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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


*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



Male: Female ratio


Mean Stone size

8.8 mm (range 5-20mm)

Mean shock wave time

30 minutes



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




*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

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