Flexible ureteroscopy in Chinese air force pilots with renal calculi: a cohort study at a single medical centre.

INTRODUCTION: Renal calculi are the predominant urological ailment in air force pilots. Flexible ureteroscopy (FURS) constitutes a valuable approach for renal calculi treatment. This study presents a decade-long exploration of using FURS for renal calculi treatment in air force pilots. Additionally, it investigates the safety and feasibility of granting waiver flights to pilots with renal parenchyma calcification. METHODS: From December 2009 to December 2019, a retrospective review was conducted on Chinese air force pilots undergoing treatment for renal calculi. Among the pilots assessed, a total of 71 individuals underwent FURS. Endoscopic methodology involved the insertion of a flexible ureteroscope into the ureter and renal pelvis, guided by a safety wire. Stone fragmentation was achieved using a holmium laser fibre, followed by extraction using a soft stone basket. Postoperative non-enhanced CT (NECT) scans was used to confirm stone clearance. Furthermore, clinical diagnoses were classified based on endoscopic findings and postoperative NECT results. All data were presented as mean (SD) or median (minimum-maximum) for continuous variables and frequency counts and percentages for categorical variables. RESULTS: FURS identified free kidney stones in 60 cases among all patients. The remaining 11 cases, without free stones detected during ureteroscopy, exhibited persistent high-density spots on postoperative NECT. Of the 60 cases with stones, renal calculi were successfully cleared in 30 pilots, while the remaining 30 exhibited persistent high-density spots on NECT postsurgery. Pilots with completely cleared free stones were deemed fit for flight. Pilots with diagnosed renal parenchyma calcification were granted permission to fly under waivers following a meticulous evaluation. CONCLUSIONS: FURS could not only effectively eliminate renal calculi but also accurately diagnose renal parenchyma calcification, facilitating a prompt return to flight for pilots. A protocol for managing pilot renal calculi, informed by FURS and our experience, is proposed.

A new method for accurate inversion of Forel-Ule index using MODIS images - revealing the water color evolution in China's large lakes and reservoirs over the past two decades.

The Forel Ule water color index (FUI) based on satellite inversion can characterize the comprehensive characteristics of water quality on a large spatiotemporal scale. The high-frequency observations and rich historical data of the MODIS surface reflectance product (MODIS-500 m) provide important data support for monitoring the FUI of inland lakes. However, MODIS-500 m has only three bands in the visible light range, resulting in significant uncertainty in FUI inversion. To address this problem, this study developed an improved FUI inversion model using 500 synthetic spectra covering natural waters. The model, with a performance threshold set at 170° (FUI = 8), used a segmented algorithm across the entire color space. Validated with on-site measurement datasets (3500 samples), the model exhibited excellent performance, with mean relative error (MRE) and root mean square error (RMSE) of 1.71 % and 3.63°, respectively. Compared to existing models, it was more suitable for long-term FUI inversion in various types of lakes, particularly in eutrophic regions. Subsequently, the model was applied to MODIS-500 m observations from 2000 to 2022, revealing the spatiotemporal dynamics of FUI in 180 large lakes and reservoirs (hereinafter referred to as lakes) in China. The results indicated that the long-term mean FUI in the study area was 9, with 7 and 12 in the western and eastern regions, respectively, showing a distinct spatial distribution of "blue in the west and green in the east." The mean change rate of hue angle for all lakes was -0.085°/yr, showing an overall decreasing trend. Environmental factors' relative contributions to long-term water color changes in each lake region were quantified using the multiple general linear model (GLM). Although each lake region exhibited different driving forces, they were primarily influenced by vegetation, lake surface area, and anthropogenic factors. Additionally, the seasonal types of lake water color were analyzed, with the west and east showing opposite patterns, reflecting the significant influence of topographic features and seasonal changes in climate on water color. The research results provide techniques for accurate inversion of FUI using MODIS-500 m data, while deepening the understanding of long-term water color changes in inland lakes in China.

Several key issues must be noted in determining postoperative analgesic efficacy of intercostal nerve block for thoracoscopic surgery.

The letter to the editor was written in response to "The effect of ultrasound-guided intercostal nerve block on postoperative analgesia in thoracoscopic surgery: a randomized, double-blinded, clinical trial", which was recently published by Li et al. (J Cardiothorac Surg 18(1):128, 2023). In this article, Li et al. showed that addition of a preoperative intercostal nerve block to the multimodal analgesic strategy significantly reduced the pain scores within 48 h after surgery. However, we noted several issues in this study that were not well addressed. They were no use of a standard opioid-sparing multimodal analgesic strategy recommended in the current Enhanced Recovery After Surgery protocols for thoracic surgery, the lack of clear description for reasonable selection of rescue analgesics, the interpretion of between-group differences in the postoperative pain scores based on only statistical differences rather than clinically meaningful differences, inclusion of patients who were not blinded to study intervention, not reporting cumulative opioid consumption and complications of intercostal nerve block. We believe that clarification of these issues is not only useful for improving design quality of randomized clinical trials which assess postoperative analgesic efficacy of nerve blocks, but also is helpful for the readers who want to use an opioid-sparing multimodal protocol including a nerve block in patients undergoing thoracoscopic surgery.