The Influence of Mallet Mass and Velocity on the Fracture Patterns in Osteotomies

Osteotomies are routinely incorporated in rhinoplasty, however, the influence of mass, velocity, kinetic energy (KE), and momentum (p) of the mallet on fracture patterns has not been studied.

An experimental sledge guillotine setup was designed simulating a mallet strike with adjustable height and mass and 2 mm-thick Sawbone blocks. KE and p were calculated using KE = ½ mass × velocity² and p = mass × velocity formulas. Fracture lengths and angles were measured.

Ten groups with varying mallet masses and drop heights were tested with 10 bones per group. Fracture length positively correlated with KE (R = 0.542, p < 0.001) and p (R = 0.508, p < 0.001). Fracture angle also positively correlated with KE (R = 0.367, p < 0.001) and p (R = 0.329, p < 0.001). In groups with similar KE, osteotomies with higher p (heavier mallet with slower velocity) had greater fracture lengths (29.31 ± 0.68 vs. 27.68 ± 2.12 mm, p = 0.013) but similar fracture angles (p = 0.189). In groups with similar p, osteotomies with higher KE (lighter hammer with faster velocity) had significantly greater fracture lengths (28.28 ± 1.28 vs. 20.45 ± 12.20 mm, p = 0.041) and greater divergent fracture angles (3.13 ± 1.97° vs. 1.40 ± 1.36°, p = 0.031). Regression modeling of the relationship between KE and fracture lengths and angles demonstrated that cubic followed by logarithmic regression models had the best fits.

Osteotomy fracture patterns positively correlated with the mallet's KE more so than its p, suggesting that the mallet's velocity has an increased impact effect than its mass. Clinically, a heavier mallet with a lower velocity will likely generate a smaller fracture length and fracture angle, indicating a more controlled and ideal fracture.

NA Laryngoscope, 135:97-103, 2025.