Combined Flexible Ureteroscopy and Laser Lithotripsy for Complex Unilateral Renal Calculi

Flexible ureteroscopy and lasertripsy for the treatment of multiple and bilateral renal calculi greater than 2cm in diameter is associated with high success rates. The presence of lower calyceal stones remains more difficult than in other anatomical positions but is still associated with a stone free rate of over 87.5 %. We believe fURS can become a first-line option of treatment for these patients.

Keyword: Flexible Ureteroscopy, laser lithotripsy, renal Calculi

Introduction & Objectives: The treatment indications for flexible ureteroscopy and lasertripsy (FURSL) for urolithiasis have yet to be definitively defined. Currently, the EAU recommends renal calculi <20mm are treated with extracorporeal shockwave lithotripsy (ESWL). However evidence suggests that success rates are significantly affected by stone position (lower calyx), renal anatomy and stone size. This is acknowledged in current EAU guidelines though this only goes as far as suggesting ureteroscopy is carried out where ESWL is contraindicated. There is a lack of data for FURSL and we present a large case series of larger and multiple renal calculi treated with FURSL.

Material & Methods: We retrospectively analyzed 46 urological patients with single or multiple renal calculi at least 1cm in diameter treated with FURSL in the department of urology of China-Japan Union Hospital of Jilin University between March 2013 and March 2014. 13 patients had prior treatment in the form of PCNL. Stone free rates status was defined as fragments less than 3mm on follow up imaging in the form of ultrasound, KUB or CT. Flexible ureteroscopy was carried out under prophylactic antibiotic cover (intravenous cefuroxime depending on renal function). A ureteric access sheath (10F Peel away Cook) was routinely inserted over a guidewire prior to ureteroscopy. The flexible ureteroscope utilised was either a Polydiagnost modular flexible ureteroscope or a Storz URF-P4 or 5. Lower calyceal stones were disrupted in situ if possible or basketed to the renal pelvis or upper calyx prior to lasertripsy. A Lumenis 100w device was utilized for lasertripsy through a 200m fibre where possible. A 6F multilength stent (Cook) were left postoperatively and removed the following day or 4 weeks later respectively.

Results: Forty-six patients were identified with a mean stone size per patient of 8.6±3mm (range: 2– 16). The mean number of stones per patient was 3.1± 1 (range: 2–6). The overall stone-free rates after one and two procedures were 71.7 % and 91.3 %, respectively. The stone-free rates for patients with a stone burden greater than and less than 20 mm were 87.5 % and 100 %, respectively. The overall complication rate was 15.2 %. There are some limitations to this study, however: This is a retrospective review from a single institution, and our results are based on a relatively small sample size.

1. Introduction

In the era of extracorporeal shock wave lithotripsy (ESWL), the stone clearance rate for renal calculi was found to decrease as the stone sizes increase, especially with stone sizes >2 cm in diameter ^[1]. Therefore, ESWL is recommended only when the size of a renal calculus is <2 cm in diameter. Percutaneous nephrolithotomy (PCNL) is favored when the size of a renal calculus is >2 cm. According to the Chinese Urological Association (CUA) treatment guidelines in 2014 and an announcement of the American Urological Association guidelines, PCNL is the first choice of treatment for the majority of staghorn stones that are >500 mm² or >2.5 cm in standardized index patients ^[2]. The earlier literature reported that ureteroscopic lithotripsy (URSL) was considered an adjunct therapy in combination with PCNL for staghorn stones ^[3]. Considering major complications arising out of performing a PCNL, in addition to technological advancements of flexible ureteroscopes and ancillary equipment, such as the holmium laser and ureteral access sheath, flexible ureteroscopy with holmium laser lithotripsy was proven to be a feasible and an effective alternative therapy with low morbidities in selected patients, whose renal stones are not <2 cm ^[4]. From these considerations, here we present a review of the literature with regard to stone-free rates, complications, the number of procedures needed, and cost analysis.

