## 3 Results  
### Representative Case  
A 31-year-old male patient who underwent segmental mandibulectomy and DCIA iliac crestal free-flap reconstruction for a mandibular defect presented with plate exposure and non-union at the reconstruction site due to the infection of the reconstruction site (Figure 1). Based on the preoperative mandibular CT from the initial lesion, the ideal mandibular form was determined (Figure 2). Reconstruction with a bicortical DCIA flap was planned for the corresponding mandibular position (Figure 3). Surgical guides and customized plates were manufactured according to the preoperative plan, and the reconstruction was performed using these surgical guides and customized plates (Figures 4 and 5). Figure 1: Preoperative panoramic radiograph. Figure 4: 3D-printed customized plates: (**a**) plate for distal segment; (**b**) plate for mesial segment. Figure 3: Virtual surgical planning (VSP): (**a**) alignment of the iliac crestal bone in the mandibular defect; (**b**) design of customized plates. Figure 2: Mandible registration for preoperative planning: (**a**) segmented preoperative mandible; (**b**) alignment of the position of the mandibular segment using the initial lesion model. An accuracy analysis was performed using postoperative CT scans (Figure 6). Reconstruction of the mandible was successful, and no unusual findings were observed during the 6-month follow-up (Figure 7). Figure 5: Intraoperative photo: (**a**) application of iliac bone guide; (**b**) mandible reconstruction with customized plate; (**c**) donor site reconstruction with titanium mesh and allobone chip graft (ReadiGRAFT Cancellous Chips; LifeNet Health, Virginia Beach, VA, USA); (**d**) application of fibrin glue (Greenplast; Green Cross, Yongin, Republic of Korea) after suturing using the internal oblique muscle flap. Figure 6: Post-OP analysis: (**a**) segmented post-OP mandible; (**b**) accuracy results of VSP compared to actual surgical outcomes. A total of five patients were included in this study. The mean age of the patients was 49.6 \(\pm\) 20.5 years (range: 25-73 years), with a gender distribution of three males and two females. The most common diagnosis was ameloblastoma (three cases), followed by an odontogenic keratocyst (one case) and ossifying fibroma (one case) (Table 1). The surgical procedures performed included segmental mandibularomy (two cases), surgical enucleation and peripheral osteotomy (two cases), and marginal mandibularomy (one case). For reconstruction, a bicortical DCIA flap was used in three cases and a monocortical DCIA flap in two cases. The mean span length of the defects was 53.4 \(\pm\) 20.5 mm (range: 29-84 mm). Postoperative complications occurred in one case (20%), which pre \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Age/Sex** & **Diagnosis** & **OP Name** & **Donor Site** & **VSP and Customized Plate Design** & **Span Length (mm)** & **Complications** \\ \hline
1 & 31/M & Ameloblastoma & Segmental & Bicortical & & 62 & - \\  & & & & & & \\  & & & & & & \\  & & & & & & \\
2 & 62/M & Ameloblastoma & & & & & \\  & & & & & & \\  & & & & & & \\
3 & 25/F & Ameloblastoma & & & & & \\  & & & & & & \\  & & & & & & \\
4 & 73/M & Odontogenic & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\
5 & 57/F & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Patient demographics and clinical characteristics. Figure 7: (**a**) Panoramic radiograph 6 months postoperatively; (**b**) clinical photograph 6 months after surgery with complete epithelialization of the internal oblique muscle flap. sented with screw loosening, while the remaining four cases showed no complications. All DCIA flaps achieved successful reconstruction with a 100% survival rate, and no cases of flap failure or vascular complications were observed. The mean operation time was 506.8 \(\pm\) 112.8 min, with the estimated blood loss averaging 430.0 \(\pm\) 218.2 mL. The average hospital stay was 23.2 \(\pm\) 7.8 days.