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Keywords:

  • renal calculi;
  • retrograde ureteropyeloscopy;
  • holmium laser;
  • lithotripsy

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

Objective To assess the efficacy and safety of the retrograde ureteropyeloscopic holmium laser for treating renal stones that are too large to treat with extracorporeal shock wave lithotripsy (ESWL).

Patients and methods Thirty patients (22 men and eight women, mean age 43 years, range 18–62) with a renal stone burden of > 2 cm were selected for laser treatment. The stones were in the renal pelvis in 16 patients, lower calyx in five, middle calyx in two, upper calyx in one and multiple pelvic and calyceal in six. Lithotripsy was undertaken using a holmium laser through 550 µm and 200 µm laser fibres passed through a semi-rigid fibre-optic long ureteroscope or the actively deflectable flexible ureteropyeloscope, respectively. Success was defined as total fragmentation of the stone to < 2 mm in diameter and/or clear imaging on renal ultrasonography and plain films within the 3-month follow-up. Patients in whom the treatment failed received either alternative therapy or complementary ESWL.

Results Endoscopic access and complete stone fragmentation was achieved in 23 of the 30 patients (77%). The treatment failed in seven patients because of poor visualization, the initial presence of stones in, or migration of their large fragments to, an inaccessible calyx. There were no major intraoperative complications. Minor complications after treatment included haematuria that persisted for 2 days in one patient and high-grade fever in two patients; all were treated conservatively.

Conclusion Large renal calculi that are not amenable to ESWL monotherapy can be safely and effectively treated with a retrograde endoscopic technique that seems to compete well with the more invasive percutaneous or open surgical manoeuvres.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

The treatment of renal calculi includes ESWL to fragment stones into more easily passable pieces, percutaneous techniques to extract and fragment stones under direct vision, or open surgery. The indications for ESWL have been refined such that a renal stone burden of > 2 cm is now considered to be best treated using endoscopic techniques [1]. Other anatomical variants can preclude successful ESWL [2]; moreover, bleeding diathesis or kidney malposition may hinder ESWL or percutaneous access. Percutaneous nephrolithotomy (PCNL) has an excellent success rate in clearing stone burden, but it is invasive, with a small but significant rate of major complications.

The retrograde application of the ureterorenoscope in treating large renal calculi not amenable to ESWL monotherapy is not new. Huffman et al.[3] described the treatment of large ureteric and pelvic stones with a rigid rod-lens ureteroscope and a hollow-core ultrasonic lithotripter. However, their success was limited to treating only stones that could be accessed with a rigid instrument. With the development of semi-rigid, fibre-optic based ureteroscopes and actively deflectable, flexible ureterorenoscopes, the entire upper urinary tract is now amenable to retrograde endoscopic lithotripsy [4–7], since the endoscopes were miniaturized and lithotrites have become more powerful and precise. For example, the holmium laser not only fragments calculi but also vaporizes and pulverizes stones to a ‘dust’ that can be passed spontaneously [8,9].

We assessed the application of current endoscopic techniques and the holmium laser to treat large renal calculi not amenable to ESWL monotherapy, as they represent a less invasive means to avoid the risk of more invasive percutaneous approaches or open surgery.

Patients and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

The study included 30 patients (22 men and eight women, mean age 43 years, range 18–62, with 40 stones). All patients with a renal stone burden of > 2 cm during the study period (March 1999 to September 2000) were eligible for the procedure. Patients were excluded if they refused the procedure or had an extremely dilated pelvicalyceal system. The evaluation before treatment included standard radiography and abdominal ultrasonography, and urine analysis with antibiotic culture and sensitivity tests to render the urinary tract sterile before the procedure; Table 1 shows the location and number of the stones.

