How accurate is computer-assisted mandible gunshot wound management by patient-specific distraction device? Preoperative planning versus postoperative outcomes.

Gunshot wounds of the lower face are a challenge for the surgeon. Customized distraction osteogenesis (DO) is a well-established procedure for managing facial gunshot wounds. However, differences between the preoperative planning and postoperative outcomes are often noted. This multi-centre, retrospective study was performed to analyse the differences between the planning and outcomes for the lower third of the face, in patients undergoing the computer-assisted repair of mandible gunshot wounds using patient-specific distraction devices. Different planes and points were defined, and two distances (anteroposterior and intercondylar lengths) and an angle (inter-mandible body angle) were measured on the preoperative planning models and the postoperative models obtained from the computed tomography data. Twelve patient cases that met the study eligibility criteria were included. A significant difference between the planning and postoperative outcome was found for the anteroposterior length (6.6 mm shorter than the preoperative planning; P = 0.003). The differences in intercondylar length (P = 0.116) and inter-mandible body angle (P = 0.121) were not significant. This study revealed a difference between the planning and outcomes. Various factors such as scar tissue and muscle forces limit distraction and therefore lead to under-correction with insufficient projection.