BJU Int. 2011 Apr 21. doi:10.1111/j.1464-410X.2011.10495.x

Trends in urological stone disease

Benjamin W. Turney, John M. Reynard, Jeremy G. Noble and Stephen R. Keoghane*

Oxford Stone Group, Department of Urology, Nuffi eld Department of Surgical Sciences, The Churchill Hospital, Oxford, and *Department of Urology, Queen Alexandra Hospital, Portsmouth, UK

Abstract

OBJECTIVE:
To summarize the changes in prevalence and treatment of upper urinary tract stone disease in the UK over the last 10 years.

METHODS:
Data from the Hospital Episode Statistics (HES) website (http://www.hesonline.nhs.uk) were extracted, summarized and presented.

RESULTS:
- The number of upper urinary tract stone hospital episodes increased by 63% to 83050 in the 10-year period.
- The use of shock wave lithotripsy (SWL) for treating all upper tract stones increased from 14491 cases in 2000 – 2001 to 22402 cases in 2010 (a 55% increase) with a 69% increase in lithotripsy for renal stones.
- There was a 127% increase in the number of ureteroscopic stone treatments from 6   283 to 14   242 cases over the 10-year period with a 49% increase from 2007/2008 to 2009/2010.
- There was a decline in open surgery for upper tract stones from 278 cases in 2000/2001 to 47 cases in 2009/2010 (an 83% reduction).
- Treatment for stone disease has increased substantially in comparison with other urological activity. In 2009/2010, SWL was performed almost as frequently as transurethral resection of the prostate or transurethral resection of bladder tumour, ureteroscopy for stones was performed more frequently than nephrectomy, radical
prostatectomy and cystectomy combined, and percutaneous nephrolithotomy was performed more frequently than
cystectomy.

CONCLUSIONS:
- The present study highlights the increase in prevalence and treatment of stone disease in the UK over the last 10 years.
- If this trend continues it has important implications for workforce planning, training, service delivery and research in the fi eld of urolithiasis.


JOURNAL OF ENDOUROLOGY JOURNAL OF ENDOUROLOGY Volume 23, Number 9, September 2009 (C) Mary Ann Liebert, Inc. Pp. 1395–1398 DOI: 10.1089=end.2009.0391olume 23, Number 9, September 2009 (C) Mary Ann Liebert, Inc. Pp. 1395–1398 DOI: 10.1089=end.2009.0391

Retrograde Ureteroscopy for Renal Stones Larger Than 2.5 cm

Julie M. Riley, M.D., Laura Stearman, M.D., and Scott Troxel, M.D.

Department of Urology, University of Missouri, Columbia, Missouri.

Abstract

Introduction and Objectives:
Because of the advances in endoscopic technology, retrograde flexible ureteroscopy (URS) is being applied to larger renal stone burdens. For stones greater than 2.5 cm, percutaneous nephrolithotomy has long been considered the standard of care. We have encountered a growing population of patients who desire a less invasive, less disruptive approach to large renal stones. We present our experience with retrograde ureteroscopic management of renal stones larger than 2.5 cm.

Methods:
Twenty-two patients between October 2004 and June 2008 underwent retrograde flexible URS with holmium laser lithotripsy. Each patient underwent retrograde URS using the Storz Flex-X and a ureteral access sheath.  Patients  were  evaluated  for  number of  procedures,  stone  clearance  rates,  and hospital admissions. Postoperative kidney, ureter, and bladder radiograph was used to determine stone-free rates.

Results:
Mean stone size was 3.0 cm. The average number of procedures was 1.82 with 5 patients requiring one,
14 requiring two, and 1 requiring three procedures. There were two failures who went on to have percutaneous
nephrolithotomy, both of whom had significant lower pole stone burden. Overall stone-free rate was 90.9%.
There were three overnight admissions for stent pain, and one 3-day admission for bacteremia in a patient who
was noncompliant with preoperative antibiotics.

Conclusions:
Planned staged URS is a viable option for the treatment of renal stones larger than 2.5 cm with
excellent stone-free results. Significant lower pole stone burden is a limiting factor.


J Urol. 2011 Oct;186(4 Suppl):1728-33. Epub 2011 Aug 19.

Use of the ureteral access sheath during ureteroscopy in children.

Wang HH, Huang L, Routh JC, Kokorowski P, Cilento BG Jr, Nelson CP.

Department of Urology, Children’s Hospital Boston, Boston, Massachusetts.

Abstract

PURPOSE:
The use of ureteral access sheaths during ureteroscopy is common but there are sparse data on the safety and outcomes of ureteral access sheath use in children. We compared the outcomes of ureteroscopy with vs without a ureteral access sheath in children.

