Oronasal fistulas in cleft palate patients and their influence on speech.

The size, site, and influence on speech of oronasal fistulas were studied in 12 patients with unilateral and 32 with bilateral cleft lip and palate. There were more and larger fistulas in the bilateral group. The series was divided into: those with fistulas that affected speech (group A, n = 18) and those with fistulas that did not affect their speech (group B, n = 26). Group A had significantly larger fistulas than group B, but there were no differences in the sites of the fistulas, either between the bilateral and unilateral groups or between groups A and B. Most fistulas were located in the region of the incisive foramen or in the hard palate. Judgements by listeners and analyses by the NORAM instrument were made of the speech of 12 of the patients in group A before and after temporary covering of the fistulas. Significant differences in hypernasality, according to both listener's judgments and instrumental analyses were found. This finding is further evidence that an oronasal fistula can influence and contribute to velopharyngeal dysfunction.