Restoration of masticatory function by microsurgically revascularized iliac crest bone grafts using enosseous implants

Minimally invasive myo-osseous chimeric DCIA-flap without crest, spine and skin to reconstruct composite defects of the mandible using virtual surgical planning and CAD/CAM technology

BACKGROUND

The medial approach for minimally invasive harvesting of a deep circumflex iliac artery (DCIA) flap is described for reconstruction of the jaw. The associated preservation of the crest of the ilium prevents the raising of the abdominal internal oblique muscle (IO) in a standard fashion. However, reconstructive surgery of composite mandibular defects includes bone and soft tissue. To achieve this goal, we combined this technique with a new perforator-based raising of the IO for reconstruction of intraoral soft tissue.

METHODS

In this study, we present eight cases of patients with composite mandibular defects who underwent the myo-osseous DCIA flap procedure with an IO perforator. Virtual surgical planning was employed to preplan the size and configuration of the graft. Cutting guides were made using CAD/CAM technology. The surgical procedure followed the described medial approach for minimally invasive harvesting, leaving the iliac crest, spine, and skin intact. In addition, we completely cut and isolated the IO with its sole attachment being the ascending branch of the DCIA. We used either a surgical guide with a slot to lead through both the transverse branch of the bone and the ascending branch of the IO or a surgical guide consisting of 2 parts.

RESULTS

In all instances, the flap successfully survived with a 100% success rate. There were no signs of infection, wound opening, or bleeding in either patient. Furthermore, the patients did not exhibit permanent complications related to the donor site. The internal oblique perforator flap exhibited remarkable integration in all patients and underwent rapid transformation. Notably, the flap developed keratinized mucosa (KM) that closely resembled the attached gingiva.

CONCLUSION

Our study demonstrated the effectiveness of a medial approach for harvesting a newly designed more flexible chimeric myo-osseous deep circumflex iliac artery flap. By incorporating virtual surgical planning and custom-made cutting guides for obtaining deep circumflex iliac artery flaps through the medial route along with an internal oblique perforator flap, we have established a highly promising method for the rehabilitation of patients with composite mandibular defects. This approach not only improves functional outcomes, but also enhances aesthetic results to maintain patients' quality of life.

Complications in Deep Circumflex Iliac Artery-Related Vascularized Free Iliac Flap

BACKGROUND

Since its first application in 1978, the vascularized free iliac flap (VFIF) has gradually become a mainstay for tissue defect reconstruction. However, the complications associated with harvesting the bone flap and its corresponding reconstruction surgery cannot be overlooked.

METHODS

We conducted a narrative review through literature search to identify the types, incidence, influencing factors, measurement methods, and treatment approaches of complications related to DCIA-related VFIF.

RESULTS

We propose the "LIP" rule (Loss, Injury, Postoperative) for classifying donor site complications. For the four most common recipient sites, mandible, maxilla, extremities, and hip joint, we list the common and rare complications that may occur. Additionally, we provide a summary of the methods and advances in preventing these complications.

CONCLUSIONS

We comprehensively describe the complications observed in the application of DCIA-related VFIF and introduce the "LIP" principle and other strategies to minimize or avoid adverse outcomes.

Volumetric Bone Changes in Double Barrel Vascularized Fibula Flap Used for Mandibular Reconstruction: A Randomized Clinical Trial

AIM

To assess the volumetric bone changes in double barrel vascularized fibular flap used for mandibular reconstruction using 3D miniplate versus 3D titanium mesh tray.

MATERIALS AND METHODS

Twenty patients seeking mandibular reconstruction were selected for this 2-arm parallel randomized clinical trial with a 1:1 allocation ratio. Both groups underwent double-barrel fibula free flap for mandibular reconstruction with fixation of the superior barrel to the inferior barrel using a Titanium mesh (Group A) or a 3D plate (Group B). The primary outcome was volumetric bone changes (immediate to 6 months postoperatively).

RESULTS

Eleven participants (55%) were females, and 9 participants (45%) were males. The mean age of patients in group A was (28.8±8.9) years, while group B was (30.7±11.4) years. There was a statistically significant difference within each group in the volumetric bone changes with means of -7942.1±1804.8 mm 3 and -6288.8±2607.3 for groups A and B, respectively. The difference between both groups was statistically insignificant with the mean of -1653.3±1002.8 mm 3 . The percentage of mean volumetric change relative to immediate postoperatively for group A was -14.15%, while in group B was -11.01%.

CONCLUSIONS

Both the titanium mesh tray and the 3D plate were effective in the fixation of the superior barrel of the vascularized fibular flap for mandibular reconstruction. There was no difference between both modalities regarding volumetric bone changes.

Evaluation of zirconia implants in fibula and deep circumflex iliac artery flaps: a prospective 1.5-year follow-up study

OBJECTIVES

Follow-up results of modern zirconia implants inserted in fibula free and deep circumflex iliac artery (DCIA) flaps with fixed dentures are scarce. This study aimed to evaluate crestal bone changes and the survival rate of zirconia implants for up to 1.5 years of prospective follow-up.

MATERIALS AND METHODS

Ten patients with six fibula and four DCIA flaps underwent reconstruction in the lower and upper jaws using vascularized composite flaps and were treated with zirconia implants. Peri-implant bone resorption was measured using radiographic images that were taken immediately after implant surgery (T1) and after three (T2), 12 (T3), and 18 months (T4).

RESULTS

Between the day of operation and T3, a significant increase in distance was recorded for the fibula flaps. After occlusal loading (T2) of 41 zirconia implants for up to 1.5 years, no significant bone loss in each flap was observed overall. An overall survival rate of 96.56% was reported.

CONCLUSIONS

When comparing both composite flaps, no significant difference in periimplant bone levels was measured between the same timepoints.

