Novel radiological indicators may accurately predict difficult laryngoscopy in cervical spondylosis patients: Study

Recent study introduced novel radiological indicators from lateral cervical X-rays in the extended head position to improve the accuracy of predicting difficult laryngoscopy, which is crucial for preoperative assessment of patients with cervical spondylosis.

The study included 402 patients scheduled for elective cervical spine surgery. Patients were categorized into "easy laryngoscopy" and "difficult laryngoscopy" groups based on the Cormack-Lehane grading system. Demographic data, conventional bedside indicators, and four radiological indicators were analyzed. The radiological indicators were: 1) Mandibular Length (ML): Length between mentum and mandibular angle 2) Laryngeal Height (LH): Distance from anterior border of thyroid cartilage to mandible 3) Larynx-Mandibular Angle Test (LMAT): Angle formed by lines connecting mentum to mandibular angle, and mandibular angle to anterior border of thyroid cartilage 4) Larynx-Mandibular Height Test (LMHT): Vector from mandibular angle to intersection point of a perpendicular line from thyroid prominence to the line connecting mentum and mandibular angle.

Regression Analysis

A binary logistic regression model identified inter-incisor gap (IIG), upper lip bite test (ULBT), neck circumference (NC), and LMAT as independent predictors of difficult laryngoscopy.

Combined Predictive Model

A novel combined predictive model was derived: Ɩ = -0.969 - 1.33×IIG + 0.408×ULBT + 0.201×NC - 0.042×LMAT. This combined model had an AUC of 0.776, exceeding the individual AUC of 0.677 for LMHT.

Study Findings

The study findings suggest that LMHT and the combined predictive model incorporating LMAT are valuable predictors for anticipating difficult laryngoscopy in patients with cervical spondylosis. These radiological indicators can enhance airway management safety by improving preoperative assessment and informing anesthetic planning for this high-risk population.

Key Points

1. The study introduced novel radiological indicators from lateral cervical X-rays in the extended head position to improve the accuracy of predicting difficult laryngoscopy in patients with cervical spondylosis.

2. The radiological indicators analyzed were Mandibular Length (ML), Laryngeal Height (LH), Larynx-Mandibular Angle Test (LMAT), and Larynx-Mandibular Height Test (LMHT).

3. Binary logistic regression analysis identified inter-incisor gap (IIG), upper lip bite test (ULBT), neck circumference (NC), and LMAT as independent predictors of difficult laryngoscopy.

4. A novel combined predictive model was derived, which included IIG, ULBT, NC, and LMAT, and had an AUC of 0.776, exceeding the individual AUC of 0.677 for LMHT.

5. The study findings suggest that LMHT and the combined predictive model incorporating LMAT are valuable predictors for anticipating difficult laryngoscopy in patients with cervical spondylosis.

6. These radiological indicators can enhance airway management safety by improving preoperative assessment and informing anesthetic planning for this high-risk population.

Reference –

Li, J., Tian, Y., Wang, M. et al. Radiological indicators and a novel combined predictive model for anticipating difficult laryngoscopy in cervical spondylosis patients: a prospective cohort study. BMC Anesthesiol 24, 446 (2024). https://doi.org/10.1186/s12871-024-02826-w