Surgical Planning, Three-Dimensional Model Surgery and Preshaped Implants in Treatment of Bilateral Craniomaxillofacial Post-Traumatic Deformities

Surgical Planning, Three-Dimensional Model Surgery and Preshaped Implants in Treatment of Bilateral Craniomaxillofacial Post-Traumatic Deformities

CRANIOMAXILLOFACIAL TRAUMA Surgical Planning, Three-Dimensional Model Surgery and Preshaped Implants in Treatment of Bilateral Craniomaxillofacial Po...

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CRANIOMAXILLOFACIAL TRAUMA

Surgical Planning, Three-Dimensional Model Surgery and Preshaped Implants in Treatment of Bilateral Craniomaxillofacial Post-Traumatic Deformities Junhui Cui, MD,* Lin Chen, MD,y Xiaoguang Guan, DMD,z Lanfeng Ye, DMD,x Hang Wang, MD,k and Lei Liu, MD, PhD{ Purpose:

The purpose of the present study was to explore the treatment and outcomes of bilateral craniomaxillofacial post-traumatic deformities with surgical planning, 3-dimensional (3D) model surgery, and preshaped implants.

Materials and Methods:

We analyzed the preoperative computed tomography (CT) data and designed preliminary surgical plans for 3 patients with bilateral craniomaxillofacial post-traumatic deformities. 3D resin skull models were produced using rapid prototyping technology, and 3D model surgery was performed to determine the location, reduction direction, and shift distance of the osteotomy and to optimize the surgical plans. Titanium plates or mesh were preshaped on the models and then implanted into the patients. The complications, symmetry of the maxillofacial regions, mouth opening, and occlusion were observed 1 month postoperatively.

Results:

The patients had good recovery of their facial contour, occlusion, and mouth opening and acceptable symmetry of the bilateral maxillofacial regions. No complications were observed.

Conclusions: The combination of surgical planning, 3D model surgery, and preshaped implants can provide surgical accuracy and efficiency and good therapeutic outcomes in the treatment of bilateral craniomaxillofacial post-traumatic deformities. Ó 2014 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 72:1138.e1-1138.e14, 2014

Craniomaxillofacial (CM) injuries are often accompanied by life-threatening injuries such as craniocerebral injuries or damage to other important organs.1 For these patients, administering emergency care will be the clinician’s highest priority. Therefore, primary optimal bone reduction and fixation must be postponed, which often results in CM post-traumatic deformities (CMPTDs). The main symptoms of CMPTDs include facial contour deformities, limitation of mouth opening, occlusal dis-

orders, enophthalmos and diplopia, facial nerve injury, nasolacrimal duct obstruction, and external acoustic meatus injury.2 CMPTDs will greatly affect a patient’s physical and mental health and normal social activities. The ultimate goal of treating CMPTD should be to restore the facial esthetics and occlusal function. The only reliable treatment of CMPTD is surgical reconstruction. During surgery, surgeons usually perform bone segmentation, move the bone segments to

Received from Department of Oral and Maxillofacial Surgery, West

Address correspondence and reprint requests to Dr Liu: Depart-

China Hospital of Stomatology, Sichuan University, Chengdu, China.

ment of Oral and Maxillofacial Surgery, West China Hospital of Sto-

*Resident.

matology, Sichuan University, Chengdu 610041 People’s, Republic

yResident.

of China; e-mail: [email protected]

zResident.

Received September 11 2013

xResident.

Accepted February 13 2014

kAssociate Professor. {Professor.

Ó 2014 American Association of Oral and Maxillofacial Surgeons

This study was supported by the Fundamental Research Funds for

http://dx.doi.org/10.1016/j.joms.2014.02.023

0278-2391/14/00234-1$36.00/0

the Central Universities of China (grant 2011SCUD4B14). Drs Cui and Chen were co-first authors.