CLINICAL RELEVANCE

For fixed dentures, modern zirconia implants can be used in the DCIA and fibula flaps, however further long-term data is necessary.

Analysis of changes in bone mineral density and cortical bone thickness after reconstruction of the mandible with fibula, is condyle preservation a critical influence factor?

OBJECTIVE

This study aimed to investigate the features of bone mineral density (BMD) and cortical bone thickness in grafted fibula.

MATERIALS AND METHODS

Eighty-six patients who underwent mandibular reconstruction using vascularized fibula flaps were enrolled, all of whom were followed up at 3, 6, and 12 months after surgery. The patients were grouped according to whether the condyle was preserved. BMD and cortical bone thickness were also measured.

RESULTS

Condyle-preserved group consisted of 65 patients and condyle-unpreserved group consisted of 21 patients. There was a significant correlation between thickness and BMD, which was significantly correlated with follow-up time. One year after surgery, the BMD of the condyle-preserved group decreased from 1029.61 ± 156.01 mg/cm3 to 978.6 ± 141.90 mg/cm3, and thickness decreased from 3.29 ± 0.65 mm to 2.72 ± 0.72 mm. BMD of the condyle-unpreserved group decreased from 1062.21 ± 126.01 mg/cm3 to 851.26 ± 144.38 mg/cm3, and thickness decreased from 3.46 ± 0.89 mm to 2.56 ± 0.73 mm. In the condyle-preserved and unpreserved groups, the absorption rates of BMD were 3.29 ± 11.97% and 17.09 ± 12.42% at 12 months, respectively, and the rate of thickness was 20.7 ± 11.45% and 26.39 ± 12.23% at 12 months, respectively.

CONCLUSION

BMD and thickness showed a decreasing trend over time. Preserving the condyle can slow bone resorption of the fibula. Regarding implant restoration, we recommend doctors to perform the treatment within 6-12 months after surgery in order to effectively manage bone resorption.

CLINICAL RELEVANCE

Our study found that condylar preservation can decrease the absorption rate of BMD and cortical bone thickness, helping doctors make better clinical decisions.

TRIAL REGISTRATION NUMBER

ChiCTR2300069661 (March 22, 2023).

Development of a universal cutting guide for raising deep circumflex iliac artery flaps

PURPOSE

The deep circumflex iliac crest flap (DCIA) is used for the reconstruction of the jaw. For fitting of the transplant by computer-aided planning (CAD), a computerized tomography (CT) of the jaw and the pelvis is necessary. Ready-made cutting guides save a pelvic CT and healthcare resources while maintaining the advantages of the CAD planning.

METHODS

A total of 2000 CTs of the pelvis were divided into groups of 500 by sex and age (≤ 45 and > 45 years). Three-dimensional (3D) pelvis models were aligned and averaged. Cutting guides were designed on the averaged pelvis for each group and an overall averaged pelvis. The cutting guides and 50 randomly selected iliac crests (10 from each group and 10 from the whole collective) were 3D printed. The appropriate cutting guide was mounted to the iliac crest and a cone beam CT was performed. The thickness of the space between the iliac crest and the cutting guide was evaluated.

RESULTS

Overall the mean thickness of the space was 2.137 mm and the mean volume of the space was 4513 mm3. The measured values were significantly different between the different groups. The overall averaged group had not the greatest volume, maximum thickness and mean thickness of the space.

CONCLUSION

Ready-made cutting guides for the DCIA flap fit to the iliac crest and make quick and accurate flap raising possible while radiation dose and resources can be saved. The cutting guides fit sufficient to the iliac crest and should keep the advantages of a standard CAD planning.

The dental implant survival rate in 18 patients with post-operation revolutionary jaw reconstruction using free fibular flap, dental implants, and overdentures

Background/purpose

This retrospective study assessed the risks and complications associated with dental implants after jaw surgery and radiotherapy for large defects, highlighting challenges for reconstructive surgeons and prosthetic dentists.

Materials and methods

From 2002 to 2008, National Taiwan University's Department of Maxillofacial Surgery used preoperative stereolithographic models and microvascular flaps for mandibular reconstruction in 18 patients with defects from ameloblastoma or advanced gingival cancer. They received free fibular flap grafts, followed by 46 osseointegrated dental implants. Patient outcomes, monitored for up to 60 months, were assessed through clinical and radiographic evaluations of implant success.

Results

The overall survival rate of dental implants following tumor surgery and radiotherapy was 84.8%. Seven implants failed due to peri-implantitis (3), tumor recurrence (2), and osteoradionecrosis (ORN) (2). The ameloblastoma group did not contribute to implant failure, with 4 implant failures in the stage III gingival cancer group, and 3 implant failures in the stage IV gingival cancer group.

Conclusion

Following segmental mandibulectomy for mandible lesions, free fibular bone graft reconstruction restored mandible continuity, while subsequent dental implantation and overdenture fabrication restored occlusion and aesthetics for patients. Besides considering treatment strategies for ameloblastoma groups, similar approaches can be extended to oral cancer patients undergoing post-operative reconstruction. However, additional considerations (peri-implant soft tissue condition, tumor recurrence, ORN, etc.) are necessary for oral cancer patients predisposed to dental implant failure post-surgery.

A study on the morphology of iliac crest based on the objectives of jaw bone defect reconstruction

OBJECTIVES

to understand the morphological characteristics of iliac crest and provide advice and assistance for jaw bone reconstruction with iliac bone flap by evaluating the thickness and curvature of iliac crest.

MATERIALS AND METHODS

100 patients who had taken Spiral CT of the Abdominal region before surgeries between 2020 and 2022 were included in this study. 3D reconstruction images of the iliac bones were created. 5 vertical planes perpendicular to the iliac crest were made every 2 cm along the centerline of the iliac crest (VP2 ~ VP10). On these vertical planes, 4 perpendicular lines were made every 1 cm along the long axis of the iliac crest (D1 ~ D4). The thicknesses at these sites, horizontal angle (HA) of iliac crest and the distance between inflection point and the central point of anterior superior iliac spine (DIA) were measured.

