Search

Zygomaticomaxillary complex fracture is one of the most commonly treated facial fractures. Accurate reduction and stable fixation of the zygoma are required to restore facial symmetry and projection and avoid functional sequalae from changes in orbital volume. Achieving optimal outcome is challenging due to the complex three-dimensional anatomy and limited visualization of all affected articulations of the zygoma. This article provides an updated overview of the evaluation and management of zygomaticomaxillary complex fractures based on available evidence and clinical experience at our center. The importance of soft tissue management is emphasized, and approaches to internal orbital reconstruction are discussed. While evidence remain limited, intraoperative imaging and navigation may prove to be useful adjuncts in the treatment of zygomaticomaxillary fractures.

Severe midface hypoplasia is often managed by Le Fort III distraction. Le Fort II distraction with zygomatic repositioning is a modification of the Le Fort III distraction operation aimed to correct abnormal facial ratios of patients with greater central than lateral midface deficiency. The operation starts with Le Fort III osteotomies and is followed by separation and fixation of bilateral zygomas. The central nasomaxillary Le Fort II segment is then distracted to achieve independent movements of the central and lateral midface. The Le Fort II zygomatic repositioning operation has become our procedure of choice for patients with Apert facial dysmorphology.

Background Tissue expansion in the pediatric population can be complicated by high rates of infection and extrusion. The aim of this study was to examine the impact of postoperative antibiotic prophylaxis on infectious complications. Methods A retrospective study of all pediatric patients who underwent tissue expander insertion at a children's hospital over a 12-year period was performed. Predictor variables included age, sex, race, indication, anatomical location, number of expanders inserted, serial expansion, history of infection or extrusion, and postoperative antibiotics. Outcome variables included infection and extrusion. Bivariate and multivariate analyses were performed to identify factors associated with infection and/or extrusion. Results A total of 180 patients who underwent 317 operations for tissue expander insertion were included in this study. Postoperative infection and/or extrusion occurred after 73 operations (23 percent). Postoperative prophylactic antibiotics were prescribed after 232 operations (75 percent), and only perioperative (≤24 hours) antibiotics were administered in 85 cases (25 percent). There were no significant differences in the rate of infection (12.1 percent versus 8.9 percent; p = 0.46), extrusion (16.8 percent versus 17.7 percent; p = 0.88), or infection and/or extrusion (23.7 percent versus 24.1 percent; p = 0.95) between these two groups. Multivariate analysis revealed that postoperative antibiotics did not have a significant association with infection and/or extrusion (OR, 0.84; 95 percent CI, 0.44 to 1.63; p = 0.61). Conclusions The rates of infection/extrusion were similar between pediatric patients who received only perioperative antibiotics (≤24 hours) and those who were prescribed a course of postoperative antibiotics. Based on these results, a course of postoperative prophylactic antibiotics may be unnecessary after insertion of tissue expanders in pediatric patients. Clinical question/level of evidence Therapeutic, III.

The purpose of this study was to compare the functional outcomes of different types of bilateral mandibular condylar fractures. This was a retrospective study of patients with bilateral mandibular condylar fractures at a level-1 trauma center over a 15-year period. The primary predictor variable was fracture pattern, classified as type I (bilateral condylar), type II (condylar–subcondylar), or type III (bilateral subcondylar). Secondary predictor variables were demographic, injury-related, and treatment factors. Bivariate associations between the predictors and complication rates were computed; a multiple logistic regression model was utilized to adjust for confounders and effect modifiers. Thirty-eight subjects with bilateral condylar injuries met the inclusion criteria. The sample's mean age was 37.6 + 18.2 years, and 16% were female. The most common mechanisms of injury were motor vehicle collisions (53%) and falls (29%). Seventy-four percent had associated noncondylar mandibular fractures, and 32% of cases had concomitant midface fractures. Fifty-three percent of cases were classified as type I, 21% as type II, and 26% as type III. Ten subjects (26%) were managed with open reduction and internal fixation. The average length of follow-up was 4.5 + 6.3 months. After adjusting for confounders and effect modifiers, the type of fracture was a significant predictor of functional complications with type II injuries having the highest likelihood of a poor functional outcome (odds ratio: 7.77, 95% confidence interval: 1.45–41.53, p = 0.02). Asymmetric bilateral mandibular condylar fractures may be associated with an increased risk of poor functional outcomes.