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their original positions to restore the facial contours, and fix the bone segments with plates and screws. Although surgical accuracy is key in such procedures, CMPTD has usually been caused by old fractures, and the CM skeletal landmarks have often been lost or destroyed. It can be very difficult, and sometimes impossible, to explore the original positions of bone segments in the case of CMPTDs. In the past, surgeons have relied mainly on clinical experience to judge the original positions of bone segments, which often resulted in a poor postoperative facial contour and functional recovery. In patients with unilateral CMPTD, the contralateral side can be used to design a surgical plan to reconstruct the affected side. However, in patients with bilateral CMPTDs, no such reference will exist, and surgical planning becomes difficult. In addition, ensuring that an operation is performed according to the surgical plan will sometimes be more difficult. Thus, the outcomes of surgical treatment of bilateral CMPTDs have often been unsatisfactory. Thus, treatment of bilateral CMPTD continues to be challenging for surgeons. In recent years, digital surgical technologies have provided new approaches for improving the treatment level of CMPTD. D’Urso et al3 compared the outcomes using 3-dimensional computed tomography (3D-CT) combined with a rapid prototyping (RP) model with the use of 3D-CT alone. They found that the combination of 3D-CT and the RP model could significantly reduce the errors in data measurement and improve the accuracy of the surgical plan. Zheng et al4 performed 3D model surgery for mandible reconstruction and found the simulation to be very effective, allowing the design of individual treatment plans and optimal surgical outcomes. Feng et al5 applied mirrorimaging technology and preshaped titanium plates to the treatment of unilateral malar and zygomatic arch fractures and successfully achieved anatomic reduction and good facial symmetry. These studies have demonstrated that CM surgical planning software, 3D model surgery, and preshaped implants can provide effective assistance in the treatment of CM fractures and malformations. Thus far, most studies have investigated unilateral CMPTD, and only a few have focused on bilateral CMPTDs. In the present study, 3 patients with bilateral CMPTDs were treated with surgical planning, 3D model surgery, and preshaped implants. The complications, symmetry of maxillofacial regions, mouth opening, and occlusion were observed 1 month postoperatively.

Materials and Methods The present investigation followed the guidelines provided in the Declaration of Helsinki. The research

ethics board established by the ethics committee of the West China Hospital of Stomatology, Sichuan University, examined the proposed research protocol for this project, which involved the use of surgical planning, 3D model surgery, and preshaped implants in the treatment of bilateral CMPTDs, and found it to be ethically acceptable. Patients with CMPTD were included in the present study from May 2008 to April 2012. The inclusion criteria for the study were patients scheduled to undergo bilateral CMPTD surgery, the timing from injury to presentation of CMPTD was longer than 3 months, and patients who had agreed to participate in the present study. A total of 8 patients were enrolled in the present study initially; however, only 3 patients were followed up 1 month after surgery. The detailed information of the patients is listed in Table 1. The materials used included the following: Philips Brilliance CT 64-slice scanner (Philips, Amsterdam, The Netherlands), SurgiCase, version 4.0 (Materialise, Leuven, Belgium), titanium plate and screw system (Osteomed, Addison, TX), base plate wax (Shanghai Medical Instruments, Shanghai, China), and a RP device (Union Technology, Shanghai, China). PREOPERATIVE PLANNING

For all patients, transverse, coronal, and sagittal CM CT data were obtained. The slice thickness was 1 mm. The CT data were then transferred to SurgiCase for 3D modeling. A preliminary surgical plan was designed, and virtual surgery was performed in SurgiCase. The SurgiCase reconstruction data were imported into the RP device to manufacture 3D resin skull models. Each RP model was produced through radiofrequency carbon dioxide laser sintering of polystyrene powder layer by layer (engineering plastics, particle diameter less than 0.1 mm) in a process that required approximately 20 hours. The models were then sprayed with epoxy resin and treated for 45 minutes with ultraviolet radiation for solidification (Fig 1A). The RP models were used to evaluate the condition of the patients, and 3D model surgery was performed. Osteotomy, reduction, fixation, and reconstruction of facial contours were simulated to validate the direction and distance of osteotomized segment shifts. The preliminary surgical plans were optimized to formulate a final plan from the 3D model surgery, after which the titanium plates or mesh were preshaped on the RP models by placing them across the osteotomy lines and carefully shaping them according to the postreduction bone contours (Fig 1B, C). OPERATIVE TECHNIQUE

The preshaped implants were sterilized using a high-pressure steam sterilizer. All patients were given

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Table 1. PATIENT DEMOGRAPHICS

Variable Gender Age (yr) Injury timing (mo) Preoperative neurologic status Concomitant injuries

Patient 1

Patient 2

Patient 3

Male 18 12 Normal

Male 53 3 Normal

Male 35 12 Normal

Right facial nerve paralysis, right eye blindness

None

Fracture type

Enophthalmos and diplopia, bilateral inner canthus displacement Old NOE fracture

Old bilateral condyle and right mandibular angle and mental fracture

Infection Occlusion Mouth opening (mm)

