CAD/CAM guided secondary mandibular reconstruction of a discontinuity defect after ablative cancer surgery

Accuracy of artificial intelligence-based segmentation in maxillofacial structures: a systematic review

OBJECTIVE

The aim of this review was to evaluate the accuracy of artificial intelligence (AI) in the segmentation of teeth, jawbone (maxilla, mandible with temporomandibular joint), and mandibular (inferior alveolar) canal in CBCT and CT scans.

MATERIALS AND METHODS

Articles were retrieved from MEDLINE, Cochrane CENTRAL, IEEE Xplore, and Google Scholar. Eligible studies were analyzed thematically, and their quality was appraised using the JBI checklist for diagnostic test accuracy studies. Meta-analysis was conducted for key performance metrics, including Dice Similarity Coefficient (DSC) and Average Surface Distance (ASD).

RESULTS

A total of 767 non-duplicate articles were identified, and 30 studies were included in the review. Of these, 27 employed deep-learning models, while 3 utilized classical machine-learning approaches. The pooled DSC for mandible segmentation was 0.94 (95% CI: 0.91-0.98), mandibular canal segmentation was 0.694 (95% CI: 0.551-0.838), maxilla segmentation was 0.907 (95% CI: 0.867-0.948), and teeth segmentation was 0.925 (95% CI: 0.891-0.959). Pooled ASD values were 0.534 mm (95% CI: 0.366-0.703) for the mandibular canal, 0.468 mm (95% CI: 0.295-0.641) for the maxilla, and 0.189 mm (95% CI: 0.043-0.335) for teeth. Other metrics, such as sensitivity and precision, were variably reported, with sensitivity exceeding 90% across studies.

CONCLUSION

AI-based segmentation, particularly using deep-learning models, demonstrates high accuracy in the segmentation of dental and maxillofacial structures, comparable to expert manual segmentation. The integration of AI into clinical workflows offers not only accuracy but also substantial time savings, positioning it as a promising tool for automated dental imaging.

The fibula osteoseptocutaneous flap: evolution in concepts, techniques, and technologies during mandibular reconstruction - a review

The fibula-free flap has evolved from its initial description to be a reliable workhorse-free flap providing bone, soft tissue, and a reliable skin paddle. The senior author has been refining this technique since the mid-1980s and has personally performed over 950 hundred cases of the fibula-free flap. The following paragraphs detail an evolution in surgical concepts related to this technique's refinement and serves as a roadmap detailing contemporary mandibular reconstruction.

Segmental resection with primary reconstruction using patient- specific implant for odontogenic fibromyxoma: An illustrative rare case from Nepal

INTRODUCTION

Odontogenic fibromyxoma (OFM) is a round and locally invasive neoplasm predominantly seen in the mandible. Though radiographic appearance is variable, definitive diagnosis is based on correlation with histopathological examination. Surgical approach is the treatment of choice. For reconstruction, patient-specific implant (PSI) has lately been developed as a crucial help.

CASE PRESENTATION

This case report presents a 19 year old female patient with odontogenic fibromyxoma highlighting its clinical, radiographic, histopathological features along with rehabilitation using patient specific implants reducing the complexity and related morbidities of reconstructive procedures.

DISCUSSION

Surgical repair and reconstruction of defects in cranio-maxillofacial region is challenging. The described treatment eliminates the need for bone grafting, shows optimal results owing to the shorter rehabilitation time and more accurate fits.

CONCLUSION

This report introduces a novel technique whereby patient-specific implants are employed as the primary method of reconstruction following segmental resection.

The role of patient specific implants in the oral and maxillofacial region

Reconstructing maxillofacial defects is quiet challenging due to the region's complex anatomy, and cosmetic and functional effects on patients. With the help of developing technologies, patient-specific implants (PSIs) using virtual surgical planning based on a Computer aided designing (CAD)/Computer aided manufacturing (CAM) platform is an evolving treatment option. PSIs can be used in patients with maxillofacial defects and reconstruction. PSIs are also being used in the form of preformed plates for virtually planned orthognathic surgeries. Customized temporomandibular joint (TMJ) prosthesis is being routinely used in the debilitating/degenerative joint disease as a part of alloplastic joint replacement. The reconstruction of the maxillofacial region using autogenous tissue will always be gold standard due to near match of the recipient site. However, autogenous bone grafts positioned using PSIs or in certain areas such as the TMJ complex and the orbital region the PSIs are being offered with advantage of reduced donor-site morbidity. The future research is focussed towards the development of PSIs being used as a scaffold for engineering of the recipient tissue to restore the lost anatomy of specific region. This article reviews the varied aspects of this new technology of PSI for correction of various deformities/defects during the maxillofacial reconstruction.

Comparison of condylar position after free fibular flap mandibular reconstruction using computer-assisted and traditional techniques

OBJECTIVES

To compare the changes in condylar position after mandibular reconstruction with free fibular flap(FFF) and the differences between computer-assisted techniques and traditional methods on CT images.

METHODS

Thirty-four patients who underwent mandibular reconstruction with free fibular flap were selected according to the inclusion and exclusion criteria. In the 3D group, virtual surgical planning (VSP) with osteotomy cutting plate and placement guiding plate were used, while the traditional group underwent freehand reconstruction. The CT data of 68 temporomandibular joints (TMJs) were recorded before and immediately after surgery. The condylar position was evaluated by measuring the anterior space (AS), posterior space (PS) and superior space (SS), and the ln (PS/AS) was calculated according to the method proposed by Pullinger and Hollender.

RESULTS

In the patients included in the 3D group, the condyle on the ipsilateral side moved slightly backward; however, in the patients in the traditional group, the ipsilateral side moved considerably anteroinferior. No obvious changes on the contralateral side were noted. In the 3D group, 33% of ipsilateral condyles were in the posterior position postoperatively when compared with the preoperative position (13%). In the traditional group, the number of ipsilateral condyles in the anterior position increased from 4 to 10, accounting for 53% postoperatively. Contrary to the traditional group, the 3D group presented less condylar displacement on the ipsilateral side postoperatively.

CONCLUSIONS

This study showed a decreased percentage of change in condylar position postoperatively when VSP was used. Virtual surgical planning improved the accuracy of FFF mandibular reconstruction and made the condylar position more stable.

Functional and esthetic outcomes of virtual surgical planning versus the conventional technique in mandibular reconstruction with a free fibula flap: A retrospective study of 24 cases

This study aimed to compare the functional and esthetic results in patients following mandibular reconstruction with a free fibula flap (FFF) by virtual surgical planning (VSP) versus the conventional technique. Patients who had undergone mandibular reconstruction with a FFF by VSP or the conventional technique were retrospectively assessed. The two groups were compared regarding functional and esthetic variables with appropriate scales preoperatively, intraoperatively, and postoperatively. Twenty-four patients were evaluated in two groups: conventional (n = 8) and VSP (n = 16). The mean amount of mandibular asymmetry was 2.62 mm (SD = 1.59) in the conventional group and 1.19 mm (SD = 1.32) in the VSP group. Of the patients who underwent conventional surgery, 12.5% had mandibular asymmetry of <2 mm and 87.5% had asymmetry of 2-5 mm. Of the VSP patients, 61.5% had mandibular asymmetry of <2 mm and 38.5% had mandibular asymmetry of 2-5 mm (p = 0.03). The mean difference in size of mandibular angle on the surgical and control sides was not significantly different between the two groups (p = 0.62). The difference in mean length of the mandibular body on the surgical side relative to the control side was not significant between the two groups (p = 0.75). Differences in functional variables between the two groups were not significant. Within the limitation of the study, it seems that the VSP technique resulted in better facial symmetry and superior esthetic outcomes compared with the conventional technique.

