Special considerations in virtual surgical planning for secondary accurate maxillary reconstruction with vascularised fibula osteomyocutaneous flap

A new concept for mandible reconstruction after oncological resection: Multisegment virtual surgical planning

PURPOSE

Virtual surgical planning (VSP) is good for three dimensional reconstructions in maxillofacial surgery, but it is not problem-free completely especially when the resection margins cannot be affirmed in preoperative period. We aimed to obtain an ideal reconstruction with elaborating VSP to be prepared for adverse conditions during surgery and to proceed the oncological resections step- by- step with A, B, and C resection planes.

PATIENTS AND METHODS

Four patients undergoing multisegment VSP for the primary mandible malignancies were included in the study. The first resection margin was detected as plan A in VSP, and plans of B and C were also prepared considering the tumor- positive result of intraoperative frozen section procedure.

RESULTS

Following the tumor resection, margins were extended to the plan B in two patients, and plan C in one patient in accordance with the results of the frozen section procedure.Histogram comparison of the localizations of osteotomies in mandible and fibula, and positions of the implants were calculated at a confidence level of 95 % (p > 0.95) and mean difference was found -0.55 mm, while standard deviation was 1.76 mm.

CONCLUSION

Multisegment virtual surgical planning seems to achieve the optimal reconstruction with the staged resection preventing redundant removal of tumor- free structures like bone and teeth.

Multiple Buttresses Reconstruction of Maxilla with Fibular Flap Using Computer-aided Design/Computer-aided Manufacturing after Maxillectomy

Background

The maxilla comprises horizontal and vertical buttresses, each with specific functions, supporting various organs, such as the eyes, nose, and oral cavity. Notably, they combine to form a three-dimensional structure, which enables the buttresses to provide their inherent support strength. However, reconstructing the maxilla after maxillectomy by assembling new buttresses is challenging. We successfully reconstructed all the buttresses crucial for facial appearance and dental rehabilitation using a vascularized fibular flap.

Methods

Four patients underwent maxillary buttress reconstruction with a fibular flap after total or subtotal maxillectomy. We used computer-aided design/computer-aided manufacturing digital technology to osteotomize the fibula into multiple segments and assemble them to reconstruct the maxillary buttresses. Each buttress was assembled based on a preoperative simulation.

Results

All patients underwent immediate one-stage maxillary reconstruction. They had good maxillary buttress alignment and acquired good facial appearance, eye position, nasal airway, and prosthetically suitable maxillary alveolus ridge.

Conclusions

The combination of computer-aided design/computer-aided manufacturing digital technology and surgical techniques has enabled novel maxillary reconstruction, providing great hope to patients experiencing facial disfigurement and loss of function after maxillectomy.

The comparison between various methods of mandibular reconstruction based on finite element analysis

The Mandible can be damaged by pathological factors, tumors, trauma, infection, and needs a surgical operation for reconstruction and restoring function. There are different methods for the reconstruction of mandible. Based on the surgical approach, primary reconstruction of mandible by reconstruction plate after resection is necessary for maintaining mandibular symmetric and esthetic of the lower third of the face. A finite element model of mandible and masticatory muscles was produced from a normal person (male with 35-year-old). The normal model was resected from the left sixth tooth to the second tooth. The pathological model was reconstructed in different conditions by macro plate. Different conditions were analyzed and compared based on bite force on right fifth tooth, stress developed on screws and macro plate. The finite element analysis results showed that maximum bite force and lower stress on screws were seen in the pathological model (condition 5) when one macro plate and six screws were inserted in the mid-body. The findings showed that the use of two macro plates causes lower stress on it than when we use one. Use of one macro plate and six screws is the best choice in mandibular immobilization which decrease the stress applied on bone and increase the bite force. Because of less stress developed on macro plates and screws, use of two macro plates or one macro plate in mid-body area are also preferred.

Simplified Virtual Surgical Planning Method for Reconstruction of Secondary Maxilla and Mandibular Defects Using Free Bone Flap

Objective

Free fibula flap is the commonly used microvascular free tissue transfer for maxillary and mandibular reconstruction to restore form and function after ablative procedures. Bony reconstruction is an important aspect of reconstruction. This paper describes our technique in using virtual surgical planning for secondary reconstruction of the maxilla and mandible using only stereolithographic models.

