Long-term results of percutaneous nephrolithotomy for treatment of staghorn stones

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1 ; 2010 Laparoscopic and Robotic Urology LONG-TERM RESULTS OF PNL FOR STAGHORN STONES EL-NAHAS et al. BJUI Long-term results of percutaneous nephrolithotomy for treatment of staghorn stones Ahmed R. EL-Nahas, Ibrahim Eraky, Ahmed A Shokeir, Ahmed M. Shoma, Ahmed M. EL-Assmy, Nasr A. EL-Tabey, Hamdy A. EL-Kappany and Mahmoud R. EL-Kenawy Urology department, Urology & Nephrology Center, Mansoura University, Mansoura, Egypt Accepted for publication 1 September 2010 Study Type Therapy (case series) Level of Evidence 4 OBJECTIVE What s known on the subject? and What does the study add? Short-term results; as stone-free and complication rates; of percutaneous nephrolithotomy for treatment of staghorn stones. Long-term results of PNL; as recurrence rate and differential renal functional changes for treatment of staghorn stones with focus. To study long-term results of percutaneous nephrolithotomy (PNL) for treatment of staghorn stones. PATIENTS AND METHODS The records of patients who underwent PNL for staghorn stones between January 1998 and January 2008 were retrospectively reviewed. Patients who completed follow-up for one year or more were included. Follow-up with KUB and renal ultrasonography were performed every 3 6 months. Renal radioisotopic scan was performed for patients who had already undergone this study before doing PNL. RESULTS The study included 122 patients (69 male and 53 female) with mean age 47.6 ± 14.5 years (5 74). They underwent 126 PNL. Perioperative complications were encountered in 28 procedures (22%). The mean period of follow-up was 3.5 ± 2.3 years (1 11.3). Among 71 stone-free kidneys, 18 (25%) developed stone recurrence. Of 55 kidneys with residuals at the start of followup, 36 (65%) showed growth of these residuals. Preoperative and postoperative renograms were performed for 71 patients. At the last follow-up, differential GFR was stable in 53 (74.5%), improved in 12 (17%) and deteriorated in 6 (8.5%). Among patients with deteriorated renal function, 3 had undergone embolization to control severe bleeding, one developed secondary UPJO, and one had recurrent stone obstructing the kidney. CONCLUSION Long-term functional results of PNL for staghorn stones are satisfactory as 91.5% of kidneys showed stable or improved GFR. Long-term follow-up is mandatory especially for patients with residual stones. KEYWORDS percutaneous nephrolithotomy, staghorn stones, long term INTRODUCTION A staghorn calculus refers to a stone that occupies the renal pelvis and branches into several or all of the calices. According to the AUA guidelines for treatment of staghorn calculi, a newly diagnosed patient should be actively treated because untreated staghorn calculus is likely to destroy the kidney and cause life-threatening urosepsis [1,2]. Several modalities were described for treatment of staghorn stones including percutaneous nephrolithotomy (PNL) monotherapy, combinations of PNL and shock wave lithotripsy (SWL), SWL monotherapy, and open surgery. PNL has become the recommended primary treatment option because of its high efficacy in comparison with SWL and low morbidity when compared with open surgery [2 4]. The objectives of PNL in treatment of staghorn stones are complete stone clearance with minimum morbidity. However, multiple percutaneous accesses may be required to remove all stone branches [5]. These multiple-tracts PNL may lead to higher complication rates such as bleeding [6]. In spite of the large number of published series of PNL, authors had focused on shortterm results as stone-free and complication rates [7,8]. Moreover, when functional results of PNL were evaluated, the number of patients was small in some series[9], or it was described for all stone burden [10] or it was evaluated in special cases (after superselective angiographic embolization) [11]. Therefore, long-term results of PNL in patients with staghorn stones were scanty [12,13]. In this article, long-term results of PNL for treatment of staghorn stones in a tertiary care center are presented with focus on the recurrence rate and differential renal functional changes , doi: /j x x

