|Year : 2014 | Volume
| Issue : 4 | Page : 297-303
Cephalometric evaluation of adenoids, upper airway, maxilla, velum length, need ratio for determining velopharyngeal incompetency in subjects with unilateral cleft lip and palate
Avinash Gohilot1, Tejashri Pradhan2, Kanhoba Mahabaleshwar Keluskar2
1 Department of Orthodontics, Aditya Birla Memorial Hospital, Pune, Maharashtra, India
2 Department of Orthodontics, KLE V.K Institute of Dental Sciences, Belgaum, Karanataka, India
|Date of Web Publication||17-Sep-2014|
Department of Orthodontics and Dentofacial Orthopedics, Aditya Birla Memorial Hospital, Pune - 411 033, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objectives: Children with cleft lip and palate (CLP) are seen to have reduced airway size and large adenoids, which might lead to different characteristics in the upper airway and surrounding tissues from both morphological and functional perspectives. Decrease in adenoid size and increase in need ratio in cleft patients might lead to velopharyngeal incompetency (VPI) and development of nasality in adulthood. No studies have been conducted on the Indian population with variables contributing to VPI. So the aim was to evaluate the size and position of the adenoids, upper airway, maxilla, velum length and need ratio contributing to VPI in subjects with and without unilateral cleft lip and palate (UCLP) during juvenile and adolescent stages. Materials and Methods: Cephalograms of 120 subjects with 6-17 years were taken and various linear and angular measurements were measured and data was analyzed using the unpaired t test. Results: Adenoids were significantly larger and the upper airway smaller in the juvenile and adolescent cleft group than in the non-cleft group. In the adolescent cleft group, airway was larger than that in the adolescent non-cleft group. The maxilla was small and retropositioned in juvenile and adolescent subjects as compared to non cleft cases. Length of velum was smaller and need ratio was larger in both juvenile and adolescent groups as compared to the non-cleft group, suggestive of velopharyngeal incompetence. Conclusion: Decreased Adenoids, restricted airway, small, retruded maxilla, smaller velum length and larger need ratio larger were seen in the cleft group as compared to the non-cleft group, which was suggestive of VPI.
Keywords: Adenoids, airway, UCLP, velum length, VPI
|How to cite this article:|
Gohilot A, Pradhan T, Keluskar KM. Cephalometric evaluation of adenoids, upper airway, maxilla, velum length, need ratio for determining velopharyngeal incompetency in subjects with unilateral cleft lip and palate. J Indian Soc Pedod Prev Dent 2014;32:297-303
|How to cite this URL:|
Gohilot A, Pradhan T, Keluskar KM. Cephalometric evaluation of adenoids, upper airway, maxilla, velum length, need ratio for determining velopharyngeal incompetency in subjects with unilateral cleft lip and palate. J Indian Soc Pedod Prev Dent [serial online] 2014 [cited 2019 Jul 24];32:297-303. Available from: http://www.jisppd.com/text.asp?2014/32/4/297/140950
| Introduction|| |
Adenoid is a hypertrophied lymphoepithelial tissue that comprises part of Waldeyer's pharyngeal ring and plays an important role in the immune system (Van Cauwenberge 1995).  It was reported that adenoids usually increase in size during childhood and involution occurs in adolescence with the growth of nasopharynx. Pathological symptoms are most common from 2 to 12 years of age (Linder Aronson 1970).  There is a contention that palatopharyngoplasty for patients with cleft lip and palate (CLP) produces maxillary growth deficiency, and many patients with CLP exhibit a skeletal Class III jaw relationship (Handelmann 1976).  Moreover, it has been reported that CLP patients have a reduced nasal airway compared to normal subjects, and the incompetent nasal airway predisposes CLP patients to oral breathing (Ren 1993).  The soft palate which is the posterior fibromuscular part of the palate that is attached to the posterior edge of the hard palate and participates in most oral functions may be affected by surgeries done at early age. Increase in nasopharyngeal depth and decrease in adenoid size in adolescence might compromise velopharyngeal closure and increase the need ratio (pharyngeal depth: Velum length) in cleft patients and lead to velopharyngeal incompetency (VPI) and development of nasality in adulthood. CLP patients might have different characteristics in the upper airway and its surrounding tissues than do normal subjects from both morphological and functional perspectives (Warren 1988).  No studies have been documented in Indian literature with regards to adenoids, airway, maxilla, and velum length and need ratio contributing to VPI. Hence, the aim of this study was to evaluate the two-dimensional size and position of the adenoidal tissue, upper airway, maxillary base, velum length and need ratio in determining VPI in subjects with and without unilateral cleft lip and palate (UCLP).
