Cephalometric parameters and airway changes in relation to orthognathic cleft surgery- A pilot study / Asiyah @ Khairul Bariyyah Ayob

Asiyah @ Khairul Bariyyah , Ayob (2024) Cephalometric parameters and airway changes in relation to orthognathic cleft surgery- A pilot study / Asiyah @ Khairul Bariyyah Ayob. Masters thesis, Universiti Malaya.

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Abstract

Cephalometric parameters can be a good predictive criterion for orthognathic surgery needs in cleft patients. However, caution must be exercised when implementing maxillo-mandibular movements due to potential modifications in the posterior airway space. OBJECTIVE: This pilot study aims to identify quantitative skeletal, dental, and soft tissue cephalometric parameters associated with the orthognathic surgical approach for cleft patients and relate post-surgery airway changes to the surgical approaches undertaken. MATERIAL AND METHOD: The study was a retrospective cross-sectional by design which analysed pre- and post-surgical lateral cephalometrics of non-syndromic cleft lip and palate patients who underwent orthognathic surgery at the University of Malaya Medical Centre between the year 2013 and 2023. Three bilateral cleft lip and palate patients (BCLP) and ten unilateral cleft lip and palate (UCLP) aged 12- 35 years old (mean 21.38) were included for analysis, with no gender or race stratification given the small number recruited plus no comparison made to the normal range. The study analysed mean values for ten cephalometric parameters for maxillary advancement surgery, bimaxillary surgery, and distraction osteogenesis. Also, it focused on different levels of posterior airway change for the respective surgery. Kruskal-Wallis's test was utilized to determine the association between posterior airway changes and the type of orthognathic surgical approaches. RESULT: Thirteen samples were analysed out of the identified seventy cleft lip and palate (CLP) patients. The data was presented using the mean and standard deviation, as it was normally distributed. The calibration of both inter- and intra-examiners was conducted to ensure measurement accuracy and consistency, with an ICC value of 0.9, respectively. For maxillary advancement surgery mean values observed were SNA 76.70°; SNB 78.50°; ANB -1.85°; MMPA 36.70°; LFH 58.15%; the upper incisor inclination (U1-MxPl) 111.30°; lower incisor inclination (L1- MnPl) 87.45°, upper lip to E line (Ulip-E) -9.7mm; lower lip to E line (Llip-E) 1.30mm, nasolabial angle (NLA) 89.80°. Post-surgery, the mean nasopharyngeal airway change was 2.6mm. Oropharyngeal, hypopharyngeal and deep pharyngeal airway changes were 1.9mm, 0.15mm and 3.05mm, respectively. For bimaxillary surgery (Le Fort I maxillary advancement with bilateral split sagittal osteotomy mandibular setback), mean values observed for the parameters were: SNA 76.23°; SNB 82.17°; ANB -5.97°; MMPA 27.34°; LFH 56.17%; U1-MxPl 123.11°; L1-Mn-Pl 88.31°, Ulip-E -5.41mm; Llip-E 4.84mm, NLA 64.37°. The mean airway changes with regard to this surgery at the nasopharynx, oropharynx, hypopharynx and deep pharynx were 3.09mm, -3.79mm, -2.29mm and 0.07mm, respectively. For distraction osteogenesis, the mean values of parameters were SNA 73.43°, SNB 83.85°, ANB -10.43°, MMPA 26.63°, LFH 55.65%, U1-MxPl 115.38°, L1- MnPl 90.10°, Ulip-E -8.05mm, Llip-E 4.60mm and the NLA 61.75°. The posterior airway changes by the surgical mean were 1.40mm, 1.18mm,2.53mm, and 4.33mm, respectively, to the nasopharynx, oropharynx, hypopharynx and deep pharynx. CONCLUSION: The pilot study reveals certain cephalometric parameters with substantial variation in cleft patients, potentially indicating the need for specific orthognathic surgery. It was found that Le Fort I maxillary advancement and distraction osteogenesis increase posterior airway dimensions, while bimaxillary surgery reduces them, however no significant association was found.

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