2. Methods

A retrospective review of 46 urological patients with single or multiple renal calculi in the department of urology of china-Japan union hospital of Jilin university between March 2013 and March 2014 was conducted. This review identified 46 consecutive patients with multiple intrarenal stones who underwent flexible ureteroscopy and Lumenis laser lithotripsy by a single surgeon. Chart review was used to obtain patient, stone, and treatment parameters. The indications for ureteroscopy in this series included multiple intrarenal stones that failed PCNL, obesity, and patient preference. Contraindications for ureteroscopy included severe hydronephrosis and stones in a lower-pole diverticulum. All patients were offered ESWL and PNL as alternative treatment modalities. Informed consent was obtained and included specific mention of the possible need for multiple ureteroscopic procedures to treat the multiple intrarenal stones, the need for a second-look diagnostic procedure, and stent placement. All patients underwent a preoperative computed tomography (CT) urogram to define the collecting system anatomy and the total stone burden (measured as the cumulative diameter of the intrarenal stones) and to ensure that the stones were not harbored within a diverticulum or the parenchyma of the kidney.

2.1. Technique

Prior to the start of the procedure—under general anesthesia—patients were placed in the dorsal lithotomy or low lithotomy position, and intravenous antibiotics were given. The bladder

was entered with a 22F cystoscope, and the ureteral orifice was cannulated with an open-ended 5F catheter and a 0.038-mm guidewire. A second 0.038-mm guidewire was placed under fluoroscopic guidance with the use of a Flexi-Tip Dual Ureteral Access Catheter (Bard Medical, IN, USA). The use of these tools allows for dilation of the ureteral orifice and placement of a second guidewire. In the majority of cases, dilation with these tools was adequate and obviated the need for balloon dilation. A ureteral access sheath (12/14F, Cook, Amerian) was placed to allow for optimal visualization, to maintain low intrarenal pressure, and to facilitate extraction of stone fragments. A modular flexible ureteroscope (Polydiagnost, Germany) and a 200-micron laser fiber were used for treatment. The holmium laser was set at an energy level of 0.6–0.8 J and at a rate of 10–25 Hz. Following lithotripsy, a double-J stent was placed. Basketing of the fragments was only deemed necessary in cases with residual fragments >2 mm after multiple procedures. When basketing was deemed necessary, a 2.2F zero-tipped nitinol stone basket (Cook Medical, Bloomington, IN, USA) was used. All patients were evaluated after the last therapeutic treatment with ultrasound and CT to ensure that the patient was stone free before stent removal. Furthermore, all patients underwent a renal ultrasound 30 d from the second-look procedure to ensure the absence of hydronephrosis and to document the final stone burden. We defined stone-free status as the absence of fragments in the kidney or fragments <3mm, which are too small to be extracted with a basket or grasper by ureteroscopic inspection. For some patients, pain medications as needed.

3. Results

On retrospective analysis, there were 46 patients: 26 males and 20 females. The mean patient age was 43.5±11.6 (Table 1). In all patients, the mean stone size per patient was 12.6 ±3mm(range: 5–28), with amean total stone burden of 25±6mm (range: 13–36). Thirty-two patients (69.6 %) had a stone burden >20mm, and fourteen patients (30.4 %) had a stone burden <20mm (Table 2).

Table 1

Patient demographics

Table 2

Stone-free rates for patients with stone burden≤2 cm and >2 cm

3.1 Complications

There were two (4.3 %) intraoperative complications. Two patients had significant bleeding, which resulted in poor visibility and led to abortion of the procedure. For one of them, transfusions were necessary. One patient underwent an uncomplicated second treatment 2 weeks later. Another patient had a successful operation 3 month later. One postoperative major complication (2.2 %) occurred. This patient developed pyelonephritis three day after his procedure, and was admitted to the hospital for intravenous antibiotics. He was fully recovered in 7 days. Four minor postoperative complications (8.7 %) occurred consisting of urinary tract infections (UTI). All were treated with antibiotics.

