Management of Solitary Renal Pelvic Stone: Laparoscopic Retroperitoneal Pyelolithotomy Versus Percutaneous Nephrolithotomy

Introduction

S ince the introduction of shockwave lithotripsy (SWL) in 1980 for the management of renal stones, the concept of minimally invasive therapy in the management of urolithiasis has developed and various new techniques have been introduced. ¹ Previously, surgical management was the only available option for urinary stones; currently, there are many minimally invasive modalities to select from, such as percutaneous nephrolithotomy (PCNL) and ureteroscopy. Moreover, the introduction of different methods of stone fragmentation has improved the rate of stone clearance among the same modalities. ² As regards renal stones, PCNL is the treatment of choice in most cases. ³

Laparoscopic renal surgery has become focused since the initial report of laparoscopic nephrectomy by Clayman and colleagues, ⁴ and the concept of stone removal by laparoscopy has become more developed, especially after the description of retroperitoneal balloon dilation and retroperitoneoscopy by Gaur and associates. ⁵ The indications for laparoscopic surgery for renal pelvic stones, however, are still limited and not sharply defined. Few cases with medium to large renal pelvis stones are expected to benefit from it; for example, failed percutaneous renal access, stone burden that warranted open intervention, or associated congenital malformation. ⁶

Patients and Methods

From June 2002 to July 2009, patients with solitary renal pelvic stones were selected and randomly allocated to two groups. Group 1 included 55 patients who were treated by laparoscopic retroperitoneal pyelolithotomy (LRP) and group 2 included 50 patients who were treated by PCNL. Written informed consents were taken from the patients and approved by our Human Ethics Committee.

All patients had a single stone in a complete or partially extrarenal pelvis. The exclusion criteria were previous renal surgery, history of recurrent pyelonephritis, associated congenital anomalies, and morbid obesity. At presentation, all patients were assessed by spiral CT and urine cultures. All patients with positive urine cultures were treated appropriately before the procedure.

Results

Patient and stone characteristics are shown in Table 1. There were no statistically significant differences between the LRP and PCNL groups regarding patient characteristics, stone size, or preoperative UTI. Mean age was 41.2±11.7 years in the LRP group vs 38.5±11.9 years in the PCNL group. In the LRP group, 58.2% were male and 41.8% were female; in the PCNL group, there were 56% males and 44% females. The mean stone size in the LRP and PCNL groups was 2.4±0.4 cm vs 2.5±0.4 cm, respectively. UTI was associated in 12 (21.8%) patients in the LRP group and 13 (26%) patients in the PCNL group.

The operative and postoperative data are shown in Table 2. The mean operative time of the PCNL group was statistically significantly shorter than that of the LRP group (108.5±18.7 min vs 130.6±38.7 min, respectively). There were no statistically significant differences between the LRP and PCNL groups regarding estimated blood loss (166.4±98.3 mL vs 172.8±102.4 mL, respectively), the mean time to oral intake (1.6±0.5 d vs 1.1±0.3 d, respectively), mean time of postoperative hospital stay (4.5±1.9 d vs 4.4±1.4 d, respectively), and the mean time of postoperative analgesia (2.2±0.9 d vs 2.4±0.9 d, respectively) There was no statistically significant difference regarding the percentage of patients who needed blood transfusion because of significant bleeding between the RPL and PCNL groups (5.5% vs 6% respectively).

There was only one case from the laparoscopy group that was converted to open surgery because of uncontrolled bleeding. There was no statistically significant difference regarding the stone-free rate after 3 months between the two groups: It was 100% in the LRP group and 96% in the PCNL group. Postoperative fever was statistically significant higher in the PCNL (18%) group than in the RPL (5.5%) group. Regarding the RPL group, the mean drain time was 2.1±0.6 days; prolonged urinary leakage occurred in three cases (5.5%) cases because the inaccessible renal pelvis that was left opened.

