unlike common long bones , mandible reconstruction presents many difficulties due to its unique shape and relation with dental occlusion and the temporomandibular joint ( tmj ) .
reconstruction plate or non - vascularized autogenous bone graft were used , but were prone to infection and radiation exposure , often resulting in exposure of metal plate and resorption of grafted bone [ 13 ] .
however , there were still difficulties in handling soft tissue and lack of blood supply to grafted bone . with the development of microvascular surgery , free tissue transplantation ( i.e. , deep circumflex iliac artery [ dcia ] , fibular free flap [ fff ] ) transferred sufficient bone and soft tissue with localized blood flow , with greater success in patients previously treated with surgery or radiation .
dcia flap offers large volume and quality of bone tissue for mandibular segmental defects , excellent esthetic shape for reestablishing mandibular continuity , and sufficient height for implant placement .
dcia could be the first choice for reconstruction of segmental mandibular defects of intermediate length ; however , both mandibular resection and iliac crest osteotomy are dependent on the surgeon s experience , intraoperative judgment and technical speed . achieving satisfactory results for contouring the grafted bone and recovering
the occlusion and tmj function has challenged the use of free tissue transfer . to overcome these problems , three - dimensional ( 3d ) computed tomography ( ct ) and computer image processing software
are being used for virtual surgical planning ( vsp ) with resection of lesion and reconstruction of defects , in conjunction with stereolithographic fabrication of surgical guides [ 710 ] .
the majority of computer simulations are used to help restore the neomandible in mandibular reconstruction with fff .
however , the technique is seldom applied in mandibular reconstruction with vascularized iliac crest flap .
the literature is sparse on application of surgery planning and stereo - modeling with a dcia flap , and assessing the postoperative results .
thus , a consistent protocol that approaches the challenging limitations encountered by either by young or experienced surgeons has not been established . herein , the authors suggest a practical protocol for mandible reconstruction based on literature review and our experiences in acquiring satisfactory results using vsp and stereo - lithographic surgical guides .
we achieved satisfactory results with dcia flap with virtual surgery planning and stereolithographic surgical guides .
three patients underwent resection of mandible and accurate mandibular reconstruction with dcia flap using computer simulation and stereomodeling between april 2013 to august 2013 at a single institution .
these patients were three men with an average age of 50 years ( range 3956 years ) .
aesthetic contour , functional outcomes were assessed by dental occlusion , postoperative imaging , and clinical examination .
planning commenced with preoperative high - resolution ct scans from both maxillofacial and pelvic area .
the data was stored as digital imaging communication in medicine format and imported to an image processing software ( mimics software ; materialise , leuven , belgium ) for segmentation of ct images and 3d visualization and planning of lesion safe resection margins , segmental mandibulectomy and design of the reconstructed mandible ( neomandible ) within the iliac bone ( fig .
separately , the dcia were 3-dimensionally reconstructed , analyzed with mevislab ( mevis research , bremen , germany ) and used as surgical reference ( fig .
2 ) . computer - aided design was used to plan the mandibular resection and iliac bone cutting guides with the negative form of the mandibular inferior border ( including the angle area ) and the lateral aspect of the iliac crest ( including the anterior superior iliac spine , asis ) without considering fixation with screws .
the resulting data was saved in stl format for stereolithographic fabrication of the cutting guides and neomandible ( fig .
1c1f ) , which was used to preoperatively bend the reconstruction plate ( fig . 3a ) and assist the double plating technique for preservation of both occlusion and condyle position during surgery .
after adequate mandibular exposure , the reconstruction plate was temporarily positioned in the native mandible to maintain the occlusion and condyles in position .
as the mandibular resection guide was secured in place , osteotomies were performed following the cutting slots , replicating the virtually planned mandibular resection .
the iliac crest was dissected through a lateral approach and a dcia flap was successfully harvested after securing the cutting guide to the lateral aspect of the iliac crest ( fig .
the iliac bone segment was fixed into the mandible defect while the neomandible shape and contour was confirmed .
three patients underwent resection of mandible and accurate mandibular reconstruction with dcia flap using computer simulation and stereomodeling between april 2013 to august 2013 at a single institution .
these patients were three men with an average age of 50 years ( range 3956 years ) .
aesthetic contour , functional outcomes were assessed by dental occlusion , postoperative imaging , and clinical examination .
planning commenced with preoperative high - resolution ct scans from both maxillofacial and pelvic area .
the data was stored as digital imaging communication in medicine format and imported to an image processing software ( mimics software ; materialise , leuven , belgium ) for segmentation of ct images and 3d visualization and planning of lesion safe resection margins , segmental mandibulectomy and design of the reconstructed mandible ( neomandible ) within the iliac bone ( fig .
1 ) . separately , the dcia were 3-dimensionally reconstructed , analyzed with mevislab ( mevis research , bremen , germany ) and used as surgical reference ( fig .
computer - aided design was used to plan the mandibular resection and iliac bone cutting guides with the negative form of the mandibular inferior border ( including the angle area ) and the lateral aspect of the iliac crest ( including the anterior superior iliac spine , asis ) without considering fixation with screws .
the resulting data was saved in stl format for stereolithographic fabrication of the cutting guides and neomandible ( fig .
1c1f ) , which was used to preoperatively bend the reconstruction plate ( fig . 3a ) and assist the double plating technique for preservation of both occlusion and condyle position during surgery .
, the reconstruction plate was temporarily positioned in the native mandible to maintain the occlusion and condyles in position .
as the mandibular resection guide was secured in place , osteotomies were performed following the cutting slots , replicating the virtually planned mandibular resection .
the iliac crest was dissected through a lateral approach and a dcia flap was successfully harvested after securing the cutting guide to the lateral aspect of the iliac crest ( fig .
