Donor site morbidity after computer assisted surgical reconstruction of the mandible using deep circumflex iliac artery grafts: a cross sectional study.

BACKGROUND: Computer Assisted Design and Computer Assisted Manufacturing (CAD/CAM) have revolutionized oncologic surgery of the head and neck. A multitude of benefits of this technique has been described, but there are only few reports of donor site comorbidity following CAD/CAM surgery. METHODS: This study investigated comorbidity of the hip following deep circumflex iliac artery (DCIA) graft raising using CAD/CAM techniques. A cross-sectional examination was performed to determine range of motion, muscle strength and nerve disturbances. Furthermore, correlations between graft volume and skin incision length with postoperative donor site morbidity were assessed using Spearman's rank correlation, linear regression and analysis of variance (ANOVA). RESULTS: Fifteen patients with a mean graft volume of 21.2 ± 5.7 cm3 and a mean incision length of 228.0 ± 30.0 mm were included. Patients reported of noticeable physical limitations in daily life activities (12.3 ± 11.9 weeks) and athletic activities (38.4 ± 40.0 weeks in mean) following surgery. Graft volume significantly correlated with the duration of the use of walking aids (R = 0.57; p = 0.033) and impairment in daily life activities (R = 0.65; p = 0.012). The length of the scar of the donor-site showed a statistically significant association with postoperative iliohypogastric nerve deficits (F = 4.4, p = 0.037). Patients with anaesthaesia of a peripheral cutaneous nerve had a larger mean scar length (280 ± 30.0 mm) than subjects with hypaesthesia (245 ± 10.1 mm) or no complaints (216 ± 27.7 mm). CONCLUSIONS: Despite sophisticated planning options in modern CAD/CAM surgery, comorbidity of the donor site following  iliac graft harvesting is still a problem. This study is the first to investigate comorbidity after DCIA graft raising in a patient group treated exclusively with CAD/CAM techniques. The results indicate that a minimal invasive approach in terms of small graft volumes and small skin incisions could help to reduce postoperative symptomatology. Trial registration Retrospectively registered at the German Clinical Trials Register (DRKS-ID: DRKS00029066); registration date: 23/05/2022.

Three-dimensional printed titanium mesh combined with iliac cancellous bone in the reconstruction of mandibular defects secondary to ameloblastoma resection.

BACKGROUND: The reconstruction of large mandibular defects is a challenge, and free vascularized bone flaps are most commonly used. However, the precision and symmetry of this repair are deficient, and patients have a risk of vascular embolism, flap necrosis, and donor site complications. Therefore, to explore an ideal alternative in mandibular reconstruction with high surgical accuracy and low complications is indispensable. METHODS: Seven patients with recurrent or large-scope ameloblastoma were enrolled in this study. All patients were provided with a fully digital treatment plan, including the design of osteotomy lines, surgical guides, and three-dimensional printed titanium mesh for implantation. With the assistance of surgical guide, ameloblastomas were resected, and custom 3D printed titanium mesh combined with posterior iliac bone harvest was used in mandibular reconstruction. A comparison was made between the discrepant surgical outcomes and the intended surgical plan, as well as the average three-dimensional deviation of the mandible before and after the surgery. At the same time, the resorption rate of the implanted bone was evaluated. RESULTS: All patients completed the fully digital treatment process successfully without severe complications. Image fusion showed that the postoperative contour of the mandible was basically consistent with surgical planning, except for a slight increase in the inferior border of the affected side. The mean three-dimensional deviation of the mandible between the preoperative and postoperative periods was 0.78 ± 0.41 mm. The mean error between the intraoperative bone volume and the digital planning bone volume was 2.44%±2.10%. Furthermore, the bone resorption rates of the harvested graft 6 months later were 32.15%±6.95%. CONCLUSIONS: The use of digital surgical planning and 3D-printed templates can assist surgeons in performing surgery precisely, and the 3D-printed titanium mesh implant can improve the patient's facial symmetry. 3D printed titanium mesh combined with posterior iliac cancellous bone graft can be regarded as an ideal alternative in extensive mandibular reconstruction.

Masticatory performance in patients undergoing free fibula flap for mandible reconstruction.