2 LONG-TERM RESULTS OF PNL FOR STAGHORN STONES TABLE 1 Patients, urinary tracts and stone characteristics for 126 cases Variable N. % Patients (122) Male Female Urinary tract (126) Side: Right Left Bilateral Morphology: Normal Hydronephrosis Pyelonephrosis Previous Surgical treatment Stone composition (100) Struvite Uric acid Calcium oxalate Mixed Cystine 2 2 PATIENTS AND METHODS The computerized records of 238 patients who underwent PNL for treatment of staghorn stones between January 1998 and January 2008 were retrospectively reviewed to compile a database. Giant staghorn stones and those with markedly deformed caliceal anatomy were not included in the study because they were treated with open surgery. Borderline stones that branched to one major calyx were excluded from this study. This study included only patients who had staghorn stone present in the renal pelvis and branching to two (partial staghorn) or more major calices (complete staghorn) and who completed a minimum of 12 months follow-up. TECHNIQUE OF PERCUTANEOUS NEPHROLITHOTOMY Preoperative urinary tract infections were treated with culture specific antibiotics. Under the effect of general anesthesia and after placement of a ureteral catheter, percutaneous renal access was performed using multidirectional C-arm fluoroscopic guidance. PNL was completed in the same session except in patients with high serum creatinine or if the initial puncture drained purulent fluid. TABLE 2 Summary of operative and postoperative data of 126 PNL in treatment of staghorn stones Variable N. % Supracostal tracts Number of kidney punctures One Two Three Number of PNL sessions One Two Three Secondary procedures SWL URS Complications Bleeding or hematuria Perforation of the renal pelvis Urinary leakage Fever (38.5 C) Perirenal urinoma All planed tracts were placed to the desired calices and guidewires were fixed prior to dilatation of any tract. Dilation was performed using Alken s coaxial telescopic dilators to 30 French (F). The nephroscope passed through an Amplatz sheath. Ultrasonic or pneumatic lithotriptors were used for stone fragmentation. Intraoperative fluoroscopy and flexible nephroscopy were used for detection of residual stones. At the end of the procedure a nephrostomy tube of 22F was placed for 48 h. Non-contrast CT (NCCT) was performed after one day to evaluate stone-free rate. Residual stones that were accessible through the present nephrostomy tracts were managed by second-look PNL, while SWL was used for inaccessible residuals larger than 4 mm and follow-up was adopted for residuals smaller than 4 mm. Stone-free status was reevaluated after 3 months with NCCT for patients who required SWL. FOLLOW-UP Follow-up protocol included urinalysis, KUB and renal ultrasonography every 3 months for patients with residual stones and every 6 months for stone-free patients. IVU or NCCT was requested for patients with stone recurrence or with growth of residual fragments to decide the line of treatment. For functional evaluation of the affected kidney, renal radioisotope scan (using Technichium 99 MAG3) was performed for patients who had undergone this study before PNL. Changes of more than 5% from the initial GFR were considered as improvement or deterioration [14]. STATISTICAL ANALYSIS The data were analyzed using Statistical Package for Social Sciences, version 15 (SPSS, Chicago, IL). P value <0.05 was considered statistically significant. RESULTS The study included 122 patients who completed a minimum follow-up of 12 months) with mean age 47.6 ± 14.5 years (range 5 74). They underwent 126 PNL. Table 1 summarizes patients, urinary tracts and stone characteristics. In 38 procedures (30%) the nephrostomy tube was fixed by a radiologist to drain an infected kidney for few days before doing PNL. In the remaining 88 procedures (70%) the tract was established by an experienced endourologist and PNL was completed in the same session. All procedures were performed in prone position except for 3 morbidly obese patients who were treated in supine position. Table 2 summarizes operative and postoperative data. Multiple tracts were needed in 42 procedures (33%). Multiple sessions of PNL were performed in 36 cases (28.5%). Perioperative complications were encountered in 28 procedures (22%); some of them had more than one complication. Intraoperative bleeding was considered significant when necessitating stoppage of the procedure because of hemodynamic instability or interfering with proper vision. Three patients with postoperative hematuria had also intraoperative bleeding. Blood transfusion was needed in 18 patients (14%). Bleeding was successfully treated by clamping the nephrostomy tube and giving hemostatic drugs in 13 cases while 5 cases (4%) required angiographic embolization. Urinary leakage through the site of the nephrostomy was treated by fixation of double-j ureteral stents and urinoma was drained with percutaneous tube drain. Fever was treated with antibiotics and antipyretics. Secondary procedures for management of residual stones were performed for 34 cases (27%). The mean

