J Oral Maxillofac Surg70:e133-e140, 2012

Pharyngeal Airway Changes AssociatedWith Maxillary Distraction Osteogenesis

in Adult Cleft Lip and Palate PatientsMuge Aksu, DDS, PhD,* Tülin Taner, DDS, PhD,†

Pınar Sahin-Veske, DDS, PhD,‡ Ilken Kocadereli, DDS, PhD,§Ersoy Konas, MD,! and Mehmet Emin Mavili, MD¶

Purpose: To investigate 1) the changes in pharyngeal airway sizes associated with maxillary distractionosteogenesis and 2) the correlations between maxillary skeletal variables and the pharyngeal airway inadult patients with cleft lip and palate.

Patients and Methods: The study was carried out in 14 adult subjects with cleft lip and palate.Predistraction records were taken at a mean age of 22.7 ! 4.6 years. All patients had placement of a rigidexternal distraction device (RED I; KLS Martin, Tuttlingen, Germany) after Le Fort I osteotomy. Lateralcephalograms were assessed before surgery and at short-term follow-up (8.0 ! 6.4 months). Thecephalometric skeletal and pharyngeal airway variables were statistically evaluated by use of theWilcoxon signed-rank test. Spearman ! correlation was performed to check the correlations betweenmaxillary skeletal and pharyngeal variables.

Results: The maxillary movement was 8.7 mm (P " .01). The maxillary depth angle (#7.9°) andeffective maxillary length (9.4 mm) increased significantly (P " .01) after distraction, whereas the palatalplane angle remained unchanged. Anterior nasal spine (8.2 mm) and Posterior nasal spine (6.9 mm)moved anteriorly. The overjet increased (9.5 mm) significantly (P " .01). Posterior, superoposterior, andmiddle airway spaces increased significantly, with mean differences of 7.5 mm, 5.1 mm, and 3.3 mm,respectively. The soft palate moved anteriorly, with the greatest movement at its superior point.Significant positive correlations were observed for the posterior and superoposterior airway spaces andmaxillary movement. PNS changes showed the highest correlation with posterior airway changes.

Conclusions: The significant anterior movement of the maxilla resulted in significant increases inposterior, superoposterior, and middle airway spaces. The posterior airway space showed the highestsignificant positive correlation with the movement of PNS. The posterior and superoposterior airwayspaces also showed significant positive correlations with the maxillary skeletal variables.© 2012 American Association of Oral and Maxillofacial SurgeonsJ Oral Maxillofac Surg 70:e133-e140, 2012

Treatment of severe maxillary hypoplasia, especiallyin cleft patients, has been unstable in both horizontaland vertical dimensions when treated by conven-tional Le Fort I maxillary advancement.1-5 With ad-vances in knowledge and techniques, corrective surgeryprogressed mainly by use of distraction procedures, par-

ticularly for the patients with cleft lip and palate (CLP).Rigid external distraction can improve occlusion, masti-catory function, and esthetics by changing the positionof the maxilla dramatically.6 The gradual anterior move-ment of the maxilla also allows the soft tissue to remodelin harmony with the hard tissue, providing effective

*Associate Professor, Department of Orthodontics, Faculty of

Dentistry, Hacettepe University, Ankara, Turkey.

†Professor, Department of Orthodontics, Faculty of Dentistry,

Hacettepe University, Ankara, Turkey.

‡Private Practice, Manavgat, Antalya, Turkey.

§Professor and Head, Department of Orthodontics, Faculty of

Dentistry, Hacettepe University, Ankara, Turkey.

!Instructor, Department of Plastic, Reconstructive and Aes-

thetic Surgery, Faculty of Medicine, Hacettepe University, An-

kara, Turkey.

¶Professor and Head, Department of Plastic, Reconstructive and

Aesthetic Surgery, Faculty of Medicine, Hacettepe University, An-

kara, Turkey.

