Are There Differences in Fracture Patterns in Mandibular Ramus Sagittal Osteotomies Between Hunsuck/Epker, Wolford, and Posnick Modifications?

Abstract

Despite decades of study, the best technique for mandibular ramus sagittal osteotomy has not been definitively determined. The purpose of the present study was to compare fracture patterns, inferior alveolar nerve (IAN) visualization, and torque required for mandibular sagittal splitting using the Hunsuck/Epker, Wolford, and Posnick techniques. This was a laboratory (exvivo), randomized, a single-blind study performed to evaluate sagittal split osteotomies in porcine mandibles using a specifically designed test system. The study's predictor variable was the osteotomy technique, which was divided into 3 groups: Group Hunsuck/Epker (GHE), group Wolford (GW), and group Posnick (GP). The outcome variables were lingual fracture pattern, torque in newtons (N) required to separate the mandible, and IAN visualization. The covariates were mandibular radiodensity and time between dejection and the experiment. The Kolmogorov-Smirnov normality statistics and analysis of variance with Tukey post test statistics were performed. Pvalue <.05 was considered statistically significant. The sample was composed of 120 equally divided porcine hemimandibles in each group. The torque forces were significantly lower (P<.001) when using the Posnick technique (2.07±0.22N) than when using the Hunsuck/Epker technique (4.45±0.32N) and Wolford (3.00±0.21N). GW (93.3%) and GHE (56.7%) showed a higher prevalence of lingual fracture in the posterior region of the mandibular canal (P<.001), while the GP (90%) had a higher frequency of lingual fracture pattern on the mylohyoid sulcus (P<.001). In more than 90% (P<.001) of the mandibles in GW and GHE, the IAN visualization was higher than 50%. In the GP, 90% (P<.001) of patients had IAN visualization of less than 50%. The Posnick technique required less torque to perform the sagittal osteotomy in a pig mandible and had good predictability (90%) for the less preferred lingual fracture pattern and minimal visualization of the nerve. The Wolford technique provided the best predictability (93%) for the preferred lingual fracture pattern and the best nerve visualization. Caution must be exercised when extrapolating the results from animal models to human applications.