| Materials and Method|| |
The study was based on pre-orthodontic cephalograms of patients with UCLP coming KLE VK Institute of Dental Sciences Belgaum, Karnataka, India after an ethical review committee of the institute approved the study and that informed consent was obtained. Patients selected were those who had undergone V-Y pushback palatoplasty around 12-15 months of age and cleft lip repair around 4-5 months surgery. The sample consists of 120 subjects within the juvenile age group (6-12 years) and adolescent age group (13-17 years), 60 with UCLP comprising of 30 male and 30 female patients. Sixty subjects acted as the control group comprising of 30 males and 30 females. Patients with UCLP who have undergone pharyngoplasty and those whose radiographs were with poor resolution of reference points were not selected.
Tracings were made of the lateral cephalograms taken in the intercuspal position and were traced by the same person to avoid inter-examiner bias. Several linear, area, angular measurements along with ratios were determined to evaluate the sizes of the adenoidal tissue, upper airway, position along with size of maxillary base dimensions, velum length and need ratio. The various linear measurements and angular measurements are as follow
Linear measurement of adenoids: [Figure 1]a
T1- Thickness of soft tissue shadow (i.e. adenoidal tissues) on line from pterygomaxillary point (PMP, intersection of contours of nasal floor with posterior contours of maxilla) to midpoint of line joining Ba and S. T2- Thickness of adenoidal tissue on line from PMP to Ba.
Linear measurement of airway: [Figure 1]a
P1- Shortest distance from most anterior part of adenoidal mass to posterior wall of maxillary antrum. P2- Distance from PMP to adenoidal tissue along line from PMP to midpoint of line joining Ba and S. P3- Distance from PMP to the posterior pharyngeal wall along line from PMP to Ba. P4- Shortest distance from the upper surface of palatine velum to adenoidal tissue.
Nasopharyngeal area: [Figure 1]b
Total nasopharyngeal area was calculated within trapezoid consisting of four lines.
Line 1: Representing palatal plane passing most superior point on Dens Axis.
Line 2: Perpendicular to palatal plane tangent to anterior surfaces of Dens Axis.
Line 3: Perpendicular to palatal plane that intersects palatal plane at pterygomaxillary fissure.
Line 4: Tangent to lower border of sphenoid bone registered at Ba.
Area was then calculated using the formula
Adenoidal-nasopharyngeal ratios: [Figure 1]a
U2 - Intersection of anterior contour of adenoidal tissue and line crossing adenoidal tissue with shortest distance from PMP.
U2' - Intersection of sphenoid bone and extension of line connecting U2 and PMP.
U3 - Intersection of anterior contour of adenoidal tissue and line connecting Ba and PMP.
ANR - U2- Ratios of distance between U2 and U2' to distance between PMP and U2'.
ANR - Ba- Ratio of distance between U3 and Ba to distance between PMP and B.
Linear measurement of position of PMP: [Figure 1]a
v PMP - Distance between S and palatal plane.
h PMP - Distance between X (intersection of palatal plane and line perpendicular to palatal plane registered at S) and PMP.
Position and size of maxillary base: [Figure 1]a
M1 - Anterior nasal spine to posterior nasal spine.
M2-SNA (angle formed by sella-nasion and nasion - point A).
Linear measurement of length of velum and pharyngeal DEPTH: [Figure 1]a
V1 - linear distance from the pterygomaxillary point (PMP) to the tip of the uvula of the resting soft palate.
Need ratio is calculated by measuring the length of velum (V1) and pharyngeal depth at (P4).