Discussion

In the recent past, virtual surgical planning has become a game changer in planning complex reconstruction of maxilla and mandible. This becomes even more important in the cases of secondary reconstruction. Virtual surgical planning requires close interaction between the surgeon and the design and manufacturing team. The latter is often done remotely making the process cumbersome and less user friendly. We have been using a simplified version of the virtual surgical planning at a low cost set up with effective outcomes. This report consists of 22 cases in which secondary reconstruction using osteo-cutaneous free fibula flap was carried out using virtual surgical planning. Mock surgery was performed on stereolithographic (STL) models (face and fibula), pre-bending of plates and fabrication of occlusal splints helped in precise translation of the treatment plan to the operating room which in turn helped in reducing the surgical time and attaining more predictable results.

Conclusion

Secondary reconstruction of maxilla and mandible is complex and requires meticulous planning to achieve optimal and predictable results which directly improves the quality of life of the patients.

Aesthetic reconstruction of onco-surgical maxillary defects using free scapular flap with and without CAD/CAM customized osteotomy guide

BACKGROUND

Reconstruction of the maxillary defects following tumor ablation remains to be a challenge for surgeons. Virtual surgical planning (VSP), intraoperative cutting guides and stereolithographic models provides the head and neck reconstructive surgeon with powerful tools for complex reconstruction planning. Despite its use in fibular osteocutaneous reconstruction, application to the scapular free flap has not been as widely reported. The aim of this study was to compare aesthetic results and operation time of free scapular flap, with and without computer-aided design and computer-aided manufacturing (CAD/CAM) customized osteotomy guide, for reconstruction of maxillary defects.

METHODS

In this prospective randomized controlled clinical trial study, we randomly assigned 22 patients with maxillary defects who were scheduled to undergo maxillary reconstruction with either free scapular flap with CAD/CAM customized osteotomy guide; study group (n = 11) or free scapular flap without CAD/CAM customized osteotomy guide; control group (n = 11). All patients were followed up for 3 months. The aesthetic outcome, operation and ischemic times were evaluated and compared.

RESULTS

Aesthetic outcomes were evaluated objectively by means of differential surface area (sagittal and axial) measurement, which showed improved aesthetic outcome (contour symmetry) in the study group with a mean of (241.39 ± 113.74 mm²), compared to patients in control group with a mean of (358.70 ± 143.99 mm²). There were significant differences between the two groups (P < 0.05). Aesthetic outcomes were also evaluated subjectively by means of visual analogue scale (VAS) and patient's satisfaction score (PSS). The postoperative aesthetic appearance was better in the study group with more patients satisfied than that in control group and there were statistically significant differences (P = 0.039). The mean total operative time was 678.81 min and 777.18 min in the study group and control group respectively (P < 0.05) and the mean ischemia time was 133.18 min and 195.72 min for study group and control group respectively (P < 0.05). The ischemia time and total operative time were shorter in the study group compared to those in the control group and there were no flap losses in both groups.

CONCLUSION

The use of CAD/CAM prefabricated cutting guides facilitates scapular flap molding and placement, minimizes ischemic time and operating time as well as improves aesthetic outcomes. Trial registration This trial was registered at ClinicalTrials.gov.

REGISTRATION NUMBER

NCT03757286. Registration date: 28/11/2018.

The state of virtual surgical planning in maxillary Reconstruction: A systematic review

