Abstract
This retrospective study evaluated the effect of bimaxillary advancement surgery on pre- and postoperative 2D cephalometric soft- and hard tissue measurements, polysomnography (PSG) and patient-reported snoring scores including Epworth sleepiness scale (ESS) after multidisciplinary treatment planning in 32 patients with obstructive sleep apnea or sleep disordered breathing (OSAS/SDB). Apnea-hypopnea index significantly improved with a mean difference of 18.32 ± 13.97 ( P = 0.004). ESS, snoring intensity and snoring severity scores all significantly improved after surgery. The preoperative surgical planning was achieved based on 2D pre- and postoperative cephalometric comparison. Most 2D cephalometric measurements did not correlate with postoperative PSG findings. Amount of maxillary and mandibular advancement measured on 2D cephalograms did correlate with postoperative time below 88% oxygen saturation on PSG. In conclusion: bimaxillary advancement surgery has clinically significant favourable results in patients with OSAS/SDB both measured by PSG and with patient-reported outcomes after careful multidisciplinary treatment planning. Current 2D cephalometric airway analysis insufficiently predicted the effect of maxillomandibular advancement surgery in patients with OSAS/SDB.
Highlights
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Apnea-hypopnea index significantly improved after bimaxillary advancement surgery in OSAS/SDB patients.
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Epworth sleepiness scale, snoring intensity and snoring severity scores all significantly improved after surgery.
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Most 2D cephalometric measurements did not correlate with postoperative polysomnographic findings.
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Amount of advancement correlates with postoperative time below 88% oxygen saturation.
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The preoperative surgical planning was achieved based on 2D pre- and postoperative cephalometric comparison.
1
Introduction
Obstructive sleep apnea syndrome (OSAS) and sleep-disordered breathing (SDB) are an increasingly recognized entity with significant morbidity and considerable societal costs. Careful evaluation based on physical examination, polysomnography (PSG) and drug-induced sleep endoscopy (DISE) with Esmarch manoeuvre including multidisciplinary discussion allow for a personalized treatment planning [ ]. Patients with a retrognathic profile (skeletal class 2) and a positive effect of the Esmarch manoeuvre during DISE are good candidates for orthognathic surgery. Currently, maxillofacial treatment planning is increasingly based on two and three-dimensional imaging. It is unknown if cephalometric measurements pre- and postoperatively in patients undergoing maxillomandibular advancement (MMA) add useful information to predict the outcome in patients with SDB and OSAS. Hence, we hypothesize that changes on cephalometry correlate with positive improvement on postoperative polysomnography. Moreover, we aim to assess the effect of MMA on 2D airway measurements and if the planned surgical advancement is actually achieved. Preoperative snoring severity, intensity, snoring score and Epworth sleepiness scale score (ESS) are compared with postoperative results.
2
Materials & methods
This study has been conducted in accordance with the declaration of Helsinki and Good Clinical Practice. Informed consents were waived due to the retrospective nature of the study. We conducted a retrospective analysis of all patients diagnosed with OSAS or SDB who underwent orthognathic maxillomandibular advancement surgery between 2010 and 2017. All patients were treated by the same maxillofacial surgeon (PV). Patients were assessed pre-operatively during a multidisciplinary meeting with ENT specialists, maxillofacial surgeons, orthodontists and pneumologists. During this meeting, a specific care pathway is followed ( Fig. 1 ). All patients underwent a complete work-up prior to the multidisciplinary meeting including a thorough history and dedicated clinical examination by an ENT specialist, polysomnography interpreted by a pneumologist and drug-induced sleep endoscopy (DISE) with Esmarch manoeuvre performed by an ENT specialist. Based on this initial evaluation, a treatment plan is proposed.
