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Trauma/Reconstruction/Diversion Assessing the Impact of Ureteral Stent Design on Patient Comfort James E. Lingeman,*,† Glenn M. Preminger, Evan R. Goldfischer‡ and Amy E. Krambeck (The Comfort Study Team) From the Methodist Hospital Institute for Kidney Stone Disease (JEL, AEK), Indianapolis, Indiana, Division of Urology, Duke University (GMP), Durham, North Carolina, and Hudson Valley Urology Center (ERG), Poughkeepsie, New York Purpose: We assessed the near term comfort of newly designed ureteral study stents or marketed control stents, including Polaris™ and Percuflex® stents. Study stents had distal 6Fr pigtail ends with 3Fr or less loops. Decreased material in situ was hypothesized to enhance comfort. Usefulness of the patient self-administered Ureteral Stent Symptoms Questionnaire (Stone Management Unit, Southmead Hospital, United Kingdom) was assessed. Materials and Methods: This 4-arm multicenter study enrolled adults requiring retrograde unilateral ureteral stent placement for 4 to 28 days. Ureteral Stent Symptoms Questionnaire administration was done before placement (baseline), on day 4 after placement and on day 30 after removal. A total of 236 patients were randomized in a 1:1:1:1 ratio to the short loop tail stent (60), the long loop tail stent (59), the Percuflex Plus stent (64) and the Polaris stent (53). Results: Overall pain worsened from baseline to day 4 and improved from days 4 to 30. Mean pain medication use peaked for all stents on day 1 after placement. Common device related symptoms were mild or moderate in severity, including flank pain in 47 patients, hematuria in 39, dysuria in 34, frequent urination in 30 and urinary urgency in 27. Six patients experienced a total of 9 device related adverse events requiring hospitalization. All adverse events resolved, including most within 3 days of inpatient treatment. Conclusions: Although it was not statistically significant, patients stented with the short loop tail had lower questionnaire pain scores on day 4 after placement and lower pain medication use on day 1 after placement when pain peaked in all stent groups, suggesting that ureteral stent comfort, especially pain, may be improved by less material in situ. The Ureteral Stent Symptoms Questionnaire may be better suited for longer term comparisons in stented vs nonstented patients, rather than in this short-term ureteral stent trial. Abbreviations and Acronyms AE ⫽ adverse event LLT ⫽ long loop tail PC ⫽ Polaris stent PPC ⫽ Percuflex Plus stent SLT ⫽ short loop tail USSQ ⫽ Ureteric Stent Symptoms Questionnaire VAS ⫽ visual analog scale Submitted for publication October 9, 2008. Study received approval from local institutional review boards. * Correspondence: Methodist Hospital Institute for Kidney Stone Disease, 1801 Senate Blvd., Suite 220, Indianapolis, Indiana 46202 (telephone: 317-962-2485; FAX: 317-962-2893; e-mail: [email protected]). † Financial interest and/or other relationship with Lumenis, Boston Scientific, Olympus, Karl Storz Medical and Cook Urological. ‡ Financial interest and/or other relationship with Boston Scientific. Key Words: ureter, stents, pain, complications, questionnaires THE precise etiology of pain during ureteral stent indwell remains elusive. Previously groups have assessed the impact of ureteral stent composition, caliber, length and configuration on patient discomfort.1–5 With the introduction of USSQ in 2003 a standardized instrument became avail- able for use in clinical trials to evaluate patient comfort after stent placement. 