World J Urol DOI 10.1007/s00345-014-1438-7
ORIGINAL ARTICLE
Comparison of treatment outcomes according to output voltage during shockwave lithotripsy for ureteral calculi: a prospective randomized multicenter study Jinsung Park · Hong‑Wook Kim · Sungwoo Hong · Hee Jo Yang · Hong Chung
Received: 18 August 2014 / Accepted: 1 November 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose To investigate the effect of fixed versus escalating voltage during SWL on treatment outcomes in patients with ureteral calculi (UC). Methods A prospective, randomized, multicenter trial was conducted on 120 patients who were diagnosed with a single radiopaque UC. The patients were randomized into group C (n = 60, constant 13 kV, 3,000 shock wave, 2 Hz) or group E (n = 60, 11.4–12.0–13 kV per 1,000 shock waves, 2 Hz). They were evaluated by plain abdominal radiography and urinalysis at 1 week after a single session of SWL, and repeat SWL was performed if needed. The primary endpoint was stone-free rate at 1 week (SFR1) Electronic supplementary material The online version of this article (doi:10.1007/s00345-014-1438-7) contains supplementary material, which is available to authorized users. J. Park Department of Urology, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Repubic of Korea H.‑W. Kim Department of Urology, Konyang University College of Medicine, Daejeon, Repubic of Korea S. Hong Department of Urology, Dankook University College of Medicine, Cheonan, Repubic of Korea H. J. Yang Department of Urology, Soonchunhyang University Cheonan Hospital, Cheonan, Repubic of Korea H. Chung (*) Department of Urology, School of Medicine, Konkuk University, 82 Gugwon‑daero, Chungju, Chungbuk 380‑704, Republic of Korea e-mail: [email protected]
after SWL. Secondary endpoints were post-SWL visual pain score (VPS), oral analgesic requirements during 1 week, and cumulative SFRs after the second and third sessions of SWL. Results Groups C and E were well balanced in terms of baseline patients and stone characteristics, including preSWL VPS, stone location, and stone size (6.24 ± 1.92 vs. 6.30 ± 2.13 mm). SFR1s were not significantly different between groups C and E (60.0 vs. 68.3 %, p = 0.447). Analyses stratified by stone size ( 1.8 mg/dl), (7) ureteral strictures, (8) severe hydronephrosis on imaging studies, (9) a past history of cystine stones, and (10) ureteral stent insertion before SWL due to colic. At enrollment, all patients were assessed by plain abdominal radiography (KUB) and intravenous pyelography or noncontrast CT to evaluate stone size, stone location, and the degree of hydronephrosis. Stone size was determined on the basis of the greatest diameter on KUB after magnifying 3–4 times on a picture-archiving communication system [14]. Stone location was classified as proximal (from the ureteropelvic junction to the upper border of pelvic bone), mid (ureter on pelvic bone) or distal (from the lower border of pelvic bone to the ureterovesical junction). Patients were asked about baseline visual pain score (VPS).
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World J Urol
In situ, SWL was performed using the Sonolith® Praktis (EDAP TMS, Vaulx-en-Velin, France) as an outpatient procedure. Ultrasonography gel was used as a SWL coupling agent. After gradual power increase during initial 100 shockwaves, patients were randomized (1:1 ratio) to one of the two groups: group C (constant, 13 kV, 3,000 shocks, 2 Hz) and group E (escalating, 11.4–12.0–13 kV per 1,000 shocks, 2 Hz). A predefined randomization sequence was created by a computer random number generator. During SWL, stone localization was rechecked every 250 shocks under fluoroscopy to ensure proper targeting. After SWL, patients were asked about postSWL VPS. At discharge, all patients were instructed to drink 2 L of water daily and to take an oral painkiller (acetaminophen and tramadol, Ultracet® ER) on demand. Since tamsulosin is reported to be beneficial for stone expulsion after SWL [15, 16], 0.2 mg of tamsulosin once a day was administered to all patients as discharge medication. Patients were evaluated on KUB and urinalysis at 1 week after a single session of SWL and asked to complete a specifically validated questionnaire [2] regarding oral analgesic requirements and their symptoms. In some patients who had neither symptom nor visible stone on KUB but had hematuria on urinalysis, final noncontrast CT was taken to confirm stone passage. If residual stones were observed at followup, repeat SWL was considered the first salvage treatment on the basis of patients’ symptoms and residual stone sizes. Patients with persistent severe symptoms, such as intractable pain, nausea, vomiting, or voiding symptoms, were given the opportunity to seek other active treatment (i.e., ureteroscopy) or ureteral stent insertion, some of whom underwent such auxiliary procedures at