World J Urol DOI 10.1007/s00345-015-1585-5

ORIGINAL ARTICLE

Ultra‑mini PCNL versus flexible ureteroscopy: a matched analysis of analgesic consumption and treatment‑related patient satisfaction in patients with renal stones 10–35 mm Konrad Wilhelm1   · Simon Hein1 · Fabian Adams1 · Daniel Schlager1 · Arkadiusz Miernik1 · Martin Schoenthaler1 

Received: 10 March 2015 / Accepted: 2 May 2015 © Springer-Verlag Berlin Heidelberg 2015

Abstract  Purpose  To compare ultra-mini PCNL (UMP) and flexible ureteroscopy (fURS) for the treatment of medium- to large-sized renal stones with a focus on patients’ postsurgical cumulative analgesic consumption and treatmentrelated satisfaction. Methods  Twenty-five patients treated by UMP between April 2013 and October 2014 were matched to data of 25 fURS patients from an existing database. Clinical outcome parameters were recorded prospectively. Postoperative analgesic consumption was assessed using the Cumulative Analgesic Consumption Score (CACS), and satisfaction was measured with the Freiburg Index of Patient Satisfaction (FIPS) questionnaire. Results  Perioperative outcome parameters showed no significant differences except for mean operating times (fURS 98.52 min, UMP 130.12 min [p = 0.002]) and hospital stay (fURS 67.2 h, UMP 91.5 h [p = 0.04]). Primary stone-free rate was 96 % in fURS and 92 % in UMP. Complications Clavien grade 2 or 3 occurred in 16 % of UMP patients and in 4 % of fURS patients. Postsurgical cumulative analgesic consumption was almost identical in both groups with CACSs of 6.96 (0–15) for fURS and 6.8 (0–23) for UMP. Patients’ satisfaction was high in both techniques: FIPS score in fURS 1.67 (1–3) and 1.73 (1–4) in UMP (scale 1–6). Conclusions  Treatment of medium- to large-sized renal stones is safe and highly effective by both UMP and fURS.

* Konrad Wilhelm konrad.wilhelm@uniklinik‑freiburg.de 1



Department of Surgery, Clinic for Urology, University Medical Centre Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany

Moreover, both treatments yield comparable postsurgical analgesic requirements and high patient satisfaction scores. Patient-related factors (anatomical and stone related) and availability of technical equipment and surgical expertise appear to be the most important determining factors in treatment planning. Keywords  Ultra-mini PCNL · Percutaneous nephrolithotomy · Ureteroscopy · URS · RIRS · Urolithiasis · Pain · Analgesic consumption · Patient satisfaction Abbreviations CACS Cumulative Analgesic Consumption Score CRO Clinical-reported outcome EbM Evidence-based medicine FIPS Freiburg Index for Patient Satisfaction HRQol Health-related quality of life PRO Patient-reported outcome RIRS Retrograde intrarenal surgery fURS Flexible ureterorenoscopy UMP Ultra-mini PCNL

Introduction Common treatment options for renal stones include shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS)/flexible ureteroscopy (fURS) [1]. Both PCNL and URS have undergone tremendous technical evolution due to the availability of ever smaller optical systems and more sophisticated endoscopes and lithotripsy sources. Miniaturization of PCNL systems aims at lowering surgical invasiveness and complication rates [2]. Diameters of up-to-date PCNL

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systems have been reduced to 11 F or 13 F (Ultra-mini PCNL, UMP) or even 4.8 F (Microperc) [3, 4]. The decision on a chosen treatment option is generally based on patient and stone characteristics such as body mass index and size, number or location of stones or availability of technical equipment and surgical expertise. Common outcome parameters include stone-free rates and complications. Available data demonstrate comparable efficacy and complication rates of UMP and fURS in the treatment of medium-sized renal stones [5]. However, the principles of evidence-based medicine (EbM) call for the consideration of both clinical-reported outcome (CRO) parameters and patient-reported outcomes (PROs) [6]. In stone treatment, pain scores and patient satisfaction may offer additional information on the patient’s well-being. Since there is no general agreement concerning the best method of assessing pain scores, analgesic consumption may be more suitable as a surrogate parameter for surgical invasiveness and postoperative pain [7, 8]. Patient satisfaction (PS) is a PRO highly relevant as a specific parameter of health-related quality of life (HRQoL). In this study, we compared matched groups of patients treated by UMP or fURS using two validated scores on postsurgical analgesic consumption (Cumulative Analgesic Consumption Score, CACS) and treatment-related patient satisfaction (Freiburg Index of Patient Satisfaction, FIPS), both of which have been developed and published by our group [8, 9].

UMP was performed in prone position. Operating times included the initial placement of a ureteral catheter in lithotomy position and repositioning of the patient. In ureteroscopy, operating time was recorded from first passage of the urethra to insertion of a urethral catheter by the end of the procedure. Ancillary procedures included (elective) pre- and/or postoperative DJ stenting (performed in deep sedation) or nephrostomy tubing (performed in local anesthesia). Procedures performed due to renal colic and/or hydronephrosis prior to definite stone treatment were not included. Postoperative analgesic requirement was measured on the day of surgery and postoperative days 1 and 2 using the CACS [8]. The score includes the type of medication according to the WHO relief ladder (1 = non-opioid, 2 = opioid for mild to moderate pain, 3 = opioid for moderate to severe pain) and the frequency of administration of “adequate doses” to achieve sufficient pain relief (reduction of NRS pain scores to values ≤3) (Fig. 1). Treatment-related patient satisfaction was evaluated using the Freiburg Index of Patient Satisfaction (FIPS) [9]. This questionnaire includes five questions with scorings from 1 (excellent) to 6 (very poor). Patients were asked to answer the questionnaire 3 months after the procedure (Fig. 2). Statistic evaluation was performed with IBM SPSS Statistics version 22 using Student’s t test for the comparison of the two interventional groups and using Spearman’s rho test for correlations between different values.

