The optimal minimally invasive percutaneous nephrolithotomy strategy for the treatment of staghorn stones in a solitary kidney

Transcription

1 Urolithiasis (2016) 44: DOI /s ORIGINAL PAPER The optimal minimally invasive percutaneous nephrolithotomy strategy for the treatment of staghorn stones in a solitary kidney Chenli Liu 1 Zelin Cui 1 Guohua Zeng 1 Shaw P. Wan 1 Jiasheng Li 1 Wei Zhu 1 Tao Zeng 1 Yang Liu 1 Received: 2 March 2015 / Accepted: 7 July 2015 / Published online: 25 July 2015 Springer-Verlag Berlin Heidelberg 2015 Abstract The objective of the study was to analyze the treatment outcomes for staghorn stones in patients with solitary kidney using either the single-tract or the multitract minimally invasive percutaneous nephrolithotomy (MPCNL). We retrospectively reviewed 105 patients who underwent MPCNL for staghorn calculi in solitary kidney from 2012 to The patients who underwent the singletract approach (71 patients) were assigned to Group 1. The 34 patients who underwent the multi-tract approach (34 patients) were assigned to Group 2. We recorded and compared the patient s demographics, intraoperative parameters, and post-operative outcomes. We also analyzed any complications as a result of the particular procedure, as well as any resulting stone-free rates (SFRs). The mean number of access tracts was 2.38 ± 0.70 (range 2 4) for Group 2. The mean operative time was longer for Group 2, p = The initial SFR was 52.1 % for Group 1 and 47.1 % for Group 2 after the one-session procedure, p = 0.63.The final SFR improved to 83.1 and 79.4 % for both groups following auxiliary treatment, p = The mean hemoglobin drop was higher in Group 2 as compared to Group 1, p < There was no significant difference in the change of mean serum creatinine in either group. There were fewer overall complications in Group 1 than in Group 2 (23.9 vs %). Almost half of the patients who underwent multi-tract MPCNL required an additional procedure to achieve satisfactory stone clearance. The results showed Chenli Liu and Zelin Cui contributed equally to this study. * Guohua Zeng gzgyzgh@vip.tom.com 1 Department of Urology, Guangdong Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China that single-tract MPCNL might be a better treatment option for staghorn stones in a solitary kidney with the same therapeutic outcome, but with less complications. Keywords Complication Percutaneous nephrolithotomy (PCNL) Staghorn calculi Solitary kidney Urolithiasis Introduction We have been using minimally invasive percutaneous nephrolithotomy (MPCNL) for the treatment of staghorn stones for many years. We had previously reported that MPCNL is a safe and effective therapeutic modality for this condition [1]. Nevertheless, using MPCNL in the management of staghorn stones is technically complicated, time consuming, and taxing to both the patients and the surgeons. Staghorn stones in solitary kidneys pose additional challenges. These patients tend to be more fragile, the margin for error is smaller, and a lot more would be at stake if surgical complications occur. The surgeon must balance the desire for high treatment success to the need of minimizing the risks to the patient. Currently, there are two prevailing philosophies in our department for the optimal treatment of the staghorn stones in solitary kidney. The first approach is to debulk the stone using a single nephrostomy tract to minimize potential complication. Patients were then reassessed few days later and a secondary procedure was offered to achieve satisfactory outcome. The drawback of this approach is the necessity by design to commit the patients to an additional procedure, a second anesthesia, and likely more cost. The second approach is to achieve higher success initially by employing as many nephrostomy tracts as deemed necessary in a sequential fashion. The avoidance of a second procedure, a second anesthesia, and the likelihood

2 150 Urolithiasis (2016) 44: of less cost might well justify the potential of higher risks. The debate rages on. Hence, we decided to do a retrospective analysis of the records of the patients who underwent treatment for staghorn stones in solitary kidney using either strategy to identify the better of the two modalities. Methods We retrospectively reviewed the data of 105 patients with staghorn stones in a solitary kidney who underwent MPCNL in our institution from July 2012 to June All the patients in this study were 18 years or older. 