Scandinavian Journal of Urology. 2014; 48: 295–300

ORIGINAL ARTICLE

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Combination of debulking single-tract percutaneous nephrolithotomy followed by retrograde intrarenal surgery for staghorn stones in solitary kidneys

GUOHUA ZENG*, ZHIJIAN ZHAO*, WENQI WU & WEN ZHONG Department of Urology, Minimally Invasive Surgery Center, First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, Guangzhou, PR China

Abstract Objective. The aim of this study was to report a therapeutic approach comprising a combination of debulking single-tract percutaneous nephrolithotomy (PCNL) and subsequent retrograde intrarenal surgery (RIRS) for treatment of staghorn stones in patients with solitary kidney. Materials and methods. A retrospective review was undertaken of 56 patients with staghorn stones in a solitary kidney who underwent the above-mentioned combination therapy. PCNL was first performed for stone debulking and RIRS was then used to remove residual stones after an interval of 2–4 days. Data were collected on operative parameters, stone-free rate (SFR), complications and renal functions. Results. The staghorn stones had a mean stone burden of 2548 ± 1028 mm2 (range 1438–3956 mm2). The SFR after 3 months was 89.3%. The overall blood transfusion rate was 7.1%. Complications were observed in nine patients (16.1%), including selective renal artery embolization, fever, gross haematuria and steinstrasse in one, two, three and three cases, respectively. At a mean follow-up of 31 months, available in 38 patients, kidney function was stable in 71%, improved in 26.3% and worsened in 2.7%, according to serum creatinine levels that remained within ±20%, or that increased or decreased outside this range. No patient required haemodialysis. Conclusions. Combining single-tract PCNL with subsequent RIRS was an effective strategic option for treating staghorn stones in solitary kidneys. The method gave an excellent SFR, satisfactory preservation of renal function, reduced bleeding risk and potentially less morbidity than that associated with multiple-tract PCNL.

Key Words: percutaneous nephrolithotomy, retrograde intrarenal surgery, solitary kidney, staghorn stone

Introduction An untreated staghorn stone is likely to destroy kidney function, a situation that is particularly problematic for patients with a solitary kidney [1]. Although percutaneous nephrolithotomy (PCNL) currently is the gold standard for treatment of staghorn stones, the debate continues on the use of single-tract versus multiple-tract PCNL in these cases [1,2]. Access to all of the calyces through one percutaneous tract may be difficult owing to the peculiar anatomical structure of the collecting system. Nevertheless, in solitary kidneys with large stone burdens, branched stones, satellite stones or

residual stones in parallel calyces, multiple access tracts during PCNL are often required. However, as the number of tracts increases, blood loss and renal parenchymal injury can increase [3,4]. It is also noteworthy that in patients with a solitary kidney, removal of the staghorn stones is not the only goal, and the preservation of kidney function and reduction of massive bleeding are crucial aims, because these patients have a higher stone recurrence rate and a higher incidence of acute renal failure (ARF), and are more prone to bleeding than those with two kidneys [5]. Many surgeons were reluctant to use extracorporeal shockwave lithotripsy (ESWL)

Correspondence: G. Zeng, Department of Urology, Minimally Invasive Surgery Center, First Affiliated Hospital of Guangzhou Medical University, Guangdong Key Laboratory of Urology, 1# Kangda Road, Haizhu District, Guangzhou 510230, PR China. E-mail: [email protected] * These authors contributed equally to this work.

(Received 25 April 2013; revised 22 September 2013; accepted 1 October 2013) ISSN 2168-1805 print/ISSN 2168-1813 online  2014 Informa Healthcare DOI: 10.3109/21681805.2013.852621

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Table I. Outcome of single-tract percutaneous nephrolithotomy (PCNL) for staghorn stone debulking. Median operative time (min)

108 ± 16 (74–145)

No. of blood transfusions

3 (5.3)

No. of complications

6 (10.7)

Haemoglobin drop (g/l) Mean no. of residual stones

13.1 ± 6.8 (4–48) 1.9 ± 0.9 (1–4)

Stone location after PCNL Upper + lower calyx

24 (42.8)

Lower calyx

22 (39.3)

Middle + upper calyx

10 (17.9)

Data are shown as mean ± SD (range) or n (%).