RESULTS

The thickness of iliac bone decreased significantly from D1 ~ D4 on VP6 ~ VP10 and from VP2 ~ VP10 on D3 and D4 level (P<0.05). HA of iliac crests was 149.13 ± 6.92°, and DIA was 7.36 ± 1.01 cm. Iliac bone thickness, HA and DIA had very weak or weak correlation with patient's age, height and weight.

CONCLUSIONS

The average thicknesses of iliac crest were decreased approximately from front to back, from top to bottom. The thickness and curvature of the iliac crest were difficult to predict by age, height and weight.

CLINICAL RELEVANCE

Virtual surgical planning is recommended before jaw bone reconstruction surgery with iliac bone flap, and iliac crest process towards alveolar process might be a better choice.

Bone Tissue Engineering (BTE) of the Craniofacial Skeleton, Part I: Evolution and Optimization of 3D-Printed Scaffolds for Repair of Defects

Bone tissue regeneration is a complex process that proceeds along the well-established wound healing pathway of hemostasis, inflammation, proliferation, and remodeling. Recently, tissue engineering efforts have focused on the application of biological and technological principles for the development of soft and hard tissue substitutes. Aim is directed towards boosting pathways of the healing process to restore form and function of tissue deficits. Continued development of synthetic scaffolds, cell therapies, and signaling biomolecules seeks to minimize the need for autografting. Despite being the current gold standard treatment, it is limited by donor sites' size and shape, as well as donor site morbidity. Since the advent of computer-aided design/computer-aided manufacturing (CAD/CAM) and additive manufacturing (AM) techniques (3D printing), bioengineering has expanded markedly while continuing to present innovative approaches to oral and craniofacial skeletal reconstruction. Prime examples include customizable, high-strength, load bearing, bioactive ceramic scaffolds. Porous macro- and micro-architecture along with the surface topography of 3D printed scaffolds favors osteoconduction and vascular in-growth, as well as the incorporation of stem and/or other osteoprogenitor cells and growth factors. This includes platelet concentrates (PCs), bone morphogenetic proteins (BMPs), and some pharmacological agents, such as dipyridamole (DIPY), an adenosine A 2A receptor indirect agonist that enhances osteogenic and osteoinductive capacity, thus improving bone formation. This two-part review commences by presenting current biological and engineering principles of bone regeneration utilized to produce 3D-printed ceramic scaffolds with the goal to create a viable alternative to autografts for craniofacial skeleton reconstruction. Part II comprehensively examines recent preclinical data to elucidate the potential clinical translation of such 3D-printed ceramic scaffolds.

Feasibility analysis of bone density evaluation with Hounsfield unit value after fibula flap reconstruction of jaw defect

BACKGROUND

Implant-supported dentures have become an essential means of restoring occlusal function after jaw reconstruction. Bone mineral density (BMD) may influence the success rate of implant denture restorations. This study aimed to explore whether the Hounsfield unit (HU) value can be used to monitor the changing trend of fibular BMD after jaw reconstruction.

RESULTS

A total of 54 patients who underwent maxillar/mandibular reconstruction with a fibula flap were included in this study. There was a significant correlation between the HU value and BMD at 1 week, 3 months, and 6 months after surgery, and both were significantly correlated with follow-up time. The difference between each pair of absorption rates (DAR) was less than 10% in 66.7% and 75.9% of patients at 3 and 6 months; however, the DAR was more than 20% in 12% and 13.8% of patients at 3 and 6 months, respectively.

CONCLUSIONS

There is a significant correlation between HU value and BMD. The HU value can be used to roughly reflect the fibular BMD changing trend in a group of patients as opposed to an individual, and the HU value is not equivalent to BMD.

TRIAL REGISTRATION

ChiCTR, ChiCTR2300069661, retrospectively registered on 22 March 2023. Retrospectively registered, https://www.chictr.org.cn/showproj.html?proj=188953 .

Iliac crest towards alveolar processes or mandibular inferior margin in mandibular reconstruction with a vascularized iliac bone flap: which is better?

OBJECTIVE

The study aims to compare differences among iliac bone flaps with different iliac crest orientations for the repair of mandibular defects with an aim to analyze their advantages, disadvantages, and effects.

MATERIAL AND METHODS

Clinical data and computed tomography scans of all patients who underwent iliac bone flap repair of the mandible in Peking University School and Hospital of Stomatology from January 2016 to April 2021 were collected. Patients were divided into the iliac crest towards alveolar process (Group A) and the iliac crest towards mandibular inferior margin (Group B). Software was used to measure corresponding indicators. The results obtained for the groups were statistically analyzed.

RESULTS

The study included 78 patients (25 and 53 in groups A and B, respectively). The symmetry of the LC-type defect was better in group A (p < 0.05). The all-bone width of the alveolar process side in group A was greater than 6 mm; in 15 cases of group B, the width was less than 6 mm (p < 0.05). The intermaxillary distance of two sites were higher in group B (p < 0.05). The bone cortical thickness was significantly thicker in group A (p < 0.05).

CONCLUSION

One year after the mandibular body defect was reconstructed with a vascularized iliac bone flap, the iliac crest towards alveolar process group showed better bone symmetry, width, intermaxillary distance, and cortical thickness to meet the planting requirements.

CLINICAL RELEVANCE

The use of an iliac crest towards alveolar process may be a better approach for mandible reconstruction.

