Elsevier

Urology

Volume 78, Issue 4, October 2011, Pages 733-737
Urology

Endourology and Stones
Does Pelvicaliceal System Anatomy Affect Success of Percutaneous Nephrolithotomy?

https://doi.org/10.1016/j.urology.2011.03.058Get rights and content

Objective

To investigate the effect of the pelvicaliceal system (PCS) anatomy on the percutaneous nephrolithotomy (PCNL) success rate. Although the caliceal anatomy is effective for stone clearance after shock wave lithotripsy and retrograde intrarenal lithotripsy, the effect of the caliceal anatomy after PCNL has not been evaluated to date.

Methods

A total of 498 patients who had undergone PCNL and preoperative intravenous urography were enrolled in our study. Kidney-related anatomic factors, such as the PCS surface area and type, degree of hydronephrosis, infundibulopelvic angle, upper-lower calix angle, infundibular length, and infundibular width were calculated using intravenous urography. The association between the PCNL success rate and kidney-related anatomic factors was retrospectively analyzed using chi-square tests, Fisher's exact test, Mann-Whitney U test, and forward stepwise regression analysis.

Results

A success rate of 78.1% was achieved. No difference was seen the success rates among the PCS types. The mean PCS surface area was 20.1 ± 9.7 cm2 in patients with successful outcomes and 24.5 ± 10.2 cm2 in patients with remaining stones (P = .001). The mean infundibulopelvic angle, upper-lower calix angle, infundibular length, and infundibular width were similar in both groups. Multivariate binary logistic regression analysis showed that stone configuration and PCS surface area were independent factors affecting the PCNL success rates.

Conclusion

The results of our study have shown that the PCS surface area is the only anatomic factor that affects the PCNL success rate and patients with a PCS surface area <20.5 cm2 have greater PCNL success.

Section snippets

Material and Methods

A total of 1012 PCNL procedures were performed in the Department of Urology at our department from January 2006 to February 2010. Of these, 573 procedures with preoperative intravenous urography (IVU) were retrospectively analyzed. Patients with radiolucent stones and/or low-quality IVU results were excluded, because these factors can confuse the measurement of other anatomic factors. The remaining 498 procedures were included in our study.

The PCS anatomic factors we analyzed included the PCS

Results

A success rate of 78.1% was achieved (group 1), and 21.9% patients had residual stones (group 2). Both groups were similar with respect to age, sex distribution, and body mass index. No significant difference was found with respect to a history of open surgery between the 2 groups (18.3% in group 1 vs 22.0% in group 2, P = .23). The mean stone size was 7.1 ± 4.8 cm2 for group 1 and 9.2 ± 6.2 cm2 for group 2 (P = .001). Group 1 contained 82 patients (21.1%) with staghorn stones, and group 2

Comment

The PCNL success rate has progressively increased since the technique was first used in 1976 because of the many advances in endoscopic equipment and techniques. The PCNL success rate varies from 72% to 98%, with acceptable complication rates reported for large series.11, 12, 13

The PCS anatomy is one of the most neglected aspects during endourologic stone removal. Because a thorough understanding of PCS anatomy is necessary to perform reliable endourologic procedures, several different PCS

Conclusions

PCNL is an effective treatment modality for all types of PCS. Of the anatomic variables we examined, the PCS surface area appeared to be the only anatomic factor that affected the PCNL success rate, and patients with a <20.5 cm2 PCS surface area had greater PCNL success rates. Therefore, surgeons should be aware that patients with a large PCS (for any reason, including previous surgery or stone obstruction) might have lower PCNL success rates, and these patients should be informed accordingly.

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