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culture, coagulation studies, and measurement of serum creatinine (SCr) and haemoglobin. In addition to plain abdominal film, intravenous urogram (IVU) and/or non-contrast computed tomography (CT) evaluations were performed in all cases preoperatively (Figure 1 A–D). Positive urine cultures and febrile urinary infection were adequately treated with appropriate antibiotics.

in cases of solitary kidney because of the greater risk of obstruction by stone fragments, with subsequent anuria and the potential risk of long-term deterioration of renal function [6,7]. Retrograde intrarenal surgery (RIRS) allows retrograde access to the entire intrarenal collecting system when treating renal calculi with the aim of achieving a completely stone-free kidney, and RIRS is safer than PCNL. However, RIRS is burdened with high rates of fibre breakage and lower efficiency for removal of larger stones [8]. Although it is less ideal for management of the whole staghorn stone, RIRS can be used as an auxiliary procedure to PCNL in order to reach peripherally located renal residual calculi to achieve a stone-free kidney while maintaining maximum renal function. The present study reports the authors’ experience with the combination of debulking single-tract PCNL and subsequent RIRS for the treatment of staghorn stones in patients with solitary kidney. The efficacy and advantages of the treatment strategy are assessed. Material and methods Between January 2008 and May 2012, 102 consecutive patients with staghorn stones in solitary kidneys underwent a planned single-tract PCNL. In each patient fluoroscopic imaging and/or flexible nephroscopy were used to find and disintegrate residual stones as extensively as possible at the end of the first PCNL procedure. However, it was not always possible to reach every residual stone with the flexible nephroscope, especially when the stone was located in a neighbouring calix parallel to PCNL tract. Of the 102 patients, 29 patients became stone free and 17 were reluctant to receive RIRS after a session of single-tract PCNL. The remaining 56 patients who were treated with single-tract PCNL followed by RIRS, carried out by a single surgeon, were included in this retrospective study. Patient assessment included presenting symptoms, physical examination, routine complete blood count, urinalysis, urine

Operative procedures In all patients PCNL was carried out through a single 18 Fr tract under fluoroscopic guidance. Because of the staghorn morphology of the stones, the single access was attempted where the greatest stone burden could be cleared and the selection was based on stone configuration. An 8/9.8 Fr semi-rigid ureteroscope, 18 Fr access sheath and pulsatile low-pressure perfusion pump were used for minimally invasive PCNL in the prone position. (The addition of the pulsatile perfusion pump reduced the frequency of using grasping forceps and stone baskets and could shorten the operating time.) A detailed description of this procedure has been published previously [9]. In cases where the procedure was performed in stages, the puncturing nephrostomy tube was left in place. The subsequent minimally invasive PCNL procedure was performed through the same but now matured tract. Fluoroscopy was again used at the end of the procedure for detection of residual calculi. If fragments were found that could not be accessed with the rigid nephroscope, a flexible nephroscope was used to remove residual fragments as extensively as possible. Finally, a 5 Fr double-J stent and a same-calibre silastic 18 Fr nephrostomy tube were placed under direct vision. Residual fragments after PCNL were assessed using plain films of kidney–ureter–bladder (KUB) 1 or 2 days postoperatively (Figure 1E). The second stage RIRS procedure was carried out after an interval of 2–4 days following PCNL, when the drainage of the nephrostomy tube was free of gross blood. If the patient underwent selective renal artery embolization after PCNL, RIRS was postponed for at least 30 days. For the RIRS procedures, the patient was placed in the lithotomy position and a flexible 0.035-inch Zebra guidewire (Boston Scientific Corporation) was routinely inserted before the double-J stent was removed. A 12 Fr/14 Fr Flexor ureteral access sheath (Cook Urological, USA) was advanced into the proximal ureter over the guidewire. Next, a 7.5 Fr flexible ureteroscope (Olympus, Japan) was inserted through the access sheath. The renal stones and collecting system were carefully inspected. Residual stones in the peripheral calyces, which would have required a