Discussion

PCNL is considered the preferable treatment modality in the management of renal stones that are more than 3 cm or with surface area of more than 500 mm². ⁸ Although retroperitoneoscopic pyelolithotomy was first described in the early 1990s, it did not gain much popularity among urologists because of the long learning curve of the procedure and the well established PCNL technique. ⁹ Recently, successful laparoscopic management of renal stones have been described; however, the indications have not been yet defined and outcomes have not been compared with the established techniques, such as PCNL. ^2,6

In the current study, LRP was evaluated as a surgical monotherapy for the management of solitary renal pelvic stone and compared with PCNL, considered the preferred surgical management.

In our study, the preoperative data of both groups were homogenous with no statistically significant difference regarding the age and sex of patients and stone size as to which was favored to minimize the effect of any of them on the outcome of the surgical techniques. The mean operative time of the PCNL group was statistically significantly shorter than that of LRP, which is similar to the study by Meria and coworkers. ¹⁰ They reported the same difference between the two procedures in their study; however, their laparoscopic approach was transperitoneal. The longer time of LRP in our study was usually related to the long learning curve of laparoscopic pyelolithotomy as well as the time needed for intracorporeal suturing and delivery of the stone into the endobag. The mean operative time of LRP in our study, however, was acceptable and average in relation to many studies. ^2,10,11

There was no statistically significant difference between the two groups in the items of estimated blood loss, postoperative hospital stay, and postoperative analgesia. In the studies of Goel and Hamel, ⁹ Meria and associates, ¹⁰ and Tepeler and colleagues, ¹² they also compared many items between the two procedures and they found no significant difference regarding the previous items.

Open conversion was reported in one (1.8%) patient from the LRP group because of injury to an aberrant artery during dissection of the renal pelvis that could not be controlled laparoscopically. This rate of open conversion is relatively low in comparison to that of Sinha and Sharma, ¹³ who reported a 20% rate of open conversion and Goel and Hemal ⁹ , who reported open conversion in 2 of 16 (12.5%) patients who underwent LRP. The significant lower rate of conversion to open surgery in this study was related to the proper selection of cases and steady increasing of the learning curve.

There was statistically significant higher incidence of postoperative fever (18%) in the PCNL group in comparison with the LRP group (5.5%). Postoperative fever is the most common medical complication associated with PCNL (23%–25%), ¹⁴ and urosepsis develops in only a small fraction of these febrile patients (1%–2%). ¹⁵

The stone-free rate that was assessed after 3 months was higher in the LRP group in comparison with the PCNL group (100% vs 96%, respectively); however, this difference was statistically insignificant. In the study by Meria and coworkers, ¹⁰ they reported an nsignificant difference in the stone-free rate between laparoscopic transperitoneal pyelolithotomy (88%) and PCNL (82%). The high stone-free rate achieved in the current study was because of proper selection of cases, the intact removal of the stone in contrast to PCNL in which disintegration of the stone by the pneumatic lithotripsy may leave some residuals, and increasing of the learning curve. ⁶

Sinha and Sharma ¹³ reported their experience with LRP in 20 patients with a single renal pelvic stone, that was ideal for SWL or PCNL, but these options were not available; they reported the feasibility of LRP in the management of a single renal pelvic stone, especially when the stone is not complicated. They defined this as a new indication for laparoscopy in a developing country.

Although laparoscopic pyelolithotomy appears to be more invasive because three and sometimes four trocar punctures are needed compared with PCNL in which only a single hole is made, in PCNL there is transgression of the renal parenchyma with its potential of various complications, such as nephron damage and bleeding. ⁹ On most occasions, laparoscopy is nephron sparing–namely, pyelolithotomy compared with PCNL. ¹⁶

There is agreement about the role of laparoscopy in stone surgery by many authors, but in special situations, such as those associated with pelviureteral junction, stone in the pelvic kidney, and caliceal stones. ^2,9,17 Recently, Salvadó and coworkers ¹⁸ believe that this technique can be considered in cases of a large stone burden in different locations in the kidney.

Conclusion

LRP is considered a successful alternative therapy for PCNL in selected cases with a single large renal pelvic stone like those in the extrarenal pelvis in patients without a history of recurrent pyelonephritis or previous surgery, with nearly similar results to those of PCNL, which still suitable for most cases.