No Normal 35

Old multiple fractures (bilateral maxilla and zygoma and zygomatic arch, right mandibular angle) No Poor 11

No Poor 18

Abbreviation: NOE, naso-orbitoethmoid. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

general anesthesia with nasotracheal intubation. Depending on the related areas, the operations were performed using hemicoronal, oral vestibular groove, facial scar, and small auxiliary approaches. After full exposure of the surgical regions, osteotomy, reduction, and fixation were performed using the preshaped implants for guidance. The preshaped implants adapted well to the bone surfaces. All operations were accomplished successfully. POSTOPERATIVE DATA PROCESSING

All the patients were followed up at 1 month postoperatively and underwent CT scanning. The 3D-CT data were transferred to SurgiCase for 3D modeling. The pre- and postoperative symmetry, mouth opening, and occlusion were used to evaluate the surgical outcome.

Results POSTOPERATIVE EXAMINATION

At 1 month postoperatively, no infection or plate exposure was observed in any of the patients. The enophthalmos and diplopia of the patients with old naso-orbitoethmoid (NOE) fractures were alleviated significantly, and the inner canthus displacement had been abolished. All 3 patients underwent CT scanning, and the CT data were transferred to SurgiCase for 3D modeling. The CT data, SurgiCase 3D model, and facial contours revealed that all the patients had regained acceptable symmetry, acceptable mouth opening, and acceptable occlusion.

COMPARISON BETWEEN PRE- AND POSTOPERATIVE DATA

The symmetry was evaluated mainly using SurgiCase by measuring the distance from the selected marker points to the reference planes. The reference planes were established according to the highest midpoint on the roof of the external auditory meatus (Po), lowest point on infraorbital margin of each orbit (Or), and midpoint between the left Po and right Po. Three reference planes were established as follows: horizontal plane (HP): the plane through the left Po, right Po, and Or; coronal plane: the plane through the left Po and right Po and perpendicular to the HP; sagittal plane: the plane through the midpoint between the left Po and right Po and perpendicular to the HP (Fig 2A-C). The intersection point of the zygomaticomaxillary suture and the infraorbital margin, the most anterior point of the zygoma, the most inferior point of the temporozygomatic suture, the most lateral point of gonion area, the most lateral point at the anterior border of ramus, and the most superior point of the condyle head were chosen as the marker points (Fig 2D). A representative patient with CMPTD because of old NOE fractures was treated using surgical planning, 3D model surgery, and preshaped implants methods. The preoperative 3D-CT data from the patient were imported into SurgiCase for 3D modeling. Next, the original head model was manufactured using a RP device (Figs 1A, 3A-C). On the model, titanium mesh was shaped before surgery on the wax guide plate (Fig 1B, C). The postoperative 3D-CT data, 3D modeling,

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FIGURE 1. Preoperative planning for patients with craniomaxillofacial post-traumatic deformity. A, Resinous craniofacial model manufactured using a rapid prototyping device. B, C, Preshaping of titanium mesh or plates on rapid prototyping models. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

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FIGURE 2. Reference planes and marker points for symmetry valuation. A, Horizontal plane (HP). B, Coronal plane (CP). C, Sagittal plane (SP). D, Marker points: a, indicates the distance to HP; b, the distance to SP; and c, the distance to CP. Cd, most superior point of the condyle head; Go, most lateral point of the gonion area; Ma, most anterior point at lateral border of ramus; Mp, most anterior point of the zygoma; Oz, intersection point of the zygomaticomaxillary suture and the infraorbital margin; Ztl, most inferior point of the temporozygomatic suture. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

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FIGURE 3. Preoperative and postoperative comparison for a patient with craniomaxillofacial post-traumatic deformity caused by old nasoorbitoethmoid fractures. A, Preoperative 3-dimensional (3D) computed tomography data. B, C, Computed tomography (CT) data were imported into SurgiCase for 3D modeling. D, Postoperative 3D-CT data. (Fig 3 continued on next page.) Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

and photograph view revealed successful surgical reduction and fixation and acceptable symmetry in the bilateral maxillofacial regions (Fig 3D-L). Similarly, patients with CMPTD because of old multiple fractures in the maxillofacial region and patients with CMPTD because of old bilateral mandibular fractures were treated using the same surgical protocol. The results indicated that the maxillofacial symmetry of the 2 patients had recovered satisfactorily (Figs 4A-F, 5A-F). Furthermore, the 2 patients had regained normal

mouth opening and occlusion (Figs 4G, H, 5G, H). In addition, the difference in the value of the distance from the mark points to the reference planes for bilateral sides and the quantitative mouth opening are listed in Tables 2 and 3.

