## 3 Discussion  
As microvascular anastomosis techniques become more sophisticated and microsurgical instruments are developed, reconstruction using free flaps for oral and maxillofacial defects is the best option [22]. There is a disadvantage in that the plate is fractured and exposed when using a reconstruction plate, and soft tissue for reconstruction in a long-term prognosis [23; 24]. In addition, reconstruction using plates has some limitations. It cannot be used for complex defects, such as defects involving soft tissue and hard tissue [5]. In these cases, the hard tissue and additional soft tissue must be treated simultaneously. The oral cavity has a variety of masticatory muscles and facial expression muscles, and it moves to perform various functions, such as emotional expression, mastication, or pronunciation. For this reason, when oral defects are directly reconstructed with a plate, various complications may occur, such as plate exposure, infection, and loosening of the fixing screw [5]. Moreover, it is challenging to recover masticatory function when reconstruction uses a reconstruction plate [5]. On the other hand, the osseous-free flap achieves long-term survival through normal bone remodeling by osseointegration with the existing bone tissue within 2\(\sim\)3 months [25]. Reconstruction using free vascularized flaps provides an environment similar to normal oral tissue, which changes naturally with the surrounding bone tissue, enabling the remodeling of the occlusion using implant placement, bone grafting, removal,  
Figure 11: Radiograph of left illum; fracture line on iliac donor site was seen. Figure 10: Initial examinations: (**a**) intraoral photograph showed the proliferative lesion with indistinct borders on the right upper gingiva; (**b**) panoramic view. and replanting [5]. Therefore, vascularized free flaps using hard and soft tissues are mainly used, and the use of reconstruction plates is becoming a secondary option [5]. Donor sites used mainly for jaw reconstruction include the fibula, iliac crest, and scapula [21]. Each donor site differs in the amount and quality of bone and soft tissue available, as well as the volume of the vascular pedicle, and the availability of the two-team approach. The surgeon should consider several factors and choose the best treatment option for the patient and surgical outcome [26]. [PERSON] and [PERSON] first introduced the DCIA flap in 1979 [27; 28]. In 1989, [PERSON] first used a combination of iliac crest bone and internal oblique muscle to reconstruct an oral and maxillofacial defect. The iliac crest flap has been used to reconstruct oral and maxillofacial defects due to good bone quality and sufficient soft tissue [29]. However, DCIA flaps have also reported various donor-siteorbidities. [PERSON] and [PERSON] reported a hernia on a DCIA donor site [30; 31]. [PERSON] and [PERSON] reported on DCIA flaps considering the possibility of gait disturbance and hip contour defects when harvesting a large amount of the iliac bone [32]. Research on how to prevent donor-site morbidity that can occur in DCIA flaps has also been conducted in various ways. Using a monocritical DCIA flap while preserving the ASIS minimized tissue defects in support of the donor site, thereby minimizing complications caused by bone weakness [7]. [PERSON] et al. used Protack (titanium tacks) and Prolene (polpropylene mesh) to prevent a hernia due to the reconstruction of bone defects in the donor site [33]. [PERSON] proposed a method of repairing bone defects using a 0.4 mm thick titanium sheet [34]. In this report, we proposed an open-reduction method using a patient-specific, 3D-printed titanium implant. This method restored the ilium as closely to the original shape of the patient's iliac bone as possible using the pre-harvested CT data. The patient-specific titanium implant presented in our study can be manufactured in a size as similar as possible to the size of the fracture site and the peripheral bone defect site.