Endoscopic Combined Intrarenal Surgery for Simultaneous Renal and Ureteral Stones: A Retrospective Study

Abstract

Purpose:

The management of simultaneous renal and ureteral calculi usually require staged procedure or change of position from supine lithotomy for ureterorenoscopic lithotripsy to prone for conventional percutaneous nephrolithotomy (PCNL). We review our experience with endoscopic combined intrarenal surgery (ECIRS) in the management of this condition.

Materials and Methods:

A total of 43 patients with simultaneous renal and ureteral calculi underwent ECIRS in Galdakao-modified supine Valdivia (GMSV) position from June 2012 to March 2016. Relevant demographic and clinical data were analyzed retrospectively. Clinical outcomes such as stone-free rate, complications, and hospital stay were evaluated. Factors predicting stone-free rate were also evaluated.

Results:

The mean ureteral stone size was 9.79 ± 2.11 mm and the mean renal stone size was 28.0 ± 11.4 mm. All patients with ureteral calculus were stone free after first intervention. The overall immediate renal stone success rate was 81.4%, which increased to 97% after auxiliary procedure. The overall complication rate was 32.5% with majority of complications (86%) classified under Clavien grade 1 and 2. Two patients had Clavien grade 3 complication with no grade 4 or 5 complications. The mean operative room occupation time was 132.09 ± 35.3 minutes. The median hospital stay was 6 days (range: 2–31). On analyzing for risk factors, only the number of involved calices by stone was significantly associated with stone-free rate following ECIRS (p = 0.03).

Conclusion:

ECIRS is a novel and excellent approach for the treatment of simultaneous renal and ureteral calculi with stone clearance and morbidity profile comparable to traditional prone PCNL. We believe that the advantage provided by this approach to the surgeon, patient, and anesthetist may lead to widespread adaptability of this technique in the management of complex urolithiasis.

Background

Multiple stones are not a uncommon finding in patients with urolithiasis. Approximately, 29% −36% of patients with multiple stones have simultaneous renal and ureteral stones.^1
–3 Various treatment options commonly practiced currently for this condition include ureterorenoscopic lithotripsy (URSL) followed by extracorporeal shock wave lithotripsy (SWL), flexible or rigid URSL and retrograde intrarenal surgery (RIRS), and URSL with conventional prone percutaneous nephrolithotomy (PCNL). Multiple treatment sessions may be required when SWL or RIRS is chosen as a treatment modality to achieve higher success rate.^4,5 Moreover, stone-free rates are inferior for renal stone >2 cm compared to PCNL.⁶

PCNL has been the standard treatment for kidney stones >2 cm for last three decades.⁷ The management of large renal stone with ureteral stones is usually accomplished by ureteroscopic lithotripsy and conventional prone PCNL. The advantages of prone position are larger surface area for puncture site and manipulation of instruments. The prone position has associated drawbacks such as respiratory and cardiovascular problems especially in obese and elderly patients with compromised cardiorespiratory status.^8,9 Other drawbacks are change of patient's position during the procedure, prolonged operative time, and nonfeasibility for simultaneous antegrade and retrograde access. To overcome these difficulties, different positions have been described in the last decade such as prone flexed,¹⁰ lateral,^8,11 prone split leg,^12,13 supine,^9,14 and modified supine psoition.^15,16 Recently, a novel approach in the modified supine lithotomy position is gaining popularity worldwide. Its advantages are easier anesthesia management, single positioning, and simultaneous anterograde and retrograde access to the urinary tract for management of renal and ureteral calculi.¹⁵

Although reports on supine PCNL have been published in literature for management of renal or ureteral calculi,¹⁷ data are lacking for supine PCNL in conjunction with retrograde access to the urinary tract for simultaneous renal and ureteral calculi. We studied the feasibility and outcome of management of this condition by using endoscopic combined intrarenal surgery (ECIRS) in Galdakao-modified supine Valdivia (GMSV) position to overcome difficulty in positioning and anesthesia management and decrease operative time.