Table 1.  Success in relation to stone number and location and success rate in relation to stone burden
Site of renal stonesNo. of patientsNo. of stonesSuccess, no. of patients
Pelvic161614
Lower calyceal 511 3
Middle calyceal 2 2 2
Upper calyceal 1 1 1
Mixed pelvic and calyceal 610 3
Total304023

With the patient in the lithotomy position, under general or regional anaesthesia, a guidewire was placed into the upper urinary tract using the standard rigid cystoscope under fluoroscopic control. A 10 F double-lumen catheter was used to dilate the intramural ureter and to obtain a retrograde ureteropyelogram (to act as a ‘road map’) by injecting contrast material into the second channel. An additional 0.9 mm guidewire was also inserted, as the working guidewire over which the flexible ureteroscope could be passed into the upper urinary tract when indicated.

The long semi-rigid fibre-optic ureteropyeloscope (7.5–10 F) was used for all patients with pelvic stones. The actively deflectable, flexible ureteroscope (7.5 F) was used for the calyceal stones and for migrated large fragments of the pelvic stones. Sterile saline irrigant was used in all patients. For endoscopic lithotripsy the holmium laser was directed through a 550 µm laser fibre when the semi-rigid ureteroscope was used, and a 200 µm laser fibre when the flexible ureteroscope was used. The laser energy setting varied depending on stone composition (mean 1.0 J) at a frequency of 5–20 Hz, to obtain fragments of leqslant R: less-than-or-eq, slant2 mm in diameter and a fine ‘dust’.

For pelvic stones fragmentation was started inferiorly on one side of the stone, proceeding superiorly until a tunnel was formed in the stone, allowing passage of the ureteroscope beside the stone to its superior border. Fragmentation was then completed from the superior part moving inferiorly, to minimize the chance of migration of large stone fragments into the calyces. If there were large pieces of debris after fragmentation, two retrograde ureteric catheters were inserted into the collecting system to institute continuous irrigation. The inflow was through a 5 F catheter placed in the most dependent calyx containing the debris, and the outflow through a 6 F catheter positioned in the upper calyx. The irrigant was saline with gentamicin 80 mg/L at a rate of 100 mL/h. The height of the head of the irrigant container was fixed at 15 cm above the symphysis pubis. The ureteric stent was placed for 5–7 days after treatment; patients not requiring irrigation after treatment and those scheduled to undergo ESWL were left with JJ stents. All patients received prophylactic parenteral antibiotic for 3 days (against intraoperative infection which is common in developing countries, especially in bilharzial patients) then substituted with an oral antimicrobial for an extra 4 days. No patient underwent more than one session of retrograde ureteroscopy because they refused to accept more than one anaesthetic session.

All patients had plain abdominal films taken immediately after treatment before leaving theatre, and plain films and abdominal ultrasonography 1 month afterward to exclude ‘silent’ obstruction and to quantify the residual stone burden. Depending on these results other images were obtained as required. Success was defined as the total fragmentation of the stone to a dust of < 2 mm in diameter or clear imaging (stone-free) on subsequent radiographs. Patients requiring complementary ESWL were not considered to be successful.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

In all, 30 retrograde ureteropyeloscopic procedures were undertaken to treat the 40 stones in the 30 patients (Table 1); the procedure was successful in 23 (77%). There was a close association between stone size, success and operative duration. A stone burden of 2–3 cm in 23 patients required a mean (range) treatment duration of 70 (55–85) min and was successful in 20; in seven patients with a burden of > 3 cm, the treatment took 135 (75–160) min and was successful in three. Thus the smaller the burden the greater the success and the less time required for treatment.

Failure with two pelvic stones resulted from the migration of large stone fragments into inaccessible calyces in one and poor visualization in the other. The two failures with calyceal stones resulted from an inability to access these calyces. The remaining three failures were in patients with multiple pelvic and calyceal stones.

Conversion to a standard percutaneous technique was decided early in the procedure in three patients, of whom one had a large pelvic stone and two had multiple pelvic and calyceal stones. The remaining four patients in whom the retrograde ureteroscopic procedure failed were scheduled to undergo complementary ESWL (Table 1).

Nineteen patients were assessed by late follow-up imaging, with plain films and post-hydration abdominal ultrasonography (at 6–12 months); 17 of these patients remained completely clear, while two had new stone growth. These two patients were known stone-formers and had undergone several previous therapeutic procedures.

