京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13029号 / 論医博第2111号 / 新制||医||1016(附属図書館) / 32987 / (主査)教授 大森 孝一, 教授 別所 和久, 教授 坂井 義治 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

The use of injectable biomaterials is growing as the demands for minimally invasive procedures, and more easily applicable implants become higher, but their availability is still limited due to the difficulties associated to their design. Each year, more than 700,000 vertebral compression fractures (VCF’s) are reported in the US and 500,000 VCF’s in Europe due to primary osteoporosis only. VCF’s can compromise the delicacy of the spinal canal and also cause back pain, which affects the patient’s quality of life. Vertebroplasty was developed in the 80’s, and has proven to be a safe minimally invasive procedure that can, quickly and sustainably, relieve the pain in patients experiencing VCF’s. However, biomaterials for vertebroplasty still have limitations. For instance, ceramic bone cements are difficult to distinguish from the bone using X-ray techniques. On the other hand, acrylic bone cements may cause adjacent vertebral fractures (AVF’s). Large clinical studies have indicated that 12 to 20% vertebroplasty recipients developed subsequent vertebral fractures, and that 41 to 67% of these, were AVF’s. This may be attributed to the load shifting and increased pressure on the adjacent endplates reached after vertebroplasty with stiff cements. The primary aim of this thesis was to develop better injectable biomaterials for spinal applications, particularly, bone cements for vertebroplasty. Water-soluble radiopacifiers were first investigated to enhance the radiopacity of resorbable ceramic cements. Additionally, different strategies to produce materials that mechanically comply with the surrounding tissues (low-modulus bone cements) were investigated. When a suitable low-modulus cement was produced, its performance was evaluated in both bovine bone, and human vertebra ex vivo models. In summary, strontium halides showed potential as water-soluble radiocontrast agents and could be used in resorbable calcium phosphates and other types of resorbable biomaterials. Conversely, linoleic acid-modified (low-modulus) cements appeared to be a promising alternative to currently available high-modulus cements. It was also shown that the influence of the cement properties on the strength and stiffness of a single vertebra depend upon the initial bone volume fraction, and that at low bone volume fractions, the initial mechanical properties of the vertebroplasty cement become more relevant. Finally, it was shown that vertebroplasty with low-modulus cements is biomechanically safe, and could become a recommended minimally invasive therapy in selected cases, especially for patients suffering from vertebral compression fractures due to osteoporosis.

This review aimed to evaluate orthotic treatments for children and adolescents with pectus carinatum, primarily focusing on patient satisfaction with the treatment. Secondary outcomes of interest were adherence and psychological and social factors following the treatment period. A literature search was performed in the databases CINHAL, Medline, Web of Science and Scopus. Following predetermined eligibility criteria, articles were included and excluded. Next, criticala ppraisal was performed for the included articles. Following this, relevant data were extracted, analysed, and presented to aid in answering the research questions. Six articles with 402 patients were included in the final review. Patient satisfaction was good or improved following the treatment period, and the combined non-adherence rate for the included orthosis was 37.7 %. Patients adhering to the treatment protocol showed increased self-esteem and decreased interference with social activity following orthotic correction. Moreover, they displayed significantly higher patient satisfaction than patient's non-adherent to the treatment protocol. The findings were displayed and discussed in the Bio-Psycho-Social model. Due to their connection, patient satisfaction and adherence were placed together in the middle and surrounded bypsychological and social factors. The model displayed that a combination of many aspects determines patient satisfaction and adherence, demonstrating that treatment is complex and challenging. In conclusion, adherence was deemed one of the most important aspects to achieve high patient satisfaction. Moreover, due to psychological and social factors, a patient-centred approach with professional collaboration is necessary to achieve successful outcomes. To make reliable conclusions, research of higher quality with long follow-up periods including standardised patient satisfaction and adherence measures is needed.