Address correspondence and reprint requests to Dr Aksu: Depart-

ment of Orthodontics, Faculty of Dentistry, Hacettepe University,

Sihhiye, 06100, Ankara, Turkey; e-mail: muge.aksu@hacettepe.edu.tr

© 2012 American Association of Oral and Maxillofacial Surgeons

0278-2391/12/7002-0$36.00/0

doi:10.1016/j.joms.2011.10.009

e133

stability of the maxillary bone. Therefore, because theamount of maxillary anterior shift is large, the maxil-lary position, the skeletal pattern, the soft palate po-sition, and the pharyngeal airway size are thought toshow more change and better stability than withconventional surgical interventions.7

In CLP patients Class III malocclusion with severemaxillary retrusion may lead to a constriction of theupper airway. Many studies have attempted to investi-gate the effect of surgical treatment techniques such asLe Fort I osteotomy, sagittal split ramus osteotomy, orcombined bimaxillary surgery on the airway in Class IIImalocclusion.8-13 Harada et al14 examined the preoper-ative and postoperative changes of velopharyngeal (VP)functions after maxillary distraction and found increasesin both nasopharyngeal depth and velar length. In 2004Mochida et al7 reported the effects of maxillary distrac-tion on the upper airway size. They showed that themaxillary distraction led to an increase in the upperairway size and a decrease in the nasal resistance, whichremained stable even after 1 year.

Although the maxillary distraction technique hasbeen widely used in the midface region for the treat-ment of CLP, few studies have been reported on howmaxillary distraction osteogenesis alters the upper air-way structure. The previously mentioned studies com-prised both adult and children with a wide age range.7,14

However, children’s upper airways have specific ana-tomic characteristics that differ from those of adults.Children have a relatively large tongue, a high larynx, arelatively large epiglottis, bulging arytenoid cartilage,and a soft trachea, all factors explaining why minorchanges in the airway dimensions yield respiratory con-sequences. Another challenge in evaluating the changesof pharyngeal structures in children is to balance con-cerns related to continuing growth. Jeans et al15 re-ported that the pharyngeal structures continue to growrapidly until 13 years of age.

The data that have been presented so far have notdistinguished the changes in airway size in childrenand those in adult patients with CLP. Therefore moredetailed information about the changes in pharyngealairway size after maxillary distraction is needed.

The aim of this study was to investigate 1) thechanges in pharyngeal airway sizes associated withmaxillary distraction osteogenesis; and 2) the corre-lations between maxillary skeletal variables and thepharyngeal airway in adult patients with CLP.

Patients and MethodsThe study was carried out in 14 adult subjects (6

men and 8 women), consisting of 7 with unilateralCLP and 7 with bilateral CLP. Because the study wasretrospective, it was exempt from our institutionalreview board approval. Predistraction records were

taken at a mean age of 22.7 ! 4.6 years. Subjectsexamined in this study are presented in Table 1.Medical history showed that all patients had beenoperated on for the primary closure of the defects ofthe lip and the hard and soft palate during the firstyear of life. None of the patients had secondary alve-olar bone grafting previously. The expansion of themaxilla and the alignment of both upper and lowerteeth had been accomplished before the operation.

After a bilateral circumvestibular incision is per-formed, extending to the zygomaticomaxillary but-tress, the periosteum is elevated and the entire ante-rior and lateral maxillary walls are exposed. Thedissection is extended through the apertura piriformisto the medial wall of the maxilla. The broad exposurepermits excellent visualization of all osteotomies andenhances the manipulation of the bone during down-fracture. The osteotomy lines are designed classicallyat the pterygomaxillary junction and lateral wall of themaxilla; however, the line is elevated just inferior tothe infraorbital foramen at the anterior part. Afterosteotomy, the maxilla is gently down-fractured toprotect segments against vertical fracture or detach-ment. If the patient has bilateral cleft, the anteriormucosal flap of the premaxilla is kept intact to protectthe premaxilla from vascular impairment and the pre-maxilla is detached from the vomer by means of a5-mm chisel. After mobilization of the maxilla, themucosa is closed with an absorbable suture and thehalo frame (RED I; KLS Martin, Tuttlingen, Ger-many) is mounted to the patient’s skull. The os-teotomized and mobilized maxillary segment is an-chored to the tooth-borne orthodontic appliance,

Table 1. PATIENT CHARACTERISTICS

Case No. Gender Diagnosis Age (yr)Follow-Up at

Operation (mo)

1 F UCLP 22 11.02 F BCLP 25.1 8.03 M BCLP 18 3.04 M UCLP 23.30 7.05 M BCLP 19.30 5.06 F BCLP 16 3.07 F UCLP 24 9.08 F UCLP 21.6 6.09 M BCLP 30.6 11.0

10 M UCLP 32 5.011 F BCLP 25 28.012 F UCLP 17 4.513 M BCLP 23 9.014 F UCLP 21 3.0

Abbreviations: BCLP, bilateral cleft lip and palate; F, female;M, male; UCLP, unilateral cleft lip and palate.

