Original Paper
Urologia
Received: May 8, 2014 Accepted after revision: September 16, 2014 Published online: February 17, 2015
Urol Int DOI: 10.1159/000368373
Internationalis
Is Micropercutaneous Nephrolithotomy Technique Really Efficacicous for the Treatment of Moderate Size Renal Calculi? Yes Tuna Karatag Ibrahim Buldu Ramazan Inan Mustafa Okan Istanbulluoglu Mevlana University, Konya, Turkey
Key Words Micropercutaneous nephrolithotomy · Safety · Feasibility
rolithotomy should be considered for the treatment of moderate-sized renal stones as an alternative to SWL and RIRS failures and also may be considered even primarily. © 2015 S. Karger AG, Basel
© 2015 S. Karger AG, Basel 0042–1138/15/0000–0000$39.50/0 E-Mail [email protected] www.karger.com/uin
Introduction
Since its introduction in 1976, percutaneous nephrolithotomy (PNL) has developed considerably as a result of technological refinements and surgical experiences to minimize postoperative pain, morbidity, and hospitalization [1]. Although many kinds of treatment modalities such as SWL, RIRS, and PNL ranging from noninvasive to invasive have been suggested for the moderate-sized renal calculi, optimal treatment can be changed according to the size and the location of stones and characteristics of the patient. After introduction of optic puncture system in renal stone treatment in 2011 [2], micro-percutaneuos nephrolithotomy procedures have become a choice for the treatment of moderate-sized kidney stones with the advantages of providing single-step percutaneous renal access under direct vision through a 4.8 SFR sheath. Although some data, including comparative results, in order to determine the appropriate management with highest stone-free and less morbidity rate are available, the initial reports have suggested that micro-percuTuna Karatag, MD Department of Urology, Faculty of Medicine Mevlana University TR–42200 Konya (Turkey) E-Mail tunakaratag @ gmail.com
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Abstract Objective: To present our clinical experiences with micropercutaneous nephrolithotomy in the treatment of moderatesized renal calculi from a single center. Methods: We retrospectively evaluated the patients with moderate-sized renal calculi who underwent micro-percutaneous nephrolithotomy between December 2012 and Septermber 2013. Results: A total of 68 patients and 70 renal units underwent microperc procedure. Mean age of patients was 41.4 ± 18.8. The mean stone size was 122 ± 83 mm2. The operations were performed under spinal anesthesia in 89.7% of the patients. Stone-free rate was 95.7 % (67/70). Clinically significant residual fragments were observed in three patients. The average duration of operation and mean fluoroscopy time was 40 ± 23 min and 108 ± 72 s, respectively. The mean postoperative drop in hemoglobin was 0.95 ± 0.7 while no patient required blood transfusion. Patients were discharged after an average hospitalization time of 27.5 ± 12.4 h. A total of 4 complications (5.7%), including urinary tract infection (Clavien I) in one patient and renal colics requiring stent insertion (Clavien IIIa) in three patients, were observed postoperatively. Conclusion: Microperc technique is safe, feasible, and efficacious. We suggest that micro-percutaneous neph-
Color version available online
Color version available online
Fig. 1. Microperc system with a three-channel connector.
Fig. 2. Dust particle removal out of 7 SFR urethral catheter.
taneous nephrolithotomy technique was feasible, safe, and efficacious for the small and moderate-sized kidney stones [3–5]. In this study, we present our clinical experiences of microperc surgery for the treatment of the moderate-sized renal calculi, commonly performed under spinal anesthesia as distinct from other reports.