71 patients who underwent the single-tract procedure were assigned to Group 1 and 34 patients who underwent multiple-tract procedure in a single session were assigned as Group 2. The decision on which of these approaches to be used was generally made by the operating surgeon based on the stone burden, stone distribution in the collecting system, the likelihood of removing the stones in a single session, and the patient s preference. We had obtained the Ethics Review Board approval for this study. Patients demographics, including age, sex, body mass index (BMI), laterality, stone location and burden, previous stone intervention history, and co-morbidities were recorded. Preoperative laboratory tests included urine analysis, serum creatinine, CBC, platelet count, coagulation studies, and if indicated urine culture and sensitivity. Urinary tract ultrasonography, plain radiography (KUB), and computed tomography (CT) were performed to evaluate the kidney and surrounding organs in each patient. Intravenous urography (IVU) was obtained in selected cases. The stone surface area was calculated using radiological studies [2]. Prophylactic antibiotics were administered 1 h preoperatively to all the patients without evidence of urinary tract infection, whereas patients with culture-proven bacteriuria were treated with antibiotics according to the antibiogram until the urine culture turned negative before the surgery. We categorized the staghorn stones into either partial staghorn stone (filled the renal pelvis or at least two or more calyces) or complete staghorn stone (occupying the renal pelvis and all of the calyceal system or filled 80 % of the pyelocalyceal system). MPCNL was usually performed under general anesthesia. We had previously published the details of our MPCNL procedure [1]. Briefly, a 5 Fr ureteral catheter was first inserted in retrograde fashion in the lithotomy position. The patient was then turned into a prone position. Percutaneous access was always established by the urologist under either fluoroscopy or sonographic guidance. After proper renal puncture, the nephrostomy tract was dilated using fascial dilators up to Fr and a matching nephrostomy sheath was placed. Nephroscopy was performed using a rigid 8.5/13 Fr endoscope. Pneumatic lithotripter and/or holmium laser were used for stone fragmentation. In patients who underwent the planned multi-tract procedure, additional access tracts were created as deemed necessary during the same session. A 16 Fr nephrostomy tube or tubes and a 6 Fr ureteral stent were routinely placed for each of the patients. Stone clearance was assessed with KUB or non-contrast CT scan h after the surgery. The nephrostomy tube or tubes were removed when the drainage had become grossly clear. Patients were generally discharged the day after removal of the nephrostomy tubes. The ureteral stents were removed 2 4 weeks later. A second-look or repeat MPCNL, SWL, and ureteroscopy (URS) were offered as auxiliary procedures in patients with significant residual stones after the initial procedure. Recorded operative parameters included the site of puncture, number of the access, operative time, SFR, auxiliary procedure, and intraoperative and postoperative morbidities. Operative time was defined as the time from the first renal puncture to the completion of the stone removal. Initial SFR was defined as either complete stone clearance or with clinically insignificant residual stone ( 4 mm) on KUB or CT taken at h after the procedures. The final SFR was defined to be the same as the initial SFR, but at 1 month postoperatively and after any and all auxiliary procedures. The selection of the type of auxiliary procedures depended on the burden and the distribution of the residual stones. The auxiliary procedures were generally performed 3 5 days after the initial MPCNL and when the nephrostomy tube drainage had become grossly clear. Complications were recorded according to the modified Clavien classification system [3]. The preoperative clinical parameters, intraoperative data, and postoperative outcomes in both groups were compared using the Student s t test for quantitative variables and Chi square test for qualitative variables. Statistical significance was presumed for p values <0.05. Results The mean age, sex, and BMI were similar in the two groups. There were also no significant differences in terms of partial or complete staghorn stones, comorbidity, prior surgery, and hydronephrosis between these two groups, p > 0.05 (Table 1). The stone surface area tended to be larger in Group 2, but the values were not statistically significant. The mean preoperative serum creatinine was alike in both Group 1 (1.43 ± 0.45 mg/dl) and Group 2 (1.41 ± 0.50 mg/dl), p = The etiologies of the solitary kidney in Group 1 included nephrectomy in 16 patients, non-functioning of the contralateral kidney

