Biomaterials-aided mandibular reconstruction using in vivo bioreactors.

Large mandibular defects are clinically challenging to reconstruct due to the complex anatomy of the jaw and the limited availability of appropriate tissue for repair. We envision leveraging current advances in fabrication and biomaterials to create implantable devices that generate bone within the patients themselves suitable for their own specific anatomical pathology. The in vivo bioreactor strategy facilitates the generation of large autologous vascularized bony tissue of customized geometry without the addition of exogenous growth factors or cells. To translate this technology, we investigated its success in reconstructing a mandibular defect of physiologically relevant size in sheep. We fabricated and implanted 3D-printed in vivo bioreactors against rib periosteum and utilized biomaterial-based space maintenance to preserve the native anatomical mandibular structure in the defect site before reconstruction. Nine weeks after bioreactor implantation, the ovine mandibles were repaired with the autologous bony tissue generated from the in vivo bioreactors. We evaluated tissues generated in bioreactors by radiographic, histological, mechanical, and biomolecular assays and repaired mandibles by radiographic and histological assays. Biomaterial-aided mandibular reconstruction was successful in a large superior marginal defect in five of six (83%) sheep. Given that these studies utilized clinically available biomaterials, such as bone cement and ceramic particles, this strategy is designed for rapid human translation to improve outcomes in patients with large mandibular defects.

Massive Self-Induced Subcutaneous Cervicofacial, Pneumomediastinum, and Pneumopericardium Emphysema Sequelae to a Nondisplaced Maxillary Wall Fracture: A Case Report and Literature Review.

Iatrogenic cervicofacial subcutaneous emphysema is a well-reported entity in the field of dentistry and oral and maxillofacial surgery, especially with the use of air-driven headpieces. Cervicofacial subcutaneous emphysema sequelae after maxillofacial trauma, however, has been reported less and the self-induced variant is even rarer. We report a case of massive cervicofacial subcutaneous emphysema, pneumomediastinum, and pneumopericardium in a healthy 16-year-old boy after blunt trauma to the face, which caused a nondisplaced anterior maxillary wall fracture. The findings from the present case report will validate the common phrase "no nose blowing or holding your sneezes" that clinicians tell patients after maxillofacial trauma and sinus surgery.

Immediate Transoral Allogeneic Bone Grafting for Large Mandibular Defects. Less Morbidity, More Bone. A Paradigm in Benign Tumor Mandibular Reconstruction?

PURPOSE: Reconstruction of hard tissue continuity defects caused by ablative tumor surgery has been traditionally reconstructed with autogenous bone grafts or microvascular free flaps. Although results have been predictable from these 2 methods of reconstruction, the morbidity associated with bone harvest is quite serious for the patient. Predictable results have been obtained with using a combination of 100% cadaver bone, bone marrow aspirate concentrate (BMAC), and recombinant human bone morphogenic protein in immediate reconstruction for benign tumor extirpations through the extraoral approach. In light of these successful outcomes, the same combination was evaluated with an intraoral approach. This study evaluated the success of immediate mandibular reconstruction through the intraoral approach without any autogenous bone harvesting. PATIENTS AND METHODS: The aim of this retrospective study was to share the authors' experience with the use of 100% allogeneic bone in combination with bone morphogenic protein and BMAC through the transoral approach for immediate reconstruction of continuity defects that resulted from benign tumor surgery. A retrospective chart review was performed of all patients undergoing bone graft reconstruction at the University of Texas Health Sciences Center at Houston (UTHealth) Department of Oral and Maxillofacial Surgery from December 2014 through January 2016. Inclusion criteria were biopsy-proven benign tumors, American Society of Anesthesiologists I or II health status, and adequate intraoral soft tissue for primary closure determined during initial consultation. RESULTS: Five patients who underwent this procedure at the UTHealth Department of Oral and Maxillofacial Surgery from December 2014 through January 2016 are presented. The success rate was 100%. All patients showed excellent bone quality clinically and radiographically for endosseous dental implant placement. With the transoral approach and no autogenous bone harvesting, the average operating time was 3.4 hours and the hospital stay was 2.4 days. CONCLUSIONS: Composite allogeneic tissue engineering is an effective and predictable technique for immediate reconstruction of continuity defects from ablative benign tumor surgery. Overall, there was no donor site morbidity, the intraoperative time was shorter, there were fewer admission days, and total costs overall were lower compared with traditional methods.

Repair of complex ovine segmental mandibulectomy utilizing customized tissue engineered bony flaps.

