Flexible ureterorenoscopic management of upper tract pathologies

[Evaluation of stone size before flexible ureteroscopy: Which measurement is best?]

PURPOSE

To retrospectively assess the clinical utility in ureteroscopy (URS) planning of radiological parameters as predictor of stone-free status after a single flexible ureteroscopy.

MATERIAL

Sixty-seven patients with renal stones treated by flexible URS were retrospectively evaluated. To assess the clinical utility of radiological parameters, relationships between stone-free (SF) status and stone burden (maximal diameter, calculated area, calculated volume, cumulative diameter, and tridimentionnal volume [V3D]) were analyzed using the area under the receiver operating characteristics curve and logistic regression.

RESULTS

Maximal diameter (AUC=0.75), calculated area (AUC 0.79), calculated volume (AUC=0.79), cumulative diameter (AUC=0.80) and tridimensional volume (AUC=0.82) revealed ability to predict SF status after URS.

CONCLUSION

Stone burden evaluation is critical in predicting SF status after a single URS. Planar and volumetric measurements showed equal ability to predict SF status. V3D is more accurate but diameter measurement remains easier in clinical practice.

LEVEL OF EVIDENCE

4.

Flexible ureterorenoscopy results: Analysis of 279 cases

OBJECTIVE

In this study, the outcomes of 279 cases in whom we performed retrograde intrarenal surgery (RIRS) were evaluated retrospectively.

MATERIAL AND METHODS

RIRS was performed on 279 cases with the aid of access sheath of guidewire between March 2011 and February 2015. All patients were operated in the standard lithotomy position. A hydrophilic guidewire was inserted with the aid of rigid ureterorenoscopy and we checked whether there were any residual ureteral stones and other pathologies. Fluoroscopy was used routinely in all cases. Stone fragments smaller than 3 mm were left off but those bigger than 3 mm were removed by grasper after stone fragmentation. Controls of the patients were assessed by plain films (KUB), urinary tract ultrasonography (US) and/or computed tomography (CT) 1 month after the operation. Success rate of the procedure was defined as the stone-free status or presence of residual fragments less than 3 mm.

RESULTS

152 of the patients were male and 127 were female. The median ages of the male and female patients were 47.7 (1-86) ve 45.9 (3-79) years respectively. The median stone size was 13.5 mm (8-25). Preoperatively 34 (12.1%) patients had double-J ureteral stent. 19 (6.8%) patients were operated while they were still receiving antithrombotic and antiplatelet therapy Solitary kidney was present in 24 patients while the remaining patients had kyphoscoliosis (n=3), rotation anomaly (n=6), pelvic kidney (n=2), double collecting system (n=3), and horseshoe kidney (n=6). In 264 patients access sheath was used, in 15 patients operation was performed with the help of the guidewire. Double-J stents were inserted to 14 patients because of ureteral stricture and they underwent operation after 2 weeks later. Renal stones of 219 patients among all cases were fragmented completely and the patients were discharged as stone free (SF). Our success rate (SF or presence of clinically insignificant residual [CIRF]) was 78.4%. Stone size (p=0.029), stone number (p=0.01), stone location (p=0.023) had significant influence on the stone-free rate after RIRS The mean operation and floroscopy time was 62.5 min. (40-180) and 29.8 sec (4-96), respectively. The mean hospitalization time was 26.4 hours (12-72). Double J stents were placed to 253 patients for more stone burden and ureteral edema. Any complication was not observed for all cases except perioperative developed infection for two patients.

CONCLUSION

With advances in laser technology and flexible ureterorenoscopy, kidney stones can be treated with lower morbidity and high success rates.

Development and internal validation of a nomogram for predicting stone-free status after flexible ureteroscopy for renal stones

OBJECTIVE

To develop and internally validate a preoperative nomogram for predicting stone-free status (SF) after flexible ureteroscopy (fURS) for renal stones, as there is a need to predict the outcome of fURS for the treatment of renal stone disease.

PATIENTS AND METHODS

We retrospectively analysed 310 fURS procedures for renal stone removal performed between December 2009 and April 2013. Final outcome of fURS was determined by computed tomography 3 months after the last fURS session. Assessed preoperative factors included stone volume and number, age, sex, presence of hydronephrosis and lower pole calculi, and ureteric stent placement. Multivariate logistic regression analysis with backward selection was used to model the relationship between preoperative factors and SF after fURS. Bootstrapping was used to internally validate the nomogram.

RESULTS

Five independent predictors of SF after fURS were identified: stone volume (P < 0.001), presence of lower pole calculi (P = 0.001), operator with experience of >50 fURS (P = 0.026), stone number (P = 0.075), and presence of hydronephrosis (P = 0.047). We developed a nomogram to predict SF after fURS using these five preoperative characteristics. Total nomogram score (maximum 25) was derived from summing individual scores of each predictive variable; a high total score was predictive of successful fURS outcome, whereas a low total score was predictive of unsuccessful outcome. The area under the receiver operating characteristics for nomogram predictions was 0.87.

CONCLUSION

The nomogram can be used to reliably predict SF based on patient characteristics after fURS treatment of renal stone disease.