puncture. Percutaneous renal access to the caliceal fornix was achieved using a 16-gauge needle with the C-arm fluoroscopy guidance; inner and outer puncture shafts of the 4.8 SFR ‘allseeing needle’ microperc system (PolyDiagnost, Pfaffenhofen, Germany) were placed and after taking out the inner shaft, a three-way connector allowing the insertion of a 0.9-mm flexible micro-optic, laser fiber, and irrigation system was attached to the outer tip of the shaft (fig. 1). Usually, the stone containing calyx was targeted; if the stone was in the renal pelvis, either middle or lower calyceal puncture was preferred. The stone fragmentation was usually achieved using a 200-μm holmium: YAG laser fiber in the settings of 0.2 J at 50 Hz. Irrigation was carried out using a mechanical pump with foot pedal control. Saline irrigation aids the maintenance of proper vision and removal of the stone debris during the surgery and provides the flush out of the stone fragments and dust particles through the ureteral catheter continuously (fig. 2). Intermittent manual suction also can be done through the ureteric catheter to reduce the intrarenal pressure. We did not put any nephrostomy catheter while the ureteric catheter was left in place postoperatively. The patients were routinely discharged after removal of the urethral and ureteral catheter on the first postoperative day if there was no complication. All of the patients underwent a radiological assessment with KUB on the first postoperative day. Success was defined as a non-residual fragment on X-ray KUB images of the first month of follow-up. Clinically insignificant residual fragments (CIRF) were defined as asymptomatic fragments ≤4 mm [6]. The postoperative complications were evaluated using Clavien grading system [7].
We retrospectively reviewed the patients with moderatedsized renal calculi who underwent microperc nephrolithotomy procedure in our clinic between December 2012 and September 2013. Our series consisted of the patients with a history of failed SWL and RIRS treatment and the patients with moderate-sized stones larger than 1 cm primarily according to the patient preference. We excluded the patients who underwent standard PNL for the opposite renal stone at the same time. The patients’ characteristics were enrolled in terms of age, BMI, blood parameters, stone burden, and related parameters. Informed consent form was obtained from each patient before surgery. Radiological evaluation was performed with computed tomography for all patients. The patients with positive urine cultures were also treated with appropriate antibiotics preoperatively. Technique of Microperc Procedure Although the procedure can be carried out under general anesthesia if required, we commonly performed our procedures under regional anesthesia. A 7 SFR ureteric catheter was inserted through the ureter into the renal pelvis under cystoscopic and fluoroscopic guidance in the lithotomy position. Then, the patient was turned to the prone position after fixing the ureteric catheter to the urethral catheter. The pelvicalyceal system was filled with diluted contrast agent injected retrograde through the ureteric catheter. This creates a mild hydronephrosis and demonstrates the configuration of pelvicalyceal system, which aids calyceal
2
Urol Int DOI: 10.1159/000368373
Results
A total of 68 patients and 70 renal units underwent microperc procedure. The mean age of the patients was 41.4 ± 18.8. The mean BMI was 26.3 ± 5.5 kg/m2, and the Karatag/Buldu/Inan/Istanbulluoglu
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Materials and Methods
Characteristics
Value (mean ± SD)
Number Patient age, years Male/Female Laterality, right/left BMI, kg/m2 Stone size, mm Stone opacity, opaque/ semi-nonopaque Stone localization Pelvis Lower calyx Middle calyx Upper calyx
68 41.4±18.8 (2–86) 39/29 34/36 28.6±6.0 (13.2–39.0) 122±83 mm2 (27–450)
ble pain after the removal of ureteric catheters postoperatively. The stents of these three patients were removed after four weeks. Any pain or hydronephrosis did not occur. The peri-operative results are listed in table 2.
Discussion
mean stone size was 122 ± 83 mm2. The characteristics of patients are listed in table 1. The operations were performed under spinal anesthesia in 89.7% of the patients. Stone-free rate was 95.7 % (67/70). Clinically significant residual fragments were observed in three patients. The average duration of operation and mean fluoroscopy time was 40 ± 23 min and 108 ± 72 s, respectively. The mean postoperative drop in hemoglobin was 0.95 ± 0.7 while no patient required blood transfusion. The patients were discharged after an average hospitalization time of 27.5 ± 12.4 hours. A total of 4 complications (5.7%), including urinary tract infection (Clavien I) in one patient and renal colics requiring stent insertion (Clavien IIIa) in three patients, were observed postoperatively. Urinary tract infection was treated with appropriate antibiotics. Three patients underwent JJ stent insertion due to the development of hydronephrosis and intracta-
