Thomáy-Claire Ayala Hoelen

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that develops during adolescence in otherwise healthy individuals. Although traditional care has focused on managing the spinal deformity, AIS has broader implications for physical functioning, psychological well-being, and participation that often extend into adulthood. Consequently, a more holistic and long-term approach is required that integrates medical, personal, and societal perspectives to provide the best possible care. The overarching aim of this thesis was to improve patient outcomes by advancing a broader, more integrated understanding of AIS aligned with principles of value-based care. This thesis specifically sought to enhance understanding of the personal, medical, and societal challenges faced by individuals with AIS and to identify opportunities to optimize care delivery to address these challenges more effectively. To achieve this aim, AIS was investigated from multiple perspectives and organized into three complementary parts. Part I focused on mapping and optimization of the healthcare pathway. In Part II, innovative care approaches and strategies were explored, including technological innovations in brace treatment and the assessment of dynamic functioning through gait analysis. Finally, Part III evaluated the societal impact of AIS and the methodological considerations relevant to health economic evaluations. Part I: Mapping and optimizing the AIS healthcare pathway The first part of this thesis, presented in Chapter 2, addressed the mapping and optimization of the healthcare pathway for individuals with AIS. To gain insight into the functioning of the AIS healthcare pathway, a comprehensive evaluation was conducted at Maastricht University Medical Centre+, adopting a patient-centred approach and incorporating the perspectives of multiple stakeholders, including patients, parents, healthcare professionals, and external stakeholders. Integrating structural pathway mapping with qualitative evaluation facilitated the identification of both strengths and bottlenecks within the existing pathway, as well as avenues for improvement. Overall, the findings demonstrated that the pathway is characterized by professional commitment and generally positive interactions between patients and healthcare providers. However, opportunities for improvement were identified, including communication gaps, inconsistent information provision and differing expectations among stakeholders. Patients and parents reported uncertainty regarding treatment trajectories, decision-making processes, and long-term perspectives, as well as treatment-related burdens, including discomfort leading to challenges with brace-wear compliance. These findings indicate the need for more precise, consistent communication throughout the care journey. Furthermore, the emotionally demanding nature of AIS treatment highlighted the importance of psychosocial support and opportunities for peer contact. From the perspective of healthcare professionals, the findings emphasized the need for standardized information materials and improved interdisciplinary coordination to ensure consistent messaging and shared understanding across disciplines. By integrating pathway mapping with qualitative stakeholder perspectives, Part I of this thesis contributes to a structured approach for evaluating complex healthcare pathways and can serve as a blueprint for continuous quality improvement in AIS care as well as in other chronic or long-term conditions. Part II: Exploring innovative care approaches and strategies The second part of this thesis, presented in Chapters 3-5, explored innovative care approaches and strategies to address challenges in the non-operative management of AIS and to improve functional assessment. In Part I, treatment-related burdens such as brace discomfort were identified. To provide an overview of current three-dimensional developments, a scoping review was presented in Chapter 3. The scoping review examined the methodology and application of three-dimensional technology, including computer-aided design and manufacturing as well as 3D-printing, in the design and production of spinal orthoses for AIS. The review showed that these technologies present opportunities to enhance brace customization, fit, and reproducibility. However, considerable heterogeneity was observed in study designs, outcome measures, and reporting, and evidence regarding clinical effectiveness and long-term outcomes remains limited. These findings underscore a gap between technical innovation and clinical implementation. To address this translational gap, Chapter 4.1 presents a protocol outlining the steps to progress from mechanical prototype development to clinical implementation of a 3D-printed orthosis. The mechanical study depicted in Chapter 4.2 builds on this by providing insights into the technical performance of the brace. Both studies emphasize the need for iterative collaboration among clinicians, engineers, and industry partners, and incorporate considerations related to safety, feasibility, regulatory requirements, and clinical evaluation. By articulating these steps, this work offers guidance for the responsible translation of technological innovation into routine AIS care. While innovations in brace