The data gathered was stored and analyzed using the SPSS v. 15.0 statistical analysis program. Comparisons between variables of the cleft lip and palate group and the non-cleft group in the juvenile and adolescent group were done using the unpaired t test. Pearson correlation was performed between variables. The results were regarded as statistically significant at P < 0.05.
| Results|| |
In [Table 1] variables were compared in juvenile cleft and non-cleft groups where statistical significant difference was seen in adenoid size which was of increased size in the cleft group T1 (11.7 ± 3.2) compared to the non-cleft group (10.6 ± 5.2). Airway passage size was reduced in the cleft group P1 (5.08 ± 2.1), P2 (11.4 ± 3.9), P3 (15.1 ± 4.4) as compared to the non-cleft group P1 (7.13 ± 4.9), P2 (14.5 ± 4.4), P3 (18.3 ± 5.2). Adenoidal: Nasopharyngeal ratio at U2 was higher in the cleft juvenile group (0.4± 0.1) as compared to the non-cleft group (0.3 ± 0.1) and at Ba it was higher in the cleft group (0.5 ± 0.1) than in the non-cleft group (0.4 ± 0.08). Vertical and horizontal distance of PMP with respect to cranial base was less in the cleft group VPMP (35 ± 3.8), HPMP (17.4 ± 4) as compared to the non-cleft group VPMP (38.7 ± 2.9), HPMP (20.6 ± 3.4). Length of maxilla was smaller and retropositioned in the cleft juvenile group i.e. maxilla length (44.4 ± 4), SNA (74.9 ± 6.1) as compared to the non-cleft juvenile group i.e. length (48.1 ± 3.4), SNA (77.5 ± 1.8). Length of velum was smaller in cleft subjects (28.1 ± 4.9) as compared to non-cleft juvenile subjects i.e. (32.53 ± 3.38) and the need ratio was increased in cleft patient (0.3 ± 0.11) as compared to non-cleft juvenile patient which was (0.2 ± 0.08).
|Table 1: Comparison of group 1 (juvenile cleft) and group 3 (juvenile non-cleft)|
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[Table 2] compared variables in the adolescent cleft group with the adolescent non-cleft group statistical significant difference was seen in adenoid size at T1 (11.7 ± 3.9) was increased in the adolescent cleft group as compared to the non-cleft group (9.5 ± 3.7). Airway passage was increased in the adolescent cleft group at P4 (11.1 ± 4) as compared to the non-cleft group (8.4 ± 2.8). Nasopharyngeal area was increased in the non-cleft group (1161.04 ± 175.5) as compared to the cleft group (801.8 ± 284.4). Horizontal position of PMP with respect to cranial base was less in the cleft group (18.6 ± 4.3) as compared to the non-cleft group in adolescent. Length of maxilla was less in the cleft group (46.08 ± 3.7) as compared to the non-cleft group (52.9 ± 3.1) and maxilla was also retropositioned with respect to cranial base in the cleft adolescent group (73.03 ± 4.5) as compared to the non-cleft group (78.6 ± 2.5). Length of velum was less in the adolescent cleft group i.e. (28.03 4.8) as compared to the non-cleft adolescent group (34.1 ± 3.1) and need ratio was greater in the cleft group (0.4 ± 0.1) as compared to the non-cleft group (0.2 ± 0.1).
|Table 2: Comparison of group 2 (adolescent cleft) and group 4 adolescent non-cleft)|
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[Table 3] showed comparison between the juvenile cleft group and the adolescent cleft group and statistical significant difference was seen in adenoid size at T1 which was increased in the juvenile group (11.7 ± 3.2) as compared to the adolescent group (9.5 ± 3.7). Airway size was decreased in the juvenile cleft group at P1 (5.08 ± 2.1), P2 (11.4 ± 3.9), P4 (9.2 ± 2.6) compared to the adolescent cleft group P1 (6.3 ± 2.3), P2 (14.1 ± 3.9), P4 (11.1 ± 4). ANR-U2 ratio was increased in the juvenile cleft group (0.4 ± 0.1) than in non cleft juvenile group (0.3 ± 0.1) Vertical position of PMP with respect to cranial base was increased in when the adolescent group (37.8 ± 4.5) was compared to the juvenile cleft group (35.03 ± 3.8), need ratio was greater in the adolescent cleft group (0.4 ± 0.14) than in the juvenile cleft group (0.3 ± 0.1). No significant changes were seen in size and position of maxilla in the juvenile and adolescent cleft group.