BACKGROUND: To explore the masticatory performance in patients undergoing an osteo(cutaneous) free fibula (OFF) flap for mandible reconstruction by a prospective design. METHODS: A total of 56 patients who had undergone OFF flap reconstructions for mandibular reconstruction secondary to malignant (squamous cell carcinoma) or benign (ameloblastoma) tumor resection were prospectively enrolled. They were asked to complete the masticatory performance test by the weigh method and the chew domain of the University of Washington quality of life questionnaire (version 4) preoperatively and at 3, 6, and 12 months postoperatively. The pair nonparametric test was used to analyze the dynamic change of masticatory performance and subjective chew function. RESULTS: Fifty-one patients were included for analysis finally. The mean masticatory performance for patients with malignant tumors were 53.4% ± 10.3%, 36.4% ± 10.3%, 42.6% ± 9.6%, 52.8% ± 10.9%, and 53.1% ± 11.8% preoperatively, at 2 weeks, 3 months, 6 months, and 12 months postoperatively, respectively. Compared with the preoperative level, the masticatory performance had a significant reduction immediately after surgery (p < 0.001), followed by a return to the baseline level within three months. A similar trend was noted for those with benign tumors. The mean score of chew domain for patients with malignant tumors were 100 ± 0, 54.3 ± 32.9, 81.4 ± 24.5, and 92.9 ± 17.8 preoperatively, at 3 months, 6 months, and 12 months postoperatively, respectively. Compared with the preoperative level, the subjective chew function was greatly affected within the first three months (p < 0.001), and it gradually recovered to the baseline level in the following nine months. A similar trend was noted in patients with benign tumors. CONCLUSIONS: The masticatory performance and subjective chew function was significantly affected after OFF flap reconstructions in the short term, but both recovered to the preoperative levels within 9-12 months.

TOTAL MANDIBULAR DEFECT RECONSTRUCTION BY TOTAL TITANIUM PATIENT-SPECIFIC IMPLANT: CLINICAL EFFICACY AND LONG TERM FOLLOW UP. CLINICAL CASE.

The aim of this clinical case in demonstrating the possibility of replacing total defect of the mandible with a patient specific implant and the result of long-term follow up. Literature data on the replacement of total mandibular defects are extremely limited and they are presented by only several clinical cases where various surgical approaches were used. In the available literature, there are two approaches to solving this problem, including the replacement of the jaw with vascularised bone grafts, of which the fibula flap is the most promising, and the implantation of endoprostheses of the jaws, of which patient-specific anatomical endoprostheses made using additive technologies are the most advanced. The concept of using patient-specific endoprostheses of the whole mandible is considered revolutionary because it has a number of significant benefits, including the greatest accuracy in restoring the anatomical shape of the mandible. One of the unresolved problems associated with the installation of total mandibular endoprostheses is the prosthetic rehabilitation of patients using fixed structures. The analysis of the presented case can be a good tool for the clinician and bioengineer while making the final decision on the treatment method and modality in patients who need an identical option for the repair of a mandibular defect. Based on CT data, we can conclude that the employed approach, methodology of design and manufacture of patient-specific titanium mandibular endoprosthesis for the total defect demonstrated the sufficient efficacy, which suggest the need for further systematic studies to address this issue.

Development of a template tool for facilitating fibula osteotomy in reconstruction of mandibular defects by digital analysis of the human mandible.

OBJECTIVES: Mandibular reconstruction after segmental mandibulectomy can be challenging without virtual surgical planning and osteotomy guides. The purpose of this study was to analyze anatomic parameters to facilitate the evaluation of ideal fibula wedge osteotomies to reconstruct the neomandibula in a simple and cost-effective manner without the need for preoperative virtual planning. MATERIALS AND METHODS: Computed tomography scans were acquired from randomly selected patients, and all images were obtained from routine clinical diagnostics, e.g., tumor staging, or preoperatively before reconstruction. Data was used to calculate stereolithographic models of the mandible for length and angle measurements. Statistical analysis was performed (p < 0.05). RESULTS: CT scans of 100 patients were analyzed: 39 were female and 61 were male patients, mean age was 59.08a. The mandibular arch angle proved to be constant with 241.07 ± 2.39°. The outside B-segment length was 80.05 ± 5.16 mm; the anterior S-segment length was 27.69 ± 3.16 mm. The angle of the mandibular arch showed differences in means (p = 0.004) between age groups, but effect was proved low. No relevant statistical significances were detected. CONCLUSIONS: The development of a mandible reconstruction template tool would benefit the majority of head and neck patients, which is due to a constant mandibular arch angle and symphysis segment length throughout the general patient population, allowing the mimicking of a harmonic mandibular arch with up to three fibula segments. CLINICAL RELEVANCE: The developed mandible reconstruction template tool can facilitate the fibula wedge osteotomies necessary for reconstruction of an ideal neomandibula providing a novel approach which is simple and cost-effective.

