Cavitation-induced pressure saturation: a mechanism governing bubble nucleation density in histotripsy

Objective.Histotripsy is a noninvasive focused ultrasound therapy that mechanically disintegrates tissue by acoustic cavitation clouds. In this study, we investigate a mechanism limiting the density of bubbles that can nucleate during a histotripsy pulse. In this mechanism, the pressure generated by the initial bubble expansion effectively negates the incident pressure in the vicinity of the bubble. From this effect, the immediately adjacent tissue is prevented from experiencing the transient tension to nucleate bubbles. Approach.A Keller-Miksis-type single-bubble model was employed to evaluate the dependency of this effect on ultrasound pressure amplitude and frequency, viscoelastic medium properties, bubble nucleus size, and transducer geometric focusing. This model was further combined with a spatial propagation model to predict the peak negative pressure field as a function of position from a cavitating bubble.Main results. The single-bubble model showed the peak negative pressure near the bubble surface is limited to the inertial cavitation threshold. The predicted bubble density increased with increasing frequency, tissue viscosity, and transducer focusing angle. The simulated results were consistent with the trends observed experimentally in prior studies, including changes in density with ultrasound frequency and transducerF-number.Significance.The efficacy of the therapy is dependent on several factors, including the density of bubbles nucleated within the cavitation cloud formed at the focus. These results provide insight into controlling the density of nucleated bubbles during histotripsy and the therapeutic efficacy.

Comparing Same-Sitting Bilateral vs Unilateral Retrograde Intrarenal Surgery in the Elderly

OBJECTIVE

To compare same-sitting bilateral vs unilateral retrograde intrarenal surgery (RIRS) in elderly patients, focusing on postoperative complications and stone-free rates (SFR).

METHODS

Data from 2 multicenter databases, FLEXible ureteroscopy Outcomes Registry (FLEXOR) (unilateral RIRS) and same sitting bilateral-retrograde intrarenal surgery (SSB-RIRS) (bilateral RIRS), were analyzed, considering only patients aged 70+ with preoperative computed tomography. Patients were categorized into Group 1 (bilateral RIRS) and Group 2 (unilateral RIRS). Follow-up included imaging assessments and secondary treatments as needed.

RESULTS

Group 1 included 146 patients, while group 2 had 495. Group 1's patients were slightly older and had a higher prevalence of recurrent stone formation. Group 2 often underwent RIRS for incidental stones. Group 1 had larger and more pelvic stones. Laser lithotripsy and total operation times were significantly longer in Group 1. Group 2 had significantly higher overall stone-free rates, although there were no significant differences in ancillary procedures for residual fragments. Group 1 experienced more pelvicalyceal injuries needing stenting, postoperative fever, and post-op hematuria not requiring transfusion.

CONCLUSION

In conclusion, bilateral RIRS can be carefully considered in elderly patients. Preoperative counseling is essential for both primary and repeat RIRS procedures, and further research is needed to optimize instrument and laser strategies for better outcomes in elderly RIRS patients.

Holmium:YAG laser-assisted intraductal sialendoscopic lithotripsy under local anesthesia

OBJECTIVES

This retrospective multi-institutional chart review study aims to present results from patients treated with Holmium:YAG laser-assisted sialendoscopic intraductal lithotripsy under local anesthesia.

METHODS

Preoperative ultrasound and/or CT were used for location and measurement of the stones. Local anesthesia was applied in all patients, Marchal all-in- one 1.3 mm and Erlangen 1.6 sialendoscopes were used. The laser was used with power settings limited by discomfort or pain. Inclusion criteria were stone size (all >5 mm) and fixed stones.

RESULTS

42 patients, 48 stones were treated (30 males/12 females), 21 submandibular and 21 parotid. Ages ranged from 20 to 70 years (95 % CI: 43.37-51.58). Mean size was 6.2 mm (95 % CI: 5.71-6.72). Complete fragmentation was achieved in 66.7 % and incomplete in 33.3 %. Out of the incomplete fragmented 14 cases, seven (50 %) remained symptom free on follow-up. Maximum duration was 120 min. Minimum power settings of the laser was 4.8 Watts and maximum 18 Watts. Six patients expressed pain or discomfort that limited power increase and duration of the procedure. Total follow up time was 10 years. There were no major complications such as hemorrhage, nerve paresis or skin ulceration.

CONCLUSION

The procedure is safe under local anesthesia, well tolerated by most patients and should be used in cases of small fixed and "intermediate-sized" stones as a single modality. Discomfort may limit power settings and duration. The later is the major disadvantage of the method.

One and done: Feasibility and Safety of Primary Ureteroscopy in a Pediatric Population

BACKGROUND

Pediatric urolithiasis has been increasing at rate of 4-10 % annually in the United States, most notably within adolescents and females. A significant number of patients will require surgical management of their stones. Primary ureteroscopy (URS) affords the opportunity to treat stones under a single anesthetic with lower re-treatment rates or anatomical and stone characteristic limitations compared to shockwave lithotripsy. Previous studies evaluating primary URS have been largely underpowered, are limited by stone location, and/or are not representative of the stone population in the United States.

OBJECTIVES

Primary study outcomes were the success of primary URS and patient characteristics associated with success. Secondary outcomes were the stone-free rate (SFR), 30-day emergency department (ED) visits, 30-day readmissions, and complications.

METHODS

We performed a retrospective cohort study of patients less than 18 years of age from 2011 to 2023 who underwent primary URS. Patients were excluded if a ureteral stent was placed prior to URS or diagnostic URS was performed. A successful primary URS was considered if access to the ureter was obtained and treatment of the stone(s) completed. In failed primary URS, a ureteral stent was placed for staged management.

RESULTS

A total of 196 patients were included and primary URS was performed or attempted on 224 renal units. The median age was 15.8 (IQR 13.4-16.9) years and median follow up 8.4 (IQR 1.1-24.6) months. The success rate of primary URS was 79 %. No significant characteristics were appreciated for successful primary URS based on: overall age, <14 vs > 14 years of age, sex, body mass index, history of stones, history of endourologic procedures, preoperative alpha blockade, location of stone(s), multiple stones, type of URS, or acute treatment. In successful primary URS, the SFR was 88 % with stone size (p = 0.0001) the only predictor of having residual stones. The 30-day ED rate was 21.4 %, 30-day unplanned readmission rate was 12.5 %, and complication rate was 7.5 %. No long-term complications were appreciated.

DISCUSSION

Our success of primary URS compares favorably to previously published literature. Our SFR rate, 30-day ED visits, 30-day unplanned readmission, and complication rates are similar to other studies. Limitations of the study are its retrospective design, selection bias, and intermediate follow-up.

CONCLUSIONS

Primary URS can be completed safely in the majority of pediatric patients without any patient characteristics associated with success. We advocate for primary URS when possible due to the excellent SFR and potential of treating stones under a single anesthetic.

Optimizing targeting strategies for lithotripsy through in-vitro and in vivo studies with consideration of respiratory regularity

BACKGROUND

This work aimed to identify a method to achieve improved stone targeting and safety in shockwave lithotripsy by accounting for respiration.

METHODS

We set up an electromotive device simulating renal movement during respiration to place artificial stones within the phantom gel, measuring stone weight changes before and after shockwave exposure and the cavitation damage. We conducted clinical trials using respiratory masks and sensors to monitor and analyze patient respiration during shockwave lithotripsy.

RESULTS

The in vitro efficiency of lithotripsy was higher when adjusted for respiration than when respiration was not adjusted for. Slow respiration showed the best efficiency with higher hit rates when not adjusted for respiration. Cavitation damage was also lowest during slow respiration. The clinical study included 52 patients. Respiratory regularity was maintained above 90% in regular respiration. When respiration was regular, the lithotripsy rate was about 65.6%, which stayed at about 40% when respiration was irregular. During the lithotripsy, the participants experienced various events, such as sleep, taking off their masks, talking, movement, coughing, pain, nervousness, and hyperventilation. The generation of shockwaves based on respiratory regularity could reduce pain in patients.

CONCLUSION

These results suggest a more accurate lithotripsy should be performed according to respiratory regularity.

Cost-effectiveness of quality improvement intervention to reduce time between CT-detection and ureteroscopic laser fragmentation in acute symptomatic ureteric stones management

OBJECTIVE

To prospectively assess clinical and cost effectiveness of emergency ureteroscopic laser fragmentation of urinary stones causing symptoms or obstruction.

PATIENTS AND METHODS

100 consecutive patients with an average (median) age 55.6 (57.5) years and average (median) stone size of 8.2 mm (± 7 mm) between October 2018 and December 2021 who underwent emergency ureteroscopy and laser fragmentation formed the study cohort as part of a clinical service quality improvement. Primary outcome was single procedure stone-free rate and cost-effectiveness. The secondary outcomes were complications, re-admission and re-intervention. A decision analysis model was constructed to compare the cost-effectiveness of emergency ureteroscopy with laser fragmentation (EUL) and emergency temporary stenting followed by delayed ureteroscopy with laser fragmentation (DUL) using our results and success rates for modelling.

RESULTS

Single procedure stone-free rates (SFR) for EUL and DUL were 85%. The re-intervention rate, re-admission and complication rates of the study cohort (EUL) were 9%, 18%, and 4%, respectively, compared to 15%, 20%, and 5%, respectively for the control cohort (DUL). The decision analysis modelling demonstrated that the EUL treatment option was more cost-efficient, averting £2868 (€3260) per patient for the UK health sector. Total cost of delayed intervention was £7783 (€8847) for DUL in contrast to £4915 (€5580) for EUL.

