Purpose: To measure the upper airway changes associated with maxillary distraction osteogenesis in cleft lip and palate patients in the immediate post operative period and 12 months later. Materials and Methods: Seven patients with repaired cleft lip and palate (CLP) presented with severe maxillary hypoplasia. They were examined initially at T1 predistraction phase. Records taken included radiographs (orthopantograms OPG, lateral cephalometric, posteroanterior). Cephalometric analysis was done to evaluate the upper airway. Mean age is 17 years and the reverse overjet > 6 mm. They underwent maxillary Le Fort I distraction using external rigid distracters (RED). Cephalometric analysis to evaluate the upper airway was repeated at the end of the consolidation phase T2 and twelve months after distractor removal T3. Results: The range of maxillary advancement was between 8 - 15 mm (mean 9 mm). The anteroposterior distance of the superior velopharynx (PPS) and middle velopharynx (SPPS) increased at T2. A small amount of reduction in these values was recorded at T3. The inferior velopharynx (MPS) and the oropharynx (IPS, EPS) showed minimum increase in anteroposterior distance in only two patients at T2 and no change at T3. Conclusion: All seven patients showed clinical improvement in the upper airway and an increase in the upper airway values on lateral cephalometric radiographs.
Cleft lip and palate patients usually present with a challenging midface hypoplasia that creates both esthetic and functional problems in addition to a compromised upper airway. The severe scaring from previous surgeries restricts the maxillary growth and adds more insult to injury, making this condition a more complex one to manage. In the past, the standard Le Fort I advancement was the treatment of choice. However, with the emergence of Distraction Osteogenesis (DO) and its application in the orofacail region, a new diversion was created. DO has been widely used to advance the midface region in subjects with severe maxillary deficiency using the External Rigid Distractor (RED) [
The advantages of DO are numerous, including the ability of the soft tissues to gradually remodel and adapt to the underlying bony advancement. This is a great advantage in cleft lip and palate patients who present with severe palatal scaring and require large maxillary advancements. For this reason surgeons applied distraction osteogenesis methods on cleft lip and palate patients and reported the effectiveness of distraction on function and esthetics [
The aim of this retrospective study was to measure the upper airway changes that occurred with maxillary distraction osteogenesis in cleft lip and palate patients in the immediate post operative period and 12 months later.
In this study we included seven cleft lip and palate patients (CLP) with severe maxillary hypoplasia and a reverese overjet (>6 mm). They were all evaluated and treated at the oral-maxillofacial surgery clinic between 2007-2011. Four patients had bilateral CLP and three had unilateral CLP. Their ages ranged between (16 - 21) mean age 18.2 years. Clinical examination revealed severe maxillary hypoplasia with a class III dental malocclusion and reverse overjet. All patients had normal mandibular growth and development according to cepha- lometric records. They all underwent surgical repair of the cleft lip and palate during the first two years of life. This was followed by surgical repair of the alveolar cleft using iliac bone graft at variable ages ranging between 11 - 14 years.
Initial records were obtained at T1 including clinical picture and radiographs (orthopantograms OPG, lateral cephalometric, posteroanterior).
All seven patients had an occlusal discrepancy of 6mm and more due to the hypoplastic maxilla. Under general anesthesia and oral intubation. All Patients with a velopharyngeal flap were intubated successfully using fiberoptic intubation and the flap was left intact. A high Le Fort I osteotomy was performed and the maxilla was down fractured fixed to the RED (KLS Martin, Tuttlingen, Germany) using 2 mm plates and screws. After a 7- day latency period the distractor was activated at a rate of 1 mm per day in 2 rhythms. When the desired amount of maxillary advancement was achieved with an adequate occlusal overjet, the distraction was discontinued . After completing a three month consolidation period a second set of cephalometric records were obtained T2 and the distractor was removed followed by a close postoperative follow up period. During the postoperative follow up a third set of cephalometric records were obtained after a twelve month follow up period T3 (figure 1(a), figure 1(b)).
We used the most commonly used landmarks in orthodontic analysis to assess upper airway changes following the evaluation methods used by Mochida et al. [
posterior pharyngeal space (SPPS) is the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the dorsum of the soft palate on a line parallel to the FH plane that runs through the middle of the line from the PNS to the tip of the soft palate (P). The middle pharyngeal space (MPS) is the anteropos- terior depth of the pharynx measured between the posterior pharyngeal wall and the dorsum of the tongue on a line parallel to the FH plane that runs through P. The inferior pharyngeal space (IPS) is the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the surface of the tongue on a line parallel to the FH plane that runs through C2. The epiglottic pharyngeal space (EPS) is the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the surface of the tongue on a line parallel to the FH plane that runs through the tip of the epiglottis [
In Seven patients (four females and three males), three patients with unilateral CLP and four patients with bilateral CLP underwent maxillary le fort I distraction osteogenesis using RED. The age ranged between (16 - 21) mean age 18.2 years. The range of maxillary advancement was between 8 - 15 mm (mean 9 mm). All seven patients showed an improvement in esthetics and in the upper airway values on lateral cephalometric radiographs (table 1). Five patients showed resolution of the mouth breathing. In all seven patients there was a clinically evident increase in the anteroposterior distance of the superior velopharynx (PPS) mean (6 mm) and middle velopharynx (SPPS) mean (3.14 mm) at T2. A small amount of reduction in these values were recorded at T3 PPS mean reduction (1.28 mm), SPPS mean reduction (1.27 mm). The inferior velopharynx (MPS) showed minimum increase at T2 mean (2 mm) and minimum reduction at T3 mean (0.71 mm).The oropharynx (IPS,EPS) showed increase in anteroposterior distance except in two patients at T2 mean IPS 2.71 mm, EPS 2.14 mm and no change at T3.
