Notch is a cell–cell signaling pathway that is involved in a host of activities including development, oncogenesis, skeletal homeostasis, and much more. More specifically, recent research has demonstrated the importance of Notch signaling in osteogenic differentiation, bone healing, and in the development of the skeleton. The craniofacial skeleton is complex and understanding its development has remained an important focus in biology. In this review we briefly summarize what recent research has revealed about Notch signaling and the current understanding of how the skeleton, skull, and face develop. We then discuss the crucial role that Notch plays in both craniofacial development and the skeletal system, and what importance it may play in the future.

Biomechanical and clinical studies have yet to converge on the optimal fixation technique for angle fractures, one of the most common and controversial fractures in terms of fixation approach. Prior pre-clinical studies have used a variety of animal models and shown abnormal strain environments exacerbated by less rigid (single-plate) Champy fixation and chewing on the side opposite the fracture (contralateral chewing). However, morphological differences between species warrant further investigation to ensure that these findings are translational. Here we present the first study to use realistically loaded finite-element models to compare the biomechanical behaviour of human and macaque mandibles pre- and post-fracture and fixation. Our results reveal only small differences in deformation and strain regimes between human and macaque mandibles. In the human model, more rigid biplanar fixation better approximated physiologically healthy global bone strains and moments around the mandible, and also resulted in less interfragmentary strain than less rigid Champy fixation. Contralateral chewing exacerbated deviations in strain, moments and interfragmentary strain, especially under Champy fixation. Our pre- and post-fracture fixation findings are congruent with those from macaques, confirming that rhesus macaques are excellent animal models for biomedical research into mandibular fixation. Furthermore, these findings strengthen the case for rigid biplanar fixation over less rigid one-plate fixation in the treatment of isolated mandibular angle fractures.

Introduction The objectives of this study were to identify factors associated with nonattendance to follow-up in patients seen for traumatic hand and facial injuries at an urban Level 1 trauma center and to elucidate patient-reported reasons for nonattendance. Methods A retrospective chart review was performed for all patients seen for hand and facial trauma at our institution over a 2-year period. Demographic data, including race, insurance status, and incomes based on zip code data, were collected for all patients. Injury patterns, interventions, and patient disposition were analyzed. A binomial multivariate logistic regression was conducted to identify predictors of nonattendance to follow-up. All patients who were lost to follow-up over the last 12-month period were contacted via phone to identify reasons for nonattendance to determine whether they had followed up with another provider and to analyze long-term injury sequelae. Results After exclusion criteria were applied, there were 889 patients included in the analysis, with 31% of patients lost to follow-up. Factors significantly associated with follow-up nonattendance included patients who sustained injuries from gunshot wounds or assault, had no insurance or were out of network, and who received no acute intervention for their injuries. Forearm, wrist, and fingers fractures; facial fractures and lacerations; performing a procedure in the ED or operating room; and commercial insurance were all independent predictors of clinic attendance. The most common reasons for nonattendance cited by patients were “did not feel the need” (28%), lack of transportation (20%), and scheduling conflicts (19%). Conclusions Clinic follow-up for patients sustaining hand and facial trauma at a Level 1 trauma center is impacted by the socioeconomic factors that make this patient population particularly vulnerable to injury.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis (SJS/TEN) are life-threatening conditions best approached with multidisciplinary burn-equivalent care. There is a lack of consensus on wound management, in particular whether to debride detached epidermis. Our center instituted “antishear” wound therapy thirty-five years ago, where detached skin is left in situ as a biologic dressing and a standardized protocol avoids shear forces to prevent further desquamation. Our center’s initial results showed outcomes comparable to SCORTEN predictions, but advancements in burn critical care necessitate a re-evaluation of the antishear approach. A retrospective chart review was conducted for all patients admitted between 06/2004 to 05/2020 with a dermatologist-confirmed diagnosis of SJS/TEN (N=51). All patients were treated with burn-equivalent critical care and antishear wound therapy. Standardized mortality ratios were calculated using the established SCORTEN, and newly developed ABCD-10, prediction models. Mean SCORTEN, ABCD-10, and %TBSA were 2.6, 2.0, and 28%. Overall mortality was 22%; SCORTEN score (p<0.001), ABCD-10 score (p<0.01), %TBSA involved (p=0.02), and development of multi-system organ failure (p<0.001) correlated with increased mortality. Cohort-wide standardized mortality based on ABCD-10 was 1.18 (p=0.79). Standardized mortality based on SCORTEN was 0.62 (p=0.20) and 0.77 (p=0.15) for patients with scores ≤3 and >3; across the cohort it was 0.71 (p=0.11), representing a 29% mortality reduction. Incorporating the antishear approach as part of burn-equivalent care for SJS/TENS led to outcomes comparable to those predicted for surgical debridement via SCORTEN. However, the antishear approach has the advantage of avoiding painful dressing changes, sedation, and general anesthesia required for surgical debridement.

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