3 Urolithiasis (2016) 44: Table 1 Patient characteristics Parameters Group 1, single tract Group 2, multiple tracts p value No. of patients, (n) 74 Gender, male, n (%) 51 (71.8) 19 (55.9) Mean age (year) ± ± BMI (kg/m 2 ) ± ± Comorbidities, n (%) 14 (19.7) 8 (23.5) Right/left Stone surface area (mm 2 ) 1965 ( ) 2103 ( ) Stones classification, n (%) Partial staghorn 41 (57.8) 22 (64.7) Complete staghorn 30 (42.3) 12 (35.3) Surgery history, n (%) 14 (19.7) 10 (29.4) Hydronephrosis, n (%) G0 19 (26.8) 12 (35.3) G I III 52 (73.2) 22 (64.7) Types of solitary kidney, n (%) Nephrectomy 16 (22.5) 0 Non-perfused 47 (66.2) 34 (100) Congenital 8 (11.3) 0 Stone composition (%) Calcium based 50 (70.4) 21 (61.8) Struvite 9 (12.7) 7 (20.6) Uric acid 12 (16.9) 6 (17.6) Preoperative creatinine (mg/dl) 1.43 ± ± BMI body mass index Table 2 Operative and postoperative data Parameters Group 1, single tract Group 2, multiple tracts p value Mean number of tracts (n) ± 0.70 <0.001 Site of puncture (%) Supracostal 43 (60.5) 49 (58.3) Infracostal 28 (39.4) 35 (41.7) Mean operative time (min) ± (25 130) ± (40 195) Mean hospitalization (days) 7.9 (2 24) 9.1 (4 21) Stone-free rate (%) Initial SFR 37 (52.1) 16 (47.1) Final SFR 59 (83.1) 27 (79.4) Auxiliary procedures (%) 25 (35.2) 15 (44.1) PCNL 21 (29.6) 12 (35.3) PCNL 21 (29.6) 12 (35.3) SWL 2 (2.8) 3 (8.8) URS 2 (2.8) 0 Mean hemoglobin drop (g/dl) 1.3 ± ± Pre post creatinine (mg/dl) 0.03 ± ± PCNL percutaneous nephrolithotomy, SWL shockwave lithotripsy, URS ureteroscopy (glomerular filtration rate <15 ml/min) in 47 patients, and congenital absence of the contralateral kidney in 8 patients. All patients in Group 2 had non-functioning contralateral kidneys. The stone compositions comprised calcium oxalate, struvite, and uric acid. There was no significant difference between the two groups, p = All of the surgical and hospitalization data are displayed in Table 2. The mean number of access tract was

4 152 Urolithiasis (2016) 44: Table 3 Complications Parameters Group 1, single tract Group2, multiple tract p value Infection-related complications (%) 12 (16.9) 8 (23.5) Fever (>38 C) (Clavien grade I) (%) 5 (7.0) 6 (17.6) SIRS requiring additional antibiotics (Clavien grade II) 6 (8.5) 2 (5.9) (%) Septic shock (Clavien grade IVa) (%) 1 (1.4) 0 Hemorrhage-related complications (%) 5 (7.0) 6 (17.6) Blood transfusion (Clavien grade II) (%) 4 (5.6) 6 (17.6) Embolization (Clavien grade IIIa) (%) 1 (1.4) 0 Urine leakage < 12 h (Clavien grade II) (%) 0 1 (2.9) Total (%) 17 (23.9) 15 (44.1) ± 0.70 (range 2 4) for Group 2. Access using the supracostal approach was similar in both groups, 60.5 versus 58.3 %, p = The mean operative time was significantly less in Group 1 than Group 2, 72 ± 28.6 versus 86.6 ± 26.8 min, respectively, p = The mean change in serum creatinine showed no statistical significance, 0.03 ± 0.33 mg/dl for Group 1 and 0.02 ± 0.29 mg/dl for Group 2, p = The initial SFR were surprisingly comparable in both Groups 1 and 2, 52.1 versus 47.1 % respectively, p = Among the patients who were not stone free, 21 out of the 71 patients (30 %) of Group 1 required second PCNL. The second PCNL was done either through the original tract or through new tracts. 12 out of 34 patients (35 %) in Group 2 required second PCNL. The second PCNL was also performed through the same tracts and in selected cases through additional new tracts. Other auxiliary procedures included two (3 %) SWL and two (3 %) URS in Group 1. Three (9 %) SWL were recorded in Group 2. After the completion of additional treatment, the final SFR increased to 83.1 % for Group 1 and 79.4 % for Group 2, p = The postoperative hospital stay was similar, 7.9 (2 24) days and 9.1 (4 21) days, for Group 1 and 2, p = Complications encountered during the perioperative period for both groups are listed in Table 3. Most of the complications were classified as Clavien grades I and II. The infection-related complications which included fever (>38 C), SIRS requiring additional antibiotics, and septic shock were comparable in the two groups, p = The mean hemoglobin drop was significantly less in Group 1 than Group 2, 0.13 ± 0.13 g/dl versus 0.22 ± 0.16 g/ dl, p < The blood transfusion rate was higher for Group 2, but did not reach statistical significance. Four patients (5.6 %) in Group 1 and six patients (17.6 %) in Group 2 had a blood transfusion, p = One patient in Group 1 required super selective arterial embolization for uncontrolled bleeding. Urine leakage from the percutaneous access was noted in one patient in Group 2 after the removal of the nephrostomy tube. It resolved in less than 12 h with local compression. Discussion Staghorn stone is a challenging disease and is difficult to treat by any of the proven modalities. Staghorn stone is often referred to as stone cancer. It has a tendency to recur and lead to further renal destruction. To render these patients stone free should be the sine qua non goal for its treatment. MPCNL has been proven to be a safe and effective treatment modality for staghorn stones including patients with solitary kidney [4]. It however is a very demanding procedure and has a relatively long learning curve. In our present study, an overall success rate of 83.1 % for single-tract and 79.4 % for multiple-tract MPCNL