[Evolution of the mandibular defects reconstruction with free fibula flapx]. / Évoliutsiia v planirovanii i modelirovanii revaskuliarizuemogo malobertsovogo autotransplantata pri ustranenii defektov nizhnei cheliusti.

One of the most important steps in achieving aesthetical and functional result in mandible reconstruction with fibula free flap is positioning of the bony part relative to the basis of the native mandible. Positioning fibular bony part continuing inferior mandible border may produce a high discrepancy between the residual mandible and fibula bone that results in difficulty in denture rehabilitation. Positioning fibular bony part continuing alveolar mandible border creates asymmetric jowls and changed shape of jawline in border-line zone. The double-barrel technique solves this problem, but needs a meticulous preoperative planning and precision free fibula flap modelling.

Minimizing osteoradionecrosis after mandibular reconstruction and radiation in advanced head and neck cancer patients.

BACKGROUND: Osteoradionecrosis may develop on the residual mandible or reconstructed fibula because of inadequate soft tissue coverage and compromised tissue perfusion post mandibular reconstruction, and radiation. This study was to investigate the incidence of osteoradionecrosis following class III mandibular defect reconstructions with an OPAC flap versus a fibula OSC flap. METHODS: A retrospective review of a consecutive series of mandibular reconstructions between 1999 and 2010 was performed. Mandibular defects and corresponding flap types were analyzed with emphasis on outcome, complications, and rates of osteoradionecrosis among the two subgroups. RESULTS: A total of 121 fibula flaps were performed, consisting of 53 OPAC and 68 fibula OSC flaps. Complications trended higher for OPAC flaps in partial and total flap loss rates as well as venous congestion when compared with the OSC flap cohort. The OPAC group had statistically significant lower rates of osteoradionecrosis and plate exposure than the OSC group (P = 0.04). CONCLUSION: The OPAC flap may be preferable to fibula OSC flap in mandibular reconstruction given its lower rates of osteoradionecrosis and plate exposure. This flap type may be the flap of choice for class III defects where additional vascularized tissue may be critical for addressing significant soft tissue deficiency. J. Surg. Oncol. 2016;114:399-404. © 2016 Wiley Periodicals, Inc.

Regions of ilium and fibula providing clinically usable bone for mandible reconstruction: "A different approach to bone comparison".

A variety of donor sites are available for mandibular reconstruction. We present here a different way of comparing two commonly-used bone flaps. The lengths of the usable parts in a total of 241 coxal bones, 91 mandibles and 60 fibulas were measured. The mandible was measured from condyle-to-condyle and the harvestable bone length (HBL) and usable (UBL) bone lengths in fibula and ilium were also measured. The bone thickness (BT) in 60 iliac crests was measured in two parallel lines from the anterior superior iliac spine (ASIS) along the iliac crest. The mandible was 32.17 mm shorter in females than in males. The total ilium UBL was 171.12 mm in females and 178.80 mm in males. The mean HBL of the fibula was 22.6 mm shorter in females than in males. However, in some fibulas in both females and males, only 4.2% and 21.1% of the HBL respectively could be used if the ultimate goal was to insert dental implants. We found significant correlations between BT and gender in both fibula and ilium (P≤ 0.05). The ilium offers constant BT throughout the usable bone area with a similar bone length to the fibula. In contrast, the fibula showed variable bone dimensions, so not all of it is clinically usable. This should especially be considered in females when a mandibular reconstruction is planned with the goal of occlusal rehabilitation. Clin. Anat. 29:773-778, 2016. © 2016 Wiley Periodicals, Inc.