6,7 USSQ validation in the United Kingdom was done in a clinical trial setting, comparing symptoms in stented and nonstented patients who were evaluated 1 and 4 weeks after stent placement, and 4 0022-5347/09/1816-2581/0 THE JOURNAL OF UROLOGY® Copyright © 2009 by AMERICAN UROLOGICAL ASSOCIATION Vol. 181, 2581-2587, June 2009 Printed in U.S.A. DOI:10.1016/j.juro.2009.02.019 www.jurology.com 2581 2582 URETERAL STENT DESIGN AND COMFORT weeks after stent removal. This timing was consistent with standard practice in the United Kingdom. Near term (less than 1 week) comfort was not assessed in the USSQ validation study. Until recently near term comfort had not been assessed in a large clinical population involving a comparison of multiple stent types. We examined the hypothesis that substituting the distal pigtail end of a ureteral stent with an SLT or LLT design would enhance patient comfort by decreasing mass and material in situ. USSQ was used in this study and we secondarily evaluated it as a tool for assessing stent discomfort. MATERIALS AND METHODS This was a prospective, 4-arm multicenter study comparing stent related comfort in patients 18 years old or older who had undergone uncomplicated ureteroscopy requiring retrograde unilateral placement of a ureteral stent for 4 to 28 days inclusive. Study exclusion criteria were active urinary tract infection, urinary malignancy, nonstone related pain or stricture, spinal cord injury, bilateral stent placement or chronic anti-inflammatory medication. Patients provided signed informed consent before study entry at study centers and the study was approved by local institutional review boards. The study was designed to compare differences in patient ureteral stent related comfort, as assessed by the patient self-administered USSQ. USSQ is the only standardized instrument available to assess patient comfort (pain and quality of life) after ureteral stent placement.6 – 8 Appropriate to anatomical differences, male and female versions of USSQ were administered. The timing of instrument administration involved certain time points, including baseline (immediately before stent placement), 4 days after stent placement and 30 ⫾ 5 days after stent removal. The Appendix lists USSQ components. Changes in the pain score were assessed between day 4, when peak pain was expected, and day 30, when patient comfort levels were expected to return to an almost normal level.9 Patients were randomized in a 1:1:1:1 ratio to receive 1 of 4 stents. All patients were blinded to the stent received. The 2 study stents were the SLT and LLT stents, and the 2 control stents were the PC and PPC stents. The proximal portions of all stents were configured in identical 6Fr pigtail designs of the same basic composition but they differed in the distal third portion. Control PC and PPC were standard double-pigtail designs, while SLT and LLT study stents had substitution of the distal pigtail ends with 2, 5 cm 3Fr or less loops (SLT) or 2, 8 cm 3Fr or less loops (LLT) (see figure). The distal ends of SLT and LLT stents each had 70% less mass by volume than a standard pigtail end. The length of stent placed was determined by patient height. During the postoperative period patients had unrestricted access to pain medications such as oxycodone or hydrocodone under principal investigator guidance. At discharge home the pain management regimen included 1 Study stents were substituted for control stent distal pigtail ends with 2, 5 cm 3Fr or less loops (SLT design) or 2, 8 cm 3Fr or less loops (LLT design). or 2 tablets of 325 mg/5 mg oxycodone or 500 mg/5 mg hydrocodone every 4 to 6 hours as needed for pain. To compare patient comfort during stent placement pairwise comparisons were made among stent groups. Comparisons were performed using multiple comparison tests at an overall 5% significance level. The 2-sided F-test was used to determine significant differences in USSQ scores or pain medication use among the 4 stent groups, followed by the Tukey HSD pairwise test when F-test p ⬍0.05. Additionally, a comparison was made of the pooled pair of study stents with the pooled pair of control stents. Statistical