The Callender modification of the Macintosh laryngoscope blade reduces the risk of tooth-blade contact in children

Background: Dental injury is well recognized as a potential complication of laryngoscopy and tracheal intubation. The flange of the Macintosh blade may contact teeth during laryngoscopy causing damage. The Callander modification of the Macintosh blade (Callander blade) with a shortened heel at the proximal end has been shown to increase the blade–tooth distance and reduce contact rates in adults. Aim: This study was designed to evaluate the effectiveness of the Callander blade on reducing dental contact in children. Methods: One hundred children, aged 4–14 years, scheduled for general anesthesia requiring endotracheal intubation were studied prospectively. The children were preoperatively evaluated for Mallampati score and dental defects, looseness, and avulsions. Following induction of anesthesia, laryngoscopy was performed twice on each child in succession, once with a standard Macintosh blade and once with a Callander blade of the same size in a random order. The blade–tooth distance and contact rate were compared between the two blades. Results: With the Callander blade, the blade–tooth distance was greater than with the Macintosh (1.78 ± 1.77 vs 0.28 ± 0.76 mm, P = 0.001). The frequency of direct contact was less with the Callander blade than it was with the Macintosh blade (33% vs 86%, respectively, P = 0.008). However, difficult laryngoscopy rate did not differ between the blades. Tracheal intubation was successful in all children and there was no dental injury. Conclusion: Our findings suggest that the Callander blade decreases the risk for dental injury and provides tracheal intubating conditions in children with normal airways similar to those obtained with a traditional Macintosh blade.