Treatment of staghorn stones in solitary kidneys

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A

B

C

E

297

D

F

Figure 1. Combination of debulking single-tract percutaneous nephrolithotomy (PCNL) and subsequent retrograde intrarenal surgery (RIRS) for staghorn stones in a 55-year-old man with a glomerular filtration rate of 5.6 ml/min in the atrophic left kidney: (A) kidney–ureter–bladder (KUB) image before operation; (B) transverse computed tomography (CT) image; (C) longitudinal CT image; (D) three-dimensional CT image; (E) KUB after PCNL procedure, day 2; (F) KUB after RIRS procedure, 2 weeks.

second or third nephrostomy access, were fragmented with a 200 mm holmium laser fibre and 8–20 W of energy. A 5 Fr double-J ureteral stent was placed at the conclusion of the procedure. After another day, a repeat KUB was performed. If that examination did not show any significant residual stones, the patient

was discharged 2 days after the RIRS procedures, following removal of the nephrostomy tube. The ureteral stent was removed 2 weeks later, during an outpatient visit. SCr was measured postoperatively after 2 weeks and after more than 1 year in as many patients as possible.

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Table II. Outcome of retrograde intrarenal surgery (RIRS) for residual stones. Mean operative time (min) Haemoglobin drop (g/l)

73 ± 19 (36–124) 9.0 ± 4.9 (0–18)

Blood transfusion

0

No. of complications

3 (5.4)

Final stone-free rate

50/56 (89.3)

Overall hospital stay of two procedures (days)

9 ± 3.3 (6–15)

Data are shown as mean ± SD (range) or n (%).

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Statistical analysis and outcome measures The stone surface area was calculated by measuring the length of the stone on radiological imaging in the left–right and cephalad–caudal planes, and multiplying the two values together. If multiple stones were present, the area of each stone was added together to determine the total stone area. The stone-free rate (SFR) was defined as no residual fragments or residual fragments smaller than 2 mm detected with noncontrast CT or KUB at the 2-week follow-up when the patients returned to the hospital for stent removal (Figure 1F). Perioperative complications of all patients were recorded according to the modified Clavien classification system [10]. Renal function was assessed after 2 weeks and after 1 year by analysis of SCr. Improvement in the renal function was defined as a 20% decrease from the baseline value and deterioration as a 20% increase above baseline, while values within 20% of the baseline level were considered stable [11]. Patients’ demographics, operative parameters, SFRs, complications and renal functions were evaluated. The changes in SCr were compared between those with struvite stones and those with other stone compositions. All statistical analyses were performed using SPSS 13.0 or Microsoft Excel.

Results In total, 56 PCNL procedures were performed in 56 patients with solitary kidneys. The mean (± SD) age of the patients was 44.4 ± 13.3 years (range 19– 76 years) and the male to female ratio was 1.3:1. The staghorn stones had a mean stone burden of 2548 ± 1128 mm2 (range 1438–3956 mm2). The aetiology of the solitary kidney was contralateral nephrectomy in 24 cases (42.8%), atrophic and non-perfused kidneys in 29 (51.8%) and congenital solitary kidneys in three (5.4%). Of the 56 single-tract PCNL procedures, the numbers of punctures through the upper, middle and lower poles were 12 (21.4%), 35 (62.5%) and nine (16.1%), respectively. Complications were