analysis was performed using SAS® software. RESULTS From April 2003 to February 2004, 236 patients were eligible for ureteral stent placement and were assigned randomly to 1 of the 4 stent groups, including 60 to the SLT group, 59 to the LLT group, 64 to the PPC group and 53 to the PC group. Since the study was stopped after interim analysis, an unequal number of patients were in each group. The 4 treatment groups were comparable demographically (table 1). A 17.7-year-old patient was enrolled in the study as an inadvertent protocol deviation. Table 2 lists surgical procedure details. Operative time and anesthesia type were not collected as part of the protocol. In 231 of 236 cases (97.9%) mean ⫾ SD device indwelling time was 4.1 ⫾ 1.99 days, including 4.0 ⫾ 0.13 days in 64 PPC, 4.0 ⫾ 0.44 days in 53 PC, 4.5 ⫾ 3.98 days in 57 LLT and 4.0 ⫾ 0.26 days in 57 SLT cases. In the remaining 5 of 236 patients (2.1%) a protocol deviation occurred due to AEs and the stents were removed before day 4, including in 1 URETERAL STENT DESIGN AND COMFORT 2583 Table 1. Patient characteristics in each treatment cohort PPC No. pts Age: No. pts Mean (range) No. sex (%): M F Wt: No. pts Mean lbs (range) Ht: No. pts Mean in (range) PC 64 64 50.48 38 26 (21.6–81.6) (59.4) (40.6) 64 196.32 (127.9–353.0) 64 67.32 (59.0–82.0) LLT Stent 53 59 53 50.33 (23.8–81.7) 59 46.57 34 19 34 25 (64.2) (35.8) 53 183.50 (95.0–341.0) 52 67.34 (60.0–74.0) patient each in the PC and SLT groups, and in 3 in the LLT group. Many device related AEs were expected side effects of ureteral stents. Tables 3 and 4 list procedure and device related AEs. Of device related AEs 86.5% were judged by the investigators to be mild or moderate in severity. Comparison of the overall AE rate among the 4 stent types, including 43.8% for PPC, 64.2% for PC, 52.5% for LLT and 40.0% for SLT, showed no statistical significance (p ⫽ 0.051). Comparison of the device related AE rate among the 4 stent types, including 37.5% for PPC, 49.1% for PC, 37.3% for LLT and 36.7% for SLT, was also not significant (p ⫽ 0.495). Six patients (2.5%), including 1, 4 and 1 with a SLT stent, LLT stent and PC, respectively, experienced a total of 9 device related AEs that led to hospitalization. These events were flank pain in 3 patients (3 events), stent migration in 1 (1 event), urinary tract infection in 2 (2 events), urosepsis and concurrent fever in 1 (2 events, respectively) and suicidal thoughts in 1 (1 event). All events resolved after hospitalization, including most within 3 days of inpatient treatment. In 10 patients, including 4, 4, 1 and 1 with LLT stent, SLT stent, PC and PPC, respectively, stents were removed due to AEs. Stents in 5 patients were removed within 4 days of placement, while in 4 the stents remained in place for 9 to 28 days. The duration of stenting in 1 patient was not recorded. AEs leading to stent removal were typically flank or suprapubic pain and urinary urgency or frequency. The patterns of change in overall USSQ comfort scores (combined body pain questions P3 to P9) were similar in all stent cohorts (table 5). Comparison of the individual USSQ components, body pain question P3 (VAS) and body pain questions P4 to P9 (kidney pain related to daily activity) again demonstrated no change from days 4 to 30 among the different stent types (p ⫽ 0.667 and 0.898, respec- SLT Stent 60 (17.7–85.0) (57.6) (42.4) 59 202.37 (101.0–389.0) 59 67.21 Totals (59.0–79.0) 60 53.65 37 23 236 (18.0–78.9) (61.7) (38.3) 60 190.90 (117.0–328.5) 60 68.03 (61.0–74.0) 236 50.27 (17.7–85.0) 143 93 (60.6) (39.4) 236 193.58 (95.0–389.0) 235 67.48 (59.0–82.0) tively). Overall patients experienced worsening of pain from baseline to day 4 (increasing USSQ score) and then improvement in pain from days 4 to 30 (decreasing USSQ score). Patients with an SLT stent had lower USSQ pain scores day 4 after placement. However, differences