Craniofacial defects require a treatment approach that provides both robust tissues to withstand the forces of mastication and high geometric fidelity that allows restoration of facial architecture. When the surrounding soft tissue is compromised either through lack of quantity (insufficient soft tissue to enclose a graft) or quality (insufficient vascularity or inducible cells), a vascularized construct is needed for reconstruction. Tissue engineering using customized 3D printed bioreactors enables the generation of mechanically robust, vascularized bony tissues of the desired geometry. While this approach has been shown to be effective when utilized for reconstruction of non-load bearing ovine angular defects and partial segmental defects, the two-stage approach to mandibular reconstruction requires testing in a large, load-bearing defect. In this study, 5 sheep underwent bioreactor implantation and the creation of a load-bearing mandibular defect. Two bioreactor geometries were tested: a larger complex bioreactor with a central groove, and a smaller rectangular bioreactor that were filled with a mix of xenograft and autograft (initial bone volume/total volume BV/TV of 31.8 ± 1.6%). At transfer, the tissues generated within large and small bioreactors were composed of a mix of lamellar and woven bone and had BV/TV of 55.3 ± 2.6% and 59.2 ± 6.3%, respectively. After transfer of the large bioreactors to the mandibular defect, the bioreactor tissues continued to remodel, reaching a final BV/TV of 64.5 ± 6.2%. Despite recalcitrant infections, viable osteoblasts were seen within the transferred tissues to the mandibular site at the end of the study, suggesting that a vascularized customized bony flap is a potentially effective reconstructive strategy when combined with an optimal stabilization strategy and local antibiotic delivery prior to development of a deep-seated infection.

Localized mandibular infection affects remote in vivo bioreactor bone generation.

Mandibular reconstruction requires functional and aesthetic repair and is further complicated by contamination from oral and skin flora. Antibiotic-releasing porous space maintainers have been developed for the local release of vancomycin and to promote soft tissue attachment. In this study, mandibular defects in six sheep were inoculated with 106 colony forming units of Staphylococcus aureus; three sheep were implanted with unloaded porous space maintainers and three sheep were implanted with vancomycin-loaded space maintainers within the defect site. During the same surgery, 3D-printed in vivo bioreactors containing autograft or xenograft were implanted adjacent to rib periosteum. After 9 weeks, animals were euthanized, and tissues were analyzed. Antibiotic-loaded space maintainers were able to prevent dehiscence of soft tissue overlying the space maintainer, reduce local inflammatory cells, eliminate the persistence of pathogens, and prevent the increase in mandibular size compared to unloaded space maintainers in this sheep model. Animals with an untreated mandibular infection formed bony tissues with greater density and maturity within the distal bioreactors. Additionally, tissues grown in autograft-filled bioreactors had higher compressive moduli and higher maximum screw pull-out forces than xenograft-filled bioreactors. In summary, we demonstrated that antibiotic-releasing space maintainers are an innovative approach to preserve a robust soft tissue pocket while clearing infection, and that local infections can increase local and remote bone growth.

A technique for the treatment of oral-antral fistulas resulting from medication-related osteonecrosis of the maxilla: the combined buccal fat pad flap and radical sinusotomy.

OBJECTIVE: Bisphosphonates and monoclonal antibodies directed at osteoclastic function are frequently used to treat postmenopausal and corticosteroid-induced osteoporosis. They are also used in the treatment of certain metastatic malignancies. However, osteonecrosis of the jaw has been reported after intravenous, subcutaneous, or oral use of these agents. More than 12 million Americans and another 20 million worldwide are thought to be taking a bisphosphonate. Exposed bone with oral-antral fistulas has been known to occur increasingly as a specific presentation of what is now termed medication-related osteonecrosis of the jaws (MRONJ) with a specific International Classification of Diseases, 10th revision (ICD-10) code. Oral-antral communications caused by bisphosphonate concomitant with secondary sinusitis represent a unique treatment challenge for the oral and maxillofacial surgeon. The purpose of this article is to demonstrate a simple but effective technique to treat oral-antral communications caused by MRONJ. STUDY DESIGN: With the review and approval of the University of Miami Internal Review Board, we identified 23 patients who had undergone this surgical procedure. RESULTS: We report a 100% resolution of osteonecrosis of the jaw (ONJ) and sinusitis with repneumatization. CONCLUSIONS: The buccal fat pad and radical sinustomy can be used as an effective and predictable technique for the resolution of oral-antral fistulas caused by MRONJ.

Case Report of Multiple Tracheostomy Revisions due to Persistent, Recurrent Cuff Leak.

This case is a patient with amyotrophic lateral sclerosis who was unable to be separated from mechanical ventilator support and required a tracheostomy. The patient underwent an initial open tracheostomy utilizing flexible fiberoptic tracheoscopy (FFT) in the operating room (OR). Subsequently, he developed recurrent leaks in the tracheal tube cuff requiring multiple trips back to the operating room. The recurrent cuff leak occurred following each tube placement until the etiology of the leak was discovered during the fourth procedure. In the fourth procedure, the wound was explored more extensively, and it was found that there was a sharp, calcified, aberrant fragment of a tracheal cartilage ring protruding into the tracheal lumen, which was damaging the cuff of each tube. This fragment was not visible by multiple FFTs, nor was it visible in the wound by the surgeons until wider exploration of the wound occurred. The cartilage fragment was ultimately excised and the patient had no further cuff leaks. Aberrant tracheal cartilage should be on the differential diagnosis for cuff leaks subsequent to surgical tracheostomy (ST) or percutaneous dilatational tracheostomy (PDT).