Stepwise shock wave lithotripsy: Results of initial study for the treatment of urinary stones in childhood

Effect of output voltage distribution on stone comminution efficiency during shockwave lithotripsy in renal or ureteropelvic junction stones: a preliminary study

OBJECTIVE

This study evaluated stone comminution efficiency according to the distribution of the lithotripter output voltage during extracorporeal shockwave lithotripsy (SWL) of renal or ureteropelvic junction (UPJ) stones.

MATERIAL AND METHODS

Sixty-two patients with a single radiopaque renal or UPJ stone of surface area about 50-400 mm(2) were prospectively randomized to receive a total of 2400 shocks per session according to one of three shock protocols: group A, output voltage was increased from 25% to 35% to 45% with 800 shocks per voltage; group B, constant output voltage of 35%; group C, decreasing output voltage from 45% to 35% to 25%. SWLs were carried out using a fourth generation electroconductive lithotripter, the Sonolith Vision, without anesthesia. The stone-free (SF) and success (SF + clinically insignificant residual fragment) rates were assessed.

RESULTS

Patient demographics, body mass index, stone burden, laterality and stone locations were comparable among the three groups. There were no differences in the cumulative success rates (30%, 32% and 35% after the first session for groups A, B and C, respectively; 65%, 50% and 65% after the second session; and 80%, 68% and 75% after the third session). The cumulative SF rates and complications showed no differences among the three groups.

CONCLUSIONS

In this preliminary study, manipulation of the lithotripter output voltage distribution did not affect stone comminution efficiency for renal or UPJ stones. This finding should be confirmed by larger studies including more patients.

Shock wave lithotripsy: a randomized, double-blind trial to compare immediate versus delayed voltage escalation

OBJECTIVES

To present a randomized trial investigating immediate vs delayed voltage escalation during shock wave lithotripsy (SWL). SWL efficiency is affected by the energy setting of the lithotripter, the consumption level of the electrode, and the rate of shock wave administration. Preliminary data have suggested that delaying voltage escalation for SWL might both improve fragmentation and minimize renal injury.

METHODS

A total of 160 patients with previously untreated radiopaque renal calculi were randomized to undergo immediate vs delayed voltage escalation SWL. Success was defined as an asymptomatic patient who was stone free or had adequate fragmentation (sand or fragments < or = 4 mm) at 3 months after treatment.

RESULTS

Of the 160 patients, 83 were treated with immediate voltage escalation SWL and 77 patients with delayed escalation. The groups were similar in sex, body mass index, stone area, and stone location. The overall success rate at 3 months was 72.5% for immediate vs 54.5% for delayed SWL (P = .021). After adjusting for body mass index, sex, and stone location, the stone area decreased more rapidly in patients treated with immediate voltage escalation (P = .002). A trend was also seen for immediate voltage escalation to be more effective in the treatment of smaller calculi with a cross-sectional area of < 100 mm(2) (P = .089) compared with calculi with a cross-sectional area of > or = 100 mm(2) (P = .248). No differences were seen in the complications or ancillary procedures between the 2 treatments (P = .667 and P = .355, respectively). No perinephric hematomas were observed in either group.

CONCLUSIONS

These results suggest that delayed voltage escalation might not provide superior stone fragmentation compared with conventional, immediate voltage escalation.

Pediatric urolithiasis: an 8-year experience of single centre

OBJECTIVE

The objective was to investigate the clinical features and metabolic and anatomic risk factors for kidney stone formation in our patient group.

METHODS

Between 1998 and 2005, 179 children (94 girls, 85 boys) followed in our department because of urolithiasis were enrolled to participate in our study. Clinical presentation, urinary tract infection, stone localisation, positive family history, stone composition, presence of anatomic abnormalities and urinary metabolic risk factors, and treatment modality were evaluated retrospectively.

RESULTS

The mean age at diagnosis of stone disease was 4.5 years (range 0.25-15.3 years). The mean follow-up duration was 8 months (range 1-98). The major clinical presentations of our patients were abdominal pain and/or flank pain in 100 children (55.9%) and macroscopic hematuria in 25 (14%). Urinary tract infection was detected in 20% of patients on admission. Forty-three children (24%) had a urinary tract abnormality and ureteropelvic junction obstruction was the most common abnormality. A family history of stone disease was recorded in 98 patients (54.7%). Stones were located within the renal parenchyma in 90 patients. Hypercalciuria and hyperuricosuria were detected in 42.3 and 54.8% respectively. Stone analysis was performed in 63 children and calcium oxalate was a major mineral. Surgical treatment was performed in 49 children and extracorporeal shock wave lithotripsy (ESWL) in 41 children.

CONCLUSION

We think that urolithiasis remains a serious problem in children in our country. Family history of urolithiasis, urologic abnormalities (especially under the age of 5 years), metabolic disorders and urinary tract infections tend to indicate childhood urolithiasis.