Computer-Assisted Dental Implant Placement Following Free Flap Reconstruction: Virtual Planning, CAD/CAM Templates, Dynamic Navigation and Augmented Reality

Image-guided surgery, prosthetic-based virtual planning, 3D printing, and CAD/CAM technology are changing head and neck ablative and reconstructive surgical oncology. Due to quality-of-life improvement, dental implant rehabilitation could be considered in every patient treated with curative intent. Accurate implant placement is mandatory for prosthesis long-term stability and success in oncologic patients. We present a prospective study, with a novel workflow, comprising 11 patients reconstructed with free flaps and 56 osseointegrated implants placed in bone flaps or remnant jaws (iliac crest, fibula, radial forearm, anterolateral thigh). Starting from CT data and jaw plaster model scanning, virtual dental prosthesis was designed. Then prosthetically driven dental implacement was also virtually planned and transferred to the patient by means of intraoperative infrared optical navigation (first four patients), and a combination of conventional static teeth supported 3D-printed acrylic guide stent, intraoperative dynamic navigation, and augmented reality for final intraoperative verification (last 7 patients). Coronal, apical, and angular deviation between virtual surgical planning and final guided intraoperative position was measured on each implant. There is a clear learning curve for surgeons when applying guided methods. Initial only-navigated cases achieved low accuracy but were comparable to non-guided freehand positioning due to jig registration instability. Subsequent dynamic navigation cases combining highly stable acrylic static guides as reference and registration markers result in the highest accuracy with a 1–1.5-mm deviation at the insertion point. Smartphone-based augmented reality visualization is a valuable tool for intraoperative visualization and final verification, although it is still a difficult technique for guiding surgery. A fixed screw-retained ideal dental prosthesis was achieved in every case as virtually planned. Implant placement, the final step in free flap oncological reconstruction, could be accurately planned and placed with image-guided surgery, 3D printing, and CAD/CAM technology. The learning curve could be overcome with preclinical laboratory training, but virtually designed and 3D-printed tracer registration stability is crucial for accurate and predictable results. Applying these concepts to our difficult oncologic patient subgroup with deep anatomic alterations ended in comparable results as those reported in non-oncologic patients.

Comparison of augmented reality and cutting guide technology in assisted harvesting of iliac crest grafts - A cadaver study

BACKGROUND

Harvesting vascularized bone grafts with computer-assisted surgery represents the gold standard for mandibular reconstruction. However, current augmented reality (AR) approaches are limited to invasive marker fixation. This trial compared a markerless AR-guided real-time navigation with virtually planned and 3D printed cutting guides for harvesting iliac crest grafts.

MATERIAL AND METHODS

Two commonly used iliac crest transplant configurations were virtually planned on 10 cadaver hips. Transplant harvest was performed with AR guidance and cutting guide technology. The harvested transplants were digitalized using cone beam CT. Deviations of angulation, distance and volume between the executed and planned osteotomies were measured.

RESULTS

Both AR and cutting guides accurately rendered the virtually planned transplant volume. However, the cumulative osteotomy plane angulation differed significantly (p = 0.018) between AR (14.99 ± 11.69°) and the cutting guides (8.49 ± 5.42°). The cumulative osteotomy plane distance showed that AR-guided navigation had lower accuracy (2.65 ± 3.32 mm) than the cutting guides (1.47 ± 1.36 mm), although without significant difference.

CONCLUSION

This study demonstrated the clinical usability of markerless AR-guided navigation for harvesting iliac crest grafts. Further improvement of accuracy rates might bring clinical implementation closer to reality.

A retrospective study on mandibular reconstruction using iliac crest free flap

PURPOSE

To assess the availability, success rate and complications of microvascular iliac crest free flap for reconstruction of mandibular segmental defects.

METHODS

In this retrospective-descriptive study, we report patients who had undergone segmental mandibular resection for pathologic lesions and received reconstruction with iliac crest microvascular free flap between 2016 and 2019. Clinical and demographic data of all the cases were collected. Success was regarded as complete consolidation of the bone graft in panoramic radiograph. Postoperative complications were defined as major or minor based on the need for intervention. T-test, Kolomogorov_Smirnov, and multivariate analysis were used and the p-value<0.05 was considered to be statistically significant.

RESULTS

Of all 30 patients, 16 were women and 14 were men with an average age of 27.2 years (range 14-40). Patients were followed for 12-60 month (mean: 38.4). One flap was lost due to unsalvageable venous thrombosis. Six other cases had post-op complications while smoking and diabetes were associated with more complications (P = 0.036). Twenty-three patients received primary reconstruction which was more successful than secondary ones (P = 0.003). Osteogenic sarcoma was associated with greater risk of complications (P < 0.01).

CONCLUSIONS

The results of this study suggest that iliac crest microvascular free flap serves as a promising option for the reconstruction of mandibular defects, providing excellent contour and acceptable success rate with low donor site morbidity. Future studies will focus on the role of systemic diseases in post-op complications and flap failures.

Contemporary Approach to Locally Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Surgical management of locally advanced oral cavity squamous cell carcinomas (OCSCC) has long been recognized as a primary treatment modality. Technological advances have led to significant improvements in our surgical approach, from improvement in the visualization of tumors to more efficient and precise reconstruction. Here, we review the latest technological advances in surgical extirpation and reconstruction of locally advanced OCSCCs.

RECENT FINDINGS

The focus of technological innovation in surgical extirpation has been on improving visualization, with the use of intraoperative ultrasound for margin delineation, intraoperative navigation, narrow-band imaging, and the use of fluorescence. Though early, these are promising steps to ensuring complete resection of the cancer. Advances in reconstruction have been centered on the incorporation of computer assisted design, manufacturing, and virtual surgical planning, allowing for more complex three-dimensional defects to be expeditiously reconstructed. As these technologies are still under development, their impact on oncologic outcomes are not yet robustly defined; however, as technology continues to advance and become more widely available, new technologies will undoubtedly become integrated into enhancing surgical precision and planning.

