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Table of Contents
Year : 2022  |  Volume : 33  |  Issue : 3  |  Page : 152-156

Comparison between tubeless mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for the treatment of 2 to 3cm renal lithiasis

Department of Urology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan

Date of Submission05-Apr-2021
Date of Decision26-Nov-2021
Date of Acceptance12-Jan-2022
Date of Web Publication25-Aug-2022

Correspondence Address:
Yeong-Chin Jou
539 Chung-Hsiao Road, Chiayi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/UROS.UROS_54_21

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Purpose: To assess the outcome and safety of tubeless mini-percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) to treat patients with renal and upper ureteral stones between 2 and 3 cm. Materials and Methods: Between July 2017 and June 2020, 140 patients underwent tubeless mini-PCNL and RIRS for renal stone size between 2 and 3 cm were enrolled in this study. The outcome was determined immediately after operation on plain radiograph kidney, ureter, and bladder and sonography. Various patient and stone characteristics including perioperative outcomes and complications were evaluated. SPSS version 16. Institutional Review Board of Ditmanson Medical Foundation Chia-Yi Christian Hospital, approval number 2021037. Results: Stone-free rates after the procedure were achieved in 78.4% of patients for the tubeless mini-PCNL and 36.4% of patients for the RIRS Group (P < 0.001). However, the stone-free rates at 3 months after surgery were 78.4% for the tubeless mini-PCNL and 68.2% of the RIRS Group (P = 0.172). The mean operative time per patient was 88.6 ± 27.4 min in the tubeless mini-PCNL group, and it was 129.1 ± 44.8 min in the RIRS groups (P < 0.001). The average hospital stay is 3.4 ± 2.0 days in the tubeless mini-PCNL group and 1.9 ± 1.8 days in the RIRS group (P < 0.001). The postoperative infection rates for the tubeless mini-PCNL and RIRS groups were 9.5% and 6.1%, respectively (P = 0.456). Blood transfusions were needed in one patient in the tubeless mini-PCNL group. Conclusion: Tubeless mini-PCNL and RIRS are safe and effective methods for medium-sized renal calculi. Tubeless mini-PCNL compared to RIRS offers the better outcome of higher stone-free rate and lower operation time, but with longer hospital stay and stone-free rate (3-month postoperative).

Keywords: Kidney stones, mini-percutaneous nephrolithotomy, retrograde intrarenal surgery

How to cite this article:
Lee YC, Jou YC, Cheng MC, Shen CH, Lin CT. Comparison between tubeless mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for the treatment of 2 to 3cm renal lithiasis. Urol Sci 2022;33:152-6

How to cite this URL:
Lee YC, Jou YC, Cheng MC, Shen CH, Lin CT. Comparison between tubeless mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for the treatment of 2 to 3cm renal lithiasis. Urol Sci [serial online] 2022 [cited 2023 Jan 31];33:152-6. Available from: https://www.e-urol-sci.com/text.asp?2022/33/3/152/354713

  Introduction Top

Elimination of upper urinary tract stones via percutaneous access is more effective than open stone surgery with lower morbidity. Other advantages of percutaneous nephrolithotomy (PCNL) compared with open surgery include ease of performing secondary procedures, shorter patient recovery, and cost-effectiveness.[1] Despite the extensive use of extracorporeal shock wave lithotripsy (ESWL), PCNL still plays an essential role in treating complicated upper tract urinary stone disease. To minimize the postoperative morbidity related to conventional PCNL, new modalities of practice in endourology have been reported constantly in recent years, such as tubeless PCNL, mini-PCNL, and retrograde intrarenal surgery (RIRS) for removing upper urinary tract stones by flexible ureteroscope (fURS).