Materials and Methods

From June 2012 to March 2016, 43 patients underwent ECIRS in GMSV position with the use of rigid nephroscope and semirigid ureteroscope for simultaneous ureteral and renal calculi. The study was conducted after obtaining clearance from the Ethics committee of our institute. The data were collected in a retrospective manner.

Operative procedure

The patients included in the study underwent ECIRS in GMSV position as described in literature under general anesthesia. The procedure was initiated by ureteroscopy of affected ureter with semirigid ureteroscope and fragmentation of ureteral calculus with Lithoclast^™ by assisting surgeon. Simultaneously, the affected renal collecting system was punctured with an 18-gauge puncture needle under ultrasonographic guidance in the desired calix and diluted radiological contrast instilled to delineate the pelvicaliceal anatomy using C-arm fluoroscopy. Then, a 0.035" J tip PTFE Guidewire was placed under fluoroscopic guidance and manipulated into the ureter. A double-shot dilation technique using a 10F fascial dilator followed by a 28F Amplatz dilator was performed. Thereafter, a 30F Amplatz sheath was inserted (by manipulating it over the 28F Amplatz dilator into the collecting system). Through this sheath, rigid nephroscopy and pneumatic lithotripsy were performed. The stone fragments were extracted using a stone forceps or a suction catheter. The assisting surgeon after completion of ureteroscopic lithotripsy, helped in clearing renal calculus by providing additional irrigation and breaking of stone fragments dropping in renal pelvis with lithoclast. After ensuring completeness of stone clearance, antegrade placement of a Double-J ureteral stent was performed by the assisting surgeon. A 12F nephrostomy tube was placed according to the surgeon's decision. All ECIRS cases in our study were completed through single percutaneous nephrostomy tract.

Outcomes

The stone size was measured with an X-ray kidney, ureter, and bladder region (KUB) or noncontrast computed tomography if radiolucent. Stone-free status was defined as no stone fragments visible or with residual stone fragments <3 mm on the postoperative image study. Postoperative complications were evaluated using the modified Clavien–Dindo classification system. Hospital stay was defined as the time interval from the day of surgery to the day of discharge.

Statistical methods

Continuous variables were summarized as mean ± standard deviation. Discrete data such as hospital stay were described as median with range. Categorical variables were summarized as frequency and percentage. Association between categorical outcome variable such as stone-free status with independent variables was measured using chi-square test or Mann–Whitney U test. Data were analyzed using Graph Pad Instat Software version 3.06. All statistical tests were two sided, level of significance was kept at 5%, and p-value <0.05 was considered significant.

Results

Out of the total 43 patients, 35 were males and 8 were females. Mean age was 47.6 ± 15.3 years. Table 1 lists the various patients', clinical, and perioperative characteristics.

Table 1.

Patient-, Stone-, and Operation-Related Data and Outcomes (n = 43)

1	Age in years (mean ± SD)	47.6 ± 15.3
2	Male/female ratio	35 (81.4%)/8 (18.6%)
3	BMI in kg/m² (mean ± SD)	23.81 ± 4.91
4	Comorbidity	21 (48.8%)
5	ASA category
	Category I	15 (34.9%)
	Category II	24 (55.8%)
	Category III	4 (9.3%)
6	Renal stone size in mm (mean ± SD)	28.0 ± 11.4
7	Stone number
	Single	21 (48.9%)
	Multiple	16 (37.2%)
	Staghorn	6 (13.9%)
8	Ureteral stone size in mm (mean ± SD)	9.79 ± 2.11
9	Ureteral stone location
	Lower	17 (39.5%)
	Upper	26 (60.5%)
10	Preoperative hemoglobin in gm/dL (mean ± SD)	11.93 ± 2.18
11	Preoperative serum creatinine in mg/dL (mean ± SD)	1.89 ± 1.67
12	Postoperative hemoglobin in gm/dL (mean ± SD)	10.68 ± 2.06
13	Postoperative serum creatinine in mg/dL (mean ± SD)	1.53 ± 1.41
14	Postoperative hemoglobin drop in gm/dL (mean)	1.25
15	Postoperative serum creatinine drop in mg/dL (mean)	0.36
16	Kidney side, right/left	18/25 (41.9%/58.1%)
17	Calix for puncture access
	Upper group	3 (7%)
	Middle group	16 (37.2%)
	Lower group	24 (55.8%)
18	Operative room occupation time in minutes (mean ± SD)	132.1 ± 35.3
	Initial 15 cases (mean ± SD)	164.0 ± 19.2
	Last 28 cases (mean ± SD	113.9 ± 30.1
19	Intraoperative nephrostomy tube insertion
	Yes	42 (97.7%)
	No	1 (2.3%)
20	Blood transfusion requirement	6 (13.9%)
21	Stone-free rate (no residual calculus or residual fragments <3 mm at day 1 after operation)	35 (81.4%)
22	Stone-free rate after redo intervention	42 (97.7%)
23	Complications	14 (32.5%)
24	Hospital stay in days (median with range)	6 (2–31)