CONCLUSIONS

Implementation of quality improvement project based on a reduction in CT detection-to-laser fragmentation time interval in acute ureteric obstruction or symptoms caused by stones had similar clinical effectiveness compared to delayed ureteroscopic management, but more cost-effective.

Comparison of lithotripsy methods during mini-PNL: is there a role for ballistic lithotripsy in the era of high-power lasers

BACKGROUND

For renal stones > 20 mm, percutaneous nephrolithotomy (PNL) offers the best stone clearance rates with acceptable complication rates. This study aimed to compare the efficiency of high-power holmium YAG laser and ballistic lithotripsy during mini-PNL.

METHODS

Data from 880 patients who underwent mini-PNL for renal stones was investigated retrospectively. The study utilized propensity score matching to create two groups: laser lithotripsy (n = 440) and ballistic lithotripsy (n = 440). The groups were matched based on stone size, Guy's stone score, and stone density. The main objectives of the study were to assess the stone-free rate (SFR), duration of surgery, and complication rates.

RESULTS

The average age of the population was 51.4 ± 7.1 years, with a mean stone size of 28.6 ± 8.3 mm and a mean stone density of 1205 ± 159 HU. There were no significant differences between the groups. The SFRs of the laser lithotripsy and ballistic lithotripsy were 92.5% and 90.2%, respectively (p = 0.23). The laser lithotripsy group had a notably shorter surgery time (40.1 ± 6.3 min) compared to the ballistic lithotripsy group (55.6 ± 9.9 min) (p = 0.03). Complication rates were similar (p = 0.67).

CONCLUSIONS

Our study shows that a high-power holmium YAG laser provides quicker operation time compared to ballistic lithotripsy. However, ballistic lithotripsy is still an effective and safe option for stone fragmentation during mini-PNL. In places where a high-power holmium YAG laser is not available, ballistic lithotripters are still a safe, effective, and affordable option for mini-PNL.

Ureterorenoscopy for stone disease in pregnancy: a literature review and update

PURPOSE OF REVIEW

Management of stone disease in pregnancy poses a challenge for all healthcare professionals involved in their care. During pregnancy, there is an increase in the incidence of urolithiasis. Major technological and procedural advances have been seen in the last decade for endoscopic management of urolithiasis. The purpose of this review is to provide a comprehensive workup of available literature on use of ureteroscopy for stone treatment during pregnancy.

RECENT FINDINGS

We identified 268 articles on screening, of which 28 were included in the final review. Overall adverse event rates were low, with no severe complications reported in the included studies. On multivariate analysis, the only significant correlation was an inverse relationship between calculated caseload and adverse obstetric events. No further correlation could be found between caseload, operation technique and adverse event rates. Data quality was low among the included studies.

SUMMARY

While ureteroscopy is a relatively safe and effective option for active stone treatment during pregnancy, they should be performed in experienced endourology centres in conjunction with obstetric teams.

Learning curve of ultrasound-guided percutaneous nephrolithotripsy in the treatment of complex renal calculi

OBJECTIVE

This study was performed to investigate the learning curve of ultrasound-guided percutaneous nephrolithotripsy (PCNL) for the treatment of complex renal calculi.

METHODS

Seventy-two patients with complex renal stones who underwent ultrasound-guided PCNL by the same operator from November 2016 to September 2020 were retrospectively analyzed. The learning curve of PCNL for complex renal stones was analyzed using multifactorial cumulative sum (CUSUM) analysis and best-fit curves.

RESULTS

The CUSUM best-fit curve peaked at Case 36, which represented the minimum number of cumulative cases required to cross the learning curve for this surgical procedure. Accordingly, the learning curve was divided into a learning improvement period (36 cases) and a proficiency phase (36 cases). Compared with the learning improvement period, the proficiency phase was characterized by a shorter puncture time and operation time, a smaller drop in the hemoglobin level, and a lower postoperative complication rate.

CONCLUSION

The learning curve of PCNL for the treatment of complex renal calculi can be divided into a learning improvement period and a proficiency phase, and the minimum cumulative number of cases is 36.

[Phytoprophylaxis of complications after extracorporeal lithotrips]

AIM

To evaluate the efficiency of the drug phytolysin (capsules) in the prevention of complications after extracorporeal lithotripsy.

MATERIALS AND METHODS

A total of 15 patients diagnosed with urolithiasis and chronic pyelonephritis in the latent phase were treated. The predominant localization of radiopaque stones no larger than 20 mm in size was the collecting system. The piezoelectric lithotripsy (1-2 sessions) was performed, followed by the administration of the herbal drug Phytolysin in the dosage form of a capsule. The follow-up was carried out after 14- and 30-days using laboratory, ultrasound and x-ray methods.

RESULTS

In the postoperative period, there were no cases of the pyelonephritis, which may result from a short-term disturbance of the upper urinary tract urodynamics due to the passage of stone fragments. The antibacterial, antispasmodic, diuretic and anti-inflammatory effects of Phytolysin ensured positive changes in laboratory and bacteriological tests, contributed to the prevention of postoperative complications after extracorporeal lithotripsy (renal colic, pyelonephritis), and contributed to maintaining renal blood flow within normal limits and significantly reduced the time to stone-free status.

CONCLUSIONS

Our results justify the feasibility of using phytolysin in capsules in patients with urolithiasis after extracorporeal lithotripsy. The dosage form in capsules eliminates the undesirable effects associated with the specific smell and taste, that patients noted when using phytolysin in the form of a paste.

[Comprehensive comparative assessment of the results of treatment of patients with ureteral stones using two different methods]

AIM

To improve treatment outcomes in patients with ureteral stones by optimizing the use of noninvasive and minimally invasive techniques.

MATERIAL AND METHODS

A prospective analysis of 186 patients with ureteral stones who were treated at the "RSSPMCU" in the period from July 2020 to April 2023 was carried out. Among them, 84 were undergone to electromagnetic extracorporeal shock-wave lithotripsy (ESWL) using the Storz Modulith SLX-F2 device (Switzerland). A procedure was performed under ataralgesia. The mean stone size was 8.54+/-2.79 (4-16 mm). The average amount of shock waves per stone was 2436+/-247.78. The session duration was 19.37+/-1.86 minutes. Endoscopic procedures were performed in 102 patients. Among them, 49 stones were removed using the ureteroscopy (URS), while in 49 and 4 cases percutaneous access (PCNL) and a combination of PCNL and URS under spinal anesthesia were done, respectively. The mean stone size was 11.46+/-4.26 (5-26 mm). Holmium laser or pneumatic lithotripsy was performed. The duration of the procedure was 63.38+/-17.48 min.

RESULTS

The stone density of patients undergoing ESWL was 855+/-319.84 HU, while those undergoing endoscopic procedures was 943.78+/-319.48 HU (p>0.05). The absorbed dose with ESWL was 18.73+/-4.15 mGy compared to 31.42+/-1.40 mGy for endoscopic procedures (p<0.001). A length of stay was 1.0+/-0.0 and 2.75+0.1, respectively (p<0.001). After 7-10 days, the stone free rate (SFR) was 76.2% (n=64) after ESWL and 99.02% (n=101) after endoscopic interventions (p<0.05). In the ESWL group, 3 patients received second session of ESWL for residual stones and in 9 cases URS was done. The SFR was 100% on day 45. In patients after endoscopic interventions, 1 patient underwent URS and SFR was 100% on the 15th day.

CONCLUSION

In general, the endoscopic technique is superior to ESWL in patients with ureteral stones both in terms of SFR and duration of procedure, but is inferior in safety due to invasiveness and the absorbed dose. In our opinion, the key indication for endoscopic treatment should be stone size greater than 6 mm, density more than 1000 HU, and patient preference.

Navigation systems and 3D imaging in percutaneous nephrolithotripsy: improving outcomes and safety

PURPOSE OF REVIEW

Percutaneous nephrolithotripsy (PCNL) is the first-line management option for large kidney stones (>2 cm). It remains, however, a demanding procedure with considerable morbidity. The present narrative review summarizes recent knowledge from original research studies investigating navigation systems/three-dimensional (3D) imaging in PCNL, particularly on publications during the past 12-18 months.

RECENT FINDINGS

Navigation systems and 3D imaging are primarily used for preoperative planning, with few intra-operative applications. Patient management and residents' training could benefit from their use.

SUMMARY

Navigation systems and 3D imaging technology have emerged as a potential game-changer in PCNL. Even though available evidence is currently scarce/inconclusive, the safety/efficacy of navigation systems and 3D dimensional imaging use in PCNL appears promising. This advanced technology offers precise anatomical mapping, improved visualization, and surgical accuracy. Enabling a comprehensive preoperative evaluation and improving guidance, navigation systems, and 3D imaging technology may improve the safety and efficacy of PCNL. With continuous technological evolution, it is expected that improvements/innovations will offer further aid in such demanding procedures. Familiarization and cost reduction are necessary for widespread application, while larger-scale prospective studies and well designed randomized controlled trials are still needed.

Is extracorporeal lithotripsy a first-line treatment for urinary stones today?

OBJECTIVE

To evaluate the efficacy and complications of extracorporeal lithotripsy (SWL) as a first-line treatment for renal and ureteral stones METHODS: Retrospective and observational study of all the patients treated with lithotripsy in a third level center between January 2014 and January 2021; characteristics of the patients, the stones, complications and results of SWL is recollected. Multivariate logistic regression of the factors associated with stone size reduction was performed. A statistical analysis of the factors associated with additional treatment after SWL and factors associated with complications is also executed.