Since Bellman et al. first reported PCNL without a nephrostomy tube after the procedure in 1997, tubeless PCNL has been extensively evaluated.[2] It has been consistently associated with a shorter hospital stay, shorter time to return to normal activities, less postoperative pain, less need for analgesia, reduced urine leakage, and no increase in overall morbidity compared with conventional PCNL.[3],[4] Mini-PCNL was developed to reduce surgical morbidity, decrease patient discomfort, and increase lithotripsy efficiency by minimizing the diameter of the nephroscope. It is as effective and safe as the conventional PCNL for removing renal calculi.[5] Advances in the design and use of fURS and dedicated laser lithotripsy have led to increased use of RIRS to treat upper urinary tract stones. A systematic review and meta-analysis published by De et al. in 2015 suggested that RIRS should be considered a standard treatment for stones <2 cm in size.[6] RIRS has also been found safe and effective for treating stones >2 cm in size with a high stone-free rate, significantly shorter hospital stay, and no increased complications compared with PCNL.[7]

Despite improvements in endoscopic equipment and surgical techniques and the development of novel methods for treating urinary stone disease, no single treatment modality is currently considered optimal. Several studies have evaluated the surgical results between mini-PCNL and RIRS for treating upper urinary tract stone disease, but reports comparing tubeless mini-PCNL and RIRS are presently unavailable. This retrospective study compared the clinical characteristics and outcomes of patients with kidney stones sized >2 cm and ≤3 cm in size who received treatment with tubeless mini-PCNL or RIRS.

  Materials and Methods Top

A series of 140 consecutive patients treated at our hospital with tubeless mini-PCNL or RIRS for upper tract urinary stones >2 cm and ≤3 cm in size between July 2017 and June 2020 were enrolled. The same well-experienced endourologic team performed all surgical procedures. The indications for surgery included a significant stone burden, failed shock wave lithotripsy (SWL), calyceal, or lower pole renal stones. The patient made the choice of mini-PCNL or RIRS after the two types of surgery were described by the surgeons in detail. Patients who underwent bilateral procedures were excluded from this study.

In tubeless mini-PCNL, an occlusive balloon catheter was inserted cystoscopically at the start of the procedure. The renal puncture was performed under ultrasound guidance, and the renal access tract was dilated using a coaxial metal dilator to permit the insertion of a 15-F miniature nephroscope (Richard Wolf, Knittlingen, Germany). The stone was disintegrated using a ballistic lithotripter, and after completing the stone removal, a double J catheter was inserted antegradely, and the renal access tract was packed with oxidized regenerated cellulose strips (Surgicel®, Ethicon Inc., Somerville, NJ, USA) without the placement of a nephrostomy tube. The access tract wound was closed with a suture, and a foley catheter was inserted for overnight urinary drainage.

In RIRS procedures, a 6-F semirigid ureteroscope was used to inspect the ureter as far as the ureteropelvic junction. After inspection, a 9–F ureteral sheath was inserted, and a 7.5–F fURS (Karl Storz, Tuttlingen, Germany) was passed through the access sheath and placed in the renal pelvis. The stones were disintegrated with a 30 or 60-W Holmium YAG laser (Quanta, Milan, Italy) and a 200-mm laser fiber by dusting, fragmentation, or popcorn mode depending on the size, position, and hardness of the stone. A double J catheter was inserted at the end of the procedure. The flexible ureteroscopy procedures were performed with fluoroscopic guidance. A routine kidney-ureter-bladder film immediately after each mini-PCNL and RIRS procedure verified the stent insertion and stone-free status. Stone-free was defined as the absence of stone fragments or fragments >3-mm on kidney, ureter, and bladder radiography immediately after surgery and 3 months postoperatively. The clinical course was evaluated using a retrospective chart review.

Statistical analysis was performed using the Chi-square or independent sample Student's t-test. Univariate and multivariate binary logistic regression models were used to determine the efficacy of both procedures. Crude and adjusted odds ratios with their 95% confidence intervals were estimated from exponential regression coefficients. The significance level was P = 0.05. This study was approved by Institutional Review Board of Ditmanson Medical Foundation Chia-Yi Christian Hospital, approval number 2021037.