Miniplate Versus Reconstruction Bar Fixation for Oncologic Mandibular Reconstruction with Free Fibula Flaps

BACKGROUND

 Fibula free flaps (FFF) are the gold standard tissue for the reconstruction of segmental mandibular defects. A comparison of miniplate (MP) and reconstruction bar (RB)-based fixation of FFFs has been previously described in a systematic review; however, long-term, single-center studies comparing the two plating methods are lacking. The authors aim to examine the complication profile between MPs and RBs at a single tertiary cancer center. We hypothesized that increased components and a lack of rigid fixation inherent to MPs would lead to higher rates of hardware exposure/failure.

METHODS

 A retrospective review was performed from a prospectively maintained database at Memorial Sloan Kettering Cancer Center. All patients who underwent FFF-based reconstruction of mandibular defects between 2015 and 2021 were included. Data on patient demographics, medical risk factors, operative indications, and chemoradiation were collected. The primary outcomes of interest were perioperative flap-related complications, long-term union rates, osteoradionecrosis (ORN), return to the operating room (OR), and hardware exposure/failure. Recipient site complications were further stratified into two groups: early (<90 days) and late (>90 days).

RESULTS

 In total, 96 patients met the inclusion criteria (RB = 63, MP = 33). Patients in both groups were similar with respect to age, presence of comorbidities, smoking history, and operative characteristics. The mean follow-up period was 17.24 months. In total, 60.6 and 54.0% of patients in the MP and RB cohorts received adjuvant radiation, respectively. There were no differences in rates of hardware failure overall; however, in patients with an initial complication after 90 days, MPs had significantly higher rates of hardware exposure (3 vs. 0, p = 0.046).

CONCLUSION

 MPs were found to have a higher risk of exposed hardware in patients with a late initial recipient site complication. It is possible that improved fixation with highly adaptive RBs designed by computer-aided design/manufacturing technology explains these results. Future studies are needed to assess the effects of rigid mandibular fixation on patient-reported outcome measures in this unique population.

CAD/CAM-assisted ablative surgery and intraoperative brachytherapy for pediatric skull-base sarcomas

BACKGROUND

Head and neck (H&N) sarcomas in children can poise numerous challenges to the surgical oncologist and require multidisciplinary input and meticulous surgical planning. The application of computer-assisted design/computer-assisted manufacturing (CAD/CAM) has been extensively examined in H&N reconstruction in adults, but its utility in ablative oncologic surgery in children warrants further examination. We present preliminary results utilizing CAD/CAM techniques to assist in planning tumor resections and the application of intra-operative radiation in children with skull-base sarcomas.

METHODS

A retrospective cohort review of all pediatric patients who presented to a tertiary care cancer center for surgical resection of a skull-base malignancy was performed between 1980 and 2021. All children under 18 years of age with diagnosis of a skull-base sarcoma as confirmed with imaging and pathology were analyzed.

RESULTS

A total of 21 children were identified but only four children with skull-base sarcomas had diagnostic imaging available in whom computer-assisted volumetric analyses were generated. In these cases, CAD/CAM was used to plan surgical approaches and intraoperative radiotherapy, significantly aiding in treatment for these complicated pediatric cases.

CONCLUSION

CAD/CAM planning for oncologic resection has huge potential. Here we have shown its utility in pre-operative surgical planning and for administration of intraoperative radiation therapy. Future studies are needed to examine its value in facilitating intraoperative surgical management and patient outcomes, as well as cost effectiveness.

Quality of Life after Mandibular Reconstruction Using Free Fibula Flap and Customized Plates: A Case Series and Comparison with the Literature

A single-center retrospective study was conducted to assess health-related quality of life (HRQoL) in 23 consecutive patients undergoing mandibular reconstruction using the computer-aided design (CAD) and computer-aided manufacturing (CAM) technology, free fibula flap, and titanium patient-specific implants (PSIs). HRQoL was evaluated after at least 12 months of surgery using the University of Washington Quality of Life (UW-QOL) questionnaire for head and neck cancer patients. In the 12 single question domains, the highest mean scores were found for "taste" (92.9), "shoulder" (90.9), "anxiety" (87.5), and "pain" (86.4), whereas the lowest scores were observed for "chewing" (57.1), "appearance" (67.9), and "saliva" (78.1). In the three global questions of the UW-QOL questionnaire, 80% of patients considered that their HRQoL was as good as or even better than it was compared to their HRQoL before cancer, and only 20% reported that their HRQoL had worsened after the presence of the disease. Overall QoL during the past 7 days was rated as good, very good or outstanding by 81% of patients, respectively. No patient reported poor or very poor QoL. In the present study, restoring mandibular continuity with free fibula flap and patient-specific titanium implants designed with the CAD-CAM technology improved HRQoL.

Controlling and Stabilising Mandible During Reconstruction: Significance and Techniques

Objective

Stable and accurate positioning of condyle in the glenoid fossa is necessary for maintaining occlusion, facial symmetry and normal function of the temporomandibular joint following segmental resection of mandible. In non-reconstructed mandibular segments or those with fractured reconstruction plates the bony defect gets altered due to contraction or inadvertent muscular pull. This paper describes various techniques used to control dentate and edentate segments of the mandible during reconstruction following an ablative procedure.

Discussion

Secondary mandibular reconstruction has always been a tedious task for the surgeons. Several techniques have been described in literature ranging the use of external fixators, gunning splints and dentures for stabilising mandibular segments. Use of a pre-bent and adapted reconstruction plate is a common practice but may not be feasible in malignancies, benign tumours causing expansion and secondary reconstruction. The current advances in virtual surgical planning allows mandibular reconstruction to be performed in a simpler yet predictable manner.

Conclusion

The paper describes techniques ranging from twin K-wire placement to occlusal wafers, 3D printed splints and patient specific implants to enable accurate positioning of the segments and achieve pre-operative form. Advances in virtual surgical planning will continue to allow this field to evolve and to improve the quality of life of the patients.

Secondary Reconstruction of Head and Neck Cancer Defects-Principles in its Practice

Objective

Secondary reconstruction is requested by patients who have completed their head and neck cancer treatment. The reason for the request for reconstruction may be to improve the functional deficits, achieve aesthetic refinements or most commonly both. The article looks at various issues related to reconstruction in the secondary setting and suggesting the ways to approaching patients requesting secondary reconstruction.

Discussion

While considering secondary reconstruction, various factors need to be considered. These include issues related to the disease, the treatment received as well as the patient's comorbid conditions. Aggressive disease and multiple recurrences should deter from undertaking complex reconstructions. Lack of tissue pliability resulting in a woody neck due to radiation makes dissection difficult and wound healing poor. The reconstructive requirements include release of contractures inside the mouth, reconstruction of the missing jaws, replacement of the missing volume of the tongue and correction of the incompetent angle of mouth. Goals of reconstruction should be prioritized by the surgical team. Free soft tissue or bone containing flaps would be provided ideal tissue to meet the reconstructive requirements in secondary reconstruction. However, several impediments could exist for their safe use. Release of contractures and provision of adequate soft tissue should be given priority and must be addressed before bony reconstruction is contemplated.