Discussion Reconstructive surgery of CM deformities has been challenging for surgeons. In recent decades, digital

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FIGURE 3 (cont’d). E, F, Postoperative CT data were imported into SurgiCase for 3D modeling. G,H, Preoperative and postoperative views of the patient at 1 month postoperatively. (Fig 3 continued on next page.) Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

surgical technologies6-8 have been rapidly developing and have led to improved surgical planning and operation implementation. These technologies, which have included virtual surgical planning, RP technology, and digital surgical navigation technology, have had broad applications in liver surgery,9 cardiothoracic surgery,10 neurosurgery,11 and, especially, oral and maxillofacial surgery. According to D’Urso et al,3 ‘ Every patient is unique. Thus, there is always a need for the surgeon to attain a specific understanding of the individual’s anatomy pre-

operatively.’’ Therefore, for decades, many investigators have tried to find better technologies to provide individual treatment schemes for patients. Advances in radiography (spiral CTand 3D imaging) have greatly enhanced the accurate diagnosis and preoperative planning. However, the traditional image-reading mode has not met surgeons’ requirements. Researchers have therefore combined radiologic imaging technology and computer processing technology. Interactive software was developed to assist surgeons in analyzing and measuring the operative regions more directly and in designing the

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FIGURE 3 (cont’d). I-L, Preoperative and postoperative views of the patient at 1 month postoperatively. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

individual surgical plans. SurgiCase, an interactive software program using CT data, was designed to use CM anatomic measurements and surgical planning to predict the surgical outcomes. Marchetti et al12 reported that SurgiCase could increase the accuracy in orthognathic surgical planning. Roser et al13 applied SurgiCase successfully to mandibular reconstruction and achieved a reasonably high level of accuracy in mandibular and fibular osteotomies through the use of the surgical cutting guides. We therefore chose SurgiCase to assist in the treatment of CMPTD in the present study and found

that SurgiCase could measure CM areas accurately, assist surgical planning effectively, and predict surgical outcomes. However, because of the complexity of maxillofacial 3D structures, the use of SurgiCase alone for surgical planning could sometimes not achieve a satisfactory therapeutic effect, primarily because of some limitations in virtual simulation. First, the reference plane will sometimes be imprecise because most CM landmarks will have been lost in a complex CMPTD. Second, the virtual 3D model was displayed as a 2-dimensional

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FIGURE 4. Treatment of a patient with craniomaxillofacial post-traumatic deformity caused by old multiple fractures in the maxillofacial region using surgical planning, 3-dimensional model surgery, and preshaped implant methods. A, Preoperative computed tomography (CT) data for 1 patient with multiple fractures in the maxillofacial region. B, Preoperative CT data were imported into SurgiCase for 3D modeling. C, Original skull model manufactured using a rapid prototyping device. D, Titanium plates were shaped on the original skull model and implanted in the patient. (Fig 4 continued on next page.) Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

object on a 2-dimensional screen. Although it can be simulated and seen from different angles, it cannot provide the sensation of real feedback for surgical planning and simulation. Third, the translation from the virtual model to the actual operation, and the repeatability of virtual planning requires validation and optimization of the preliminary virtual plan. 3D model surgery is a preoperative planning process using RP models.14-16 It

allows surgeons to rehearse procedures on the RP model to validate and optimize the virtual surgery plan and to obtain more predictable reconstruction outcomes. Therefore, 3D model surgery was still needed by the surgeons. In the past, limitations existed when analyzing the spatial relationships of bony structures accurately, especially when facial asymmetry was present.

