Renal StoneNCT04071340
The Natural History of Minimally Symptomatic Nonobstructing Calyceal Stones
An observational study of Renal Stone, run by Assiut University at 1 site in Egypt.
Trial summary
The primary aim is to study the natural history of single-calyx asymptomatic nonobstructing stone disease. The Secondary aim is to determine the predictors of the need for intervention and of cure in such population. Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Renal Stone
- What is being tested?
- non-contrast MSCT, Abdominal ultrasonography and Urine analysis
- Type of treatment
- Medical device
- How many people
- 96 participants
- Where
- 1 siteEgypt
- Study dates
- 1 Sep 2019to 1 Jul 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 100 years
- All sexes
- Adult, Older adult
Study population: Patients attending the outpatient clinic of urolithiasis in Assiut Urology and Nephrology Hospital.
Who may be able to join
- Cases older than 18 years with renal stone disease affecting no more than one major calyx and causing neither obstruction nor bothersome pain.
- We define calyceal obstruction as calyceal dilatation with stone impaction at the calyceal neck.
- If the stones are not impacted or are casting the calyx, they are not considered obstructing.
Who cannot join
- Gross or microscopic hematuria.
- Patients who have difficulty to reach our tertiary center for follow-up.
- Other pathology in the target uretero-renal unit that requires intervention, e.g., ureteropelvic junction obstruction, malignancies, ureteric stones, …etc.
- History of recurrent urinary tract infection.
Trial locations and contacts
1 site in 1 country.
About this study
- The primary aim is to study the natural history of single-calyx asymptomatic nonobstructing stone disease.
- The Secondary aim is to determine the predictors of the need for intervention and of cure in such population.
Read the detailed description
The prevalence and incidence of urolithiasis have been increasing worldwide. The prevalence of urinary stone disease in the U.S. had increased from 5.5% at 1994 to 8.8% at 2010. In most of the European and Asian countries, the prevalence is high. The risk of developing urolithiasis in adults appears to be higher in the western hemisphere than in the eastern hemisphere, although the highest risks have been reported in some Asian countries such as Saudi Arabia (20.1%).
Although many lines of treatment have been developed for this disease, none of these lines is completely satisfactory and many cases are still not easy to manage. The lines of treatment for renal stones include:
- Open surgery: It includes nephrolithotomy and pyelolithotomy. Advances in endoscopic management of calculous disease promoted a rapid decrease in the use of this approach. The stone free rate (SFR) of open surgery is over 90%. Intraoperative complications, including bleeding requiring blood transfusion and pleural, vascular or ureteral injuries, represented about 37.8 %. Postoperative complications, including massive hematuria requiring blood transfusion, septicemia, urinary leakage and wound infection, were observed in 31.1%.
- Percutaneous nephrolithotripsy (PCNL): It offers direct removal of stone fragments through the nephrostomy tract. The SFR is up to 95%. Complications such as extravasation (7.2%), blood transfusion (11.2-17.5%) or post-operative fever (21-32.1%) are common. However, severe complications are rare, e.g., urosepsis (0.3-4.7%), perforation of the colon (0.2-0.8%) or pleura (0.0-3.1%).
- Retrograde intra-renal surgery (RIRS): With the advance in flexible ureteroscopic instrumentation and laser, the ability to access and treat intra-renal calculi has been improved [9]. SFR ranges between 90.9 and 93.3%. Intraoperative complications include mucosal injuries (1.5%), ureteral perforation (1.7%), significant bleeding (0.1%) and ureteral avulsion (0.1%). Post-operative complications include fever or urosepsis (1.1%), persistent hematuria (2%), renal colic (2.2%), transient vesico-ureteral reflux (4.6%), persistent vesico-ureteral reflux (0.1%) and ureteric stricture (0.1%).
- Extracorporeal shockwave lithotripsy (ESWL): Unlike more invasive urological modalities, ESWL does not remove stones as a whole; it disintegrates them into fragments of various sizes, and these fragments must pass out of the urinary tract spontaneously [11]. The SFR depends on stone location, size and composition [10]. It ranges from 45-98%. Complications include steinstrasse (4-7%), re-growth of residual stones (21-59%), renal colic (2-4%), sepsis (1-2.7%), symptomatic hematoma (<1%), asymptomatic hematoma (4%) and arrhythmia (11-59%).
- Pharmacological treatement.
- Active surveillance.
The financial burden on the U.S. health care system for urolithiasis alone costs more than $2 billion yearly. Naturally, the economic burden has a greater impact on developing countries.