There were no major intraoperative complications and none related to the continuous irrigation with gentamicin solution. There were only two early complications after treatment, i.e. haematuria that persisted for 2 days in one patient and high-grade fever in two, all treated conservatively. There were no long-term complications and specifically no ureteric or renal obstruction.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

The current treatment options for upper urinary tract calculi include ESWL, percutaneous antegrade endoscopic lithotripsy and retrograde ureteroscopic therapy [1]. ESWL represents the first-line therapy for most moderate-sized intrarenal stones of < 2 cm. Larger stone burdens necessitate auxiliary measures, including PCNL or ureteric stenting.

Innovations in endoscopes and endoscopic lithotrites allow not only the entire intrarenal collecting system to be accessed retrogradely, but also the treatment of large stone burdens previously reserved for primary percutaneous techniques. The holmium laser is a significant improvement from previous technology such that stone burdens of all compositions and sizes can be fragmented into dust and small debris [8,10]. Improvements in endoscope design, and specifically the addition of the small diameter, actively deflectable flexible ureteropyeloscope, facilitated complete upper urinary tract access to almost all calyces [11]. The combination of the flexible ureteroscope and the 200 µm holmium laser fibre allows the treatment of all intrarenal calculi.

Transurethral ureteroscopic treatment of large renal calculi is not new; in 1994, Dretler [12] reported treating eight patients with staghorn stones using staged flexible ureteroscopic pulsed-dye laser lithotripsy and subsequent ESWL for small residual stones. In addition, other studies of retrograde intrarenal endoscopic lithotripsy have reported small cohorts of ureteroscopically treated large intrarenal calculi [1,6–9]. The present study reports a moderate series of patients with a large renal stone burden treated ureteroscopically with the semi-rigid fibre-optic ureterorenoscope and flexible ureterorenoscope.

Using the holmium laser, the efficacy of stone fragmentation and clearance is not dependent on stone composition; this contrasts with other endoscopic lithotripsy techniques not using the holmium laser. The present initial success rate was 77%, and similar to that reported by Grasso et al.[13]. However, Elashry et al.[14] reported a success rate of 92% when intrarenal calculi were treated with the flexible ureteroscope and 1.9 F electrohydraulic lithotripsy probe. Moreover, Fabrizio et al.[15] reported on 100 patients who underwent retrograde endoscopy with the holmium laser or electrohydraulic lithotripsy probe, with an immediate success rate of 89%. The relatively low initial success rate in the present series may reflect the value of experience.

Failure to achieve complete success is inevitable with any new surgical technique, but such failure can be compensated by the minimal invasiveness. In the present series, the failure rate was similar to the 24% reported by Grasso et al.[13] after the first session of endoscopic lithotripsy in 51 patients treated with flexible ureteroscopy and the holmium laser.

In the present series, there were no complications arising from the continuous irrigation with gentamicin solution, in agreement with other reports [13,16], and few patients had persistent haematuria or high-grade fever, in contrast to reports by others [13,14,16].

The relative infrequency of the present procedure makes it difficult to attempt a cost analysis in one institution; multi-institutional studies are required. The procedure requires no more disposable items than are usually used in routine ureteroscopy or PCNL, but the requirement for a flexible deflectable ureterorenoscope, which is inherently fragile and easily malfunctions, may make the procedure costly. In the present series the deflectable ureterorenoscope was used in 18 patients, the remaining procedures using the semi-rigid fibre-optic ureterorenoscope. Only once did the flexible ureterorenoscope malfunction in the deflection mechanism.

In conclusion, retrograde ureteropyeloscopic renal stone treatment represents a minimally invasive alternative to PCNL and open surgery; it is safe and effective for treating large renal pelvic stones not amenable to less invasive techniques.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements

The authors thanks Prof Dr A. Elhaggagy, Chief of Urology Department, Faculty of Medicine, Assiut University for his valuable support and advice.

References

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F.G. El-Anany, MD, Assistant Professor.

H.M. Hammouda, MD, Assistant Professor.

H.A. Maghraby, MD, Assistant Professor.

M.A. Elakkad, MD, Professor and Vice Dean.

Abbreviations
PCNL

percutaneous nephrolithotomy.