LeFort I Horizontal Osteotomy: Defining the Feasibility of the "High Osteotomy".

Objective: To define "high osteotomy" and determine the feasibility of performing this procedure.

Design: Single institution, retrospective review.

Setting: Academic tertiary referral hospital.

Patients, Participants: 34 skeletally mature, nonsyndromic patients with unilateral CLP who underwent Le Fort I osteotomy between 2013 and 2020. Patients with cone-beam computed tomography (CBCT) scans completed both pre- (T1) and post-operatively (T2) were included. Patients with bilateral clefts and rhinoplasty prior to post-operative imaging were excluded.

Interventions: Single jaw one-piece Le Fort I advancement surgery.

Main Outcome Measures: Measurements of the superior ala and inferior turbinates were taken from the post-operative CBCT.

Results: The sample included 26 males and 8 females, 12 right- and 22 left-sided clefts. The inferior turbinates are above the superior alar crease at a rate of 73.53% and 76.48% on the cleft and non-cleft sides, respectively. One (2.9%) osteotomy cut was above the level of the cleft superior alar crease, and no cuts were above the level of the non-cleft superior ala. On average, the superior ala was 2.63 mm below the inferior turbinates. The average vertical distances from the superior alar crease and the inferior turbinates to the base of the non-cleft side pyriform aperture were 12.17 mm (95% CI 4.00-20.34) and 14.80 mm (95% CI 4.61-24.98), respectively. To complete a "high osteotomy," with 95% confidence, the cut should be 20.36 mm from the base of the pyriform aperture.

Conclusions: A "high" osteotomy is not consistently possible due to the relationship between the superior alar crease and the inferior turbinate.