MATERIALS AND METHODS:
We retrospectively reviewed all ureteroscopy procedures for urolithiasis in patients younger than 21 years at our hospital from 1999 to 2009. The primary outcome was intraoperative complications. Secondary outcomes were postoperative hydronephrosis, emergency room visit/hospital readmission within 90 days, stone-free status and need for re-treatment. We analyzed associations of a ureteral access sheath with outcomes.

RESULTS:
A total of 34 boys and 62 girls with a mean age of 13 years underwent ureteroscopy. A ureteral access sheath was used in 40 of the 96 patients (42%). The mean stone burden was 9.6 mm. Median followup was 11 months (range 0.2 to 110). Intraoperative complication occurred in 7 cases, including perforation/extravasation in 4, a submucosal wire in 2 and stent migration in 1. Intraoperative complications were more common when a sheath was used (15% vs 2%, adjusted OR 8.2, 95% CI 1.3-50.9, p = 0.02). Postoperative hydronephrosis was observed in 7 of 73 cases (10%) but it was not significantly more common when a sheath was used. No ureteral stricture was identified. Sheath use was not associated with postoperative telephone calls, emergency room visits or rehospitalization. Although the stone-free rate tended to be higher in cases without a sheath (78% vs 59%, p = 0.09), this association was not significant in a multivariate model (p = 0.6).

CONCLUSIONS:
Although intraoperative complications occur more commonly during ureteroscopy with a ureteral access sheath, no increase in longer term adverse effects were observed. Future prospective studies of ureteral access sheath use in children with longer followup are warranted.

Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.


Urol Res. 2011 Oct;39(5):357-60. Epub 2010 Dec 30.

Clinical significance of uric acid dihydrate in urinary stones.

Strohmaier WL, Seilnacht J, Schubert G.

Department of Urology and Paediatric Urology, regioMed Kliniken, Klinikum Coburg, Ketschendorfer Str. 33, 96450, Coburg, Germany, walter.strohmaier@klinikum-coburg.de.

Abstract

Uric acid crystallizes as an anhydrous compound (UAA), a dihydrate (UAD) or a mixture of both. A monohydrate form is very rare. About 20% of uric acid stones contain a significant amount (≥20%) UAD. It is believed that UAD crystallizes under highly acidic conditions (urine pH ≤ 5.0). Up to now, metabolic data on patients with UAD stones have not been reported in the literature. One hundred and fifty patients with pure uric acid calculi were studied. Stone analysis was performed using X-ray diffraction. According to the stone analysis, they were divided in two groups: 1. UAD (≥20% UAD), 2. UAA (<20% UAD). In all patients the following parameters were examined: age, sex, number of recurrences, body mass index (BMI); blood: creatinine, uric acid, calcium, sodium, and potassium; urine: pH-profiles, volume, calcium, uric acid, citrate, ammonia, and urea. Group 1 (≥20% UAD) consisted of33patientsand group 2 (<20% UAD) of 117 patients. Between these groups, there was a significant difference concerning the number of recurrences, the urine volume, and the urinary excretion of calcium. Patients with ≥20% dihydrate had a mean BMI of 31.6 ± 7.5, a mean number of recurrences of 0.24 ± 0.44, an urine volume of 2.6 ± 0.8 l/24 h, and a calcium excretion of 4.5 ± 2.2 mmol/24 h, whereas those with <20% dihydrate had BMI of 29.9 ± 5.0, 1.10 ± 1.42 recurrences, urine volume of 2.3 ± 1.2 l/24 h, and calcium excretion of 3.2 ± 2.4 mmol/24 h. All the other parameters tested were not significantly different. For the first time, our study shows metabolic data in uric acid patients with a significant amount of UAD. The comparison between this group and those patients with <20% UAD revealed that the first group is less prone to develop recurrences. This is a relevant difference concerning the necessity of metaphylactic measures. We could not confirm in patients with dihydrate if the urinary pH is more acid than in those with insignificant amounts of dihydrate. The higher 24-h urine volume, the higher excretion of calcium, and the higher BMI in the UAD group may be of pathophysiological relevance and requires further attention.


Urol Res. 2011 Sep 10.

Distension of the renal pelvis in kidney stone patients: sensory and biomechanical responses.

Pedersen KV, Liao D, Osther SS, Drewes AM, Gregersen H, Osther PJ.

Urological Research Center, Department of Urology, Fredericia Hospital, Part of Hospital Littlebelt, University of Southern Denmark, Dronningensgade 97, 7000, Fredericia, Denmark.