|Table 3: Comparison between group 1 (juvenile cleft) and group 2 (adolescent cleft)|
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[Table 4] compared the juvenile non-cleft group with the adolescent non-cleft group and found that statistical significant relation was found in nasopharyngeal area that was increased in the adolescent non-cleft group i.e. (1161.04 ± 175.5) as compared with the juvenile non-cleft group i.e. (836.1 ± 170.3). There was increased length of maxilla in the adolescent non-cleft group (52.9 ± 3.1) as compared to the non-juvenile cleft group (48.1 ± 3.4). Maxilla was retropositioned with respect to cranial base in the non-juvenile group i.e. (77.5 ± 1.8) as compared to the adolescent non-cleft group (78.6 ± 2.5). Length of velum was greater in the adolescent non-cleft group (34.13 ± 3.19) as compared to the juvenile non-cleft group (32.5 ± 3.3).
|Table 4: Comparison between group 3 (Juvenile non cleft) and group 4 (Adolescent non cleft)|
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| Discussion|| |
The developmental growth of adenoid tissue is very quick and may take up one half of the nasopharyngeal space by 2-3 years of age  and the thickness of the soft tissue on the posterior wall is at a maximum at five years of age and successively reduces up to the age of ten and is sometimes as late as 14-15 years of age. Hypertrophy of the lymphoid tissue on the posterior nasopharyngeal wall causes problem in breathing especially during the preschool period and during early school years. Cleft lip and palate anomaly is one of the most frequently encountered congenital malformations. The defects usually associated with cleft lip and palate patients are those of growth in all three planes i.e. vertical, sagittal and transverse planes especially in sagittal plane.
Cleft patient presents more frequently with large adenoids than do the non-cleft population.  This has been regarded as a compensatory phenomenon to decrease the pharyngeal depth and make velopharyngeal competence possible. After palatal operation, soft tissue is sometime short and scarred and frequently the uvula is missing, tissue deficit result in incompetence to velopharyngeal sphincter mechanism.
Many authors accept that surgical repair of the cleft lip and palate has detrimental effects on midfacial growth in patients with UCLP. Controversy still remains as to whether the midfacial growth disturbance results more from the lip or from the palate repair. To our knowledge, few studies have compared the size of adenoidal tissue, upper airway passage but no study has been documented on size and position of maxilla, length of velum, need ratio and their contribution in VPI in subjects with CLP and normal and documented of these variables in Indian population.
Size of adenoidal tissues and upper-airway dimensions
In this study, there were significant differences in the thickness of adenoidal tissues, airway passage, nasopharyngeal area, adenoidal: Nasopharyngeal ratio between juvenile and adolescent cleft subjects as compared to normal subjects. It was noted that adenoidal tissue size was larger in the juvenile and adolescent cleft group as compared to the adolescent cleft group and airway passage was decreased in juvenile subjects. The thickness of adenoidal tissues decreases with age in both subjects with and without CLP. Conversely, the upper airway dimensions increase in those with and without CLP, leading to a decrease in ANRs in both groups. Nonetheless, the anteroposterior dimensions in the adolescents with CLP were still significantly narrower than those in the adolescent controls which is in accordance with the statement made in previous study by Imamura et al. 
We also found that statistical difference between ANR-U2 and ANR-Ba in juvenile subjects with CLP which was in accordance with previous study by Kemalogu et al. 
Size and position of maxilla
In this study, position and size of maxilla was assessed and it was found that maxilla is more retropositioned and was smaller in size in juvenile cleft subjects as compared to juvenile non-cleft subjects and continued to remain smaller and retruded in adolescent group stage which is in correlation with Chen  who concluded that sagittal growth of the maxilla appears to be inhibited in patients with isolated cleft palate, which became more severe with age. Various reasons have been put forward for short and retropositioned maxilla. Scar tissue is a primary etiological factor in maxillofacial growth dysplasias. Ross (1987) , evaluated maxillofacial growth with UCLP who had undergone palate repair with a number of different timings and concluded that postponing hard palate repair produced the most favorable growth results in both sagittal and vertical dimensions.
Horswell  evaluated craniofacial growth in UCLP patients and reported reduced maxillary arch length in cleft individuals. Blanco  also showed significant reduction in all the arch dimensions in cleft palate patients.
Gabriel et al. (1992)  in their study on the influence of cleft on maxillary arch morphology concluded that maxillary arch is distorted in the presence of cleft.
