The Durability of Active Surveillance in Patients with Asymptomatic Kidney Stones: A Systematic Review

Is traditional stone clinic the optimal use of NHS resources?

There is no clear guidance on the efficacy of stone follow-up. NICE have been unable to make recommendations with current published evidence. The aim of this study was to understand the patient journey resulting in surgical intervention, and whether traditional stone follow-up is effective. A retrospective review of patients undergoing ureteroscopy (URS) or percutaneous nephrolithotomy (PCNL) over a 3 year period identified 471 patients who underwent these procedures to treat stone disease. Records were interrogated for the following: symptoms, mechanism of booking, reason for intervention, stone size, stone location, risk factors and previous follow-up. Of 471 patients who underwent intervention, 168 were booked from stone clinic follow-up (36%). Of these, 96% were symptomatic and 4% were asymptomatic. When risk factors were removed, this figure was reduced to 1%. Sepsis rate for emergency admissions differs between those followed up (13%) versus new presentations (19)%. There was no statistically significant difference in the outpatient imaging frequency between patients booked from an emergency admission (80% having imaging every 6 months) and those from the clinic (82%). Our Hospital provides on average 650 stone clinic appointments a year with a cost of £93,000. Given the low rate of intervention in patients with asymptomatic renal stones, a symptomatic, direct-access emergency stone clinic could be a better model of care and use of NHS resources. Urgent research is required in this area to further assess if this is the case.

2022 Recommendations of the AFU Lithiasis Committee: Summary of indications

The spontaneous elimination rate of ureteral stones decreases with their size, but also in function of their location. The objectives of stone surveillance are to detect the occurrence of a complication (e.g., fever, clinical tolerance) and to verify the potential stone migration/elimination. The use of urological procedures and the choice of technique are based on many different factors. Kidney stone surveillance is proposed mainly to people with low risk of progression or complications (size<4mm and/or lower calyx location and non-infection stone). Surveillance may be extended to patients with larger stones, in function of the clinical context and comorbidities. Conversely, a urological procedure may also be proposed to patients with stones<4mm for professional (e.g., soldier, pilot, expatriate) or social reasons or if travelling is planned. The choice of technique is based on the stone composition (if already known) and density, the advantages and limitations of each technique, and also the clinical context, while trying to choose the least invasive procedure for a stone-free objective. 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. This chapter is based on the references used in the chapters on the different techniques (extracorporeal shock wave therapy, ureteroscopy, percutaneous nephrolithotomy, medical expulsive therapy, postural therapy, chemolysis by alkalinization) as well as the American Urological Association (AUA) and EAU recommendations.

Urologists are optimistic surgeons: prevalence and predictors of discordance between intraoperative stone-free rate and cross-sectional imaging evaluation after vacuum-assisted mini-percutaneous nephrolithotomy

Purpose

To assess how accurate are urologists in predicting stone-free status (SFS) after vacuum-assisted mini-PCNL (vamPCNL) compared to computed tomography (CT) and clinical predictors of discordant SFS.

Methods

Data from 235 patients who underwent vamPCNL were analysed. Patient’s demographics, stones’ characteristics and operative data were recorded. SFS was evaluated intraoperatively by the treating urologist (iSFS) and with non-contrast CT 3 months after vamPCNL (ctSFS). SFS was defined as no residual stones. Stone complexity was scored with the Guy’s score. Descriptive statistics and logistic regression models were used to identify clinical factors associated with discordant SFS (namely iSFS not confirmed at CT).

Results

iSFS and ctSFS were 88.5% and 65.5%, respectively, with 54 (23%) cases resulting in discordant evaluation of SFS between the surgeon and CT imaging. Patients with discordant SFS had larger stone volume (p < 0.001), higher rate of multiple stones (p = 0.03) and higher rate of multiple calyceal groups affected by stones (p < 0.001) than those with concordant SFS. The use of flexible ureteroscopes to look for residual stones after lithotripsy was more frequently reported in cases with concordant SFS (p = 0.001). Multivariable logistic regression analysis revealed that stones in > 2 calyceal groups (OR 10.2, p < 0.001), Guy’s score II (OR 5.8, p < 0.01) and not using flexible ureteroscopes after lithotripsy (OR 2.9, p = 0.02) were independent predictors of discordant SFS.

