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 | |
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% |
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.