Changes in oral health-related quality of life after oral rehabilitation with dental implants in patients following mandibular tumor resection

Oral rehabilitation with prosthodontic treatment considerably influences the well-being and quality of life of patients after ablative oral tumor surgery. This study evaluated the effects of implant-supported prostheses (ISPs) on oral health-related quality of life (OHRQoL) and chewing ability in 10 patients who requested ISPs after mandibular oral tumor resection. OHRQoL was assessed using the Japanese version of the Oral Health Impact Profile (OHIP-49) before and one year after ISP placement. Chewing ability, including self-assessed masticatory ability and occlusal force, was examined at one year after ISP placement. The initial mean total OHIP-49 score of 65.3 ± 9.79 decreased to 46.0 ± 8.14 at one year after ISP placement. Mean OHIP-49 score decreased in all domains, whereas self-assessed masticatory ability increased within one year of ISP placement. There were no significant differences between prosthesis types with respect to the mean OHIP-49 score or self-assessed masticatory ability. In conclusion, ISP placement improves OHRQoL and the self-assessed masticatory ability. Moreover, the prosthesis type might not significantly affect OHRQoL.

Review of surgical resection and reconstruction in head and neck cancer. Traditional versus current concepts

This review summarizes the development of head and neck cancer resection and reconstruction. The developments in the treatment of cancer patients are reflected in their surgical outcomes, in addition to functional and aesthetic improvements. New technologies, such as surgical simulation and planning, minimally invasive surgery, and microsurgery have been added to the field to improve surgical resection of the tumor and reconstruction. The field is still growing to optimize the management of head and neck cancer.

Factors Affecting Dental Rehabilitation Following Jaw Reconstruction With Free-Fibular Graft In Patients With Head and Neck Cancer

Existing anatomic factors play a significant role in affecting the possibility of dental rehabilitation in head and neck cancer patients undergoing free-fibular graft reconstruction. An observational, cross-sectional study was initiated to evaluate factors affecting dental rehabilitation following free-fibular graft jaw reconstruction in head and neck cancer patients.Patients who had undergone jaw reconstruction with free-fibular graft, requiring dental rehabilitation were recruited. Irradiated, reconstructed patients who had completed at least 1 year since the last dose of radiotherapy and nonradiated patients who had completed 6 months since reconstruction were recruited. Patients who had undergone soft-tissue reconstruction or free-fibular graft in non-condyle sparing resections were excluded. Patient's demographic data, disease and treatment-related data were obtained. An intra-oral examination was carried out to evaluate anatomic variables affecting dental rehabilitation. Descriptive statistical analyses were carried out to study demographic data. Logistic regression analysis was carried out using Pearson χ test and Fisher exact test. Estimates of regression coefficient and their standard errors with 95% confidence interval were calculated.Total of 138 patients were enrolled and considered for prosthetic rehabilitation. A review of the frequency-based data revealed that 30% (n = 41) patients were considered suitable for prosthetic rehabilitation. On multivariate logistic regression analysis, morbidity of radiotherapy (P = 0.01), interference to placement of implants by reconstruction plates and screws (P = 0.023), unfavorable diagnostic maxilla-mandibular relationship (P = 0.011), and obliterated vestibule (P = 0.001) were statistically established (P < 0.05) as the most significant reasons for not carrying out dental rehabilitation in patients who had undergone free-fibular graft reconstruction.

Impact of 3D virtual planning on reconstruction of mandibular and maxillary surgical defects in head and neck oncology

PURPOSE OF REVIEW

This review describes the advances in 3D virtual planning for mandibular and maxillary reconstruction surgical defects with full prosthetic rehabilitation. The primary purpose is to provide an overview of various techniques that apply 3D technology safely in primary and secondary reconstructive cases of patients suffering from head and neck cancer.

RECENT FINDINGS

Methods have been developed to overcome the problem of control over the margin during surgery while the crucial decision with regard to resection margin and planning of osteotomies were predetermined by virtual planning. The unlimited possibilities of designing patient-specific implants can result in creative uniquely applied solutions for single cases but should be applied wisely with knowledge of biomechanical engineering principles.

SUMMARY

The high surgical accuracy of an executed 3D virtual plan provides tumor margin control during ablative surgery and the possibility of planned combined use of osseus free flaps and dental implants in the reconstruction in one surgical procedure. A thorough understanding of the effects of radiotherapy on the reconstruction, soft tissue management, and prosthetic rehabilitation is imperative in individual cases when deciding to use dental implants in patients who received radiotherapy.

Reconstruction of the bony chin using sagittal split osteotomies of the remaining mandible - A new technique for a special indication: Case report

There are several indications for resecting the bony chin, such as squamous cell carcinoma, sarcoma, or benign tumors of the jaw such as ameloblastoma. Several techniques for reconstruction of the bony chin, such as the use of metal plates and also revascularized free bone grafts of the iliac crest, fibula, or scapula, are common. In the case of poor vascular supply, however, alternative techniques may be necessary. In this report, a new technique is described using pedicled bone flaps from both sagittally split mandibular stumps following chin resection. These flaps were pedicled on the mylohyoid muscles and advanced to restore the continuity of the mandible. An advantage of this procedure was minimization of the soft tissue defect, making repair easier. Morbidity of the resection and reconstruction was thus reduced, and recovery of the patient was very quick.

Jaw in a Day: State of the Art in Maxillary Reconstruction

BACKGROUND

Reconstruction of maxillary defects following tumor extirpation is challenging because of combined aesthetic and functional roles of the maxilla. One-stage reconstruction combining osseous free flaps with immediate osseointegrated implants are becoming the standard for mandibular defects, and have similar potential for maxillary reconstruction.

METHODS

A woman with maxillary Ewing sarcoma successfully treated at age 9 with neoadjuvant chemotherapy, right hemimaxillectomy, and obturator prosthetic reconstruction presented for definitive reconstruction, complaining of poor obturator fit, and hypernasality. Her reconstruction was computer-simulated by a multidisciplinary team, consisting of left hemi-Lefort I advancement and right maxillary reconstruction with a free fibula flap with immediate osseointegrated implants and dental prosthesis.