Conclusion

One out of five patients is erroneously considered SF after vamPCNL. Urologist should carefully evaluate patients with multiple calyceal stones and consider using flexible ureteroscopes to complete lapaxy of migrated fragments in order to improve their prediction of SFS.

Should we treat asymptomatic concurrent contralateral renal stones? A longitudinal analysis

The objective is to explore the need for future surgery among patients treated for asymptomatic concurrent contralateral stones versus those that were not. Upon IRB approval, we retrospectively reviewed records of patients who underwent stone surgeries (SWL, URS, PCNL) from 2009 to 2018. Patients were included if they were greater than 18 years old, had a minimum follow-up of 2 years, and had pre-operative imaging. Patients were divided into three groups: bilateral surgery, ipsilateral surgery with, and without asymptomatic concurrent contralateral stones. Cox regression was used to analyze patients' need for future surgery while controlling demographic and comorbid characteristics. Of the 1666 patients included, 51.9% were men. They were 59.7 ± 15 years and had a BMI of 31.3 ± 8.2 kg/m². During the follow-up of 5.2 ± 2.2 years (range 2-11 years), patients who had bilateral surgery and patients who had ipsilateral surgery without treatment of the asymptomatic concurrent contralateral stones had no difference in the need for future surgery (41.7% vs. 43%, p = 0.585). When stratified by stone size, patients with contralateral stones > 6 mm were more likely to require future surgical treatment than those treated bilaterally (p < 0.001). Our study demonstrates that treating asymptomatic concurrent contralateral stones does not lower the need for future surgical interventions. However, asymptomatic concurrent contralateral stones > 6 mm may portend earlier need for treatment. Therefore, bilateral treatment should be considered at presentation.

The best treatment approach for lower calyceal stones ≤ 20 mm in maximal diameter: mini percutaneous nephrolithotripsy, retrograde intrarenal surgery or shock wave lithotripsy. A systematic review and meta-analysis of the literature conducted by the European Section of Uro-Technology and Young Academic Urologists

INTRODUCTION

The highest in quality data in the literature which compared mini percutaneous nephrolithotripsy (mPCNL), retrograde intrarenal surgery (RIRS) and shock wave lithotripsy (SWL) for the management of lower pole stone (LPS) with a maximal diameter ≤20mm were investigated by means of systematic review (SR) and meta-analysis.

EVIDENCE ACQUISITION

A SR of the literature was conducted on PubMed®, Cochrane, SCOPUS® and EMBASE® in January 2020. The study complied with the PRISMA statement and recommendations of the EAU Guidelines office. Only randomized controlled trials (RCTs) comparing retrograde intrarenal surgery (RIRS), shock wave lithotripsy (SWL) and mini-percutaneous nephrolithotripsy (mPCNL) were selected for the meta-analysis. The endpoints were the efficacy of each modality, measured by stone-free rate (SFR), operative time and retreatment rate and the safety of each method, based on hospitalization time and complications. Subgroup analyses for stones with a maximal diameter <10mm and 10-20 mm were performed.

EVIDENCE SYNTHESIS

Twenty-one RCTs were included in the meta-analysis. mPCNL had the highest SFR and the lowest retreatment rate among the three modalities, while SWL had the lowest SFR and the highest retreatment rate. The operative and hospitalization time were shorter in the case of SWL, whereas they were similar in the case of mPCNL and RIRS. The highest complication rate was observed in mPCNL group, which accounted for 8.3-22.4%, while RIRS and SWL had similar complication rates, which ranged between 1.3-31.4% and 0-48.5%, respectively. Further classification of the complications according to Clavien-Dindo system revealed that SWL had lower grade II complication rates compared to mPCNL and RIRS. Regarding stones <10mm, SWL and RIRS had similar SFR, complication rate, operation and hospitalization time. SWL had higher retreatment rate.