Conclusion

Bony reconstruction of both mandible and maxilla is possible, with the former being more difficult to deliver good results due to the associated soft tissue fibrosis. Virtual surgical planning with the aid of Stereo lithographic models and planning software will improve the quality of bony reconstruction. Detailed counseling sessions involving patient and the family are essential before embarking on secondary reconstruction as the patient expectations and the surgical outcome may not be easy to match. However excellent improvement in function and appearance will be possible in many patients with appropriate reconstructive procedure.

The Precision of Different Types of Plates Fabricated With a Computer-Aided Design and Manufacturing System in Mandibular Reconstruction With Fibular-Free Flaps

Computer-assisted surgery (CAS) has been introduced to mandible reconstruction with fibular-free flap in cutting guide placement. When CAS cooperates with different plate fixations, the results show various degrees of errors by which this study aimed to evaluate. Mock surgeries were conducted in 3D-printed mandibles with 2 types of defects, limited or extensive, reconstructed from 2 ameloblastoma patients. Three types of fixations, miniplate, manually bending reconstruction plate, and patient-specific plate, are tested, each of which was performed 3 times in each type of defect, adding up to 18 surgeries. One with the least errors was selected and applied to patients whose 3D-printed mandibles were derived. Finally, in vivo errors were compared with the mock. In limited defect, average errors show no statistical significance among all types. In extensive defect, patient-specific plate had a significantly lower average condylar error than manually bending reconstruction plate and miniplate (8.09±2.52 mm vs. 25.49±2.72 and 23.13±13.54 mm, respectively). When patient-specific plate was applied in vivo , the errors were not significantly different from the mock. Patient-specific plates that cooperated with CAS showed the least errors. Nevertheless, manually bent reconstruction plates and miniplates could be applied in limited defects with caution.

Secondary Mandible Reconstruction with Computer-Assisted-Surgical Simulation and Patient-Specific Pre-Bent Plates: The Algorithm of Virtual Planning and Limitations Revisited

Despite the known advantages of virtual surgical planning and three-dimensional (3D) printing, translation of virtual planning to actual operation is a challenge, especially in secondary mandibular reconstruction. Patients who underwent secondary microvascular mandibular reconstruction were retrospectively reviewed and categorized into three categories as follows: (i) defect not crossing the midline (category I); (ii) defects crossing the midline with availability of previous imaging data (category II) and; (iii) defects crossing the midline with unavailability of previous imaging data (category III). The resulting 3D printed models were used as an effective guide for plate bending during secondary reconstruction surgery. Accuracy of the reconstruction was evaluated by superimposing post-operative images over virtual plan. Out of eleven patients, five were category I, three were category II, and three were category III. The mean linear discrepancy between the planned and post-operative position was measured. A Mann-Whitney U test was conducted to compare mean discrepancy among the groups showed no significant difference between group I and group II (p > 0.05) whereas comparison of groups I and II with group III showed a significant difference (p < 0.01). The proposed algorithm for the generation of defect template for manual plate bending during secondary reconstruction of mandibular defects is valid with acceptable accuracy in various defect configurations.

Mini-plate versus reconstruction bar fixation for oncologic mandibular reconstruction with free fibula flaps: A systematic review and meta-analysis

Introduction There is currently no consensus as to the comparative complication profiles of mini-plate (MP) and reconstruction bar (RB) osseous fixation in fibula flap mandibular reconstruction. The aim of this study is to compare complication rates associated with the use of MP versus RB fixation for vascularized fibula free flap (FFF) reconstruction of oncologic mandibular defects in an effort to better guide hardware utilization and pre-operative virtual surgical planning methods. Methods A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, EMBASE, and Cochrane Library databases were queried to identify studies related to FFF-based mandibular reconstruction with either MP or RB fixation. Primary endpoints of interest were plate complications, wound infection, mal- or non-union, and total flap loss. Complication rates were calculated as weighted proportions and compared via Fisher's exact testing. Results Sixteen studies met inclusion criteria, which examined 1,513 patients. Only three studies directly compared MP fixation with RB fixation. MP fixation was used in 828 (54.7%) cases and RB fixation in 685 (45.3%) cases. MP fixation demonstrated greater rates of plate-related complications (32.5% versus 18.8%, p < 0.01, respectively), fistula formation (15.8% versus 4.7%, p = 0.04), total flap loss (9.4% versus 4.7%, p = 0.02), partial flap loss (20.6% versus 6.1%, p < 0.01), and re-operation for vascular compromise (13.3% versus 4.0%, p < 0.01). Rates of infection, mal-union/non-union, and wound dehiscence were similar across both groups. Conclusion Our results suggest that MP use may be associated with higher rates of plate-related complications. Though limited by outcome reporting heterogeneity, this review can serve as a template for future investigations evaluating the safety profiles of MP and RB fixation in head and neck surgery.

Fabrication and evaluation of customized implantable drug delivery system for orthopedic therapy based on 3D printing technologies

A customized implantable drug delivery system with the dual functions of playing a supporting role and providing continuous bacteriostasis is of great importance during the treatment of bone defect diseases. The main objective of this study was to explore the potential of using three-dimensional (3D) printing technologies to fabricate customized implants. Ciprofloxacin hydrochloride (Cipro) was chosen as the model drug, and two printing technologies, semisolid extrusion (SSE) and fused deposition modeling (FDM) were introduced. Six kinds of implants with customized irregular shapes were printed via FDM technology. Two kinds of implants with customized dosages were constructed via SSE technology. In addition, three kinds of implants with customized internal structures were produced via FDM and SSE technologies. The data for morphology, dimensions and mechanical properties demonstrated satisfactory printability and good printing accuracy when applying SSE and FDM technologies to produce the customized implants. The dissolution curves indicated that the desired customized drug release could be achieved by designing the specific internal structures. The biocompatibility examination showed that the printed implants possessed outstanding biocompatibility. In conclusion, all results suggested that 3D printing technologies provide a feasible method and novel strategy to fabricate customized implantable drug delivery systems.

The Value of Three-Dimensional Modeling on Repositioning and Soft Tissue Filling in Microsurgical Reconstruction of Secondary Mandibular Defects: A Retrospective Study

Purpose

Secondary mandibular defect reconstruction is a challenging operation. It is performed rather rarely, as in most of the cases a primary reconstruction is preferable. Restoration of function and symmetry, in secondary reconstruction of mandibular defects, requires accurate repositioning of segments and appropriate soft tissue filling. The purpose of this study is to estimate the value of three-dimensional (3D) digital modeling to meet the above requirements, in secondary microsurgical reconstruction of mandibular defects.

Methods

Five cases of mandibular defects, with various degrees of asymmetry and dysfunction, were restored secondarily, with fibula flaps, after virtual reconstruction on a 3D model derived from their computed tomography, with the utilization of CAD-CAM software. Software reproduced symmetrical 3D models by mirroring the healthy side. Occlusion was restored by fine adjustments on 3D models and finally a reconstruction plate was pre-bent on them, prior to its sterilization for use in surgery. Three out of the five cases received an osteo-cutaneous flap, while in the other two patients, an osseous flap was used. Lower face symmetry, mouth opening, and main patient’s complaints were evaluated pre- and postoperatively to assess the value of the 3D modeling.