The prevalence of urolithiasis in asymptomatic adults was 7.8% using low-dose non-contrast computed tomography according to a study in Wisconsin, U.S. The investigators could not find a study reporting the prevalence of asymptomatic nonobstructing calyceal stones although they encounter these cases frequently in the practice.
Single calyceal stones may present as a de novo finding, or they may be residual after PCNL, RIRS, ESWL or open surgery. Accordingly, many cases have scarring from previous surgery and/or have previous failed attempts at ESWL, so options of management are usually limited in these cases.
Research hypothesis: Substantial proportions of patients with asymptomatic nonobstructing calyceal stone(s) will not be complicated and does not require active treatment.
- Conditions
- Renal Stone
- Being tested
- non-contrast MSCT, Abdominal ultrasonography, Urine analysis, Urine culture
- Medical subject headings
- Nephrolithiasis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
non-contrast MSCTDevice
non-contrast multi-slice computed tomography
Abdominal ultrasonographyDevice
Abdominal ultrasonography
Urine analysisDiagnostic test
Urine analysis
Urine cultureDiagnostic test
Urine culture
What is being measured
The primary outcome is the main question the study is designed to answer.
study the natural history of single-calyx asymptomatic nonobstructing stone disease
Time to events indicating the need for intervention or cure
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Aug 2019
- Study start1 Sep 2019
- Primary completion1 Jun 2024
- Study completion1 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (11)Papers the sponsor has linked to this study.
- Other trials for Renal StoneStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 96 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Omar Anwar Sayed, Assiut University
- Investigators
- Ahmed S. Elazab, Professor, Study chair, Assiut UniversityMohamed E. Othman, Professor, Study chair, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04071340
- Sponsor's protocol ID
- Calyceal stones
- Status last verified
- Jul 2025
- First submitted
- 25 Aug 2019
- Last updated
- 23 Jul 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Shoag J, Tasian GE, Goldfarb DS, Eisner BH. The new epidemiology of nephrolithiasis. Adv Chronic Kidney Dis. 2015 Jul;22(4):273-8. doi: 10.1053/j.ackd.2015.04.004.
PubMed 26088071Lechevallier E, Traxer O, Saussine C. [Open surgery for upper urinary tract stones]. Prog Urol. 2008 Dec;18(12):952-4. doi: 10.1016/j.purol.2008.09.013. Epub 2008 Oct 16. French.
PubMed 19033059Lopez M, Hoppe B. History, epidemiology and regional diversities of urolithiasis. Pediatr Nephrol. 2010 Jan;25(1):49-59. doi: 10.1007/s00467-008-0960-5.
PubMed 21476230Matlaga BR, Assimos DG. Changing indications of open stone surgery. Urology. 2002 Apr;59(4):490-3; discussion 493-4. doi: 10.1016/s0090-4295(01)01670-3.
PubMed 11927296Alivizatos G, Skolarikos A. Is there still a role for open surgery in the management of renal stones? Curr Opin Urol. 2006 Mar;16(2):106-11. doi: 10.1097/01.mou.0000193379.08857.e7.
PubMed 16479213Desai M, Sun Y, Buchholz N, Fuller A, Matsuda T, Matlaga B, Miller N, Bolton D, Alomar M, Ganpule A. Treatment selection for urolithiasis: percutaneous nephrolithomy, ureteroscopy, shock wave lithotripsy, and active monitoring. World J Urol. 2017 Sep;35(9):1395-1399. doi: 10.1007/s00345-017-2030-8. Epub 2017 Mar 16.
PubMed 28303335Gross AJ, Knipper S, Netsch C. Managing caliceal stones. Indian J Urol. 2014 Jan;30(1):92-8. doi: 10.4103/0970-1591.124214.
PubMed 24497690Lai D, Chen M, He Y, Li X. Simultaneous retrograde intrarenal surgery for ipsilateral asymptomatic renal stones in patients with ureteroscopic symptomatic ureteral stone removal. BMC Urol. 2015 Mar 19;15:22. doi: 10.1186/s12894-015-0016-7.
PubMed 25888137Netsch C, Gross AJ. [Calyceal stones]. Urologe A. 2013 Aug;52(8):1135-45; quiz 1146-8. doi: 10.1007/s00120-013-3239-9. German.
PubMed 23860670Porfyris O, Delakas D. Post-extracorporeal shockwave lithotripsy residual stone fragments: clinical significance and management. Scand J Urol Nephrol. 2012 Jun;46(3):188-95. doi: 10.3109/00365599.2011.644861. Epub 2012 Feb 9.