in pain scores among stent types and between stent groups (study vs control) at each time point were not statistically significant. In all stent groups more patients reported pain localized to the groin, bladder or flank areas, although no statistically significant differences were observed among the stents. Pain medication use was measured daily from baseline to day 4 (table 6). Mean use peaked in all stent groups on day 1 after placement and patients who received a SLT stent had the lowest mean use at this point. Mean pain tablet counts on days 2 and 3 were significantly higher in LLT cases than in others (Tukey HSD test p ⬍0.05), although mean use on day 4 was clinically and statistically the same as that of the other stents. Patients in the SLT and LLT groups experienced the largest percent decrease from peak use to day 4 (53% and 57%, respectively). DISCUSSION Multiple ureteral stent shapes, sizes, compositions (durometers) and designs have been studied to decrease patient discomfort during ureteral stent placement and indwelling time. However, the precise etiology of pain during ureteral stent indwelling remains elusive. Clinical evaluation of 2 investigational stents (SLT and LLT) and currently available double pigtail PC and PPC showed similar comfort and safety profiles. The absence of statistically significant differences between USSQ pain scores in patients with different stents may have been the result of several factors related to stent design, study design and the choice of USSQ as the instrument with which to measure near term comfort. 2584 URETERAL STENT DESIGN AND COMFORT Table 2. Surgical procedure in each patient cohort No. PPC (%) Overall Antibiotic regimen before procedure: 120 mg Gentamicin ⫹ ampicillin 120 mg Gentamicin, no ampicillin 400 mg Ciprofloxacin 1 gm Cefazolin Other Missing data Ureteroscopy purpose: Stone Diagnosis Other Ureteroscopy: Flexible Rigid Flexible ⫹ rigid Dilation: None Balloon Rigid Other Dilator size (Fr): 12 or Less Greater than 12–less than 18 18 or Greater Procedure sheath: Yes No Intracorporeal lithotripsy:* Not applicable Holmium laser Other Stone removal device:† Not applicable Stone basket Stone cone 3-Prong graspers Other Residual fragments: None visible 2 mm or Less Greater than 2 mm Foley catheter: Yes No Stent side: Lt Rt No. PC (%) No. LLT Stent (%) No. SLT Stent (%) Total No. (%) 64 53 59 60 236 20 (31.3) 8 (12.5) 3 (4.7) 26 (40.6) 6 (9.4) 1 (1.6) 17 (32.1) 6 (11.3) 2 (3.8) 22 (41.5) 6 (11.3) 0 20 (33.9) 5 (8.5) 5 (8.5) 22 (37.3) 5 (8.5) 2 (3.4) 19 (31.7) 4 (6.7) 3 (5.0) 31 (51.7) 3 (5.0) 0 76 (32.2) 23 (9.7) 13 (5.5) 101 (42.8) 20 (8.5) 3 (1.3) 60 (93.8) 4 (6.3) 0 49 (92.5) 3 (5.7) 1 (1.9) 58 (98.3) 1 (1.7) 0 55 (91.7) 5 (8.3) 0 222 (94.1) 13 (5.5) 1 (0.4) 24 (37.5) 27 (42.2) 13 (20.3) 23 (43.4) 21 (39.6) 9 (17.0) 25 (42.4) 27 (45.8) 7 (11.9) 28 (46.7) 26 (43.3) 6 (10.0) 100 (42.4) 101 (42.8) 35 (14.8) 45 (70.3) 9 (14.1) 4 (6.3) 6 (9.4) 41 (77.4) 4 (7.5) 6 (11.3) 2 (3.8) 48 (81.4) 0 7 (11.9) 4 (6.8) 42 (70.0) 5 (8.3) 8 (13.3) 5 (8.3) 176 (74.6) 18 (7.6) 25 (10.6) 17 (7.2) 9 (14.1) 4 (6.3) 6 (9.4) 6 (11.3) 3 (5.7) 3 (5.7) 7 (11.9) 4 (6.8) 0 10 (16.7) 7 (11.7) 1 (1.7) 32 (13.6) 18 (7.6) 10 (4.2) 32 (50.0) 32 (50.0) 23 (43.4) 29 (54.7) 24 (40.7) 35 (59.3) 25 (41.7) 35 (58.3) 104 (44.1) 131 (55.5) 21 (32.8) 43 (67.2) 0 21 (39.6) 31 (58.5) 1 (1.9) 21 (35.6) 38 (64.4) 0 26 (43.3) 33 (55.0) 1 (1.7) 89 (37.7) 145 (61.4) 2 (0.8) 27 (42.2) 33 (51.6) 2 (3.1) 1 (1.6) 1 (1.6) 26 (49.1) 24 (45.3) 1 (1.9) 2 (3.8) 0 20 (33.9) 34 (57.6) 2 (3.4) 2 (3.4) 1 (1.7) 21 (35.0) 35 (58.3) 2 (3.3) 0 2 (3.3) 94 (39.8) 126 (53.4) 7 (3.0) 5 (2.1) 4 (1.7) 34 (53.1) 30 (46.9) 0 28 (52.8) 23 (43.4) 2 (3.8) 34 (57.6) 24 (40.7) 1 (1.7) 33 (55.0) 25 (41.7) 0 129 (54.7) 102 (43.2) 3 (1.3) 11 (17.2) 53 (82.8) 6 (11.3) 47 (88.7) 3 (5.1) 56 (94.9) 3 (5.0) 57 (95.0) 23 (9.7) 213 (90.3) 20 (31.3) 21 (32.8) 19 (35.8) 13 (24.5) 21 (35.6) 13 (22.0) 18 (30.0) 19 (31.7) 78 (33.1) 66 (28.0) * Electrohydraulic, pneumatic and pulsed dye laser lithotripsy was not used. † Alligator graspers were not used. The ureteral stent designs may have been too similar to generate statistically significant differences in USSQ pain scores and, thus, each stent was equally comfortable. However, other data potentially support the hypothesis that less material in the bladder was associated with enhanced comfort. Patients who received an SLT stent had lower USSQ pain scores on day 4 after placement and lower pain medication use on day 1 after placement, when pain peaked in all stent groups. Compared to all other stent recipients, patients who received an LLT stent appeared to experience more pain, in that mean pain medication use was higher on days 1 and 2, and 3 (each p ⬍0.05). Furthermore, a greater proportion of patients who received an LLT stent reported flank pain and suprapubic pain compared to the other patients. Finally, all AEs of flank pain that led to hospitalization were experienced by patients who received a LLT stent. These observations seem contradic- URETERAL STENT DESIGN AND COMFORT Table 3. Breakdown of 103 procedure related AEs Condition No. PPC (%) No. PC (%) No. LLT Stent (%) No. SLT Stent (%) Overall Abdominal pain Nausea Vomiting Rigors Fever Catheter migration Fungal infection Urosepsis Urinary tract infection Bladder/suprapubic pain/spasm Back pain Flank pain/colic Groin/testicular pain Headache/dizziness Suicidal ideation Dysuria Incontinence not otherwise specified Urgency Frequency Urethral pain Urinary retention Vesicoureteral reflux Acute renal failure Ureteral perforation Hematuria Nocturia Respiratory problem 24 1 (4.2) 2 (8.3) 0 0 0 0 0 0 3 (12.5) 29 0 4 (13.8) 2 (6.9) 1 (3.4) 2 (6.9) 0 0 1 (3.4) 0 27 1 (3.7) 0 0 0 0 0 1 (3.7) 0 2 (7.4) 23 4 (17.3) 1 (4.3) 1 (4.3) 0 1 (4.3) 1 (4.3) 0 0 1 (4.3) 6 (25.0) 6 (20.6) 4 (14.8) 5 (21.7) 0 16 (66.7) 0 1 (3.4) 15 (51.7) 2 (6.9) 0 20 (74.1) 0 1 (4.3) 10 (43.5) 1 (4.3) 0 0 11 (45.8) 3 (12.5) 2 (6.9) 0 10 (34.5) 0 1 (3.7) 1 (3.7) 7 (25.9) 0 0 0 7 (30.4) 0 7 (29.2) 9 (37.5) 0 1 (4.2) 0 2 (6.9) 3 (10.3) 0 0 0 6 (22.2) 6 (22.2) 0 1 (3.7) 1 (3.7) 8 (34.8) 5 (21.7) 2 (8.7) 1 (4.3) 0 0 0 0 0 1 (3.7) 1 (3.7) 0 0 15 (62.5) 1 (4.2) 0 13 (44.8) 0 0 12 (44.4) 1 (3.7) 0 12 (52.2) 0 1 (4.3) tory to the study central hypothesis of less stent material in the bladder or intramural ureter resulting in less patient discomfort, especially since the SLT and LLT stents maintain an identical mass in the bladder. However, the additional loop length of the LLT stent resides in the ureter. Therefore, the etiology of pain caused by loop tailed ureteral stents may involve a combination of the stent distal end profile, length, mass and movement within the bladder or ureter, or at the ureteral orifice. The study design validating the USSQ was based on a comparison of USSQ scores in stented and nonstented cases.6 In contrast to this all or none study design, in the current study we assessed patient comfort among 4 stents with only subtle design differences. Therefore, USSQ by design may not have been sufficiently sensitive to detect differences in comfort among patients receiving similarly designed stents. Furthermore, post hoc statistical modeling in the current investigation indicated that a 2585 study population of approximately 1,000 patients was needed to show statistical separation among the 4 study and control ureteral stents. Therefore, only a quarter of the necessary number of patients were analyzed and no statistically or clinically significant differences in patient comfort could have been observed among the stents at any time point. Recently Lee et al reported no statistically significant differences in USSQ pain scores in 44 patients who completed the questionnaire 1, 3 and 5 days