Virtual surgical planning (VSP) and computer aided design utilization in head and neck reconstruction has become increasingly popular within the discipline. Advocates of the technology over traditional free hand surgery cite benefits including improved intraoperative efficiencies and postoperative outcomes that have been demonstrated during mandibular reconstruction. More recently, VSP for maxillary and mid facial reconstruction, generally considered more complex than their mandibular counterparts, have been applied with the hopes of similar benefits. However, our literature search revealed no large-scale randomized control trial substantiating these benefits. As such, the aim of this review was to synthesize the existing research on utilization of VSP in the context of maxillary reconstruction. Three databases were systematically searched for articles pertaining to maxillary reconstruction for oncologic, traumatic, or osteoradionecrosis indications. Four hundred and fourteen unique articles were reviewed by two independent reviewers ultimately revealing sixteen studies appropriate for qualitative synthesis including 142 patients. Results of our studies reveal the extreme heterogenicity of application of this technology under the label of virtual surgical planning. Outcome reporting methods were grossly inconsistent amongst all the articles resulting in inability to appropriately synthesize data quantitatively for a meta-analysis. Overall, there was no standard of reporting outcomes of maxillary reconstruction, and no randomized trials comparing virtual surgical planning versus freehand surgery and therefore there is insufficient data to objectively prove purported benefits. To facilitate future comparative studies, a minimal standard of reporting for maxillary VSP is presented and the need for a randomized control trial is highlighted.

Unraveling of Advances in 3D-Printed Polymer-Based Bone Scaffolds

The repair of large-area irregular bone defects is one of the complex problems in orthopedic clinical treatment. The bone repair scaffolds currently studied include electrospun membrane, hydrogel, bone cement, 3D printed bone tissue scaffolds, etc., among which 3D printed polymer-based scaffolds Bone scaffolds are the most promising for clinical applications. This is because 3D printing is modeled based on the im-aging results of actual bone defects so that the printed scaffolds can perfectly fit the bone defect, and the printed components can be adjusted to promote Osteogenesis. This review introduces a variety of 3D printing technologies and bone healing processes, reviews previous studies on the characteristics of commonly used natural or synthetic polymers, and clinical applications of 3D printed bone tissue scaffolds, analyzes and elaborates the characteristics of ideal bone tissue scaffolds, from t he progress of 3D printing bone tissue scaffolds were summarized in many aspects. The challenges and potential prospects in this direction were discussed.

Mandibular Reconstruction With Fibula Flap and Dental Implants Through Virtual Surgical Planning and Three Different Techniques: Double-Barrel Flap, Implant Dynamic Navigation and CAD/CAM Mesh With Iliac Crest Graft

Introduction

Vertical discrepancy between the fibula flap and the native mandible results in difficult prosthetic rehabilitation. The aim of this study was to evaluate the outcomes of 3D reconstruction of the mandible in oncologic patients using three different techniques through virtual surgical planning (VSP), cutting guides, customized titanium mesh and plates with CAD/CAM technology, STL models and intraoperative dynamic navigation for implant placement. Material and methods

Material and Methods

Three different techniques for mandibular reconstruction and implant rehabilitation were performed in 14 oncologic patients. Five patients (36%) underwent VSP, cutting guides, STL models and a customized double-barrel titanium plate with a double-barrel flap and immediate implants. In six patients (43%), VSP, STL models and a custom-made titanium mesh (CAD/CAM) for 3D reconstruction with iliac crest graft over a fibula flap with deferred dental implants were performed. Three patients (21%) underwent VSP with cutting guides and customized titanium plates for mandibular reconstruction and implant rehabilitation using intraoperative dynamic navigation was accomplished. Vertical bone reconstruction, peri-implant bone resorption, implant success rate, effects of radiotherapy in vertical reconstruction, bone resorption and implant failure, mastication, aesthetic result and dysphagia were evaluated.

Results

Significant differences in bone growth between the double-barrel technique and iliac crest graft with titanium mesh technique were found (p<0.002). Regarding bone resorption, there were no significant differences between the techniques (p=0.11). 60 implants were placed with an osseointegration rate of 91.49%. Five implants were lost during the osseointegration period (8%). Peri-implant bone resorption was measured with a mean of 1.27 mm. There was no significant difference between the vertical gain technique used and implant survival (p>0.385). Implant survival rates were higher in non-irradiated patients (p<0.017). All patients were rehabilitated with a fixed implant-supported prosthesis reporting a regular diet (80%), normal swallowing (85.7%) and excellent aesthetic results.

Conclusions

Multi-stage implementation of VSP, STL models and cutting guides, CAD/CAM technology, customized plates and in-house dynamic implant navigation for mandibular defects increases bone-to-bone contact, resolves vertical discrepancy and improves operative efficiency with reduced complication rates and minimal bone resorption. It provides accurate reconstruction that optimizes implant placement, thereby improving facial symmetry, aesthetics and function.

