BACKGROUND: The current literature on orthognathic growth outcomes after velopharyngeal insufficiency (VPI) surgery is limited by cohort size or short follow-up duration after surgery. This study evaluates the relationship between sphincter pharyngoplasty and long-term maxillomandibular growth. METHODS: All patients with cleft lip and palate (CLP) or isolated cleft palate (iCP) ≥15 years of age who underwent sphincter pharyngoplasty from 1992 to 2023 were retrospectively reviewed. An age- and diagnosis-matched control group with CLP/iCP was also identified. Postoperative outcomes include clinical diagnosis of maxillary and mandibular hypoplasia, indication for Lefort surgery, as well as sella-nasion-A point (SNA) and sella-nasion-B point (SNB) angles. RESULTS: 200 CLP/iCP patients with a mean age of 20.0±3.2 years were included (n=114 with pharyngoplasty, n=86 control). Within the surgery cohort, pharyngoplasty occurred at a mean age of 12.0±4.5 years with a follow-up duration 9.2 (IQR 3.5-12.2) years after surgery. Maxillary hypoplasia was diagnosed twice as frequently in pharyngoplasty patients compared to controls (60.5% vs. 33.7%, p<
0.001), corresponding to a higher incidence of Lefort I surgery (45.6% vs. 15.1%, p<
0.001) and smaller SNA angles (75.4±4.5° vs. 78.2±5.4°, p=0.03). There were no differences in mandibular hypoplasia or SNB angles. Multivariable analysis indicated that pharyngoplasty was independently associated with a three-fold increase in later diagnosis of maxillary hypoplasia (OR=3.8, 95%CI 1.9-7.5, p<
0.001). CONCLUSIONS: Patients with a history of pharyngoplasty were 3.8 times more likely to be subsequently diagnosed with maxillary hypoplasia, highlighting the need for longitudinal follow-up of patients after VPI surgery as there may be long-term orthognathic consequences.