Multi-tract percutaneous nephrolithotomy combined with EMS lithotripsy for bilateral complex renal stones: our experience
© The Author(s). 2017
Received: 14 October 2016
Accepted: 24 February 2017
Published: 28 February 2017
The treatment of bilateral complex renal stones is a tough challenge for urologists. This study aimed to evaluate the efficiency and safety of bilateral ultrasonography-guided multi-tract percutaneous nephrolithotomy (PCNL) combined with EMS lithotripsy for the treatment of such cases.
Twenty-seven patients suffering from bilateral complex renal calculi underwent t bilateral multi-tract PCNL. The PCNL began with the establishment of percutaneous nephrostomy access, which was achieved under ultrasound guidance followed by stone fragment and removal by EMS lithotripsy. The same processes were then performed on the ipsilateral and contralateral renal units until the operation terminated. Sheaths left in situ to provide the tracts for the two-stage and the three-stage PCNL procedures. Peri- and postoperative clinical data were collected and analysed.
Renal stones of both sides were completely cleared within three PCNL sessions in 24 cases. Among them, four, thirteen, and seven cases underwent single, second-stage and third-stage procedures, respectively. The total stone-free rate was 88.9%. Three patients failed to receive complete stone clearance. Mean operation time was 78.7 (26–124) min, the mean estimated blood loss was 97.3 (30–250) ml, and the mean length of hospital stay was 18 (10–31) days. No patient required blood transfusion and postoperative fever occurred in 6 cases. Within the follow-up period, stone recurrence occurred in 6 patients.
Ultrasonography-guided multi-tract PCNL using EMS is an efficient method for the treatment of complex renal calculi. According to our experience, it is safe to make multiple tracts on both sides simultaneously.
KeywordsBilateral complex renal stones Multi-tract PCNL
Complex renal stones usually refer to staghorn calculi, multiple stones or those associated with anatomical or functional abnormalities. Due to the complicated etiological factors, large stone burdens, high operation risks and high recurrence, it is always a challenge for surgeons to treat such stones, especially those occur in bilateral kidneys. Since Fernström first described percutaneous nephrolithotomy (PCNL) under radiological control in 1976, it has been the standard method for the treatment of large renal stones . Complex stones often require multiple nephrostomy tracts, long operating time, and repeated procedures, which are associated with more access-related complications such as bleeding, infection and deterioration in renal function. Nevertheless, according to the current guidelines, PCNL is still the first-line choice for the management of large or staghorn renal stones [2, 3]. Owning to developments in the technique, it is possible to safely perform multi-tract PCNL on bilateral kidneys at one time. Over the past 4 years, we performed 27 bilateral multi-tract PCNL procedures for the treatment of complex renal stones; therefore, we evaluated the safety and efficacy of this approach.
Between October 2011 and November 2015, 27 patients (12 males and 15 females) with bilateral complex stones were admitted to our department. The mean age was 47.8 (41–63) years. All patients had history of renal stones ranging between 6 and 17 years. Eight patients had been treated by operations, five on one side, and three on both sides. All stones were detected by abdominal computerized tomography (CT), and plain film of kidney-ureter-bladder (KUB) as bilateral staghorn or multiple stones. The stone size varied from 2.5 to 8.6 cm. Three cases were associated with moderate to severe unilateral hydronephrosis and nine cases with moderate to severe bilateral hydronephrosis. Urological anatomical abnormalities were observed in five patients: three with ureter pelvic junction obstruction (UPJO) and two with duplex renal pelvis.
To evaluate the impact from times of PCNL on surgical morbidity, we divided the patients into 3 groups according to the operation sessions. We compared the hospital stay and blood loss among the 3 groups. Statistics analyses were performed using the software IBM SPSS statistics 22. The results were considered significantly different when the p value was less than 0.05.
Number of patients
Number of renal unit treated
Age, years, mean (range)
Preoperative body temperature, °C, mean (range)
Preoperative serum creatinine, umol/L, mean (range)
Mean stone size, cm
Urological anatomical abnormalities
Ureteropelvic Junction Obstruction (UPJO) 3
Double renal pelvis 2
Other relevant conditions
Spine deformation 1
Previous stone surgeries
One side 5
Both sides 3
Operative characteristics and results
Tracts in one renal unit, mean (range)
Number of patients who underwent different sessions of PCNL
One session 4
Two sessions 14
There sessions 9
Operation time, min, mean (range)
Estimated blood loss, ml, mean (range)
Hospital stay, days, mean (range)
Complete stone clearance rate within 3 sessions
Postoperative serum creatinine, umol/L, mean (range)
Clavien-Dindo Classification, Grade (Number)
I (21); II (6)
Follow-up, months, median (range)
The statistical analyses revealed that, there was no significant difference in terms of estimated blood loss among the 3 groups (p = 0.083). However, more sessions of surgeries were associated with longer hospital stay (p < 0.001).
Complex stones are extremely harmful to kidneys because they cause infection, atrophy, renal failure and cancerization. For treatment, multiple tracts are always required to achieve complete clearance and to avoid a second-look procedure such as ESWL or retrograde intrarenal surgery (RIRS). However, multiple tracts are often associated with a higher risk of bleeding . In addition, multi-tract PCNL is very difficult to learn and requires much experience, despite the improvements in devices and techniques over past decades . Some studies have suggested that open or laparoscopic stone surgery is an efficient method for the treatment of complex kidney stones, and is reported to be associated with higher one-session stone-free rate [7, 8]. However, PCNL can be repeated, whereas open or laparoscopic surgery would be increasingly difficult after the first procedure. Moreover, bilateral renal stones are difficult to be treated together in a single session by open or laparoscopic surgery. By contrast, in Cho’s study, multi-tract PCNL had similar safety and effectiveness as conventional single-tract PCNL in patients with complex stones . The AUA guideline also suggested that PCNL with multiple tracts was a safe and effective way for treating staghorn stones, with monotherapy stone-free rate of 79%, and acute complication rate of 15%.