Aksu et al. Pharyngeal Airway Changes After Distraction. J OralMaxillofac Surg 2012.

e134 PHARYNGEAL AIRWAY CHANGES AFTER DISTRACTION

which allows the distraction segment to follow thecurvature of the maxillary arch.

After a latency period of 5 days, active distraction at1 mm/d is started and continued until the desired skel-etal and dental relationships are clinically achieved. Dur-ing the consolidation period of 12 weeks, the distrac-tor and its intraoral appliance are kept in place andintraoral guiding elastics are used. After removal ofthe distractor and intraoral appliance, the patientskeep using intraoral elastics for another 6 weeks toestablish the final occlusion.

CEPHALOMETRIC EXAMINATIONLateral cephalograms were obtained preoperatively

(T1) and at short-term follow-up (T2) (8.0 ! 6.4months). Skeletal and pharyngeal airway changes ofthe maxilla were measured on the lateral cephalo-grams taken at 2 time intervals. To eliminate measure-ment errors, the same clinician (M.A.) made the lat-eral cephalometric tracings and measurements andconfirmed the measurement points.

Cephalometric variables representing skeletal pat-tern before treatment (T1) and after surgery (T2)were assessed by Ricketts’ cephalometric analysis.16

Analysis of the pharyngeal airway size was based onthe method of Mochida et al.7 Skeletal and pharyngealairway size measurements are presented in Figures 1A and 1B, respectively.

STATISTICAL ANALYSISThe mean, standard deviation, and minimum/max-

imum values were calculated for each cephalometricvariable. Changes in cephalometric variables after dis-traction were statistically evaluated by use of theWilcoxon signed-rank test with significance levels ofP " .05, P " .01, and P " .001. Spearman ! correla-tion was performed to check the correlations be-tween maxillary skeletal and pharyngeal variables. To

FIGURE 1. A, Skeletal measurements. 1, McNamara value (inmillimeters), shortest linear distance between point A and McNa-mara vertical; 2, maxillary depth angle (in degrees), angle be-tween Frankfort horizontal plane and NA plane; 3, effective max-illary length (in millimeters), distance between Co and A; 4,maxillary height angle (in degrees), angle between lines Na-CF-A;5, palatal plane angle (in degrees), angle between Frankfort hor-izontal plane and palatal plane; 6, ANS-FH (in millimeters), dis-tance between ANS and Frankfort horizontal plane; 7, ANS-PTV(in millimeters), distance between ANS and pterygoid verticalplane; 8, PNS-FH (in millimeters), distance between PNS andFrankfort horizontal plane; 9, PNS-PTV (in millimeters), distancebetween PNS and pterygoid vertical plane; 10, FMA (in degrees),angle between Frankfort horizontal plane and mandibular plane;11, lower facial height (in degrees), angle between lines ANS-XI-Pm; 12, overjet (in millimeters), horizontal distance between incisaledges of maxillary and mandibular incisors; 13, overbite (in milli-meters), vertical distance between incisal edges of maxillary andmandibular incisors. B, Pharyngeal airway measurements. 1, PAS(in millimeters), anteroposterior depth of pharynx measured be-tween posterior pharyngeal wall and PNS on a line parallel toFrankfort horizontal plane that runs through PNS; 2, SPAS (inmillimeters), anteroposterior depth of pharynx measured betweenposterior pharyngeal wall and dorsum of soft palate on a lineparallel to Frankfort horizontal plane that runs through middle of aline from PNS to P (P, tip of soft palate); 3, MAS (in millimeters),anteroposterior depth of pharynx measured between posterior pha-ryngeal wall and dorsum of tongue on a line parallel to Frankforthorizontal plane that runs through P; 4, inferior airway space (IAE)(in millimeters), anteroposterior depth of pharynx measured be-tween posterior pharyngeal wall and surface of tongue on a lineparallel to Frankfort horizontal plane that runs through most antero-inferior point on body of second cervical vertebra (C2); 5, epiglot-tic airway space (EAS) (in millimeters), anteroposterior depth ofpharynx measured between posterior pharyngeal wall and surfaceof tongue on a line parallel to Frankfort horizontal plane that runsthrough tip of epiglottis (E); 6, soft palate height (PNS-P) (in milli-meters), distance between PNS and P; 7, soft palate width (MPT),anteroposterior width of soft palate that runs through midpoint ofline constructed between PNS and P (soft palate axis); 8, softpalate–palatal plane angulation (PNSP-PP) (in degrees), angle be-tween soft palate axis and line constructed between ANS and PNS(palatal plane); 9, soft palate–Frankfort horizontal plane angula-tion (PNSP-FH) (in degrees), angle between soft palate axis andFrankfort horizontal plane.Aksu et al. Pharyngeal Airway Changes After Distraction. J OralMaxillofac Surg 2012.

