Operative Failure during Ureteroscopic Pneumatic Lithotripsy: Factors Affecting Successful Outcome

Does extracorporeal shock wave lithotripsy before retrograde intrarenal surgery complicates the surgery for upper ureter stone? The results of the RIRSearch group

AIMS

To evaluate the effect of pre-RIRS ESWL on the efficiency and safety of RIRS in the treatment of proximal ureter stones.

METHODS

The patients in the study population were divided into two groups. Group-1 was composed of patients who had undergone ESWL for proximal ureter stones before RIRS and Group-2 was composed of patients who directly underwent RIRS without any prior ESWL. The clinical and demographic properties of the patients were analysed in the RIRSearch database. The operative outcomes, peroperative complications, postoperative complications, hospitalisation time and stone-free rates were compared between the groups.

RESULTS

There were 56 patients in Group 1 and 95 patients in Group 2. The demographic and clinical properties were similar between the groups. The stone-free rates, peroperative complications and postoperative complications were also similar between the groups; however, the fluoroscopy time was significantly higher in Group 1 (P = .043). The cut-off duration of 10 weeks between ESWL and RIRS had reasonable/favourable discriminating ability, with a 51% sensitivity and 88% specificity rate for stone-free status.

CONCLUSION

Performing ESWL on the proximal ureter stones before RIRS did not change the efficacy and safety of RIRS. The time between the patient's last ESWL session and RIRS had a predictive value for stone-free status, but did not have any effect on complications.

Can stone migration be predicted preoperatively in ureteroscopic lithotripsy?

OBJECTIVE

In our study, we aimed to evaluate the parameters that are effective in predicting the possibility of stone migration during ureteroscopic lithotripsy.

PATIENTS AND METHOD

We divided our patients two group whom we applied ureteroscopic lithotripsy. Patients who migrated stones during ureteroscopic manipulation to the 1st group, and the patients who did not migrate stones to the second group were included. We measured the proximal ureter diameters of the patients in both groups on their computed tomography. We compared these values statistically. In addition, we determined a cut-off value for the ureter diameter to predict the possibility of stone migration.

RESULT

Especially, ureter diameters of patients with middle and lower ureter stones showed significant differences between groups. Also, stone sizes differed significantly between groups.

CONCLUSION

We concluded that the possibility of stone migration is high in patients with a ureter diameter higher than 7.45 mm in the middle and lower ureteric stones. Also, we believe that stone diameter and the surgeon's experience are effective factors in stone migration.

Effect of pulse energy, frequency and length on holmium:yttrium-aluminum-garnet laser fragmentation efficiency in non-floating artificial urinary calculi

BACKGROUND AND PURPOSE

Holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy is the standard lithotrite in ureteroscopy. We investigated the influence of pulse frequency, energy and length on the fragmentation efficiency of Ho:YAG laser lithotripsy in non-floating artificial stones in vitro.

MATERIALS AND METHODS

Stone fragmentation efficiency of three different Ho:YAG laser devices were evaluated in vitro at different pulse energy (1.0 and 2.0 J) and frequency settings (5 and 10 Hz), resulting in a standardized output power of 10W, respectively. Where possible, pulse length was modified (350 vs 700 microsec). Each setting was performed with a 273 microm and a 365 microm fiber. Lithotripsy was conducted using non-repulsive stones consisting of soft stone (plaster of Paris) and hard stone composition (Fujirock type 4).

RESULTS

Our results showed an increased stone disintegration efficiency at higher pulse energy (2.0 J/5 Hz vs 1.0 J/10 Hz) independently of two fiber diameters and stone types applied in this study (P < 0.05 in 18 of 20 groups). Similarly, reduction of the pulse length from 700 to 350 microsec resulted in a higher stone disintegration (P < 0.05 in 13 of 16 groups). This effect was most prominent when applied to soft stones. Higher fiber diameter was not constantly associated with an increase in stone disintegration.

CONCLUSION

We demonstrate that an increase of pulse energy and a reduction of pulse length at a standardized output power of 10W can improve Ho:YAG laser fragmentation efficiency in vitro in nonfloating stones. These results may potentially affect clinical practice of Ho:YAG laser lithotripsy in impacted or large stones, when retropulsion is excluded.

Factors affecting the outcome of ureteroscopy in the management of ureteral stones in children

PURPOSE

To identify the factors involved in failure and post-operative complications of retrograde rigid ureteroscopy (URS) in the treatment of ureteric stones in children.

METHODS

This is a retrospective study, including 33 children who underwent 34 rigid URS (one case bilateral) for obstructive ureteric stones over a period of 10 years. Patient age, sex, presenting symptoms, stone size and location, operative technique, surgical outcomes and complications were recorded. Ureteroscopy was done in a manner similar to that in adults. Statistical analysis was performed using the Mann-Whitney U, the Chi-square or Fisher's exact test.

RESULTS

There were 33 children (22 girls and 11 boys) with a mean age of 10.8 years (range 4-16 years) presenting 34 stones. The site of stones was pelvic in 24 cases (70.5%), iliac in 2 cases (6%) and lumbar in 8 cases (23.5%). The mean size of stones was 10.9 mm (5-22 mm). The success rate was 91%. There were no intraoperative complications. Post-operative complications rate was 21%. Factors associated with failure were size, localization of the stone, and delay of surgery. Factors associated with post-operative complications were size of the stone and operative time.

CONCLUSION

The rigid URS in children is a reliable and effective treatment option in the management of ureteric stones. Favorable factors for success of the procedure are pelvic stone and stone size <10 mm.