Benjamin D. Schultz

Classification of mandible defects and algorithm for microvascular reconstruction

Background: Composite mandibular tissue loss results in significant functional impairment and cosmetic deformity. This study classifies patterns of mandibular composite tissue loss and describes a microvascular treatment algorithm. Methods: A retrospective review of microvascular composite mandibular reconstruction from July of 2005 to April of 2013 by the senior surgeon at the R Adams Cowley Shock Trauma Center and at The Johns Hopkins Hospital yielded 24 patients with a mean follow-up of 17.9 months. Causes of composite mandibular defects included tumors, osteoradionecrosis, trauma, infection, and congenital deformity. Patients with composite tissue loss were classified according to missing subunits. Results: A treatment algorithm based on composite mandibular defects and microvascular reconstruction was developed and used to treat 24 patients. A type 1 defect is a unilateral dentoalveolar defect not crossing the midline and not extending into the angle of the mandible. A type 2 defect is a unilateral defect extending beyond the angle. A type 3 defect is a bilateral defect not involving the angles. A type 4 defect is a bilateral defect with extension into at least one angle. Type 2 defects were the predominant group. Patients had microvascular reconstruction using either fibula flaps (n = 19) or iliac crest flaps (n = 5). Complications included infection, partial necrosis, plate fracture, dehiscence, and microvascular thrombosis. Conclusion: This novel classification system and treatment algorithm allows for a consistent and reliable method of addressing composite mandibular defects and focuses on recipient vasculature and donor free flap characteristics. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Evolving Concepts of Skin and Mucosal Biopsy in Facial Vascularized Composite Allotransplantation

Facial vascularized composite allotransplantation has ushered in a new era in treating complex facial injuries that cannot be reconstructed using traditional techniques. Multiple teams have reported their experiences in monitoring for allograft rejection using skin and mucosal biopsies. The association of biopsy findings and clinical observations are poorly understood and are continuously being redefined. We review the world’s experience in monitoring skin and mucosal histological findings in facial transplantation, review acute rejection, antibody-mediated rejection, chronic rejection, and describe our institutional experience in the monitoring and management of facial allograft histology.

Extracapsular mandibular condyle fractures are associated with severe blunt internal carotid artery injury: Analysis of 605 patients

Background: Mandibular condyle fractures are common following facial trauma and carry an increased risk for concomitant blunt carotid artery injuries. Further elucidation of this relationship may improve vascular injury screening and management. Methods: A retrospective cohort study was performed for all patients sustaining condylar fractures presenting to a large trauma center over twelve years. Fracture locations were classified according to the Strasbourg Osteosynthesis Research Group (1, condylar head; 2, condylar neck; and 3, extracapsular condylar base). Carotid artery injury severity was based on the Biffl scale. Severe vascular injury was defined as a Biffl score greater than I. Results: 605 patients were identified with mandibular condyle fractures consisting of 21.0 percent (n = 127) condylar head; 26.8 percent (n = 162) condylar neck; and 52.2 percent (n = 316) extracapsular condylar base. The incidence of vascular injuries in this population was 5.5 percent (n = 33), of which 75.8 percent (n = 25) were severe. Severe vascular injuries occurred in 1.6 percent (n = 2) of condylar head, 2.5 percent (n = 4) of condylar neck, and 6.0 percent (n = 19) of extracapsular condylar base fractures (p < 0.05). Extracapsular condylar base fractures were independently associated with a 2.94-fold increased risk of a severe blunt carotid artery injury compared with other condyle fractures on multivariable analysis (p < 0.05). Conclusions: Extracapsular subcondylar fractures should heighten suspicion for concomitant blunt carotid artery injury. The data support a force transmission mechanism of injury in addition to direct injury from bony fragments. CLINICAL QUESTIONS/LEVEL OF EVIDENCE: Risk, II.

