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New Dual Electromagnetic Shock Wave Lithotripter in the Management of Upper Urinary Tract Calculi under Analgesia

F. Anjum, J. Abbaraju, B. Varga, H. Marsh, S. Madaan, I. Dickinson, S. Sriprasad

Introduction:

*We report our preliminary results with this new Duet Magna Electromagnetic   Shockwave lithotripter in the management of upper urinary tract calculi.

*The lithotripter has two independent generator/reflector systems at 76◦ to each other.  It is used in synchronous mode.

*The dual shock waves produce a butterfly shaped focal volume which contributes to better fragmentation and probably lower kidney damage.

 

Material and Method:

*Data was collected prospectively 138 consecutive patients undergoing ESWL from June 2009 to September 2010 - performed under analgesia at 120 double shocks/min (120 shocks from each shock head).

*All patients were reviewed in the clinic at 4-6 weeks post ESWL with an X-Ray KUB

*Success was defined as completely stone free or with fragment < 3mm

 

Total number of patients studied

138

duetmagna_154 

Male: Female ratio

95-43

Mean Stone size

8.8 mm (range 5-20mm)

Mean shock wave time

30 minutes

 

Results:

Of the 138 patients: 108 had a single session, 25 had two sessions & 5 of them had 3 sessions.  The stone distribution included upper calyceal (16%), mid calyceal (10%), lower calyceal (57%), renal pelvic (15%) and proximal ureteric (1%).  Three patients (2%) did not tolerate the procedure well.  The stone free rate were 88% (5-10 mm), 73% (10-15mm) and 80% (15-20 mm).

 

Overall success rate is 83%  focus_350

 

 

Discussion/Conclusion:

*An animal model study using a Duet Lithotripter, showed a significant reduction in kidney damage.  "The lesion produced by 2400 SWs (1200 SWs/head, power level 10) at 120 SWs/min in alternating mode was quite low (0.22 ± 0.09% FRV)" and compares favorably with the lesion (1.08 ± 0.38%FRV) - "produced by 2400 SWs delivered with the HM3 lithotripter at 12 SWs/min (24 Kv)..." (Handa et al., 2009 J Urol).

*Dual shock wave electromagnetic lithotripsy is safe, quick and effective in treating upper urinary tract calculi. 

  • location: The Stone Center, Department of Urology, Darent Valley Hospital, Dartford, UK