Reconstruction of osteomyelitis defects of the craniofacial skeleton

Case Report: Reconstruction of a Large Maxillary Defect With an Engineered, Vascularized, Prefabricated Bone Graft

The reconstruction of complex midface defects is a challenging clinical scenario considering the high anatomical, functional, and aesthetic requirements. In this study, we proposed a surgical treatment to achieve improved oral rehabilitation and anatomical and functional reconstruction of a complex defect of the maxilla with a vascularized, engineered composite graft. The patient was a 39-year-old female, postoperative after left hemimaxillectomy for ameloblastic carcinoma in 2010 and tumor-free at the 5-year oncological follow-up. The left hemimaxillary defect was restored in a two-step approach. First, a composite graft was ectopically engineered using autologous stromal vascular fraction (SVF) cells seeded on an allogenic devitalized bone matrix. The resulting construct was further loaded with bone morphogenic protein-2 (BMP-2), wrapped within the latissimus dorsi muscle, and pedicled with an arteriovenous (AV) bundle. Subsequently, the prefabricated graft was orthotopically transferred into the defect site and revascularized through microvascular surgical techniques. The prefabricated graft contained vascularized bone tissue embedded within muscular tissue. Despite unexpected resorption, its orthotopic transfer enabled restoration of the orbital floor, separation of the oral and nasal cavities, and midface symmetry and allowed the patient to return to normal diet as well as to restore normal speech and swallowing function. These results remained stable for the entire follow-up period of 2 years. This clinical case demonstrates the safety and the feasibility of composite graft engineering for the treatment of complex maxillary defects. As compared to the current gold standard of autologous tissue transfer, this patient’s benefits included decreased donor site morbidity and improved oral rehabilitation. Bone resorption of the construct at the ectopic prefabrication site still needs to be further addressed to preserve the designed graft size and shape.

Craniofacial Bone Tissue Engineering: Current Approaches and Potential Therapy

Craniofacial bone defects can result from various disorders, including congenital malformations, tumor resection, infection, severe trauma, and accidents. Successfully regenerating cranial defects is an integral step to restore craniofacial function. However, challenges managing and controlling new bone tissue formation remain. Current advances in tissue engineering and regenerative medicine use innovative techniques to address these challenges. The use of biomaterials, stromal cells, and growth factors have demonstrated promising outcomes in vitro and in vivo. Natural and synthetic bone grafts combined with Mesenchymal Stromal Cells (MSCs) and growth factors have shown encouraging results in regenerating critical-size cranial defects. One of prevalent growth factors is Bone Morphogenetic Protein-2 (BMP-2). BMP-2 is defined as a gold standard growth factor that enhances new bone formation in vitro and in vivo. Recently, emerging evidence suggested that Megakaryocytes (MKs), induced by Thrombopoietin (TPO), show an increase in osteoblast proliferation in vitro and bone mass in vivo. Furthermore, a co-culture study shows mature MKs enhance MSC survival rate while maintaining their phenotype. Therefore, MKs can provide an insight as a potential therapy offering a safe and effective approach to regenerating critical-size cranial defects.

Challenges in Microsurgical Reconstruction for Craniofacial Osteomyelitis With Resultant Osteonecrosis

INTRODUCTION

Chronic osteomyelitis is characterized by compromised blood supply and eventual osteonecrosis. Definitive treatment requires aggressive resection of affected bone. The resultant defect poses a unique challenge to reconstructive surgeons. Much of the literature on craniofacial osteomyelitis focuses on infection eradication, rather than subsequent reconstruction. This article reports representative cases from our experience with free flap reconstruction for defects secondary to chronic osteomyelitis of the craniofacial skeleton.

METHODS/RESULTS

The authors selected 5 of the most difficult reconstructive cases of craniofacial osteomyelitis from our experience in a single tertiary referral institution with a follow-up of at least 6 months. Three of the 5 cases arose in the setting of previous head and neck cancer treated with resection and radiation therapy. One case had a previous surgical craniotomy complicated by osteomyelitis and multiple failed alloplastic reconstructions. The final case was due to multiple gunshots to the head, with subsequent cerebral and cranial abscess (>1000cc). In each case, the defect was successfully treated with free tissue transfer. Two cases required creation of recipient vessels with an arteriovenous loop.

CONCLUSIONS

Free tissue transfer provides a versatile and effective tool in the reconstruction of extensive craniofacial osteomyelitis defects. Furthermore, the addition of vascularized tissue can protect against further episodes of osteomyelitis. Finally, arteriovenous loops can be employed successfully when prior radiation and infection of the wound bed precludes the use of local recipient target vessels.

Reconstruction of chronic osteomyelitis of the nose using a thin latissimus dorsi perforator flap

Osteomyelitis is an acute or chronic inflammatory process that occurs in bone. Although cranial bones are rarely involved, timely diagnosis and early treatment are mandatory because of its proximity to critical neurovascular structures and aesthetic considerations.A 57-year-old woman, who had a comminuted open nasal bone fracture 20 years ago, presented a firm, painful swelling nose. Whole-body bone scan images indicated increased uptake of the nasal bone, which was suspected to be osteomyelitis. After debridement, the nose was reconstructed with a thin latissimus dorsi perforator flap.In this article, we report a rare case of chronic osteomyelitis of the nose and provide a brief review of the literature. It is important for clinicians to consider osteomyelitis for early diagnosis and treatment.