Results

All flaps survived. Hematoma occurred in two patients and was resolved after evacuation. In two patients, a fistula observed, was attributed to screw loosening, and treated after a surgical debridement and screw replacement. Intraoral exposure in the posterior part of the fibula flap was recorded in one patient, possibly from wound dehiscence due to tension of the intraoral tissue, and successfully covered with an ipsilateral nasolabial flap. The resulting symmetry and function were satisfactory in all the patients.

Conclusion

Secondary mandibular defects are often related with cosmetic disfigurement, misalignment of mandibular segments, and mandibular malfunction. For the correction of mandibular continuity, symmetry, and restoration of function, preoperative 3D modeling may be an important tool, according to our results.

Biomechanical analysis of mandibular defect reconstruction based on a new base-fixation system

Buccal titanium plate fixation is a common method for repairing mandibular defects. However, the method presents certain problems: the requirement of a large volume of titanium plate, a large number of fixation screws, a lengthy duration of the surgical operation, and exposure of the fixation plate which easily causes wound infection. In this study, a new base-fixation system was designed. Mandibular reconstruction was performed using the three-dimensional reconstruction package Mimics. In order to compare the newly designed base-fixation system and the common buccal-fixation system, the stress distributions and the displacement distributions of the whole model under two loading conditions were studied, based on the finite element analysis package ANSYS. The safety of the base-fixation titanium plate was evaluated. The results showed that although the maximum stress of the base-fixation titanium plate was higher than that of the buccal-fixation titanium plate, it was still less than the yield strength of titanium. Therefore, under the condition of applying 300 N of vertical occlusal loading, the base-fixation titanium plate displayed superior fixation ability without permanent deformation (and concomitant fixation failure). The results of the fatigue simulation analysis showed that the safety factor of the base-fixation titanium plate in the working state was 3.8 (>1.0), indicating that its fatigue performance met the application requirements. Compared with traditional buccal fixation, the novel base-fixation system has obvious advantages, suggesting its suitability as a new treatment method for clinical mandibular defect reconstruction.

Methods and Applications of 3D Patient-Specific Virtual Reconstructions in Surgery

3D modelling has been highlighted as one of the key digital technologies likely to impact surgical practice in the next decade. 3D virtual models are reconstructed using traditional 2D imaging data through either direct volume or indirect surface rendering. One of the principal benefits of 3D visualisation in surgery relates to improved anatomical understanding-particularly in cases involving highly variable complex structures or where precision is required.Workflows begin with imaging segmentation which is a key step in 3D reconstruction and is defined as the process of identifying and delineating structures of interest. Fully automated segmentation will be essential if 3D visualisation is to be feasibly incorporated into routine clinical workflows; however, most algorithmic solutions remain incomplete. 3D models must undergo a range of processing steps prior to visualisation, which typically include smoothing, decimation and colourization. Models used for illustrative purposes may undergo more advanced processing such as UV unwrapping, retopology and PBR texture mapping.Clinical applications are wide ranging and vary significantly between specialities. Beyond pure anatomical visualisation, 3D modelling offers new methods of interacting with imaging data; enabling patient-specific simulations/rehearsal, Computer-Aided Design (CAD) of custom implants/cutting guides and serves as the substrate for augmented reality (AR) enhanced navigation.3D may enable faster, safer surgery with reduced errors and complications, ultimately resulting in improved patient outcomes. However, the relative effectiveness of 3D visualisation remains poorly understood. Future research is needed to not only define the ideal application, specific user and optimal interface/platform for interacting with models but also identify means by which we can systematically evaluate the efficacy of 3D modelling in surgery.

Soft Tissue Dehiscence Associated with a Titanium Patient-Specific Implant: A Prosthetic Solution as an Alternative to Soft Tissue Grafting

Patients. This clinical report describes the detailed prosthodontic management of a 23-year-old male patient suffering from soft tissue complication following the placement of a 3d-printed titanium patient-specific implant. This implant was implemented simultaneously with the resection of a calcifying cystic odontogenic tumor related to the maxillary arch. Later, soft tissue dehiscence and implant exposure were encountered with subsequent food impaction, infection, and pus discharge. The treatment plan was to fabricate removable partial denture. The prosthesis was planned to be retained by bar and clip attachment on the patient-specific implant side, while on the other side, the removable prosthesis was allowed to engage two abutments with an embrasure clasp assembly in addition to covering the palatal tissues to offer protection for the soft tissue dehiscence against food impaction. Discussion. Soft tissue dehiscence and implant exposure are among the frequently reported complications associated with the patient-specific implant. The resulting infection complicates the prognosis of the implemented implant and necessitates, in some occasions, its removal. The selection of the removable prosthesis to cover soft tissue dehiscence was a conservative alternative to the implant removal as it protects the exposed titanium surface from food impaction while maintaining the implant functionality. Conclusion. Three-year follow-up showed complete resolution of the patient's complaints while fulfilling the patient's aesthetic and functional demands and indicates that the use of detachable overlay prosthesis could be one of the proposed treatment options.

3D Printed Personalized Medicine for Cancer: Applications for Betterment of Diagnosis, Prognosis and Treatment

Cancer treatment is challenging due to the tumour heterogeneity that makes personalized medicine a suitable technique for providing better cancer treatment. Personalized medicine analyses patient-related factors like genetic make-up and lifestyle and designs treatments that offer the benefits of reduced side effects and efficient drug delivery. Personalized medicine aims to provide a holistic way for prevention, diagnosis and treatment. The customization desired in personalized medicine is produced accurately by 3D printing which is an established technique known for its precision. Different 3D printing techniques exhibit their capability in producing cancer-specific medications for breast, liver, thyroid and kidney tumours. Three-dimensional printing displays major influence on cancer modelling and studies using cancer models in treatment and diagnosis. Three-dimensional printed personalized tumour models like physical 3D models, bioprinted models and tumour-on-chip models demonstrate better in vitro and in vivo correlation in drug screening, cancer metastasis and prognosis studies. Three-dimensional printing helps in cancer modelling; moreover, it has also changed the facet of cancer treatment. Improved treatment via custom-made 3D printed devices, implants and dosage forms ensures the delivery of anticancer agents efficiently. This review covers recent applications of 3D printed personalized medicine in various cancer types and comments on the possible future directions like application of 4D printing and regularization of 3D printed personalized medicine in healthcare.

Procedure Increasing the Accuracy of Modelling and the Manufacturing of Surgical Templates with the Use of 3D Printing Techniques, Applied in Planning the Procedures of Reconstruction of the Mandible

The application of anatomical models and surgical templates in maxillofacial surgery allows, among other benefits, the increase of precision and the shortening of the operation time. Insufficiently precise anastomosis of the broken parts of the mandible may adversely affect the functioning of this organ. Applying the modern mechanical engineering methods, including computer-aided design methods (CAD), reverse engineering (RE), and rapid prototyping (RP), a procedure used to shorten the data processing time and increase the accuracy of modelling anatomical structures and the surgical templates with the use of 3D printing techniques was developed. The basis for developing and testing this procedure was the medical imaging data DICOM of patients treated at the Maxillofacial Surgery Clinic of the Fryderyk Chopin Provincial Clinical Hospital in Rzeszów. The patients were operated on because of malignant tumours of the floor of the oral cavity and the necrosis of the mandibular corpus, requiring an extensive resection of the soft tissues and resection of the mandible. Familiarity with and the implementation of the developed procedure allowed doctors to plan the operation precisely and prepare the surgical templates and tools in terms of the expected accuracy of the procedures. The models obtained based on this procedure shortened the operation time and increased the accuracy of performance, which accelerated the patient’s rehabilitation in the further course of events.

