ABSTRACT
Thermoset materials sacrifice recyclability and reshapeability for increased chemical and mechanical robustness because of an immobilized, cross-linked polymeric matrix. The robust material properties of thermosets make them well-suited for applications such as heat-shielding materials (HSMs) or ablatives where excellent thermal stability, good mechanical strength, and high charring ability are paramount. Many of these material properties are characteristic of covalent adaptable networks (CANs), where the static connectivity of thermosets has been replaced with dynamic cross-links. This dynamic connectivity allows network mobility while retaining cross-link connectivity to permit damage repair and reshaping that are traditionally inaccessible for thermoset materials. Herein, we report the synthesis of hybrid inorganic-organic enaminone vitrimers that contain an exceptionally high weight percent of polyhedral oligomeric silsesquioxane (POSS)-derivatives. Polycondensation of ß-ketoester-containing POSS with various diamine cross-linkers led to materials with facile tunability, shapeability, predictable glass transition temperatures, good thermal stability, and high residual char mass following thermal degradation. Furthermore, the char materials show notable retention of their preordained shape following decomposition, suggesting their future utility in the design of HSMs with complex detailing.
ABSTRACT
INTRODUCTION: The incidence of kidney cancer has increased significantly over the past few decades presumably due to the increased use of imaging. The aim of this article is to describe contemporary outcomes of ablative therapy and to compare them to other therapeutic options in terms of oncological, functional, perioperative outcomes and cost. MATERIAL AND METHODS: We searched MEDLINE®, Embase®, using (MeSH) words; from January 2005 through May 2017, and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance. RESULTS: Ninety-one articles were analyzed. We described the outcomes of ablative therapy in relation to the energy used and the approach, and compared these outcomes to the other therapeutic options in terms of oncological, functional and perioperative outcomes. We analyzed these studies in order to search for predictive factors influencing the results of ablative therapy. We also analyzed the economic burden of small renal tumor management. CONCLUSION: The strength of evidence is based almost entirely on retrospective studies and is susceptible to the inherent limitations of this study design. Although, the evidence was low among studies, our revue showed that, in elderly patients treated with ablative therapy for cT1a tumors, the cancer-specific survival was comparable to partial nephrectomy with differences in overall survival that are explained by competing risks of death in the old population. Considering the functional results, the renal function preservation seems to be comparable between the 2 groups while the perioperative morbidity is higher in the partial nephrectomy group. The evidence base medicine at this time cannot support the extension of the indications of ablative therapy beyond the actual implementations.
Subject(s)
Ablation Techniques , Kidney Neoplasms/surgery , Humans , Kidney Neoplasms/mortality , Length of Stay , Nephrectomy , Postoperative Complications , Quality of LifeABSTRACT
OBJECTIVES: Ablative treatment (AT) rise is foreseen, validation of steps to insure good proceedings is needed. By looking over the process of the patient, this study evaluates the requirements and choices needed in every step of the management. METHODS: We searched MEDLINE®, Embase®, using (MeSH) words and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance. RESULTS: Explanations of AT proposal rather than partial nephrectomy or surveillance have to be discussed in a consultation shared by urologist and interventional radiologist. Per-procedure choices depend on predictable ballistic difficulties. High volume, proximity of the hilum or of a risky organ are in favor of general anesthesia, cryotherapy and computed tomography/magnetic resonance imaging (CT/MRI). Percutaneous approach should be privileged, as it seems as effective as the laparoscopic approach. Early and delayed complications have to be treated both by urologist and radiologist. Surveillance by CT/MRI insure of the lack of contrast-enhanced in the treated area. Patients and tumors criteria, in case of incomplete treatment or recurrence, are the key of the appropriate treatment: surgery, second session of AT, surveillance. CONCLUSION: AT treatments require patient's comprehension, excellent coordination of the partnership between urologist and radiologist and relevant choices during intervention.
Subject(s)
Kidney Neoplasms/surgery , Ablation Techniques , Anesthesia, General , Anesthesia, Local , Conscious Sedation , Humans , Kidney Neoplasms/diagnostic imaging , Postoperative Care , Preoperative Care , Surgery, Computer-AssistedABSTRACT
BACKGROUND: Ablative therapies (AT) in kidney cancer are rising. It's important to evaluate the situation of this therapy. The aim of this study is to identify the best indications for AT treatment for kidney cancer. METHODS: Review of literature using Medline and Embase databases. Study were selected based on scientific relevance. Clinical keys centered on the best requirements to indicate ablative therapies. RESULTS: AT is indicated according to specific tumor and patients criteria. A good initial evaluation is essential (imaging, pathology, renal function and general condition of the patient). AT gets the best results when applied to the following tumor criteria: solid tumor, length<3cm, exophytic localization, RENAL score<8. In few cases, AT could be discussed as an alternative to the reference treatment, sparing surgery: life expectancy evaluated between 3 and 7 years, chronic renal failure or single kidney, transplanted kidney, familial tumors. AT can be used in first line, post-surgery after local recurrence or for distant metastasis. Like every other innovative technic, indications of AT would be adjust with learning curve and cost-effectiveness. CONCLUSION: AT have to be included as a valid treatment for kidney cancer<4cm. The respect of actual indications and collection of results of AT compared to surveillance and surgery, would determinate the evolution of AT indications in the future.
Subject(s)
Ablation Techniques , Kidney Neoplasms/surgery , Biopsy , Decision Trees , Humans , Kidney Neoplasms/diagnostic imaging , Kidney Neoplasms/pathology , Neoplasm Metastasis , Patient SelectionABSTRACT
Os lasers ablativos, como o laser de CO2 (10.600 nm) e o erbium:YAG (Er:YAG-2.940 nm), removem a epiderme e provocam dano térmico residual na derme. Apresentam algumas desvantagens, como tempo de recuperação prolongado, não podem ser usados fora do rosto e têm risco significativo de efeitos colaterais. Para reduzir esses efeitos colaterais, surgiram os lasers não ablativos, que penetram profundamente na pele e aquecem a derme, poupando a epiderme. Seus efeitos colaterais e o tempo de recuperação são mínimos porém, comparado ao resurfacing ablativo, têm eficácia modesta e requerem múltiplos tratamentos. Lasers fracionados não ablativos foram desenvolvidos para rejuvenescimento cutâneo semelhante ao do laser de CO2, sem os inconvenientes e o pós-operatório deste. O princípio do laser fracionado é poupar áreas de pele sãs entre as áreas tratadas, facilitando e promovendo uma cicatrização mais rápida a partir das áreas poupadas. O resurfacing fracionado não ablativo apresenta bons resultados para o tratamento de rugas finas a moderadas e outros sinais do fotoenvelhecimento cutâneo. Outras indicações são cicatrizes atróficas, cicatrizes de acne, cicatrizes cirúrgicas e há relatos da eficácia no melasma. O tempo de recuperação é rápido, mas os resultados são inferiores aos obtidos com os tratamentos ablativos. Recentemenente surgiram os lasers fracionados ablativos de CO2 (10.600 nm) e érbio (Er:YAG 2.940 nm), com o intuito de se alcançar um resultado semelhante ao dos lasers ablativos, porém com recuperação e risco de efeitos colaterais mais próximos ao dos lasers fracionados não ablativos, já que também poupam áreas de pele sãs entre as áreas tratadas.