Large Animal Models for Vascularized Composite Allotransplantation

Large animal models have served as the foundation for clinical trials in all solid organ transplantation. Likewise, pre-clinical studies in vascularized composite allotransplantation (VCA) have provided a foundation for initial human applications in VCA. The growth of clinical VCA correspondingly benefits from large animal studies investigating the unique immunobiology, improved immunosuppressive regimens, and the potential induction of immunologic tolerance. VCA studies in large animal models of nonhuman primates, swine, and canines have and continue to build knowledge towards improved clinical outcomes.

Early Microchimerism After Face Transplantation Detected by Quantitative Real-time Polymerase Chain Reaction of Insertion/Deletion Polymorphisms.

V composite allografts (VCA), such as hand and face transplants, offer an alternative approach to complex reconstructive scenarios that otherwise require multiple complex operations. Multiple face transplants with various components of skin, muscle, and bone have been performed worldwide, with the most extensive including mandible and maxilla, tongue, and skin performed in 2012 at the University of Maryland Medical Center. Microchimerism, defined as the presence of low levels of donor-derived cells (<1%), has not been definitively associated with improved immunologic outcomes. We investigated the presence of chimerism in our clinical full-face VCA with upper and lower jaw vascularized bone marrow components using established techniques of flow cytometry and short tandem repeat analysis without detecting any evidence of macrochimerism. We subsequently analyzed postoperative whole blood samples from our face transplant recipient using a commercial assay (AlleleSEQR) that screens and quantifies DNA by quantitative polymerase chain reaction (PCR) using insertion/deletion (InDel) polymorphisms as genetic markers sensitive to 0.001%.

Chest Wall, Thymus, and Heart Vascularized Composite Allograft Proof of Concept Cadaveric Model for Heart Transplantation

AbstractThe use of vascularized composite allografts allows for the reconstruction of complex scenarios that previously have required multistaged operations. Heart transplantation often follows a series of previous operations leading to chest wall deformities and significant mediastinal adhesions that can limit the use of larger hearts, making it difficult to find a suitable donor. Further, research has shown that the use of vascularized bone marrow and vascularized thymus in transplantation potentially prolongs graft survival with decreased immunosuppression requirements. The authors propose using a vascularized composite allograft of the chest wall consisting of sternum and thymus in conjunction with the heart for cardiac transplantation to allow for more flexibility from the donor pool, maintain chest wall integrity and physiology, and potentially immunoregulate the concomitant solid organ transplant.

Which Factors Are Associated with Open Reduction of Adult Mandibular Condylar Injuries

Background: The purpose of this study was to identify factors associated with the decision to perform open reduction and internal fixation of mandibular condylar fractures. Methods: This was a retrospective cohort study of patients with mandibular condylar fractures managed by the plastic and reconstructive surgery, oral and maxillofacial surgery, and otorhinolaryngology services over a 15-year period. Bivariate associations and a multiple logistic regression model were computed for injury characteristics that were associated with open reduction and internal fixation. For all analyses, a value of p ⩽ 0.05 was considered significant. Results: Six hundred fifty-four condylar injuries were identified in 547 patients. The sample’s mean age was 36.0 ± 16.5 years, 20.5 percent were women, and 63 percent were Caucasian. The most common mechanisms of injury were motor vehicle collisions (49 percent), 53.4 percent involved the subcondylar region and 20 percent were bilateral injuries. Associated noncondylar mandibular fractures were present in 60 percent of cases; 20.7 percent were managed with open reduction and internal fixation. The overall complication rate was 21.6 percent. In a multiple logistic regression model, factors associated with an increased likelihood of open reduction and internal fixation were the presence of extracondylar mandibular injuries, condylar neck or subcondylar region injuries, increasing dislocation, and treatment by plastic and reconstructive surgery/oral and maxillofacial surgery (p ⩽ 0.04). Conclusions: Increasing severity of mandibular injury, lower level of fracture, joint dislocation, and treatment by plastic and reconstructive surgery/oral and maxillofacial surgery are associated with open reduction and internal fixation of mandibular condylar injuries. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.