Demographic data were collected as well as data from pre- and postoperative polysomnography (PSG) and 2D cephalometric analysis. Two-dimensional cephalograms were traced determining skeletal and soft tissue landmarks ( Fig. 2 , Table 1 ). Specific airway landmarks were measured according to literature and compared pre- and postoperatively. Maxillomandibular advancement was measured by the difference between points AXA, AXB, AXPg ( Fig. 2 ). Data from preoperative surgical planning was collected. Specifically the planned movements, to allow comparison with final achieved advancement measurements. Data from a snoring questionnaire was collected pre- and postoperatively in dutch ( Appendix 1 ). This questionnaire included snoring intensity, snoring severity and a snoring score. Patients were asked to complete the questionnaire together with their bed partner. Additionally the Epworth sleepiness scale was registered.
| Landmark | Description |
|---|---|
| SNA (°) | Angle formed between the plane constructed from Nasion (N) to Sella (S) and point A |
| SNB (°) | Angle formed between the plane constructed from Nasion (N) to Sella (S) and point B |
| ANB (°) | Difference between SNA and SNB angles |
| AXA (mm) | Distance perpendicular from Ax to point A |
| AXB (mm) | Distance perpendicular from Ax to point B |
| AXPg (mm) | Distance perpendicular from Ax to Pogonion (Pg) |
| SN | Line connecting Sella (S) and Nasion (N) |
| Horizontal | Constructed by drawing a line 7° clockwise from SN with center in S |
| Ax | True vertical Perpendicular to Horizontal |
| PNS-P (mm) | Soft palate length Linear distance between posterior nasal spine (PNS) and P |
| B-Gn | Mandibular plane Line connecting Point B with Gonion (Gn) |
| S-Gn | Line connecting Sella (S) and Gonion (Gn) |
| MP-H (mm) | Line perpendicular to Mandibular plane and most anterior superior point of the hyoid bone |
| UPW (mm) | Upper pharyngeal wall Point of intersection of the line perpendicular to the posterior pharyngeal wall from posterior nasal spine |
| PAS (mm) | Posterior airway space Distance on the mandibular plane from anterior to posterior pharyngeal wall |
| MPW (mm) | Middle pharyngeal wall Intersection of the perpendicular line from the uvula to the posterior pharyngeal wall |
| LPW (mm) | Lower pharyngeal wall Intersection of the perpendicular line from vallecula to the posterior pharyngeal wall |
Statistical analysis was performed using IBM SPSS version 25.0. Patient demographic data were calculated by number of observations, mean, median, standard deviation and range. Categorical variables are described using absolute counts and percentages. A paired Wilcoxon signed rank test was applied to detect differences between sleep tests before and after surgery. For AHI and time saturation under 88%, a one-sided test was performed. Spearman rank correlations and their P -value were calculated to model the relation between landmark changes and sleep test parameters. Linear regression was calculated between planned and achieved advancement. The regression coefficients and their variance-covariance matrix were used to test the hypothesis that variables and slope were equal to (0,1) by means of a Mahalanobis test. A paired samples T-test was used to compare the results from the snoring questionnaire pre- and postoperatively. Data are mean ± standard deviation unless otherwise stated. P- values lower than 0.05 were considered significant.
3
Results
In total, 32 (26 males, 81%) patients were included with a mean age of 48 years (22–64). Baseline characteristics are summarized in Table 2 . The mean snoring time was 83.2 ± 76.1 min. Mean body mass index (BMI) measured 25.8 ± 3.5 preoperatively and 25.2 ± 2.8 postoperatively. Mean preoperative apnea-hypopnea index (AHI) was 17.7 ± 13.3 and arousal index 26.6 ± 19.7. PSG analysis comparing pre (87 ± 41) and postoperative results (121 ± 43) showed a significant increase in the number of sleep stage changes ( P = 0.0497). Arousal index was significantly lower postoperatively (19.54 ± 3.12, P = 0.0195). AHI index significantly improved postoperatively with a mean difference of 18.32 ± 13.97 ( P = 0.004). No significant differences were found on following measures: total snoring time (prone/side position), time of oxygen saturation below 88%, mean heart rate during sleep, the total duration of sleep, duration of REM sleep, the total number of arousals.
| (N = 32) | Minimum | Maximum | Mean | Std. Deviation |
|---|---|---|---|---|
| Age | 22 | 64 | 47,59 | 8,66 |
| BMI | 18,0 | 33,20 | 25,84 | 3,49 |
| Apnea-Hypopnea Index | 1,40 | 52,60 | 17,65 | 13,32 |
| Arousal Index | 0,00 | 77,10 | 26,62 | 19,77 |
| Planned Maxillary Advancement | 3,00 | 10,00 | 5,04 | 1,37 |
| Planned Mandibular Advancement | 7,00 | 13,00 | 9,21 | 1,37 |
| Planned Chin Advancement | 5,00 | 8,00 | 6,00 | 1,06 |
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