RESULTS

Full dental restoration, midface projection, and oral fistula corrections were achieved in 1 operative stage using this approach.

CONCLUSIONS

This patient demonstrates a successful approach for maxillary reconstruction using computer-planned orthognathic surgery with free fibula reconstruction and immediate osseointegrated implants with dental prosthesis.

Evaluation of bone resorption in fibula and deep circumflex iliac artery flaps following dental implantation: A three-year follow-up study

Long-term results of dental implant treatment in fibula free and deep circumflex iliac artery (DCIA) free flaps are scarce. The purpose of this study was to assess and compare peri-implant bone resorption of vascularized bone flaps treated with dental implants. A total of 28 patients, 14 fibula and 14 DCIA flaps, respectively, underwent reconstruction of the lower and upper jaw by the use of vascularized bone flaps and were treated with dental implants. Peri-implant bone resorption was measured using digital panographs up to 3 years. Radiographic pictures were taken immediately after implant surgery before prosthetic rehabilitation (T0), the second after 6-12 months (T1), the third after 13-24 months (T2), and the fourth after 25-36 months (T3). Over a period of 3 years, implant resorption changed significantly over time (p_D1 = 0.0113, p_D2 = 0.0232, p_D3 = 0.0143). However, a significant difference in overall resorption between implants with fibula flaps and DCIA could not be detected for the patient average or within the implant-level analysis. Flaps presented minimal resorption from beneath (mean resorption DCIA 0.65, fibula = 0.26). Strong peri-implant bone resorption changed significantly over time. However, no significant difference was observed between fibula and DCIA flaps.

A Revised Approach for Mandibular Reconstruction With the Vascularized Iliac Crest Flap Using Virtual Surgical Planning and Surgical Navigation

PURPOSE

The purpose of this study was to describe a revised approach for mandibular reconstruction with vascularized iliac crest flap using virtual surgical planning and surgical navigation.

PATIENTS AND METHODS

Preoperative maxillofacial and iliac non-contrast-enhanced computed tomography (CT) scans were acquired, and CT data were imported into ProPlan CMF software (Materialise, Leuven, Belgium). We performed virtual mandibulectomy and superimposed the 3-dimensional iliac image on the mandibular defect. The surgeon shaped the iliac flap according to virtual parameters and the stereomodel. Surgical navigation was used to check and correct the shaped segments. The position of the osteotomy lines and relevant parameters regarding the shape of the iliac flap also were provided to the surgeon. After computer simulation, a reconstructed mandibular stereomodel was manufactured. A reconstruction plate was prebent and fixed on this model using titanium screws. The model was scanned, data were imported into ProPlan CMF, the mandible was segmented, and data were imported into the intraoperative navigation system. Then, the model was registered with the original CT data, and the reconstruction plate was eliminated. Navigation data were exported into a universal serial bus drive, which was connected to the terminal working station during surgery. Intraoperative navigation was used to implement the virtual plan for patients. The sagittal, coronal, axial, and 3-dimensional reconstruction images displayed by the navigation system were used to accurately determine the osteotomy sites and osteotomy trajectory during surgery. Surgical probe guidance was used to mark the osteotomy line and transfer the virtual procedure to real-time surgery.

RESULTS

Using our method, we precisely recovered the original configuration of the mandible. The shift in the reconstructed mandible and plate was less than 5 mm.

CONCLUSIONS

We provided a new method for mandibular reconstruction with vascularized iliac crest flap and an individual reconstruction plate using computer-assisted techniques involving surgical navigation, which have the potential to improve the clinical outcomes of this procedure.

3D Finite Element Study on: Bar Splinted Implants Supporting Partial Denture in the Reconstructed Mandible

AIM:

This study aimed to estimate the stress patterns induced by the masticatory loads on a removable prosthesis supported and retained by bar splinted implants placed in the reconstructed mandible with two different clip materials and without clip, in the fibula-jaw bone and prosthesis using finite element analysis.

METHODS:

Two 3D finite element models were constructed, that models components were modeled on commercial CAD/CAM software then assembled into finite element package. Vertical loads were applied simulating the masticatory forces unilaterally in the resected site and bilaterally in the central fossa of the lower first molar as 100N (tension and compression). Analysis was based on the assumption full osseointegration between different types of bones, and between implants and fibula while fixing the top surface of the TMJ in place.

RESULTS:

The metallic bar connecting the three implants is insensitive to the clips material. Its supporting implants showed typical behavior with maximum stress values at the neck region. Fibula and jaw bone showed stresses within physiologic, while clips material effect seems to be very small due to its relatively small size.

CONCLUSION:

Switching loading force direction from tensile to compression did-not change the stresses and deformations distribution, but reversed their sign from positive to negative.

Prosthodontic Considerations in Post-cancer Reconstructions

The restoration of function after oncologic surgery of the oral cavity constitutes one of the major challenges facing head and neck oncology. Within the general objective of securing esthetic as well as functional reconstructions, dental rehabilitation is crucial for achieving a good outcome. Adequate dental rehabilitation allows the patient to chew food and considerably improves speech and swallowing. These reconstructions will be driven biologically or prosthetically following surgical design and outcome.

