Study Design: This is a retrospective analysis of kinematic magnetic resonance images (kMRI). Objective: To assess the association of cervical paraspinal muscle with cervical sagittal balance and degenerative spinal disorders. Summary of Background Data: Although the effects of spinal disorders and cervical imbalance on patient’s symptoms have been well described, the relationship of the cervical muscle quality and volume to cervical imbalance or spinal disorders is not well established. Materials and Methods: In total, 100 kMRI taken in a neutral weight-bearing position were analyzed. The adjusted cross-sectional area ratio (aCSA ratio: the value of muscle CSA divided by the vertebral CSA) and fat infiltration ratio of the transversospinalis muscles at C4 and C7 vertebral levels were measured using axial slice of kMRI. The correlation with cervical balance parameters [Oc–C2 angle, C2–C7 angle, C7–T1 angle, C7 slope, T1 slope, cranial tilt, cervical tilt, thoracic inlet angle (TIA), and neck tilt] and cervical degenerative disorders (disk degeneration, Modic change, and spondylolisthesis) were evaluated. Results: The aCSA ratio at C4 correlated with C2–C7 angle (r=0.267), C7 slope (r=0.207), T1 slope (r=0.221), disk degeneration at C3–4, C4–5, C5–6 (r=−0.234, −0.313, −0.262) and spondylolisthesis at C3 (anterior: r=−0.206, posterior: r=−0.249). The aCSA ratio at C7 correlated with disk degeneration at C3–4, C4–5, C5–6, C6–7 (r=−0.209, −0.294, −0.239, −0.209). The fat infiltration ratio at C4 correlated with TIA (r=0.306) and neck tilt (r=0.353), likewise the ratio at C7 correlated with TIA (r=0.270) and neck tilt (r=0.405). All correlations above were statistically significant with P<0.05. Conclusions: The paraspinal muscle volume showed significant relationship with the cervical balance parameters and disk degeneration. While, paraspinal muscle quality related to the thoracic inlet parameters. Our findings can be an important step to develop the knowledge of the association between cervical muscle and cervical degenerative disorders, as well as the sagittal balance of the cervical spine. Level of Evidence: Level III.

Improving microbial fuel cell (MFC) performance continues to be the subject of research, yet the role of operating conditions, specifically duty cycling, on MFC performance has been modestly addressed. We present a series of studies in which we use a 15-anode environmental MFC to explore how duty cycling (variations in the time an anode is connected) influences cumulative charge, current, and microbial composition. The data reveal particular switching intervals that result in the greatest time-normalized current. When disconnection times are sufficiently short, there is a striking decrease in current due to an increase in the overall electrode reaction resistance. This was observed over a number of whole cell potentials. Based on these results, we posit that replenishment of depleted electron donors within the biofilm and surrounding diffusion layer is necessary for maximum charge transfer, and that proton flux may be not limiting in the highly buffered aqueous phases that are common among environmental MFCs. Surprisingly, microbial diversity analyses found no discernible difference in gross community composition among duty cycling treatments, suggesting that duty cycling itself has little or no effect. Such duty cycling experiments are valuable in determining which factors govern performance of bioelectrochemical systems and might also be used to optimize field-deployed systems.

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Background Medial clavicle fractures are uncommon, occurring in older and multiply injured patients. The management of these fractures and the factors that predispose toward poor outcomes are controversial. Furthermore, the functional outcomes of treatment are not well characterized or correlated with fracture patterns. Questions/purposes (1) To determine minimum 1-year functional outcomes using QuickDASH scores and pain scores after medial clavicle fractures and (2) to identify factors associated with these outcome variables. Methods In an institutional review board–approved, retrospective study, we identified adult patients with medial clavicle fractures at two tertiary care referral centers in a single metropolitan area in the United States from January 2010 to March 2019. Our initial query identified 1950 patients with clavicle fractures, from which 74 adult patients with medial clavicle fractures and at least 1 year of follow-up were identified. We attempted to contact these eligible patients by telephone for functional outcomes and pain scores. Twenty-six patients were deceased according to the most recent Social Security Death Index data and public obituaries, three declined participation, and 14 could not be reached, leaving 42% of the total (31 of 74) and 65% (31 of 48) of living patients included in the analysis. Demographic characteristics, fracture characteristics, and clinical and radiographic union as assessed by plain radiography and CT were collected through record review. Twenty-nine patients were treated nonoperatively and two patients underwent open reduction internal fixation. Sixty-eight percent (21 of 31) of the included patients also had radiographic follow-up at least 6 weeks postoperatively; two patients had persistent nonunion at a mean of 5 ± 3 years after injury. Our primary response variable was the QuickDASH score at a minimum of 1 year (median [range] 5 years [2 to 10]). Our secondary response variable was the pain score on a 10-point Likert scale. A bivariate analysis was performed to identify factors associated with these response variables. The following explanatory variables were studied: age, gender, race, dominant hand injury, employment status, manual labor occupation, primary health insurance, social deprivation, BMI, diabetes mellitus, smoking status, American Society of Anesthesiologists physical status classification, Charlson Comorbidity Index, nonisolated injury, high-energy mechanism of injury, nondisplaced fracture, fracture comminution, superior-inferior fracture displacement, medial-lateral fracture shortening, and surgical treatment of the medial clavicle fracture. Results The mean QuickDASH score was 12 ± 15, and the mean pain score was 1 ± 1 at a mean of 5 ± 3 years after injury. The mortality rate of the cohort was 15% (11 of 74) at 1 year, 22% (16 of 74) at 3 years, and 34% (25 of 74) at 5 years after injury. With the numbers available, no factors were associated with the QuickDASH score or pain score, but it is likely we were underpowered to detect potentially important differences. Conclusion Medial clavicle fractures have favorable functional outcomes and pain relief at minimum 1-year follow-up among those patients who survive the trauma, but a high proportion will die within 3 years of the injury. This likely reflects both the frailty of a predominantly older patient population and the fact that these often are high-energy injuries. The outcome measures in our cohort were not associated with fracture displacement, shortening, or comminution; however, our sample size was underpowered on these points, and so these findings should be considered preliminary. Further studies are needed to determine the subset of patients with this injury who would benefit from surgical intervention. Level of Evidence Level IV, therapeutic study.

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