Improved procedure for Brown's Class III maxillary reconstruction with composite deep circumflex iliac artery flap using computer-assisted technique

Reconstruction of Brown's Class III maxillary defect can be challenging due to the complex geometry of maxilla. We aimed to introduce an improved method for maxillary reconstruction with a composite deep circumflex iliac artery (DCIA) flap aided by virtual surgical planning and intraoperative navigation. A 27-year-old woman diagnosed with left maxillary fibromyxoma was admitted to our institution in December 2018. Pre-operative facial and iliac computed tomography data were obtained for virtual surgical planning. Personalized cutting template, tooth-supported surgical guide, and rapid prototype model with reconstructed orbital floor were printed for pre-operative preparation. Surgery was completely guided by the intraoperative navigation system. The root mean square estimate of the reconstructed area was 3.68 mm. The average errors measured on the lateral and medial DCIA segments were 0.61 and 0.85 mm, respectively. Application of virtual surgical planning and intraoperative navigation could potentially enhance the reconstruction outcomes.

Vertical Ridge Augmentation of Fibula Flap in Mandibular Reconstruction: A Comparison between Vertical Distraction, Double-Barrel Flap and Iliac Crest Graft

Double-barrel flap, vertical distraction and iliac crest graft are used to reconstruct the vertical height of the fibula. Twenty-four patients with fibula flap were reconstructed comparing these techniques (eight patients in each group) in terms of height of bone, bone resorption, implant success rate and the effects of radiotherapy. The increase in vertical bone with vertical distraction, double-barrel flap and iliac crest was 12.5 ± 0.78 mm, 18.5 ± 0.5 mm, and 17.75 ± 0.6 mm, (p < 0.001). The perimplant bone resorption was 2.31 ± 0.12 mm, 1.23 ± 0.09 mm and 1.43 ± 0.042 mm (p < 0.001), respectively. There were significant differences in vertical bone reconstruction and bone resorption between double-barrel flap and vertical distraction and between iliac crest and vertical distraction (p < 0.001). The study did not show significant differences in implant failure (p = 0.346). Radiotherapy did not affect vertical bone reconstruction (p = 0.125) or bone resorption (p = 0.237) but it showed higher implant failure in radiated patients (p = 0.015). The double-barrel flap and iliac crest graft showed better stability in the height of bone and less bone resorption and higher implant success rates compared with vertical distraction. Radiation therapy did not affect the vertical bone reconstruction but resulted in a higher implant failure.

Application of optimized digital surgical guides in mandibular resection and reconstruction with vascularized fibula flaps: Two case reports

RATIONALE

Currently, digital surgical techniques have been widely used in the precise treatment of mandibular resection and reconstruction with fibula flaps. Utilizing these innovative techniques in surgical planning and hardware fabrication before surgery has shown to provide great help. However, it is difficult for even experienced surgeons to place the preformed reconstruction plate in the same position as its preoperative design, causing surgical results to differ from preoperative planning. This study aims to solve these acknowledged challenges by creating newly designed equipment.

PATIENT CONCERNS

Two patients suffering from long-term expansion of the mandible were admitted to our department. Case I was a 39-year-old female patient who was concerned about the disease in the middle of the mandible, Case II was a 45-year-old female patient who was concerned about the disease at the left mandibular angle and ramus region.

DIAGNOSES

Two patients were diagnosed with the mandibular ameloblastoma based on computed tomography (CT) scan and pathological results.

INTERVENTIONS

Personalized 3-dimensional (3D) surgical guides were applied to 2 patients with mandibular ameloblastoma who underwent mandibular resection and reconstruction with vascularized fibula flaps using a specially optimized and designed reconstruction guide plate.

OUTCOMES

We achieved precise mandibular repair with such a guide in full accordance with the preoperative plan and ensured the restoration of patient facial symmetry.

LESSONS

Optimized reconstruction guide template could accurately locate the preformed reconstruction plate. This component had the ability to ensure that the location of the actual reconstruction plates were highly consistent with preoperative designed models.