will. Outcomes analysis and sample size The primary endpoint was stone-free rate (SFR) at 1 week after SWL (SFR1). In our study, success was defined as no visible stone at follow-up imaging studies, and clinically insignificant residual fragments were regarded as failure. Secondary endpoints were post-SWL VPS, oral analgesic requirements for 1 week, and cumulative SFRs after the second and third sessions of SWL. Complications after SWL were also compared between the two groups. Primary outcome analyses and cumulative SFRs were based on the intent-to-treat population, namely, patients who had baseline assessments and were randomized. From previous studies on renal calculi [10, 11], escalating voltage resulted in an absolute increase in SFR by 30 %, compared to fixed voltage. We hypothesized that escalating voltage for UC would be associated with the same degree of benefit (approximately 30 %) as for renal calculi (group C: 50 % vs. group E: 80 %). Based on this assumption and a two-tailed α-level of 0.05 with 80 % power, the required number of patients was calculated to be
World J Urol Table 1 Baseline patient and stone characteristics Age (year), mean ± SD Sex Male, n (%) Female, n (%) Body mass index (kg/m2), mean ± SD Past stone history No, n (%) Yes, n (%) Baseline VPS, mean ± SD Stone size (mm), mean ± SD Range/median (mm) Stone site Right, n (%)
Group C = constant power, Group E = increasing power VPS visual pain score, SD standard deviation
Left, n (%) Stone location Proximal ureter Mid ureter Distal ureter Hydronephrosis None Mild Moderate
44. Considering a possible dropout rate of 10 % and a randomization block size of 4, we enrolled at least 104 patients (52 per group). To compare the groups, Fisher’s exact test was used with categorical variables and Student’s t test was used with continuous variables. All statistical analyses were twosided with p
ORIGINAL ARTICLE
Comparison of treatment outcomes according to output voltage during shockwave lithotripsy for ureteral calculi: a prospective randomized multicenter study Jinsung Park · Hong‑Wook Kim · Sungwoo Hong · Hee Jo Yang · Hong Chung
Received: 18 August 2014 / Accepted: 1 November 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose To investigate the effect of fixed versus escalating voltage during SWL on treatment outcomes in patients with ureteral calculi (UC). Methods A prospective, randomized, multicenter trial was conducted on 120 patients who were diagnosed with a single radiopaque UC. The patients were randomized into group C (n = 60, constant 13 kV, 3,000 shock wave, 2 Hz) or group E (n = 60, 11.4–12.0–13 kV per 1,000 shock waves, 2 Hz). They were evaluated by plain abdominal radiography and urinalysis at 1 week after a single session of SWL, and repeat SWL was performed if needed. The primary endpoint was stone-free rate at 1 week (SFR1) Electronic supplementary material The online version of this article (doi:10.1007/s00345-014-1438-7) contains supplementary material, which is available to authorized users. J. Park Department of Urology, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Repubic of Korea H.‑W. Kim Department of Urology, Konyang University College of Medicine, Daejeon, Repubic of Korea S. Hong Department of Urology, Dankook University College of Medicine, Cheonan, Repubic of Korea H. J. Yang Department of Urology, Soonchunhyang University Cheonan Hospital, Cheonan, Repubic of Korea H. Chung (*) Department of Urology, School of Medicine, Konkuk University, 82 Gugwon‑daero, Chungju, Chungbuk 380‑704, Republic of Korea e-mail: [email protected]
after SWL. Secondary endpoints were post-SWL visual pain score (VPS), oral analgesic requirements during 1 week, and cumulative SFRs after the second and third sessions of SWL. Results Groups C and E were well balanced in terms of baseline patients and stone characteristics, including preSWL VPS, stone location, and stone size (6.24 ± 1.92 vs. 6.30 ± 2.13 mm). SFR1s were not significantly different between groups C and E (60.0 vs. 68.3 %, p = 0.447). Analyses stratified by stone size ( 1.8 mg/dl), (7) ureteral strictures, (8) severe hydronephrosis on imaging studies, (9) a past history of cystine stones, and (10) ureteral stent insertion before SWL due to colic. At enrollment, all patients were assessed by plain abdominal radiography (KUB) and intravenous pyelography or noncontrast CT to evaluate stone size, stone location, and the degree of hydronephrosis. Stone size was determined on the basis of the greatest diameter on KUB after magnifying 3–4 times on a picture-archiving communication system [14]. Stone location was classified as proximal (from the ureteropelvic junction to the upper border of pelvic bone), mid (ureter on pelvic bone) or distal (from the lower border of pelvic bone to the ureterovesical junction). Patients were asked about baseline visual pain score (VPS).