Urolithiasis is a common disease with globally increasing incidence and significant socioeconomic implications [8, 9]. Since the entry of percutaneous nephrolithotomy into the world of endourology in 1976, it has become an optional management for the treatment of renal stones. Over the years, many researchers have carried out many advancements in the technique and instrumentation in order to determine appropriate management with the highest stone-free and lowest morbidity rate for the treatment of renal stones [10]. Although standard PNL has been recently accepted for large burden renal stones, the main discussions have been maintained for the moderate-sized renal calculi [11]. Many kinds of treatment modalities such as SWL, RIRS, and PNL ranging from noninvasive to invasive have been suggested for those moderate-sized renal calculi. Microperc technique is also an option with the important refinements based on improvements in the optical and puncture system. However, optimal treatment can be changed according to the size and the location of the stone and characteristics of the patient. SWL has been accepted as first-line treatment modality for renal calculi till 2cm in diameter [12]; however, some limitations, including lower calyx location, composition, and steep infundibulo-pelvic angle, have been suggested for affecting the stone-free rates [13]. Patient-related factors such as obesity or severe skeletal malformations may also affect the success rates. Moreover, another drawback of SWL is the need to have relatively multiple sessions. Indeed, the size and compositions of the stones are considerable for this fact. On the other hand, the noninvasive nature of SWL makes it favorable for the patients who have concerns for surgery. Various studies concluded that successes of SWL are inversely correlated with stone size [14]. However, in the study of 438 patients, Khalil et al. stated that stone burden rather than stone location was a more important predictor of the outcome of SWL. He found the SFR for stones in the renal pelvis, lower, middle, and upper calices as 72.4, 56, 55.6, and 69%, respectively, whereas those for stones that were 1 cm, 1.1 to 2 cm, and >2 cm were 50.2, 39.6, and 10.2% [15].
Microperc for Moderate-Sized Kidney Stones
Urol Int DOI: 10.1159/000368373
62/8 19 27 9 4
Table 2. Postoperative results of procedures
Characteristics
Value (mean ± SD)
Operation time, min Fluoroscopy time, seconds Hospitalization, h Hemoglobin drop, g/dl Success, % Stone free Complications, n (%) Urinary tract infection (Clavien I) Renal colic requiring D-J stent insertion (Clavien III)
40.6±23.8 (10–150) 108.4±72.6 (30–300) 27.5±12.4 (15–60) 0.95±0.7 (0.1–1.5) 95.7 (67/70) 4 (5.7) 1 3
3
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Table 1. The demographic values of the patients are listed
4
Urol Int DOI: 10.1159/000368373
ifices, it also does not appear to be affected by body habitus. On the other hand, the main drawbacks of RIRS are ureteric stent requirement for many patients postoperatively and need to have multiple sessions for a satisfactory stone clearance [24, 25]. Retrieval devices and basket catheters are frequently used in RIRS procedures; thus, microperc surgery seems to be more cost effective in the comparison with RIRS. However, no comparative study focusing on this issue is available yet. Recently, Sabnis et al. published the only comparative results of RIRS and microperc surgery for small renal stones in a randomized control trial. The author reported similar stone clearance rate and complication rate but mentioned higher analgesic requirements for microperc and a higher requirement for JJ stenting for RIRS [23]. Jackman et al defined the ‘mini-perc’ as a PNL modality achieved through an 11-Fr peel-away vascular access sheath to accommodate a standard rigid nephroscope in seven infants and preschool age children [26]. Miniperc is a multistep procedure similar to standard PNL, except for the smaller tract size. However, micro-PNL is a singlestep renal access with fragmentation procedure. Therefore, complications related to tract size and multiple steps in miniperc can be expected to be higher in contrast to micro-PNL. Nevertheless, no studies comparing these procedures are available yet. Another advantage of miniperc is the ability of retrieval of the fragments. Regarding situations mentioned earlier, we may consider miniperc for larger renal stones than preferred for micro-PNL. Although the advantages of mini-PNL in adults remain controversial, EAU-guidelines recommend the mini-PNL as a first-line therapy for percutaneous stone removal in children. Furthermore, microperc might be potentially advantageous in the pediatric age group. Recently, Silay et al. reported a stone-free rate of 89.5% and only one complication managed with percutaneous drainage intraoperatively in 19 pediatric patients [27]. In our clinical series, we also observed no complication in 8 pediatric patients, as the youngest one was one year old. RIRS may pose a risk of ureteric damage for pediatric population. In a pediatric series of 170 patient undergoing RIRS procedures, passive dilatation of the ureter was required for 57% of the patients for 1–2 weeks before the ureteroscope could be inserted into the ureter [28]. However, microperc surgery does not carry a risk of ureteric injury relatively. Regarding recent guidelines, EAU does not recommend RIRS as a first-line therapy, especially for renal stones >1.5 cm due to lower stone-free rates and often requiring staged procedures [17]. Karatag/Buldu/Inan/Istanbulluoglu
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