RESULTS

1727 patients are included. Stone mean size was 9,5mm. 1540 (89.4%) patients presented reduction in stone size. In multivariate analysis, stone size (OR=1.13; p=0.00), ureteral location of the lithiasis (OR=1.15; p=0.052) and number of waves (p=0.002; OR=1.00) used in SWL are the factors associated with reduction of stone size. Additional treatment after lithotripsy was needed in 665 patients (38.5%). The factors associated with the need for retreatment were stone size (OR=1.131; p=0.000), number of waves (OR=1.000; p=0.000), energy (OR=1.005; p=0.000). 153 patients (8.8%) suffered complications after SWL. A statistically significant association was found between the size of the lithiasis (p=0.024, OR=1.054) and the previous urinary diversion (P=0.004, OR=0.571).

CONCLUSION

Lithotripsy remains an effective treatment as the first line of therapy for reno-ureteral lithiasis with a low percentage of complications.

The fate of clinically insignificant residual fragments following retrograde intrarenal surgery and factors affecting spontaneous passage

The remaining stone fragments after retrograde intrarenal surgery (RIRS) can lead to stone recurrence/regrowth, or stone-related events (SRE). We aimed to delineate the clinical circumstances that are decisive for spontaneous passage of clinical insignificant residual fragments (CIRF) (primary outcome) and define risk factors for stone recurrence/regrowth and their clinical manifestation (secondary outcome). A total of 115 patients who had CIRF following RIRS were included in this study. Demographic, clinical data, stone, and anatomic characteristics including infundibulopelvic angle (IPA), infundibular length (IL) and follow-up data of patients were analyzed. The mean follow-up time was 27.5 ± 6.9 months. 31 (26.9%) patients passed the CIRF spontaneously. Patients were divided into two groups as spontaneous fragment passage group and fragment remaining group and compared with respect to demographic, clinical, stone-related, and anatomic characteristics. 61.2% of patients had lower pole CIRF in fragment remaining group and 83.3% of patients in spontaneous fragment passage group (p = 0.031). In addition, IPA was wider in spontaneous fragment passage group (60.7° vs 51.4°, p = 0.001). A subanalysis was performed for fragment remaining group. In 84 patients, 44 (52.4%) patients were stable for their CIRF at their follow-up and included in stable group. 40 (47.6%) patients experienced stone re-growth (27 patients) or SRE (13 patients) at their follow up. Patients in re-growth/SRE group were older (49.1 vs 39.4 years, p = 0.047), had higher body mass index (28.2 vs 27 kg/m2, p = 0.03) and larger CIRF (2.8 vs 2.1 mm). CIRFs may be not expelled spontaneously and they may lead to additional morbidity and lithotripsy interventions.

Sex-specific analysis of intravascular lithotripsy for peripheral artery disease from the Disrupt PAD III observational study

OBJECTIVE

Endovascular therapy of lower extremity peripheral artery disease (PAD) is associated with higher complication rates and worse outcomes in women vs men. Although intravascular lithotripsy (IVL) has shown similarly favorable outcomes in men and women in calcified coronary arteries, there is no published safety and effectiveness data of peripheral IVL differentiated by sex. This study aims to evaluate sex-specific acute procedural safety and effectiveness following IVL treatment of calcified PAD.

METHODS

We performed a secondary analysis of the multicenter Disrupt PAD III Observational Study, which assessed short-term procedural outcomes of patients undergoing treatment of symptomatic calcified lower extremity PAD with the Shockwave peripheral IVL system. Adjudicated acute safety and efficacy outcomes were compared by sex using univariate analysis performed with the χ2 test or Fisher exact test, as appropriate.

RESULTS

A total of 1262 patients (29.9% women) were included, with >85% having moderate to severe lesion calcification. Women were older (74 vs 71 years; P < .001), had lower ankle-brachial index (0.7 vs 0.8; P = .003), smaller reference vessel size (5.3 vs 5.6 mm; P = .009), and more severe stenosis at baseline vs men (82.3% vs 79.8%; P = .012). Rates of diabetes, renal insufficiency, chronic limb-threatening ischemia, lesion length, and atherectomy use were similar in both groups. Residual stenosis after IVL alone was significantly reduced in both groups. Final residual stenosis was 21.9% in women and 24.7% in men (P = .001). Serious angiographic complications were infrequent and similar in both groups (1.4% vs 0.6%; P = .21), with no abrupt vessel closure, distal embolization, or thrombotic events during any procedure.

CONCLUSIONS

The use of IVL to treat calcified PAD in this observational registry demonstrated favorable acute safety and effectiveness in both women and men.

Effect of acupressure on pain intensity and physiological indices in patients undergoing extracorporeal shock wave lithotripsy: a randomized double-blind sham-controlled clinical trial

BACKGROUND

Despite the widespread use of extracorporeal shock wave lithotripsy (ESWL) as a treatment for kidney stones, it is essential to apply methods to control pain and improve patient comfort during this procedure. Therefore, this study aimed to investigate the effect of acupressure at the Qiu point on pain intensity and physiological indices in patients undergoing ESWL.

METHODS

This randomized, sham-controlled clinical trial was conducted at the Shahid Beheshti Educational-medical Center in Hamadan City (western Iran) from May to August 2023. Seventy-four eligible patients were split into intervention (n = 37) and sham (n = 37) groups. Ten minutes before lithotripsy, the intervention group received acupressure at the Qiu point, while the sham group received touch at a neutral point. The primary outcomes were pain intensity measured by the Visual Analog Scale (VAS) and physiological indices such as blood pressure and heart rate at baseline, 1, 10, 20, 30, 40, and 50 min after the intervention. The secondary outcomes included lithotripsy success and satisfaction with acupressure application.

RESULTS

The analysis of 70 patients showed no significant differences in the demographic and clinical information of the patients across the two groups before the study (P > 0.05). Generalized estimating equations revealed that the interaction effects of time and group in pain and heart rate were significant at 30 and 40 min (P < 0.05). The results of this analysis for systolic blood pressure revealed a significant interaction at 30 min (P = 0.035). However, no significant interaction effects were found for diastolic blood pressure changes (P > 0.05).

CONCLUSIONS

Acupressure at the Qiu point positively impacts pain in patients undergoing ESWL treatment and increases their satisfaction. However, these results for physiological indices require further studies. Thus, acupressure can be considered a simple, easy, and effective option for pain management in patients during this procedure.

TRIAL REGISTRATION

[ https://en.irct.ir/trial/69117 ], identifier [IRCT20190524043687N4].

Advancements in stone classification: unveiling the beauty of urolithiasis

PURPOSE

Urolithiasis has become increasingly prevalent, leading to higher disability-adjusted life years and deaths. Various stone classification systems have been developed to enhance the understanding of lithogenesis, aid urologists in treatment decisions, and predict recurrence risk. The aim of this manuscript is to provide an overview of different stone classification criteria.

METHODS

Two authors conducted a review of literature on studies relating to the classification of urolithiasis. A narrative synthesis for analysis of the studies was used.

RESULTS

Stones can be categorized based on anatomical position, size, medical imaging features, risk of recurrence, etiology, composition, and morphoconstitutional analysis. The first three mentioned offer a straightforward approach to stone classification, directly influencing treatment recommendations. With the routine use of CT imaging before treatment, precise details like anatomical location, stone dimensions, and Hounsfield Units can be easily determined, aiding treatment planning. In contrast, classifying stones based on risk of recurrence and etiology is more complex due to dependencies on multiple variables, including stone composition and morphology. A classification system based on morphoconstitutional analysis, which combines morphological stone appearance and chemical composition, has demonstrated its value. It allows for the rapid identification of crystalline phase principles, the detection of crystalline conversion processes, the determination of etiopathogenesis, the recognition of lithogenic processes, the assessment of crystal formation speed, related recurrence rates, and guidance for selecting appropriate treatment modalities.

CONCLUSIONS

Recognizing that no single classification system can comprehensively cover all aspects, the integration of all classification approaches is essential for tailoring urolithiasis patient-specific management.

Effects of pulse repetition frequency on bubble cloud characteristics and ablation in single-cycle histotripsy

Objective. Histotripsy is a cavitation-based ultrasound ablation method in development for multiple clinical applications. This work investigates the effects of pulse repetition frequency (PRF) on bubble cloud characteristics and ablative capabilities for histotripsy using single-cycle pulsing methods.Approach.Bubble clouds produced by a 500 kHz histotripsy system at PRFs from 0.1 to 1000 Hz were visualized using high-speed optical imaging in 1% agarose tissue phantoms at peak negative pressures,p-, of 2-36 MPa.Main results.Results showed a decrease in the cavitation cloud threshold with increasing PRF, ranging from 26.7 ± 0.5 MPa at 0.1 Hz to 15.0 ± 1.9 MPa at 1000 Hz. Bubble cloud analysis showed cavitation clouds generated at low PRFs (0.1-1 Hz) were characterized by consistently dense bubble clouds (41.7 ± 2.8 bubbles mm-2at 0.1 Hz), that closely matched regions of the focus above the histotripsy intrinsic threshold. Bubble clouds formed at higher PRFs measured lower cloud densities (23.1 ± 4.0 bubbles mm-2at 1000 Hz), with the lowest density measured for 10 Hz (8.8 ± 4.1 bubbles mm-2). Furthermore, higher PRFs showed increased pulse-to-pulse correlation, characteristic of cavitation memory effects; however, bubble clouds still filled the entire volume of the focus due to their initial density and enhanced bubble expansion from the restimulation of residual nuclei at the higher PRFs. Histotripsy ablation assessed through lesion analysis in red blood cell (RBC) phantoms showed higher PRFs generated lesions with lower adherence to the initial focal region compared to low PRF ablations; however, no trend of decreasing ablation efficiency with PRF was observed, with similar efficiencies observed for all the PRFs tested in this study.Significance.Notably, this result is different than what has previously been shown for shock-scattering histotripsy, which has shown decreased ablation efficiencies at higher PRFs. Overall, this study demonstrates the essential effects of PRF on single-cycle histotripsy procedures that should be considered to help guide future histotripsy pulsing strategies.

