Abstract Objective. Extracorporeal shockwave lithotripsy (ESWL) is the management of choice for ureteric and renal stones 20 mm or smaller, with a stone clearance rate of up to 89%. This study determined whether such a high success rate could apply to centres using mobile ESWL, by reviewing the performance at one centre that provides such a service. Material and methods. Between July 2011 and July 2012, 222 patients (median age 51 years, range 18-90 years) underwent one to five sessions of ESWL for ureteric and renal stones (mean size 15 mm, range 4-22 mm). Stone clearance was regarded as residual fragments 2 mm or smaller after completion of sessions. Results. In total, 110 out of 222 patients (49%) were clear of stones. Stones were radiopaque in 198 (89%) and radiolucent in 24 patients (11%), with clearance rates of 48% and 63%, respectively. Regarding size, 36 (16%) were 1-5 mm, 144 (65%) 5-10 mm, 28 (12%) 10-15 mm, eight (4%) 15-20 mm and six (3%) larger than 20 mm, with clearance rates of 61%, 55%, 18%, 13% and 50%, respectively. In total, 173 (78%) were renal stones and 49 (22%) ureteric, with respective clearance rates of 49% and 51%. For kidney stones, 15 (9%) were in the upper, 32 (18%) in the mid, 75 (43%) in the lower pole and 51 (30%) in the pelvis, with clearance rates of 52%, 59%, 49% and 41%; for ureteric stones, 32 (65%) were in the upper, 10 (20%) in the mid and seven (15%) in the lower ureter, with clearance rates of 47%, 70% and 43%, respectively. Conclusion. The performance of mobile ESWL was significantly poorer than expected, and this may be related to a lack of clinical ownership. The authors believe that such a service should be permanently placed on site.

1. Mr. Shady Nafie
Urology Clinical Research Fellow
Dr. Jonathan Mills
FY1 in Urology
Dr. Jaitender Minhas
FY1 in Urology
Mr. Masood A Khan
Urology Consultant
Mobile Lithotripsy Service
The Efficacy of
A one-year review of 222 patients
Mr. James E Dyer
Urology Clinical Research Fellow

2. • Introduced in February 1980
• Approved by FDA in 1984
• Dramatically changed the management
of urinary tract stones
Extra-corporeal Shock Wave Lithotripsy
ESWL

3. EAU Guidelines
ESWL can remove > 90% of stones in adults
Stone Size ≤20 mm >20 mm
Stone
Clearance
Rates
66-99% 45-63%
Stone
Clearance
Rates
(Dornier HM3 Lithotripter)
75-89% 39-63%

4. Success rate depends on:
Lithotripter
Patient Operator
Stone
• Efficacy
• Size
• Site
• Density
• Habitus (BMI) • Efficiency

5. LGH Performance
• Storz MODULITH® SLK Lithotripter.
• Dual localisation (Ultrasound, X-ray
mobile image intensifier).
• Technicians.
• Middle grade doctor.
July 2011 - July 2012

6. LGH Performance
• Site.
• Size.
• Opacity.
• Density.
• Number.
• Shocks.
• Energy.
Stones Sessions Stents
• Yes/No
• ≤2 mm residual stone, was considered stone clear.
• Statistical analysis: Fisher’s exact test.

7. LGH Performance
• 222 cases.
• Mean Age: 51 yrs. (18-90).
• Male : Female = 2.4 :1

8. LGH Performance
Mean values:
• Size: 15 mm (4-24)
• Density: 811 HU (181-1711).
• Shocks: 3185 (1550 - 4000).
• Energy: 17.3 KV (9.8 - 20).

9. LGH Performance
Number of ESWL sessions

10. LGH Performance
Total Stone Clearance* Rate
*≤2 mm residual stone, was considered stone clear.

11. LGH Performance
Stone Clearance Yes No P-Value
Number of
Patients
110 112 N/A
Mean HU 747 854 <0.05
Mean Shocks 3252 3155 <0.05
Mean Energy 17 17 0.732

12. LGH Performance
Stone Size
61% 55% 18% 13% 50%
P < 0.01

13. LGH Performance
P = 0.577
Site Number Cleared Percentage
Upper Pole 15 8 53%
Middle Pole 32 19 59%
Lower Pole 75 37 49%
Kidney Pelvis 51 21 41%
Upper Ureter 32 15 47%
Middle Ureter 10 7 70%
Lower Ureter 7 4 57%
Stone Site

14. LGH Performance
46%
Stent vs No Stent (Ureteric stones)
52% P = 0.394

15. LGH Performance
49%
Stone Opacity
52% P = 0.829

16. LGH Performance
55% 33% P < 0.01
Stone Density (HU)

17. LGH Performance
53%
Sex
42% P = 0.141

18. Conclusion
The performance of our mobile ESWL service is
significantly poorer than that expected.
49.5% 66-99%vs.

19. Factors affected Stone Clearance
Rate
Lithotripter
Patient Operator
Stone
?? Efficacy
✔ Size
✔ Density
X Opacity
X Site.
X Stent
X Sex
?? Habitus (BMI)
✔ No. of shockwaves
?? Energy level
?? Efficiency

20. Conclusion
Maintenance?
Technician?
Lack of Ownership?
Mobile ESWL

21. Questions
Dr. Jonathan Mills
FY1 in Urology
Dr. Jaitender Minhas
FY1 in Urology
Mr. Masood A Khan
Urology Consultant
Mr. Shady Nafie
Urology Research Fellow
Mr. James E Dyer
Urology Research Fellow