BACKGROUND Volumetric muscle loss secondary to traumatic or surgical causes can lead to functional and aesthetic impairments. The authors hypothesize that an implantable muscle-derived stem cell-enriched collagen scaffold could significantly augment muscle regeneration in a murine model of volumetric muscle loss. METHODS Murine muscle-derived stem cells were isolated using a modified preplating technique and seeded onto type 1 collagen scaffolds to create the muscle-derived stem cell-enriched collagen scaffolds. Murine rectus femoris defects of 5 mm were created and randomized to one of three conditions (n = 6 per group): untreated controls, collagen scaffold only, and muscle-derived stem cell-enriched collagen scaffolds. In vivo muscle healing was quantified using micro-computed tomography. Muscle explants were analyzed using standard histology and whole-mount immunofluorescence at 8 weeks. RESULTS In vivo experiments demonstrated significantly greater quadriceps cross-sectional area in the muscle-derived stem cell-enriched collagen scaffold group compared with controls on micro-computed tomography (0.74 ± 0.21 versus 0.55 ± 0.06 versus 0.49 ± 0.04 ratio of experimental to naive quadriceps cross-sectional area; p < 0.05). Muscle explants of the muscle-derived stem cell-enriched collagen scaffold group demonstrated significantly higher cellular density compared with controls (1185 ± 360 versus 359 ± 62 versus 197 ± 68 nuclei/high-power field; p < 0.01). Immunofluorescence for laminin and myosin heavy chain confirmed formation of organized muscle fibers within the defect of the muscle-derived stem cell-enriched collagen scaffold group only. However, appreciable confocal colocalization of myosin heavy chain with green fluorescent protein expression was low. CONCLUSIONS The results of this study indicate that muscle-derived stem cell-enriched scaffolds significantly improved skeletal muscle regeneration in a murine muscle defect model. Based on the low fluorescent colocalization, host progenitor cells appear to contribute significantly to intradefect myogenesis, suggesting that deployment of a viable muscle-derived stem cell-enriched scaffold stimulates a regenerative mitogen response in native tissues.

Anatomic studies have identified that patients with Treacher Collins syndrome and some cases of bilateral craniofacial microsomia are characterized by multilevel airway obstruction as a result of hypoplasia and clockwise rotation of the maxillomandibular complex. Patients often remain tracheostomy-dependent despite multiple airway surgeries. Counterclockwise craniofacial distraction osteogenesis aims to correct the facial skeletal deformity and expand the upper airway volume by rotating the subcranial complex en bloc around the nasofrontal junction. Early results have demonstrated significant increases in the nasopharyngeal and oropharyngeal airway volumes with successful decannulation in a majority of patients who have undergone this operation.

Background Tissue expansion is used for soft-tissue reconstruction in pediatric patients. The expansion process can be complicated by infection and extrusion, leading to premature expander removal. The aim of this study was to identify risk factors associated with premature expander removal caused by infection or extrusion in pediatric patients. Methods A retrospective study of pediatric patients who underwent tissue expansion performed by the senior author (R.J.R.) over a 12-year period was performed. Predictor variables included age, sex, race, indication, anatomical location, number of expanders, serial expansion, and expander size. Bivariate and multivariate analyses were performed to identify risk factors for premature expander removal. Results A total of 139 patients with 472 expanders were included in this study. Complications occurred with 78 expanders (16.5 percent). Premature expander removal caused by infection or exposure occurred with 51 expanders (10.8 percent). In terms of location, the highest rates of premature removal occurred in the lower extremity (20.0 percent) and scalp (16.3 percent). Multivariate analysis identified younger age (0 to 6 years compared with 13 to 17 years; OR, 3.98; 95 percent CI, 1.13 to 14.08; p = 0.03), greater number of expanders (OR, 1.45; 95 percent CI, 1.03 to 2.03; p = 0.03), and lower extremity location (OR, 4.27; 95 percent CI, 1.45 to 12.53; p = 0.008) were associated with an increased odds of premature expander removal. Conclusions Expander removal occurred in approximately 10 percent of tissue expanders. Odds of premature removal is increased with younger age, greater number of expanders, and lower extremity location. Clinical question/level of evidence Risk, III.