CONCLUSIONS

For LPSs ≤20mm, mPCNL provides the highest SFR and the lowest retreatment rate. This modality has a higher complication rate and longer hospital stay in comparison to the other modalities. SWL provides the lowest SFR with the highest retreatment rate. RIRS has similar complication rate to SWL and could be preferred over SWL. For stones up to 10mm, SWL may provide a valid alternative. Despite a higher retreatment rate, its SFR is similar to RIRS.

Natural history of small asymptomatic kidney and residual stones over a long-term follow-up: systematic review over 25 years

OBJECTIVE

To systematically review the natural history of small asymptomatic kidney and residual stones, as the incidental identification of small, asymptomatic renal calculi has risen with increasing use of high-resolution imaging.

MATERIALS AND METHODS

We reviewed the natural history of small asymptomatic kidney and residual stones using the Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. We searched MEDLINE, Scopus, EMBASE, EBSCO, Cochrane library and Clinicaltrials.gov using themes of 'asymptomatic', 'nephrolithiasis', 'observation', 'symptoms', 'admission', 'intervention' and similar allied terms for all English language articles from 1996 to 2020 (25 years). Inclusion criteria were studies with ≥50 patients, stones ≤10 mm, and a mean follow-up of ≥24 months. Primary outcomes were occurrence of symptoms, emergency admission, and interventions.

RESULTS

Our literature search returned 2247 results of which 10 papers were included in the final review. Risk of symptomatic episodes ranged from 0% to 59.4%. Meta-analysis did not identify any significant difference in the likelihood of developing symptoms when comparing stones <5 mm to those >5 mm, nor those <10 mm to those >10 mm. Risk of admission varied from 14% to 19% and the risk of intervention from 12% to 35%. Meta-analysis showed a significantly decreased likelihood of intervention for stones <5 vs >5 mm and <10 vs >10 mm. Studies had variable risk of bias due to heterogeneous reporting of outcome measures with significant likelihood that observed differences in results were compatible with chance alone (Symptoms: I² =0%, Cochran's Q = 3.09, P = 0.69; Intervention: I² =0%, Cochran's Q = 1.76, P = 0.88).

CONCLUSIONS

The present systematic review indicates that stone size is not a reliable predictor of symptoms; however, risk of intervention is greater for stones >5mm vs <5 mm and >10 vs <10 mm. This review will inform urologists as they discuss management strategies with patients who have asymptomatic renal stones and offer insight to committees during the development of evidence-based guidelines.

Decreased Recurrence of Urolithiasis After Simultaneous Ureteroscopic Surgery for Ureter and Ipsilateral Renal Calculi: Comparison to Shockwave Lithotripsy for Ureter Calculi Alone

OBJECTIVE

To compare follow-up outcomes of ureteroscopy (URS) and shockwave lithotripsy (SWL) for ureter calculi in the setting of asymptomatic renal calculi <15 mm.

METHODS

This study included 789 patients who underwent URS (n = 301) or SWL (n = 488) as primary treatment for ureter calculi and who had ipsilateral renal calculi <15 mm between January 2012 and December 2019. For the URS group, all renal calculi were simultaneously treated unless contraindicated. One-to-one matching was performed using the propensity score (PS).

RESULTS

After PS matching, analysis included 262 matched pairs of URS and SWL patients. The stone-free rate for ureter calculi without auxiliary procedure was 97.3% in the URS group and 93.9% in the SWL group. Any complication rates were 11.0% and 9.2% in the URS and SWL group, respectively; 1.1% of the URS patients experienced complications classified as Clavien-Dindo ≥IIIb. The estimated 2-year intervention-free survival was 88.1% in the URS group and 84.2% in the SWL group (P = 0.045). The estimated 2-year stone-event-free survival was 80.1% in the URS group and 71.0% in the SWL group (P = 0.009). Cox multivariate analysis showed that the hazard ratios of URS were 0.62 (P = 0.025) for surgical interventions and 0.64 (P = 0.008) for stone-related events after adjusting for baseline variables.

CONCLUSION

For patients with symptomatic ureter calculi and asymptomatic renal calculi <15 mm, URS with active treatment for renal calculi reduces future ipsilateral surgical intervention and stone-related events compared with SWL for ureter calculi.

