The dynamics of firm growth and failure under alternative forms of ownership.

This thesis extends the literature on the dynamics of firm growth and failure by testing the robustness of past findings for capitalist firms to alternative ownership structures. While the theoretical results are altered by the internal organisation of the firm, the empirical findings are unchanged. This suggests that the theoretical models place excessive emphasis on the organisational structure and inadequate emphasis on more basic and fundamental factors affecting firm growth. The thesis applies the learning models of growth to the case of the Illyrian labour managed firm, where members maximise profits per worker. The critical efficiency-size relationship is indeterminate under labour management. Thus, the majority of the clear cut empirical predictions of the model for profit maximisation no longer hold. Three possible explanations for the breakdown of the results are examined. One explanation is that the Illyrian model is overly simplistic and does not accurately reflect the actual behaviour of cooperatives. This is rejected using an institutional structure model of the French producer cooperative which yields predictions which are remarkably similar to those of the Illyrian model. The second explanation considered is that the growth and survival of cooperatives in fact substantially differs from capitalist firms. This explanation is rejected in the empirical section which tests the actual growth and survival relationships using a dataset of French producer cooperatives. The estimated survival-size relation is convexly positive and the growth-size relation convexly negative, exactly as they have been found previously for conventional firms. The final remaining explanation is that the theoretical models are structured so as to overemphasize the internal structure of the firm to the neglect of more generic factors affecting growth and survival. This is accepted in a final section which proposes new directions for theoretical research on the growth and survival of all firms

Effectiveness of combined magnetic field bone growth stimulation on lumbar spinal fusion outcomes: a single center retrospective analysis comparing combined magnetic field to no-stimulation

Background: The objective of this retrospective study was to assess the effect of combined magnetic field (CMF) bone growth stimulation on lumbar fusion outcomes, as compared to no-stimulation.Methods: This study reviewed fusion efficacy of a consecutive cohort of 652 patients who underwent lumbar fusion surgery at our institution between 2001 and 2018.  Fusion status was determined via radiographic analysis, with four surgeons contributing data to this study. The minimum patient follow-up time was 6 months. Previously identified risk factors (i.e. smoking status) were also collected. Statistical analysis was performed using cross-tabulation tests with chi-square analyses, one-way ANOVA’s, and Tukey’s range tests. 53% (343/652) of patients had undergone adjuvant treatment with CMF stimulation.Results: Patients treated with CMF stimulation had significantly greater fusion success of 97% compared to no stimulation at 62% (p<0.00001). Further, it was observed that smokers had a significantly higher fusion rate with CMF treatment than without electrical stimulation (94% vs 61%, p=0.000032).Conclusions: Additional studies to evaluate the effectiveness of CMF treatment in patients with risk factors are warranted

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Factors impacting adherence to an exercise-based physical therapy program for individuals with low back pain

Background/objectiveExercise-based rehabilitation is a conservative management approach for individuals with low back pain. However, adherence rates for conservative management are often low and the reasons for this are not well described. The objective of this study was to evaluate predictors of adherence and patient-reported reasons for non-adherence after ceasing a supervised exercise-based rehabilitation program in individuals with low back pain.DesignRetrospective observational study.MethodsData was retrospectively analyzed from 5 rehabilitation clinics utilizing a standardized exercise-based rehabilitation program. Baseline demographics, diagnosis and symptom specific features, visit number, and discontinuation profiles were quantified for 2,243 patients who underwent the program.ResultsForty-three percent (43%) of participants were adherent to the program, with the majority (31.7%) discontinuing treatment prior to completion due to logistic and accessibility issues. Another 13.2% discontinued prior to the prescribed duration due to clinically significant improvements in pain and/or disability without formal discharge evaluation, whereas 8.3% did not continue due to lack of improvement. Finally, 6.0% were discharged for related and unrelated medical reasons including surgery. Individuals diagnosed with disc pathology were most likely to be adherent to the program.LimitationsThis study was a retrospective chart review with missing data for some variables. Future studies with a prospective design would increase quality of evidence.ConclusionsThe majority of individuals prescribed an in-clinic exercise-based rehabilitation program are non-adherent. Patient diagnosis was the most important predictor of adherence. For those who were not adherent, important barriers include personal issues, insufficient insurance authorization and lack of geographic accessibility