design represent an essential avenue for improving non-operative treatment, the findings in Part I also highlight the relevance of assessing physical functioning. Gait analysis provides a radiation-free method for evaluating dynamic function and offers complementary insight into how AIS affects mobility, balance, stability, and physical functioning in daily life. Accordingly, Chapter 5 examined gait characteristics in individuals with AIS using three-dimensional gait analysis. The findings indicated increased gait variability and altered gait patterns compared to matched healthy controls, offering functional insights not available through static radiographic assessment. Further research is necessary to assess the feasibility, clinical utility, and costs of incorporating gait analysis into routine clinical practice. Collectively, the studies in Part II demonstrate that innovative care strategies and approaches should be evaluated in a standardized manner including feasibility, clinical utility, workflow integration and costs prior to clinical implementation in order reach their full potential to improve patient outcomes and support value-based care delivery. Part III: Evaluating societal impact The third part of this thesis examines the broader societal impact of AIS by expanding the focus beyond individual patient care to encompass health-related quality of life (HRQoL) and economic consequences. Given the chronic nature of AIS and its potential effect on functioning and participation across a patient’s lifespan, adopting a societal perspective is necessary to assess the condition’s burden comprehensively. Chapter 6 presents a burden-of-disease study quantifying the impact of AIS on HRQoL, healthcare costs, and productivity losses. The results indicate that AIS leads to a substantial reduction in HRQoL compared to population norms. Furthermore, the economic burden is considerable, with productivity losses accounting for the largest share of total costs. These losses are attributable to reduced participation in paid employment due to absenteeism and diminished work performance. Together, these findings demonstrate that AIS is a medical condition with significant societal consequences extending beyond direct healthcare utilization. The results highlight the necessity of early intervention, increased awareness, and ongoing support throughout adolescence and adulthood, as well as preventive strategies to mitigate long-term effects on participation and productivity. Beyond quantifying societal burden, Chapter 7 addresses methodological considerations pertinent to health economic evaluation. This chapter empirically demonstrates how variations in reference prices influence cost estimates and affect the interpretation and comparability of economic evaluations across time and settings. The findings underscore the importance of transparent, standardized, and comparable costing methodologies in health technology assessment. Enhancing the consistency of cost calculations supports more reliable interpretation and comparison of health economic evidence, thereby reinforcing the foundation for resource allocation decisions, reimbursement policies, and national or international comparisons. By integrating health economic evaluation with clinical research, Part III connects individual well-being and societal costs to the broader context of public health. The studies in this section emphasize that comprehensive evaluation of AIS care must consider both patient outcomes and societal consequences, and that methodological transparency is critical for informing policy-relevant decision-making. Conclusion This thesis presents a comprehensive overview of AIS by analysing the healthcare pathway, innovations in care, and the broader societal impact of the condition. From a value-based perspective, this thesis demonstrates that AIS cannot be fully understood or addressed solely through a biomedical approach but instead requires consideration of patient experiences, functional outcomes, and long-term societal effects. Across the three parts of this thesis, several interrelated themes emerge. The organization of care pathways, including effective communication, continuity, and stakeholder alignment, plays a central role in shaping patient and caregiver experiences. Innovations such as technological advancements in brace treatment and functional assessment by gait analysis, offer potential for improving care but require rigorous evaluation of clinical relevance, feasibility, and integration into existing pathways. Furthermore, AIS imposes a significant lifelong burden on individuals and society, particularly by affecting health-related quality of life and participation, underscoring the importance of adopting a broader societal perspective when evaluating care. Together, the findings of this thesis emphasize the need for an integrative, long-term approach to AIS care that aligns clinical outcomes with patient-centred goals and societal considerations, consistent with principles of value-based care. By integrating pathway organization, innovation, and societal evaluation, this thesis provides a more comprehensive understanding of AIS and establishes a foundation for future initiatives aimed at enhancing the quality and patient-centredness of care for individuals with AIS.