The Progress in Reconstruction of Mandibular Defect Caused by Osteoradionecrosis

Osteoradionecrosis (ORN) is described as a disease with exposed, nonviable bone that fails to heal spontaneously or by means of conservative treatment after radiotherapy in at least 3 months. Though traditional theories in the early stage including hypoxic-hypocellular-hypovascular and fibro-atrophic in addition to new findings such as ferroptosis were put forward to explain the mechanisms of the osteoradionecrosis, the etiology of ORN is still unclear. With the high rate of occurrence in the head and neck area, especially in the mandible, this disease can disrupt the shape and function of the irradiated area, leading to a clinical presentation ranging from stable small areas of asymptomatic exposed bone to severe progressive necrosis. In severe cases, patients may experience pain, xerostomia, dysphagia, facial fistulas, and even a jaw defect. Consequently, sequence therapy and sometimes extensive surgery and reconstructions are needed to manage these sequelae. Treatment options may include pain medication, antibiotics, the removal of sequesters, hyperbaric oxygen therapy, segmental resection of the mandible, and free flap reconstruction. Microanastomosed free-flaps are considered to be promising choice for ORN reconstruction in recent researches, and new methods including three-dimensional (3-D) printing, pentoxifylline, and amifostine are used nowadays in trying increase the success rates and improve quality of the reconstruction. This review summarizes the main research progress in osteoradionecrosis and reconstruction treatment of osteoradionecrosis with mandibular defect.

Review: cellularity in bone marrow autografts for bone and fracture healing

The use of autografts, as primary cell and tissue source, is the current gold standard approach to treat critical size bone defects and nonunion defects. The unique mixture of the autografts, containing bony compartments and bone marrow (BM), delivers promising results. Although BM mesenchymal stromal cells (BM-MSCs) still represent a major target for various healing approaches in current preclinical research and respective clinical trials, their occurrence in the human BM is typically low. In vitro expansion of this cell type is regulatory challenging as well as time and cost intensive. Compared with marginal percentages of resident BM-MSCs in BM, BM mononuclear cells (BM-MNCs) contained in BM aspirates, concentrates, and bone autografts represent a readily available abundant cell source, applicable within hours during surgical procedures without the need for time-consuming and regulatory challenging cell expansion. This benefit is one reason why autografting has become a clinical standard procedure. However, the exact anatomy and cellularity of BM-MNCs in humans, which is strongly correlated to their unique mode of action and wide application range remains to be elucidated. The aim of this review was to present an overview of the current knowledge on these specific cell types found in human BM, emphasize the contribution of BM-MNCs in bone healing, highlight donor site dependence, and discuss limitations in the current isolation and subsequent characterization procedures. Hereby, the most recent and relevant examples of human BM-MNC cell characterization, flow cytometric analyses, and findings are summarized, with a strong focus on bone therapy.

Mandibulectomy Reconstruction with Pectoralis Major Island Flap Associated with Primary Reconstruction Plate for Mandibular Medication-Related Osteonecrosis

A bimaxillary edentulous male patient, aged 67 years, diagnosed with prostate cancer who underwent intravenous bisphosphonates treatment (zoledronic acid) for about one year presented with pain in the anterior mandibular arch, with exposed necrotic bone, and was diagnosed with stage 2 medication-related osteonecrosis of the jaw (MRONJ). MRONJ is the development of bone necrosis in the oral cavity as an adverse reaction in patients treated with antiresorptive and antiangiogenic medication, without radiation therapy to the head and neck. This persistent bone necrosis does not always respond to standard treatments. The reconstruction technique with pectoralis major flap, at a distance, associated with the primary reconstruction plate, was an effective treatment modality for the treatment of large osteonecrosis noncompliant with conservatory treatments. Through this technique, the morpho-functionality of the jaw can be restored almost completely.

Reconstructive and prosthodontic outcomes after multiple palatomaxillary reconstructions

OBJECTIVE

A subset of patients who undergo major palatomaxillary reconstruction do not initially achieve their intended oncologic and/or reconstructive goals and require additional surgery. We aim to detail the unique management considerations in this patient population.

METHODS

We performed a retrospective review of patients who underwent palatomaxillary reconstruction by the senior author (m.l.u.) between 1998 and 2016.