Place of urolithiasis in the spectrum of urological pathologies, practices and use of endourological procedures in the management of calculi of the upper urinary tract: results of a survey of referral centres in Africa

Our aim was to determine the current trend of endourology in the management of upper urinary tract calculi in Africa reference centres. We conducted an online multiple-choice questionnaire survey involving 46 centres from 27 countries using a structured well-designed Google Form (®) questionnaire. The questionnaires were distributed to the head of service through their emails. The questions collected demographic data about the centre, the epidemiology of urolithiasis, diagnostic means and management of upper urolithiasis, especially access to endourology procedures and their practices. Descriptive analyses were performed. The participation rate was 77.9%. Urinary lithiasis was one of the three main pathologies encountered in 42/46 centres. 33 centres had easy access to CT scanners and 34 had operating theatres equipped with endo-urological surgery equipment. Of these 34 centres, 30 perform endourology for the management of upper urinary tract stones. Rigid ureteroscopy is the main technique used by the centres. It is the only endourology technique used for stone management by 12 centres (40%). 7/30 (23.3%) have the option of performing rigid ureteroscopy, flexible ureteroscopy and percutaneous nephrolithotomy. The frequency of procedures varies widely, with 43.3% rarely performing endourological surgery. Seventeen centres have their operating theatre equipped with a fluoroscope and 6/42 centres have extracorporeal lithotripsy. Open surgery is still used in 29/42 centres (69.1%). Laparoscopy is available in 50% of centres, but none reported performing laparoscopic lithotomy. In Africa, urinary lithiasis plays an important role in the activities of referral centres. Modern management techniques are used to varying degrees (not all centres have them) and with very variable frequency. Open surgery is still widely performed as a management. Rigid ureteroscopy is the main endourological technique. It is essential to develop the practice of modern urology in Africa, mainly endourology.

How to estimate stone volume and its use in stone surgery: a comprehensive review

OBJECTIVE

Current interventional guidelines refer to the cumulative stone diameter to choose the appropriate surgical modality (ureteroscopy [URS], extracorporeal shockwave lithotripsy [ESWL] and percutaneous nephrolithotomy [PCNL]). The stone volume (SV) has been introduced recently, to better estimate the stone burden. This review aimed to summarize the available methods to evaluate the SV and its use in urolithiasis treatment.

MATERIAL AND METHODS

A comprehensive review of the literature was performed in December 2022 by searching Embase, Cochrane and Pubmed databases. Articles were considered eligible if they described SV measurement or the stone free rate after different treatment modalities (SWL, URS, PCNL) or spontaneous passage, based on SV measurement. Two reviewers independently assessed the eligibility and the quality of the articles and performed the data extraction.

RESULTS

In total, 28 studies were included. All studies used different measurement techniques for stone volume. The automated volume measurement appeared to be more precise than the calculated volume. In vitro studies showed that the automated volume measurement was closer to actual stone volume, with a lower inter-observer variability. Regarding URS, stone volume was found to be more predictive of stone free rates as compared to maximum stone diameter or cumulative diameter for stones >20 mm. This was not the case for PCNL and SWL.

CONCLUSIONS

Stone volume estimation is feasible, manually or automatically and is likely a better representation of the actual stone burden. While for larger stones treated by retrograde intrarenal surgery, stone volume appears to be a better predictor of SFR, the superiority of stone volume throughout all stone burdens and for all stone treatments, remains to be proven. Automated volume acquisition is more precise and reproducible than calculated volume.

Retrospective study of single-use digital flexible ureteroscopic lithotripsy versus miniaturized percutaneous nephrolithotomy for 1.5-2.5cm lower pole renal stones

PURPOSE

Retrospective analysis was performed on the clinical information of patients with 1.5-2.5 cm lower pole renal stones treated by single-use digital flexible ureteroscopic lithotripsy (fURS) and miniaturized percutaneous nephrolithotomy (MPCNL) in affiliated hospital of the Nantong University from January 2020 to December 2022. To compare the safety and efficacy of single-use fURS and MPCNL in the treatment from 1.5cm to 2.5cm lower pole renal stones.

METHODS

Clinical information of 141 patients were collected and divided into single-use fURS group and MPCNL group according to their treatment methods, including 83 patients in the single-use fURS group and 58 patients in the MPCNL group. Baseline data, data on the clinical characteristics of stones, laboratory examination data, operation time, and postoperative data of the two groups were collected. Statistical analysis was made on the collected data to analyze the differences and causes between the two groups of patients.

RESULTS

There was no significant difference in the baseline data and preoperative clinical features of 141 patients between the two groups (P > 0.05). In comparison of postoperative serum indexes, the drop values of hemoglobin and creatinine in single-use fURS group were lower than those in MPCNL group, and the difference was statistically significant (P < 0.05). The stone free rate was higher in the MPCNL group than in the single-use fURS group on the first day after surgery. At the 1st month after surgery, the two groups were similar. At 3rd month after surgery, the single-use fURS group was slightly higher than the MPCNL group, with no statistical significance (P > 0.05). The total complication rate in single-use fURS group was slightly lower than that in MPCNL group, but there was no statistical significance (P > 0.05).

CONCLUSIONS

Single-use fURS has similar safety and efficacy to MPCNL in the treatment of 1.5-2.5cm lower pole renal stones. Single-use fURS may be a new option for the treatment of these stones.

Technological innovations in shock wave lithotripsy

INTRODUCTION

Since 1980, extracorporeal shock wave lithotripsy (SWL) has been employed in the treatment of urolithiasis, offering noninvasive alternatives to surgical techniques. In addition to being limited by the size and location of the stones, its efficacy is influenced by several factors. Despite the advancement of other surgical techniques, SWL could maintain its position with new improvements. Our objective is to review the existing literature on the latest advances in the extracorporeal treatment of lithiasis.

MATERIAL AND METHODS

A non-systematic literature review was carried out from 2017 to 2023 to obtain 26 articles on three different emerging technologies in extracorporeal lithotripsy: Burst Wave Lithotripsy (BWL), Histotripsy, and Microbubble Lithotripsy (ML).

RESULTS

The BWL uses sinusoidal bursts of US waves delivered at lower and higher frequencies than conventional SWL. Its mechanism of action generates a higher quality fragmentation (fine fragments) instead of generating tensile stresses for stone fracture resulting in larger fragments, as in traditional SWL. Studies in pigs and humans have shown effective fragmentation with a good safety profile. Based on High Intensity Focused Ultrasound (HIFU) technology, histotripsy fragments tissue through cavitation. Good in vitro results have been shown, but the formation of microbubbles between the stone and ultrasound waves hinders the progress of this technique. Microbubble Lithotripsy (ML) combines microbubbles and ultrasound for safe and effective stone fragmentation. In vitro and pig results are promising. This technique can help optimize treatments and reduce energy levels.

CONCLUSIONS

Technological innovation is not only being applied to endourological techniques, but also to ESWL. New techniques such as BWL, histotripsy and ML are promising, with good results in the research phase.

The influence of perioperative nursing intervention in patients with ureteral calculi treated with URSL and its correlation to adverse event incidence: A retrospective study

To evaluate the effectiveness of perioperative nursing intervention in patients undergoing ureteroscopic lithotripsy (URSL) for ureteral stones and its implications for the incidence of adverse events, a total of 144 patients with ureteral stones admitted to our hospital from January 2021 to December 2022 were selected for retrospective analysis. They were divided into 2 groups based on their different nursing methods, with 72 patients in each group. The control group (CG) received routine nursing intervention, while the study group (SD) received refined perioperative nursing intervention. The surgical situation, effective stone removal rate, postoperative pain, inflammatory factors, stress response, and incidence of adverse events were compared between the 2 groups. In comparison with the CG, the SD demonstrated a significant reduction in gastrointestinal recovery time, urinary catheter removal time, and hospitalization duration, all presenting statistically significant disparities (P < .05). Notably, the SD exhibited a one-time stone removal rate significantly superior to that of the CG (P < .05). Similarly, the postoperative pain index was significantly lower in the SD (P < .05). Pre- and post-surgical serotonin (5-HT) levels in the SD were markedly lower than in the CG (P < .05). Postoperative levels of Interleukin-10 (IL-10), C-reactive protein (CRP), and white blood cells (WBC) were elevated in both groups, and gradually declined as the patients recovered. However, postoperative levels of IL-10, CRP, and WBC were significantly lower in the SD (P < .05). The SD also showed significantly lower levels of malondialdehyde and higher levels of superoxide dismutase (P < .05). Postoperative levels of cortisol, adrenocorticotropic hormone, and norepinephrine were elevated and progressively returned to normal over time, and were significantly lower in the study group (P < .05). Furthermore, the SD experienced a significant reduction in adverse event incidence compared with the CG (P < .05). Implementing refined perioperative nursing interventions for patients undergoing URSL can effectively decrease the incidence of adverse events, diminish the surgical stimulation of inflammation markers and oxidative stress indicators, and foster patient recovery.

