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Nonlinear millimeter scales colored like streetlights to indicate extractability for basket sizes indicated
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Introduction:
Endoscopic treatment of ureter stones and renal calculi relies on the surgeon's estimation of the stone size for both lithotripsy and removal of stones or stone fragments. We therefore compared precision and reliability of the endoscopic estimation of stone size by the surgeon with measurements on a scale on a stone basket.
Material...
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Background:
The ureterointestinal anastomosis stricture (UAS) is a common complication of urinary diversion after radical cystectomy. For decades, open anastomotic revision remained the gold standard for the treatment of UAS. However, with the advancement in endoscopic technology, mini-invasive therapeutic approaches have been used in its manageme...
Introduction:
Endourological intervention is a minimally invasive approach for the management of ureteral strictures. Contraindications to this approach include active infection, strictures of sizes >2 cm, and failure of endoureterotomy. This report demonstrates a case of successful dual stent placement after redo endoureterotomy.
Case presentati...
Citations
... Secondly, intraoperative real-time measurements were performed with assistance of stone basket as a reference. In the study by Cordes et al [8] [9] , a standard nonlinear scale in millimeters was established on the handle of the basket to measure the intraoperative stone size. In addition, Cordes et al [10] further improved the material of the basket and on the handle implemented an improved scale for accurate intraoperative stone size measurement. ...
Purpose
To investigate the application value of intraoperative real-time measurement in retrograde intra-renal surgery (RIRS), and to analyze the clinical characteristics of perioperative stones and the factors affecting the efficient removal of stone fragments.
Methods
In RIRS a total of 67 extraction procedures of stones were retrospectively analyzed. Flexible ureteroscopy with 8.4F URF P-5 (Olympus, Tokyo, Japan) and UAS with F12/14 navigator HD (Boston Scientific, Natick, Ma, USA) were employed intraoperatively. Judge the region of stone fragments in the field of vision, which is divided into the region within 1/3 of the diameter, 1/3 to 1/2, 1/2 to 2/3 and more than 2/3. Record whether the stone fragments can be removed through UAS. The size of stone fragments was determined by the electronic caliper. Analyze the surgical video images, and measure the relative endoscopic horizontal size (REHS) and the relative endoscopic maximum size (REMS) of stones and record whether the stone fragments can be removed through UAS.
Results
All operations were successful, and 67 extraction procedures of stones were performed, with 48 cases in the passable group and 19 cases in the non-passing group. The success rate of stone fragments removal in each region was 93.3% in 1/3 region, 86.8% in 1/3 to 1/2 region, 8.3% in 1/2 to 2/3 region and 0% in more than 2/3 region. That is, 88.7% of the stones located in 1/2 region were successfully removed. Comparing the receiver operating characteristic curve (ROC curve) of REHS and REMS, the area under the curve (AUC) of REHS was 0.895 (95% CI: 0.796–0.956), and the AUC of REMS was 0.797 (95% CI: 0.681–0.885); The difference of AUC between the two methods was 0.0981, the Z-statistic was 1.137, P = 0.02555, and the predictive value of REHS was higher than that of REMS. And then the ROC curve of REHS was analyzed. The maximum cutoff value was 0.47, AUC is 0.895 (sensitivity 78.9% and specificity 89.6%). According to the clinical application value of real-time intraoperative measurement, 0.50 was selected as the actual cutoff value, with the AUC 0.811, P < 0.0001 (sensitivity 68.4% and specificity 93.7%). According to the REHSS cutoff value of 0.5 (namely "one-half principle"), the factors that prevent stones from being removed include irregular stone shape, irregular grasping of stones by the stone basket, poor position of the ureteral channel sheath, and hard stone texture and so on.
Conclusion
When the stone basket is utilized for real-time measurement during flexible ureteroscopy, it is possible to determine efficiently and reliably that stone fragments are removed through UAS with the REHS maximum cutoff value of 0.5, namely "one-half principle". This approach of prediction is anticipated to increase operation effectiveness, shorten operation duration, and increase stone removal rate.
... A specialized basket, designed to measure stone size, has also been studied in benchtop modeling [13,14]. In this study, newly developed basket handles were gaged with size markings to measure the size of the stone held in the basket, with measurements to the nearest millimeter. ...
... In this study, newly developed basket handles were gaged with size markings to measure the size of the stone held in the basket, with measurements to the nearest millimeter. With the initial prototype, the accuracy of size estimation was inferior to visual size estimates made endoscopically by urologists [13], and a second prototype was developed, which is yet to be tested [14]. Developing a basket or other such instrument that could measure stones and fragments endoscopically could ultimately result in highly accurate measurements; however, the greatest limitation of this method is surgical efficiency. ...
PurposeBasketing plays an important role during flexible ureteroscopy, but it can be time-consuming, especially when fragments are too large to pass through the ureteral access sheath. We aim to present the optimal on-screen, endoscopic stone size that predicts successful basketing through various access sheaths.MethodsA tipless basket, individually extended to 5 mm from multiple ureteroscopes: (Flex-Xc, Karl Storz; Flex-X2s, Karl Storz; LithoVue, Boston Scientific; or URF-P6R, Olympus) and via differently sized access sheaths (10–12 Fr through 13–15 Fr), was used in retrieval attempts of various artificial stone sizes (2 mm through 5 mm). A relative endoscopic stone size was recorded as the stone’s maximum diameter on endoscopic view compared to the total image diameter.ResultsBasketing of stones up to 2.5 mm, yielding relative endoscopic stone sizes of 0.38 (Flex-Xc), 0.30 (Flex-X2s), 0.32 (LithoVue), and 0.34 (URF-P6R), was successful using all access sheaths. Only the 12–14 Fr and greater sheaths allowed for successful basketing of 3 mm stones. Larger stones did not successfully pass through any of the access sheaths.Conclusion
Successful stone retrieval can be predicted by estimating the stone’s size on screen, which is influenced by the type of flexible ureteroscope and access sheath. In our testing, stones of approximately one-third of the screen size passed successfully in all cases.
