Abstract
Objective
The aim of this study is to evaluate the nasopharyngeal airway volumes of patients with unilateral cleft lip and palate (UCLP) with different GOSLON scores.
Methods
The study sample consisted of 34 patients with UCLP and 20 controls with no cleft history. In the UCLP group, three experienced examiners used the GOSLON Yardstick to rate dental arch relationships, and the sample was divided into three groups as GOSLON 2 (G2) (n = 13), GOSLON 3 (G3) (n = 10), and GOSLON 4 (G4) (n = 11). Airway volumes were constructed using three-dimensional computed tomography data and divided into four compartments named the nasal airway, and superior, middle, and inferior pharyngeal airways.
Results
No statistically significant difference was detected among G2, G3, and G4 between the constitutive airway departments of the nasopharyngeal region. However, nasal airway volumes were significantly higher in the control group when compared with the UCLP group.
Discussion
Although there was no correlation among the investigated parameters, it is also a fact that airway capacities display a great variability among patients when investigated three dimensionally.
Conclusion
Although the severity of GOSLON scores might predetermine the extent of which the airways are affected from the cleft, a larger sample size is needed in future studies.
Keywords
Patients with cleft lip and palate (CLP) appear with several problems concerning not only the oral structure but the neighboring regions also. Due to dysmorphology of the columella, nasal tip, alar cartilage, nasal sill; deviations and hypoplasia of the skeletal nasal base (Huffman and Lierle, 1949; Bardach and Cutting, 1990); and deficiencies concerning three dimensions of the maxilla, nasal resistance is met with snoring and respiratory difficulties (Warren et al., 1969; Bardach and Cutting, 1990; Trindade et al., 2009).
The problems of maxillary growth are reflected in sagittal, vertical, and transversal dental arch relationships. Though clinicians have devised different techniques (Huddart-Bodenham, 1972; Morris et al., 1994; Atack et al., 1997) of assessing intercenter scores of dental arch relationships, the pioneering method of Mars et al. (1987) remains to be the method used most often for predicting the degree of malocclusion (Hathaway et al., 2011; Dogan et al., 2012), reflection of orthodontic treatment results (Love et al., 2012; Southall et al., 2012), and evaluation of surgical outcomes (Fudalej et al., 2009; Offert et al., 2012). Even though the system was initially developed for late mixed and early permanent dentition, Noverraz et al. (1993) pointed out that GOSLON Yardstick is applicable to all stages of dental development and is suitable for longitudinal research (Hsieh et al., 2012).
The most frequently used two-dimensional (2D) diagnostic methods of orthodontics—namely cephalometrics and posteroanterior roentgenograms—to access airway capacity have flows of magnification, landmark identification, and reproducibility (Lowe and Fleetham, 1991; Lowe et al., 1995). However, it is not always convenient to have thorough tomography scan of each cleft patient, and some patients do not have access to advanced health services. Therefore, a method that is easier, cheaper, and more convenient for the reach of every patient, which also provides the clinicians with the overall picture concerning the airways, could be more advantageous in everyday clinic life.
Our objective is to evaluate the nasopharyngeal airway volumes of patients with unilateral cleft lip and palate (UCLP) with different GOSLON scores to help clinicians differentiate cleft patients according to their respiratory needs based on their GOSLON scores. This is the first study in the literature to interrogate the relationship between GOSLON Yardstick and pharyngeal airways.
Methods
The study sample consisted of 34 patients with UCLP (16 girls and 18 boys) and 20 controls (9 girls, 11 boys) with no cleft history. The ages ranged between 13 and 15 years (mean, 14.3 ± 0.4 years and 14.0 ± 0.9 years for the cleft and control patients, respectively) for both groups. The inclusion criteria were absence of any syndromes and any symptoms due to upper airway infections and pharyngeal pathologies such as adenoid vegetation and tonsillitis. The computed tomography (CT) scans of the control group were acquired from patients with no respiratory complaint and who had already undergone CT scanning for the evaluation of the effects of rapid maxillary expansion. This sample was also used in a previous study to compare the efficacy of 2D and 3D diagnostic methods of UCLP patients (Aras et al., 2012). The principles outlined in the Declaration of Helsinki were followed.
In CT evaluation, borders for nasal, superior, middle, and inferior airway identifications were based on an airway research, since in the preceding study the method used was said to introduce minimum bias and provide ease in determining the landmarks (Kim et al., 2010). Frankfort horizontal plane (FHP) was constructed on the 3D images using bilateral porion points and the lowest border of orbita. Even though the FHP was not perpendicular to the long axis of the airways, this plane is being used routinely to standardize the orientation of the other used planes. Porion, lower border of orbita, anterior nasal spine, posterior nasal spine, caudal border of soft palate, and superior border of epiglottis were used in determining the borders of the airways. This volume was divided into four compartments as nasal airway, and superior, middle, and inferior pharyngeal airways (Fig. 1).
A: Three parallel axial and two perpendicular frontal planes used for 3D analysis. B: Cephalometric radiograph showing axial and perpendicular planes. FH plane (Frankfort horizontal plane), plane between porion point and the lowest border of orbita; Ana plane (anterior nasal plane), frontal plane perpendicularly intersecting the FHP at ANS point; Pna plane (posterior nasal plane), frontal plane perpendicularly intersecting the FHP at PNS point; Uph plane (upper pharyngeal plane), axial plane parallel to FHP passing through PNS point; Mph plane (middle pharyngeal plane), axial plane parallel to FHP passing through the caudal border of the soft palate; Lph plane (lower pharyngeal plane), axial plane parallel to FHP passing through the superior border of epiglottis.