  Results Top

A total of 140 patients were included in this study, 74 with mini-PCNL and 66 with RIRS [Figure 1]. The mini-PCNL procedures were tubeless and completed with a single percutaneous tract. The patient and stone characteristics of both groups are shown in [Table 1]. The mean age, gender, and stone size of each group did not differ significantly. The body mass index (BMI) was 25.6 ± 5.4-mm in the mini-PCNL group, and 27.5 ± 5.0 -mm in the RIRS group, the BMI in the RIRS group was significantly greater than the mini-PCNL group (P = 0.03). The peri- and postoperative characteristics are shown in [Table 2]. The operation time of mini-PCNL procedures (888.6 ± 27.4 min) was shorter than the RIRS procedures (129.1 ± 44.8 min), the difference was statistically significant (P < 0.001). The stone-free rate after a single procedure was higher in mini-PCNL (78.4%) group than in RIRS group (36.4%, P < 0.001). However, the stone-free rates 3 months after surgery were 78.4% for the tubeless mini-PCNL and 68.2% of the RIRS group (P = 0.172). The stone-free rate of lower pole stone was higher in mini-PCNL (58.8%) group than in RIRS group (12.0%, P = 0.001). The outcome of the stone-free rate for nonlower pole stones was 84.2% in the mini-PCNL group and 51.2% in the RIRS group (P < 0.001). The average postoperative hospital stay in the mini-PCNL (3.4 ± 2.0 days) was significantly longer than in the RIRS groups (1.9 ± 1.8 days). No significant complication was reported during this study. Postoperative infections, sepsis and blood transfusion rates were statistically insignificant between both groups. Preoperative and postoperative (in the evening of operative day) hemoglobin levels were recorded in 32 patients in the mini-PCNL group and all patients in RIRS, there was no significant change in the hemoglobin level in both groups (-0.1 ± 0.8 and 0.1 ± 1.1 respectively).
Figure 1: Flow chart of patient selection

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Table 1: Patient and stone characteristics in the two study groups

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Table 2: Intraoperative and postoperative outcomes of patients in the mini - percutaneous nephrolithotomy and retrograde intrarenal surgery groups

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Postoperative complications were classified using a modified Clavien grading system. Because the evaluation was retrospective, grade 1 complications could not be estimated. Severe, ≥ clavien grade 2 complications that required treatment occurred in 12 patients, eight in the mini-PCNL and four in the RIRS group. Urinary tract infections requiring additional antibiotics occurred in seven mini-PCNL patients (9.5%) and four patients RIRS patients (6.1%). The postoperative urinary tract infection rate was higher in the mini-PCNL group but not statistically significant (P = 0.456). One mini-PCNL patient needed a transfusion of packed RBC after the procedure. As noted, two patients in the PCNL group (2.7%) and one patient in the RIRS group (1.5%) experienced urosepsis classified as clavien grade 4. No switch to open surgery or mortality occurred.

  Discussion Top

Kidney stones occur frequently. The prevalence of kidney stones is estimated to be 8.8% in the United States, where they affect approximately 1 in 11 people in the general population.[8] Recent increased prevalence of urinary stone disease has been reported globally, including in the United States, United Kingdom, Iceland, and Japan.[9],[10],[11] Due to the high rates of new growth and recurrence, managing urinary stones has been an important work in daily urologic practice. Most symptomatic patients have small stones that pass spontaneously without the need of surgical treatment. However, many patients with urinary stone disease do require surgical treatment.[12] SWL and URS can successfully treat most stones that do not spontaneously pass, but PCNL still has an important place in managing urinary stone disease. The American Urological Association and the European Association of Urology guidelines recommend PCNL as first-line therapy in patients with a total renal stone burden >20 mm,[13],[14] but PCNL is associated with clinically significant morbidity. In a prospective, international multicenter evaluation of 5803 consecutive patients treated with PCNL, de la Rosette et al. reported 11.1% clavien grade I, 5.3% grade II, 2.3% grade IIIa, 1.3% grade IIIb, 0.3% grade IVa, 0.2% grade IVb, and 0.03% grade V surgical complications.[15] The frequencies of major PCNL-associated complications reported in 2008 by Skolarikos and de la Rosette were 0.9%–4.7% for septicemia, 0.6%–1.4% for renal hemorrhage requiring intervention, 2.3%–3.1% for pleural injury, and 0.2%–0.8% for colonic injury.[16] Tubeless modifications, mini-PCNL and RIRS are intended to mitigate the morbidity associated with conventional PCNL. In 1998, Jackman et al. reported that mini-PCNLs performed with a 13-F working sheath resulted in less hemorrhage, less postoperative pain, and shortened hospital stay in selected patients compared with conventional PCNLs.[17] An earlier comparison of 40 mini-PCNLs, 67 standard PCNLs, and 27 tubeless PCNLs for renal stones <2 cm in diameter failed to show significant advantages of the mini-PCNL technique compared with traditional PCNL.[18] Improvement in surgical techniques and endoscopic devices has improved mini PCL outcomes. A prospective evaluation by Mishra et al. in 2011 evaluated the efficacy of mini-PCNL and conventional PCNL for treating 1–2 cm renal stones and found that mini-PCNL was as effective as SFR, less bleeding, and a shorter hospital stay than conventional PCNL.[19] A 2016 study of 133 consecutive patients with renal stones ≥2 cm treated using either mini- or conventional PCNL found no significant differences in primary stone-free or complication rates observed with either method, indicating that mini-PCNL was as effective as conventional PCNL for treating large renal calculi.[20]