was achieved following the completion of all auxiliary procedures. These results were in line with the result of 83 % published by Maghsoudi et al. [5]. However, in our patients managed with multi-tract approach, the initial stone clearance rate of 47.1 % was lower than the 81.1 and 56.9 % reported by Akman et al. and Desai et al. in their series using standard PCNL [6, 7]. One possible explanation for our inferior result could be the natural inclination for the surgeons to be more conservative during the operation when dealing with solitary kidney. Cho et al. [8] also reported that the SFR was 50 % for multiple-tract PCNL and 74.7 % for single-tract PCNL after one surgical session, and there was a higher rate of auxiliary treatments in patients with multi-tract PCNL. A large-scale study reported by Desai et al. [9] demonstrated the SFR in multiple-tract PCNL was not higher than single-tract PCNL procedures, 84.1 versus 86.4 %, respectively. In the present study, percutaneous access was always established by the urologist under either fluoroscopic or sonographic guidance. The choice of which modality to use was made mainly at the discretion of the treating urologist

5 Urolithiasis (2016) 44: based on his or her expertise and preference. Sonographic guidance has the inherent advantages of having no radiation exposure as well as the visualization of the peripheral viscera. However, it is harder to access the desired calyx when there is no hydronephrosis. Our indications for sonographic guidance generally include: hydronephrosis, simple stones, radiolucent stones, surgeon s training and preference, and complex stone that could benefit from the combination of fluoroscopic and sonographic guidance. The superior and posterior calyx can allow better access to the renal pelvis and to most of the calyces with minimal torque and angulation; thus it might lead to better stone clearance and less bleeding [10]. In this study, upper calyceal access was used in 60.5 % of single-tract MPCNL and 58.3 % in multi-tract MPCNL. However, we did not have a single incidence of hydro- or pneumothorax. The data of the present study showed that patients who underwent multi-tract treatment in one session had a higher frequency of complications, with an overall complication rate of 23.9 % for single-tract and 44.1 % for the multi-tract MPCNL. This was similar to the other previously published data of % [11, 12]. In the study of Akman et al. [6], it was reported that the overall complication rates were 37.9 % in multiple-tracts PCNL and 16.7 % for single-tract PCNL. They reported that the mean drop in hemoglobin was significantly higher in the multitract procedure as compared to single-tract PCNL, and blood transfusion was required in 13.9 and 28.4 % of the patients who underwent single-tract and multi-tract treatments, respectively. Netto et al. [12] also found that bleeding requiring blood transfusion was significantly greater in the multiple access group. In the present study, the mean drop in hemoglobin of 2.2 g/dl with multi-tract MPCNL was significantly higher than that of 1.3 g/dl with the single-tract procedure. The reasons for the higher blood loss were likely due to the longer operative time and the multiple punctures and dilations required in the multi-tract group. Although there was no statistical difference in the blood transfusion rate among our two groups, there was a trend toward higher blood transfusion using the multipletract approach. This was similar to a previous report by Desai et al. [9]. Infection complication is also a common and troublesome issue with PCNL. Many factors such as diabetes, positive preoperative urine culture, infection stones, staghorn stones, multiple punctures, and length of operative time had all been proven to be predictors for postoperative infection complications [13, 14]. The present study showed that there was no significant difference in the rate of infection complication, including SIRS and septic shock, between both approaches. However, we did find that the presence of hydronephrosis was a predictor for infection-related complications. 11 out 12 of our patients who experienced infection complications in single-tract 153 and six out eight patients in multi-tract MPCNL were documented to have hydronephrosis. The literature has not been consistent in reporting the impact of multiple-tract PCNL on renal function. Akman et al. [6] compared the morbidity of multiple-tract versus single-tract PCNL in 413 patients and found no significant difference in the mean changes in the creatinine values between the groups. Fayad and coworkers [15] evaluated the effect of multiple-tract PCNL on renal function and found that patients with baseline renal impairment (serum creatinine level 1.4 mg/dl) experienced worsening of serum creatinine and deterioration of GFR. Our current retrospective analysis showed