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FIGURE 4 (cont’d). E, Postoperative CT data. F, Postoperative CT data were imported into SurgiCase for 3D modeling. G, Preoperative mouth opening of the patient. H, Postoperative mouth opening of the patient. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

Surgeons could rely only on visual estimation and clinical experience. However, 3D model surgery can help surgeons to plan a more feasible surgical procedure to achieve better therapeutic effects. It provides an intuitive method to measure asymmetry-related discrepancies on the model and an opportunity to study the individual bony structures of the patient and perform any required surgical maneuvers before the actual surgery. In addition, the use of 3D model surgery can

shorten the operative time, because such timeconsuming processes as the adaptation of implants can now be performed on the model before surgery. Cohen et al17 found that 3D model surgery could assist in accurate contouring of the plates before surgery and provided a precise, fast, and mandibular reconstruction, aiding in a shortened operative duration. Heissler et al18 used RP technology to produce implants for reconstruction of cranial defects. They first built an

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FIGURE 5. Treatment of a patient with craniomaxillofacial post-traumatic deformity caused by old bilateral mandibular fractures using surgical planning, 3-dimensional (3D) model surgery, and preshaped implant methods. A, Preoperative 3D-computed tomography (CT) data for 1 patient with old bilateral mandibular fractures. B, Preoperative CT data were imported into SurgiCase for 3D modeling. C, Original head model manufactured using a rapid prototyping device. D, Titanium plates were shaped before surgery on the original head model. (Fig 5 continued on next page.) Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

RP model of the defect and then used it to cast titanium implants that were much more accurate than those produced by conventional milling. In the present study, all patients had bilateral CMPTDs. The common feature of these patients was facial asymmetry. 3D model surgery was used to ensure accurate osteotomy location and shift distance of the bone segments, which was important in deter-

mining the final surgical plan. Even with a perfectly designed surgical plan, inaccurate implant placement intraoperatively can still cause postoperative complications. Accurate transfer of the preoperative surgical plan into the operating room, which has continued to be a major challenge to surgeons, can be accomplished as follows: templates, surgical navigation, and preshaped implants. Each has had some limitations.

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FIGURE 5 (cont’d). E, Postoperative CT data. F, The postoperative CT data were imported into SurgiCase for 3D modeling. G, Preoperative occlusion. H, Postoperative occlusion. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

The template is an effective method of translating a preoperative plan to real surgery. However, the template was usually large, and surgeons must perform extensive stripping in the operative region. This can result in extra injury and can have a negative effect on bone healing. In addition, the production of repositioning templates has been expensive. Surgical navigation technology will be most suitable for surgery in the CM deep regions, such as orbital floor reconstruction, parapharyngeal foreign body removal, and radiofre-

quency thermocoagulation of the trigeminal nerve root. Surgical navigation does not require extra exposure or a template during surgery. However, it is not well suited to complex CMPTDs. Preshaped implants will be best for complex deformities requiring treatment with titanium plates and mesh and do not require extra stripping, such as that required by templates. Also, the preshaping of implants can be performed preoperatively; thus, the operative duration can be shortened. Ciocca et al19 successfully applied preshaped

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Table 2. DIFFERENCE IN DISTANCE FROM MARK POINTS TO REFERENCE PLANES FOR BILATERAL SIDES

Preoperative (mm) Pt. No.

Postoperative (mm)

Mark Point

Inward

Backward

Downward

Oz Mp Ztl Go Cd Ma Oz Mp

2.84 1.07 1.16 0.15 0.03 0.04 2.78 1.46

2.96 1.58 0.95 0.13 0.17 0.14 1.84 1.37

3.17 1.23 1.04 0.15 0.15 0.16 3.17 2.32

Ztl Go Cd Ma Oz Mp

3.45 4.78 17.7 6.34 0.08 0.17

2.79 3.73 2.56 3.56 0.04 0.05

Ztl Go Cd Ma

0.12 3.31 2.15 3.25

0.13 2.73 2.19 2.67

Inward

Backward

Downward

1.51 0.87 0.97 0.16 0.03 0.06 1.78 1.25

1.55 1.09 1.05 0.13 0.18 0.16 0.84 1.46

1.63 0.81 1.04 0.17 0.13 0.17 2.95 1.28

2.13 3.04 3.87 2.75 0.07 0.08

2.43 2.33 4.35 1.65 0.10 0.17

1.26 1.48 1.41 1.54 0.04 0.08

1.11 2.37 1.42 1.57 0.09 0.10

0.06 2.08 1.12 2.09

0.11 1.21 1.34 1.26

0.90 1.27 1.79 1.16

0.09 1.31 0.95 1.19

1

2

3

Abbreviations: Cd, most superior point of the condyle head; Go, most lateral point of the gonion area; Ma, most anterior point at lateral border of ramus; Mp, most anterior point of the zygoma; Oz, intersection point of the zygomaticomaxillary suture and the infraorbital margin; Pt. No., patient number; Ztl, most inferior point of the temporozygomatic suture. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