after ureteral stent placement.10 USSQ is a lengthy and complicated instrument. Patient psychological and physical status in the days immediately following ureteral stent placement can create a motivational challenge for completing USSQ. Some groups who have studied comfort have acknowledged the issue of patient discomfort in regard to USSQ complexity and they have used ad hoc questionnaires, while others have adapted existing instruments validated for other symptoms, eg following prostate biopsy,11,12 although the USSQ was available. Modifying USSQ by abridging it or validating its modules for discrete or improvisational use may enhance its usefulness in more diverse clinical study settings. Table 4. Breakdown of 94 device related AEs Condition No. PPC (%) No. PC (%) No. LLT Stent (%) No. SLT Stent (%) Overall Abdominal pain Nausea Vomiting Rigors Fever Catheter migration Urosepsis Urinary tract infection Bladder/suprapubic pain/spasm Back pain Flank pain/colic Groin/testicular pain Headache/dizziness Suicidal ideation Dysuria Incontinence not otherwise specified Urgency Frequency Urethral pain Urinary retention Vesicoureteral reflux Hematuria Nocturia 24 1 (4.2) 2 (8.3) 0 0 0 0 0 3 (12.5) 26 1 (3.8) 3 (11.5) 2 1 (3.8) 2 (7.7) 0 1 (3.8) 0 22 1 (4.5) 0 0 0 0 1 (4.5) 0 1 (4.5) 22 4 (18.1) 1 (4.5) 1 (4.5) 0 1 (4.5) 1 (4.5) 0 1 (4.5) 6 (25.0) 5 (19.2) 6 (27.2) 5 (22.7) 0 15 (62.5) 0 1 (3.8) 14 (53.8) 1 (3.8) 0 18 (81.8) 0 1 (4.5) 9 (40.9) 1 (4.5) 0 0 11 (45.8) 4 (16.7) 2 (6.9) 0 10 (38.5) 1 (3.8) 0 1 (4.5) 7 (25.9) 2 (9.1) 0 0 7 (31.8) 0 10 (41.7) 12 (50.0) 0 0 0 3 (11.5) 4 (15.4) 1 (3.8) 0 1 (3.8) 9 (40.9) 9 (40.9) 0 0 1 (4.5) 8 (36.4) 6 (27.3) 2 (9.1) 1 (4.5) 0 14 (58.3) 1 (4.2) 10 (38.5) 1 (3.8) 10 (45.5) 2 (9.1) 10 (45.5) 0 2586 URETERAL STENT DESIGN AND COMFORT Table 5. USSQ P3 to P9 combined body pain scores for each stent from days 4 to 30 Mean Score (range) No. pts Day 4 Day 30 Day 4–30 change PPC PC LLT Stent SLT Stent Totals 54 28.72 (0.0–64.1) 5.79 (0.0–34.9) ⫺22.93 (⫺64.1–14.0) 49 27.86 (0.0–76.0) 7.75 (0.0–41.0) ⫺20.11 (⫺76.0–25.4) 49 29.37 (0.0–63.5) 7.74 (0.0–39.4) ⫺21.63 (⫺55.0–17.9) 55 25.99 (0.0–73.5) 6.81 (0.0–49.3) ⫺19.19 (⫺73.5–21.2) 207 27.95 (0.0–76.0) 6.98 (0.0–49.3) ⫺20.96 (⫺76.0–25.4) The timing of USSQ administration may have a role in obtaining robust data. In its validation study USSQ administration time points reflected management regimens in the United Kingdom,6 where ureteral stents are typically placed for an extended duration between physician visits. The current study was performed primarily in the United States, where stents are typically placed for a shorter duration. In the current study pain was assessed by USSQ on baseline, on day 4 after placement and on day 30 after removal. However, data on pain medication use indicated that patients experienced peak pain 1 day after stent placement. Therefore, USSQ was administered when patient pain was subsiding. Had maximum potential pain scores been obtained, differences among the stents on day 30 may have shown greater separation. In a study comparing comfort among multiple similarly designed stents the optimal timing for USSQ administration appears to be 1 to 2 days after the stent is placed. Certain study limitations must be recognized. Each study arm included an unequal number of patients because the study was terminated early after interim statistical analysis demonstrated no significant differences among the study arms. Stent- p Value 0.344 0.715 ing duration was not fixed among the study arms to allow variations in clinical practices and treatment scenarios. Finally, 2 control stents were used, although PC and PPC have similar designs and materials. Using 2 different control groups we could expand the study by further comparing different standard double pigtail stents. Despite these limitations to our knowledge the current study is the