A Novel Method for Secondary Mandible Reconstruction to Re-Achieve a Native Condyle Position Comprising a New Design for Cutting Guides and New Positioning Devices.

Secondary mandibular reconstruction using fibular free flaps (FFF) is a technical challenge for surgeons. Appropriate operation planning is crucial for postoperative quality control and is notably necessary for the (re-) achievement of a physiological condylar position, and the sensible expansion and shaping of the transplant. Computer-assisted planning may help to reconstruct mandibular defects in a patient-specific and precise manner. Herein, we present a newly-developed workflow for secondary mandibular reconstruction using FFF; it comprises digital planning and in-house manufacturing to perform precise secondary mandible reconstruction. This method utilizes a newly designed positioning device to ensure the precise positioning of the fibula segments in relation to each other and the mandibular stumps. The presented in-house-printed positioning device made it possible to achieve digital planning with high precision during surgery.

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.

Influence of microvascular mandibular bony reconstruction on the posterior airway space: A retrospective cohort study.

INTRODUCTION: The posterior airway space (PAS) is a common site of passive obstructions with high morbidity. Surgical changes to the craniomandibular system may affect the PAS. Data regarding the effects of mandibular reconstruction using vascularized bone flaps on PAS are insufficient. This retrospective cohort study aimed to investigate changes in PAS after mandibular reconstruction. MATERIALS AND METHODS: Pre- and post-reconstructive computed tomography scans of 40 patients undergoing segmental mandibulectomy and mandibular reconstruction with deep circumflex iliac artery or fibula flaps were analyzed. Absolute differences in PAS geometry and relative trends of PAS volume changes were compared within the study population and between subgroups formed according to the extent of resection, timing and type of reconstruction, and presence of pre-reconstructive radiotherapy. RESULTS: Irradiated patients were characterized by an increase in PAS volume after reconstruction. Absolute differences in total PAS volume after reconstruction were significantly different (p = 0.024) compared to non-irradiated patients. Reconstruction of central mandible segments resulted in decrease of the cross-sectional PAS areas. Absolute differences in middle cross-sectional PAS area after reconstruction were significantly different (p = 0.039) compared to non-central reconstructions. Patients who received radiotherapy were less likely to show a total PAS volume reduction after reconstruction (OR: 0.147; p = 0.007), with values adjusted for gender, age, body mass index, timing and type of reconstruction, and transplant length. CONCLUSIONS: Mandibular reconstruction causes changes in PAS geometry. Specifically, reconstructions of central mandibular segments can lead to a reduction in the cross-sectional areas of PAS, and mandibular reconstructions in irradiated sites may cause an increase in PAS volume.

Use of reconstruction plates prebent on three-dimensional models to reduce the complications of mandibular reconstruction.

Background/purpose: Though the gold standard method for mandible reconstruction of the defect from segmental mandibulectomy is by osseous flap or graft, using reconstruction plates is still indicated in some cases. Traditionally, the plate is bended immediately after the segmental mandibulectomy by freehand. However, it's difficult to fit well to the original position of mandible, which may result in more complications. This study therefore aimed to investigate whether using prebent plates on computer-aided 3D printing models could reduce the complication rate. Materials and methods: Patients who received mandible reconstruction by reconstruction plate from 2018 to 2022 were enrolled and evaluated in this study. The data, including demographics, indications for surgery, pre-existed preoperative and postoperative therapies, classification of defects, and postoperative outcomes were collected and analyzed. Results: A total of 52 patients were enrolled in our study. The prebent group exhibited a significantly lower complication rate than that of the immediately bent group (P = 0.012). Other risk factors of plate complications included postoperative adjuvant radiotherapy (P = 0.017) and previous surgery (P = 0.047). The complication-free survival rate was also better in the prebent group in a 3-year follow-up period (P = 0.012). Conclusion: Prebent plates on computer-aided printing models proved to be an effective approach to reduce the complications for mandibular reconstruction in segmental mandibulectomy.

