Early Prediction of the Need for Orthognathic Surgery in Patients with Repaired Unilateral Cleft Lip and Palate using Machine Learning and Longitudinal Lateral Cephalometric Analysis Data

Abstract

Background: Some patients with unilateral cleft lip and palate (UCLP) need orthognathic surgery or distraction osteogenesis (DO) to obtain a more balanced intermaxillary relationship and improved esthetic outcome. This study was conducted to determine the cephalometric parameters that can predict the future need for orthognathic surgery or DO in Korean patients with repaired UCLP by using machine learning and longitudinal lateral cephalometric analysis. Method: We included 56 Korean patients with UCLP (31 males and 25 females), who were treated by a single surgeon and a single orthodontist with the same treatment protocol. Lateral cephalograms were obtained before the commencement of orthodontic/orthopedic treatment (T0; mean age, 6.3 years) and at at least 15 years of age (T1; mean age, 16.7 years), and 38 cephalometric variables were measured. At the T1 stage, 3 cephalometric criteria were used to classify the participants into the surgery and non-surgery groups (ANB ≤ −3°; Wits appraisal ≤ −5 mm; Harvold unit difference ≥34 mm for the surgical group). They were divided into the surgical group (n=10, 17.9%) and the non-surgical group (n=46, 82.1%). The one-way analysis of variance, Fishers exact test, and independent t-test were used for statistical analyses. The Boruta method and XGBoost algorithm were used to determine the cephalometric variables at the T0 stage for the development of a prediction model. Results: At the T0 stage, only 2 variables (ANB and Facial convexity angle, all P<0.05) exhibited a significant intergroup difference. At the T1 stage, 18 cephalometric variables showed a significant intergroup difference (A-N perp, SNB, ODI, articular angle, mandibular body length, IMPA, bisecting Occ plane to FH plane angle, occlusal plane to SN plane angle, and upper gonial angle, all P<0.05; Pog-N Perp, Co-Gn, and AB-MP, all P<0.01; and ANB, Wits appraisal, APDI, Harvold unit difference, facial convexity angle, and AB to occlusal plane angle, all P<0.001). For the quantification of change from T0 to T1, 14 variables exhibited a significant intergroup difference (ΔSNB, ΔPog-N Perp, ΔCo-Gn, ΔHarvold unit difference, ΔSN-MP, ΔWits appraisal, ΔBjork Sum, ΔMandibular body length, and ΔBody to anterior cranial base ratio, all P<0.05; ΔANB, ΔAB-MP, ΔFacial convexity, and ΔAB to occlusal plane angle, all P<0.01; ΔAPDI, P<0.001). At the T0 stage, the ANB, PP-FH, CF, and facial convexity angle were selected as predictive parameters, and had a 10-fold cross-validation accuracy of 87.4% with an F1-score of 0.714. Conclusion: The 4 cephalometric variables identified in this study might be considered effective predictors, at approximately age 6 years, of the future need for orthognathic surgery to correct sagittal skeletal discrepancies in Korean patients with UCLP.

서론: 편측성 구순구개열 환아는 안면 뼈 성장이 끝난 후 부정교합 또는 악안면 외형적인 문제로 악교정 수술 혹은 신연골형성 수술 (DO) 필요한 경우가 흔히 있다 (약 12%~40%로 보고되고 있다). 본 연구의 목적은 machine learning을 이용하여 편측성 구순구개열 환아의 lateral cephalometric 계측치로 악안면 뼈 성장 예후 또는 악교정술 혹은 DO 수술의 필요성의 예측이 가능한지 조사하는 것이다. 방법: 동일한 성형외과의사 그리고 교정과의사의 같은 진료방침으로 치료를 받은 총 56명의 편측성 구순구개열 환아들을 대상으로 연구 하였다. 환아들의 교정/정형 치료받기 전 시기 T0 (평균연령 6.3세) 및 15세 이후 시기 T1 (평균연령 16.7세)의 lateral cephalogram을 수집 및 digitize하였다. 38개의 cephalometric 계측치들을 분석하였다. T1시기의 3개의 계측치 (ANB ≤ -3°; Wits appraisal ≤ -5 mm; Harvold unit difference ≥ 34 mm; 수술군)를 기준으로 환아들을 수술군 (n=10)과 비수술군 (n=46)으로 나누었다. Independent t test 통계분석을 실행 하였으며, Boruta 방법과 XGBoost algorithm을 사용하여 T0에서 악안면 뼈 성장을 예측 할 수 있는 계측치를 탐색하였다. 결과: T0 시기의 2개의 cephalometric 계측치 [ANB과 Facial convexity angle (FCA), 모두 P < 0.05] 결과에서 그룹간 유의한 통계 차이를 보였다. T1 시기의 18개의 계측치와 ΔT1-T0 (T0~T1 변화 값)의 14개의 계측치에서 유의한 차이가 관찰 되었다 (모두 P < 0.05). T0 시기 안면 뼈 성장 예후 예측이 가능한 계측치는 ANB, PP-FH, Combination factor, 그리고 Facial convexity angle로 확인되었다. 10-fold Cross-Validation 정확도는 87.4%이며 F1-score는 0.714로 확인되었다 (Sensitivity, 97.83%; Specificity, 90.00%). 결론: 편측성 구순구개열 환자 6세 시기에, 높은 정확도로 악안면 뼈 성장 예후 또는 뼈 성장 종료 후의 악교정 수술 혹은 신연골형성 수술 실행 여부 판단이 가능하다.