Fibrous dysplasia of bone (FD) is a mosaic disease caused by mutations in GNAS. Constitutive activation of the α-subunit of the Gs stimulatory protein (Gαs) leads to dysregulated proliferation of bone marrow stromal cells (BMSCs), generating expansile lesions of fibrotic tissue and abnormal bone. Local bone remodeling regulation by BMSCs is also altered, and FD tissue is characterized by abundant osteoclast-like cells that may be essential for lesion expansion. Animal models show local expression of RANKL in bone lesions, and treatment with the RANKL neutralizing antibody denosumab decreased lesion expansion rate in a patient with aggressive FD. However, the role of RANKL/osteoprotegerin (OPG) in FD pathophysiology is not yet understood. We measured serum levels of RANKL, OPG, and inactive RANKL-OPG complexes in FD patients of known disease burden and in healthy volunteers (HVs). RANK, RANKL, and Ki67 immunohistochemistry were assessed in FD tissue. Cultured FD and HV BMSCs were stimulated with prostaglandin E2 (PGE2 ) and 1,25 vitamin D3 to increase RANKL expression, and media levels of RANKL and OPG were measured. Osteoclastogenic induction by FD or HV BMSCs was assessed in co-cultures with HV peripheral monocytes. FD patients showed a 16-fold increase in serum RANKL compared to HVs. OPG was moderately increased (24%), although RANKL/OPG ratio was 12-fold higher in FD patients than in HVs. These measurements were positively correlated with the skeletal burden score (SBS), a validated marker of overall FD burden. No differences in serum inactive RANKL-OPG complexes were observed. In FD tissue, RANKL+ and Ki67+ fibroblastic cells were observed near RANK+ osteoclasts. High levels of RANKL were released by FD BMSCs cultures, but were undetectable in HV cultures. FD BMSC released less OPG than HV BMSCs. FD, but not HV BMSCs, induced osteoclastogenesis in monocyte co-cultures, which was prevented by denosumab addition. These data are consistent with the role of RANKL as a driver in FD-induced osteoclastogenesis. © 2018 American Society for Bone and Mineral Research.

Purpose Nonunion is an uncommon complication after mandibular fractures. The purpose of this investigation was to compare outcomes of patients with mandibular fracture nonunion who were treated with a 1- versus 2-stage approach and propose a pragmatic treatment algorithm for surgical management based on preoperative characteristics. Materials and Methods The authors conducted a retrospective study consisting of patients who presented to 2 level 1 trauma centers for the management of mandibular fracture nonunion over a 10-year period. The primary predictor variable was 1- versus 2-stage treatment. Outcomes were examined to propose a treatment algorithm. Results Eighteen patients were included in the study. The sample's mean age was 44.0 ± 19.3 years and most were men (88.9%). Mandibular angle and body accounted for 77.8% of cases. A single-stage approach was used in 13 patients (72.2%). Bone grafts or vascularized bone flaps were required in 13 patients (72.2%). Patients who required 2-stage treatments had intraoral soft tissue defects. Mean length of follow-up was 13.3 ± 20.4 months. All patients achieved bony union, with complications occurring in 5 patients (27.8%). The authors' 10-year experience was used to formulate a treatment algorithm based on bony defect size and soft tissue status, which can be used to inform optimal surgical management. Conclusions Nonunion of mandibular fractures is an infrequent and complex condition requiring careful and deliberate surgical management. A single-stage approach is appropriate in most cases and does not negatively affect outcomes. Bony defect size and soft tissue status are essential parameters for determining the approach and timing of reconstruction.

Candidates for vascularized composite allotransplantation (VCA) are frequently sensitized, putting them at risk for antibody-mediated rejection. Current desensitization strategies are imperfect and require a living-donor setting. Here we investigated the impact of sensitization on and the efficacy of a desensitization protocol utilizing syngeneic hematopoietic stem cell transplantation (HSCT) to prevent antibody-mediated rejection in VCA.Skin transplants from Dark Agouti to Lewis rats were performed for sensitization. Orthotopic hind limb transplants from Dark Agouti donors were performed to sensitized and nonsensitized recipients, and the animals were treated with either daily tacrolimus or no immunosuppression. A desensitization protocol consisting of total body irradiation, fludarabine, and syngeneic HSCT was applied to sensitized animals. Graft rejection was monitored by clinical assessment and histological analysis. Serum levels of donor-specific antibodies (DSA IgG) were measured using flow cytometry.Sensitized recipients exhibited accelerated rejection by 5.5 ± 1.2 days without immunosuppression and 10.2 ± 3.6 days with daily tacrolimus compared with 8.7 ± 1.2 days and longer than 30 days in nonsensitized recipients, respectively. Serum levels of DSA IgG were markedly elevated (37.3 ± 3.34-fold from baseline) in sensitized recipients after VCA and correlated with histologic evidence of rejection and C4d deposition. Desensitization significantly reduced DSA compared with sensitized controls (2.6 ± 0.5-fold vs 6.0 ± 1.2-fold, P0.01) and along with daily tacrolimus led to improved VCA survival longer than 30 days without evidence of C4d deposition (n = 6).In summary, sensitization leads to accelerated rejection of VCA, and syngeneic HSCT combined with conventional immunosuppression effectively reduces DSA and improves allograft survival in sensitized rats.