Soft-tissue, non-osteogenic distraction of the mandible and lower face in bilateral hemifacial microsomia-technical report.

The aim of this study is to present a sequential strategy of soft-tissue, non-osteogenic distraction with a novel device, followed by microvascular bony reconstruction for severe cases of mandibular hypoplasia. The case of a 21-year-old woman with Goldenhar syndrome is presented, whose mandible remained severely hypoplastic despite previous attempts at distraction and was not suitable for further osteogenic distraction. Soft tissue deficiency and pin track scarring prevented free fibular transfers. A personalized distractor, anchored to the cranium and the mandibular symphysis, was designed to expand the soft tissues while allowing for physiological temporomandibular joint (TMJ) movement without compression forces. Internal distractors were placed along the osteotomies to prevent condylar luxation. After completion of the soft tissue distraction, the native mandible was resected except for the condyles and reconstructed with two free fibula flaps. This report represents the proof of concept of a sequential approach to severe lower face soft-tissue and bone deficiency, which preserves TMJ function and avoids the transfer of poorly matched skin to the face.

The Reconstruction of Mandible Defects in War Injuries: Systematic Review and Meta-Analysis.

Study Design: Systematic Review and Meta-Analysis. Objective: There has been an increasing trend in maxillofacial injuries associated with combat trauma. Within the maxillofacial complex, the mandible is the most likely structure to be damaged during combat. The structural deficits as a result can be reconstructed with many options. These include vascularised bone grafts (VBGs), non-vascularised bone grafts (NVBGs), alloplastic implants, reconstruction bars and distraction osteogenesis. This study aimed to determine the common modality and efficacy of mandibular reconstruction in combat trauma-related defects. Methods: A literature search was conducted on Pubmed, Prospero, Dynamed, DARE, EMBASE, COCHRANE and BMJ databases. Results: A total of six articles met the inclusion criteria identifying 165 patients requiring mandibular reconstruction. Non-vascularised iliac bone graft (n = 137) was the most common method followed by ileac crest bone chips harvest using Dacron urethran osteomesh tray (n = 24) and frontoparietal grafts (n = 4). Meta-analysis of five out of six trials demonstrated an overall success rate of 85% (95% CI 79-90; I2 = 59%). A total of 13% (n = 22) of reconstructions failed either completely or partially and 21% (n = 34) of patients suffered postoperative complications. Conclusions: NVBGs are a practical, cost-effective and favourable method of war zone management of mandibular defects with success rates comparable to those reported in the civilian literature. However, general trauma principles take precedence to rule out life-threatening injuries. Due consideration of patient factors, surgical factors, and available resources are required in the first-line management of combat-related mandibular defects.

Personalized lattice-structured prosthesis as a graftless solution for mandible reconstruction and prosthetic restoration: A finite element analysis.

Oral cavity tumors are a prevalent cause of mandible reconstruction surgeries. The mandible is vital for functions like oralization, respiration, mastication, and deglutition. Current mandible reconstruction methods have low success rates due to complications like plate fracture or exposure, infections, and screw loosening. Autogenous bone grafts are commonly used but carry the risk of donor region morbidity. Despite technological advances, an ideal solution for mandible reconstruction remains elusive. Additive manufacturing in medicine offers personalized prosthetics from patient-specific medical images, allowing for the creation of porous structures with tailored mechanical properties that mimic bone properties. This study compared a commercial reconstruction plate with a lattice-structured personalized prosthesis under different biting and osseointegration conditions using Finite Element Analysis. Patient-specific images were obtained from an individual who underwent mandible reconstruction with a commercial plate and suffered from plate fracture by fatigue after 26 months. Compared to the commercial plate, the maximum von Mises equivalent stress was significantly lowered for the personalized prosthesis, hindering a possible fatigue fracture. The equivalent von Mises strains found in bone were within bone maintenance and remodeling intervals. This work introduces a design that doesn't require grafts for large bone defects and allows for dental prosthesis addition without the need for implants.

Straight-segment mandibulectomy: a reproducible porcine mandibular critical-size defect model.