PubMed 22321017Boyce CJ, Pickhardt PJ, Lawrence EM, Kim DH, Bruce RJ. Prevalence of urolithiasis in asymptomatic adults: objective determination using low dose noncontrast computerized tomography. J Urol. 2010 Mar;183(3):1017-21. doi: 10.1016/j.juro.2009.11.047. Epub 2010 Jan 21.
PubMed 20092842
Study at a glance
From the registry record, last updated by the sponsor on 23 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Natural History of Minimally Symptomatic Nonobstructing Calyceal Stones
- ClinicalTrials.gov ID
- NCT04071340
- Acronym / sponsor ID
- Calyceal stones
- Conditions
- Renal Stone
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 96 participants (actual)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- 1 Sep 2019 (actual)
- Primary completion
- 1 Jun 2024 (actual)
- Study completion
- 1 Jul 2025 (actual)
- First posted
- 28 Aug 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
- The primary aim is to study the natural history of single-calyx asymptomatic nonobstructing stone disease.
- The Secondary aim is to determine the predictors of the need for intervention and of cure in such population.
Detailed description
The prevalence and incidence of urolithiasis have been increasing worldwide. The prevalence of urinary stone disease in the U.S. had increased from 5.5% at 1994 to 8.8% at 2010. In most of the European and Asian countries, the prevalence is high. The risk of developing urolithiasis in adults appears to be higher in the western hemisphere than in the eastern hemisphere, although the highest risks have been reported in some Asian countries such as Saudi Arabia (20.1%).
Although many lines of treatment have been developed for this disease, none of these lines is completely satisfactory and many cases are still not easy to manage. The lines of treatment for renal stones include:
- Open surgery: It includes nephrolithotomy and pyelolithotomy. Advances in endoscopic management of calculous disease promoted a rapid decrease in the use of this approach. The stone free rate (SFR) of open surgery is over 90%. Intraoperative complications, including bleeding requiring blood transfusion and pleural, vascular or ureteral injuries, represented about 37.8 %. Postoperative complications, including massive hematuria requiring blood transfusion, septicemia, urinary leakage and wound infection, were observed in 31.1%.
- Percutaneous nephrolithotripsy (PCNL): It offers direct removal of stone fragments through the nephrostomy tract. The SFR is up to 95%. Complications such as extravasation (7.2%), blood transfusion (11.2-17.5%) or post-operative fever (21-32.1%) are common. However, severe complications are rare, e.g., urosepsis (0.3-4.7%), perforation of the colon (0.2-0.8%) or pleura (0.0-3.1%).
- Retrograde intra-renal surgery (RIRS): With the advance in flexible ureteroscopic instrumentation and laser, the ability to access and treat intra-renal calculi has been improved [9]. SFR ranges between 90.9 and 93.3%. Intraoperative complications include mucosal injuries (1.5%), ureteral perforation (1.7%), significant bleeding (0.1%) and ureteral avulsion (0.1%). Post-operative complications include fever or urosepsis (1.1%), persistent hematuria (2%), renal colic (2.2%), transient vesico-ureteral reflux (4.6%), persistent vesico-ureteral reflux (0.1%) and ureteric stricture (0.1%).
- Extracorporeal shockwave lithotripsy (ESWL): Unlike more invasive urological modalities, ESWL does not remove stones as a whole; it disintegrates them into fragments of various sizes, and these fragments must pass out of the urinary tract spontaneously [11]. The SFR depends on stone location, size and composition [10]. It ranges from 45-98%. Complications include steinstrasse (4-7%), re-growth of residual stones (21-59%), renal colic (2-4%), sepsis (1-2.7%), symptomatic hematoma (<1%), asymptomatic hematoma (4%) and arrhythmia (11-59%).
- Pharmacological treatement.
- Active surveillance.
The financial burden on the U.S. health care system for urolithiasis alone costs more than $2 billion yearly. Naturally, the economic burden has a greater impact on developing countries.
The prevalence of urolithiasis in asymptomatic adults was 7.8% using low-dose non-contrast computed tomography according to a study in Wisconsin, U.S. The investigators could not find a study reporting the prevalence of asymptomatic nonobstructing calyceal stones although they encounter these cases frequently in the practice.
Single calyceal stones may present as a de novo finding, or they may be residual after PCNL, RIRS, ESWL or open surgery. Accordingly, many cases have scarring from previous surgery and/or have previous failed attempts at ESWL, so options of management are usually limited in these cases.
Research hypothesis: Substantial proportions of patients with asymptomatic nonobstructing calyceal stone(s) will not be complicated and does not require active treatment.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Patients attending the outpatient clinic of urolithiasis in Assiut Urology and Nephrology Hospital.