SD = standard deviation.

At the end of first intervention, all patients achieved complete clearance with respect to ureteral calculus. The overall immediate renal stone-free rate was 81.4% in our series. Eight patients (18.6%) required a secondary procedure, either relook nephroscopy or SWL. The overall renal stone-free rate after secondary procedure was 97.7%. Table 2 demonstrates the renal stone-free rate after primary procedure and after secondary procedure with respect to stone number. On analyzing for factors associated with stone-free rate following ECIRS, only the number of involved calices by stone was found to be significant (p = 0.03) (Table 3).

Table 2.

Stone-Free Rate According to Stone Number

	After primary procedure	After redo intervention
Single calculus (n = 21)	19 (90.5%)	21 (100%)
Multiple calculi (n = 16)	12 (75%)	15 (93.7%)
Staghorn calculus (n = 6)	4 (66.7%)	6 (100%)

Table 3.

Association of Clinical Factors with Stone Free Rate

	No residual calculus (n = 35)	Residual calculus (n = 8)	P
Age in years (mean ± SD)	49.57 ± 14.39	38.87 ± 17.07	0.12^a
BMI in kg/m² (mean ± SD)	24.32 ± 5.08	21.57 ± 3.54	0.24^a
Gender
Male	30	5	0.30^b
Female	5	3
Stone bulk in mm (mean ± SD)	27.0 ± 10.5	32.5 ± 14.8	0.32^a
Stone number
Single	19	2	0.12^c
Multiple	12	4
Staghorn	4	2
Number of calices involved by stone
One	20	1	0.03^c
Two	9	4
Three or more	6	3
Puncture site
Inferior calices	20	4	0.56^c
Middle calices	13	3
Upper calices	2	1

Mann–Whitney U test; ^bchi-square test; ^cchi-square for trend.

The complications according to Clavien–Dindo classification are given in Table 4. Intraoperatively, two patients had medial pelvic wall injury, which was managed with conservative management by nephrostomy tube and Double-J stent placement. One patient had bleeding intraoperatively; so procedure was abandoned and redo PCNL was performed after 72 hours. Six patients required blood transfusion during intraoperative or postoperative period. Out of these six patients, three patients had hemoglobin level ≤8 gm/dL preoperatively and the other three patients had staghorn calculus with longer operative time. Other complications included fever in 10 patients (including SIRS in 2) and 1 patient had nephrostomy site abscess requiring incision and drainage. Two patients had bowel complications in the form of paralytic ileus in one and colonic injury in another. The patient with paralytic ileus recovered with conservative management, while the patient with colonic injury required temporary ileostomy.

Table 4.

