that generally undertaken for dentofacial deformity. Thus, MMA for OSAHS often causes extreme maxillomandibular protrusion and occasionally has unfavourable aesthetic results.
Chinese people have more protrusive upper and lower lips compared to Caucasians and their facial profile is more convex. Thus, displacement of the MMC induced by MMA is likely to cause unacceptable aesthetic alterations in Chinese patients. The authors think that this is one of the greatest obstacles to the widespread use of this effective method in Chinese people affected by OSAHS. Although several studies of facial changes associated with MMA have reported favourable aesthetic results from the patients’ perspective, most were performed in ethnically Caucasian cohorts. To the authors’ knowledge, no study has examined the aesthetic outcome of MMA treatment for OSAHS in Chinese patients. The conventional assessment of postoperative facial appearance after MMA has been based on the patient’s perspective using patient-administered questionnaires. A complete assessment of postoperative changes in facial appearance should include both subjective and objective data.
This study aims to assess the benefits of MMA, and evaluate whether the changes are aesthetically acceptable by polysomnography, cephalometry and facial photographic assessment.
Materials and methods
Between January 2005 and May 2010, 12 consecutive patients underwent MMA to treat severe OSAHS. In these 11 men and 1 woman, the mean age was 39.8 ± 2.4 years and the mean body mass index (BMI) 27.4 ± 2.1 kg/m 2 . Case selection norms included: failed or refused nCPAP; the obstruction of palatopharynx and hypopharynx with or without deficiency of the mandible; apnoea–hypopnoea index (AHI) > 30/h demonstrated by polysomnography (PSG); excessive daytime sleepiness (ESS > 10) and other symptoms.
All patients underwent preoperative and postoperative facial photographic assessment, Epworth Sleepiness Scale (ESS) evaluation, physical examination, cephalometry, and nocturnal PSG before and 6 months after MMA. Variables recorded included age, gender, BMI, AHI, lowest oxygen saturation (LSAT), and cephalometric data. The patient’s subjective perception of his/her facial appearance was evaluated using a standardized questionnaire. Pre- and postoperative standardized photographs of each patient were displayed randomly to a panel of 100 lay people who were asked to score the aesthetic appearance of each photograph using a 10-point visual analogue scale (VAS) at the same visit 6 months after surgery. The results were analysed 6 months postoperatively. The procedure was considered successful if the postoperative PSG showed an AHI < 20 and a decrease of more than 50%, and the patient reported significant clinical improvement. Informed written consent was obtained from all participants, and the study protocol was approved by the hospital institutional review board.
Surgical programme
MMA consisted of a Le Fort I osteotomy (LF), and bilateral sagittal split ramus osteotomies (BSSRO). The distance of the advancement depended on the initial craniofacial characteristics and the condition of computer simulation surgery. Some patients underwent concomitant adjunctive procedures. Of these, 10 patients underwent genioplasty for mandibular dysplasia diagnosed by mandibular protrusion angle (SNB < 75°). Uvulopalatopharyngoplasty had previously been carried out in three patients, simultaneously with MMA in seven patients with tonsil hypertrophy. A summary of the surgical programme for each patient is given in Table 1 . The orthodontic treatment was not performed in all patients. Since the maxilla and mandible were advanced by the same amount, the occlusal relationship remained unaltered after surgery.
| Patient no. | Sex | Age (year) | Pre AHI | Pre SNA | Pre SNB | Pre. PAS | Pre tonsil hypertrophy | Previous surgery | Surgical procedures | Distance of MMA (mm) |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | M | 34 | 51.2 | 77.3 | 70.1 | 5.5 | No | UPPP | MMA + GA | 7 |
| 2 | M | 42 | 70.1 | 78.8 | 71.7 | 7.4 | No | UPPP | MMA + GA | 5 |
| 3 | F | 43 | 49.9 | 80.0 | 67.5 | 6.5 | No | UPPP | MMA + GA | 7 |
| 4 | M | 59 | 83.3 | 80.4 | 72.0 | 6.9 | Yes | No | MMA + GA + UPPP | 8 |
| 5 | M | 44 | 49.9 | 80.3 | 70.9 | 2.0 | No | No | MMA + GA | 7 |
| 6 | M | 33 | 63 | 83.0 | 73.8 | 8.5 | Yes | No | MMA + GA + UPPP | 7 |
| 7 | M | 34 | 48.5 | 73.4 | 64.4 | 9.6 | No | No | MMA + GA | 8 |
| 8 | M | 31 | 64.3 | 79.4 | 72.0 | 5.9 | Yes | No | MMA + GA + UPPP | 7 |
| 9 | M | 35 | 71.9 | 81.9 | 73.3 | 5.9 | Yes | No | MMA + GA + UPPP | 8 |
| 10 | M | 46 | 72.9 | 85.5 | 79.0 | 11.1 | Yes | No | MMA + UPPP | 7 |
| 11 | M | 31 | 60.6 | 76.7 | 73.1 | 4.9 | Yes | No | MMA + GA + UPPP | 10 |
| 12 | M | 46 | 40.7 | 85.6 | 80.1 | 9.0 | Yes | No | MMA + UPPP | 7 |
Cephalometric imaging and analysis
Cephalometric radiographs were obtained for 12 patients by a senior examiner using a standardized technique. The patients were in the sitting natural head position at the end-expiration phase and were not swallowing. The landmarks and reference lines for conventional cephalometric analysis have been defined previously. The preoperative and postoperative cephalograms were digitized by a single investigator using the Nemoceph NX 2006 software (Nemotec SL, Madrid, Spain). The Frankfort horizontal plane was used during the measurements.