AKSU ET AL e135

assess the accuracy of the method, 15 randomly se-lected cephalograms were retraced and recalculatedby the same investigator. The reliability coefficientswere between 0.92 and 0.94 for linear measures andbetween 0.93 and 0.98 for angular measures, indicat-ing a high level of consistency.

ResultsTable 2 shows the skeletal changes in CLP patients

from T1 to T2, as well as the results of the Wilcoxontest of changes from T1 to T2. Parameters regarding

the sagittal maxillary position (McNamara value, max-illary depth angle, effective maxillary length, and max-illary height angle) showed that anterior maxillarymovement was significant (P " .01 and P " .05). TheMcNamara value and effective maxillary length in-creased by 8.7 mm (96%) and 9.4 mm (11%), respec-tively. The palatal plane angle, distance between an-terior nasal spine and Frankfort horizontal plane, anddistance between posterior nasal spine and Frankforthorizontal plane showed a stable position (P $ .05),indicating a parallel anterior movement of the maxilla.ANS–pterygoid vertical plane (PTV) and PNS-PTV

Table 2. CEPHALOMETRIC VARIABLES REPRESENTING SKELETAL PATTERN BEFORE TREATMENT AND AFTERSURGERY AND THEIR DIFFERENCES (T2 – T1)

Variable Mean SD Range T2 – T1 % Change Significance P Value

McNamara value (mm)T1 %8.4 4.9 %17.0 to %2.0 #8.7 96 * .002T2 0.3 6.1 %11.0 to 10.0

Maxillary depth angle (°)T1 82.2 5.4 71.0 to 88.0 #7.9 9.6 * .001T2 90.1 5.2 78.0 to 98.0

Effective maxillary length (mm)T1 82.6 7.1 70.0 to 96.0 #9.4 11 * .001T2 92.0 6.9 80.0 to 105.0

Maxillary height angle (°)T1 62.5 5.6 54.0 to 74.0 #4.6 7 † .013T2 57.1 6.2 43.0 to 64.0

Palatal plane angle (°)T1 %1.4 6.2 %13.0 to 9.0 %1.2 86 NS .258T2 %2.6 7.9 %19.0 to 8.0

ANS-FH (mm)T1 24.9 7.6 8.0 to 43.0 %0.8 3 NS .598T2 24.1 7.1 6.0 to 33.0

ANS-PTV (mm)T1 54.9 6.0 43.0 to 67.0 #8.2 15 * .001T2 63.1 5.9 55.0 to 74.0

PNS-FH (mm)T1 25.4 4.2 20.0 to 33.0 #0.9 4 NS .326T2 26.3 6.0 17.0 to 35.0

PNS-PTV (mm)T1 5.7 3.3 0 to 10.0 #6.9 121 * .004T2 12.6 5.7 3.0 to 22.0

FMA (°)T1 31.0 5.1 25.0 to 42.0 0 0 NS .937T2 31.0 5.8 21.0 to 38.0

Lower facial height (°)T1 50.7 4.9 44.0 to 60.0 %1.0 1.9 NS .095T2 49.7 5.2 43.0 to 60.0

Overjet (mm)T1 %10.4 3.1 %16.0 to %5.0 #9.5 91 * .001T2 1.9 3.7 %3.0 to 10.0

Overbite (mm)T1 %1.6 4.1 %12.0 to 4.0 %1.4 88 NS .665T2 %3.0 9.9 %35.0 to 4.0

Abbreviations: ANS-FH, distance between ANS and Frankfort horizontal plane; FMA, angle between Frankfort horizontal planeand mandibular plane; NS, not significant; PNS-FH, distance between PNS and Frankfort horizontal plane.