The role of simulator and digital technologies in head and neck reconstruction

This review summarizes the development of digital technology in the field of head and neck surgeries. Advances in digital technology assist surgeons during preoperative planning, where they can simulate their surgeries with improvement in the resulting accuracy of the surgery. In addition to digital technologies having many applications in the surgical field, they can be used in medical devices, surgical and educational models, and tissue engineering.

Preparation and In Vitro Analysis of Craniofacial Titanium Implants Surfaces Produced by Additive 3D Printing and Conventional Manufacturing

Study Design

Surface finish of titanium patient-specific craniofacial implants is known to affect their acceptability and durability and relevant literature still inconclusive on the best surface finishing protocol.

Objectives

This study investigated surface topography of three-dimensionally (3D) printed and conventionally manufactured craniofacial titanium implants following non-contact 3D laser profile-meter analysis.

Methods

Seven groups of titanium specimens (n = 10) were prepared and their surfaces were treated differently and included sole or combined treatment of mechanical polishing, gritting with 50 micron AL₂O₃, cold acid treatment using nitric acid for 20 hours (70% w/w), etching using acidic solution (69% nitric and 48% hydrofluoric acids) for 10 minutes and then electro-chemically anodized in another acidic solution (85% orthophosphoric and 98%sulphuric acid). Eighth group included specimens that were 3D printed. 3D micro-roughness parameters Sa, Sp, Sv, and Sz were determined (μm) for each specimen. Data was analyzed using one way ANOVA and Dunett T3 post-hoc tests (p < 0.05).

Results

There were statistically significant effects of surface finishing protocols (p < 0.05). Sa values were 2.72-13.75 and specimens which were electroplated or mechanically polished and acid treated were the smoothest (p < 0.05). Sp was in the range 9.07-43.56 as sandblasting significantly roughened surfaces (p < 0.05). The same inferior effect was evident for the Sv (p < 0.05). The Sz values were 19.46-107.05 and was the highest for sandblasted surfaces (p < 0.05) and the lowest for surfaces of electro-chemical treatment (p < 0.05).

Conclusion

Titanium surfaces are affected by the finishing procedure and electro-chemical treatment or mechanical polishing combined with acid treatment produced clinically-favorable smooth surfaces.

Automatic Segmentation of Mandible from Conventional Methods to Deep Learning-A Review

Medical imaging techniques, such as (cone beam) computed tomography and magnetic resonance imaging, have proven to be a valuable component for oral and maxillofacial surgery (OMFS). Accurate segmentation of the mandible from head and neck (H&N) scans is an important step in order to build a personalized 3D digital mandible model for 3D printing and treatment planning of OMFS. Segmented mandible structures are used to effectively visualize the mandible volumes and to evaluate particular mandible properties quantitatively. However, mandible segmentation is always challenging for both clinicians and researchers, due to complex structures and higher attenuation materials, such as teeth (filling) or metal implants that easily lead to high noise and strong artifacts during scanning. Moreover, the size and shape of the mandible vary to a large extent between individuals. Therefore, mandible segmentation is a tedious and time-consuming task and requires adequate training to be performed properly. With the advancement of computer vision approaches, researchers have developed several algorithms to automatically segment the mandible during the last two decades. The objective of this review was to present the available fully (semi)automatic segmentation methods of the mandible published in different scientific articles. This review provides a vivid description of the scientific advancements to clinicians and researchers in this field to help develop novel automatic methods for clinical applications.

Impact of Planning Method (Conventional versus Virtual) on Time to Therapy Initiation and Resection Margins: A Retrospective Analysis of 104 Immediate Jaw Reconstructions

Simple Summary

Computer-aided design and manufacturing of osseous reconstructions are currently widely used in jaw reconstructive surgery, providing an improved surgical outcome and decreased procedural stumbling block. However, data on the influence of planning time on the time-to-surgery initiation and resection margin are missing in the literature. This retrospective, monocentric study compares process times from the first patient contact in hospital, time of in-house or out-of-house biopsy for tumor diagnosis and surgical therapy of tumor resection, and immediate reconstruction of the jaw with free fibula flaps (FFF). Two techniques for reconstruction are used: Virtual surgical planning (VSP) and non-VSP. A total of 104 patients who underwent FFF surgery for immediate jaw reconstruction from 2002 to 2020 are included. The study findings fill the gaps in the literature and obtain clear insights based on the investigated study subjects.

Abstract

Virtual surgical planning (VSP) and patient-specific implants are currently increasing for immediate jaw reconstruction after ablative oncologic surgery. This technique contributes to more accurate and efficient preoperative planning and shorter operation time. The present retrospective, single-center study analyzes the influence of time delay caused by VSP vs. conventional (non-VSP) reconstruction planning on the soft and hard tissue resection margins for necessary oncologic safety. A total number of 104 cases of immediate jaw reconstruction with free fibula flap are included in the present study. The selected method of reconstruction (conventionally, non-VSP: n = 63; digitally, VSP: n = 41) are analyzed in detail. The study reveals a statistically significant (p = 0.008) prolonged time to therapy initiation with a median of 42 days when the VSP method compared with non-VSP (31.0 days) is used. VSP did not significantly affect bony or soft tissue resection margin status. Apart from this observation, no significant differences concerning local tumor recurrence, lymph node, and distant metastases rates are found according to the reconstruction method, and affect soft or bone tissue resection margins. Thus, we conclude that VSP for immediate jaw reconstruction is safe for oncological purposes.

Improving mandibular reconstruction by using topology optimization, patient specific design and additive manufacturing?-A biomechanical comparison against miniplates on human specimen

In this study, topology optimized, patient specific osteosynthesis plates (TOPOS-implants) are evaluated for the mandibular reconstruction using fibula segments. These shape optimized implants are compared to a standard treatment with miniplates (thickness: 1.0 mm, titanium grade 4) in biomechanical testing using human cadaveric specimen. Mandible and fibula of 21 body donors were used. Geometrical models were created based on automated segmentation of CT-scans of all specimens. All reconstructions, including cutting guides for osteotomy as well as TOPOS-implants, were planned using a custom-made software tool. The TOPOS-implants were produced by electron beam melting (thickness: 1.0 mm, titanium grade 5). The fibula-reconstructed mandibles were tested in static and dynamic testing in a multi-axial test system, which can adapt to the donor anatomy and apply side-specific loads. Static testing was used to confirm mechanical similarity between the reconstruction groups. Force-controlled dynamic testing was performed with a sinusoidal loading between 60 and 240 N (reconstructed side: 30% reduction to consider resected muscles) at 5 Hz for up to 5 · 10⁵ cycles. There was a significant difference between the groups for dynamic testing: All TOPOS-implants stayed intact during all cycles, while miniplate failure occurred after 26.4% of the planned loading (1.32 · 10⁵ ± 1.46 · 10⁵ cycles). Bone fracture occurred in both groups (miniplates: n = 3, TOPOS-implants: n = 2). A correlation between bone failure and cortical bone thickness in mandible angle as well as the number of bicortical screws used was demonstrated. For both groups no screw failure was detected. In conclusion, the topology optimized, patient specific implants showed superior fatigue properties compared to miniplates in mandibular reconstruction. Additionally, the patient specific shape comes with intrinsic guiding properties to support the reconstruction process during surgery. This demonstrates that the combination of additive manufacturing and topology optimization can be beneficial for future maxillofacial surgery.

