Three-dimensional mean stone density on non-contrast computed tomography can predict ureteroscopic lithotripsy outcome in ureteral stone cases

Role of Noncontrast Computed Tomography Parameters in Predicting the Outcome of Extracorporeal Shock Wave Lithotripsy for Upper Urinary Stones Cases: A Meta-analysis

RATIONALE

Extracorporeal shock wave lithotripsy (ESWL) is widely considered the primary approach for managing urinary tract stones. This study aimed to assess the predictive factors associated with non-contrast computed tomography (NCCT)-based parameters of upper urinary stones in relation to the outcomes of ESWL.

MATERIALS AND METHODS

A systematic search was conducted in PubMed, ScienceDirect, Web of Science, and Cochrane Library to identify all relevant studies published up to June 3, 2023. Several NCCT-based parameters to predict ESWL outcomes, comprised of mean stone density (MSD), skin-to-stone distance (SSD), and stone size, were extracted and analyzed using Review Manager software.

RESULTS

Out of 979 publications screened, a total of 39 publications, involving 7869 patients, were enrolled in the analysis. The pooled estimate demonstrated significant differences between MSD, and stone size between successful and failure of stone fragmentation groups, in which lower values of these parameters are associated with successful ESWL outcomes.

CONCLUSION

The results from the current study suggested that lower NCCT parameters, notably MSD, SSD, and stone size, are significantly associated with successful ESWL outcome. However, additional large-scale prospective studies are required to utilize these parameters effectively, and the optimal cutoff value should be determined.

Ureteroscopy and lasertripsy with pop dusting using high power holmium laser for large urinary stones > 15 mm: 6.5-year prospective outcomes from a high-volume stone center

INTRODUCTION

Ureteroscopy and stone lasertripsy (URSL) is a recognized technique for treatment of urinary tract stones. Holmium:Yag laser has been successfully used for this purpose for the last two decades. More lately, pulse modulation with Moses technology and high power lasers have been introduced with the result of faster and more efficient stone lasertripsy. Pop dusting is a two-stage combined treatment using a long pulse Ho:YAG laser, initially in contact mode with the stone 'dusting' (0.2-0.5 J/40-50 Hz) followed by non-contact mode 'pop-dusting' (0.5-0.7 J/20-50 Hz). We wanted to look at the outcomes of lasertripsy for renal and ureteric stones using a high-power laser machine.

METHODS

Over a period of 6.5 years (January 2016-May 2022), we prospectively collected data for patients undergoing URSL for stones larger than 15 mm treated using high power Ho:YAG laser (60W Moses or 100W laser). Patient parameters, stone demographics and outcomes of URSL were analyzed.

RESULTS

A total of 201 patients, underwent URSL for large urinary stones. In 136 patients (61.6%) stones were multiple and the mean single and cumulative stone size was 18 mm and 22.4 mm respectively. A pre- and post-operative stent was placed in 92 (41.4%) and 169 (76%) respectively. The initial and final stone free rate (SFR) were 84.5% and 94% respectively and 10% patients underwent additional procedure to achieve stone free status. 7 (3.9%) complications were recorded, all related to UTI/sepsis, with 6 Clavien II and 1 Clavien IVa complication.

CONCLUSION

Dusting and pop-dusting has shown to be successful and safe with the ability to treat large, bilateral or multiple stones with low retreatment and complication rates.

The association between ureteral wall thickness and need for additional procedures after primary ureteroscopy in patients with ureteral stones above the iliac crest

PURPOSE

To examine the parameters affecting the need for additional procedures in the primary ureteroscopy treatment in patients with ureteral stones above the iliac crest level.

METHODS

Seventy-one patients were included in the study who were ≥ 18 years old and had undergone ureteroscopy (URS) for ureteral stones above the iliac crest level between 2018-2020 and had a non-contrast-enhanced abdominal computed tomography before the procedures were included in the study. Patients and stone characteristics were prospectively collected. The results were evaluated six weeks after URS. The absence of any residual fragment was thought to indicate stone-free status. The patients with failure were referred for the additional procedures.

RESULTS

The median patient age was 51 years [interquartile range (IQR): 18-66]. The median transverse stone diameter was 9.5 mm (IQR: 7.1-11.4), and the median ureteral wall thickness (UWT) was 5.8 mm (IQR: 4.3-6.5). In the univariate analysis, UWT (p < 0.001), presence of multiple stones (p = 0.008), and stone length (p = 0.022) affected stone-free status. The multivariate analysis revealed UWT as the only independent factor affecting the need for additional procedures after URS (p = 0.028). In the receiver operating characteristic curve analysis, the best threshold value for UWT according to the outcomes was identified as 5.8 mm.

CONCLUSION

Ureteral wall thickness was the only independent parameter determining the need for additional procedures and affecting the treatment outcomes after the URS procedure.

Imaging in stone diagnosis and surgical planning

PURPOSE OF REVIEW

Radiological imaging techniques and applications are constantly advancing. This review will examine modern imaging techniques in the diagnosis of urolithiasis and applications for surgical planning.