According to results of such studies, it may be considered that many patients needed to have additional therapy. Here, we should mention that our stone-free rate with microperc nephrolithotomy was 95.7% for moderatesized renal calculi and all procedures were performed only in a single session. Other factors, including stone composition and body mass index (BMI), may also influence the success rates of SWL and micro-PNL [16, 17]. Although some patients’ information was not available (27.6%), the distribution of stone component was as follows: Calcium oxalate monohydrate 47.3%, uric acid 12.4%, calcium phosphate 16.6%, struvite 9.4%, calcium oxalate dihydrate 6.3%, and cystine 8%. Several studies demonstrated that calcium oxalate monohydrate, brushite, and cysteine stones were more resistant to SWL than the others [18, 19]. Pareek et al. indicated that BMI independently predicted the SWL results and reported that patients with a BMI ≥30 kg/m2 would be more suitable for endoscopic surgery. He also mentioned that SSD of 12 cm was an independent predictor of unfavorable outcomes, suggesting that SSD might more accurately link obesity with SWL failure [20]. Regarding the superiorities of microperc to SWL, we may consider that stone disintegration is performed using laser under direct vision. The stone fragmentation can be performed in different settings to achieve dusting or fragments in size of 1–2 mm according to stone disintegration. Moreover, saline irrigation aids the removal of the stone debris during the surgery and provides the flush out of the stone fragments and dust particles through the ureteral catheter continuously. In our study, 12 patients had a history of failure of SWL and all of them had stonefree status postoperatively. Recently, the only comparison of SWL and microperc procedure has been reported for the pediatric population. Hatipoglu et al found a similar stone-free rate and lower additional treatment in their series [21]. On the other hand, the recent guidelines of the European Association of Urology (EAU) recommend SWL for stones till 2 cm in all intrarenal locations, except for the lower pole [17]. For the lower pole stones of 10 mm), narrow infundibulum (
Urologia
Received: May 8, 2014 Accepted after revision: September 16, 2014 Published online: February 17, 2015
Urol Int DOI: 10.1159/000368373
Internationalis
Is Micropercutaneous Nephrolithotomy Technique Really Efficacicous for the Treatment of Moderate Size Renal Calculi? Yes Tuna Karatag Ibrahim Buldu Ramazan Inan Mustafa Okan Istanbulluoglu Mevlana University, Konya, Turkey
Key Words Micropercutaneous nephrolithotomy · Safety · Feasibility
rolithotomy should be considered for the treatment of moderate-sized renal stones as an alternative to SWL and RIRS failures and also may be considered even primarily. © 2015 S. Karger AG, Basel
© 2015 S. Karger AG, Basel 0042–1138/15/0000–0000$39.50/0 E-Mail [email protected] www.karger.com/uin
Introduction
Since its introduction in 1976, percutaneous nephrolithotomy (PNL) has developed considerably as a result of technological refinements and surgical experiences to minimize postoperative pain, morbidity, and hospitalization [1]. Although many kinds of treatment modalities such as SWL, RIRS, and PNL ranging from noninvasive to invasive have been suggested for the moderate-sized renal calculi, optimal treatment can be changed according to the size and the location of stones and characteristics of the patient. After introduction of optic puncture system in renal stone treatment in 2011 [2], micro-percutaneuos nephrolithotomy procedures have become a choice for the treatment of moderate-sized kidney stones with the advantages of providing single-step percutaneous renal access under direct vision through a 4.8 SFR sheath. Although some data, including comparative results, in order to determine the appropriate management with highest stone-free and less morbidity rate are available, the initial reports have suggested that micro-percuTuna Karatag, MD Department of Urology, Faculty of Medicine Mevlana University TR–42200 Konya (Turkey) E-Mail tunakaratag @ gmail.com
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Abstract Objective: To present our clinical experiences with micropercutaneous nephrolithotomy in the treatment of moderatesized renal calculi from a single center. Methods: We retrospectively evaluated the patients with moderate-sized renal calculi who underwent micro-percutaneous nephrolithotomy between December 2012 and Septermber 2013. Results: A total of 68 patients and 70 renal units underwent microperc procedure. Mean age of patients was 41.4 ± 18.8. The mean stone size was 122 ± 83 mm2. The operations were performed under spinal anesthesia in 89.7% of the patients. Stone-free rate was 95.7 % (67/70). Clinically significant residual fragments were observed in three patients. The average duration of operation and mean fluoroscopy time was 40 ± 23 min and 108 ± 72 s, respectively. The mean postoperative drop in hemoglobin was 0.95 ± 0.7 while no patient required blood transfusion. Patients were discharged after an average hospitalization time of 27.5 ± 12.4 h. A total of 4 complications (5.7%), including urinary tract infection (Clavien I) in one patient and renal colics requiring stent insertion (Clavien IIIa) in three patients, were observed postoperatively. Conclusion: Microperc technique is safe, feasible, and efficacious. We suggest that micro-percutaneous neph-
Color version available online
Color version available online
Fig. 1. Microperc system with a three-channel connector.