*P " .01.†P " .05.

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e136 PHARYNGEAL AIRWAY CHANGES AFTER DISTRACTION

showed significant increases, supporting maxillary an-terior movement (8.2 mm [15%] and 6.9 mm [121%],respectively; P " .01). The parameters regarding thefacial height (angle between Frankfort horizontalplane and mandibular plane, as well as lower facialheight) did not show statistically significant differ-ences (P $ .05). Overjet increased significantly (9.5mm [91%], P " .01), whereas overbite did not showany significant change (P $ .05).

Table 3 shows the measurements of the pharyngealairway size at T1 and T2, as well as the results of theWilcoxon test of changes from T1 to T2. Changes inthe linear measurements between T1 and T2 showedsignificant increases in posterior airway space (PAS)(7.5 mm [31%]), superoposterior airway space (SPAS)(5.1 mm [32%]), and middle airway space (MAS) (3.3mm [30%]) (P " .01). Inferior airway space, epiglotticairway space, soft palate height and soft palate widthdid not change after distraction (P $ .05). The angularmeasurements—soft palate–palatal plane angulation(6.3° [5%]) and soft palate–Frankfort horizontal planeangulation (6.3° [4.9%])—were significantly different(P " .01).

Bivariate correlations are given in Table 4. Maxillaryskeletal variables showing the maxillary anteroposte-rior movement were significantly positively corre-lated with PAS and SPAS. Inferior airway spaceshowed a significant correlation with only PNS-PTV.The strongest correlations for PAS and SPAS were alsowith PNS-PTV. Stronger correlations with maxillaryskeletal variables were found for PAS than SPAS.

DiscussionIt has been reported in the literature that subjects

with upper airway obstruction gained airway suffi-ciency after distraction osteogenesis in the max-illa.7,17 Mochida et al7 reported significant airwaychanges in CLP patients after a mean of 12.4 mm ofmaxillary advancement. Xu et al,17 who measured thepharyngeal airway volume in syndromic patients,found significant enlargement of the upper airway(64.4%) after a mean of 20 mm of midface advance-ment. Jakobsone et al18 showed a 13% to 21% increasein airway dimension at the nasopharyngeal levelwhen the maxillary advancement surgery was per-

Table 3. CEPHALOMETRIC VARIABLES REPRESENTING PHARYNGEAL AIRWAY SIZE BEFORE TREATMENT AND AFTERSURGERY AND THEIR DIFFERENCES (T2 – T1)

Variable Mean SD Range T2 – T1 % Change Significance P Value

PAS (mm)T1 24.4 5.7 17.0 to 37.0 #7.5 31 * .003T2 31.9 4.7 24.0 to 40.0

SPAS (mm)T1 16.1 7.4 8.0 to 37.0 #5.1 32 * .003T2 21.2 6.6 9.0 to 35.0

MAS (mm)T1 11.1 3.8 4.0 to 18.0 #3.3 30 * .004T2 14.4 4.7 5.0 to 20.0

IAS (mm)T1 12.5 5.0 5.0 to 21.0 %0.3 2.4 NS .844T2 12.2 4.2 6.0 to 21.0

EAS (mm)T1 9.1 3.5 4.0 to 16.0 %1.0 11 NS .398T2 8.1 2.0 5.0 to 12.0

PNS-P (mm)T1 30.2 1.6 28.0 to 33.0 #1.0 3.3 NS .153T2 31.2 2.2 28.0 to 36.0

MPT (mm)T1 9.9 1.4 7.0 to 12.0 %0.7 7 NS .055T2 9.2 1.7 6.0 to 12.0

PNSP-PP (°)T1 132.1 10.3 114.0 to 151.0 #6.3 5 * .005T2 138.4 9.1 118.0 to 155.0

PNSP-FH (°)T1 129.6 7.8 113.0 to 142.0 #6.3 4.9 * .003T2 135.9 7.1 122.0 to 150.0

Abbreviations: EAS, epiglottic airway space; IAS, inferior airway space; MPT, soft palate width; NS, not significant; PNS-P,soft palate height; PNSP-FH, soft palate–Frankfort horizontal plane angulation; PNSP-PP, soft palate–palatal planeangulation.

*P " .01.