Materials and methods

Surgical techniques

Twenty-five patients treated by UMP between April 2013 and October 2014 were matched to data of 25 fURS patients from an existing database. All data were collected prospectively after ethical approval by the local ethic committee and informed consent. Patients were matched according to cumulative stone size (maximum difference within a pair ±1 mm), number of stones (±1) and patient age (±10 years). Acquisition of data was based on the recommendations of a recent consensus publication on outcome definitions in percutaneous stone surgery [10]. Primary stone-free rate (SFR) was defined as the absence of significant residual fragments >4 mm as assessed by endoscopic inspection and immediate postoperative ultrasound, or low-dose CT 4–8 weeks after the procedure (in cases of suspected residual fragments). Complications were classified according to the modified Clavien-Dindo score for PCNL procedures [11].

Both UMP and RIRS were performed under general anesthesia and antibiotic prophylaxis with ciprofloxacin or a supplement in case of fluoroquinolone allergy.

Fig. 1  Cumulative Analgesic Consumption Score (CACS) [8]

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UMP After transurethral placement of a 5-F occlusion catheter in lithotomy position, the patient is turned to a prone position. Puncture of the pelvicaliceal system is performed under ultrasound and fluoroscopy guidance. After the placement of a hydrophilic safety guide wire, a 7-F duallumen angiography catheter and a second guide wire are inserted. Tract dilation is restricted to 14 F and performed with 10-F and 14-F PTFE dilators. After the placement of the 13-F UMP sheath and nephroscope, the stone is fragmented using a holmium laser. Fragments and blood clots are washed out and/or actively removed using a nitinol

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Fig. 2  Translated version of the validated German version of the Freiburg Index of Patient Satisfaction (FIPS) [9]

basket. The procedure is finished with the placement of a 10-F nephrostomy. The nephrostomy is removed after the confirmation of a free ureter passage by antegrade ureterography (24–36 h after UMP).

used (to be extracted on the second postoperative day by pulling on the string).

Results RIRS All patients have been pre-stented with a 5-F DJ stent for 8–16 days [patients with previous DJ stenting to treat renal colic and/or hydronephrosis in proximal ureteral stones (push back of stones into the renal pelvis) or patients receiving elective stenting to prepare fURS]. Flexible ureteroscopy is started with cystoscopic displacement of the DJ catheter and the insertion of a hydrophilic safety wire. Intraureteral lesions, stones or insufficient ureter dilation is excluded using a semirigid ureteroscope. A second guide wire is inserted, and a 14-/16-F ureteral access sheath (UAS) is pushed up to the proximal ureter. A flexible ureteroscope is used for the complete inspection of the pelvicaliceal system. Stones are fragmented with a holmium laser, and complete removal of fragments is performed using a nitinol basket and postoperative stenting if appropriate according to PULS recommendations [12]. In cases of intended short-term postoperative stenting (2 days), DJ stents with an attached string are

Twenty-five nephrolithiasis patients treated by UMP were matched to 25 patients treated with fURS. Main patient characteristics and operative outcome parameters are shown in Table 1. Adequate matching of the patients was confirmed by minor insignificant differences regarding age, body mass index, cumulative stone size, number of stones or ASA classification. One patient in the UMP group and two patients in the RIRS group had aspirin 100 mg treatment. Primary stone-free rate was excellent for both treatment modalities. SFR was 100 % in both groups after staged procedures in three patients (second URS in two UMP and one URS patients). Operating times and postsurgical hospital stay were significantly longer in the UMP group. No patient needed a blood transfusion, and no urinary leakage was observed in either group. No patient developed persistent hydronephrosis during a minimal follow-up period of 2 months for the UMP group and a longer follow-up for the fURS group.

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Table 1  Patient and operative outcome parameters

Patient characteristics  Sex (m/f)  Mean age (years, range)  Mean body mass index (kg/m2, range) Stone characteristics  Mean cumulative stone size (mm, range)  Mean number of stones (range) Operative data and outcome  Mean operating time (min, range)  Mean hospital stay (h, range)  Stone-free rate (%)  Complications Clavien 2 or 3 (%)

fURS (n = 25)

UMP (n = 25)

p

19/6 51.36 (19–77) 28.41 (18.4–38.57)

15/10 51.56 (15–75) 29.54 (18.75–42.94)

n.a. 0.964 0.485

19.20 (10–35) 1.64 (1–3)

19.28 (10–35) 1.38 (1–3)

0.968 0.176

98.52 (40–155) 67.20 (48–312) 96 4

130.12 (48–205) 91.52 (48–144) 92 16

0.002* 0.041* 0.561 0.164

 Mean number of ancillary procedures (overall) (n, per patient)

1.28 (1–2)

1.08 (0–2)

0.068

 Mean ancillary procedures (additional outpatient procedures) (n, per patient)

0.76 (0–1)

0.08 (0–1)

0.000*

 Mean CACS (range)

6.96 (0–15)

6.80 (0–23)

0.917

 Mean FIPS (range)

1.67 (1–3)

1.73 (1–4)

0.807

* p