Three experienced examiners used the GOSLON Yardstick to rate dental arch relationships. The classification of Mars et al. (1987) was used. The original classification included five categories as described below:
Group 1: Positive overjet with average inclined or retroclined incisors with no crossbite or open bite. Longterm outcome: excellent.
Group 2: Positive overjet with average inclined or proclined incisors with unilateral crossbite or crossbite tendency with or without open bite tendency around cleft site. Longterm outcome: good.
Group 3: Edge-to-edge bite with average inclined or proclined incisors or reverse overjet with retroclined incisors. Unilateral crossbite with or without open bite tendency around cleft site. Longterm outcome: fair.
Group 4: Reverse overjet with average inclined or proclined incisors. Unilateral crossbite with or without bilateral crossbite tendency with or without open bite tendency around cleft site. Longterm outcome: poor.
Group 5: Reverse overjet with proclined incisors, bilateral crossbite, and poor maxillary arch form and palatal vault anatomy. Longterm outcome: very poor.
However, the overall sample in the present study presented with only three subgroups, namely G2 (n = 13; 6 girls and 7 boys), G3 (n = 10; 3 girls and 7 boys), and G4 (n = 11; 7 girls and 4 boys) as derived from the scores of examiners.
Linear weighted kappa was used to determine the interrater agreement, while Kruskal-Wallis analysis was utilized to determine the correlation between the GOSLON scores and airway volumes, and Mann-Whitney U test was used for the discernment among groups and to determine the difference between the controls and cleft subjects.
Results
The kappa score between examiners 1 (S.O.G.) and 2 (I.A.) was 0.907, while it was 0.906 for examiners 1 (S.O.G.) and 3 (S.D.) and 0.872 for examiners 2 and 3, meaning interrater agreement was very good.
Table 1 shows the volumetric data of UCLP patients and control group. The nasal airway volumes of patients with UCLP were significantly smaller when compared with noncleft patients.
The Volumetric Data of Unilateral Cleft Lip and Palate (UCLP) Patients and Control Group
P ≤ .01.
Kruskal-Wallis analysis yielded statistically significant differences for only the nasal region. Thus, when the Mann-Whitney U test was executed for the discernment among groups, no statistically significant results were obtained among G2-G3, G2-G4, and G3-G4, while all the GOSLON subgroups revealed significant differences compared to the airways of controls (Table 2).
The Correlations Pertaining to Different GOSLON Scores and Control Group and Volumes of Airway Compartments
P < .05.
Discussion
The nasal airway volumes of patients with UCLP were significantly smaller when compared with noncleft patients. A total decrease in the nasal volumes of the patients with cleft may be an outcome of nasal deformities usually encountered in these patients. Similarly, Fukushiro and Trindade (2005) found smaller nasal areas in UCLP patients when compared with isolated cleft patients, though the difference was not statistically significant. Also, Warren et al. (1969) reported that nasal resistance in subjects with CLP is 20% to 30% higher than that in age-matched non-CLP subjects.
The Yardstick needs a learning curve, better together with a calibration course (Mars et al., 1987). Additionally, it is prone to introduce elements of subjectivity to the assessment as pointed out Mossey et al. (2003), which consequently led to the proposition of using reference models (Hathorn et al., 1996; Leonard et al., 1998; Nollet et al., 2005). The agreements between raters were excellent in the current study with no need of reference models. The disparities in a few casts were resolved by reaching a mutual agreement before carrying out the statistics concerning the relationship between GOSLON scores and airway volumes.
According to the Yardstick, the dental arch relationship is graded from 1 to 5, where a grade 1 means very good, 2 – good, 3 – fair, 4 – poor, and 5 – very poor dental arch relationship. In a patient graded 1 or 2, a straightforward orthodontic treatment is required; in a patient graded 3, complex orthodontic treatment is required; whereas a patient graded 4 or 5 requires orthognathic surgery (Offert el al., 2012). However, until now, no research was carried out investigating the relationship between GOSLON Yardstick and nasopharyngeal airway volume. According to the results of our study, the nasal airway capacities of cleft patients showed significantly constricted values when compared with the controls. These sets of data are in accordance with the study by Aras et al. (2012) in which the control group displayed larger volume values in the nasal compartment. Though the difference of GOSLON subgroups among each other was not significant, nasal airway volumes were largest among grade 2 patients who present with the mildest deformity, presumably due to the fact that GOSLON score 2 individuals were the set of patients displaying physiologic and morphologic traits closer to normal individuals. When middle and inferior nasopharyngeal dimensions are considered, the most intense deformities corresponded to largest volumetric sizes, with the values relatively similar to each other among GOSLON groups. These results are, in a way, confirmed by the research of Aras et al. (2012), which found that cleft patients displaying larger values compared to controls in middle and inferior airway compartments, supposedly as an act of compensation.
No correlation was found among the investigated parameters. However, it is also a fact that airway capacities display a great variability among patients when investigated three dimensionally (Aboudara et al., 2009). Furthermore, a clear-cut conclusion is not solely based on morphologic investigation but dependent upon functional airway resistance also (Warren, 1991), which is another shortcoming of the present study. Although it was observed that GOSLON scorings were not enough to draw a conclusion pertaining to nasopharyngeal airway volumes in this sample, a larger sample size could provide a more explicit provision among GOSLON scores and airway capacities.
Conclusion
Although the nasal airway volume in G2 was greater than that in G3 and G4, there were no significant differences among nasopharyngeal airway volumes corresponding to different GOSLON scores. A more thorough investigation with an increased sample size would provide more realistic facts concerning airway volume, which in its nature displays high variability among individuals.