4. Discussion

Although technologic advances in flexible ureteroscopy make most areas of the kidney accessible, indications for ureteroscopic management of renal calculi remain debated. Because of the small number of prospective comparative study publications, neither the CAU nor the AUA guidelines recommend ureteroscopy as a first-line treatment of choice for single or multiple unilateral renal stones ^[5].

Shock wave lithotripsy (SWL) has traditionally constituted the favored approach for small to moderate size intrarenal calculi (<20 mm), although ureteroscopy has assumed an increasing role in recent years. The highest stone-free rates (80 %–88 %) were achieved with SWL to calculi in the renal pelvis. Success rates are lower in the upper pole (73 %), midpolar (69 %), and lower (63 %) pole calices ^[6–7]. When multiple intrarenal stones are managed with SWL, however, the stone-free rate drops down to 50 % to 55 % ^[8].Our study emphasizes that ureteroscopy can be performed safely and effectively for a select group of patients with multiple unilateral intrarenal stones. The overall stone-free rates after one and two procedures were 64.7 % and 92.2 %, respectively. This stone-free rate is similar to previously reported series of PNL and SWL in literature

A prospective series for lower-pole renal calculi <10mm suggested higher patient satisfaction in the SWL treatment arm. In this prospective randomized study, ureteroscopy had a higher stone-free rate, but this difference failed to reach statistical significance. Also, ureteroscopic treatment of intrarenal calculi has a low complication rate, regardless of calculus size (less than or greater than 20 mm), and can be performed as an outpatient procedure.

PCNL, on the other hand, has a significantly higher stonefree rate than SWL (86 %–100 %) and is the standard of care for single, complex (>20 mm), or >10mm lower-pole stones as well as for multiple intrarenal stones. It is associated, however, with greater morbidity than either SWL or URS ^[9–10], which has been reported in up to 83 % of cases. Complications arise mainly from the percutaneous puncture, associated with bleeding secondary to renal parenchymal damage, and adjacent structures injuries, such as colon (0.8 %) and pleura (3.1 %) causing septicemia (4.7 %) ^[11].

The advances in flexible ureteroscopy and intracorporeal lithotripsy have revolutionized the treatment of intrarenal calculi. Current technology allows access to and treatment of calculi throughout the intrarenal calyceal system using a single procedure, with stone-free rates up to 88 %. The combination of current-generation flexible ureteroscopes and the holmium laser allows for excellent fragmentation rates in an outpatient procedure, with low postoperative complications.

Our study supports the finding that ureteroscopy with a ureteral access sheath can treat stones throughout the renal collecting system with a high success rate ^[12–13]. In this series, there were multiple patients with stones 3mm or less in size. It is not our practice to routinely treat single small stones <3mm in size, because the likelihood for spontaneous passage is up to 90 %, However, the patients in this series who had small stones had concurrent larger stones that prompted intervention. Our treatment approach was then to render the patient stone free during treatment, and we consequently did treat these smaller fragments. Furthermore, all patients in this series underwent a diagnostic second-look ureteroscopy and stent placement between procedures. The utility of this second procedure was based on previous reports of multiple or large intrarenal stones managed ureteroscopically [4, 13, 14].

Our results are comparable to those previously published, with an overall stone-free rate after a single procedure of 62.5 %. The combination of current generation flexible ureteroscopes and the holmium laser allows for excellent fragmentation rates in an outpatient procedure, with low postoperative complications [15]. Our study supports the usefulness of nitinol tipless stone baskets and ureteral access sheath to manage stones throughout the renal collecting system with a high success rate. Recent reports indicate that the overall complication rates of URS are between 6 % and 16 %^[12,16]. Our overall complication rate was 15.2 % (seven patients): four patients with urinary tract infection who were treated with intravenous antibiotics; one patient developed pyelonephritis three day after his procedure, and was admitted to the hospital for intravenous antibiotics. He was fully recovered in 7 days. Two patients had significant bleeding, which resulted in poor visibility and led to abortion of the procedure. For one of them, transfusions were necessary. One patient underwent an uncomplicated second treatment 2 weeks later. Another patient had a successful operation 3 month later.