3 ) . the iliac bone segment was fixed into the mandible defect while the neomandible shape and contour was confirmed .
using mandibular resection and iliac cutting guides , the need for intraoperative measurement was eliminated , allowing exact duplication and positioning of the neomandible with minimal adjustments .
postoperative 3d computed tomographic scans and orthopantography demonstrate faithful replication of preoperative vsp ( fig .
no patients had difficulty in deglutition and speech after surgery and all three are under continuing observation .
osteotomy of dcia flap , introduced by taylor and watson   in 1978 , requires a long operative time to obtain the desired curvature of neomandible and increases the risk of injury to the vascular pedicle , especially for surgeons without much experience .
mandibular reconstruction using virtual surgery planning and stereolithographic surgical guides is a recent introduction , especially in fibula free flaps [ 79,12 ] , but , there are few reports with dcia flap .
for example , although a virtual surgery planning is successfully implemented and a pre - bent reconstruction plate is prepared for the neomandible , to make the 3d shape of the neomandible using fibular or iliac bone flap is dependent on the surgeon s experience   or the mirror image of the opposite side of the mandible   without surgical guides , not considering individual characteristics .
otherwise the reconstruction plate is pre - bent following the native mandible , rather than the neomandible , so it is difficult to achieve close contact between the reconstruction plate and bone flap .
if the screws are tightened for fixation , segments are moving outside and away from each other . considering these problems ,
necessary components of success in exact mandibular reconstruction with minimal errors include accurate vsp , a mandibular resection guide , a donor site cutting guide , and precise fixation of the pre - bent reconstruction plate to neomandible . repeated simulation of the vsp helped to plan optimal osteotomy planes , and to decide which side of the iliac is used and location of vascular pedicle .
the mandibular resection guide yields a reproducible adaptation and stable location without fixation by including the anterior and posterior resection plane and a curved part such as angle or symphysis area .
the iliac cutting guide is also improved for adaptation and location by including the asis area . without screw fixation ,
we can achieve exact location of guides without compromising the blood supply of the donor bone marrow .
in addition , stereolithographic model of neomandible and pre - bending of the reconstruction plate is done to preserve positions of resected mandible and bone flap during fixation .
first , optimal selection of resection plane considering important anatomical structures and the safety margin of the lesion are possible by using virtual simulation surgery of the same size as the patient .
second , preoperative contouring of the reconstruction plate to the planned neomandible model could shorten the operation time and flap ischemia time , improving the flap success rate .
third , achieving plane - to - plane bone contact could be beneficial to bony union , and the functions of tmjs and the occlusion can be preserved . finally , using this technique helps with explanation to patients of problems and challenges of reconstruction . herein , the authors proposed a protocol for mandible reconstruction based on a case - virtual - surgical - plan classification suggested after satisfactory results acquired with dcia flap using vsp and stereolithographic surgical guides ( fig .
the protocol consisted in case categorization into four types of vsp , according to the reconstruction approach ( immediate or delayed ) and condyle preservation described by jewer et al . .
the detailed procedures are chosen by the reconstruction methods such as fff , dcia flap . in type
lc ) and immediate reconstruction , vsp , mandibular resection guide , fibular or iliac cutting guide , and fixation using miniplate by double plating technique with a pre - bent reconstruction plate on the neomandibular model are needed . in type ii cases ,
not preserving condyle ( jewer classification  h ) and immediate reconstruction , vsp , mandibular resection guide , fibular cutting guide , and fixation using a pre - bent reconstruction plate on the neomandibular model are needed . in type iii ,
delayed reconstruction , the condyle is preserved , and the same procedure as other types is performed except for the mandibular resection guide . if the occlusion is to be restored , virtual surgery planning with additional laser cast scan as being applied in orthognathic surgery is used .
mandibular reconstruction with dcia flap by vsp and stereolithographic - guided osteotomy offers an easier , faster and more accurate way to obtain excellent functional and aesthetic results .
high costs and the difficulty of prompt change of resection margins during malignant tumor surgery are shortcomings .
the development of intraoperative model manufacturing for changes of resection plane and the more advanced physical properties of the surgical guides are necessary for better results after surgery .
 purpose : the reconstruction of mandibular defects poses many difficulties due to the unique , complex shape of the mandible and the temporomandibular joints . with development of microvascular anastomosis , 
 free tissue transplantation techniques , such as deep circumflex iliac artery ( dcia ) flap and fibular free flap ( fff ) , were developed . 
 the dcia offers good quality and quantity of bone tissue for mandibular segmental defect and implant for dental rehabilitation . 
 virtual surgical planning ( vsp ) and stereolithography - guided osteotomy are currently successfully applied in three - dimensional mandibular reconstruction , but most use fff . 
 there are only a few articles on reconstruction with the dcia that assess the postoperative results.methods:three patients admitted during a five month period ( april of 2013 to august of 2013 ) underwent resection of mandible and dcia musculo - osseous reconstruction using a vsp and stereolithographic modeling and assessment of outcomes included technical accuracy , esthetic contour , and functional outcomes.results:this technique yielded iliac bone segment with excellent apposition and duplication of the preoperative plan . 
 flap survival was 100 percent and all patients maintained preoperative occlusion and contour.conclusion:based on our experience , we offer considerations and logically consistent protocols by classification of mandibular defects , and demonstrate the benefits in vsp and stereolithographic modeling of mandibular reconstructive surgery with dcia flap . 
Introduction
Materials and Methods
Patients
Virtual surgical planning
Stereolithographic modeling
Surgical technique
Results
Discussion
Conclusion