observed in six patients after PCNL (10.7%) (Table I). One patient experienced bleeding (grade IIIa) with a haemoglobin drop of 48 g/l. He required blood transfusions and selective renal arterial embolization and the RIRS procedure was postponed for 30 days after PCNL. Two patients had fever higher than 38.5 C during more than 2 days necessitating additional antibiotics (grade II). Gross haematuria occurred in three cases, two of whom needed blood transfusion (grade II), while another patient stopped bleeding spontaneously (grade I). All locations of residual stones are detailed in Table II. The mean number of residual stones was 1.9 ± 0.9 (1–4). The burden of the largest residual stones was 1289 mm2. Stone composition were evaluated in all cases: the percentages of stones composed of calcium oxalate, magnesium ammonium phosphate, uric acid, carbapatite and cystin were 53.6%, 26.7%, 7.2%, 10.7% and 1.8%, respectively. Thirty-seven patients had a 24 h urine analysis before surgery, with a 64.9% rate (24/37) of any metabolic abnormality. Hypercalciuiria was recorded in 14 patients (37.8%), hyperoxaluria in 12 (32.4%), hyperuricosuria in nine (24.3%) and hypocitratuiria in 13 (35.1%). For the RIRS procedure, the overall SFR was 89.3% (50/56) (Table II). At the 2 week follow-up, residual stone fragments were detected in six patients (10.7%). Three of them were retreated with miniPCNL because one patient had lower calyceal residual stones and an acute infundibulopelvic angle. In two patients the residuals were not detected during RIRS. Two patients underwent a second RIRS procedure and conservative observation was planned for one patient with small residual stones. Fever accompanying steinstrasse occurred in three patients, who were managed with rigid ureteroscopy (grade IIIa). None of them required blood transfusion. The overall hospital stay required for the two procedures was 9 ± 3.3 days (6–15 days). At the 2 week short-term follow-up, according to the definition above, kidney function was stable, improved and worsened in 39 (69.6%), 14 (25%) and three patients (5.4%, respectively. SCr levels for the whole group had decreased from 165.3 mol/ l (range 99–310 mol/l) (preoperatively) to 148.7 mol/l (88–230 mol/l) (p < 0.0001). In those patients in whom SCr analyses were available more than 2 months from their last RIRS procedure (n = 38), renal function was considered stable at 163.3 mol/l (preoperatively) and 146.2 mol/l (n = 27), and deteriorated from 167.3 to 211.6 mol/l in one patient. No patient required haemodialysis. The mean duration of follow-up with regard to renal function was 31.7 months (range 12–62 months).

Treatment of staghorn stones in solitary kidneys

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Discussion Multiple-tract access can address the primary objective of achieving the highest SFRs. The SFRs via multiple tracts in some studies were greater than 71% after a single session and increased to above 90% after a second look procedure [4,12]. However, the use of large-size sheaths and multiple tracts has been reported to result in more blood loss and subsequently increased transfusion rates, which could be up to 46% [3,4,12]. As reported by a global PCNL study for solitary kidneys, bleeding and the need for blood transfusions were more than doubled in solitary kidneys compared with the rates recorded in patients with two kidneys. There was also a significant rise in serum creatinine in the former group [5]. El-Nahas et al. [13] demonstrated that the presence of solitary kidney was a significant risk factor for haemorrhage during puncture and dilatation because of the compensatory hypertrophy of the remaining renal parenchyma and renal vessel. Therefore, avoiding multi-tract PCNL seems to be the most important factor in reducing complications and protecting renal function in patients with solitary kidneys [14]. In many centres surgeons were reluctant to use ESWL for solitary kidneys owing to the relatively low SFR in treating large stones, the greater risk of obstruction with stone fragments and subsequent anuria with the risk of long-term deterioration of renal function [6,7]. Chandhoke et al. reported that patients with creatinine greater than 3 mg/dl undergoing ESWL had short-term improvement but eventually long-term deterioration in renal function [6]. El-Assmy et al. reported that 27.7% of ESWL-treated patients with solitary kidney had increasing serum creatinine values after 12 months [7]. Recently, a few reports have demonstrated the favourable use of flexible instruments to gain intrarenal access and thus reduce the number of PCNL tracts [15,16]. Marguet et al. [15] first used retrograde ureteroscopy to clear stones in the peripheral calices. Patients were then placed in the prone position and single-access PCNL was performed. This manoeuvre reduced the number of percutaneous access tracts, potential patient morbidities and blood loss, with no significant effect on SFRs or operative time [15]. Hoznek et al. presented patients treated in the Galdakao-modified supine Valdivia (GMSV) position for PCNL. This allowed treatment with both antegrade and retrograde access during the same procedure. It also improved anaesthetic delivery, increased patient safety and reduced operating time [16]. However, this approach may also increase the risks of complications for patients with solitary