Orthognathic surgery describes the surgical movement of the mandible and maxilla to correct dentofacial deformities that result from congenital or traumatic etiologies. Patients with dentofacial deformity often have malocclusion and functional problems related to breathing, chewing, or speech articulation. Furthermore, facial asymmetries or disproportions resulting from dentofacial deformities can adversely affect the psychosocial health of the patient. The goal of orthognathic surgery is to improve both function and form beyond what can be achieved with orthodontic or medical treatments. Some of the most commonly performed orthognathic surgery procedures include Le Fort I osteotomy of the maxilla, bilateral sagittal split osteotomy of the mandible, and genioplasty. Successful outcome after orthognathic surgery should be judged by achieving an improved dental occlusion, enhanced facial aesthetics, and open upper airway. A number of studies have shown that orthognathic surgery leads to significant improvements in the quality of life of patients with dentofacial deformities. Orthognathic surgery also has a significant impact on the upper airway. In patients with severe obstructive sleep apnea, maxillomandibular advancement has the potential to lead to dramatic improvements in the apnea-hypopnea index and lowest oxygen saturation value. With careful surgical planning and execution, consistent outcomes can be expected. This review contains 17 figures, 4 tables, and 32 references. Key Words: aesthetic surgery, dentofacial deformity, genioplasty, Le Fort I, malocclusion, orthognathic surgery, sagittal split osteotomy of the mandible, sleep apnea, virtual surgical planning

This study investigates the efficacy of systemic growth hormone (GH) therapy in ameliorating the deleterious effects of chronic denervation (CD) injury on nerve regeneration and resulting motor function. Using a forelimb CD model, 4 groups of Lewis rats were examined (n = 8 per group): Group-1 (negative control) 8 weeks of median nerve CD followed by ulnar-to-median nerve transfer; Group-2 (experimental) 8 weeks of median nerve CD followed by ulnar-to-median nerve transfer and highly purified lyophilized pituitary porcine GH treatment (0.6 mg/day); Group-3 (positive control) immediate ulnar-to-median nerve transfer without CD; Group-4 (baseline) naïve controls. All animals underwent weekly grip strength testing and were sacrificed 14 weeks following nerve transfer for histomorphometric analysis of median nerve regeneration, flexor digitorum superficialis atrophy, and neuromuscular junction reinnervation. In comparison to untreated controls, GH-treated animals demonstrated enhanced median nerve regeneration as measured by axon density (p 2 vs 865.2 ± 48.33 µm2; p

Background Currently, there is a paucity of information on the presentation and proper management of pediatric nasoorbitoethmoid fractures. The purpose of this study was to examine the incidence, cause, associated injuries, and management of these fractures. Furthermore, the authors sought to assess outcomes after transnasal wiring or suture canthopexy for type III nasoorbitoethmoid fractures. Methods A retrospective cohort review was performed of all patients with nasoorbitoethmoid fractures who presented to a Level I trauma center from 1990 to 2010. Charts and computed tomographic imaging were reviewed, and nasoorbitoethmoid fractures were labeled based on the Markowitz-Manson classification system. Patient fracture patterns, demographics, characteristics, and outcomes were recorded. Univariate and multivariate methods were used to compare groups. Results A total of 63 pediatric patients were identified in the study period. The sample's mean age was 8.78 ± 4.08 years, and 28.6 percent were girls. The sample included 18 type I injuries, 28 type II injuries, and 17 type III injuries. No significant demographic differences were found between patients with type I, II, and III fractures (p > 0.05). Operative intervention was pursued in 16.7, 46.4, and 82.4 percent of type I, II, and III nasoorbitoethmoid fractures, respectively. In patients with type III nasoorbitoethmoid fractures, no patients with transnasal wiring developed telecanthus. Conclusions Pediatric nasoorbitoethmoid fractures are uncommon injuries. Type I fracture can often be treated with close observation. However, type II and III injury patterns should be evaluated for operative intervention. Transnasal wiring is an effective method to prevent traumatic telecanthus deformity in type III fracture patterns.

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.