fURSs have been used in urological practices for many years, and the availability of dedicated RIRS, laser lithotripters, and accessory devices, such as access sheaths and stone extraction tools has expanded the role of RIRS for treating kidney stone disease. In a matched-pair analysis of 34 patients with 2–4 cm renal stones treated using RIRS or PCNL, the stone-free rates were 73.5% after one RIRS session and 91.2% after PCNL. The RIRS stone-free rate improved to 88.2% after the second procedure.[21] A prospective evaluation of 64 patients, 32 with mini-PCNL and 32 with RIRS, reported high stone clearances and low complication rates with both modalities. The RIRS procedures took a longer operative period than mini-PCNL, but had favorable pain scores and lower hemoglobin drops.[22] A prospective randomized comparison of SWL, PCNL, and RIRS for treating lower calyceal stones of 1–2 cm reported by Bozzini et al. in 2017 found overall stone-free rates of 61.8% for ESWL, 82.1% for RIRS, and 87.3% for PCNL with complication rates of 6.7%, 14.5%, and 19.3%, respectively. RIRS and PCNL were thus considered more effective than SWL, with better stone-free rates in patients with a single lower calyceal stone of approximately 1–2 cm.[23] Tubeless PCNL is a safe alternative for upper urinary tract stone disease and has advantages of a short hospital stay, short time to return to normal activities, low postoperative pain scores, and analgesic requirements, and low urine leakage.[24] A prospective randomized controlled trial by Lee et al. in 2014 in 35 mini-PCNL patients and 33 RIRS patients with renal stones >1.0 cm found that both procedures were safe and effective surgical alternatives and that RIRS had a slightly higher stone-free rate.[25] A systematic review and meta-analysis published by Jiang et al. in 2017 reported that mini-PCNL had a significantly higher stone-free rate than RIRS but had a higher incidence of postoperative complications and longer hospital stay.[26] However, the study concerning tubeless PCNL and RIRS has never been reported before. These results align with previous reports finding that tubeless mini-PCNL achieved a significantly higher stone-free rate (immediately after surgery), hospital stay, and lower operation period than RIRS. There is no statistical difference in surgical complications between tubeless mini-PCNL and RIRS. In addition, there is no statistical difference in stone-free rate (3 months postoperatively) between tubeless mini-PCNL and RIRS.

This study's limitations include its retrospective nonrandomized design. In Taiwan, the National Insurance Bureau covers almost all the medical expenses incurred during the treatment of kidney stones except fURS surgery, which costs about $1500 US in our hospital. For that reason, the group assignments could not be random. The other limitation is in the era of endoscopic combined intrarenal surgery (ECIRS), the combination of PCNL and RIRS has been proven to be a more efficient modality in treating upper urinary tract disease. Due to unfamiliarity with (modified) supine PCNL, ECIRS is seldom conducted at our hospital. With the accumulation of the experience of ECIRS, its efficacy in treating large upper urinary tract stone disease will increase reasonably.

  Conclusion Top

Tubeless mini-PCNL and RIRS are safe and effective methods for medium-sized renal calculi. The tubeless mini-PCNL compared to RIRS offers a better outcome of a higher stone-free rate and lower operation period, but with a longer hospital stay and stone-free rate (3-month postoperative). However, studies with a larger cohort must be conducted to further validate the efficacy of this method.

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  References Top

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  [Figure 1]

  [Table 1], [Table 2]


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