Computer-Aided Mandibular Reconstruction With Vascularized Iliac Crest Bone Flap and Simultaneous Implant Surgery

The intention of oral rehabilitation in patients with mandibular defects is an early prosthetic treatment with maximum possible functionality and high accuracy. The present study describes a new computer-aided technique for mandibular reconstruction using a free vascularized iliac flap and simultaneous insertion of dental implants into the flap while it is still pedicled at the donor site. Based on preoperative computerized tomography data of the facial skeleton and the iliac crest donor site, a surgical guide transferred the virtual plan including information on the transplant dimensions and shape as well as the position of the dental implants into real-time surgery. Using postoperative computerized tomography scans, the actual situation were compared with the preoperative simulation. A mean difference of 0.75 mm (SD ± 0.72) for the flap shape and 0.70 mm (SD ± 0.44) for the implant position analysis was determined. A calculation of the closest point distance showed a surface deviation of &lt;2 mm for the shape analysis in 93.3% of the values and &lt;1 mm for implant position in 75.2% of the values. The mean angular deviation was 3.65°. Virtual surgical planning is a suitable method for mandibular reconstruction with vascularized iliac crest flaps and simultaneous implant surgery. It can be used to restore the anatomy of the mandible with a high accuracy and can help to shorten subsequent dental rehabilitation.

Predictable dental rehabilitation in maxillomandibular reconstruction with free flaps. The role of implant guided surgery

The reconstruction of maxillomandibular defects secondary to oral cancer surgery, represent a great challenge for Maxillofacial surgeons. During the last decades the reconstructive surgery has experimented a big advance due to the development of the microsurgical techniques. At present, we are able to reconstruct complex defects using free flaps that provide both soft and bone tissue. Fibula, iliac crest and scapula free flaps have been the three classic options for the maxillomandibular reconstruction owing to the amount of bone that this flaps provide, allowing the posterior dental rehabilitation with implants. Today, our objective it is not only the aesthetic reconstruction, but also the functional reconstruction of the patients enhancing their life quality. Guided implant surgery in free flap reconstructed patients has become an essential tool, helping to define the exact position of the dental implant in the flap. In this way it is possible to look for the areas with better bone conditions, avoiding the osteosynthesis material used to fixate the flap with the native bone and deciding the best biomechanical option, in terms of number and situation of the implants, for the future dental prostheses. In summary, using the guided implant surgery, it is possible to design an exact and predictable dental implant rehabilitation in patients with oral cancer who are reconstructed with free microvascular flap, resulting in an optimal aesthetic and functional result.

The accuracy of computer-assisted primary mandibular reconstruction with vascularized bone flaps: iliac crest bone flap versus osteomyocutaneous fibula flap

Background

The intention of mandibular reconstruction is to restore the complex anatomy with maximum possible functionality and high accuracy. The aim of this study was to evaluate the accuracy of computer-assisted surgery in primary mandibular reconstruction with an iliac crest bone flap compared with an osteomyocutaneous fibula flap.

Materials and methods

Preoperative computed tomography data of the mandible and the iliac crest or fibula donor site were imported into a specific surgical planning software program. Surgical guides were manufactured using a rapid prototyping technique for translating the virtual plan, including information on the transplant dimensions and shape, into real-time surgery. Using postoperative computed tomography scans and an automatic surface-comparison algorithm, the actual postoperative situation was compared with the preoperative virtual simulation.

Results

The actual flap position showed a mean difference from the virtual plan of 2.43 mm (standard deviation [SD] ±1.26) and a surface deviation of 39% <2 mm and 15% <1 mm for the iliac crest bone flap, and a mean difference of 2.18 mm (SD ±1.93) and a surface deviation of 60% <2 mm and 37% <1 mm for the osteomyocutaneous fibula flap. The position of the neomandible reconstructed with an osteomyocutaneous fibula flap indicated a mean difference from the virtual plan of 1.25 mm (SD ±1.31) and a surface deviation of 82% <2 mm and 57% <1 mm, in contrast to a mean difference of 1.68 mm (SD ±1.25) and a surface deviation of 63% <2 mm and 38% <1 mm for the neomandible after reconstruction with an iliac crest bone flap. For shape analysis, a similarly high accuracy could be calculated for both flaps.

Conclusion

Virtual surgical planning is an effective method for mandibular reconstruction with vascularized bone flaps, and can help to restore the anatomy of the mandible with high accuracy in position and shape. It seems that primary mandibular reconstruction with the osteomyocutaneous fibula flap is more accurate compared with the vascularized iliac crest bone flap.

Evaluation of computer-assisted mandibular reconstruction with vascularized iliac crest bone graft compared to conventional surgery: a randomized prospective clinical trial

BACKGROUND

Computer-assisted surgery plays an increasingly important role in mandibular reconstruction, ensuring the best possible masticatory function and aesthetic outcome.

METHODS

Twenty patients were randomly assigned to computer-assisted or conventional mandibular reconstruction with vascularized iliac crest bone graft in a prospective study design.Virtual surgical planning was based on preoperative CT-data using specific surgical planning software. A rapid prototyping guide transferred the virtual surgery plan to the operation site. During surgery the transplant ischemic time, reconstruction time, time for shaping the transplant and amount of bone removed were measured. Additionally, the difference in the intercondylar distance before and after surgery was calculated.

RESULTS

Computer-assisted surgery shortened the time of transplant ischemia (P < 0.005) and defect reconstruction (P < 0.001) compared to conventional surgery. The time to saw and shape the transplant at the donor site was shorter using conventional surgery (P < 0.005); therefore, the overall time for surgery didn't change (P = 0.527). In the computer-assisted group, the amount of bone harvested equaled the defect size, whereas the transplant size in the conventional group exceeded the defect site by 16.8 ± 5.6 mm (P < 0.001) on average. The intercondylar distance before compared to after surgery was less affected in the computer-assisted than in the conventional group (P < 0.001).

CONCLUSIONS

The presented study shows that computer-assisted surgery can help reduce the time for mandibular defect reconstruction and consequently the transplant ischemic time. In the computer-assisted group, the iliac crest donor site defect was downsized and the postoperative condyle position was less altered, reducing possible risks of postoperative complications and donor site morbidity.

TRIAL REGISTRATION

DRKS00005181.