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kidneys. Moreover, two experienced stone surgeons were required for the procedure. In the present study, the intrarenal blind zone during PCNL could often be visualized during RIRS. When PCNL and RIRS are used together, they are complementary to each other and it is thus possible to achieve the highest SFRs by establishing the lowest number of percutaneous tracts. The SFR increased to 89.3% after the combined procedures. In addition, minimal morbidity occurred in this group of patients. In these patients only 7.1% required blood transfusion and 16.1% had complications. In another study there was a 28.7% complication rate in patients with solitary kidneys, including 10.1% with bleeding and 13.3% with fever [5]. It is worthwhile to evaluate the short- and long-term effects on renal function. At present, there are no available well-designed trials comparing the longterm renal effects of multiple-tract PCNL and single-tract PCNL. Akman et al. [12] reported 28.4% transfusion after multiple-tract PCNL and 13.9% after single tract PCNL procedures, but their impact on renal function was similar. However, Desai et al. [15] reported that there was a significant rise in serum creatinine and drop in creatinine clearance in the multiple-tract group. Handa et al. [17] also reported that dilatation of multiple tracts showed an acute decline in renal function compared with that in single-tract procedures. Akman et al. [18] used multivariate analysis to reveal that an immediate postoperative change in the estimated glomerular filtration rate was the only factor predicting the long-term change in renal function after PCNL. PCNL in patients with bilateral kidneys has been shown to improve renal function; however, the long-term effect on patients with solitary kidneys is likely to be similar. Akman et al. [18] also showed that the renal function stabilized or improved in 90% of cases at more than 6 months of follow-up. The results of the present study are consistent with this finding and most cases in this series were associated with an improvement or stabilization in renal function. In the technical manipulation, why was the simultaneous use of flexible endoscopy and PCNL not advocated in these patients? First, when there is significant ongoing bleeding in PCNL, irrigation through the small working channel may not be adequate for good visualization during the RIRS procedures [2,19]. Secondly, the insertion of double-J stents following PCNL can dilate the ureter to a certain extent, which allows the flexible ureteroscope sheath to be easily introduced. In patients with difficult ureteral access or with an anticipated high risk of steinstrasse, sepsis and renal extravasation (such as patients with solitary kidneys), the insertion of a

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double-J stent was effective and safe to allow subsequent ureteroscopy in the passively dilated ureter [20,21]. Thirdly, it is postulated that lower intrapelvic pressure and less backflow from irrigation fluid could reduce the risks of bacteraemia and sepsis. In the present study, nephrostomy tubes were placed after PCNL. RIRS procedures were carried out 2–4 days after PCNL, before the tubes were removed. Irrigation fluid outflow through the nephrostomy tube may reduce the renal pelvis pressure. There are some limitations to this study. The nephrostomy tube may sometimes hide stone fragments. Furthermore, this was a retrospective and descriptive study. The best way to justify the technique was to compare it with multiple-tract PCNL in the same setting to determine the outcome and advantages. In conclusion, the combination of an initial singletract PCNL for stone debulking and a subsequent RIRS procedure for removal of residual stones was an effective strategy for the removal of staghorn stones in patients with solitary kidneys. There was a high SFR, satisfactory preservation of renal function, and reduced risk of the bleeding and morbidity that are known to be associated with multiple tracts. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

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Combination of debulking single-tract percutaneous nephrolithotomy followed by retrograde intrarenal surgery for staghorn stones in solitary kidneys.

The aim of this study was to report a therapeutic approach comprising a combination of debulking single-tract percutaneous nephrolithotomy (PCNL) and ...
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