Fig. 2. Dust particle removal out of 7 SFR urethral catheter.
taneous nephrolithotomy technique was feasible, safe, and efficacious for the small and moderate-sized kidney stones [3–5]. In this study, we present our clinical experiences of microperc surgery for the treatment of the moderate-sized renal calculi, commonly performed under spinal anesthesia as distinct from other reports.
puncture. Percutaneous renal access to the caliceal fornix was achieved using a 16-gauge needle with the C-arm fluoroscopy guidance; inner and outer puncture shafts of the 4.8 SFR ‘allseeing needle’ microperc system (PolyDiagnost, Pfaffenhofen, Germany) were placed and after taking out the inner shaft, a three-way connector allowing the insertion of a 0.9-mm flexible micro-optic, laser fiber, and irrigation system was attached to the outer tip of the shaft (fig. 1). Usually, the stone containing calyx was targeted; if the stone was in the renal pelvis, either middle or lower calyceal puncture was preferred. The stone fragmentation was usually achieved using a 200-μm holmium: YAG laser fiber in the settings of 0.2 J at 50 Hz. Irrigation was carried out using a mechanical pump with foot pedal control. Saline irrigation aids the maintenance of proper vision and removal of the stone debris during the surgery and provides the flush out of the stone fragments and dust particles through the ureteral catheter continuously (fig. 2). Intermittent manual suction also can be done through the ureteric catheter to reduce the intrarenal pressure. We did not put any nephrostomy catheter while the ureteric catheter was left in place postoperatively. The patients were routinely discharged after removal of the urethral and ureteral catheter on the first postoperative day if there was no complication. All of the patients underwent a radiological assessment with KUB on the first postoperative day. Success was defined as a non-residual fragment on X-ray KUB images of the first month of follow-up. Clinically insignificant residual fragments (CIRF) were defined as asymptomatic fragments ≤4 mm [6]. The postoperative complications were evaluated using Clavien grading system [7].
We retrospectively reviewed the patients with moderatedsized renal calculi who underwent microperc nephrolithotomy procedure in our clinic between December 2012 and September 2013. Our series consisted of the patients with a history of failed SWL and RIRS treatment and the patients with moderate-sized stones larger than 1 cm primarily according to the patient preference. We excluded the patients who underwent standard PNL for the opposite renal stone at the same time. The patients’ characteristics were enrolled in terms of age, BMI, blood parameters, stone burden, and related parameters. Informed consent form was obtained from each patient before surgery. Radiological evaluation was performed with computed tomography for all patients. The patients with positive urine cultures were also treated with appropriate antibiotics preoperatively. Technique of Microperc Procedure Although the procedure can be carried out under general anesthesia if required, we commonly performed our procedures under regional anesthesia. A 7 SFR ureteric catheter was inserted through the ureter into the renal pelvis under cystoscopic and fluoroscopic guidance in the lithotomy position. Then, the patient was turned to the prone position after fixing the ureteric catheter to the urethral catheter. The pelvicalyceal system was filled with diluted contrast agent injected retrograde through the ureteric catheter. This creates a mild hydronephrosis and demonstrates the configuration of pelvicalyceal system, which aids calyceal
2
Urol Int DOI: 10.1159/000368373
Results
A total of 68 patients and 70 renal units underwent microperc procedure. The mean age of the patients was 41.4 ± 18.8. The mean BMI was 26.3 ± 5.5 kg/m2, and the Karatag/Buldu/Inan/Istanbulluoglu
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Materials and Methods
Characteristics
Value (mean ± SD)
Number Patient age, years Male/Female Laterality, right/left BMI, kg/m2 Stone size, mm Stone opacity, opaque/ semi-nonopaque Stone localization Pelvis Lower calyx Middle calyx Upper calyx
68 41.4±18.8 (2–86) 39/29 34/36 28.6±6.0 (13.2–39.0) 122±83 mm2 (27–450)
ble pain after the removal of ureteric catheters postoperatively. The stents of these three patients were removed after four weeks. Any pain or hydronephrosis did not occur. The peri-operative results are listed in table 2.