RECENT FINDINGS

The diagnosis of urolithiasis may be done via plain film X-ray, ultrasound (US), or contrast tomography (CT) scan. US should be applied in the workup of flank pain in emergency rooms and may reduce unnecessary radiation exposure. Low dose and ultra-low-dose CT remain the diagnostic standard for most populations but remain underutilized. Single and dual-energy CT provide three-dimensional imaging that can predict stone-specific parameters that help clinicians predict stone passage likelihood, identify ideal management techniques, and possibly reduce complications. Machine learning has been increasingly applied to 3-D imaging to support clinicians in these prognostications and treatment selection.

SUMMARY

The diagnosis and management of urolithiasis are increasingly personalized. Patient and stone characteristics will support clinicians in treatment decision, surgical planning, and counseling.

Ureteral wall thickness is an independent parameter affecting the success of extracorporeal shock wave lithotripsy treatment in ureteral stones above the iliac crest

BACKGROUND

To investigate the relationship between ureteral wall thickness (UWT) and other variables of patients who underwent extracorporeal shock wave lithotripsy (SWL) in the primary treatment of the ureteral stone above the iliac crest level.

MATERIAL AND METHODS

A total of 147 patients aged 18 years and older, who underwent SWL in our clinic between December 2016 and December 2019 for the treatment of ureteral stones above the iliac crest level and had non-contrast enhanced abdominal computed tomography scans before the procedure were included in the clinical study. The results were evaluated at 3 months after SWL. The absence of residual fragments was considered as stone-free status, and the existence of any size residual fragment was considered as treatment failure.

RESULTS

In our study, the mean age of the patients was 42.4 ± 12.8 years, and the stone-free rate was 92.5%. The median transverse stone size was 7.5 mm (min 2.8-max 15), and the median UWT was 4.2 mm (1-8.7). In the multivariate analysis, UWT (P = .002) and multiple stone presence (P = .027) were found to be independent factors affecting stone-free status. In the receiver operating characteristic curve analysis, the optimal threshold value for UWT was determined as 5.25 mm.

CONCLUSIONS

We found that UWT was the most important independent variable associated with increased failure in SWL treatment. The presence of multiple stones was another independent factor that increased the failure rates. Using SWL technology through experience accumulated with the mechanical hardware of the machine, we can select patients who are more suitable for this treatment and improve treatment outcomes.

Histogram of kidney stones on non-contrast computed tomography to predict successful stone dusting during retrograde intrarenal surgery

PURPOSE

To predict successful dusting of kidney stones during retrograde intrarenal surgery (RIRS) using stone density parameters and histograms measured with non-contrast computed tomography imaging.

METHODS

Medical records of 49 patients who underwent retrograde intrarenal surgery between January 2018 and January 2019 at Kyung Hee University Hospital were reviewed, and the data of 55 stones were evaluated. Patient age, sex, mean stone density, the highest and lowest measured Hounsfield unit (HU), standard deviation and range of the measured HUs, volume of the most measured HU, and success of dusting were evaluated. Histograms of the measured HUs were created and cutoff values for successful dusting were analyzed.

RESULTS

Thirty-two stones were successfully dusted during surgery. Dusted stones had a wider range of HU and higher standard deviation. The volume of the most measured HU was smaller in the dusted stones. Successful dusting could be predicted when the volume of the most measured HU was < 8.9 mm³, with range ≥ 853, or when the volume of the most measured HU was < 8.9 mm³, with range < 853, and the mean stone density was < 355. The histograms of HUs of the dusted stones were wide and rugged, while those of dusting failed stones were narrow and peaked.

CONCLUSION

Evaluation of stone HU histograms showed differences in distribution and proportion. This will help predict surgical outcomes and prepare for intraoperative complications.

The Impact of Stone Density on Operative Complications of Retrograde Intrarenal Surgery: A Multicenter Study with Propensity Score Matching Analysis

Background: The aim of the study was to evaluate the impact of stone density on operative complication rates in retrograde intrarenal surgery (RIRS). Materials and Methods: A total of 473 consecutive patients undergoing RIRS for the treatment of upper tract urinary stones were included. To adjust for baseline confounders, one-to-one propensity score matching was performed. After matching, the patients were divided into two groups according to stone density (low density [LD] group, ≤970 Hounsfield unit [HU]; high density [HD] group, >970 HU). The patients' demographics, stone-related features, stone-free rates, and intraoperative and postoperative complication rates were compared between the groups. The primary objective was to evaluate whether the intraoperative and postoperative complication rates were higher in patients whose stone density was greater than 970 HU. Results: After propensity score matching, 170 of 210 LD and 170 of 263 HD patients undergoing RIRS were included. The baseline characteristics did not differ significantly between the groups. There were no significant differences between LD and HD patients with respect to intraoperative (5.9% and 8.8%, respectively; P = .29), postoperative (10.6% and 15.3%, respectively; P = .14), and overall complication rates (15.2% and 21.1%, respectively; P = .16). Stone-free status was achieved in 143 patients (84.1%) in the LD group and 148 patients (87%) in the HD group; the difference was not statistically significant (P = .27). Conclusion: Our results show that RIRS is a safe and effective minimally invasive procedure for the treatment of upper urinary tract stones, even in HD stones.