Abstract

The pathogenesis of symptoms in urolithiasis is poorly understood. Traditionally increased endoluminal pressure is considered the main mechanism causing pain in the upper urinary tract but clinical data are sparse. The aim of the present study was to develop a new model related to mechanosensation in order to describe the geometric and mechanical properties of the renal pelvis in patients with kidney stone disease. Pressure measurement in the renal pelvis was done during CT-pyelography in 15 patients who underwent percutaneus nephrolithotomy. The sensory intensity was recorded at the thresholds for first sensation and for pain. 3D deformation and strain were calculated in five patients. The deformation of pelvis during distension was not uniform due to the complex geometry. The pelvis deformed to 113 ± 6% and 115 ± 11% in the longitudinal and circumferential directions, respectively. Endoluminal pressure in the renal pelvis corresponded positively to the sensory ratings but the referred pain area was diffuse located and varied in size. The present study provides a method for describing the mechanosensory properties and 3D deformation of the complex renal pelvis geometry. Although there was a relation between pressure and pain score, the non-homogenous spatial strain distribution suggests that the 3D biomechanical properties of the renal pelvis are not reflected by simple estimates of tension based on pressure and volume.


Urology. 2011 Sep 20.

Effective Radiation Exposure in Evaluation and Follow-up of Patients With Urolithiasis.

Fahmy NM, Elkoushy MA, Andonian S.

Division of Urology, Department of Surgery, McGill University Health Centre, McGill University, Montreal, Quebec, Canada.

Abstract

OBJECTIVE:
To quantify the effective radiation dose associated with the evaluation and follow-up of patients with urolithiasis.

METHODS:
Retrospective review was performed for consecutive patients presenting to a tertiary stone clinic with acute stone episodes between November 2007 and December 2008, and had at least 2 years of follow-up. Number and modality of imaging studies were collected. Effective radiation exposure (ERE) doses were calculated from the dose length product values reported with each computed tomography (CT) scan.

RESULTS:
There were 72 males and 32 females with a mean age of 49 years (range 21-78). Patients underwent an average 1.8 (range 0-5) and 0.7 (range 0-2) plain radiographs, 0.82 (range 0-4) and 0.15 (range 0-2) CTs, 0.09 (range 0-1) and 0.03 (range 0-1) intravenous urograms, and 0.3 (range 0-1) and 0.6 (range 0-2) ultrasounds (US) during the first and second years, respectively (all P <.05). The average calculated ERE dose per CT scan was 23.16 mSv (range 4.94-72.77). The calculated mean ERE dose per patient significantly decreased from 29.29 mSv (range 1.7-77.27) in the first year to 8.04 mSv (range 1.4-24.72) in the second year (P <.01). This was because of significantly fewer CT scans and significantly more US imaging during the second year (P <.05). Although 18 (17.3%) patients exceeded 50 mSv during the first year, none exceeded this threshold during the second year. The mean ERE dose did not correlate with stone location, patient age, and sex.

CONCLUSION:
The calculated mean ERE dose significantly decreased during the second year of follow-up in patients with urolithiasis because of significantly higher use of US.

Copyright © 2011 Elsevier Inc. All rights reserved.


Eur Urol. 2011 Sep 28.

Incidence, Prevention, and Management of Complications Following Percutaneous Nephrolitholapaxy.

Seitz C, Desai M, Häcker A, Hakenberg OW, Liatsikos E, Nagele U, Tolley D.

Department of Urology, St. John of God Hospital, Teaching Hospital of the Medical University of Vienna, Austria.

Abstract

CONTEXT:
Incidence, prevention, and management of complications of percutaneous nephrolitholapaxy (PNL) still lack consensus.

OBJECTIVE:
To review the epidemiology of complications and their prevention and management.

EVIDENCE ACQUISITION:
A literature review was performed using the PubMed database between 2001 and May 1, 2011, restricted to human species, adults, and the English language. The Medline search used a strategy including medical subject headings (MeSH) and free-text protocols with the keywords percutaneous, nephrolithotomy, PCNL, PNL, urolithiasis, complications, and Clavien, and the MeSH terms nephrostomy, percutaneous/adverse effects, and intraoperative complications or postoperative complications.