RESULTS

Twenty-one patients required multiple reconstructions. The median time to second reconstruction was 17 months. The most common reason for a second reconstruction was for recurrent disease (10 of 21), followed by functional/aesthetic reasons (7 of 21) and osteoradionecrosis (4 of 21). Four patients went on to have a third reconstruction, and two underwent a fourth. A total of 27 reconstructions were performed, consisting of 20 soft tissue free flaps, four vascularized bone free flaps, and three locoregional flaps.

CONCLUSION

This patient cohort represents unique oncologic and reconstructive challenges. With long-term follow-up, multiple reconstructions may be required to optimize oncologic and functional/aesthetic outcomes. This is the first series of its kind that details the reasons for, as well as the outcomes of, patients who required multiple reconstructive procedures following initial palatomaxillary reconstruction.

LEVEL OF EVIDENCE

2B Laryngoscope, 130:2349-2353, 2020.

A case of effective oral rehabilitation after mandibular resection

Radical mandible resection causes significant functional and cosmetic impairment. Nonvascularized bone reconstruction and oral rehabilitation using fixed prosthesis with dental implants enabled recovery of appearance and mastication function.

Effect of Choukroun Platelet-Rich Fibrin Combined With Autologous Micro-Morselized Bone on the Repair of Mandibular Defects in Rabbits

PURPOSE

The aim of this study was to explore the effect of Choukroun platelet-rich fibrin (PRF) combined with autologous micro-morselized bone on the repair of mandibular defects in rabbits.

MATERIALS AND METHODS

Thirty-six healthy New Zealand rabbits were selected for the present study. After models of mandibular defects were established, rabbits were randomly divided into Choukroun PRF, autologous micro-morselized bone (autologous), Choukroun PRF combined with autologous bone (combined) and model groups. After the rabbits were sacrificed at 2, 8, and 12 weeks postoperatively, their bone formation was assessed by x-ray and scanning electron microscopy, and the histologic changes of the mandibular defect area were detected by hematoxylin and eosin staining. Cone-beam computed tomography was used to observe the size of the change of the mandibular defect area. Bone mineral density (BMD) was analyzed by dual-energy x-ray absorptiometry.

RESULTS

The bone defect in the combined group showed better repair, increased bone mineral content, and denser callus than the other groups, and the defect area was filled with mature trabecular bone. In the Choukroun PRF and autologous groups, the defect area was smaller and filled with osteoporotic trabecular bone. A clear mandibular defect area was still observed in the model group. Compared with the other groups, the combined group showed more bone regeneration, more fibrous tissue regeneration, and greater bone maturity at all time points. The combined group had the highest BMD, there was no relevant difference in BMD between the Choukroun PRF and autologous groups, and the model group had the lowest BMD. BMD in all 4 groups increased with time.

CONCLUSION

These findings indicate that Choukroun PRF combined with autologous micro-morselized bone can substantially improve the repair of mandibular defects in rabbits, and the effect is superior to Choukroun PRF or autologous micro-morselized bone alone.

Sectioned Images and Surface Models of a Cadaver for Understanding the Dorsalis Pedis Flap

The aim of this study was to represent the dorsalis pedis (DP) flap on sectioned images and surface models using Visible Korean for medical education and clinical training in the field of maxillofacial reconstructive surgery. Serially sectioned images of the foot were obtained from a cadaver. The important structures in the sectioned images were outlined and stacked to create a surface model. The PDF file (53 MB) of the assembled models is accessible for free download on the Department of Anatomy at Ajou University School of Medicine Web site (http://anatomy.co.kr). In this file, the significant anatomic structures of the DP flap can be inspected in the sectioned images. All surface models and stereoscopic structures of the DP flap are described in real time. We hope that these state-of-the-art sectioned images, outlined images, and surface models will help students and trainees gain a better understanding of the DP flap anatomy.

Mandibular reconstruction with autologous human bone marrow stem cells and autogenous bone graft in a patient with plexiform ameloblastoma

Ameloblastoma is a histologically benign tumor, but it shows a tendency of locally aggressive behavior. To our knowledge, this is the first report of a successful reconstruction performed for treating a mandibular defect by using autologous human bone marrow mesenchymal stem cells in a patient with plexiform ameloblastoma. In this article, we report the result of the mandibular reconstruction with autologous human bone marrow mesenchymal stem cells and autogenous bone graft, followed by the placement of osteointegrated dental implant and prosthodontic treatment in a patient with plexiform ameloblastoma.

