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Isthmic spondylolysis is a common cause of back pain in young athletes. The condition presents to numerous medical providers who employ a variety of different practices in diagnosis and management. The purpose of this study was twofold: to review the literature of diagnosis and management of the young athlete with isthmic spondylolysis and to survey Pediatric Research in Sports Medicine (PRiSM) members during the 2021 PRiSM Annual Meeting on practice patterns of diagnosis and management of the young athlete with isthmic spondylolysis. The response rate was 27%. Per respondents: 24% obtain oblique radiographs; 90% use magnetic resonance imaging as the advanced imaging modality; 60% treat with bracing; 57% recommend rest prior to physical therapy (PT); 53% prescribe return to sport activity restrictions. Although there are similarities in the diagnosis of isthmic spondylolysis in young athletes, this survey confirmed variability in management, especially bracing, timing of PT and return to sport activity restrictions.

Background: The Pediatric Research in Sports Medicine (PRiSM) society is a multi-disciplinary group of healthcare providers who provide clinical care to young athletes with a variety of conditions, including isthmic spondylolysis. It is thought that significant practice differences exist in the way providers diagnose, image, and treat this condition. Hypothesis/Purpose: The purpose of this study is to survey the members of PRiSM on clinical practice patterns in the diagnosis, imaging, and management of isthmic spondylolysis in young athletes. Methods: An electronic, thirty-three question REDCaps survey was distributed to the PRISM membership via email during the 2021 virtual annual meeting and one reminder was sent after the meeting. Responses were collected during a 6-week period. The survey collected information based upon the following: demographics, diagnosis, imaging, and management. Results: Ninety-eight surveys were completed. Most of the respondents were divided between orthopaedic surgeons, non-operative sports medicine physicians and physical therapists, approximately half of which are fellowship trained. Approximately 42% of respondents make the diagnosis based upon MRI results in addition to history, physical examination, and plain radiographs. Approximately 24% obtain oblique radiographs as part of their assessment. MRI is the most frequently used advanced imaging modality with nearly 90% of respondents using this. The use of rigid bracing varies widely among respondents, with 20.6% bracing regularly, 35.3% sometimes bracing, and 44.1% not using rigid braces at all. The use of non-rigid bracing is similarly varied with 17.6% prescribing this regularly, 44.1% sometimes, and 38.2% not using non-rigid bracing at all. There is variance as well with regards to initiation of physical therapy (PT): prescribing immediately (42.6%) versus prescribing a period to rest prior to PT (57.4%). When young athletes are returned to sport, 52.9% of respondents indicated that they would impose restrictions to activity and 47.1% would not. Conclusion: Although there are similarities in how the diagnosis of isthmic spondylolysis in young athletes is made by PRISM members, there is variability in management, especially the use of bracing, the timing of physical therapy, and return to sport restrictions. MRI is the most common advanced imaging modality being used to help with the diagnosis.

Advances in the synthesis of materials and device structures have accentuated the need to understand nanoscale electronic structure and its implications. Scanning probe microscopy offers a rich variety of highly spatially accurate techniques that can further our understanding of the interactions that occur in nanoscale semiconductor materials and devices. The promising nitride semiconductor materials system suffers from perturbations in local electronic structure due to crystallographic defects. Understanding the electronic properties and physical origin of these defects can be invaluable in mitigating their impacts or eliminating them all together. In the second chapter of this dissertation, scanning capacitance microscopy (SCM) is used to characterize local electronic structure in a-plane n-type gallium nitride. Analysis reveals the presence of a linear, positively charged feature aligned along the direction which likely corresponds to a partial dislocation at the edge of a stacking fault. In the third chapter, conductive atomic force microscopy is used to determine the effects of Ga/N flux on the conductive behavior of reverse-bias leakage paths in gallium nitride grown by molecular beam epitaxy (MBE). Our data reveal a band of fluxes near Ga/N ̃ ̃1 for which these pathways cease to be observable. These observations suggest a method for controlling the primary source of reverse-bias Schottky contact leakage in n-type GaN grown by MBE. A deeper understanding of the interaction between macro-scale objects and nanoscale electronic properties is required to bring the exciting new possibilities that semiconductor nanowires offer to fruition. In the fourth chapter, SCM is used to examine the effects of micron-scale metal contacts on carrier modulation and electrostatic behavior in indium arsenide semiconductor nanowires. We interpret a pronounced dependence of capacitance spectra on distance between the probe tip and nanowire contact as a consequence of electrostatic screening of the tip-nanowire potential difference by the large metal contact. These results provide direct experimental verification of contact screening effects on the electronic behavior of nanowire devices and are indicative of the importance of accounting for the effect of large-scale contact and circuit elements on the characteristics of nanoscale electronic devices