3 EL-NAHAS ET AL. FIG. 1. Stone-free status during follow-up of 126 percutaneous nephrolithotomy of staghorn stones. After 3 months During Growth of Follow-up residuals: ( (65%) years) 55 Kidneys with residuals 126 Kidneys Same size of residuals: 19 (35%) 71 Stone-free Kidneys Stone Recurrence: free: 18 (25%) 53 (75%) number of procedures per case was 1.6 (range 1 4). The mean hospital stay was 5.1 days (range 2 21). The stone-free status of the 126 kidneys during follow-up is illustrated in Fig. 1. The mean period of follow-up was 3.5 ± 2.3 years (range ). Among the 71 stone-freekidneys, 18 (25%) developed stone recurrence after a mean period of 4.8 ± 2.3 years (range ) while the other 53 remained free of stones. Among 55 kidneys with residuals, 36 (65%) showed growth of these residuals after a mean period of 3.7 ± 2.3 years (range ) and 19 (35%) had the same size of the residual. Recurrent UTI during follow-up was present in 29 patients (23%). The treatment for stone recurrence or growth of residuals was in the form of SWL for 33 cases, PNL for 19 while nephrectomy was performed for one with poor renal function. Preoperative and postoperative renal radioisotope scans were performed for 71 patients. Staged PNL procedure was performed for 25 of them (33.8%). Multiple tracts were needed in 26 (36.4%) as two tracts were performed in 22 patients (31%) and three tracts in 4 patients (5.4%). Changes of differential GFR during follow-up are presented in Fig. 2. The differential GFR was stable in 53 kidneys (74.5%), improved in 12 (17%), while deterioration was observed in 6 (8.5%). In the 12 improved cases, the mean percentage of preoperative GFR had increased from 43 ± 14.5% to postoperative value of 53 ± 14.9%. While in the 6 deteriorated cases, the preoperative value of 41.5 ± 20.7% had decreased to 29.2 ± 21.8%. Of the 6 cases with deterioration of differential GFR, single percutaneous tract was performed for 4 cases, 2 tracts in one case and 3 tracts in the last patient. Deterioration of GFR in 5 of these 6 patients FIG. 2. Changes of percentages of renographic clearance (GFR%) during follow-up of 71 cases who underwent PNL for treatment of staghorn stones (Blue lines represent stable differential function, red lines represent deteriorated cases and black lines represent improved cases). GFR Preoperative Postoperative was attributed to development of complications as 3 had undergone embolization to control severe bleeding, one had urinary leakage after removal of the nephrostomy tube then developed secondary UPJO, and one had recurrent stone obstructing the kidney. IVU was performed for these 6 patients. The affected kidney was able to excrete the contrast in all cases except one with UPJO. The only significant correlation between changes of the differential GFR and preoperative, operative and postoperative variables was noticed with development of complications (r = 0.351, P = 0.003, Table 3). It was observed that multiple percutaneous tracts were comparable to single tract TABLE 3 Correlations between changes in differential GFR and preoperative, operative and postoperative variables Variable with regard to complications and GFR deterioration (Table 4). DISCUSSION R value The first report of PNL for treatment of staghorn stones was published by Clayman et al, in 1983 [15]. Since then there were marked improvements in the techniques and instruments as well as gaining much experience in PNL [5]. Currently, it is the treatment of choice for patients with large, complex and staghorn renal stones because of its high efficacy and low morbidity [1 5]. PNL is more challenging when used for treatment of staghorn stones. The AUA P value Gender* Side of stone* Renal morphology* Previous surgical treatment* Number of tracts* Skin puncture* Calyceal puncture* Number of PNL sessions* Complications* UTI Age BMI Preoperative creatinine Hemoglobin deficit UTI, Urinary tract infection. *Spearman correlation test. Pearson correlation test. TABLE 4 Comparison between the complications and GFR deterioration of PNL in cases requiring single versus multiple tracts Variable Single tract N/T (%) Multiple tracts N/T (%) P value Complications (126 PNL) 19/84 (22.6%) 9/42 (36.6%) GFR deterioration (71 Renal units) 4/45 (8.9) 2/26 (7.7) PNL, Percutaneous nephrolithotomy procedures; N, Number of affected cases; T, Total number of tested cases

