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BACKGROUND:
Volumetric and soft tissue changes to the midface after Le Fort 1 advancement for the treatment of cleft-related maxillary hypoplasia remain understudied. Differential soft tissue expansion may occur following maxillary advancement due to cleft-related facial scarring and segmentation of the maxilla. The aim of this study is to analyze and compare facial volumetric and soft tissue changes between single and two-piece Le Fort I osteotomies.
METHODS:
A 24-month retrospective cohort study correlating cephalometric and volumetric changes in cleft palate patients with maxillary hypoplasia treated with Le Fort 1 osteotomy (single- or two-piece) was performed. Cephalometric parameters (overjet, overbite, soft tissue advancement, and volumetric changes of the midface using 3D stereo photogrammetric imaging (Vectra XT Imaging System, Canfield Scientific, Inc., Fairfield, NJ) were analyzed. Advancement distances at subnasale (SN), labium superius (LS) and stomion (STO) and volume change of the midface (infraorbitale to oral commissure) were evaluated. Statistical analysis was performed using SPSS 20.0.
RESULTS:
11 patients (7 male, 4 female) who met inclusion criteria underwent 11 total Lefort I advancements (Group 1, single piece n=7; Group 2, two-piece advancement, n=4). All patients were diagnosed with non-syndromic cleft-related maxillary hypoplasia and class III malocclusion. Average age at orthognathic surgery was 17.4 years (15.3 - 19.3) in Group 1, and 19.2 years (17.1 - 22.5) in Group 2 (p=0.051). Average operative time was 213.8 minutes (117-317) in Group 1, and 229.3 minutes (119-323) in Group 2 (p=0.73). Average 3D photographic follow-up was 4.24 months in Group 1 and 6.72 months in Group 2. The average cephalometric advancement at maxilla central incisor (MCI) edge was 7.0 (5.1 - 8.5) mm in Group 1 and 5.4 (3.3 - 7.4) mm in Group 2 (p=0.058). The average soft tissue point advancement was SN 5.7 mm, LS 7.1 mm and STO 6.1 mm in Group 1 and SN 4.2 mm, LS 3.4 mm and STO 3.7 mm in Group 2 (p=0.34, 0.01, 0.02 respectively). The average volumetric change in Group 1 was 14.1 ml (2ml/mm advancement) and 9.0 ml (1.67 ml/ mm advancement) in Group 2 (p=0.14). No wound infections, bleeding requiring reoperation, recurrent malocclusion, or mortality occurred. There was no significant difference in pre-operative versus post-operative weight for either group (p=0.67, 0.60).
CONCLUSIONS:
Midface advancement was consistently and significantly expanded at labium superius (LS) and stomion (STO) using single-piece compared to two-piece Le Fort 1 advancements. Facial advancement (soft tissue points, STO) was less than calculated cephalometric advancement (bone points, MCI) by 13 percent in single and 32 percent in two-piece advancements. Midface volumetric changes were not significantly different between groups but greater variability with two-piece Le Fort 1 advancement was noted. Single-piece Le Fort 1 advancement for the treatment of maxillary hypoplasia in cleft patients yields more predictable midface soft tissue advancement and less variable volumetric expansion.