EVIDENCE SYNTHESIS:
Assessing the epidemiology of complications is difficult because definitions of complications and their management still lack consensus. For a reproducible quality assessment, data should be obtained in a standardized manner, allowing for comparison. An approach is the validated Dindo-modified Clavien system, which was originally reported by seven studies. No deviation from the normal postoperative course (Clavien 0) was observed in 76.7% of PNL procedures. Including deviations from the normal postoperative course without the need for pharmacologic treatment or interventions (Clavien 1) would add up to 88.1%. Clavien 2 complications including blood transfusion and parenteral nutrition occurred in 7%; Clavien 3 complications requiring intervention in 4.1.%; Clavien 4, life-threatening complications, in 0.6%; and Clavien 5, mortality, in 0.04%. High-quality data on complication management of rare but potentially debilitating complications are scarce and consist mainly of case reports.

CONCLUSIONS:
Complications after PNL can be kept to a minimum in experienced hands with the development of new techniques and improved technology. A modified procedure-specific Clavien classification should be established that would need to be validated in prospective trials.

Copyright © 2011. Published by Elsevier B.V.


Urol Res. 2011 Sep 8.

Is shock wave lithotripsy efficient for the elderly stone formers? Results of a matched-pair analysis.

Philippou P, Lamrani D, Moraitis K, Bach C, Masood J, Buchholz N.

Endourology and Stone Services, Department of Urology, Barts and The London NHS Trust, Smithfield, London, EC1A 7BE, UK.

Abstract

The aim of the study was to evaluate the impact of age on the efficacy of extracorporeal shock wave lithotripsy (SWL), in a comparative study based on the principles of matched-pair analysis. Over a period of 4 years, 2,311 patients were treated with SWL in a tertiary referral center. Patient and stone data were recorded in a prospective electronic database. Among these patients, 115 (4.97%) were older than 70 years of age and fulfilled the criteria for inclusion in the study (Group A). For the purposes of the comparative analysis, Group A patients were matched for gender and stone parameters (side, location of stone, and diameter ±2 mm) with a control group of patients under the age of 70 (Group B). Following matching, the patients’ electronic medical records were reviewed, to identify SWL success rates at 3 months and McNemar’s test was used to compare the efficacy of SWL between the two groups. Matching was possible in all cases. The results indicate that there were no statistically significant differences in the mean number of SWL sessions or in the mean number of impulses per session between the two groups. The overall stone clearance rate achieved by SWL alone was 71.3% for Group A and 73.9% for group B. Discordant pairs were found in 37 cases (in 17 pairs only patients in Group A became stone-free, while in 20 pairs only patients in Group B became stone-free). By using McNemar’s test, the difference in stone clearance rates between the two groups was not found to be statistically significant (p = 0.742). A total of 22 patients (19.1%) in Group A and 17 patients (14.7%) in Group B underwent an adjuvant procedure to achieve stone clearance. McNemar’s test also revealed the absence of any statistically significant difference in SWL success rates between older and younger patients in the subgroups of patients presenting with either ureteric or renal stones (p = 0.727 and p = 0.571, respectively). In conclusion, SWL is still considered one of the first-line tools for geriatric patients suffering from urolithiasis, as increased age alone does not seem to adversely affect the efficacy of SWL.


Kidney Int. 2011 Sep 28. doi: 10.1038/ki.2011.336.

Nephrocalcinosis and urolithiasis in children.

Habbig S, Beck BB, Hoppe B.

Division of Pediatric Nephrology, Department of Pediatrics, University of Cologne, Cologne, Germany.

Abstract

The incidence of adult urolithiasis has increased significantly in industrialized countries over the past decades. Sound incidence rates are not available for children, nor are they known for nephrocalcinosis, which can appear as a single entity or together with urolithiasis. In contrast to the adult kidney stone patient, where environmental factors are the main cause, genetic and/or metabolic disorders are the main reason for childhood nephrocalcinosis and urolithiasis. While hypercalciuria is considered to be the most frequent risk factor, several other metabolic disorders such as hypocitraturia or hyperoxaluria, as well as a variety of renal tubular diseases, e.g., Dent’s disease or renal tubular acidosis, have to be ruled out by urine and/or blood analysis. Associated symptoms such as growth retardation, intestinal absorption, or bone demineralization should be evaluated for diagnostic and therapeutic purposes. Preterm infants are a special risk population with a high incidence of nephrocalcinosis arising from immature kidney, medication, and hypocitraturia. In children, concise evaluation will reveal an underlying pathomechanism in >75% of patients. Early treatment reducing urinary saturation of the soluble by increasing fluid intake and by providing crystallization inhibitors, as well as disease-specific medication, are mandatory to prevent recurrent kidney stones and/or progressive nephrocalcinosis, and consequently deterioration of renal function.

Kidney International advance online publication, 28 September 2011; doi:10.1038/ki.2011.336.


Pediatr Nephrol. 2011 Aug 4.

Urinary calcium and uric acid excretion in children with vesicoureteral reflux.

