Montreal Children's Hospital formula for nasoalveolar molding cleft therapy.

BACKGROUND: For cleft teams that use nasoalveolar molding for presurgical treatment of cleft lips, the determination of desired cleft-nasal height correction is a subjective assessment. The latter, however, is complicated by a noncleft nasal height that itself is depressed by the shifted nasal pyramid native to the deformity. The authors introduce a simple formula based on the Pythagorean theorem to estimate the corrected height of the nose as an objective guide for the endpoint of nasoalveolar molding therapy.

METHODS: Nasal impressions of 20 consecutive patients with unilateral cleft lips who underwent nasoalveolar molding therapy were analyzed. Using identified landmarks on pre-nasoalveolar molding impressions, the Montreal Children's Hospital formula was used to estimate the corrected height of the noncleft nostril (ideal corrected nasal height) as measured on the impressions after nasoalveolar molding therapy had verticalized the nasal pyramid. Statistical analysis was performed using the Pearson correlation test to determine the predictive value of the formula.

RESULTS: Twenty patients were included in the study. Analysis demonstrated a statistically significant positive correlation (high degree) between predicted nasal heights (ideal corrected nasal height) and those measured following completion of nasoalveolar molding therapy (r = 0.760, p < 0.01).

CONCLUSIONS: The Montreal Children's Hospital formula may serve as a useful tool to predict the corrected nasal height (ideal corrected nasal height) as a benchmark for cleft side nasal correction with nasoalveolar molding. The authors hope it will provide cleft teams, especially those beginning to use nasoalveolar molding, with an objective measure to guide nasoalveolar molding treatment.