Porcine mandibular defect models are commonly used for the preclinical evaluation of reconstruction techniques. Existing studies vary in technique, complexity, and postoperative outcomes. The procedures are complex and often described without sufficient detail. We describe in detail a simple and reproducible method for creating a critical-size mandibular defect in a porcine model. Seven hemimandibular critical size defects were created in five male Yorkshire-Landrace pigs, three with unilateral defects and two with bilateral defects. A transverse incision was made over the mandibular body. Periosteum was incised and elevated to expose the mandibular body and a critical-size defect of 30 × 20 mm created using an oscillating saw. The implant was inserted and fixed with a titanium reconstruction plate and bicortical locking screws, and the wound closed in layers with resorbable sutures. Intraoral contamination was avoided. Dentition was retained and the mental nerve and its branches preserved. The marginal mandibular nerve was not encountered during dissection. All pigs retained normal masticatory function, and there were no cases of infection, wound breakdown, haematoma, salivary leak, or implant-related complications. The procedure can be performed bilaterally on both hemimandibles without affecting load-bearing function. All pigs survived until the end point of three months. Postoperative computed tomographic scans and histology showed new bone formation, and a three-point bend test showed the restoration of biomechanical strength. Straight-segment mandibulectomy is a simple and reproducible method for the creation of critical-size mandibular defects in a porcine model, simulating a load-bearing situation.

Reconstruction of the mandible from partial inputs for virtual surgery planning.

Statistical Shape Models (SSMs) and Sparse Prediction Models (SPMs) based on regressions between cephalometric measurements were compared against standard practice in virtual surgery planning for reconstruction of mandibular defects. Emphasis was placed on the ability of the models to reproduce clinically relevant metrics. CT scans of 50 men and 50 women were collected and split into training and testing datasets according to an 80:20 ratio. The scans were segmented, and anatomical landmarks were identified. SPMs were constructed based on direct regressions between measurements derived from the anatomical landmarks. SSMs were developed by establishing correspondence between the segmented meshes, performing alignment, and principal component analysis. Anterior and bilateral defects were simulated by removing sections of the mandibles in the testing set. Measurement errors after reconstruction ranged from 1.07˚ to 2.2˚ and 0.66 mm to 2.02 mm for mirroring, from 0.45˚ to 3.67˚ and 0.66 mm to 2.54 mm for the SSMs, and from 1.74˚ to 5.01˚ and 0.64 mm to 2.89 mm for the SPMs. Surface-to-surface errors ranged from 1.01 mm to 1.29 mm and 1.06 mm to 1.33 mm for mirroring and SSMs, respectively. Based on the results, SSMs are recommended for VSP in the absence of normal patient anatomy.

Augmented reality guided in reconstruction of mandibular defect with fibular flap: A cadaver study.

BACKGROUND: Augmented reality (AR) navigation has been developed in recent years and can overcome some limitations of existing technologies. This study aimed to investigate a novel method of fibula free flap (FFF) osteotomy based on AR technology through a cadaver study. METHODS: One mandible, seven fibulas, and seven lower limb specimens underwent computed tomography (CT) examination. We used the professional software Proplan CMF 3.0 to design a defective mandible model and created fourteen virtual reconstruction plans using the fibulas and lower limb specimens. The AR-based intraoperative guidance software prototype was developed using the Unity Real-Time Development Platform, and virtual plans were transferred into this software prototype. We used AR-based surgical navigation to guide the FFF osteotomy and used these fibular segments to reconstruct the defective mandible model. After reconstruction, all segments were scanned by CT. Osteotomy accuracy was evaluated by measuring the length and angular deviation between the virtual plan and the final result. The reconstruction precision was reflected by the volume overlap rate and average surface distance between the planned and obtained reconstruction. RESULTS: The length difference, angular deviation, volume overlap rate and average surface distance of the in vitro group were 1.03±0.68 mm, 5.04±2.61°, 95.35±1.81%, and 1.02±0.27 mm, respectively. Those of the in vivo group were 1.18±0.84 mm, 5.45±1.47°, 95.31±2.09%, and 1.22±0.12 mm. CONCLUSIONS: Due to the ideal result of cadaver experiments, an AR-based FFF osteotomy guided system may become a novel approach to assist FFF osteotomy for the reconstruction of defective mandibles.