Recurrent Convolutional Neural Networks for 3D Mandible Segmentation in Computed Tomography

Purpose: Classic encoder–decoder-based convolutional neural network (EDCNN) approaches cannot accurately segment detailed anatomical structures of the mandible in computed tomography (CT), for instance, condyles and coronoids of the mandible, which are often affected by noise and metal artifacts. The main reason is that EDCNN approaches ignore the anatomical connectivity of the organs. In this paper, we propose a novel CNN-based 3D mandible segmentation approach that has the ability to accurately segment detailed anatomical structures. Methods: Different from the classic EDCNNs that need to slice or crop the whole CT scan into 2D slices or 3D patches during the segmentation process, our proposed approach can perform mandible segmentation on complete 3D CT scans. The proposed method, namely, RCNNSeg, adopts the structure of the recurrent neural networks to form a directed acyclic graph in order to enable recurrent connections between adjacent nodes to retain their connectivity. Each node then functions as a classic EDCNN to segment a single slice in the CT scan. Our proposed approach can perform 3D mandible segmentation on sequential data of any varied lengths and does not require a large computation cost. The proposed RCNNSeg was evaluated on 109 head and neck CT scans from a local dataset and 40 scans from the PDDCA public dataset. The final accuracy of the proposed RCNNSeg was evaluated by calculating the Dice similarity coefficient (DSC), average symmetric surface distance (ASD), and 95% Hausdorff distance (95HD) between the reference standard and the automated segmentation. Results: The proposed RCNNSeg outperforms the EDCNN-based approaches on both datasets and yields superior quantitative and qualitative performances when compared to the state-of-the-art approaches on the PDDCA dataset. The proposed RCNNSeg generated the most accurate segmentations with an average DSC of 97.48%, ASD of 0.2170 mm, and 95HD of 2.6562 mm on 109 CT scans, and an average DSC of 95.10%, ASD of 0.1367 mm, and 95HD of 1.3560 mm on the PDDCA dataset. Conclusions: The proposed RCNNSeg method generated more accurate automated segmentations than those of the other classic EDCNN segmentation techniques in terms of quantitative and qualitative evaluation. The proposed RCNNSeg has potential for automatic mandible segmentation by learning spatially structured information.

Comparison of surgical outcomes between primary plate and fibular flap transfer for reconstruction of segmental mandibular defects

PURPOSE

Although two ways of reconstruction have been reviewed for a long period, comparison of large sample size with nearly randomized patient selection is rare. Here, we compare the surgical outcomes of these two methods from two large medical institutes.

METHODS

Totally 176 patients were included from two medical centers with different protocols, 62 patients from MacKay Hospital repair defects with fibula flaps using reconstruction plates. Also 114 patients from Kaohsiung ChangGung Hospital treat with reconstruction plates combine anterior lateral thigh flaps, in which 12 cases had secondary fibula flap after plate exposure. Electronic medical records were reviewed retrospectively. Short (3-12 months) and long-term (>12 months) outcomes were evaluated.

RESULTS

Short-term evaluation revealed that the secondary fibula had a higher rate of vascular complications (33 vs. 6%, p = .02). Primary fibula had a higher risk of post reconstructive surgical debridement (60 vs. 40%, p = .018). Long-term follow-up revealed radiation therapy significantly worsened bone healing (p = .03). Primary fibula had a lower rate of screw loosening (14.0 vs. 40.3%, p = .002). Radiation therapy did not increase the plate exposure rate among the groups (33 vs. 27%, p = .389). Disease free survival showed no significant difference between two groups (53.1 ± 3.5 vs. 47.8 ± 2.8 months, p = .317).

CONCLUSION

Primary fibula reconstruction should be considered whenever possible to reduce the risk of late complications and simplifies the management after a potential plate exposure. Notably, radiation therapy apparently has no significant effect on plate exposure rate both in ALT or fibula groups.

Partial and Total Flap Failure after Fibula Free Flap in Head and Neck Reconstructive Surgery: Retrospective Analysis of 180 Flaps over 19 Years

Fibula free flap (FFF) is widely used in head and neck reconstructive surgery and is considered as a standard and therapy of choice after ablative cancer surgery. The aim of this retrospective monocenter study was to determine the success rates of fibula free flaps for jaw reconstruction after ablative tumor surgery. The disease course of patients who underwent jaw reconstructive surgery with FFF from January 2002 to June 2020 was evaluated regarding the flap success rate. Flap failure was analyzed in detail and categorized into two groups: partial flap failure (PFF) and total flap failure (TFF). A total of 180 free fibular flaps were performed over the last 19 years and a total of 36 flap failures were recorded. TFF occurred in n = 20 (56.6%) and PFF in n = 16 cases (44.4%) cases. No statistically significant differences were found concerning patients' age at flap transfer, sex, BMI, ASA-Score, preoperative non-virtual or virtual surgical planning (non-VSP vs. VSP), and time of reconstruction (immediately vs. delayed). Duration of hospitalization shows statistically significant differences between both groups (p = 0.038), but no differences concerning operating time and duration on Intensive Care Unit (ICU). Partial flap failure appears to be underreported in literature. Sub- and complete failure of the skin paddle leads to clinical complaints like uncovered bone segments and plate exposure. Partial or complete FFF failure lead to infections on the recipient site and prolonged wound healing and therefore may cause a delay of the beginning of adjuvant radiation therapy (RT). PFF of hard tissue can be induced by RT.

Factors influencing CAD/CAM accuracy in fibula free flap mandibular reconstruction

Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has improved the functional and morphological results of mandibular reconstructive surgery. The purpose of this study was to objectively assess this technology and factors affecting its accuracy. Fibula free flap mandibular reconstruction was performed in 26 cases using CAD/CAM technology at the Maxillofacial Unit of Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, between June 2014 and February 2018. We evaluated the technology’s accuracy by comparing the virtual surgical planning STL file (planned-target mesh) with the STL file from an early postoperative CT scan (postoperative-achievement mesh) in each case. The STL files were imported into Geomagic Studio 2016 (Geomagic GmbH). According to the position of the reconstruction plate (fixed reference point), we assessed deviations at the right condyle, right gonion, gnathion, left gonion and left condyle, calculating mean, minimum and maximum error values. Mean error values ranged from 0.6 to 2.2 mm; they were ≥ 2 mm in only 2 (7.7%) cases. The midline area (symphysis-gnathion) showed the least variation (1.05 ± 0.92 mm), and the gonion area showed the greatest variation (right and left means of 1.6 and 1.46 mm, respectively). Among all possible factors that could affect CAD\CAM accuracy, nothing showed significant influence, including the timing of reconstruction, site and size of the defect and malignancy status. CAD/CAM technology has a high degree of accuracy and reproducibility for microvascular reconstruction of mandibular defects using fibula free flaps, regardless of the defect site and length, use of a single- or double-barrel graft or timing of reconstruction.