There are some limitations to this study. This is a retrospective review from a single institution. Our results are based on a relatively small sample size. However, this is the initial experience by a single surgeon.

5. Conclusions

Flexible ureteroscopy and lasertripsy for the treatment of multiple and bilateral renal calculi greater than 2cm in diameter is associated with high success rates. The presence of lower calyceal stones remains more difficult than in other anatomical positions but is still associated with a stone free rate of over 87.5 %. We believe fURS can become a first-line option of treatment for these patients.

References:

1.      Lingeman JE, Coury TA, Newman DM, Kahnoski RJ, Mertz JH, Mosbaugh PG, et al. Comparison of results and morbidity of percutaneous nephrostolithotomy and extracorporeal shock wave lithotripsy. J Urol 1987;138:485–90.

2.      Preminger GM, Assimos DG, Lingeman JE, Nakada SY, Pearle MS, Wolf Jr JS, et al. Chapter 1: AUA guideline on management of staghorn calculi: diagnosis and treatment recommendations. J Urol 2013;173:1991–2000.

3.      Landman J, Venkatesh R, Lee DI, Rehman J, Ragab M, Darcy M, et al. Combined percutaneous and retrograde approach to staghorn calculi with application of the ureteral access sheath to facilitate percutaneous nephrolithotomy. J Urol 2003;169:64–7.

4.      Breda A, Ogunyemi O, Leppert JT, Lam JS, Schulam PG. Flexible ureteroscopy and laser lithotripsy for single intrarenal stones 2 cm or greaterdis this the new frontier? J Urol 2008;179:981–4.

5.      那彦群，叶章群，孙颖浩，孙光等。第二章结石诊断和治疗。中国泌尿外科疾病诊断治疗指南2014；174–176。

6.      Pearle MS, Lingeman JE, Leiveillee R, et al. Prospective randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less. J Urol 2005;173:2005–2009.

7.      Gettman MT, Segura JW. Indications and outcomes of ureteroscopy for urinary stones. In: Stoller ML, Meng MV. Urinary Stone Disease. The Practical Guide to Medical and Surgical Management. Totowa, NJ: Humana Press, 2007, pp 581–584.

8.      Cass AS. Comparison of first generation (Dornier HM3) and second generation (Medstone STS) lithotriptors: Treatment results with 13,864 renal and ureteral calculi. J Urol 1995; 153:588–592.

9.      Preminger GM, Assimos DG, Lingeman JE, et al. Chapter 1: AUA guideline on management of staghorn calculi: Diagnosis and treatment recommendations. J Urol 2005;173:1991–2000.

10.  Lingeman JE, Siegel YI, Steele B, et al. Management of lower pole nephrolithiasis: A critical analysis. J Urol 1994;151:663– 667.

11.  Michel MS, Trojan L, Rassweiler JJ. Complications in percutaneous nephrolithotomy. Eur Urol 2007;51:899–906.

12.  Fabrizio MD, Behari A, Bagley DH. Ureteroscopic management of intrarenal calculi. J Urol 1998;159:1139–43.

13.  Grasso M. Experience with the holmium laser as an endoscopic lithotrite. Urology 1996;48:199–206.

14.  Preminger GM. Management of lower pole renal calculi: shock wave lithotripsy versus percutaneous nephrolithotomy versus flexible ureteroscopy. Urol Res 2006; 34:108–11.

15.  Stav K, Cooper A, Zisman A, Leibovici D, Lindner A, Siegel YI. Retrograde intrarenal lithotripsy outcome after failure of shock wave lithotripsy. J Urol 2003;170:2198–201.

16.  Stav K, Cooper A, Zisman A, et al. Retrograde intrarenal lithotripsy outcome after failure of shock wave lithotripsy. J Urol 2003;170:2198–2201.