... This principle proved to achieve a high accuracy for endoscopic stone particles size estimation in a recent study, although fragments < 1 mm were not analyzed in that study [33]. Another study using stone baskets for calibration also revealed a high accuracy for size estimation of stones ranging 2-7 mm and additionally evidenced a bias depending on stone color, basket size, and experience of the surgeon [34]. ...
PurposeTo propose a size-related definition of stone dust produced by lithotripsy of urinary stones.Methods
Stone dust was defined as particles small enough to adhere to the following criteria: (1) spontaneous floating under 40 cm H2O irrigation pressure; (2) mean sedimentation time of > 2 s through 10 cm saline solution; (3) fully suitable for aspiration through a 3.6 F working channel. Irrigation, sedimentation, and aspiration tests were set up to evaluate each criterion. Primary outcome was particle size limit agreeing with all three criteria. Stone particles with a given size limit (≤ 2 mm, ≤ 1 mm, ≤ 500 µm, ≤ 250 µm, ≤ 125 µm and ≤ 63 µm) were obtained from laser lithotripsy, including samples from prevailing stone types: calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, carbapatite, struvite, brushite, and cystine.ResultsAll particles ≤ 250 µm from all stone types were in agreement with all three criteria defining stone dust, except for struvite where size limit for a positive irrigation and sedimentation test was ≤ 125 µm.ConclusionA size limit of ≤ 250 µm seems to generally adhere to our definition of stone dust, which is based on floating and sedimentation proprieties of stone particles, as well as on the ability to be fully aspirated through the working channel of a flexible ureteroscope.
Introduction:
Accurate estimation of stone fragment size during ureteroscopic lithotripsy procedures facilitates operative efficiency and predicts the safety of fragment extraction or spontaneous passage. Using a novel stone measurement software application, this study assesses the feasibility of performing integrated, real-time digital stone measurement during ureteroscopy.
Methods:
This workflow feasibility study was conducted in two phases. First, in the ex vivo simulation, mock stone fragments were placed in a renal collecting system training model. A basket extraction task was performed using a digital ureteroscope, with and without digital stone measurement. The time required to perform the tasks was recorded and compared. Second, in the in vivo workflow trial, adult patients undergoing ureteroscopic stone procedures were prospectively enrolled. Intraoperative measurements of stone fragments were performed to determine the time required to complete the measurements. Technical failures and perioperative complications were recorded.
Results:
In the ex vivo simulation, 20 mock stones mimicking varied fragmentation conditions were tested in the training model. The mean completion time of the basketing task without versus with digital stone measurement was 16.5 seconds (range 10.2-33.7) versus 38.9 seconds (range 27.2-60.0). Mean additional time required to measure stones was 22.3 seconds (range 8.4-42.7). In the in vivo workflow trial, 9 patients undergoing ureteroscopy were enrolled. A median of 5 fragments (range 3-10) were measured in each patient. Mean completion time for each measurement was 10.1 seconds (range 8.2-12.8). Mean total time required to perform digital measurement per procedure was 50.8 seconds (range 25.9-99.0). No technical failures or clinical complications were observed.
Conclusions:
Integrating real-time digital stone measurement during ureteroscopy is safe and feasible. The findings support clinical trials of digital stone measurement to enhance intraoperative decision-making during ureteroscopy.
Disposable stone retrieval devices are an inherent element of modern-day stone management. Efforts are being made in several different areas to improve the efficiency of stone removal. Ureteral access sheaths with pressure control features as well as suction capabilities are being explored as one such mechanism. Additional efforts are being made to improve stone basket design, grasping capabilities, and deployment mechanisms. Finally, bioadhesives are being developed to potentially improve the capability to extract otherwise difficult small stone fragments and debris from the kidney.
Introduction:
Intraoperative assessment of stone size is crucial for the successful and safe extraction of stones. The first automatically fixating measuring stone basket prototype showed a mismatch between the steel spring and the nitinol basket; therefore, to improve this prototype, the steel spring was replaced with a nitinol spring and a modified scale was implemented on the basket handle for accurate intraoperative stone size measurement.
Methods:
The proposed tipped basket was composed of nitinol. A standard handle with a spring-supported self-closing mechanism (2.5 F, Urotech®) was used, and a modified nonlinear millimeter scale was established on the handle. The grasping force was provided by the new nitinol spring mechanism in the handgrip. Various colors associated with the stone size were applied on the scale.
Results:
The material difference between the basket and the spring was eliminated. The measuring scale ranged from 2 mm (green) through 5 mm (yellow) to 8 mm (red), and the scale was nonlinear because of the nonlinear relationship between the diameter of the stone and the distance marked on the scale.
Conclusion:
The proposed automatically fixating stone basket with a nitinol spring has the potential to improve the safety and effectiveness of endourological stone retrieval. Further validation of this new scale and basket should follow.