AI prediction of extracorporeal shock wave lithotripsy outcomes for ureteral stones by machine learning-based analysis with a variety of stone and patient characteristics

We propose an artificial intelligence prediction method for extracorporeal shock wave lithotripsy treatment outcomes by analysis of a wide variety of variables. We retrospectively reviewed the records of 171 patients from between January 2009 and November 2019 that underwent shock wave lithotripsy at Wakayama Medical University, Japan, for ureteral stones shown on preoperative non-contrast computed tomography. This prediction method consisted of stone area extraction, stone analyzing factor extraction from non-contrast computed tomography images, and shock wave lithotripsy treatment result prediction by a non-linear support vector machine for analysis of 15 input and automatic measurement factors. Input factors included patient age, skin-to-stone distance, and maximum ureteral wall thickness, and the automatic measurement factors included 11 non-contrast computed tomography image texture factors in the stone area and stone volume. Permutation feature importance was also applied to the artificial intelligence prediction results to analyze the importance of each factor relating to estimate decision grounds. The prediction performance was evaluated by five-fold cross-validation, it obtained 0.742 of the mean area under the receiver operating characteristic curve. The proposed method is shown by these results to have robust data diversity and effective clinical application. As a result of permutation feature importance, some factors that showed high p-values in the significant difference tests were thought to have a high contribution to the proposed prediction method. Future issues include validation using a larger volume of high-resolution clinical non-contrast computed tomography image data and the application of deep learning.

Emergency treatment of symptomatic ureteral calculi: predictors of prolonged hospital stay

PURPOSE

To assess differences in the length of hospital stay (LOS) in patients who present emergently versus electively for a symptomatic ureteral stone and to explore underlying risk factors.

METHODS

Billing data were analyzed from patients with symptomatic ureteral calculi at our department from 2010 to 2021. Statistical analysis (U test, logistic regression) was performed.

RESULTS

2274 patients (72% male, 28% female) with ureteral stones were analyzed (mean age of 52.9y). 1578 patients (69.4%) presented in an emergency setting and 696 patients (30.6%) electively. Arterial hypertension was seen in 31%, diabetes mellitus in 11% and hyperuricemia in 5% of the whole cohort. 46.5% of emergency patients were desobstructed (DJ/PCN), 35.4% underwent emergency ureteroscopy (URS), 13.4% had spontaneous passage (SP), and 4.8% underwent emergency shock wave lithotripsy (SWL). Of the electively treated patients, 58.6% underwent URS, 21.3% SWL, 18.5% DJ/PCN, and 1.6% had SP. Emergency stone treatment was associated with a significantly longer LOS when compared to primary desobstruction for patients admitted emergently. Also, LOS was significantly longer for each intervention of stone treatment in emergency patients vs. electively treated patients. Arterial hypertension was associated with a 1.8-fold increased risk of a hospital stay longer than 3 days, irrespective of hospital admission mode, whereas metabolic disorders did not influence LOS in this cohort.

CONCLUSION

For emergency patients in contrast to the electively treated patients, the type of procedure had a significant impact on the length of hospital stay. Arterial hypertension is an independent significant risk factor for prolonged hospital stay.

Timing of ERCP after extracorporeal shock wave lithotripsy for large main pancreatic duct stones

BACKGROUND AND AIMS

Extracorporeal shock wave lithotripsy (ESWL) is performed to fragment large main pancreatic duct (MPD) stones in symptomatic patients. Subsequent endoscopic retrograde cholangiopancreatography (ERCP) is often performed to clear the stone fragments. Edema of surrounding tissue after ESWL theoretically affects the ability to perform ERCP. However, the optimal timing of ERCP after ESWL is not clearly defined. The aim of this study is to determine the efficacy and safety of same-day ERCP after ESWL and to determine if the timing of ERCP after ESWL affects outcomes.

METHODS

This is a retrospective study of consecutive patients from January, 2013 to September, 2019 who received ESWL for MPD stones at our center. Included patients received subsequent same-day ERCP under the same general anesthesia session or later session ERCP (1-30 days after ESWL). Demographics, anatomical findings, history, and outcomes were collected. Success was defined as complete or near complete (> 80%) stone fragmentation with clearance.

RESULTS

218 patients were treated with ESWL and subsequent ERCP. 133 (61.0%) received ERCP on the same day immediately after ESWL, while 85 (39.0%) returned for ERCP at a later day (median 3.0 days after ESWL). Baseline characteristics demonstrated patients who received same-day ERCP had a higher rate of pain at baseline (94.7% vs 87.1%, p = 0.045). Main outcomes demonstrated an overall successful MPD stone clearance rate of 90.4%, with similar rates between same-day ERCP and later session ERCP (91.7% vs 88.2%, p = 0.394). Additionally, successful cannulation at ERCP, adverse events, and post-procedure admission rates were similar.

CONCLUSIONS

Delaying ERCP to allow peripancreatic tissue recovery after ESWL does not affect outcomes. Same-day ERCP after ESWL is safe and effective.

Is stone free status really necessary for metabolic evaluation following stone removal procedures?

OBJECTIVE

To evaluate the impact of stone free status on the outcomes of metabolic evaluation in recurrent stone formers after ureteroscopic stone removal.

PATIENTS AND METHODS

A total of 78 patients undergoing retrograde intrarenal surgery (RIRS) for renal stones were included and cases were divided into two groups after 4 weeks based on the NCCT findings. While cases in the Group 1 (n = 54) was completely stone free, cases in Group 2 (n = 24) had residual fragments in the kidney. A full 24-h urine analysis for relevant stone forming risk factors has been performed after 4 weeks following the fURS procedures in all patients of both groups. Outcomes of metabolic evaluation (24-h urine and serum) have been comparatively evaluated in both groups.

RESULTS

Evaluation of the preoperative serum and urine stone forming risk factors revelaed no statistical difference in both groups. Comparative evaluation of the 24-h urinary stone forming risk factors also revealed no statistically significant difference between preoperative and postoperative findings in cases of Group 2 with residual stones. Last but not least, no significant difference was observed between the mean preoperative and postoperative serum variables between two groups.

CONCLUSIONS

Our results show that in the light of the similar metabolic evaluation outcomes obtained in cases with and without residual fragments, 'stone free status' may not be an essential factor to perform a detailed metabolic evaluation (24-h urine analysis and serum parameters) after endourological stone removal procedures.

Modified telescopic sheath method for exchange of luminally encrusted ureteral stents

A novel telescopic access sheath technique has been described to maintain access to the ureter in cases of stent encrustation, placing a suture on the externalised distal end of the stent followed by advancing a sheath over to peel off encrustations and maintain access in the ureter, as well as application of this technique in a child. Herein we present a modification of the telescopic sheath technique that allows exchange of luminally encrusted stents without requiring passage of the sheath into the ureter or ureteroscopy alongside the stent.

Comparison of immediate versus post-stenting ureteroscopy for ureteral stones treatment

Ureteroscopy is a highly effective treatment for ureteral stones, characterized by a high stone-free rate and a low need for re-treatment. Ureteral stent placement can improve the insertion of the ureteral access sheath and ureteroscope but may be associated with higher morbidity prior to and after ureteroscopy. The study aimed to compare immediate versus post-stenting ureteroscopy for ureteral stone treatment in terms of operative time, intra- and post-operative complications, length of hospital stay, and stone-free rate. This prospective study involved 126 patients with ureteral stones divided into two groups: the post-stenting ureteroscopy group (PS-URS), who underwent primary ureteral stenting by double J followed by delayed ureteroscopy, and the immediate ureteroscopy group (I-URS), who underwent immediate ureteroscopy without previous stenting. Sixty-six patients were included in the PS-URS group and 60 patients in the I-URS group. Results were comparable, with no significant differences between both groups. The mean operative time was 33.77±3.51 minutes for the PS-URS group and 34.60±2.01 minutes for the I-URS group. The average length of hospital stay was 0.84±2.55 days for PS-URS and 0.92±1.96 days for I-URS patients. The stone-free rate was 97% in the PS-URS group and 95% in the I-URS group. The overall complication rate was 4.5% versus 5% in the PS-URS and I-URS groups, respectively, with all complications being minor and managed effectively. Immediate ureteroscopy is a safe and relevant operative approach for ureteral stones, with comparative results for post-stenting delayed ureteroscopy.

Midterm Results of Intravascular Lithotripsy for Severely Calcified Common Femoral Artery Occlusive Disease: A Single-Center Experience

PURPOSE

Common femoral artery (CFA)-occlusive disease has traditionally been treated with open surgery, yet nowadays the frailty of patients has induced to find new techniques of revascularisation by endovascular means. So far, intravascular lithotripsy (IVL) has shown promising results in several lower limbs arterial districts. The purpose of this article is to report our experience with IVL for severely calcified peripheral arterial disease (PAD) of the CFA.

METHODS

From November 2018 and October 2020, 10 consecutive patients (12 limbs) treated with IVL were prospectively enrolled in a dedicated database. Inclusion criteria were CFA localization of PAD, with a severe degree of calcification, a lesion length ≥10 mm, and a degree of stenosis ≥70% (severe). The only admitted adjunctive treatment was drug-coated balloon (DCB) angioplasty. Primary outcomes were technical and procedural success, clinical success, and target lesion revascularisation (TLR). Secondary outcomes were target extremity revascularisation (TER) and major adverse events (MAEs).

RESULTS

All patients underwent IVL with associated DCB angioplasty. The median percentage of achieved stenosis reduction was 55.5% (interquartile range [IQR] 50-60.75), with a technical and procedural success of 100%. Over the study period, TLR only occurred in one limb (8.3%), with a mean upgrade in Rutherford class of 2.7 ± 0.77. No target vessel and access site complications were reported, as well as no distal embolization. One death and one major amputation occurred over the follow-up period, both in the same patient.