Lessons Learnt (Clinical Outcomes and Cost Savings) from Virtual Stone Clinic and Their Application in the Era Post-COVID-19: Prospective Outcomes over a 6-Year Period from a University Teaching Hospital

Introduction: We introduced a nurse-led telephone-based virtual stone clinic (VSC) follow-up for the surveillance of patients with asymptomatic renal calculi or those at a high risk of recurrent kidney stone disease (KSD). The aim of this study was to look at the outcomes of VSC and its role in the post-COVID era. Methods: Prospective outcomes audit was done for all patients referred to the VSC for a 6-year period (March 2014-April 2020). VSC is led by specialist stone nurses for on-going surveillance of KSD patients. Results: A total of 290 patients were seen (468 individual appointments; 1.6 ± 1.0 per patient), with a mean age of 57.0 ± 15.8 years (range: 17-92) and a men-women ratio of 3:2. The referral was for surveillance of asymptomatic small renal stones (230, 79.3%); history of recurrent stone disease (45, 15.5%); solitary kidneys (5, 1.7%); cystine stones; young age; and other conditions (10, 3.4%). The mean stone size was 5.0 ± 2.7 mm, followed up with kidney, ureter, and bladder radiograph (225, 77.6%) and ultrasound scan (USS) (65, 22.4%), for median duration of 12 months (range: 3-24 months). At the end, 132 patients (45.6%) remained in VSC, 106 (36.6%) were discharged, 47 (16.2%) returned to face-to-face clinic or treatment, and 5 (1.7%) had emergency admissions. Of 47 patients who returned, 23 (48.9%) developed new symptoms, 21 (44.6%) had stone growth, and 3 defaulted to face-to-face appointment. Thirty-five patients needed surgical intervention (URS-21, SWL-13, and PCNL-1) and 10 were managed conservatively. VSC reduced the cost per clinic appointment from £27.9 to £2 per patient (93% reduction), equating to a total saving of £12,006 for the study period. Conclusion: Nurse-led VSC not only provided a safe follow-up but also allowed to substantially reduce the cost of treatment by allowing patients to be either discharged or return to a face-to-face clinic or surgical intervention if needed. Post-COVID, this model using telemedicine will have a much wider uptake and further help to optimize health care resources.

Treatment of isolated small renal stones leads to resolution of symptoms and should be routinely offered to patients: retrospective outcomes from a university hospital

INTRODUCTION

Treatment of smaller renal stones and the symptomatic value it offers to patients is often debated. We wanted to analyse surgical outcomes for treatment of small renal stones and whether treatment resulted in symptom resolution.

MATERIALS AND METHODS

All patients who underwent ureterorenoscopy (URS) for isolated symptomatic small renal stones ≤10 mm over a 7-year period were retrospectively included and subdivided into those with stones of ≤7 mm (Group A) and stones of 8-10 mm (Group B). Patients with multiple renal stones, ureteric stones, or combined renal and ureteric stones were excluded. Based on the symptoms, the patient groups were those with pain, urinary tract infection (UTI) and haematuria. Resolution of symptoms was defined as no symptoms during the follow-up period.

RESULTS

A total of 109 patients with a single small renal stone ≤10 mm underwent URS and stone treatment, with mean age of 50 years and a male:female ratio of 1:1.2. The mean operative time was significantly longer in Group B (55.9 min vs 33.07 min, p = 0.001). In total, 97.2% (n = 70) of patients in Group A and 83.7% (n = 31) of patients in Group B were stone free (p = 0.017). Complete resolution of symptoms was seen in 63 (92.6%), 24 (85.7%) and 13 (100%) patients with pain, UTI and haematuria, respectively. There were no statistically significant differences in symptom resolution between patients with stones ≤7 mm and those with stones 8-10 mm in size.

CONCLUSION

Ureteroscopic treatment is a feasible option for small symptomatic stones, since it may lead to symptom resolution. Based on our study we would recommend that patients with symptomatic small renal stones are offered endoscopic treatment.