Extended and unusual indications in jaw reconstruction with the fibula flap: An overview based on our 30-year experience

Since the introduction of fibula flap as a reconstructive technique, an evolution of indications has been observed. Our first report of a traumatic mandibular reconstruction using fibula flap was in 1992. The vast majority of indications for surgery, are: malignant tumors, benign neoplasms, osteoradionecrosis and traumas. Nevertheless, extended indications have been described such as the treatment of dentoalveolar defect without bone discontinuity or reconstruction of maxilla defect up to type III (A and B), according to Cordeiro's classification. Unusual indications include cleft palate malformations with bone discontinuity less than 6 cm. Moreover, a particular attention should be focus on fibula flap harvest with more innovative technologies than traditional use of monopolar or bipolar and their advantages in pre and postoperative management.

3D printed bone models in oral and cranio-maxillofacial surgery: a systematic review

AIM

This systematic review aimed to evaluate the use of three-dimensional (3D) printed bone models for training, simulating and/or planning interventions in oral and cranio-maxillofacial surgery.

MATERIALS AND METHODS

A systematic search was conducted using PubMed® and SCOPUS® databases, up to March 10, 2019, by following the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol. Study selection, quality assessment (modified Critical Appraisal Skills Program tool) and data extraction were performed by two independent reviewers. All original full papers written in English/French/Italian and dealing with the fabrication of 3D printed models of head bone structures, designed from 3D radiological data were included. Multiple parameters and data were investigated, such as author's purpose, data acquisition systems, printing technologies and materials, accuracy, haptic feedback, variations in treatment time, differences in clinical outcomes, costs, production time and cost-effectiveness.

RESULTS

Among the 1157 retrieved abstracts, only 69 met the inclusion criteria. 3D printed bone models were mainly used as training or simulation models for tumor removal, or bone reconstruction. Material jetting printers showed best performance but the highest cost. Stereolithographic, laser sintering and binder jetting printers allowed to create accurate models with adequate haptic feedback. The cheap fused deposition modeling printers exhibited satisfactory results for creating training models.

CONCLUSION

Patient-specific 3D printed models are known to be useful surgical and educational tools. Faced with the large diversity of software, printing technologies and materials, the clinical team should invest in a 3D printer specifically adapted to the final application.

Printed titanium implants in UK craniomaxillofacial surgery. Part II: perceived performance (outcomes, logistics, and costs)

This second part explores perceptions and understanding of clinical performance, turnaround, and costs for printed titanium implants or plates in common procedures, evaluating both 'in-house' and 'outsourced' CAD-CAM pathways. A cross-sectional study, supported by the British Association of Oral and Maxillofacial Surgeons (BAOMS) and a national trainee-led recruitment team, was conducted over 14 weeks. A total of 132 participants took part (demographic data is reported in Part I). For fibular-flap mandibular reconstruction, most participants (69% - 91%) perceived printed titanium as superior to intraoperatively or preoperatively hand-bent plates for surgical duration, accuracy, dental restorability, and aesthetics. There was less agreement about complications and plate-failure risks. Most perceived printed plates to be superior to traditional wafer-based maxillary osteotomy for surgical duration (61%) and maxillary positioning (60%). For orbital floor repair, most perceived improvements in surgical duration (83%, especially higher-volume operators p=0.009), precision (84%), and ease of placement (69%). Rarely (less than 5%) was any outcome rated inferior to traditional techniques for any procedure. Perceived turnaround times and costs were variable, but the greatest consensus was for two-segment fibular-flap reconstructions and orbital floor repair. Industry estimates were generally consistent between two company representatives, but manufacturing-only costs differed when using in-house (departmental) designers. Costs and turnaround times are questionable barriers since few understand 'real-world' figures. Designing in-house can dramatically alter costs. Improved accuracy and surgical duration are common themes but biomechanical benefits are less-well understood. This study paints a picture of the potentially routine applications and benefits of printed titanium, capacity for uptake, understanding amongst surgeons, and areas for improvement.

Reconstruction of mandible using a computer-designed 3D-printed patient-specific titanium implant: a case report

Reconstruction of mandibular defects after trauma or tumor resection is one of the most challenging problems facing maxillofacial surgeons. Historically, various autografts and alloplastic materials have been used in the reconstruction of these types of defects. The use of individualized designed biomaterials has opened new possibilities in reconstructive surgery, and now, it is possible to use the patient's computed tomography (CT) to construct patient-specific implants (PSIs). A case of a large mandibular tumor resection and reconstruction of the defect using a customized 3D-printed titanium implant is described. The treatment had excellent postoperative esthetic and functional results without complications. CONCLUSION: Because titanium implants are customizable, easily workable especially with help of 3D virtual planning techniques, bioinert, and nonporous, they represent an ideal alloplastic material for mandibular reconstruction.

Three-Dimensionally Printed Patient-Specific Surgical Plates Increase Accuracy of Oncologic Head and Neck Reconstruction Versus Conventional Surgical Plates: A Comparative Study

Background

Surgeons are pursuing accurate head and neck reconstruction to enhance aesthetic and functional outcomes after oncologic resection. This study aimed to investigate whether accuracy of head and neck reconstruction is improved with the use of three-dimensionally (3D)-printed patient-specific surgical plates compared with conventional plates.

Methods

In this comparative study, patients were prospectively recruited into the study group (3DJP16) with 3D-printed patient-specific surgical plates. The patients in control group with conventional surgical plates were from a historic cohort in the same unit. The primary end point of the study was the accuracy of head and neck reconstruction. The secondary end points were accuracy of osteotomy, intraoperative blood loss, total operative time, and length of hospital stay.

Results

The study recruited of 33 patients, including 17 in the study group and 16 in the control group. The patients’ baseline characteristics were similar between the two groups. The absolute distance deviation of the maxilla or mandible was 1.5 ± 0.5 mm in the study group and 2.1 ± 0.7 mm in the control group [mean difference, − 0.7 mm; 95% confidence interval (CI) − 1.1 to − 0.3; p = 0.003], showing superior accuracy of reconstruction for the patients with 3D-printed patient-specific surgical plates. Improved accuracy of reconstruction also was detected in terms of bilateral mandibular angles and bone grafts. Concerning the secondary end points, the accuracy of the osteotomy was similar in the two groups. No difference was found regarding intraoperative blood loss, total operative time, or length of hospital stay.

Conclusions

This is the first study to prove that compared with conventional plates, 3D-printed patient-specific surgical plates improve the accuracy of oncologic head and neck reconstruction.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08732-y) contains supplementary material, which is available to authorized users.

CAD-CAM vs conventional technique for mandibular reconstruction with free fibula flap: A comparison of outcomes

INTRODUCTION

Mandibular reconstruction always pose a challenge to the reconstructive surgeon. With the use of Computer aided designing and computer aided manufacturing (CAD-CAM) it is now possible to reconstruct mandibular defects to near normal configuration with good function and aesthetic outcomes.

