Orthognathic surgery utilizing a Le Fort I osteotomy is performed regularly by oral surgeons to correct midface and dental occlusal abnormalities, yet little has been written discussing the impact these operations may have on sinonasal function. The objective of this study was to assess the incidence of objective sinonasal inflammation and subjective sinonasal symptoms following the use of Le Fort I osteotomies for maxillary advancement surgery.Thirty-eight subjects who previously underwent Le Fort I osteotomies for purposes of elective orthognathic surgery were enrolled retrospectively to assess for evidence of rhinosinusitis (RS). Post-operative and, when available, preoperative maxillofacial computed tomography (CT) scans were obtained and evaluated using Lund Mackay scoring (LMS). The Chronic Sinusitis Survey - Duration Based (CSS-D) was completed to compare subjective symptoms before and after surgery.Evaluation of the CT scans demonstrated radiographic evidence of RS and subjective worsening of symptoms in 87% and 89% respectively. The mean CSS-D pre- and post-operative scores were 7.6 and 14.8 respectively (P < 0.0001). The mean calculated LMS was 3.39 (2.38-4.40, 95% C.I.). Further sub-analyses demonstrate an increase in both radiographic LMS and subjective CSS-D for patients who had persistent inferior meatal antrostomies after Le Fort I osteotomy.Le Fort I osteotomies performed during orthognathic surgery result in a higher prevalence of post-operative RS than what has been previously described. A better understanding of sinonasal mucocilliary function and the aberrancy that may be caused following such operations deserves further evaluation in order to identify and optimize postsurgical outcomes.