This study aims to develop and validate a quantitative prediction model using three-dimensional computed tomography (3D-CT) imaging for identifying infants with Pierre Robin sequence (PRS) at risk of difficult laryngoscopy. A dual-parameter model incorporating the oropharyngeal sagittal area (S2) and the distance between the tongue base and the posterior pharyngeal wall (D4) will be established. Internal validation will be performed using data from PRS infants treated between 2023 and 2024, and temporal external validation will be conducted using an independent cohort from 2025.

This study seeks to provide an accurate, non-invasive tool for preoperative airway risk assessment in PRS infants, thereby improving anesthetic safety and clinical decision-making.

This retrospective cohort study includes infants diagnosed with Pierre Robin sequence (PRS) who underwent mandibular distraction osteogenesis at the Children's Hospital of Nanjing Medical University between January 2023 and September 2025. Preoperative three-dimensional computed tomography (3D-CT) scans will be used to measure quantitative airway parameters, including the oropharyngeal sagittal area (S2) and the distance from the tongue base to the posterior pharyngeal wall (D4).

According to Cormack-Lehane grades obtained during laryngoscopy, infants will be classified into easy (grades I-II) and difficult (grades III-IV) exposure groups. Logistic regression will be used to identify independent predictors of difficult laryngoscopy, and a dual-parameter model combining S2 and D4 will be developed. The model's discrimination, calibration, and clinical usefulness will be assessed by receiver operating characteristic (ROC) curve analysis, calibration plots, and decision curve analysis (DCA).

Internal validation will be performed using bootstrap resampling (1000 iterations), and temporal external validation will be conducted using an independent cohort from 2025. The goal of this study is to construct a simple, objective, and reproducible model that can improve preoperative airway risk evaluation and support anesthetic management in PRS infants.

Inclusion Criteria:Infants diagnosed with Pierre Robin sequence (PRS) based on mandibular hypoplasia, glossoptosis, and upper airway obstruction.

Undergoing mandibular distraction osteogenesis under general anesthesia.

Complete preoperative 3D-CT imaging data available.

Complete intraoperative laryngoscopic grading recorded (Cormack-Lehane classification).

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Exclusion Criteria:

• Presence of other craniofacial syndromes (e.g., Treacher Collins syndrome, Goldenhar syndrome).

Incomplete or poor-quality 3D-CT images.

Missing laryngoscopic grading or intraoperative data.

History of airway surgery before CT imaging.

This study included infants diagnosed with Pierre Robin sequence who underwent mandibular distraction osteogenesis under general anesthesia at Nanjing Children's Hospital between January 2023 and December 2025. All participants had complete preoperative 3D-CT imaging and intraoperative laryngoscopic grading records.

Individual participant data will not be shared because this is a retrospective study involving patient privacy-sensitive information.