A safe and efficient PCNL always begins with successful punctures, especially for complex stones. In our study, no severe complications occurred in any of the 27 patients, although we treated bilateral kidneys for each patient at a single time. We established the tracts under the guidance of ultrasonography. Compared with fluoroscopy, ultrasonography has advantages as it is more convenient without any radiation and it can present the three-dimensional structure of kidneys by turning the probe . Based on our experience, ultrasonography could clearly show hydronephrosis calyces as well as anatomical abnormalities. All tracts could be accurately placed in the line collecting the calyx neck middle and the corresponding calyceal fornix middle. Thus, the tracts provided the least traumatic and most direct access for the fragment of calculi. At the same time, the injury to adjacent viscera was avoided. Moreover, the whole procedure was performed under ultrasonography until dilation was complete, and it was confirmed whether there was any sign of bleeding. It is possible to totally avoid severe bleeding as long as precise punctures are achieved.
Multi-tract PCNL is still controversial. The major area of criticism has been safety during the process, as more than one tract dilatation is considered to be associated with a higher complication rate. Except for a higher risk of bleeding, there might be a significant rise in serum creatinine and drop in creatinine clearance after multi-tract PCNL , which means that multiple tracts might cause damage to renal function. However, in our study, only three patients experienced increased postoperative serum creatinine, and based on other studies, there was no evidence to indicate that multiple tracts led to renal insufficiency [12–14]. Moreover, in a number of studies, when compared with single-tract PCNL, no significant difference was reported in terms of complications [9, 11]. In our study, no patients suffered severe perioperative and postoperative complications, and no patients required blood transfusion, showing that more than one tract in a single operation is not always accompanied by high risk. In Singla’s study, the maximal number of tracts used in a single renal unit could be up to six with acceptable morbidity . However, we have to admit, the safety should necessarily be the first principle when we treat complex stones, especially for bilateral stones. Although bilateral PCNL is more efficient and can be performed in both children and adults, it carries a higher rate of overall complications, such as fever, persistent pain, acute renal failure and vomiting, than unilateral PCNL . In addition, once there is hematuria or leucocyturia after bilateral surgery, we cannot determine which is the disease-causing kidney. In consideration of these risks, we performed a careful assessment for every patient before operation to ensure that bilateral PCNL could proceed smoothly. We kept the operation time within 2 h and always started in the renal unit that seemed easier to treat, so that the risk of sepsis was controlled. For each patient, the first tract is the main one, through which we could clear most of the stone burden and relieve the obstruction. Once any severe bleeding or pyonephrosis was found, the operations were stopped immediately, and the tracts remained for the secondary procedure. On the other hand, we acknowledge that more sessions of surgery would inevitably prolong the mean hospital stay, which means more financial cost and higher risk of nosocomial infection, because of the necessary preparation before each session of PCNL, particularly for those with urinary infection. Given these factors, more experience is required to improve the efficiency without any decrease in safety.
For the fragmentation of complex stones, we used the fourth-generation EMS, applying pneumatic and ultrasonic energy together. The stone fragmenting and removal can be carried out at the same time through vacuum suction. The normal saline solution was hung approximately one metre higher than the renal location, which poured naturally as the washing flow, instead of using a pump. Combined with the suction system, a clear surgical field was provided with a low intrapelvis pressure. Using this device, the operation time was shortened and the safety together with efficacy was increased. In our study, only six patients developed postoperative fever, but recovered quickly. In Wang’s study, EMS was even safe for the treatment of calculous pyonephrosis, which was considered as a contraindication of PCNL .
Even though most patients also needed more than one stage of operation, multi-tract PCNL significantly improved the clearance efficacy. The totally stone-free rate was 88.9% within three sessions of PCNL, while the recurrence rate was 6/23 within 42 months. Complex stones often result from inherent existing factors such as infection, metabolic disturbance or anatomical abnormality, which occurred in five patients in our series, indicating that prevention is a much more important and difficult task for urologists. Although multi-tract PCNL is an appropriate option to clear complex stones from kidneys with anatomical abnormality, it is of limited value to reduce the recurrence risk. Perhaps, the concomitant of laparoscopic and endoscopic treatment would be the further direction for the treatment of such cases [18, 19].
Ultrasonography together with pneumatic and ultrasonic endoscopic lithotripter is a widely used device in China for PCNL. With their help, multi-tract PCNL is an efficient and safe method for the treatment of bilateral complex renal stones. Given the limitation of the sample size and the retrospective nature of our study, more multi-center, randomized control studies with large sample size and high quality are required.
Electro Medical Systems
Extracorporeal Shock Wave Lithotripsy
Retrograde intrarenal surgery
Availability of data and materials
All data and materials can be obtained by contacting the corresponding author.
HY and TSL conceived and designed this study. TSL, GW, BTT, XDL, SGL and YD carried out surgeries on patients. XDL, YD, CMZ and HY contributed to the follow-up questionnaire. CMZ, HY, GW, BTT and SGL participated in data acquisition and interpretation. CMZ performed the statistics analyses and drafted the manuscript. HY, TSL and GW critically reviewed the manuscript. All the authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Consent for publication
Ethics approval and consent to participate
This study was a retrospective review of cases of patients treated at the hospital. It was approved by the ethics committees of Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine (Number: csky201401). All patients gave written informed consent for the multi-tract PCNL procedures and the use of their information in our research as well according to the Helsinki II declaration.
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