[Therapeutic strategies for the reconstruction of extensive mandibular defects]

Tumours of the mandibular bone or adjacent soft tissue often necessitate mandibular resection. Subsequent primary bone reconstruction to achieve optimal functional and aesthetic results has been made possible by microvascular surgical techniques and now represents the international gold standard. Microvascular reanastomosis of autologous bone grafts from the iliac crest or fibula is the most common procedure for reconstruction of the mandible. The localisation and extent of the expected defect, as well as a patient's overall condition and ability to tolerate long surgical procedures must be carefully considered before deciding upon the course of treatment. Additional microvascular reanastomosis of soft tissue flaps and stereolithographic models facilitate preoperative planning and broaden the surgical spectrum. Following successful reconstruction of the bone, insertion of dental implants and prosthetic rebuilding are required to complete rehabilitation, including restoration of the patient's ability to chew and speak. The authors recommend specialised oncologic centres for such complex surgical reconstructions.

Computer-assisted zygoma reconstruction with vascularized iliac crest bone graft

BACKGROUND

The reconstruction of zygoma is a challenge with regard to aesthetic and reconstructive demands.

METHODS

Pre-operative CT data were imported into specific surgical planning software. The mirror-imaging technique was used. A surgical guide transferred the virtual surgery plan to the operation site, whereby it fitted uniquely to the iliac donor site. A postoperative CT scan was obtained for comparing the actual postoperative graft position and shape with the pre-operative virtual simulation.

RESULTS

A mean difference of 0.71 mm (SD ± 1.42) for the shape analysis and 3.53 mm (SD ± 3.14) for the graft position was determined. The calculation of the closest point distance showed a surface deviation of < 2 mm for the shape analysis with 83.6% of values and for the graft position with 35.7% of values.

CONCLUSION

Virtual surgical planning is a suitable method for zygoma reconstruction with vascularized iliac crest bone graft, with good accuracy for restoring the three-dimensional anatomy.

Comparison of outcome of microvascular bony head and neck reconstructions using the fibular free flap and the iliac crest flap

Several microvascular free flaps are available for reconstruction of the osseous components after resections for head and neck cancer. We have prospectively evaluated patients treated by bony microsurgical reconstruction to identify predictors of adverse outcomes for delayed wound healing and failure of free flaps. All patients from July 2007 to June 2011 who had reconstructions with microvascular fibular or iliac crest flaps immediately after resection of the tumour were evaluated. There were a total of 156 bony free flaps: 120 (77%) fibular and 36 (23%) iliac crest flaps. A total of 133 (85%) were successful. Delayed wound healing was more common with the iliac crest flap (p=0.01) at the intraoral site (p=0.04). Significantly more iliac crest free flaps failed (p=0.02). Anastomosis to the facial artery (p=0.05) and facial vein (p=0.04), and duration of overall operating time were associated with a significantly higher risk of failure of the flap. Patients with cancer of the head and neck who require microsurgical bony reconstruction are at increased risk of postoperative complications. Significantly more complications were found with the iliac crest flap, whereas the fibular flap was associated with a significantly longer operating time.

Functional long-term results after the harvest of vascularised iliac bone grafts bicortically with the anterior superior iliac spine included

The aim of this study was to evaluate the postoperative morbidity at the donor site and the long-term outcome after the harvest of bicortical iliac bone grafts, including the iliac crest and the anterior superior iliac spine (ASIS), by using a confirmed score. We retrospectively examined 54 consecutive patients who had had vascularised iliac bone grafts harvested to reconstruct different parts of the mandible. We used the Harris Hip Score to evaluate objectively the long-term postoperative morbidity at the donor site. Of 54 patients, 20 were female (37%) and 34 male (63%), with a mean age of 49 years (range 12-81). The causes of the bony defects were malignancy (n=37, 69%), benign tumours (n=7, 13%), osteomyelitis (n=9, 17%), and atrophy of the alveolar ridge (n=1, 2%). All transplants healed adequately. A total of 38/52 patients (73%) had a score of more than 80 points, which defines clinical success. Vascularised iliac bone grafts offer excellent bony dimensions with optimal shape to be used for reconstruction of different parts of the mandible. They can be harvested bicortically, including the iliac crest and the ASIS, with acceptable morbidity at the donor site. The Harris Hip Score is an appropriate tool for the evaluation of long-term impairment at the donor site after the harvest of vascularised iliac bone grafts, and it could be used to compare the results of different studies.

Computer-assisted mandibular reconstruction with vascularized iliac crest bone graft

BACKGROUND

The intention of mandibular reconstructive surgery is to achieve maximum possible functionality, which means the restoration of masticatory function and speech with a good esthetic result.

METHODS

We compared five computer-assisted mandibular reconstructions with 15 conventional mandibular reconstructions performed using vascularized iliac crest bone grafts. Based on preoperative cone beam computed tomography (CBCT) or CT data imported into the specific surgical planning software, a surgical guide was designed by rapid prototyping that helped to exactly translate the virtual surgery plan into the operation site whereby it fit uniquely to the iliac donor site. The ischemic time of the graft was measured intraoperatively and the difference between the amount of bone removed and the amount of bone required was determined. In addition, 3 months after surgery patients had to score the esthetics of their outer appearance using a visual analog scale.

RESULTS

In all patients the graft fit perfectly into the mandibular defect without major adjustments. The time for the shaping process of the transplant and the ischemic time were shorter than in the conventional grafting procedure. The virtual plan reduced the amount of bone removed to the required volume. The patients who underwent computer-assisted reconstruction had a higher degree of satisfaction with their outer appearance.

CONCLUSION

Our clinical experience and the collected data suggest that the described method is very promising for optimizing the surgical result of mandibular reconstructions using iliac crest bone grafts and achieving an excellent esthetic outcome.

LEVEL OF EVIDENCE IV

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