Retraction force necessary to expose the mandibular neck in Risdon and high cervical anteroparotid transmasseteric approaches: an anatomic comparative study

Purpose The purpose of this anatomic study was to compare the retraction force necessary to expose the mandibular neck in the Risdon and the high cervical anteroparotid transmasseteric (HAT) approaches. Methods An anatomic study was performed on 18 formalin-embalmed cadavers. We performed a Risdon approach on the left side, and an HAT approach on the right side in all the cases. The subjects were placed in a normative frame and the force necessary to maintain a satisfactory exposure of the condyle was measured with a system of cables, pulleys, and mechanical dynamometer. The statistical comparison between the two sides was carried out using the Wilcoxon signed-rank test for paired series. Results In all the cases, the region of interest was exposed as in the operating room. In the Risdon approach, the mean force was 32 Newtons (4-47). In the HAT approach, the mean force was 19 Newtons (4-33). The difference was statistically significant (p < 0.001). The age, gender, and duration of conservation had no influence on the retraction force. Conclusion In the HAT approach, the retraction of the soft tissues was significantly lower than in the Risdon approach. This study gave an additional explanation to the remarkable safety of the HAT approach. Our results were in favor of the generalization of this technique.