Primary Maxillary Reconstruction With Fibula Flap and Dental Implants: A Comparative Study Between Virtual Surgical Planning and Standard Surgery in Class IIC Defects

PURPOSE

Oncological patients who undergo bilateral subtotal maxillectomies develop functional and esthetic sequelae that require immediate reconstruction. The purpose of this study is to evaluate the primary reconstruction of maxillary defects with fibula flap and dental implants assisted by virtual surgical planning (VSP) and to assess the postoperative outcomes compared with standard surgery.

MATERIAL AND METHODS

A retrospective study was designed between January 2016 and April 2020 with 12 oncologic patients who underwent subtotal bilateral maxillectomy. Six consecutive patients were treated by standard surgical procedure (SS) at the beginning of the study. In 2018, the VSP was implemented, and 6 consecutive patients were treated using this technique. All patients were rehabilitated with Ticare implants and implant prostheses. Anatomic position of the bone, bone apposition, change of vertical distance, and horizontal shift, the operative and ischemia time, the esthetic results, and the functional rehabilitation were evaluated and compared.

RESULTS

The position of the bone in anatomical position was 100% in the VSP group vs 66% in the SS group. The bone apposition was 100% in the VSP group vs 83.3%. The change of vertical distance and the horizontal shift were lower in the VSP group (P < .05). The ischemia time and operative time were shorter in the VSP group (P < .05). A good esthetic result was achieved in 83.3% in the VSP group vs 33.3% in the SS group; 81 dental implants and 1 zygomatic implant were placed. The success rate was 95% in the VSP group and 92.6% in the SS group. All patients were rehabilitated with implant prosthesis.

CONCLUSIONS

VSP improves the accuracy of midface reconstruction (class IIC defect) with a better anatomical position of the bone, a higher rate of bone contact, and a lower change in vertical distance compared with standard surgery. It significantly improves the esthetic result, reduces ischemia time, and operation time.

Delayed Reconstruction of Palatomaxillary Defect Using Fibula Free Flap

Introduction. The objective of this study was to evaluate a surgical technique and to present the results of delayed reconstruction of palatomaxillary defects using fibula free flap (FFF). Methods. A review was conducted for nine patients who underwent palatomaxillary reconstruction using FFF. Primary disease, type of reconstruction, defect area, fibula segment length and number of osteotomies, radiotherapy, and implant installation after FFF reconstruction were analyzed. Results. All nine patients underwent delayed reconstruction. The fibula shaft was osteotomized into two segments in seven patients and three segments in one patient with bilateral Brown’s revised classification IV/d defect. One case was planned by using a computer-aided design computer-aided manufacturing (CAD/CAM) system with a navigation system. The mean length of the grafted fibula bone was 68.06 mm. Dental implant treatment was performed in six patients. Six patients received radiation therapy, and there were no specific complications related to the radiation therapy. In one case, the defect was reconstructed with FFF flow-through from a radial forearm free flap. Conclusion. This clinical study demonstrated that the fibula flap is an ideal donor-free flap in a palatomaxillary defect. Delayed reconstruction using an FFF can reduce the complication and failure rates.

Recent advance in patient-specific 3D printing templates in mandibular reconstruction

Patient-specific 3D printing template is used in mandibular defect reconstruction with multiple deficiencies. During the operation, the template can accurately transfer the preoperative design, assisting surgeons to complete the surgery with high efficiency and accuracy. The template design has been continuously improved to obtain good application for miscellaneous classification and description. This review attempted to preliminarily analyse and summarise recent advancements in personalized 3D printing templates in mandibular reconstruction from the aspects of functional classification, existing problems, improved strategies and post-surgery evaluation by reviewing studies and through our combined clinical work and experience on hundreds of reconstruction surgeries.