AIMS/OBJECTIVES

To compare the efficacy of CAD-CAM technique vs conventional technique in mandibular reconstruction with free fibula flap.

MATERIALS AND METHODS

40 consecutive patients that required mandibular reconstruction using free fibula flap were included in the study. All patients were treated using CAD-CAM technique and then compared retrospectively with 40 patients treated with conventional technique. Comparison was done between total intraoperative time, aesthetic outcome and post-operative occlusion.

RESULTS

Total intraoperative time in the CAD-CAM group was significantly reduced (562 min) as compared to the conventional group (662 min). Patients in the CAD-CAM group also obtained a better Aesthetic score (3.6/5) when compared to the conventional group (2.5/5). Postoperative malocclusion was noted in 1 patient in the CAD-CAM group as opposed to 6 patients in the conventional group.

CONCLUSION

Use of CAD-CAM technology in mandibular reconstruction with free fibula flap offers reduced surgical time with precise and accurate reconstruction that produces better functional and aesthetic outcomes.

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.

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.

Effectiveness of computer-assisted virtual planning, cutting guides and pre-engineered plates on outcomes in mandible fibular free flap reconstructions: a systematic review protocol

OBJECTIVE

The objective of this review is to synthesize the best available evidence on the outcomes of mandibular fibular free flap (MFFF) reconstructions using computer-assisted techniques versus traditional freehand techniques.

INTRODUCTION

Fibular free flaps are the most commonly used free flap for mandible reconstruction and are considered best practice for mandible reconstructions following resection of head and neck cancers. There are several reported advantages of computer-assisted MFFF reconstructions, including increased accuracy, decreased operation time, decreased ischemia time, decreased overall cost and improved patient outcomes. It is important to assess the advantages and potential harms of these techniques in a systematic review.

INCLUSION CRITERIA

Eligible studies will consider patients of all ages undergoing MFFF reconstruction. Studies will compare computer-assisted techniques to traditional freehand techniques for the primary outcomes of flap failure, patient-reported outcomes and bony resection margin status. Studies published in English from 2008 will be included. Experimental, quasi-experimental, prospective and retrospective cohort, case-control and analytical cross-sectional studies will be considered.

METHODS

MEDLINE, Embase, Scopus and the Cochrane Central Register of Controlled Trials will be searched. Gray literature sources will include Google Scholar and the World Health Organization International Clinical Trials Registry Platform. Two independent reviewers will screen titles and abstracts, assess full-text papers against the inclusion criteria, evaluate methodological quality using standardized critical appraisal instruments and extract data using a customized form. If possible, data will be pooled for statistical meta-analysis, and a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Summary of Findings will be presented.

Partial mandibulectomy without bony reconstruction in patients with oropharyngeal or mouth cancer

Aim of the study

Resection of tumours of the oral cavity has significant consequences relating to function and aesthetic properties. Advancements in surgical techniques and microvascular surgery have enabled reconstructive outcomes to reach those of pre-surgery levels with good functional and aesthetic results. However, reconstructive options are not without complications.

Material and methods

We report the outcome of 23 patients with large tumours of the oral cavity or floor of the mouth, who underwent resection of the tumour and parts of the mandible without bony reconstruction. The patient population consisted of 19 oropharyngeal carcinomas and four floor of the mouth cancers, all of which had stage cT4 (six female and 17 male patients), and with an average patient age of 59.8 years. The pre- and postoperative ability to open the mouth, level of pain while masticating, mastication function pre and post-surgery, and the aesthetic outcome post-surgery were measured.

Results

The results obtained were deemed pleasantly acceptable by the patients, from aesthetic, functional, and analgesic points of view.

Discussion

A thorough preoperative work up is required and discussion with a multidisciplinary team is a necessity. This treatment option is more acceptable to the patient than would be expected and provides a satisfactory functional and aesthetic outcome. Therefore, we believe that partial mandibulectomy without bony reconstruction is an acceptable management option for a carefully selected group of patients who may not be suitable for the extensive surgery involved with bony reconstruction.

The Use of Patient-Specific Implants in Oral and Maxillofacial Surgery

This article summarizes the current use of patient-specific implants in oral and maxillofacial surgery.

Advanced biomaterials for repairing and reconstruction of mandibular defects

Mandibles are the largest and strongest bone in the human face and are often severely compromised by mandibular defects, compromising the quality of life of patients. Mandibular defects may result from trauma, inflammatory disease and benign or malignant tumours. The reconstruction of mandibular defect has been a research hotspot in oral and maxillofacial surgery. Although the principles and techniques of mandibular reconstruction have made great progress in recent years, the development of biomedical materials is still facing technical bottleneck, and new materials directly affect technological breakthroughs in this field. This paper reviews the current status of research and application of various biomaterials in mandibular defects and systematically elaborates different allogeneic biomaterial-based approaches. It is expected that various biomaterials, in combination with new technologies such as digital navigation and 3D printing, could be tuned to build new types of scaffold with more precise structure and components, addressing needs of surgery and post-reconstruction. With the illustration and systematization of different solutions, aims to inspire the development of reconstruction biomaterials.

Condyle dislocation following mandibular reconstruction using a fibula free flap: complication cases

Background

Condylar dislocation can arise as a complication in patients who required mandibular and/or condylar reconstruction and were operated on with fibula free flap (FFF) using surgical guides designed using simulation surgery. Surgeons should be aware of the complications in these present cases when planning and performing reconstructions as well as predicting prognoses.

Cases presentation

Two cases showed condylar dislocation in mandibular reconstruction using a FFF fixed with a reconstruction plate. Three cases showed condylar dislocation in mandibular reconstruction using a fibula free flap fixed with a mini-plate.

Conclusion

Despite the lack of clinical symptoms in these cases following mandibular reconstruction using an FFF, the mandibular condyle was severely displaced away from the glenoid fossa. A surgeon must have sufficient time to consider the use of a long flap with thickness similar to that of the mandible, ways to minimize span and bending, and methods of fixation. The patient, moreover, should be educated on condylar dislocation. Customized CAD/CAM-prototyped temporomandibular condyle-connected plates may be a good alternative even if virtual simulation surgery is to be performed before surgery. These considerations may help reduce the incidence of complications after mandibular reconstruction.

Resin adjustment of three-dimensional printed thermoset occlusal splints: Bonding properties - Short communication

OBJECTIVES

To evaluate the interfacial adhesion of an autopolymerizing acrylic resin to 3D printed thermoset occlusal splints compared to thermoplastic occlusal splints.

MATERIALS AND METHODS

Cylinders made of an autopolymerizing acrylic resin were adhered to 3D printed thermoset and also to thermoplastic plates. A different surface treatment and three storage conditions were used: dry, 7 days water-storage and 14 days water-storage. Bond strength test (so-called shear-bond strength test) was afterward performed.

RESULTS

ANOVA (R2 = 0.764) revealed significant differences in bond strength according to material (p < 0.001) and storage (p < 0.001) but not for surface treatment (p = 0.202).

CONCLUSIONS

The bond strength of autopolymerizing acrylic resin to 3D printed thermoset plates is higher when compared to thermoplastic plates. Bonding between acrylic resin and 3D printed splints was high enough for clinical applications.conclusion CLINICAL RELEVANCE: The bond strength values obtained in this study with 3D printed plates were at the level of generally accepted adequate bonding values for prosthetic materials.