The zygomatic arch is morphologically complex, providing a key interface between the viscerocranium and neurocranium. It also serves as an attachment site for masticatory muscles, thereby linking it to the feeding apparatus. Though morphological variation related to differential loading is well known for many craniomandibular elements, the adaptive osteogenic response of the zygomatic arch remains to be investigated. Here, experimental data are presented that address the naturalistic influence of masticatory loading on the postweaning development of the zygoma and other cranial elements. Given the similarity of bone-strain levels among the zygoma and maxillomandibular elements, a rabbit and pig model were used to test the hypothesis that variation in cortical bone formation and biomineralization along the zygomatic arch and masticatory structures are linked to increased stresses. It was also hypothesized that neurocranial structures would be minimally affected by varying loads. Rabbits and pigs were raised for 48 weeks and 8 weeks, respectively. In both experimental models, CT analyses indicated that elevated masticatory loading did not induce differences in cortical bone thickness of the zygomatic arch, though biomineralization was positively affected. Hypotheses were supported regarding bone formation for maxillomandibular and neurocranial elements. Varying osteogenic responses in the arch suggests that skeletal adaptation, and corresponding variation in performance, may reside differentially at one level of bony architecture. Thus, it is possible that phenotypic diversity in the mammalian zygoma is due more singularly to natural selection (vs. plasticity). These findings underscore the complexity of the zygomatic arch and, more generally, determinants of skull form.

Several articles support the use of cancellous iliac crest bone grafting in the treatment of clavicle nonunion; however, there is very little literature on the use of tricortical iliac crest grafts in the setting of clavicle nonunion with bone loss. When it has been studied, tricortical grafting has been shown to produce radiologically confirmed union in the clavicle, leaving patients satisfied with the ultimate outcome. We present two cases of clavicle fracture nonunion successfully treated with tricortical interposition bone grafting. In the first case, a 45-year-old female presented with an atrophic left midshaft clavicle fracture nonunion with failed hardware that had undergone two previous attempts at fixation without achieving union. She was treated with a structural interposition iliac crest bone graft with plate fixation and regained full painless function of the arm with radiographic fracture union. In the second case, a 50-year-old male presented after a left midshaft clavicle fracture that had undergone acute stabilization, followed by revision for nonunion that was unsuccessful, resulting in persistent nonunion with bone loss. He was treated with a tricortical iliac crest bone graft and plate fixation. Cultures from the time of surgery did grow Staphylococcus epidermidis and Propionibacterium acnes, and he was treated with intravenous vancomycin for six weeks. The patient’s clavicle went on to union and he regained full, painless function by his six-month follow-up visit. These cases demonstrate the use of tricortical interposition bone grafting with compression plating as a viable option for rare instances in which previous surgical intervention has failed to progress a midshaft clavicle fracture to union.

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Background: Incoming emergency medicine residents may feel unsure of their ability to handle common emergency department scenarios, even if they are well educated on the proper steps to take in those scenarios. This may not stem from a lack of skill so much as a lack of confidence in their ability to perform with skills they have. Objective: We look to establish a link between completion of simulationbased training in common emergency medicine scenarios and learner self-reported confidence in their ability to perform competently in those scenarios. Methods: Fourth-year medical students who matched into an emergency medicine residency program participated in a Transitional Educational Program (TEP) at the Interprofessional Immersive Simulation Center at the University of Toledo in April 2021. Simulations of 16 procedural skills and clinical judgement cases were carried out using high-fidelity mannequins and real medical equipment in a hospital-based setting. Subjects were given pre-and post-TEP survey questionnaires assessing their self-reported confidence to competently perform in common emergency medicine clinical scenarios, using a 5-grade Likert scale. Data was analyzed using a one-tailed Wilcoxon signed-rank matched-pairs test. Results: Of 19 participating subjects, 16 (84.2%) consented and responded to the pre-survey. Of those 16 subjects, 10 (62.5%) completed the surveys at the correct time and order. The pre-and post-surveys consisted of the same 14 questions. In 11 of 14 survey questions, there was a significant increase in subject self-reported confidence (p<.05) between pre-and post-survey. Conclusions: Simulation-based training in the setting of high-fidelity equipment and faculty guidance improved the self-reported confidence of incoming emergency medicine residents to perform in common emergency medicine scenarios.

Reverse total shoulder arthroplasty (rTSA) is typically indicated for severe glenohumeral disease with concomitant rotator cuff insufficiency, though sparse evidence suggests positive outcomes with its use in chronic shoulder dislocation as well. We present the case of a 51-year-old male with a chronic locked anterior glenohumeral dislocation for 7 months and associated rotator cuff tear, massive engaging Hill Sachs lesion, and Bankart lesion. Several attempts at both arthroscopic and open joint repair failed, and the patient was ultimately successfully treated with rTSA. The chronicity of this patient's dislocation and severity of concomitant articular defects put him at high risk of failing native joint repair, and while these operations were still attempted, the operative surgeon would recommend rTSA first if presented with this case again. The authors believe this case lends support to the use of rTSA as a primary operative intervention in patients with chronic locked glenohumeral dislocation, though further prospective research is needed to better support this recommendation.