Sectioned images and surface models of a cadaver for understanding the deep circumflex iliac artery flap

The aim of this study was to describe the deep circumflex iliac artery (DCIA) flap from sectioned images and stereoscopic anatomic models using Visible Korean, for the benefit of medical education and clinical training in the field of oromandibular reconstructive surgery. Serially sectioned images of the pelvic area were obtained from a cadaver. Outlines of significant structures in the sectioned images were drawn and stacked to build surface models. The PDF (portable document format) file (size, 30 MB) of the constructed models is available for free download on the Web site of the Department of Anatomy at Ajou University School of Medicine (http://anatomy.co.kr). In the PDF file, the relevant structures of the DCIA flap can be seen in the sectioned images. All surface models and stereoscopic structures associated with the DCIA flap are displayed in real time. We hope that these state-of-the-art sectioned images, outlined images, and surface models will help students and trainees better understand the anatomy associated with DCIA flap.

Outcome of microvascular free flaps in a high-volume training centre

PURPOSE

Microvascular free tissue transfer allows major ablative defects following oncologic surgical and traumatic reasons to be reliably reconstructed in the head and neck region. A retrospective analysis of the microvascular flap procedures which were performed within one year in a high volume training centre was performed.

PATIENTS AND METHODS

The microvascular free flap procedures of the year 2011 were reviewed and followed up until the 31st December 2012. The type and indication of the reconstructive procedure, operation time, operating team, experience and level of training of the surgeons involved, postoperative IMC (intermediate care unit) and/or ICU (intensive care unit) time, inpatient time, flap revisions, further postoperative complications, preoperative and postoperative radiation of the patients, the placement of dental implants were studied.

RESULTS

From 1st of January 2011 to 31st of December, 2011, the data of 101 patients with 103 microvascular free flap procedures were analysed of which 72% (84 flaps) were harvested by residents. The patients ranged in age from 14 to 89 years (mean age 59 years, 71 males and 40 females). The mean operation time was 591 min with the longest operation times for scapular flaps (744 min) and the shortest operation times for ALT flaps (455 min). Mean inpatient time was 34.2 days with a minimal time for the fibular flaps of 27.2 days and a maximum of 45.7 days for the latissimus dorsi flaps. 24 flaps (23.3%) in total had to be revised with bleeding being the main cause of immediate revisions (41.7% of all revisions). 5 flaps (4.85% of all flaps) were lost despite a revision procedure meaning a successful revision rate in 79.2% of all revisions.

CONCLUSION

Microvascular reconstruction procedures are safe and should be considered as standard procedures for reconstruction of large defects especially in high volume training centres. Intensive flap monitoring and early revisions maximize the flap outcome.

Outcomes of osseous free flap reconstruction in stage III bisphosphonate-related osteonecrosis of the jaw: systematic review and a new case series

INTRODUCTION

There is currently no gold standard for the treatment of Stage III bisphosphonate-related osteonecrosis of the jaw (BRONJ). The question remains whether osseous reconstruction can offer an additional gain in outcome given the theoretical risk of non-union at the resection margins and recurrence in the osseous free flap. The objective was to conduct a systematic review of articles describing outcomes of osseous microsurgical reconstruction in cases of BRONJ with a minimum follow-up of 12 months, and to present the long-term outcomes of a new case series of three patients.

MATERIAL AND METHODS

A multi-database QUORUM-based single-reviewer systematic review identified eight papers that fulfilled the selection criteria. There are only case series and case reports available (Level 4 of the Oxford Evidence-based medicine scale). A total of 31 patients were analysed including the cases described in this article.

CONCLUSION

The limited overall rate of non-union at the resection margins and the 6.5% recurrence rate of BRONJ in the transplant counters the theoretical objections and advocates for considering osseous free flap reconstruction in the treatment of refractory BRONJ Stage III lesions. However, additional data derived from larger case series or case-control studies are imperative to support this hypothesis.