Piriform Rim Asymmetry in Unilateral Cleft Lip and Palate Patients Before Orthognathic Surgery

Area of Science:

• Craniofacial surgery
• Orthodontics
• Plastic surgery

Background:

• Complete unilateral cleft lip and palate (UCLP) causes nasal floor defects and asymmetry.
• Piriform rim symmetry is traditionally assessed by comparing cleft and non-cleft sides.
• No prior studies compared perinasal asymmetry magnitude in UCLP patients to controls.

Purpose of the Study:

• To determine if piriform rim asymmetry in UCLP patients, after alveolar bone grafting (ABG), is similar to that in non-UCLP individuals.
• To quantify remaining piriform rim asymmetry in UCLP patients post-ABG.

Main Methods:

• Retrospective cohort study utilizing cone beam computed tomography (CBCT) scans.
• Evaluated piriform rim symmetry in UCLP patients (n=30) and controls (n=30) undergoing orthognathic surgery.
• Measured piriform rim asymmetry using distances to reference lines on pre-orthognathic CBCT.

Main Results:

• UCLP patients exhibited significant piriform rim asymmetry (inferior: 3.9mm, lateral: 3.6mm) compared to controls (0.1mm for both).
• Alar base soft tissue thickness discrepancy was significantly greater in UCLP patients (3.1mm) versus controls (0mm).
• Turbinate area differences showed greater variability in the UCLP group (314mm²) than controls (35mm²).

Conclusions:

• Alveolar bone grafting using symphyseal bone and BMP did not achieve symmetry comparable to non-cleft patients.
• Persistent asymmetry in UCLP patients is associated with increased alar base tissue thickness and turbinate size variability.
• Further research may be needed to optimize surgical techniques for improved piriform rim symmetry.