Supra-Alveolar Bone Regeneration: Progress, Challenges, and Future Perspectives.

Periodontitis is a highly prevalent disease that damages the supporting tissues of a tooth, including the alveolar bone. Alveolar bone loss owing to periodontitis is broadly categorized as supra-alveolar and intra-alveolar bone loss. In intra-alveolar bone loss, the defect has an angular or oblique orientation to the long axis of the tooth in an apical direction. In contrast, the defect is perpendicular to the long axis of the tooth in supra-alveolar bone loss. Unlike intra-alveolar bone defects, supra-alveolar bone defects lack supporting adjacent space, which makes supra-alveolar bone regeneration more challenging. In addition, the limited availability of resources in terms of vascularity and underlying tissues is another obstacle to supra-alveolar bone regeneration. Currently, supra-alveolar bone loss is the least predictable periodontal defect type in regenerative periodontal therapy. In addition, supra-alveolar bone loss is much more common than other alveolar bone loss. Despite its prevalence, research on supra-alveolar bone regeneration remains sparse, indicating an unmet need for significant research efforts in this area. This review summarize recent advances, obstacles, and future directions in the field of supra-alveolar bone regeneration. We discuss the biomaterials, bioactive molecules, and cells that have been tested for supra-alveolar bone regeneration, followed by pre-clinical and clinical approaches employed in this field. Additionally, we highlight obstacles and present future directions that will propel supra-alveolar bone research forward.

Adjuvant Chemotherapy in Patients with Locally Advanced Upper Tract Urothelial Carcinoma with or without Kidney Transplantation.

Background: The incidence of upper tract urothelial carcinoma (UTUC) is uniquely high in kidney transplant (KT) recipients in Taiwan. The evidence of adjuvant chemotherapy (AC) in UTUC is contradictory. We have sought to determine whether AC is associated with potential benefits related to locally advanced UTUC after KT. Methods: We retrospectively analyzed 134 patients with locally advanced UTUC (at least stage T2) and patients who were administrated AC after unilateral or bilateral nephroureterectomy with bladder cuff excision. Of these 134 patients, 57 patients fulfilled our inclusion criteria. We used 23 KT and 34 non-KT locally advanced UTUC patients for comparison. Results: The mean follow-up time was 52.35 ± 34.56 and 64.71 ± 42.29 months for the KT and non-KT groups, respectively. The five-year disease-free survival (DFS) and overall survival (OS) rates were 45.7% vs. 70.2% and 62.8% vs. 77.6%, for the KT and non-KT groups. The Kaplan-Meier curve and the log rank test revealed significant differences in the DFS and OS rates between the two groups, p = 0.015 and 0.036. The influence of chemotherapy on graft kidney function was mild. Only three in the KT group and two in the non-KT group developed > grade 2 nephrotoxicity. Conclusions: Our study suggested that KT patients with locally advanced UTUC who had been administered AC after surgery presented worse OS and DFS than non-KT patients. KT patients tolerated the AC course well, and their nephrotoxicity levels were mild and acceptable.

Feasibility estimation of injected hydrodissection before definitive radiotherapy of pancreatic adenocarcinoma.

BACKGROUND: Pancreatic adenocarcinoma is often not diagnosed until an advanced stage, and so most patients are not eligible for resection. For patients who are inoperable, definitive radiotherapy is crucial for local disease control. However, the pancreas is located close to other vulnerable gastrointestinal organs, making it challenging to deliver an adequate radiation dose. The surgical insertion of spacers or injection of fluids such as hydrogel before radiotherapy has been proposed, however, no study has discussed which patients are suitable for the procedure. METHODS: In this study, we reviewed 50 consecutive patients who received definitive radiotherapy at our institute to determine how many could have benefitted from hydrodissection to separate the pancreatic tumor from the adjacent gastrointestinal tract. By hypothetically injecting a substance using either computed tomography (CT)-guided or endoscopic methods, we aimed to increase the distance between the pancreatic tumor and surrounding hollow organs, as this would reduce the radiation dose delivered to the organs at risk. RESULTS: An interventional radiologist considered that hydrodissection was feasible in 23 (46%) patients with a CT-guided injection, while a gastroenterologist considered that hydrodissection was feasible in 31 (62%) patients with an endoscopic injection. Overall, we found 14 (28%) discrepancies among the 50 patients reviewed. Except for 1 patient who had no available trajectory with a CT-guided approach but in whom hydrodissection was considered feasible with an endoscopic injection, the other 13 patients had different interpretations of whether direct invasion was present in the CT images. CONCLUSION: Our results suggested that about half of the patients could have benefited from hydrodissection before radiotherapy. This finding could allow for a higher radiation dose and potentially better disease control.

Effect of iodized oil embolization on temperature change during cryoablation for renal cell carcinoma.

INTRODUCTION: We aimed to evaluate the effect of transcatheter arterial embolization (TAE) with iodized oil (Lipiodol) on temperature change during cryoablation (CA) for renal cell carcinoma (RCC). MATERIAL AND METHODS: We retrospectively reviewed patients receiving CA for RCC from February 2020 to July 2021, including those who received Lipiodol TAE prior to CA (TAE group) and those who underwent only CA with comparable clinical and tumor characteristics (non-TAE group). Clinical data and tumor characteristics of both groups were recorded. The temperature readings of each cryoprobe at every 15 s and 'time to -100 °C' were compared between the groups. RESULTS: A total of 17 patients with 18 RCCs were recruited (seven in the TAE group and 11 in the non-TAE group). The 'time to -100 °C' was significantly longer in the TAE group than in the non-TAE group (64.5 ± 24.3 s vs. 48.8 ± 9.7 s, p = 0.018). Positive correlation between 'time to -100 °C' and tumor maximal diameter, RENAL nephrometry and PADUA score were observed in the non-TAE group, while no corresponding correlation was found in the TAE group. CONCLUSIONS: Pre-embolization with iodized oil influences the temporal temperature changes during cryoablation by disrupting the positive correlation between the time to reach the target temperature and tumor characteristics.