sentence: The frequency of secondary velopharyngeal surgery in isolated cleft palate patients ( Veau I and II types ) was 13.6 % ( 94/1425 ) , compared to 15.8 % ( 247/1562 ) in unilateral ( Veau III type ) clefts and 13.5 % ( 69/513 ) in bilateral ( Veau IV type ) clefts.Cleft type was a significant factor in the frequency of pharyngoplasty surgery .