13
World J Urol
In situ, SWL was performed using the Sonolith® Praktis (EDAP TMS, Vaulx-en-Velin, France) as an outpatient procedure. Ultrasonography gel was used as a SWL coupling agent. After gradual power increase during initial 100 shockwaves, patients were randomized (1:1 ratio) to one of the two groups: group C (constant, 13 kV, 3,000 shocks, 2 Hz) and group E (escalating, 11.4–12.0–13 kV per 1,000 shocks, 2 Hz). A predefined randomization sequence was created by a computer random number generator. During SWL, stone localization was rechecked every 250 shocks under fluoroscopy to ensure proper targeting. After SWL, patients were asked about postSWL VPS. At discharge, all patients were instructed to drink 2 L of water daily and to take an oral painkiller (acetaminophen and tramadol, Ultracet® ER) on demand. Since tamsulosin is reported to be beneficial for stone expulsion after SWL [15, 16], 0.2 mg of tamsulosin once a day was administered to all patients as discharge medication. Patients were evaluated on KUB and urinalysis at 1 week after a single session of SWL and asked to complete a specifically validated questionnaire [2] regarding oral analgesic requirements and their symptoms. In some patients who had neither symptom nor visible stone on KUB but had hematuria on urinalysis, final noncontrast CT was taken to confirm stone passage. If residual stones were observed at followup, repeat SWL was considered the first salvage treatment on the basis of patients’ symptoms and residual stone sizes. Patients with persistent severe symptoms, such as intractable pain, nausea, vomiting, or voiding symptoms, were given the opportunity to seek other active treatment (i.e., ureteroscopy) or ureteral stent insertion, some of whom underwent such auxiliary procedures at will. Outcomes analysis and sample size The primary endpoint was stone-free rate (SFR) at 1 week after SWL (SFR1). In our study, success was defined as no visible stone at follow-up imaging studies, and clinically insignificant residual fragments were regarded as failure. Secondary endpoints were post-SWL VPS, oral analgesic requirements for 1 week, and cumulative SFRs after the second and third sessions of SWL. Complications after SWL were also compared between the two groups. Primary outcome analyses and cumulative SFRs were based on the intent-to-treat population, namely, patients who had baseline assessments and were randomized. From previous studies on renal calculi [10, 11], escalating voltage resulted in an absolute increase in SFR by 30 %, compared to fixed voltage. We hypothesized that escalating voltage for UC would be associated with the same degree of benefit (approximately 30 %) as for renal calculi (group C: 50 % vs. group E: 80 %). Based on this assumption and a two-tailed α-level of 0.05 with 80 % power, the required number of patients was calculated to be
World J Urol Table 1 Baseline patient and stone characteristics Age (year), mean ± SD Sex Male, n (%) Female, n (%) Body mass index (kg/m2), mean ± SD Past stone history No, n (%) Yes, n (%) Baseline VPS, mean ± SD Stone size (mm), mean ± SD Range/median (mm) Stone site Right, n (%)
Group C = constant power, Group E = increasing power VPS visual pain score, SD standard deviation
Left, n (%) Stone location Proximal ureter Mid ureter Distal ureter Hydronephrosis None Mild Moderate
44. Considering a possible dropout rate of 10 % and a randomization block size of 4, we enrolled at least 104 patients (52 per group). To compare the groups, Fisher’s exact test was used with categorical variables and Student’s t test was used with continuous variables. All statistical analyses were twosided with p