Mirror Image Based Three-Dimensional Virtual Surgical Planning and Three-Dimensional Printing Guide System for the Reconstruction of Wide Maxilla Defect Using the Deep Circumflex Iliac Artery Free Flap

A patient was diagnosed with squamous cell carcinoma of the maxillary sinus and consequently underwent a unilateral total maxillectomy and reconstruction using an anterolateral thigh (ALT) free flap. Soft tissue transplantation without a bone graft at the large maxillary defect site caused a midfacial collapse, which worsened, especially after radiotherapy. The 3-dimensional positioning of the composite flap for wide maxillary reconstruction is aesthetically important. To achieve ideal symmetry and aesthetics, a mirror image was created using the normal contralateral side. Through computer simulation, the function and symmetry of the virtually reconstructed maxilla was evaluated, and the surgical guide was made using a 3D printing system. Based on the prepared surgical guide, a deep circumflex iliac artery (DCIA) free flap was harvested, and its implementation in the reconstruction ultimately led to satisfactory results. Utilization of mirror image based virtual surgical planning and a 3D printing guide is a significantly effective method for maxilla reconstruction with DCIA flaps.

Virtual Surgical Planning for Successful Second-Stage Mandibular Defect Reconstruction Using Vascularized Iliac Crest Bone Flap: A Valid and Reliable Method

PURPOSE

Second-stage reconstruction of mandibular defects faces problems of anatomic disorder and bone displacement due to tumor resection. As a newer technique, virtual surgical planning (VSP) may help to increase the accuracy and efficiency of the complicated reconstruction. This study aims to evaluate the application of VSP and splint-guided surgery in second-stage mandibular reconstruction using vascularized iliac crest bone flap.

METHODS

Between October 2016 and February 2018, 5 patients (3 men and 2 women) with mandibular defects of duration between 8 months and 8 years underwent VSP-aided secondary reconstruction in the School and Hospital of Stomatology of Wuhan University (Wuhan, China). Virtual surgical planning was performed and serial guiding splints were printed to replicate the design into the actual operation. The linear and 3-dimensional deviations after surgery were analyzed. Patient complications and feedback were recorded during follow up.

RESULTS

All 5 patients underwent successful reconstruction using vascularized iliac crest bone flap. No serious donor sites or recipient site complications were observed after 10- to 28-month follow-up. In comparison with the presurgery designs, the linear deviations in coronal plane were 2.7 ± 0.4 mm (range, -2.2 to 3.9 mm) in measurements from the condylar head to the condylar head and 0.70 ± 0.6 mm (range, -0.1 to 1.7 mm) from the gonial angle to the gonial angle, and that in sagittal plane was 2.4 ± 0.88 mm (range, -3 to 4.4 mm) from the anterior inferior mandibular border to the center point on the condylar head to the condylar head line. The whole 3-dimensional deviation was 1.2 ± 1.7 mm in all patients.

CONCLUSION

Well-designed splints can assist in precise mandibular reconstruction with high efficiency and accuracy, and thus are a reliable method for complicated second-stage mandibular reconstruction. However, to achieve a better outcome, a satisfactory design is required to adapt the complicated and varied defect.

WITHDRAWN: Expanded Transoral Microvascular Mandibular Reconstruction: A Scar-Free Approach

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Novel Patient-Specific 3-Dimensional Printed Fixation Tray for Mandibular Reconstruction With Fibular Free Flaps

Segmental mandibular defects secondary to infectious, traumatic, and pathologic conditions can be debilitating because of their impact on function and facial esthetics. Several reconstructive techniques are available, with vascularized flaps commonly used for the reconstruction of large bony or composite segmental defects. The free fibular flap for mandibular reconstruction is well documented and remains a commonly used flap because of its bone length, versatility, distant location from the head and neck region that allows for a 2-team approach, and ability to simultaneously place endosseous implants. Virtual surgical planning (VSP) and guided resection and reconstruction of maxillofacial defects have facilitated complex 3-dimensional (3D) reconstruction. The accuracy and fidelity of VSP are dependent on the intraoperative execution of the VSP, with computer-aided design and computer-aided modeling of patient-specific cutting guides and hardware providing a template for its execution. The goal of this report is to describe the authors' experience with the use of a novel 3D printed fixation tray designed from the VSP data. It provides dual functionality by aiding in alignment and stabilization of the fibular segments and concomitantly providing patient-specific anatomic references for indexing of bony and soft tissue components. This tray enables rapid ex vivo configuration of the fibula segment(s) with the reconstruction bar relative to the native mandibular segments and allows the compiled construct to be transferred to the head and neck for insetting as a precisely configured single unit.