Key inclusion criteria (3 listed)
- Cases older than 18 years with renal stone disease affecting no more than one major calyx and causing neither obstruction nor bothersome pain.
- We define calyceal obstruction as calyceal dilatation with stone impaction at the calyceal neck.
- If the stones are not impacted or are casting the calyx, they are not considered obstructing.
Key exclusion criteria (4 listed)
- Gross or microscopic hematuria.
- Patients who have difficulty to reach our tertiary center for follow-up.
- Other pathology in the target uretero-renal unit that requires intervention, e.g., ureteropelvic junction obstruction, malignancies, ureteric stones, …etc.
- History of recurrent urinary tract infection.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| non-contrast MSCTnon-contrast multi-slice computed tomography | Device | – |
| Abdominal ultrasonographyAbdominal ultrasonography | Device | – |
| Urine analysisUrine analysis | Diagnostic test | – |
| Urine cultureUrine culture | Diagnostic test | – |
Primary outcome
study the natural history of single-calyx asymptomatic nonobstructing stone disease
Time frame: Baseline
Time to events indicating the need for intervention or cure
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jul 2025.
- Background: PubMed 26088071Shoag J, Tasian GE, Goldfarb DS, Eisner BH. The new epidemiology of nephrolithiasis. Adv Chronic Kidney Dis. 2015 Jul;22(4):273-8. doi: 10.1053/j.ackd.2015.04.004.
- Background: PubMed 19033059Lechevallier E, Traxer O, Saussine C. [Open surgery for upper urinary tract stones]. Prog Urol. 2008 Dec;18(12):952-4. doi: 10.1016/j.purol.2008.09.013. Epub 2008 Oct 16. French.
- Background: PubMed 21476230Lopez M, Hoppe B. History, epidemiology and regional diversities of urolithiasis. Pediatr Nephrol. 2010 Jan;25(1):49-59. doi: 10.1007/s00467-008-0960-5.
- Background: PubMed 11927296Matlaga BR, Assimos DG. Changing indications of open stone surgery. Urology. 2002 Apr;59(4):490-3; discussion 493-4. doi: 10.1016/s0090-4295(01)01670-3.
- Background: PubMed 16479213Alivizatos G, Skolarikos A. Is there still a role for open surgery in the management of renal stones? Curr Opin Urol. 2006 Mar;16(2):106-11. doi: 10.1097/01.mou.0000193379.08857.e7.
- Background: PubMed 28303335Desai M, Sun Y, Buchholz N, Fuller A, Matsuda T, Matlaga B, Miller N, Bolton D, Alomar M, Ganpule A. Treatment selection for urolithiasis: percutaneous nephrolithomy, ureteroscopy, shock wave lithotripsy, and active monitoring. World J Urol. 2017 Sep;35(9):1395-1399. doi: 10.1007/s00345-017-2030-8. Epub 2017 Mar 16.
- Background: PubMed 24497690Gross AJ, Knipper S, Netsch C. Managing caliceal stones. Indian J Urol. 2014 Jan;30(1):92-8. doi: 10.4103/0970-1591.124214.
- Background: PubMed 25888137Lai D, Chen M, He Y, Li X. Simultaneous retrograde intrarenal surgery for ipsilateral asymptomatic renal stones in patients with ureteroscopic symptomatic ureteral stone removal. BMC Urol. 2015 Mar 19;15:22. doi: 10.1186/s12894-015-0016-7.
- Background: PubMed 23860670Netsch C, Gross AJ. [Calyceal stones]. Urologe A. 2013 Aug;52(8):1135-45; quiz 1146-8. doi: 10.1007/s00120-013-3239-9. German.
- Background: PubMed 22321017Porfyris O, Delakas D. Post-extracorporeal shockwave lithotripsy residual stone fragments: clinical significance and management. Scand J Urol Nephrol. 2012 Jun;46(3):188-95. doi: 10.3109/00365599.2011.644861. Epub 2012 Feb 9.
- Background: PubMed 20092842Boyce CJ, Pickhardt PJ, Lawrence EM, Kim DH, Bruce RJ. Prevalence of urolithiasis in asymptomatic adults: objective determination using low dose noncontrast computerized tomography. J Urol. 2010 Mar;183(3):1017-21. doi: 10.1016/j.juro.2009.11.047. Epub 2010 Jan 21.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ahmed S. Elazab, Professor study chair
Assiut University
Mohamed E. Othman, Professor study chair
Assiut University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Renal Stone, run by Assiut University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
study the natural history of single-calyx asymptomatic nonobstructing stone disease (time frame: Baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04071340, which also lists 11 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Jul 2025.