that the change of mean serum creatinine was not statistically significant between the two groups (p = 0.974). In summary, the morbidity seemed to be higher in patients with the multiple-tract PCNL; yet, the stone-free rates (SFR) were not any better than the single-tract procedure. Staged PCNLs were commonly required for both approaches. In addition, the mean duration of the fluoroscopic and the operative time were longer in the multi-tract procedure [6]. Therefore, aggressive PCNL using multiple tracts in a single session in an attempt to achieve maximum stone clearance might not be a prudent choice. This was not a prospective randomized study and consequently there would be the unavoidable selection bias. However, we believed the selection bias tended to err at underestimating the complexity of the staghorn stones; thus it would lead to the belief that by engaging a multi-tract approach one could achieve higher therapeutic success. Conclusion MPCNL is a safe and effective treatment modality for staghorn stones in patients with solitary kidney. These patients, however, will frequently require a second procedure to achieve satisfactory results regardless of the initial treatment plan or intention. The most common second procedure is a repeat MPCNL under separate anesthesia. There is a natural desire for the patient as well as the surgeon to have the treatment completed in a single session. Nevertheless, it is probably not a realistic expectation. Our data seemed to indicate that a more conservative approach of using a single nephrostomy tract to debulk the stone followed by reassessment and a second procedure few days later could achieve same therapeutic outcome with less complications. It would therefore be a more sensible choice. With our retrospective data in place, we are now ready to go forward with a prospective randomized study. Acknowledgments This work was financed by grants from the National Natural Science Foundation of China (Nos and

6 154 Urolithiasis (2016) 44: ), colleges and universities in Guangzhou Yang Cheng scholars research project (No. 12A017S) and Science and Technology Project in Guangzhou (the People s Livelihood Special Major Science and Technology, No ). Compliance with ethical standards Conflict of interest The authors of this study disclose no conflicts of interest. References 1. Zeng G, Zhao Z, Wan S et al (2013) Minimally invasive percutaneous nephrolithotomy for simple and complex renal caliceal stones: a comparative analysis of more than 10,000 cases. J Endourol 10(27): Tiselius HG, Andersson A (2003) Stone burden in an average Swedish population of stone formers requiring active stone removal: how can the stone size be estimated in the clinical routine? Eur Urol 3(43): Tefekli A, Ali KM, Tepeler K et al (2008) Classification of percutaneous nephrolithotomy complications using the modified Clavien grading system: looking for a standard. Eur Urol 1(53): Lai D, He Y, Dai Y, Li X (2012) Combined minimally invasive percutaneous nephrolithotomy and retrograde intrarenal surgery for staghorn calculi in patients with solitary kidney. PLoS ONE 10(7):e Maghsoudi R, Etemadian M, Shadpour P, Radfar MH, Ghasemi H, Shati M (2012) Number of tracts or stone size: which influences outcome of percutaneous nephrolithotomy for staghorn renal stones? Urol Int 1(89): Akman T, Sari E, Binbay M et al (2010) Comparison of outcomes after percutaneous nephrolithotomy of staghorn calculi in those with single and multiple accesses. J Endourol 6(24): Desai M, De Lisa A, Turna B et al (2011) The clinical research office of the endourological society percutaneous nephrolithotomy global study: staghorn versus nonstaghorn stones. J Endourol 8(25): Cho HJ, Lee JY, Kim SW, Hwang TK, Hong SH (2012) Percutaneous nephrolithotomy for complex renal calculi: is multi-tract approach ok? Can J Urol. 4(19): Desai M, Ganpule A, Manohar T (2008) Multiperc for complete staghorn calculus. J Endourol 9(22): Munver R, Delvecchio FC, Newman GE, Preminger GM (2001) Critical analysis of supracostal access for percutaneous renal surgery. J Urol 4(166): Singla M, Srivastava A, Kapoor R et al (2008) Aggressive approach to staghorn calculi-safety and efficacy of multiple tracts percutaneous nephrolithotomy. Urology 6(71): Netto NJ, Ikonomidis J, Ikari O, Claro JA (2005) Comparative study of percutaneous access for staghorn calculi. Urology 4(65): Eswara JR, Shariftabrizi A, Sacco D (2013) Positive stone culture is associated with a higher rate of sepsis after endourological procedures. Urolithiasis 4(41): Kreydin EI, Eisner BH (2013) Risk factors for sepsis after percutaneous renal stone surgery. Nat Rev Urol 10(10): Fayad AS, Elsheikh MG, Mosharafa A et al (2014) Effect of multiple access tracts during percutaneous nephrolithotomy on renal function: evaluation of risk factors for renal function deterioration. J Endourol 7(28):