However, in contrast, Friede et al.  also found no difference in growth results whether palate repair occurred at 5 or 9 years and Rohrich et al.  found no growth differences in a long-term evaluation of adult patients with clefts having hard palate repairs at either 10 months or 4 years of age.
Vertical and horizontal position of pterygomaxillary point (PMP) with respect to cranial base was less in the cleft group both at juvenile and adolescent stage as compared to the non-cleft group .i.e. posterior height of maxilla was less in cleft patient as compared to non-cleft this was in agreement with Wada et al. who also found growth of the posterior maxilla in the CLP subjects was significantly less at any age in both the horizontal and vertical dimensions compared with that in the controls.
Length of velum and Need ratio
In our study we found that length of velum was shorter in the cleft group as compared to normal subjects and need ratio i.e. pharyngeal depth: Velum length was greater in the cleft group as compared to normal subjects suggesting that there is a high possibility of VPI in subjects with clefts which is in agreement with Hsin et al. who observed velopharyngeal dimensions and velopharyngeal in 58 patients with cleft lip and palate and concluded that pharyngeal depth, velar length, hard palate length and thickness of pharyngeal wall were contributing factor to velopharyngeal competency. And Lu  who concluded that the velopharyngeal morphology of adults with VPI is characterized by a shorter palate, greater need ratio. Therefore, it is a likely hypothesis that velopharyngeal adequacy is strongly dependent on a close coordination of the anatomic parts involved in velopharyngeal closure, the soft palate and the contiguous pharyngeal structures. Since the harmony of the velum and surrounding pharyngeal structures seems to be indispensable for velopharyngeal closure, it is reasonable to hypothesize that the contiguous pharyngeal structures may have different characteristics to match up to different velar morphologies.
Finally, a significant correlation was seen between each parameter. As the size of adenoids increase subsequent decrease in the airway passage, ANR was seen and as age progresses vice versa was seen. Also, a significant correlation was seen between velum length and need ratio, as velum length decreased, need ratio was greater suggestive of velopharyngeal incompetence.
Most previous morphological and functional studies in CLP subjects used mixed samples of various heterogeneous types of cleft (e.g., unilateral or bilateral CLP, unilateral or bilateral cleft lip and isolated cleft palate). So we evaluated these variables in UCLP subjects. It was also been reported that the nasopharyngeal size differs according to the cleft type.
We used the PMP instead of the posterior nasal spine because it is sometimes difficult to define the posterior nasal spine in subjects with CLP. Many different protocols for surgical intervention for unilateral CLP have been proposed, modified, and used. Some recommend early closure of lip and palate, emphasizing speech function, while others advocate delayed closure of the hard palate according to the growth of the maxilla.
Cleft palate patients should be evaluated by speech therapist on periodic basis through adolescence, even though they demonstrate normal velopharyngeal function at earlier ages. Alternatively, the family of such a patient can be advised to be alert for any changes in speech resonance during that period. Cleft subjects should be properly examined for velopharyngeal competency before considering adenoidectomy in adolescent age group, and should be considered only if causing any other upper respiratory tract infection exists.
When performing maxillary distraction in patients with cleft palate in the mixed dentition stage, and when velopharyngeal closure is found to occur by velar contact against the hypertrophied adenoid, patients should be counseled about risks of subsequent deterioration in their speech before surgery. It would be beneficial to provide information about the risk involved in maxillary forward distraction for patients with hypertrophied adenoids; some may feel that the benefit of maxillary forward distraction would outweigh the risk of subsequent velopharyngeal insufficiency.
| Conclusion|| |
Adenoid size was increased in the juvenile and adolescent cleft group as compared to the non-cleft group. Airway passage size was reduced in the juvenile and adolescent cleft group as compared to the non-cleft group. Nasopharyngeal area was larger in the non-cleft group as compared to the cleft group. Adenoidal: Nasopharyngeal ratio was higher in the cleft group as compared to the non-cleft group. Decreased posterior height of maxilla was seen in the cleft group as compared to the non cleft group. Length of maxilla was smaller and retropositioned in cleft as compared to non-cleft. Length of velum was smaller in cleft subjects as compared to non-cleft subjects and the need ratio was increased in cleft patients as compared to non-cleft patients. A significant correlation exists between the size of adenoids, airway passage, size and position of maxilla, velum length and need ratio. As age advances, adenoid size velum length decreases. Greater need ratio was suggestive of velopharyngeal incompetence in adolescent stage in cleft subjects.