Computed Tomographic Angiography Perforator Localization for Virtual Surgical Planning of Osteocutaneous Fibular Free Flaps in Head and Neck Reconstruction

Virtual surgical planning (VSP), computer-aided design and computer-aided modeling, and 3-dimensional printing are 3 distinct technologies that have become increasingly employed in head and neck oncology and microvascular reconstruction. Although each of these technologies have long been utilized for treatment planning in other surgical disciplines such as craniofacial surgery, trauma surgery, temporomandibular joint surgery, and orthognathic surgery, its widespread use in head and neck reconstructive surgery remains a much more recent advent. In response to the growing trend of VSP being used for the planning of fibular free flaps in head and neck reconstruction, some surgeons have questioned the technology's implementation based upon its perceived inadequacy in addressing other reconstructive considerations beyond hard tissue anatomy. Detractors of VSP for head and neck reconstruction highlight its lack of capability in accounting for multiple reconstructive factors, such as recipient vessel selection, vascular pedicle reach, need for dead space obliteration, and skin paddle perforator location. It is with this premise in mind that we report a simple technique for anatomically localizing peroneal artery perforators during VSP for osteocutaneous fibular free flaps in which both bone and a soft tissue skin paddle are required for ablative reconstruction. The technique allows for anatomic perforator localization during the VSP session based solely upon data existent within the preoperative computed tomographic angiography (CTA) and it does not require any modifications to preoperative clinical workflows. It is the authors' presumption that many surgeons in the field are unaware of this planning capability within the context of modern VSP for head and neck reconstruction. The primary purpose of this manuscript is to introduce and further familiarize surgeons with the technique of CTA perforator localization as a method of improving intraoperative fidelity for VSP of osteocutaneous fibular free flaps.

Using 3D computer planning for complex reconstruction of mandibular defects

For complex reconstruction of osseous defects of the head and neck, three-dimensional (3D) computer planning has been available for over 20 years. However, despite its availability and recent refinements, it is a technology that has not been widely adopted. While 3D computer planning has been proposed to improve surgical precision, reduce operating time and enhance functional outcomes, the objective evidence supporting these claims is limited. Here we review the recent literature that supports the use of 3D computer planning for complex osseous defects of the mandible. We highlight a case example where 3D modeling played a critical role, particularly during the virtual surgical planning stage. Finally, we propose that routine post-operative 3D analysis become an essential element in determining operative success. Critical evaluation of outcomes will better define its use in complex reconstruction of osseous defects.

Designing patient-specific 3D printed craniofacial implants using a novel topology optimization method

Large craniofacial defects require efficient bone replacements which should not only provide good aesthetics but also possess stable structural function. The proposed work uses a novel multiresolution topology optimization method to achieve the task. Using a compliance minimization objective, patient-specific bone replacement shapes can be designed for different clinical cases that ensure revival of efficient load transfer mechanisms in the mid-face. In this work, four clinical cases are introduced and their respective patient-specific designs are obtained using the proposed method. The optimized designs are then virtually inserted into the defect to visually inspect the viability of the design . Further, once the design is verified by the reconstructive surgeon, prototypes are fabricated using a 3D printer for validation. The robustness of the designs are mechanically tested by subjecting them to a physiological loading condition which mimics the masticatory activity. The full-field strain result through 3D image correlation and the finite element analysis implies that the solution can survive the maximum mastication of 120 lb. Also, the designs have the potential to restore the buttress system and provide the structural integrity. Using the topology optimization framework in designing the bone replacement shapes would deliver surgeons new alternatives for rather complicated mid-face reconstruction.

Combined use of an anterolateral thigh flap and rapid prototype modeling to reconstruct maxillary oncologic resections and midface defects

The most complex area for reconstruction of the head and the neck is the maxilla and the midface because of the difficult anatomy of this region. This article aimed to describe our design for the reconstruction of the zygomaticomaxillary complex using an anterolateral thigh (ALT) flap combined with a rapid prototyping technology. Seven patients were involved in this study. All free ALT flaps survived, and the patients were satisfied with the results both esthetically and functionally 8 months after surgery. The free ALT flap with a titanium mesh made by rapid prototyping technology is a reliable option for the treatment of oncologic resections of the maxilla and other midface defects. This technique has a significantly shorter surgical time than conventional procedures, with good and predictable postoperative outcomes.

