Assessment of pharyngeal airway in unilateral adult cleft lip and palate patients using Three-dimensional methods

Abstract

Aim: The objective of this study was to establish the characteristics of the nasopharyngeal airway in adult cleft lip/palate subjects (CLP), and to compare them with normal adult subjects using three-dimensionally cone beam computed tomography images (3D CBCT). Subjects and Methods : The sample comprised control subjects (n=15) and adult unilateral cleft lip/palate subjects (n=15). Eighty-seven scans derived from 3D CBCT of the two groups were analyzed. A set of airway, and group of volumetric parameters were measured. CBCT scans were coded and measurements Landmarks were identified and measured using Dolphin 3D Imaging software server (version 11.7; Patterson Dental Supply, Chatsworth,Calf.). Results: All the volumetric measurements of the cleft group showed significant lower total volume for Nasal Cavity, Nasopharynx ,Oropharynx ,Hypopharynx and total airway volume than the control group. Conclusion: Adult unilateral CLP subjects had smaller nasopharyngeal parameters relative to normal adult subjects. (3144) Ayman R. Khalifa, et al. E.D.J. Vol. 65, No. 4 correction of cleft defects (e.g. palatoplasty) (4). Therefore, a percentage of children with CLP are at high risk for sleep-disorders (5). Sleep-disordered breathing is a spectrum of conditions that frequently impact the person ability to get enough quality of sleep. In children, CLP increases the risk for the sleep-disordered breathing due to the dysfunction of muscles controlling the soft palate in conjunction with structural abnormalities of the maxilla and the mandible (6). Furthermore, CLP patients are at increased risk for hypertension, cardiovascular and cerebrovascular diseases, and excessive daytime sleepiness (7). In CLP patients, the associated craniofacial features include midface deficiency, retrognathic mandible resulting in the reduction of the pharyngeal airway volume (6). All previously mentioned research indicates that The condition of the upper airway is an important field for orthodontists. Therefore, morphometric evaluation of the pharyngeal airway in patients with CLP is important(8). Two-dimensional (2D) cephalometrics are the most commonly used by orthodontists to measure size and relative proportions of pharyngeal airway, but 2D measurements are inaccurate and prone to errors especially in the 2D interpretation of 3-dimensional (3D) structures (9). Technological advances in imaging have led to accurate three-dimensional (3D), high resolution digital records of hard and soft tissues. Several imaging technologies, such as spiral or helical computed tomography (CT) and dental cone-beam computed tomography (CBCT), are widely acting as diagnostic and research instruments in orthodontics and craniofacial surgeries (10,11). There is an increasing agreement on the reliability of CBCT 3D assessment of the pharyngeal airway volume (12,13,14,15). Using CBCT technologies, investigators studying airway patency, function and disorders; provided promising preliminary data including dimensions of airway anatomy in normal adults (10) . Three-dimensional CBCT images offer an accurate representation of the airway. Using CBCT, several studies demonstrated the differences in the nasopharyngeal airway volume with CLP growing subjects compared to normal subjects (16,17,18,19,20) . Therefore, the main purpose of this study was to establish the characteristics of the pharyngeal airway in adult CLP subjects, and to compare them with well matching control groups of normal adult subjects using CBCT, in addition to investigating the gender differences between groups. MATERIAL AND METHODS This retrospective study was developed on subjects recruited from the department of maxillofacial and plastic surgery, School of Dentistry, 6 October University, Giza, Egypt. All patients and patients caregivers had signed an informed consent for allowing the use of their data for scientific purposes. We obtained the ethical committee approval was obtained to use deidentified CBCT scans from patients with/without CLP who had undergone preoperative CBCT imaging at the department of oral radiology. The exclusion criteria were: history of orthognathic surgical repair, history of airway abnormalities or pathosis. A further exclusion criterion for the control group included any type of syndrome or craniofacial anomalies. All individuals with CLP had no pre-operative orthodontic intervention. The sample of the study included 30 subjects and were classified into : 1Unilateral cleft adult (UCLP) with cleft in the left side : 15 subjects patients (8 males 7 females) were included. The age range for adult cleft subjects was between18-27 years, ASSESSMENT OF PHARYNGEAL AIRWAY IN UNILATERAL ADULT CLEFT LIP (3145) 2The normal Non CLP sample included: Non -Growing : 15 subjects (8 males 7 females) with (age range between 18-27 years). The CBCT images were obtained using ILUMA Ultra Cone Beam CT Scanner system, KODAK 9000 3D System, IMTEC Imaging Corporation, Ardmore, Oklahoma). Each scan took 40 seconds and had Grayscale 16 bit (31744-45811 shades of gray). It gives 1:1 scale images, and CT slices thickness 0.28 mm. The CBCT images were uploaded into Dolphin 3D imaging software server (version 11.7; Patterson Dental Supply, Chatsworth, Calif) then measured and viewed on the same computer and monitor. Table (I) and Figure (1) . All CBCT images were coded, and information on age and sex was recorded. The prevertebral soft-tissue thickness was measured as the distance parallel to the Frankfort horizontal plane from 3 points on the CV 2, CV 4 to the posterior wall of the airway. Bony structure and soft tissue transposed on each other in midsagittal plane with the 3D Dolphin imaging system. Statistical Analysis: Kolmogorov–Smirnov test showed a nonparametric data distribution for tested parameters. Kruskal Wallis test used to compare between tested groups followed by Mann-Whitney U test for pairwise comparison. Mann-Whitney test was used to compare between Male and female groups. (α=0.05). Fig. (1) Airway segmentation and volume and minimal area measurements. Screenshots from Dolphin software, show the segmentation and volume measurement of the airway space as shown in table (1). From top left to right, nasal cavity, nasopharynx, and oropharynx are segmented and measured. (3146) Ayman R. Khalifa, et al. E.D.J. Vol. 65, No. 4