CONCLUSIONS

Based on our experience, IVL for selected cases of severely calcified CFA disease, associated with DCB angioplasty, may be considered a safe and effective technique. Of course, a long-term follow-up and a larger series of patients are needed to validate our results.

Comparative Study of Histotripsy Pulse Parameters Used to Inactivate Escherichia coli in Suspension

OBJECTIVE

Bacterial loads can be effectively reduced using cavitation-mediated focused ultrasound, or histotripsy. In this study, gram-negative bacteria (Escherichia coli) in suspension were used as model bacteria to evaluate the effectiveness of two regimens of histotripsy treatments: cavitation histotripsy (CH) and boiling histotripsy (BH).

METHODS

Ten-milliliter volumes of Escherichia coli were treated at different negative focal pressure amplitudes and over time periods up to 40 min. Cavitation activity was characterized with coaxial passive cavitation detection (PCD) and synchronized plane wave B-mode imaging.

RESULTS

CH treatments exhibited a threshold behavior that was consistent with PCD metrics of cavitation. Above the threshold, bacterial inactivation followed a monotonically increasing log-linear relationship that indicated an exponential inactivation rate. BH exhibited no threshold, but instead followed a different monotonically increasing inactivation rate. Inactivation rates were larger for BH at or below the CH threshold, and larger for CH substantially above the threshold. CH studies performed at different pulse lengths at the same duty cycle had similar inactivation rates, suggesting that at any given pressure amplitude, the "on time" was the most important variable for inactivating E. coli. The maximum inactivation was produced by CH at the highest pressure amplitudes used, leading to a log reduction >4.2 for a 40 min treatment.

CONCLUSION

The results of this study suggest that both CH and BH can be used to inactivate E. coli in suspension, with the optimal regimen depending on the attainable peak negative focal pressure at the target.

Intravascular lithotripsy for severely calcified carotid artery stenosis - A new frontier in carotid artery stenting?

Carotid stenosis due to severely calcified plaque can pose a significant therapeutic challenge. Extremely calcified scars/stenosis plaques can be challenging from an endovascular treatment perspective as severely calcified lesions are prone to technical failure, stent re-coil and restenosis. Intravascular lithotripsy, approved for treatment of severely calcified coronary lesions, can be used for breaking up the calcium build up in the intimal and medial layers of the vessel wall prior to stenting. This was designated as a breakthrough device innovation by the Food and Drug Administration. This new technique addresses the challenge of the disease without compromising patient safety during the procedure. We here report procedural set-up, execution and early patient follow up from our first use of this emerging technology in a neurointerventional practice setting.

Extracorporeal shock wave lithotripsy for lower calyx stones: predicting treatment success

INTRODUCTION

The use of extracorporeal shock wave lithotripsy (ESWL) for lower calyx stones is associated with a high rate of residual fragments. Our aim is to analyse the effectiveness and complications of ESWL for lower calyx stones.

METHODS

Retrospective review of patients with lower renal calyx stones treated with ESWL between January-2014 and December-2020. Measurement of infundibular length, infundibular width and infundibulopelvic angle in lower renal pole to determine favourable anatomy. ESWL failure: fragments >3 mm detected in plain abdominal film, CT scan and/or renal ultrasound 3 months after treatment. Complications after ESWL, auxiliary procedures along with risk factors associated with perirenal haematoma were analysed. SPSS statistical software was used.

RESULTS

512 patients with lower calyx stones were treated with ESWL. 80.3% of patients had a favourable anatomy. Overall stone-free rate was 70.5%. Regarding main complications after ESWL, stainstrasse was described in 5 patients and urinary tract infection in 3 patients. 10 perirenal haematomas (2%) were reported. Statistical association was found between antiplatelet treatment and the risk of perirenal haematoma (p = 0.004). Logistic binary regression proved the association between unfavourable anatomy of the lower renal pole (p = 0.000), size of the stone (p = 0.001), number of shock waves (p = 0.003), energy applied (p = 0.038) and the need for additional treatment after ESWL.

CONCLUSIONS

ESWL can still be considered as the initial treatment option for lower renal pole stones. The size of the stone, an unfavourable anatomy of the lower renal calyx, number of shock waves and energy applied can help predict the need for additional treatment.

A new position utilizing the effect of gravity in proximal ureteral stones, ureteroscopic lithotripsy in the reverse Trendelenburg position: a prospective, randomized, comparative study

PURPOSE

To evaluate the effect of the reverse Trendelenburg position in patients undergoing ureteroscopic lithotripsy for proximal ureteral stones.

METHODS

The study included 167 patients who underwent ureteroscopic lithotripsy for proximal ureter stones between December 2020 and September 2022. The patients were randomly assigned to one of three groups: standard lithotomy (n:55), 10° reverse Trendelenburg (n:55), and 20° reverse Trendelenburg (n:57). Preoperative information, including age, sex, body mass index (BMI), previous shock wave lithotripsy (SWL), stone side, volume, and density, distance to the ureteropelvic junction (UPJ) of the stone, and hydronephrosis degree. Stone-free status was evaluated with computed tomography (CT) at 4 weeks postoperatively. The groups were compared in respect of stone migration, stone-free rate, use of flexible ureterorenoscope, operating time, postoperative length of stay in the hospital, and complications.

RESULTS

No statistically significant difference was determined between the groups with respect to age, sex, BMI, previous SWL, stone side, volume and density, distance to the UPJ of the stone, and hydronephrosis degree (p > 0.05 for all). Statistically significant differences were determined between the groups with respect to stone migration (p = 0.001), stone-free rate (p < 0.001), use of flexible ureterorenoscope (p = 0.01), operating time (p < 0.001), hospital length of stay (p < 0.001), postoperative fever (p = 0.002), and total complications (p = 0.01).

CONCLUSION

A new patient position is presented in this study, which can be used in ureteroscopic lithotripsy performed for proximal ureteral stones. The reverse Trendelenburg position constitutes a surgical method that can be used safely and successfully in the treatment of proximal ureteral stones.

TRIAL REGISTRATION NUMBER

NCT04894058, 05/21/2021, Prospectively registered.

Urolithiasis: History, epidemiology, aetiologic factors and management

Urolithiasis is defined as a disease diagnosed by the presence of one or more stones in the urinary tract. It is one of the oldest and most widespread diseases known to man, their discovery and characterisation chronology began with the civilisation's history. This pathology has a multifactorial aetiology, very frequent worldwide with geographic and racial variation, their prevalence is increasing in lockstep with socioeconomic development. In fact, this disorder affects between 2 and 20% of the population, with an approximate recurrence rate of 30% to 50% in 5 years. Furthermore, calciumtype stones, which are composed of calcium oxalate (CaOx) alone or a mixture of CaOx and calcium phosphate are the most common, accounting for more than 80% of cases. The medical management of urolithiasis is done by medical treatments and/or by surgical intervention for the stones extraction by the techniques such as extracorporeal shock wave lithotripsy (ESWL), ureteroscopy (URS), percutaneous nephrolithotomy (PCNL) and open surgery. However, various therapies, including thiazide diuretics and alkaline citrate, are used in an attempt to prevent stones recurrence induced by hypercalciuria and hyperoxaluria, but the scientific evidence for their effectiveness is less convincing. On the other hand, endoscopic and ESWL methods have revolutionised the treatment of urinary lithiasis, but these costly methods, can cause acute kidney injury and decreased renal function, in addition, do not prevent the probability of new stone formation. The deepening of our knowledge on all points relating to this disease is a priority for specialists in order to find adequate solutions for this disease. This review provides an overview of urolithiasis, its history, epidemiology, clinical manifestation, diagnosis and treatment methods.

A population-based retrospective cohort study of surgical trends and outcomes of pediatric urolithiasis in Ontario, Canada (2002-2019)

INTRODUCTION

The worldwide incidence of pediatric urinary stone disease (PUSD) is increasing. However, there is no commensurate data on whether this translates to an increasing need for surgical intervention for PUSD, given the role of conservative management.

OBJECTIVE

We aimed to evaluate the trends and outcomes of clinically significant PUSD, using administrative databases to identify patients surgically treated for PUSD.

STUDY DESIGN

This retrospective population-based cohort study assessed the incidence and trends of surgically treated PUSD and outcomes in Ontario, Canada in patients <18 years of age who underwent their first PUSD procedure between 2002 and 2019 utilizing administrative databases held at the Institute of Clinical Evaluative Sciences (ICES). We assessed the incidence of surgically treated PUSD, demographics, initial surgical treatment and imaging modality, and risk factors for repeat intervention within 5 years. Statistical analyses summarized demographics, surgical trends, and logistic regression was used to identify risk factors for repeat surgical intervention.

RESULTS

We identified 1149 patients (mean age 11.3 years), with 59.6% older than 12 years. There was a decrease in the number of PUSD procedures performed per year that was close to statistical significance (p = 0.059) and a trend towards increased utilization of ureteroscopy (URS) compared with Shockwave Lithotripsy (SWL). In addition, there was a significant increase in the proportion of females surgically treated with PUSD (p = 0.001). In the 706 patients followed for 5 years, 17.7% underwent a repeat procedure within 6 months, while 20.4% underwent a repeat procedure from 6-months to 5 years. Renal stone location (OR 2.79, 95% confidence interval (CI) 1.62-4.80, p = 0.0002) and index SWL (OR 1.66, 95% CI 1.20-2.31, p = 0.0025) were risk factors for repeat surgical intervention within the first 6-months. There was an increasing utilization of ultrasound (US) compared to computerized tomography (CT) (p = 0.0008).