Custom facial reconstruction for osteosarcoma of the jaw

Osteosarcoma accounts for most primary bone cancers in children and young adults. High-grade lesions are typically managed with a combination of chemotherapy and wide-margin surgical excision. Although this malignancy typically affects the metaphyseal region of long bones, it also can be seen in the axial skeleton. Of axial locations, tumors in the head and neck can be particularly troubling to treat. Segmental bone loss after resection of malignant mandibular tumors continues to present important challenges to the reconstructive surgeon. Recent advancements in 3-dimensional modeling have facilitated custom templates for patient-specific reconstructions. This report describes the case of a young woman with osteosarcoma of the mandible undergoing customized template composite facial reconstruction using a vascularized osteoseptocutaneous fibula flap.

Experimental validation of 3D printed patient-specific implants using digital image correlation and finite element analysis

With the dawn of 3D printing technology, patient-specific implant designs are set to have a paradigm shift. A topology optimization method in designing patient-specific craniofacial implants has been developed to ensure adequate load transfer mechanism and restore the form and function of the mid-face. Patient-specific finite element models are used to design these implants and to validate whether they are viable for physiological loading such as mastication. Validation of these topology optimized finite element models using mechanical testing is a critical step. Instead of inserting the implants into a cadaver or patient, we embed the implants into the computer-aided skull model of a patient and, fuse them together to 3D print the complete skull model with the implant. Masticatory forces are applied in the molar region to simulate chewing and measure the stress-strain trajectory. Until recently, strain gages have been used to measure strains for validation. Digital Image Correlation (DIC) method is a relatively new technique for full-field strain measurement which provides a continuous deformation field data. The main objective of this study is to validate the finite element model of patient-specific craniofacial implants against the strain data from the DIC obtained during the mastication simulation and show that the optimized shapes provide adequate load-transfer mechanism. Patient-specific models are obtained from CT scans. The principal maximum and minimum strains are compared. The computational and experimental approach to designing patient-specific implants proved to be a viable technique for mid-face craniofacial reconstruction.

Advances in oncologic head and neck reconstruction: systematic review and future considerations of virtual surgical planning and computer aided design/computer aided modeling

BACKGROUND

Mastery of craniomaxillofacial reconstruction has been traditionally considered to be learning curve dependent, often with inconsistent results during the skill acquisition phase. Until recently, the overall success in bony oncologic reconstruction of the craniomaxillofacial skeleton has relied mainly on the use of 2D imaging modalities, as well as surgical trial-and-error. Virtual surgical planning (VSP) and computer aided design (CAD)/computer aided modeling (CAM) are gaining traction in oncologic applications and offers opportunity for increased accuracy, improved efficiency, and enhanced outcomes. Its role in oncologic head and neck reconstruction has not been formally evaluated.

METHODS

A systematic review of the current literature was conducted by three independent reviewers. Three separate search schemes were utilized to identify cases incorporating VSP-CAD/CAM technology in head and neck reconstruction for an oncologic indication. Inclusion and exclusion criteria were applied; articles that met criteria were evaluated for cohort demographics, osteocutaneous flap type and usage, oncologic indication, recipient bone reconstructed, flap survival, follow up, VSP technology usage, specific reported benefits of the technology, and qualitative and quantitative outcome assessments.

RESULTS

The systematic literature review yielded 87 articles; of these, 33 met inclusion criteria describing a total of 220 cases of oncologic head and neck reconstruction incorporating virtual planning technology. Numerous qualitative benefits of VSP were reported including increased accuracy of the reconstruction (93%), decreased intraoperative time (80%), and ease of use (24%) among others. However, quantitative results using survey data or preoperative/postoperative CT scan comparisons were given for only 33% (3%, 30% respectively) of cases.

CONCLUSION

VSP represents an evolving technology that ushers oncological craniomaxillofacial reconstruction into a modern era that holds potential to advance the field with increased reconstructive accuracy, expedition of the surgical phase, and improved outcomes. While qualitative improvements from the technology are delineated, specific quantifiable benefits and cost-benefit analysis are limited and need to be further investigated.