Clavien–Dindo Classification of Complications (n = 43)

Grade 0	29 (67.5%)
Grade 1	5 (11.6%)
Grade 2	7 (16.3%)
Grade 3	2 (4.7%)
Grade 4	0
Grade 5	0

Discussion

PCNL is the preferred minimal invasive treatment for high-burden urolithiasis because of excellent outcomes and low morbidity.⁷ Supine PCNL is as effective as prone PCNL in terms of stone-free rate and complications.¹⁸ A recent innovation, the modified supine lithotomy position, offers a considerable improvement in this technique, opening the era of ECIRS. However, only limited centers are practicing this technique due to nonfamiliarity.

Our study demonstrates a stone-free rate of 81.4% after first intervention and 96.7% after auxiliary treatment, which is comparable to the stone-free rate of supine PCNL and prone PCNL already reported in literature.¹⁸ Kuroda and colleagues reported a success rate of 65.3% after a single session of ECIRS for renal stones.¹⁹ Nuño de la Rosa and colleagues in a retrospective comparative study found superior success rate for the ECIRS group (75.3% vs 40.8%) compared to supine PCNL.²⁰ Ninaad and colleagues in a retrospective review of 100 patients with ECIRS reported stone-free rate of 87% after the initial procedure.²¹ Wen and colleagues in a comparative study of 67 patients found significantly higher success rate (87.88% vs 58.82%) for ECIRS group compared to mini-PCNL group.²² Hamamoto and coworkers also observed a 71.4% stone-free rate in patients who underwent ECIRS using retrograde flexible ureteroscopy and miniature PCNL in the prone split-leg position.²³ While this technique also accomplishes stone clearance without change of position similar to ECIRS in supine position, the use of a flexible ureteroscope requires expertise and is associated with higher costs due to the wear and tear of flexible ureteroscopes, need for laser intracorporeal lithotripters, and the need for costly consumables. This can be a handicap in centers like ours, with limited resources. Supine ECIRS allows us to use rigid instruments and cheaper lithotripters such as pneumatic lithotripters, and the use of flexible cystoscope can be restricted to inspection of the calices at the end of the procedure to ensure complete stone clearance.

Kan and associates have reported the outcomes of 11 patients with either renal or upper ureteral stones treated with supine PCNL and retrograde semirigid ureteroscopy in a prospective study.²⁴ They achieved 55% stone-free rate after single procedure, while on follow-up, only 20% patients required secondary treatment. Our study also demonstrates a similar success for the management of complex renal and ureteral stones with 18% patients requiring secondary procedure. Hoznek and coworkers also had three simultaneous renal and ureteral calculi in their study of supine PCNL for renal calculi, which were managed with supine PCNL and URSL. They also had 81% success rate for renal calculi and 100% for ureteral calculi, similar to our study.¹⁷

We found a significant association between the number of involved calices by stone and stone-free rate after a single session of ECIRS (p = 0.03). Kuroda and colleagues also found that the number of involved calices and stone surface areas were predictors for a stone-free rate following ECIRS.¹⁹ We had a higher stone-free rate for single renal stone compared to multiple or staghorn calculus, but this difference was not statistically significant. Hamamoto and coworkers reported that complete staghorn calculi, stone surface area, stone size, and the number of stone branches were risk factors for residual calculus.²³

The complication rate of 32.5% in our series is well within the range reported in literature (28.8 − 38.6).^15,19 Approximately, 86% of complications in our study fell into Clavien grade 1 and 2. Only two patients developed complications requiring surgical intervention. One patient who developed colocutaneous fistula caused by bowel injury required temporary diverting ileostomy. Although we routinely use intraoperative ultrasound guidance for making the initial puncture in supine PCNL, in the patient with the colonic injury, we had to resort to fluoroscopy for the initial puncture as our ultrasound machine malfunctioned in the operative room (OR). This patient was one of the earlier candidates in our series, when we started this technique in our institution. Although a few institutions use fluoroscopic technique for the initial puncture, we made a policy to use ultrasound only for the initial puncture. This has prevented the recurrence of this complication. This complication developed during the early part of our series. Another patient who developed abscess at the nephrostomy site required incision and drainage under local anesthesia. There were no Clavien grade 4 and 5 complications and no perioperative adverse anesthesiological outcomes in our study. Scoffone and associates reported an overall complications rate of 38.6% with no splanchnic injuries, deaths, or anesthesiological complications.¹⁵ Nuño de la Rosa and colleagues quoted a complication rate of 28.8% in the ECIRS group vs 28.3% in the supine PCNL group.²⁰