Patient no. | sex | age | Cleft type | Amount of maxillary advancement (mm) | PPS (mm) | SPPS (mm) | MPS (mm) | IPS (mm) | EPS (mm) |
---|---|---|---|---|---|---|---|---|---|
1 | F | 18yr | Unilateral | 12 | T1 25 T2 33 T3 32 | 10 14 14 | 8 13 12 | 6 10 10 | 5 8 8 |
2 | F | 16yr | unilateral | 8 | T1 28 T2 32 T3 30 | 20 23 20 | 19 20 20 | 14 14 14 | 15 16 15 |
3 | M | 19yr | unilateral | 16 | T1 13 T2 21 T3 20 | 19 20 19 | 9 12 11 | 8 9 9 | 10 10 10 |
4 | F | 20yr | bilateral | 17 | T1 13 T2 19 T3 18 | 12 14 12 | 13 13 13 | 8 10 10 | 7 9 7 |
5 | F | 19yrs | bilateral | 12 | T1 21 T2 26 T3 25 | 18 22 21 | 24 25 24 | 22 25 27 | 11 17 15 |
6 | M | 21yr | bilateral | 10 | T1 30 T2 34 T3 33 | 11 16 15 | 11 13 12 | 8 16 17 | 9 17 15 |
7 | M | 20yr | Bilateral | 12 | T1 23 T2 30 T3 28 | 20 23 22 | 28 30 29 | 20 21 21 | 10 12 10 |
*PPS; palatal pharyngeal space, SPPS; superior posterior pharyngeal space, MPS; middle pharyngeal space, IPS; inferior pharyngeal space, EPS; epiglottic pharyngeal space.
How maxillary distraction osteogenesis alters the upper airway structure in cleft lip and palate patients is still a widely explored topic with many unanswered questions. Some reports stated that CLP patients with surgically repaired clefts had many dimensional and physiologic differences in their airway compared to non CLP patients [
Results from this study indicate that maxillary advancement using distraction osteogenesis has lead to many changes in the upper airway. It showed an increase in palatal pharyngeal space (PPS) and superior posterior pharyngeal space (SPPS) in the immediate post distraction phase with a slight decrease in PPS during the follow up phase. This decrease in the PPS was found to be related to a relapse in maxillary position due to the pulling forces exerted by the surrounding soft tissues during the follow up period. One study reported a close link between the change in PNS position and the decrease in nasal resistance. It also noted that despite a slight decrease in the PPS, the increase in the upper airway dimension and the reduction in nasal resistance was still significant one year after maxillary distraction in CLP patients [
The change in upper airway structure and function was also noted in the acute change that followed orthognathic Le Fort I advancement [
We also noted a change in the lower airway dimensions with a slight increase in the, middle pharyngeal space (MPS) and the inferior pharyngeal space (IPS). However, these changes were only evident in patients that presented initially with a steep mandibular plane angle due to a posterior vertical maxillary excess that seemed to lock the mandible in an inferior-posterior position. With the maxillary distraction, the mandible autorotated into a more anterior position leading to an increase in the lower airway dimensions. Other studies have reported some change in the lower airway after maxillary distraction, however this was not found to be significant [
One of the drawbacks of maxillary advancement in CLP patients is velopharyngeal (VPI) insufficiency especially in patients with existing VPI preoperatively. This can be explained by the increase in anterior-posterior dimensions of the nasopharynx. However, some studies suggested that the VPI will not be observed unless the maxillary advancement using conventional Le Fort I exceeds 10 mm [
Some studies have suggested that adaptive changes in the soft palate morphology occur to preserve the oropharyngeal seal after maxillary advancement [
In our study we have demonstrated the upper airway changes that occurred after maxillary DO in CLP patients. We have found a clinically evident increase in the anteroposterior distance of the superior velopharynx (PPS) and middle velopharynx (SPPS) with less increase in the inferior velopharynx (MPS) and the oropharynx (IPS, EPS). The draw backs of this study is that lateral cephalometric records were used to measure airway changes as this was a retrospective study and lateral cephelomtric radiographs do not give a three dimensional evaluation for the airway. Although all patients reported clinical improvement in breathing during sleep, future studies to evaluate upper airway changes with volumetric measures using cone beam CT would help unveil the mystery of airway changes in CLP patients after maxillary DO.
S.Abuzinada,A.Alyamani, (2016) Upper Airway Changes after Maxillary Distraction Osteogenesis in Cleft Lip and Palate Patients. Open Journal of Stomatology,06,22-27. doi: 10.4236/ojst.2016.61003