Variables analysed included: the angle from sella to nasion to subspinale (SNA); the angle from sella to nasion to supramentale (SNB); the angle between the maxilla and mandible (ANB); the distance between the base of the tongue and the posterior pharyngeal wall (PAS); the distance from the mandibular plane to hyoid bone (MP-H); nasolabial angle, the angle formed by the columella-subnasale-labrale superius (Cm-Sn-Ls); soft-tissue facial angle (FH-N′-Pg′), the angle formed from the Frankfort horizontal plane and a line dropped from the nasion to the soft-tissue pogonion; facial convexity angle (G-Sn-Pg′), the complementary angle of the angle formed by glabella, subnasale, and soft-tissue pogonion; aesthetic plane (EP) drawn between pronasale and soft-tissue pogonion (Pn-Pg′); subnasale to EP (Sn-EP); labrale superius to EP (Ls-EP); labrale inferius to EP (Li-EP); and mentolabial sulcus to EP (Si-EP). When the lips were posterior to the EP, the distances were expressed using a negative sign and when the lips were anterior to the EP, the distances were expressed using a positive sign ( Fig. 1 ). The cephalometric findings, excluding those of the one female patient, were compared with the male normal occlusive standards for typical Chinese adults described by Gu et al., and with male aesthetic norms for typical Chinese adults described by Wang et al. The cephalometric data from the female patient were excluded because the female cephalometric normal standard is different from that of the male.
Measurement error
Six randomly chosen lateral cephalograms were digitized and measured twice by the same investigator to ensure no intra-examiner error had occurred in landmark selection, tracing, or measurement error. No significant errors were found in the evaluation of the repeat measures using paired t tests.
Subjective evaluation
Patients were assessed using a comprehensive clinical history that included sleeping habits and the occurrence of sleep disturbances. Excessive daytime sleepiness or hypersomnia was determined using the ESS. A score > 10 was considered symptomatic of hypersomnia. The patient’s perception of his/her facial appearance was evaluated using a standardized questionnaire. The patients were asked to evaluate the change in the aesthetic appearance of their facial profile before and after MMA as (1) unchanged, (2) improved, or (3) worse. The patients were requested to judge their overall satisfaction with the treatment and whether they would recommend the same treatment to other patients.
Standardized photographs of facial profiles were taken using a digital camera with the patient in the natural head position and with relaxed lip posture. The subjects were positioned standing 1.7 m from the camera. Every patient’s preoperative and postoperative standardized photographs were shown randomly to a panel which scored the aesthetics of each profile using a 10-point VAS, with 1 representing the least attractive and 10 representing the most attractive. The panel participants were unaware of which photographs were pre- and postoperative. The panel consisted of 54 men (mean age 28.4 ± 4.1 years) and 46 women (mean age 26.7 ± 4.5 years). The participants were instructed to evaluate the standardized facial profile photographs objectively ignoring factors such as makeup, hairstyle, hair colour, and complexion.
Polysomnography recordings
Polysomnographic recordings were made and scored using the Alice 4 system (Philips Respironics, Murrysville, PA, USA) according to the criteria of Rechtschaffen and Kales. Obstructive apnoea was defined as the absence of airflow with respiratory effort for at least 10 s. Hypopnoea was defined as a >50% reduction in airflow accompanied by oxygen desaturation of more than 4% or arousal from sleep. AHI was defined as the number of apnoeas and hypopnoeas per hour.