Two meta-analyses suggest that supine PCNL offers similar clinical outcomes with a significant reduced operative time compared to prone PCNL.^18,25 ECIRS in the GMSV position facilitates the completion of ureteroscopic procedure at the same time. Therefore, the operative time for ECIRS in the GMSV position would be expected to be much shorter than that for URSL, followed by PCNL in the prone position as URSL takes place simultaneously with PCNL. Our mean OR occupancy time (patient's position and operative time) was 132.1 ± 35.3 minutes, which is consistent with the time reported in literature ranging from 70 to 143 minutes.^15,23 Our OR occupancy time falls in the higher range of that reported in literature, due to the learning curve in the initial study period with regard to patient positioning and equipment arrangement by OR staff. In the later part of the study, we observed a decrease in our operative duration as mentioned in Table 1.

The patients in our study had a median hospital stay of 6 days (range 2–31 days), while the average hospital stay reported in literature ranges from 2 to 5 days.^15,20,21 The possible reason for the longer hospital stay in our study may be because of two reasons: one, our policy is to discharge patients 1 day after nephrostomy removal. Second, it can be attributed to the waiting period for relook nephroscopy in patients with residual calculus because of scheduling issues. While patients could have been discharged and readmitted for the second look, this was not our department policy. Furthermore, one patient with bowel injury required hospitalization for 31 days.

The advantage of ECIRS in GMSV position is that it reduces the operative time and overcomes the risk associated with change in position under general endotracheal anesthesia. Good irrigation system, both retrograde and antegrade, allows excellent vision and better stone clearance rates as stone particles are irrigated out with good irrigant flow. Another advantage of ECIRS is less physical discomfort to the operating surgeons as both surgeons can sit and work simultaneously. ECIRS is also advantageous to the obese, chronic obstructive pulmonary disease (COPD), and cardiovascular high-risk patients compared to conventional PCNL.^8,9

Disadvantages of the procedure include the need for two operating surgeons, ultrasonography machine in the OR, two endovision systems to work simultaneously, and a steep learning curve. Therefore, preparing the setup for ECIRS may be costly compared to conventional PCNL, so may not be feasible for community urologists. This procedure may be more suitable to tertiary care hospitals and academic teaching institutions where facilities for intra-OR ultrasonography and two endovision systems may be available. Beside this, trainee resident doctors at these institutions may work as second operative surgeon.

There are limitations in our study. It is a retrospective study. The design of this study is descriptive rather than comparative, with small number of patients. Also, we have not attempted to compare costs of this technique with conventional procedures. We have avoided this because the treatment in our institution is free to the patients and costs would vary based on cost of consumables, OR time, hospital stay, and payment patterns in different centers and countries. While a randomized multi-institutional study with a large sample size would be ideal to confirm our outcomes, we feel this is not going to be practical due to various reasons such as variations in patient preferences, surgeons' comfort, and also variations in costs in different centers.

Conclusion

ECIRS is a novel and effective approach for the treatment of simultaneous renal and ureteral calculi. This approach is perhaps more favorable for the surgeon, patient, the OR team, and the anesthetist when compared to the classic prone position. Stone clearance rates and morbidity seem to be comparable to that reported in prone PCNL. The number of involved calices by the calculus seems to be the only predictor for the stone-free rate in our study. To the best of our knowledge, this is the largest series reporting the management of combined renal and ureteral calculus using the ECIRS technique. We, therefore, recommend the widespread adaptation of ECIRS technique in the GMSV position, particularly in the management of complex urolithiasis.

Footnotes

Author Disclosure Statement

No competing financial interests or other conflicts of interest exist among any of the authors.

Abbreviations Used

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