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AKSU ET AL e137

formed. The amount of maxillary advancement in ourstudy was 8.7 mm at the A point (McNamara value),representing a significant anterior maxillary move-ment. A mean 30% increase of the pharyngeal airwayspace at the level of PAS, SPAS, and MAS occurredafter distraction. The effect of maxillary advancementon pharyngeal airway diminished toward the lowerparts of the pharynx. As a result, the anteroposteriordimension of the superior and middle part of theupper airway length increased, and inferior part ofthe upper airway length remained stable in associa-tion with maxillary distraction osteogenesis. Thesefindings might suggest that there is a critical relation-ship between the anatomic structures of the PAS andSPAS and maxillary distraction.

In this study significant relationships were detectedin maxillary skeletal movement and pharyngeal air-way. The highest positive correlation found was be-tween the PAS and PNS-PTV, which accounted for r &0.92. Significant positive correlations were also ob-served for the PAS and McNamara value, maxillarylength, effective maxillary length, and ANS-PTV (r &0.78, r & 0.75, r & 0.77, and r & 0.66, respectively).SPAS also correlated positively with the maxillary vari-ables, less strongly than PAS. The findings of thisstudy suggest that the PAS follows the movement ofthe posterior bony structure of the maxilla with dis-traction osteogenesis. However, the SPAS and MASare defined as the length of lines constructed by 2landmarks on the soft tissue, which are far from thePNS. Therefore it is plausible that both the SPAS andMAS did not necessarily follow the movement of thebony structure.

Growth of the upper airway occurs predominantlyduring ages 0 to 5 years and ages 12 to 16 years,corresponding to periods of significant somaticgrowth.19 One of the main and most important find-ings reported in the study by Ronen et al20 was thatthere was a marked age-dependent difference in up-per airway length. Abramson et al19 also showed that

parameters of upper airway size correlated with age.The study by Mochida et al7 reported significant mor-phologic changes and an augmentation of the upperairway. However, they emphasized that the results oftheir study should be interpreted with caution be-cause the group examined was a mixed sample of CLPpatients, with variations in age. It is important toselect subjects who have completed maxillofacialgrowth to evaluate the changes by distraction treat-ment because both facial and airway structures keepgrowing during puberty. The patients in this studyhad a mean age of 22.7 years (SD, 4.6 years) at T1.Therefore it was considered that the growth of themaxillary bone and pharyngeal airway morphologywas completed and the subjects were appropriate formorphologic evaluation without any growth bias.19-23

Although a lateral cephalometric radiograph pro-vides only a 2D image of the pharyngeal airway, manyreports examining pharyngeal airway size rely on lat-eral cephalometrics.14,24-27 The advantages of a ceph-alometric analysis include its wide availability, sim-plicity, low expense, and ease of comparison withextensive normative data and other studies.28 Further-more, good correlation between airway dimensionsmeasured on lateral cephalometric radiographs andon 3D computed tomography was reported,29 validat-ing the usefulness of cephalograms in airway sizeanalysis.

The follow-up period in this study ranged between3 and 25 months. Many studies have been performedto assess time-dependent pharyngeal airway changesafter orthognathic surgery. Hochban et al13 reportedthat no significant changes in pharyngeal dimensionscould be seen on cephalometric follow-up at 3months and at 1 year, as compared with the 1-weekpostoperative situation. Kawakami et al30 suggestedthat 1 month after surgery was adequate to let thepostoperative swelling in the soft tissue settle.

The increases in soft palate–palatal plane angula-tion and soft palate–Frankfort horizontal plane angu-

Table 4. SPEARMAN CORRELATION COEFFICIENTS FOR PHARYNGEAL AIRWAY SIZES COMPARED WITHMAXILLARY SKELETAL VARIABLES

Spearman !

McNamara Value Maxillary DepthEffective Maxillary

Length ANS-PTV PNS-PTV

PAS 0.78* 0.75* 0.77* 0.66† 0.92*SPAS 0.59† 0.47 0.66† 0.57† 0.70*MAS 0.30 0.22 0.39 0.40 0.39Inferior airway space 0.45 0.38 0.26 0.46 0.61†

Epiglottic airway space 0.24 0.31 0.13 0.25 0.24

!P " .01.†P " .05.