Statistical analysis
All statistical analyses were performed using SPSS, version 13 (SPSS Inc., Chicago, IL, USA). Continuous data are expressed as the mean ± SD, and a P -value < 0.05 was deemed to be statistically significant. The aesthetic score for the preoperative and postoperative facial profile photographs is the mean of the profile assessment score given by the lay people for each photograph. Paired t tests were used to compare preoperative and postoperative mean values. A one-tailed t test was used to examine significant differences between the postoperative mean cephalometric values and the normal male occlusive standards, and the male aesthetic norms.
Results
Effect of MMA on OSAHS
A significant decrease in BMI was observed after surgery (preoperative BMI 27.4 ± 2.1 kg/m 2 versus postoperative BMI 26.3 ± 2.0 kg/m 2 ; P < 0.01). The AHI decreased from 60.5 ± 12.7 events per hour preoperatively to 15.3 ± 11.5 postoperatively ( P < 0.001) and the LSAT increased from 68.3 ± 12.6% preoperatively to 85.8 ± 5.9% postoperatively ( P < 0.001). The surgery was considered successful in 10 patients and two patients with AHI > 20 were defined as partial responders; thus the success rate was 83%. The ESS score decreased from 20.9 ± 3.3 preoperatively to 2.0 ± 2.7 postoperatively ( P < 0.001; Table 2 ).
| Preoperative | Postoperative | T test | P -value | |
|---|---|---|---|---|
| BMI (kg/m 2 ) | 27.45 ± 2.14 | 26.26 ± 2.01 | 3.58 | 0.004 |
| AHI (#/h) | 60.53 ± 12.66 | 15.33 ± 11.48 | 8.39 | 0.00 |
| LSAT (%) | 68.33 ± 12.62 | 85.83 ± 5.91 | −4.56 | 0.001 |
| ESS | 20.92 ± 3.34 | 2.00 ± 2.73 | 13.94 | 0.00 |
Subjective assessment
Eleven (92%) questionnaires were completed and returned by 10 men and 1 woman. Nine patients (82%) felt that changes occurred in their facial appearance, and of those, eight (72%) rated the changes as favourable (they felt they appeared more attractive). One patient (9%) responded unfavourably (the facial changes made him less attractive); this patient had normal cephalometric, occlusal characteristics prior to surgery. Two patients (18%) felt neutral regarding their facial aesthetic result.
No temporomandibular joint disorders were reported. Six patients had paraesthesia of the lower lip, which persisted almost 6 months after MMA, but was fairly well tolerated by these patients. All patients were satisfied with the functional results and said they would recommend the same treatment to other patients.
One patient (8%) did not return the questionnaire. His BMI decreased from 26.8 kg/m 2 preoperatively to 25.7 postoperatively, and his AHI decreased from 83.3 events per hour preoperatively to 13.4 postoperatively. His LSAT improved from 64% to 78%.
The lay people’s postoperative aesthetic scores were significantly higher than the preoperative scores for 11 patients ( P < 0.001), and the pre- and postoperative aesthetic score was not significantly different in one patient ( P > 0.05; Table 3 ).
| Patient number | Preoperative | Postoperative | T test | P -value |
|---|---|---|---|---|
| 1 | 3.91 ± 1.22 | 5.43 ± 1.41 | −13.87 | 0.00 |
| 2 | 5.30 ± 1.07 | 6.31 ± 1.20 | −10.65 | 0.00 |
| 3 | 4.30 ± 1.24 | 5.33 ± 1.42 | −8.18 | 0.00 |
| 4 | 4.57 ± 1.14 | 4.84 ± 1.24 | −2.40 | 0.02 |
| 5 | 5.26 ± 1.17 | 5.86 ± 1.28 | −5.97 | 0.00 |
| 6 | 4.86 ± 1.21 | 5.86 ± 1.21 | −8.35 | 0.00 |
| 7 | 3.71 ± 1.19 | 4.36 ± 1.59 | −5.49 | 0.00 |
| 8 | 4.53 ± 1.21 | 6.08 ± 1.29 | −11.41 | 0.00 |
| 9 | 4.89 ± 1.25 | 5.70 ± 1.26 | −6.38 | 0.00 |
| 10 | 4.71 ± 1.23 | 4.78 ± 1.27 | −0.53 | 0.60 |
| 11 | 5.45 ± 1.27 | 6.28 ± 1.20 | −6.61 | 0.00 |
| 12 | 5.26 ± 1.26 | 5.71 ± 1.09 | −4.81 | 0.00 |
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