Discussion
mean stone size was 122 ± 83 mm2. The characteristics of patients are listed in table 1. The operations were performed under spinal anesthesia in 89.7% of the patients. Stone-free rate was 95.7 % (67/70). Clinically significant residual fragments were observed in three patients. The average duration of operation and mean fluoroscopy time was 40 ± 23 min and 108 ± 72 s, respectively. The mean postoperative drop in hemoglobin was 0.95 ± 0.7 while no patient required blood transfusion. The patients were discharged after an average hospitalization time of 27.5 ± 12.4 hours. A total of 4 complications (5.7%), including urinary tract infection (Clavien I) in one patient and renal colics requiring stent insertion (Clavien IIIa) in three patients, were observed postoperatively. Urinary tract infection was treated with appropriate antibiotics. Three patients underwent JJ stent insertion due to the development of hydronephrosis and intracta-
Urolithiasis is a common disease with globally increasing incidence and significant socioeconomic implications [8, 9]. Since the entry of percutaneous nephrolithotomy into the world of endourology in 1976, it has become an optional management for the treatment of renal stones. Over the years, many researchers have carried out many advancements in the technique and instrumentation in order to determine appropriate management with the highest stone-free and lowest morbidity rate for the treatment of renal stones [10]. Although standard PNL has been recently accepted for large burden renal stones, the main discussions have been maintained for the moderate-sized renal calculi [11]. Many kinds of treatment modalities such as SWL, RIRS, and PNL ranging from noninvasive to invasive have been suggested for those moderate-sized renal calculi. Microperc technique is also an option with the important refinements based on improvements in the optical and puncture system. However, optimal treatment can be changed according to the size and the location of the stone and characteristics of the patient. SWL has been accepted as first-line treatment modality for renal calculi till 2cm in diameter [12]; however, some limitations, including lower calyx location, composition, and steep infundibulo-pelvic angle, have been suggested for affecting the stone-free rates [13]. Patient-related factors such as obesity or severe skeletal malformations may also affect the success rates. Moreover, another drawback of SWL is the need to have relatively multiple sessions. Indeed, the size and compositions of the stones are considerable for this fact. On the other hand, the noninvasive nature of SWL makes it favorable for the patients who have concerns for surgery. Various studies concluded that successes of SWL are inversely correlated with stone size [14]. However, in the study of 438 patients, Khalil et al. stated that stone burden rather than stone location was a more important predictor of the outcome of SWL. He found the SFR for stones in the renal pelvis, lower, middle, and upper calices as 72.4, 56, 55.6, and 69%, respectively, whereas those for stones that were 1 cm, 1.1 to 2 cm, and >2 cm were 50.2, 39.6, and 10.2% [15].
