Secondary Mandible Reconstruction with Computer-Assisted-Surgical Simulation and Patient-Specific Pre-Bent Plates: The Algorithm of Virtual Planning and Limitations Revisited

Abstract

Despite the known advantages of virtual surgical planning and three-dimensional (3D) printing, translation of virtual planning to actual operation is a challenge, especially in secondary mandibular reconstruction. Patients who underwent secondary microvascular mandibular reconstruction were retrospectively reviewed and categorized into three categories as follows: (i) defect not crossing the midline (category I); (ii) defects crossing the midline with availability of previous imaging data (category II) and; (iii) defects crossing the midline with unavailability of previous imaging data (category III). The resulting 3D printed models were used as an effective guide for plate bending during secondary reconstruction surgery. Accuracy of the reconstruction was evaluated by superimposing post-operative images over virtual plan. Out of eleven patients, five were category I, three were category II, and three were category III. The mean linear discrepancy between the planned and post-operative position was measured. A Mann-Whitney U test was conducted to compare mean discrepancy among the groups showed no significant difference between group I and group II (p > 0.05) whereas comparison of groups I and II with group III showed a significant difference (p < 0.01). The proposed algorithm for the generation of defect template for manual plate bending during secondary reconstruction of mandibular defects is valid with acceptable accuracy in various defect configurations.

Keywords

• mandibular defect
• plate bending
• secondary reconstruction
• virtual surgical planning (VSP)
• vascularized bone flap
• 3D printing