first to compare the near term comfort of indwelling ureteral stents using USSQ in a large clinical study population involving a comparison of multiple stent types. In future investigations comparing stent comfort study design considerations must include appropriate statistical powering and clinical assessments. The required population size will create challenges from the perspectives of multiple investigational centers, patient enrollment, the effect on study duration and total cost. Survey instruments designed to measure patient subjective assessments of comfort and pain must be appropriately timed and administered to coincide with expected maximum and minimum periods of comfort. Objective study assessments should be measured, such as events of early stent removal, new or increased pain medication use or pill counts, or the need for unscheduled physician Table 6. Analgesia with acetaminophen plus 325 mg/5 mg oxycodone or 500 mg/5 mg hydrocodone PPC No. pts Day 0: No. pts Mean No. Day 1: No. pts Mean No. Day 2: No. pts Mean No. Day 3: No. pts Mean No. Day 4: No. pts Mean No. Overall: No. pts Mean No. PC LLT Stent SLT Stent Totals p Value 59 49 49 52 209 tablets (range) 46 2.07 (0.0–10.0) 36 1.78 (0.0–12.0) 40 2.61 (0.0–8.0) 40 1.98 (0.0–5.0) 162 2.11 (0.0–12.0) 0.379 tablets (range) 47 3.87 (0.0–15.0) 41 4.00 (0.0–12.0) 41 5.05 (0.0–10.0) 42 3.60 (0.0–12.0) 171 4.12 (0.0–15.0) 0.137 tablets (range) 47 3.70 (0.0–12.0) 40 3.40 (0.0–12.0) 41 4.93 (0.0–11.0) 42 3.15 (0.0–12.0) 170 3.79 (0.0–12.0) 0.045 tablets (range) 48 3.17 (0.0–10.0) 39 2.56 (0.0–12.0) 41 4.44 (0.0–16.0) 41 2.83 (0.0–12.0) 169 3.25 (0.0–16.0) 0.036 tablets (range) 47 2.28 (0.0–9.0) 36 2.06 (0.0–10.0) 40 2.18 (0.0–10.0) 41 1.68 (0.0–12.0) 164 2.05 (0.0–12.0) 0.688 tablets (range) 49 14.37 (1.0–54.0) 43 12.51 (0.0–58.0) 41 19.09 (4.0–46.0) 42 13.04 (0.0–47.0) 175 14.70 (0.0–58.0) 0.035 URETERAL STENT DESIGN AND COMFORT visits. Clearly there are many considerations for future clinical investigations of patient comfort after ureteral stent placement. APPENDIX USSQ Components USSQ Component Extent of body pain CONCLUSIONS We examined the hypothesis that substituting the distal pigtail end of a ureteral stent with an SLT or LLT design would enhance patient comfort in regard to less mass and material in situ. Patients who received an SLT stent had lower USSQ pain scores on day 4 after placement and lower pain medication use on day 1 after placement, when pain peaked in all stent groups. The absence of statistically significant differences among USSQ pain scores in patients with the different stents suggests that USSQ may be better suited for longer term comparisons among stented and nonstented cases, rather than in this short-term study design. Future studies of ureteral stent comfort will require balancing subjective and objective end points. Opportunities exist for further studies and survey instrument development. 2587 Location of body pain† Urinary tract symptoms Other USSQ information Parameters 7 Questions: P3, a VAS (0—no pain/discomfort to 10— worst possible pain)* P4 to P9, multiple choice questions VAS rating (P3) at 4 locations (females) and 5 locations (males): Kidney front/side area Groin area Bladder area Kidney back (flank) area Penis (males only) 11 Multiple choice questions (U1 to U11) General health, work performance, sexual matters and additional problems * The VAS was read by 2 readers. When the 2 readings were not within 0.5 points, the readings were adjudicated by a third reader. † The pictorial question P3 (extent of body pain) asked the patient to rate pain on the VAS at 4 locations (females) and 5 locations (males). Therefore, the maximum score in females was 40 and in males it was 50. The scale in women was normalized to 50 to have the same scale in all patients, including the 2 sexes. 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