Velopharyngeal anatomy and maxillary advancement.

Area of Science:

• Orthognathic Surgery
• Craniofacial Anatomy
• Velopharyngeal Physiology

Background:

• Maxillary retrusion presents significant aesthetic and functional challenges.
• Surgical correction, such as total maxillary advancement, impacts surrounding anatomical structures.
• Understanding velopharyngeal mechanism changes is crucial for predicting post-operative speech outcomes.

Purpose of the Study:

• To radiographically evaluate changes in the static velopharyngeal mechanism after total maxillary advancement.
• To compare these changes between non-cleft and cleft-lip patient groups.
• To establish a predictive method for velopharyngeal function based on anatomical measurements.

Main Methods:

• Retrospective analysis of radiographic records from 21 patients (13 non-cleft, 8 cleft-lip) undergoing total maxillary advancement.
• Measurement of soft palate angle to hard palate and soft palate length.
• Calculation of the pharyngeal need ratio (pharyngeal depth/soft palate length).

Main Results:

• Total maxillary advancement induced anatomical changes in the velopharyngeal mechanism in both patient groups.
• The angle of the soft palate to hard palate increased (2°/mm in non-cleft, 1°/mm in cleft).
• Soft palate length increased (.5mm/mm in non-cleft, .4mm/mm in cleft).
• A pharyngeal need ratio of 0.68–0.84 was observed; a ratio >1 suggests probable velopharyngeal incompetence.

Conclusions:

• Total maxillary advancement significantly alters velopharyngeal anatomy.
• While changes are similar, the magnitude differs between non-cleft and cleft-lip patients.
• The pharyngeal need ratio shows potential for predicting velopharyngeal competence post-surgery.