4 LONG-TERM RESULTS OF PNL FOR STAGHORN STONES nephrolithiasis guidelines panel on staghorn calculi reported complication rates of 7% 27% and a transfusion rate up to 18% [2]. The complication rate of 22% and transfusion rate of 14% in the present study were within these ranges. The most dangerous complication was severe bleeding requiring angiographic embolization in 4% of cases. This high incidence of embolization was attributed to the complexity of the procedure and the need of multiple tracts in 33% of cases. Staghorn stone had been identified as an independent risk factor for post-pnl severe bleeding [6]and multiple tracts had been also detected as an independent risk factor for blood loss during PNL [16]. The 28.5% incidence of second look PNL and 27% incidence of secondary procedures in the present study highlight the importance of patient s counseling before PNL of staghorn stones. The surgeon must explain the need of multiple interventions to the patients. The main concern of this study was the evaluation of long-term effects of PNL in treatment of staghorn stones. We observed that it didn t affect the differential renal function in 64 of 71 patients (91.5%) who completed pre and post-pnl renal isotopic scans. Functional deterioration of the remaining 6 patients was attributed to development of complications or obstructing stones. Our results support that of Chatham et al., who reported preservation of the renal function (measured by renal isotope scanning) in 16 of 19 patients (84%) [9]. Moskovitz et al had measured the effect of PNL on regional and global function of the treated kidney using quantitative singlephoton emission CT (SPECT) measurement of Tc-dimercaptosuccinic acid (DMSA) uptake by the kidneys before then at 1.5 and 24 months after PNL. They had observed a decrease in the functional volume of the surgically treated region (i.e. upper, mid, lower zone), but the total uptake of injected dose was not significantly reduced after PNL [10]. In cases of staghorn stones with multiple large branches, percutaneous access to all the calices may be difficult through one tract. In these cases, multiple tracts PNL technique was reported as an alternative to single tract PNL with flexible nephroscopy or ureterorenoscopy [17]. The effect of single versus multiple tracts PNL on renal function was studied by Handa et al. They had found that multiple-tract access did not lead to a more severe reduction in renal function than single-tract access. They concluded that PNL didn t result in significant loss of renal function as measured by nuclear scintigraphy even when treating complex renal calculi or using multi-tract access [18]. In the present study, we had confirmed this finding because deterioration of renal function (measured by radio-isotope scans) was observed in 8.5% of cases and there was no correlation between changes of differential GFR and number of tracts. The retrospective nature of the present study was a limiting factor because there may be some bias in treatment strategies and the changes in differential renal function between preoperative and postoperative renograms were available for 56% of the patients. Another limitation was the lack of metabolic evaluation in many patients because stone analysis and metabolic tests were not routinely performed for all patients. An important finding during follow-up of our patients was the high rate of growth of residuals to form stones that required second intervention in 65% of cases with residual stones. The same was observed by Patterson et al [12]. Therefore, we recommend adopting a strict follow-up protocol for patients with residual stones because failure to achieve complete stone clearance risks rapid stone regrowth. On the other hand, the 25% of stone recurrence among our patients who were stone-free after treatment denotes that follow-up is also important for this category of patients. Moreover, studying stone composition and metabolic abnormalities among these patients may help in minimizing the recurrence rate by adopting the suitable stone metaphylaxis protocol especially for hyperuricosuria and cystienuria. CONCLUSIONS The long-term functional results of PNL for staghorn stones are satisfactory as 91.5% of kidneys showed stable or improved GFR. Long-term follow-up is mandatory especially for patients with residual stones because of the high rate of growth of them. CONFLICT OF INTEREST None declared. REFERENCES 1 Segura JW, Preminger GM, Assimos DG et al. 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