| References|| |
|1.||Van Cauwenberge PB, Bellussi L, Maw AR, Paradise JL, Solow B. The adenoid as a key factor in upper airway infections. Int J Pediatr Otorhinolaryngol 1995;32:71-80. |
|2.||Linder-Aronson S. Adenoids: Their effect on mode of breathing and nasal airflow and their relationship to characteristics of the facial skeleton and the dentition. Acta Otolaryngol Suppl 1970;265:1-132. |
|3.||Handelman CS, Osborne G. Growth of the nasopharynx and adenoid development from one to eighteen years. Angle Orthod 1976;46:243-59. |
|4.||Ren Y, Isberg A, Henningsson G. Interactive influence of a pharyngeal flap and an adenoid on maxillofacial growth in cleft lip and palate patients. Cleft Palate Craniofacial J 1993;30:144-9. |
|5.||Warren DW, Hairfield WM, Dalston ET, Sidman JD, Pillsbury HC. Effects of cleft lip and palate on the nasal airway in children. Arch Otolaryngol Head Neck Surg 1988;114:987-92. |
|6.||Linder-Aronson S, Leighton BC. A longitudinal study of the development of the posterior nasopharyngealwall between 3 and 16 years of age. Eur J Orthod 1983;5:47-58. |
|7.||Subtelny JD. The significance of adenoid tissue in orthodontia. Angle Orthod 1956;24:59-69. |
|8.||Imamura N, Ono T, Hiyama S, Ishiwata Y, Kuroda T. Comparison of the sizes of adenoidal tissues and upper airways of subjects with and without cleft lip and palate. Am J Orthod Dentofacial Orthop 2002;122:189-94. |
|9.||Kemalogu Y.K, Gosku N, Inale, Akyildic N. Radiographic evaluation of children with nasopharyngeal obstruction due to the adenoid. Am J Orthod Dentofacial Orthop 1999;108:67-72. |
|10.||Chen ZQ, Qian YF, Wang GM, Shen G. Sagittal maxillary growth in patients with unoperated isolated cleft palate. Cleft Palate Craniofac J 2009;46:664-7. |
|11.||Ross RB. Treatment variables affecting facial growth in complete unilateral cleft lip and palate. Cleft Palate J 1987;24:5-77. |
|12.||Ross RB. Treatment variables affecting facial growth in complete unilateral cleft lip and palate. Part 3: Alveolus repair and bone grafting. Cleft Palate J 1987c;24:33-44. |
|13.||Horswell L. Craniofacial growth in UCLP, from 8 to 18 yrs. Cleft palate J 1997;24:114. |
|14.||Blanco B. Variation in arch and tooth sizes in upper jaw of cleft palate patients. Odontol Chil 1989;37:229-39. |
|15.||Gabriel O, Camargo da Silva, Filho OG, Ramos AL. Influence of Unilateral cleft lip and palate on dental arch morphology, Angle Orthod 1992;62:283-90. |
|16.||Friede H, Priede D, Moller M, Maulina I, Barkane B. Comparisons of facial growth in patients with unilateral cleft lip and palate treated by different regimens for two-stage palatal repair. Scand J Plast Reconstr Surg Hand Surg 1999;33:3-81. |
|17.||Rohrich RJ, Roswell AR, Johns DF, Drury MA, Grieg G, Watson DJ, et al. Timing of hard palate closure: A critical long-term analysis. Plast Reconstr Surg 1996;98:236-46. |
|18.||Wada T, Satoh K, Tachimura T, Tatsuta U. Comparison of nasopharyngeal growth between patients with clefts and noncleft controls. Cleft Palate Craniofac J 1997;34:405-9. |
|19.||Wu JT, Huang GF, Huang CS, Noordhoff MS. Nasopharyngoscopic evaluation and cephalometric analysis of velopharynx in normal and cleft palate patients. Ann Plast Surg 1996;36:117-22. |
|20.||Lu Y, Shi B, Zheng Q, Xiao W, Li S. Analysis of Velopharyngeal Morphology in Adults with Velopharyngeal Incompetence After Surgery of a Cleft Palate. Ann Plast Surg 2006;57:50-4. |
[Table 1], [Table 2], [Table 3], [Table 4]