DISCUSSION

Despite the literature reporting increasing PUSD incidence, we observed a non-significant decrease in the number of surgical PUSD procedures performed. Exclusion of those treated conservatively may explain our results. The increase in the proportion of females treated reflects the narrowing gender gap in stone disease. A trend towards increased URS utilization was observed and re-intervention rates were similar to previous studies.

CONCLUSION

The overall rate of surgically treated PUSD did not show an increasing trend in Ontario, Canada from 2002 to 2019. URS was the most common surgical treatment modality, with a corresponding decline in SWL rates. PUSD was associated with a high surgical re-intervention rate within 6 months.

A comparative study of flexible ureteroscopic lithotripsy for upper urinary tract stones in patients with prior urosepsis following emergency drainage via retrograde ureteral stent or percutaneous nephrostomy

BACKGROUND

Patients with urosepsis associated with upper urinary tract stones require further stone management after emergency drainage.

OBJECTIVE

To evaluate the safety and efficacy of elective flexible ureteroscopic lithotripsy (F-URSL) for upper urinary tract stones in patients with prior urosepsis who have undergone emergency drainage using retrograde ureteral stent(RUS) or percutaneous nephrostomy (PCN).

METHOD

Between January 2017 and December 2021, clinical data were collected for 102 patients who underwent elective F-URSL following emergency drainage for urosepsis caused by upper ureteral or renal stones. The patients were categorized into two groups based on the drainage method used: the RUS group and the PCN group. The collected data included patient demographics, stone parameters, infection recovery after emergency drainage, and clinical outcomes post F-URSL. Subsequently, the data underwent statistical analysis.

RESULTS

A total of 102 patients were included in the statistical analysis, with 58 (56.86%) in the RUS group and 44 (43.14%) in the PCN group. Among the patients, 84 (82.35%) were female and 18 (17.65%) were male, with an average age of 59.36 years. Positive urine cultures were observed in 71 (69.61%) patients. Successful drainage was achieved in all patients in both groups, and there were no significant differences in the time required for normalization of white blood cell count (WBC) and body temperature following drainage. Additionally, all patients underwent F-URSL successfully, and no statistically significant differences were observed between the two groups in terms of operative time, stone-free rates, postoperative fever, and postoperative hospital stay.

CONCLUSION

Both RUS and PCN have been established as effective approaches for managing urosepsis caused by upper urinary tract stones. Furthermore, the impact of these two drainage methods on the subsequent management of stones through elective F-URSL has shown consistent outcomes.

Physical Techniques to Remove Residual Stone Fragments in the Urinary System

BACKGROUND

Although significant progress has been made in treatment techniques for renal and ureteral calculi, residual fragments (RF) persisting long after treatment pose a serious threat to patients' health. A variety of novel physical techniques and extraction devices are currently being developed to promote the removal of RF from the urinary system, and a series of in vivo experiments have demonstrated their safety and efficacy.

SUMMARY

External physical vibration lithecbole, magnetic extraction, biocompatible stone adhesive-based methods, and ultrasonic propulsion technologies are examples of innovative therapies that can promote the clearance of RF and improve the stone-free rate. In conclusion, the physical treatment of these RF needs to be optimized and improved. They are a promising technique for improving the efficiency of endovascular urology, and further in vivo studies are needed to confirm their safety and efficacy.

KEY MESSAGES

We have summarized the literature on removal of RF by physical methods in recent years, especially the new progress.

Bubble cloud characteristics and ablation efficiency in dual-frequency intrinsic threshold histotripsy

Histotripsy is a non-thermal focused ultrasound ablation method that destroys tissue through the generation and activity of acoustic cavitation bubble clouds. Intrinsic threshold histotripsy uses single-cycle pulses to generate bubble clouds when the dominant negative pressure phase exceeds an intrinsic threshold of ∼25-30 MPa. The ablation efficiency is dependent upon the size and density of bubbles within the bubble cloud. This work investigates the effects of dual-frequency pulsing schemes on the bubble cloud behavior and ablation efficiency in intrinsic threshold histotripsy. A modular 500 kHz:3 MHz histotripsy transducer treated agarose phantoms using dual-frequency histotripsy pulses with a 1:1 pressure ratio from 500 kHz and 3 MHz frequency elements and varying arrival times for the 3 MHz pulse relative to the arrival of the 500 kHz pulse (-100 ns, 0 ns, and +100 ns). High-speed optical imaging captured cavitation effects to characterize bubble cloud and individual bubble dynamics. The effects of dual-frequency pulsing on lesion formation and ablation efficiency were also investigated in red blood cell (RBC) phantoms. Results showed that the single bubble and bubble cloud size for dual-frequency cases were intermediate to published results for the component single-frequencies of 500 kHz and 3 MHz. Additionally, bubble cloud size and dynamics were shown to be altered by the arrival time of the 3 MHz pulse with respect to the 500 kHz pulse, with more uniform cloud expansion and collapse observed for early (-100 ns) arrival. Finally, RBC phantom experiments showed that dual-frequency exposures were capable of generating precise lesions with smaller areas and higher ablation efficiencies than previously published results for 500 kHz or 3 MHz. Overall, results demonstrate dual-frequency histotripsy's ability to modulate bubble cloud size and dynamics can be leveraged to produce precise lesions at higher ablation efficiencies than previously observed for single-frequency pulsing.

[Coronary lithotripsy in calcified lesions: fragmented calcium]

Background

Complex calcified coronary lesions are a frequent finding during percutaneous coronary intervention, representing for decades a challenge and limitation in patients with indication of revascularization, due to suboptimal angiographic results, high incidence of perioperative complications and long-term adverse events despite the multiple strategies employed, such as the use of cutting balloon, high-pressure balloons or rotational or orbital atherectomy, interventions with limitations that have hindered its routine use, recently a new plaque modification technique known as coronary intravascular lithotripsy has burst into the treatment of this complex entity, which consists in the use of a specially modified balloon for the emission of pulsatile mechanical energy (sonic pressure waves) that allows modifying the calcified plate.

Clinical case

By presenting a series of clinical cases and reviewing the literature, our initial experience is presented, key elements are summarized and discussed in the understanding of this new intervention technique necessary for decision making.

Conclusion

Coronary intravascular lithotripsy is projected as a promising technique for the modification and preparation of superficial and deep calcified coronary lesions, through microfractures that allow the apposition and effective expansion of the stent, strategy that according to different trials (Disrupt CAD series, SOLSTICE assay) and records presents a high efficiency and good safety profile, data consistent with our initial experience.

Comparing the efficacy of extracorporeal shock wave lithotripsy and ureteroscopic lithotripsy in the treatment of proximal ureteral stones in children: A retrospective study

OBJECTIVES

Ureteroscopic lithotripsy and extracorporeal shock wave lithotripsy methods are commonly used in the treatment of proximal ureteral stones. There are no adequate studies showing which method is more effective in children. In our study, we aimed to evaluate and compare the efficacy of two treatment methods, commonly used for proximal ureteral stones in children.

METHODS

A total of 78 patients who underwent ureteroscopic lithotripsy (n = 38) and extracorporeal shock wave lithotripsy (n = 40) due to stones located in the proximal ureter between 2010 and 2021 were included in the study. Demographic data, clinical characteristics, and treatment outcomes were retrospectively analyzed. Kolmogorov-Smirnov, Chi-square, and Mann-Whitney U tests were used for statistical analysis.

RESULTS

There was no statistical difference between the demographic characteristics of the groups, except for the mean age values (p = 0.008). A statistically significant difference was found in favor of the extracorporeal shock wave lithotripsy group in terms of stone-free rates after the first intervention, complication rates requiring intervention, re-intervention rates, and the average number of anesthesia sessions per patient until stone-free status (p = 0.043, p = 0.009, p = 0.017, and p < 0.001, respectively).

CONCLUSIONS

The results of this retrospective study suggest that extracorporeal shock wave lithotripsy is the primary treatment option for single, non-complicated proximal ureteral stones.

Vacuum-assisted dedusting lithotripsy in the treatment of kidney and proximal ureteral stones less than 3 cm in size

PURPOSE

This study aimed to compare the outcomes of vacuum-assisted dedusting lithotripsy (VADL) using flexible vacuum-assisted ureteral access sheath (FV-UAS) versus traditional flexible ureteroscopic lithotripsy (fURL) in patients with kidney or proximal ureteral calculi less than 3 cm in size.

METHODS

A total of 371 patients who successfully underwent fURL treatment were enrolled. These patients were divided into traditional fURL group and VADL group. Outcomes of both groups were compared using 1:1 propensity score-matched analysis. Stratified analyses based on stone size and location were also conducted.

RESULTS

Finally, 103 well-matched patients in each group were identified. No septic shock or death occurred. The immediate stone-free rate (SFR) and follow-up SFR of VADL group were significantly higher (78.6% vs. 50.5%, p < 0.001; 94.2%% vs. 75.7%, p < 0.001). No difference was observed in postoperative fever rate (2.9% vs. 3.9%, p = 1.000) and duration of lithotripsy (37.7 ± 20.1 min vs. 40.3 ± 18.9 min, p = 0.235). For patients with stones ≤ 2 cm in size, the immediate SFR and follow-up SFR in VADL group were higher (86.7% vs. 60.6%, p < 0.001; 96.0% vs. 83.1%, p = 0.010). The same trend was observed in the 2-3 cm subgroup (57.1% vs. 28.1%, p = 0.023; 89.3% vs. 59.4%, p = 0.009). Although the in situ fragmentation strategy was employed more frequently in VADL group for lower pole stones, the SFR was still higher. Subgroup analyses did not reveal any significant differences in either infectious complications or duration of lithotripsy.