Madani A, Kermani N, Ataei N, Esfahani ST, Hajizadeh N, Khazaeipour Z, Rafiei S.

Department of Pediatric Nephrology, Children’s Hospital Medical Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

Abstract

Urolithiasis is relatively common in children, and identifiable predisposing factors for stone formation, including metabolic and structural derangements, can be established in most cases. Vesicoureteral reflux (VUR) is a common cause of kidney stone formation. The pathophysiological mechanism of urolithiasis in reflux is related to urinary tract infection and urinary stasis, both of which promote urinary crystal formation, but metabolic causes, such as crystallurias (mostly hypercalciuria), may also be involved in this process. However, few studies on urinary calcium and uric acid excretion in children with VUR have been conducted. We have studied the frequency of hypercalciuria and hyperuricosuria in children with VUR and compared the results with those from a control group. The VUR group comprised 108 children with VUR (19 boys, 89 girls; age range 3 months to 12 years), and the control group comprised 110 healthy children without any history of reflux or urinary tract infection (30 boys, 80 girls; age range 2 months to 12 years). Fasting urine was analyzed for the calcium/creatinine (Ca/Cr) and uric acid/creatinine (UA/Cr) ratios. Hypercalciuria was more frequently diagnosed in the VUR patients than in the control group (21.3 vs. 3.6%; P = 0.0001). Significant differences between the two groups were also found for the mean Ca/Cr and UA/Cr ratios (P = 0.0001 and P = 0.0001, respectively). No differences were found in the urinary Ca/Cr or UA/Cr ratios related to VUR grading or unilateral/bilateral VUR in the patient group, with the exception of those for hypercalciuria and mild VUR (P = 0.03). The association of urinary stones and microlithiasis in the VUR group was 29.6%. Our results demonstrate that the frequency of hypercalciuria and hyperuricosuria was higher in pediatric patients with VUR than in healthy children. Knowing this relationship, preventive and therapeutic interventions for stone formation in VUR could be greatly expanded.


J Urol. 2011 Oct;186(4 Suppl):1728-33. Epub 2011 Aug 19.

Use of the ureteral access sheath during ureteroscopy in children.

Wang HH, Huang L, Routh JC, Kokorowski P, Cilento BG Jr, Nelson CP.

Department of Urology, Children’s Hospital Boston, Boston, Massachusetts.

Abstract

PURPOSE:
The use of ureteral access sheaths during ureteroscopy is common but there are sparse data on the safety and outcomes of ureteral access sheath use in children. We compared the outcomes of ureteroscopy with vs without a ureteral access sheath in children.

MATERIALS AND METHODS:
We retrospectively reviewed all ureteroscopy procedures for urolithiasis in patients younger than 21 years at our hospital from 1999 to 2009. The primary outcome was intraoperative complications. Secondary outcomes were postoperative hydronephrosis, emergency room visit/hospital readmission within 90 days, stone-free status and need for re-treatment. We analyzed associations of a ureteral access sheath with outcomes.

RESULTS:
A total of 34 boys and 62 girls with a mean age of 13 years underwent ureteroscopy. A ureteral access sheath was used in 40 of the 96 patients (42%). The mean stone burden was 9.6 mm. Median followup was 11 months (range 0.2 to 110). Intraoperative complication occurred in 7 cases, including perforation/extravasation in 4, a submucosal wire in 2 and stent migration in 1. Intraoperative complications were more common when a sheath was used (15% vs 2%, adjusted OR 8.2, 95% CI 1.3-50.9, p = 0.02). Postoperative hydronephrosis was observed in 7 of 73 cases (10%) but it was not significantly more common when a sheath was used. No ureteral stricture was identified. Sheath use was not associated with postoperative telephone calls, emergency room visits or rehospitalization. Although the stone-free rate tended to be higher in cases without a sheath (78% vs 59%, p = 0.09), this association was not significant in a multivariate model (p = 0.6).

CONCLUSIONS:
Although intraoperative complications occur more commonly during ureteroscopy with a ureteral access sheath, no increase in longer term adverse effects were observed. Future prospective studies of ureteral access sheath use in children with longer followup are warranted.

Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.


CORSI DI AGGIORNAMENTO E CONGRESSI:

31st congress of the societè internazionale d’urologie
16-20 ottobre 2011
Berlino

84th congress nazionale della società italiana di urologia
23-26 ottobre 2011
Roma

XXI congresso nazionale AIUG
6-8 novembre 2011
Torino

Congresso nazionale SUN
10-12 novembre 2011
Roma

Technology and training in endourology
10-12 novembre 2011
Torino