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e138 PHARYNGEAL AIRWAY CHANGES AFTER DISTRACTION

lation resulted from the significant anterior move-ment of PNS. On the other hand, the measurements ofsoft palate height and soft palate width did not showsignificant changes from T1 to T2. The results suggestthat, after distraction, the morphology of the softpalate of cleft palate patients did not change, and thusthe operated soft palate kept its predistraction mor-phology. The gradual decrease in the increase of theSPAS and MAS might result from the change of thesoft palate position rather than structure, showingthat the anterior movement of the most inferior pointof the soft palate was less than the midpoint of thesoft palate. In contrast to our findings, adaptivechanges in the soft palate morphology were sug-gested to occur to preserve the oropharyngealseal.31-34 Anterior movement of the soft palate, partic-ularly in individuals who already have velar deficien-cies, may give rise to VP insufficiency by increasingthe anterior-posterior dimension of the nasopharynx.Witzel and Munro35 and Maegawa et al36 suggested acutoff point of 10 mm for conventional osteotomybefore observing any negative impact on VP function.Harada et al14 suggested a cutoff point of 15 mm fordistraction osteogenesis. The mean advancement of themaxilla in our study was 8.7 mm. However, the studywas conducted on cephalometric radiographs, and thepatients were not evaluated in terms of VP function;therefore any risk of deterioration on VP functionshould be considered cautiously.

The significant anterior movement of the maxilla re-sulted in significant increases in PAS, SPAS, and MAS.PAS, SPAS, and MAS increased by 7.5 mm, 5.1 mm, and3.3 mm, respectively. The soft palate also moved signif-icantly anteriorly, with the greatest movement at itssuperior point. The movement of PNS was 6.9 mm. Thehighest positive correlation found was between the PASand PNS-PTV. Significant positive correlations were alsoobserved for the PAS and maxillary skeletal variables.SPAS also correlated positively with the maxillary vari-ables, less strongly than PAS.

References1. Erbe M, Stoelinga PJ, Leenen RJ: Long-term results of segmental

repositioning of the maxilla in cleft palate patients withoutpreviously grafted alveolo-palatal clefts. J CraniomaxillofacSurg 24:109, 1996

2. Hirano A, Suzuki H: Factors related to relapse after Le Fort Imaxillary advancement osteotomy in patients with cleft lip andpalate. Cleft Palate Craniofac J 38:1, 2001

3. Houston WJ, James DR, Jones E, et al: Le Fort I maxillaryosteotomies in cleft palate cases. Surgical changes and stability.J Craniomaxillofac Surg 17:9, 1989

4. Posnick JC, Dagys AP: Skeletal stability and relapse patternsafter Le Fort I maxillary osteotomy fixed with miniplates: Theunilateral cleft lip and palate deformity. Plast Reconstr Surg94:924, 1994

5. Thongdee P, Samman N: Stability of maxillary surgical move-ment in unilateral cleft lip and palate with preceding alveolarbone grafting. Cleft Palate Craniofac J 42:664, 2005

6. Aksu M, Saglam-Aydinatay B, Akcan CA, et al: Skeletal anddental stability after maxillary distraction with a rigid externaldevice in adult cleft lip and palate patients. J Oral MaxillofacSurg 68:254, 2010

7. Mochida M, Ono T, Saito K, et al: Effects of maxillary distractionosteogenesis on the upper-airway size and nasal resistance insubjects with cleft lip and palate. Orthod Craniofac Res 7:189,2004

8. Kummer AW, Strife JL, Grau WH, et al: The effects of Le Fort Iosteotomy with maxillary movement on articulation, reso-nance, and velopharyngeal function. Cleft Palate J 26:193, 1989

9. Walker DA, Turvey TA, Warren DW: Alterations in nasal respi-ration and nasal airway size following superior repositioning ofthe maxilla. J Oral Maxillofac Surg 46:276, 1988

10. Chen F, Terada K, Hua Y, et al: Effects of bimaxillary surgeryand mandibular setback surgery on pharyngeal airway measure-ments in patients with Class III skeletal deformities. Am JOrthod Dentofacial Orthop 131:372, 2007

11. Saitoh K: Long-term changes in pharyngeal airway morphologyafter mandibular setback surgery. Am J Orthod DentofacialOrthop 125:556, 2004

12. Liukkonen M, Vähätalo K, Peltomäki T, et al: Effect of mandib-ular setback surgery on the posterior airway size. Int J AdultOrthodon Orthognath Surg 17:41, 2002

13. Hochban W, Schürmann R, Brandenburg U, et al: Mandibularsetback for surgical correction of mandibular hyperplasia—Does it provoke sleep-related breathing disorders? Int J OralMaxillofac Surg 25:333, 1996