implants in mandibular reconstruction using a custommade bone plate connected to a computer-aided design/computer-aided manufacturing, prototype anatomic condylar prosthesis to support a fibular free flap. The custom-made plates represent a viable method to restore the facial contour, give the surgeon better procedural control, and reduce the operative time. Feng et al5 used preshaped titanium plates to treat unilateral malar and zygomatic arch fractures successfully, and all patients had good therapeutic effects. In the present study, we chose preshaped implants to assist in the accurate and successful translation of the surgical plans into actual operations, which resulted

in patients regaining their facial symmetry and normal occlusal function. In conclusion, the results of the present study have demonstrated that combination of surgical planning, 3D model surgery, and preshaped implants can provide surgical accuracy and efficiency and good therapeutic outcomes in the treatment of bilateral CMPTD. Acknowledgments We thank the patients and their families for their participation in our study. We would like to extend special thanks to the Materialise Group for providing the trial version of the SurgiCase software.

References Table 3. MAXIMAL INTERINCISIONAL OPENING

Pt. No. 1 2 3

Preoperative (mm)

Postoperative (mm)

35 11 18

34 25 22

Abbreviation: Pt. No., patient number. Cui et al. Bilateral CMPTD Treatment. J Oral Maxillofac Surg 2014.

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CUI ET AL 5. Feng F, Wang H, Guan X, et al: Mirror imaging and preshaped titanium plates in the treatment of unilateral malar and zygomatic arch fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 112:188, 2011 6. Xia J, Ip HH, Samman N, et al: Computer-assisted threedimensional surgical planning and simulation: 3D virtual osteotomy. Int J Oral Maxillofac Surg 29:11, 2000 7. Liu X, Gui L, Mao C, et al: Applying computer techniques in maxillofacial reconstruction using a fibula flap: A messenger and an evaluation method. J Craniofac Surg 20:372, 2009 8. Collyer J: Stereotactic navigation in oral and maxillofacial surgery. Br J Oral Maxillofac Surg 48:79, 2010 9. Saito S, Yamanaka J, Miura K, et al: A novel 3D hepatectomy simulation based on liver circulation: Application to liver resection and transplantation. Hepatology 41:1297, 2005 10. Cakar F, Werner P, Augustin F, et al: A comparison of outcomes after robotic open extended thymectomy for myasthenia gravis. Eur J Cardiothorac Surg 31:501, 2007 11. Spicer MA, van Velsen M, Caffrey JP, et al: Virtual reality neurosurgery: A simulator blueprint. Neurosurgery 54:783, 2004 12. Marchetti C, Bianchi A, Muyldermans L, et al: Validation of new soft tissue software in orthognathic surgery planning. Int J Oral Maxillofac Surg 40:26, 2011

1138.e14 13. Roser SM, Ramachandra S, Blair H, et al: The accuracy of virtual surgical planning in free fibula mandibular reconstruction: Comparison of planned and final results. J Oral Maxillofac Surg 68: 2824, 2010 14. Whitman DH, Connaughton B: Model surgery prediction for mandibular midline distraction osteogenesis. Int J Oral Maxillofac Surg 28:421, 1999 15. Winder J, Bibb R: Medical rapid prototyping technologies: State of the art and current limitations for application in oral and maxillofacial surgery. J Oral Maxillofac Surg 63:1006, 2005 16. Spagnoli DB: The use of stereolithographic models in oral and maxillofacial surgery. J Oral Maxillofac Surg 61:9, 2003 17. Cohen A, Laviv A, Berman P, et al: Mandibular reconstruction using stereolithographic 3-dimensional printing modeling technology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 108: 661, 2009 18. Heissler E, Fischer FS, Boiouri S, et al: Custom-made cast titanium implants produced with CAD/CAM for the reconstruction of cranium defects. Int J Oral Maxillofac Surg 27:334, 1998 19. Ciocca L, Mazzoni S, Fantini M, et al: A CAD/CAM-prototyped anatomical condylar prosthesis connected to a custom-made bone plate to support a fibula free flap. Med Biol Eng Comput 50:743, 2012