Objective: To test the hypothesis that maxillary growth and lower lip form in patients with van der Woude syndrome (VDW) is different from patients with non-syndromic cleft lip and palate.
Design and setting: Retrospective, case-control study at a tertiary cleft center, Chang Gung Memorial Hospital, Taipei, Taiwan.
Patients and participants: Records of 53 patients with VDW, who presented for treatment during the years 1968 through 1998 were obtained. Twenty-three of 53 patients had received at least one lateral cephalogram during the course of their treatment. Of these 23, in 17 it was possible to find non-syndromic case controls with identical cleft type, sex, and method of cleft palate repair, with year of birth matching within 1 year of the corresponding VDW patient. For these 17 pairs of VDW and non-syndromic cleft controls, cephalogram acquisition dates were checked to see how well the corresponding pairs matched. A total of 43 pairs of cephalograms were deemed to be acceptably matched because the ages at acquisition differed by less than 15% of the VDW patient's age.
Main outcome measures: Thirteen measurements were derived from the 11 standard lateral cephalometric landmarks recorded on each cephalogram. The data were classified into five groups according to age at time of cephalogram, and sets of paired non-syndromic cleft and VDW measurements were tested for differences using a Wilcoxon signed rank sum test in two ways, first including all cleft types and then including only those patients with complete bilateral cleft lip and palate. A longitudinal growth analysis considering the movement of the skeletal A and B points was performed on the patients with complete bilateral cleft lip and palate.
Results: For the osseous measurements, anteroposterior maxillary length as described by the anterior nasal spine (ANS)-posterior maxillary point distance was statistically significantly shorter in the VDW patients of age 13 years and older, by 5.3 mm. Maxillary height, as described by the nasion-ANS distance was shorter in the VDW patients, closely approaching statistical significance in the age range 7 through 11 years. The lip soft tissue measurements showed significantly greater protrusion over several age ranges in the VDW patients. The longitudinal growth analysis showed a significantly more inferior vertical position of the B point in the controls.
Conclusions: This study demonstrates a few statistically significant differences in maxillary growth and lip conformation between VDW and matching controls. Small sample sizes for each age group hamper the ability to fully interpret or generalize the pattern of these differences.