14. Harada K, Ishii Y, Ishii M, et al: Effect of maxillary distractionosteogenesis on velopharyngeal function: A pilot study. OralSurg Oral Med Oral Pathol Oral Radiol Endod 93:538, 2002

15. Jeans WD, Fernando DC, Maw AR, et al: A longitudinal study ofthe growth of the nasopharynx and its contents in normalchildren. Br J Radiol 54:117, 1981

16. Ricketts RM, Bench RW, Gugino CF, et al: BioprogressiveTherapy. Denver, CO, Rocky Mountain Orthodontics, 1980

17. Xu H, Yu Z, Mu X: The assessment of midface distractionosteogenesis in treatment of upper airway obstruction. JCraniofac Surg 20:1876, 2009 (suppl 2)

18. Jakobsone G, Stenvik A, Espeland L: The effect of maxillaryadvancement and impaction on the upper airway after bimax-illary surgery to correct Class III malocclusion. Am J OrthodDentofacial Orthop 139:e369, 2011

19. Abramson Z, Susarla S, Troulis M, et al: Age-related changes ofthe upper airway assessed by 3-dimensional computed tomog-raphy. J Craniofac Surg 20:657, 2009 (suppl 1)

20. Ronen O, Malhotra A, Pillar G: Influence of gender and age onupper-airway length during development. Pediatrics 120:e1028, 2007

21. Handelman CS, Osborne G: Growth of the nasopharynx andadenoid development from one to eighteen years. Angle Or-thod 46:243, 1976

22. Linder-Aronson S, Leighton BC: A longitudinal study of thedevelopment of the posterior nasopharyngeal wall between 3and 16 years of age. Eur J Orthod 5:47, 1983

23. McNamara JA Jr: A method of cephalometric evaluation. Am JOrthod 86:449, 1984

24. Legan HL, Burstone CJ: Soft tissue cephalometric analysis fororthognathic surgery. J Oral Surg 38:744, 1980

25. Ozbek MM, Miyamoto K, Lowe AA, et al: Natural head posture,upper airway morphology and obstructive sleep apnoea sever-ity in adults. Eur J Orthod 20:133, 1998

26. Solow B, Siersbaek-Nielsen S, Greve E: Airway adequacy, headposture, and craniofacial morphology. Am J Orthod 86:214,1984

27. Lowe AA, Takada K, Yamagata Y, et al: Dentoskeletal andtongue soft-tissue correlates: A cephalometric analysis of restposition. Am J Orthod 88:333, 1985

28. Miles PG, O’Reilly M, Close J: The reliability of upper airwaylandmark identification. Aust Orthod J 14:3, 1995

29. Lowe AA, Fleetham JA, Adachi S, et al: Cephalometric andcomputed tomographic predictors of obstructive sleepapnea severity. Am J Orthod Dentofacial Orthop 107:589,1995

AKSU ET AL e139

30. Kawakami M, Yamamoto K, Fujimoto M, et al: Changes in tongueand hyoid positions, and posterior airway space following man-dibular setback surgery. J Craniomaxillofac Surg 33:107, 2005

31. Heliövaara A, Hukki J, Ranta R, et al: Cephalometric pharyngealchanges after Le Fort I osteotomy in different types of clefts.Scand J Plast Reconstr Surg Hand Surg 38:5, 2004

32. Greco JM, Frohberg U, Van Sickels JE: Cephalometric analysisof long-term airway space changes with maxillary osteotomies.Oral Surg Oral Med Oral Pathol 70:552, 1990

33. Turnbull NR, Battagel JM: The effects of orthognathic surgery

on pharyngeal airway dimensions and quality of sleep. J Orthod27:235, 2000

34. Schendel SA, Oeschlaeger M, Wolford LM, et al: Velopharyn-geal anatomy and maxillary advancement. J Maxillofac Surg7:116, 1979

35. Witzel MA, Munro IR: Velopharyngeal insufficiency after max-illary advancement. Cleft Palate J 14:176, 1977

36. Maegawa J, Sells RK, David DJ: Speech changes after maxillaryadvancement in 40 cleft lip and palate patients. J CraniofacSurg 9:177, 1998

e140 PHARYNGEAL AIRWAY CHANGES AFTER DISTRACTION