BACKGROUND Previous work by our group and other laboratories have revealed that muscle-derived stem cells (MDSCs) may contain both myogenic and endothelial progenitors, making MDSCs a promising option for skeletal muscle regeneration. The purpose of this study was to investigate the impact of vascular endothelial growth factor (VEGF) induction on the vascular and myogenic potential of MDSCs. METHODS Muscle-derived stem cells were isolated from 4- to 8-week-old C57BL/6J mice using a preplate technique and recombinant human VEGFa was used as the induction agent. Cellular proliferation and migration were assessed using serial imaging and wound healing assays, respectively. Myosin heavy chain staining was performed to assess MDSC myotube formation. Vascular potential of MDSCs was measured by expression of CD31 and in vitro capillary tube formation. RESULTS Vascular endothelial growth factor stimulation led to a dose-dependent increase in MDSC proliferation (P < 0.05) and migration kinetics (P < 0.01). Control MDSCs had low levels of baseline expression of CD31, which was significantly upregulated by VEGF stimulation. Similarly, MDSCs demonstrated a basal capability for capillary tube formation, which was significantly increased after VEGF induction as evidenced by increased branches (5.91 ± 0.58 vs 9.23 ± 0.67, P < 0.01) and total tube length (11.73 ± 0.97 vs 18.62 ± 1.57 mm, P < 0.01). Additionally, the myogenic potential of MDSCs as measured by fusion index remained unchanged with increasing concentration of VEGF up to 250 ng/mL (P = 0.77). CONCLUSIONS Vascular endothelial growth factor induction enhances MDSC proliferation, migration, and endothelial phenotypes without negatively impacting myogenic potential. These results suggest that VEGF stimulation may improve vascularization of MDSC-based strategies for skeletal muscle regeneration.

Background Regeneration of functional bone substrate remains a priority in reconstructive surgery especially for patients suffering from complex skeletal defects. Efforts to develop implantable osteoinductive constructs and novel osteoconductive materials remain at the forefront of industry forces and product line development. Despite advancement in clinical practice and bone biology, cancellous autograft remains the gold standard for procedures requiring osteogenic mechanisms of healing. This study investigates the utility of muscle-derived stem cells as a cellular therapy for definitive bone regeneration through a form of neo-osteogenesis. Methods Adipose-derived stem cell, bone marrow-derived mesenchymal stem cell, and muscle-derived stem cell populations were isolated separately from C57BL/6 murine tissues and supplemented with collagen scaffolding with or without bone morphogenetic protein-2 to compare relative osteogenic potency and ultrastructure organization in both two- and three-dimensional systems. Parallel populations were bound to a deployable collagen implant within a syngeneic murine cranial defect model. Results Although all populations provided and maintained mesenchymal stem cell multilineage capacity, adipose-derived stem cell- and bone marrow-derived mesenchymal stem cell-enriched constructs were capable of forming small bone aggregates. Defects receiving muscle-derived stem cells self-assembled a form of organized corticocancellous structures within two- and three-dimensional in vitro systems and within the in vivo model. Muscle-derived stem cells also augmented healing, implant angiogenesis, and diploic space formation. Conclusion Muscle-derived stem cell-enriched implants appear to provide an autologous response to current industry-derived products and an attractive alternative to mesenchymal stem cells for the regeneration of corticocancellous bone and a vascularized diploic space.

BackgroundFunctional outcomes after vascularized composite allotransplantation (VCA) depend on nerve regeneration. After transplantation, the recipient peripheral nerve axons slowly grow and reinne...

BackgroundFunctional outcomes after vascularized composite allotransplantation (VCA) depend on nerve regeneration. After transplantation, the recipient peripheral nerve axons slowly grow and reinne...

Hyperthermia therapy has recently emerged as a clinical modality used to finely tune heat stress inside the human body for various biomedical applications. Nevertheless, little is known regarding the optimal timing or temperature of heat stress that is needed to achieve favorable results following hyperthermia therapy for muscle regeneration purposes. The regeneration of skeletal muscle after injury is a highly complex and coordinated process that involves a multitude of cellular mechanisms. The main objective of this study was to characterize the effects of hyperthermal therapy on the overall behavior of myoblasts during myogenic differentiation. Various cellular processes, including myogenesis, myofibrillogenesis, hypertrophy/atrophy, and mitochondrial biogenesis, were studied using systematic cellular, morphological, and pathway-focused high-throughput gene expression profiling analyses. We found that C2C12 myoblasts exhibited distinctive time and temperature-dependence in biosynthesis and regulatory events during myogenic differentiation. Specifically, we for the first time observed that moderate hyperthermia at 39°C favored the growth of sarcomere in myofibrils at the late stage of myogenesis, showing universal up-regulation of characteristic myofibril proteins. Characteristic myofibrillogenesis genes, including heavy polypeptide 1 myosin, heavy polypeptide 2 myosin, alpha 1 actin, nebulin and titin, were all significantly upregulated (p

BackgroundVascularized composite allotransplantation (VCA) is a promising option for patients with devastating injuries from severe burn or trauma The initial management of this patient population ...