CONCLUSION

VADL technique can significantly improve the postoperative SFR for the patients with kidney or proximal ureteral stones less than 3 cm in size treated by flexible ureteroscope.

A Comparison of Boron Supplement and Tamsulosin as Medical Expulsive Therapy for Urinary Stones After Extracorporeal Shock Wave Lithotripsy: a Randomized Controlled Clinical Trial

Treatment with alpha-blockers has been used in many studies to facilitate stone clearance after extra-corporeal shock wave lithotripsy (ESWL), based on mediating ureteral wall relaxation. Ureteral wall edema is another barrier against the stone passage. We aimed to compare the effectiveness of boron supplement (due to its anti-inflammatory effect) and tamsulosin in the passage of stone fragments after ESWL. Eligible patients after ESWL were randomly assigned to two groups and were treated with boron supplement (10 mg/BD) or tamsulosin (0.4 mg per night) for 2 weeks. The primary outcome was the stone expulsion rate according to the remained fragmented stone burden. The secondary outcomes were the time of stone clearance, pain intensity, drug side effects, and the need for auxiliary procedures. In this randomized control trial, 200 eligible patients were treated with boron supplement or tamsulosin. Finally, 89 and 81 patients in the two groups completed the study, respectively. The expulsion rate was 46.6% in the boron and 38.7% in the tamsulosin group, which there was no statistically significant difference between the two groups (p = 0.003), as well as the time of stone clearance (7.47 ± 22.4 vs 6.52 ± 18.45, days, p = 0.648, respectively), after 2-week follow-up. Moreover, pain intensity was the same in both groups. No Significant side effects were reported in the two groups. Boron supplement could be effective as adjuvant medical expulsive therapy after ESWL with no significant side effects in short-term follow-up. Iranian Clinical Trial Registration number and date of registration: IRCT20191026045244N3, 07/29/2020.

Erector spinae plane block prior to extracorporeal shock wave lithotripsy decreases fluoroscopy time and promise a comfortable procedure for renal stones: A prospective randomized study

INTRODUCTION AND OBJECTIVES

To compare the efficacy of erector spinae plane block (ESPB) and intramuscular (i.m.) diclofenac sodium in regard to pain management and impact on stone-free status in patients undergoing SWL.

PATIENTS AND MATERIALS

The study included patients who underwent SWL for kidney stones in our institution. The patients were randomly assigned to the ESPB (Group 1: n = 31) and i.m. 75 mg diclofenac sodium (Group 2: n = 30) groups. The demographic data of the patients, fluoroscopy time during SWL, number of need of targeting, total shocks given, voltage, stone free rates (SFR), analgesy method, number of SWL sessions, VAS score, stone location, maximum stone size, stone volume and Hounsfield unit (HU) were also recorded.

RESULTS

A total of 61 patients were included the study. There was no statistically significant difference between the two groups according to stone size, volume and density, SWL duration, total shocks given, voltage, BMI, stone-free status and stone location. Fluoroscopy time and number of need for stone targeting were significantly lower in group 1 than group 2 (p = 0.002, p = 0.021, respectively). The VAS score was significantly lower for group 1 compared to group 2 (p < 0.001).

CONCLUSIONS

We observed that the VAS score was lower in the ESPB group compared to i.m. diclofenac sodium group and although it was not statistically significant, we achieved a higher rate of stone-free status in the first session in ESPB group. Most importantly, the patients in the ESPB group were exposed to less fluoroscopy and radiation.

Application of tip-bendable ureteral access sheath in flexible ureteroscopic lithotripsy: an initial experience of 224 cases

INTRODUCTION

During the last decades, the advent of flexible ureteroscopic lithotripsy has revolutionized the management of upper urinary tract stones. We designed a patented tip-bendable ureteral access sheath to facilitate stone clearance. Our current study reported our initial experience of 224 cases.

MATERIALS AND METHODS

The study is a descriptive, retrospective analysis. The initial 224 cases, operated consecutively by one surgeon during 16 months, were reviewed. The novel tip-bendable ureteral access sheath was applied in the procedure. Demographics, laboratory tests, and peri- and postoperative findings (operation duration, stone-free rate (SFR), utilization of flexible instruments and complications) were analyzed.

RESUTLS

The median age of the patients was 56 years and the mean stones size was 2.3 ± 1.3 cm. There were 63 cases of upper ureteral stone, 93cases of renal stone and 68 cases of ureteral-renal stones. The mean operative time was 69.2 ± 65.2 min. The immediate stone-free rate was 76.8% and the 1 month post-operative stone-free rate was 97.3%. Most cases(95.5%)were success in single session. Two patient experienced post-operative fever. There was no unplanned readmission. The frequency of post-operative complications was estimated at 0.89% (Clavien I).

CONCLUSION

Flexible ureteroscopic lithotripsy with tip-bendable ureteral access sheath is a safe and effective procedure, which can achieve excellent stone clearance.

Comparison of efficacy and safety of flexible ureteroscopy and mini-percutaneous nephrolithotomy for 2-3 cm renal calculi in women: a single-center study

OBJECTIVE

This study aimed to compare the efficacy and safety of flexible ureteroscopic lithotripsy (FURSL) and mini-percutaneous nephrolithotomy (mPCNL) in the treatment of 2-3 cm renal calculi in women.

PATIENTS AND METHODS

Clinical data of 186 patients who underwent mPCNL (n=96) and FURSL (n=90) surgery in our hospital from June 2018 to February 2023 were collected. Several parameters were assessed and compared between the two groups, including operation duration, length of hospital stay, cost of hospitalization, pain intensity measured by the visual analogue scale (VAS), patient comfort assessed using the Bruggrmann Comfort Scale (BCS), decrease in hemoglobin levels, changes in blood urea nitrogen (BUN), fluctuations in serum creatinine (Scr), hypersensitive C-reactive protein (hs-CRP) levels, complication rates, immediate post-operative stone-free rate (RSFR), and long-term stone-free rate (LSFR).

RESULTS

The comparative analysis of patient age, body mass index (BMI), stone size, computed X-ray tomography (CT) value of stones, number of stones, and comorbidities revealed no statistically significant differences between the mPCNL and FURSL groups (p>0.05). The mPCNL cohort exhibited a markedly lower duration of operation (p<0.001) and BCS score (p<0.001) compared to the FURSL cohort. Nonetheless, the mPCNL cohort demonstrated significantly higher hospitalization expenses (p<0.001), length of hospital stay (p<0.001), VAS score for pain (p<0.001), and level of hemoglobin decrease (p<0.001) in comparison to the FURSL cohort. Moreover, the immediate post-operative stone-free rate (RSFR) was significantly higher in the mPCNL group (p=0.007). The long-term stone-free rate (LSFR), however, showed no significant difference between the two groups (p=0.160). Furthermore, the FURSL group exhibited significantly fewer overall complications in contrast to the mPCNL group (p=0.006).

CONCLUSIONS

mPCNL and FURSL are both safe and effective surgical methods for treating 2-3 cm renal calculi in women. However, FURSL holds distinct advantages, including minimally invasive procedure, accelerated recovery, reduced cost, and lower incidence of complications.

2022 Recommendations of the AFU Lithiasis Committee: Extracorporeal shock wave lithotripsy (ESWL)

Extracorporeal shock wave lithotripsy (ESWL) is a minimally invasive technique for the fragmentation of urinary tract stones using shock waves under fluoroscopic and/or ultrasound guidance. ESWL results depend on the indication (stone size/composition, clinical context) and also on how it is performed. The stone structure, nature and density (Hounsfield units; evaluated by CT without contrast agent) influence the fragmentation achieved by ESWL. The upper size limit of kidney stones has been lowered to 15mm (1.68cm3) due to the increased risk of steinstrasse with larger sizes and the potential need of anesthesia and ureteral stenting. Conversely, the development of endourological technologies allows a finer stone fragmentation and/or better elimination, thus reducing the risk of steinstrasse and decreasing the potential number of sessions or additional interventions. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations method (CPR) and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU 2022]) and their adaptability to the French context.

The use of intelligent analysis (IA) in determining the tactics of treating patients with nephrolithiasis

INTRODUCTION

The use of modern information technologies allows to increase confidence in the choice of a surgical treatment method of kidney stones, as well as to improve the quality of treatment due to an adequate combination of therapeutic techniques.

MATERIALS AND METHODS

In our study we analyzed the treatment results of 625 patients with kidney stones. We created a register with the information on more than 50 parameters for each patient. Each example had an output parameter representing a predefined treatment strategy (extracorporeal shock-wave lithotripsy [ESWL]-1, percutaneous nephrolithotomy [PCNL]-2, pyelolithotomy or nephrolithotomy-3). The initial database served as the basis for training the neural network estimation technique. The aim of our study was to assess the possibility of using neural network algorithms in choosing a method for surgical treatment of urolithiasis.

RESULTS

A prospective study was conducted to assess the clinical effectiveness of implementing the recommendations of the system. The average number of sessions in the group using the neural network assessment technique was 1.4. Residual fragments remained at the time of discharge in seven (15.6%) patients: four in the kidney, three in the lower third of the ureter "stone path." Inversion of therapeutic tactics-PCNL-was performed in four cases. The efficiency of the ESWL was 91.1%. The indicators of the ESWL in the comparison groups differed statistically significantly: in the second group, the efficiency was higher due to more stone fragmentation, with lower energy costs (the average number of sessions was 0.4 less).

CONCLUSION

The presented technique can be of help for a practicing urologist to choose the optimal treatment method for each patient, thereby minimizing the risk of early postoperative complications.