A Study of Border Line Cases of Velopharyngeal Incompetence Using Cephalometry and Nasofibroscopy

The velopharyngeal mechanism is constituted by the muscles of the soft palate, posterior and lateral pharyngeal walls (1), separating the oropharynx from the nasopharynx. Such structures, particularly the soft palate, play a key role in the velopharyngeal closure physiology (2). Velopharyngeal closure patterns may be classified as follows: coronal, where there is predominant soft palate movement toward the posterior pharyngeal wall; sagittal, where there is predominant movement of the lateral pharyngeal walls toward the pharynx midline; circular, where balanced movements of lateral pharyngeal walls and soft palate are observed; circular with Passavant's ridge, where the circular closure is associated with the development of a mucosal fold named Passavant's ridge on the posterior pharyngeal wall(3). The velopharyngeal closure allows the separation between the nasal and oral cavities during activities such as oral sounds emission, blowing, whistling, swallowing, sucking and vomiting reflex, respecting the level of closure demanded by each activity (4,5).

In cases where the structures of the velopharyngeal mechanism do not work properly, the presence of a space called velopharyngeal aperture is observed between them, characterizing a velopharyngeal dysfunction. One of the reasons for the occurrence of such an aperture is the shortage of soft palate tissue. This dysfunction is called velopharyngeal insufficiency and may be corrected either surgically or by prosthetic management followed by speech therapy. In cases where such dysfunction occurs because of a failure in the velopharyngeal structures movement, physiological or neuromotor deficiency, it is called velopharyngeal incompetence that may be eliminated by means of speech therapy (2,6). On the other hand, if such condition is a result of the presence of compensatory articulations or other speech learning errors, it does not reflect physical or neuromuscular alterations, constituting indication for speech therapy(7). Individuals with velopharyngeal dysfunction present hypernasality, nasal air emission, poor intraoral pressure, and may present associated nasal/facial movements and compensatory articulations during the emission of oral consonants (8,9).

Assessment of the velopharyngeal function can be done by the following procedures:

1. Flexible fiberoptic nasopharyngoscopy (FFN) allows direct transnasal observation of the anatomy and dynamic activity of the velopharyngeal sphincter. Such observations can be recorded for permanent documentation by coupling FFN to a video camera with simultaneous audio recording. Numerous published reports discuss the advantages of FFN as a clinical method for evaluating velopharyngeal function during speech (10).

   Flexible fiberoptic nasopharyngoscopy (FFN) is a valuable tool for direct visualization because it allows observation of the velopharyngeal valve during dynamic activity for a prolonged period with (1) Minimal interference of the structures involved and (2) No radiation exposure. Whereas most clinicians acknowledge the theoretic advantages of FFN and accept it as a valid technique for assessing velopharyngeal function, there are few published studies that have addressed the validity and reliability of endoscopic procedures (10). Endoscopic evaluation has high face validity, and several reports have indicated that FFN has good construct validity when compared with radiologic assessments (11).

2. Cephalometric analysis, is the clinical application of cephalometry. It is analysis of the dental and skeletal relationships of a human skull and is frequently used by dentists, orthodontists, and oral and maxillofacial surgeons as a treatment planning tool.

Cephalometric analysis can also be applied for assessing the velopharyngeal structure and function. More specifically, velopharyngeal function in terms of its shape and mobility was analyzed quantitatively on the basis of cephalometric principle (12,13).

Border line cases of velopharyngeal incompetence of insufficiency are known to be problematic and usually causes confusion for phoniatricians especially in patients who will undergo adenotonsillectomy. For this purpose, objective assessment is necessary to support or reject the clinical findings of VPI cases.