Microperc for Moderate-Sized Kidney Stones
Urol Int DOI: 10.1159/000368373
62/8 19 27 9 4
Table 2. Postoperative results of procedures
Characteristics
Value (mean ± SD)
Operation time, min Fluoroscopy time, seconds Hospitalization, h Hemoglobin drop, g/dl Success, % Stone free Complications, n (%) Urinary tract infection (Clavien I) Renal colic requiring D-J stent insertion (Clavien III)
40.6±23.8 (10–150) 108.4±72.6 (30–300) 27.5±12.4 (15–60) 0.95±0.7 (0.1–1.5) 95.7 (67/70) 4 (5.7) 1 3
3
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
Table 1. The demographic values of the patients are listed
4
Urol Int DOI: 10.1159/000368373
ifices, it also does not appear to be affected by body habitus. On the other hand, the main drawbacks of RIRS are ureteric stent requirement for many patients postoperatively and need to have multiple sessions for a satisfactory stone clearance [24, 25]. Retrieval devices and basket catheters are frequently used in RIRS procedures; thus, microperc surgery seems to be more cost effective in the comparison with RIRS. However, no comparative study focusing on this issue is available yet. Recently, Sabnis et al. published the only comparative results of RIRS and microperc surgery for small renal stones in a randomized control trial. The author reported similar stone clearance rate and complication rate but mentioned higher analgesic requirements for microperc and a higher requirement for JJ stenting for RIRS [23]. Jackman et al defined the ‘mini-perc’ as a PNL modality achieved through an 11-Fr peel-away vascular access sheath to accommodate a standard rigid nephroscope in seven infants and preschool age children [26]. Miniperc is a multistep procedure similar to standard PNL, except for the smaller tract size. However, micro-PNL is a singlestep renal access with fragmentation procedure. Therefore, complications related to tract size and multiple steps in miniperc can be expected to be higher in contrast to micro-PNL. Nevertheless, no studies comparing these procedures are available yet. Another advantage of miniperc is the ability of retrieval of the fragments. Regarding situations mentioned earlier, we may consider miniperc for larger renal stones than preferred for micro-PNL. Although the advantages of mini-PNL in adults remain controversial, EAU-guidelines recommend the mini-PNL as a first-line therapy for percutaneous stone removal in children. Furthermore, microperc might be potentially advantageous in the pediatric age group. Recently, Silay et al. reported a stone-free rate of 89.5% and only one complication managed with percutaneous drainage intraoperatively in 19 pediatric patients [27]. In our clinical series, we also observed no complication in 8 pediatric patients, as the youngest one was one year old. RIRS may pose a risk of ureteric damage for pediatric population. In a pediatric series of 170 patient undergoing RIRS procedures, passive dilatation of the ureter was required for 57% of the patients for 1–2 weeks before the ureteroscope could be inserted into the ureter [28]. However, microperc surgery does not carry a risk of ureteric injury relatively. Regarding recent guidelines, EAU does not recommend RIRS as a first-line therapy, especially for renal stones >1.5 cm due to lower stone-free rates and often requiring staged procedures [17]. Karatag/Buldu/Inan/Istanbulluoglu
Downloaded by: James Cook University 137.219.5.13 - 3/15/2015 10:15:21 PM
According to results of such studies, it may be considered that many patients needed to have additional therapy. Here, we should mention that our stone-free rate with microperc nephrolithotomy was 95.7% for moderatesized renal calculi and all procedures were performed only in a single session. Other factors, including stone composition and body mass index (BMI), may also influence the success rates of SWL and micro-PNL [16, 17]. Although some patients’ information was not available (27.6%), the distribution of stone component was as follows: Calcium oxalate monohydrate 47.3%, uric acid 12.4%, calcium phosphate 16.6%, struvite 9.4%, calcium oxalate dihydrate 6.3%, and cystine 8%. Several studies demonstrated that calcium oxalate monohydrate, brushite, and cysteine stones were more resistant to SWL than the others [18, 19]. Pareek et al. indicated that BMI independently predicted the SWL results and reported that patients with a BMI ≥30 kg/m2 would be more suitable for endoscopic surgery. He also mentioned that SSD of 12 cm was an independent predictor of unfavorable outcomes, suggesting that SSD might more accurately link obesity with SWL failure [20]. Regarding the superiorities of microperc to SWL, we may consider that stone disintegration is performed using laser under direct vision. The stone fragmentation can be performed in different settings to achieve dusting or fragments in size of 1–2 mm according to stone disintegration. Moreover, saline irrigation aids the removal of the stone debris during the surgery and provides the flush out of the stone fragments and dust particles through the ureteral catheter continuously. In our study, 12 patients had a history of failure of SWL and all of them had stonefree status postoperatively. Recently, the only comparison of SWL and microperc procedure has been reported for the pediatric population. Hatipoglu et al found a similar stone-free rate and lower additional treatment in their series [21]. On the other hand, the recent guidelines of the European Association of Urology (EAU) recommend SWL for stones till 2 cm in all intrarenal locations, except for the lower pole [17]. For the lower pole stones of 10 mm), narrow infundibulum (
