Objective
The objective of the study was to evaluate objective and subjective outcomes of MiniArc and Monarc (American Medical Systems, Minnetonka, MN) midurethral sling (MUS) in women with stress incontinence at 12 months.
Study Design
A total of 225 women were randomized to receive MiniArc or Monarc. Women with intrinsic sphincter deficiency, previous MUS, or untreated detrusor overactivity were excluded. Objective cure was defined as negative cough stress test with a comfortably full bladder. Subjective cure was defined as no report of leakage with coughing or exercise on questionnaire. Validated questionnaires, together with urodynamic and clinical cough stress test, were used to evaluate the objective and subjective outcomes following surgery. Participants and clinicians were not masked to treatment allocation. Outcomes were compared with exact binomial tests (eg, Fisher exact test for dichotomous data) for categorical data and Student t tests or exact versions of Wilcoxon tests for numerical data as appropriate.
Results
There was no statistically significant difference in the subjective (92.2% vs 94.2%; P = .78; difference, 2.0%; 95% confidence interval, –2.7% to +6.7%) or objective (94.4% vs 96.7%; P = .50; difference, 2.3%; 95% confidence interval, –1.5% to +6.1%) cure rates between MiniArc and Monarc at 12 m, respectively, with a significant improvement in overactive bladder outcomes and incontinence impact from baseline in both arms.
Conclusion
MiniArc outcomes are not inferior to Monarc MUS outcomes at 12 months’ follow-up in women without intrinsic sphincter deficiency.
Female stress urinary incontinence (SUI) is a prevalent, costly, and burdensome condition for women. Surgery for female SUI has increased, with midurethral slings procedures (MUS) becoming increasingly popular. Systematic reviews have shown MUS to be just as effective as traditional continence operations such as pubovaginal slings or Burch colposuspension.
Although the first modern MUS was described more than 15 years ago using a retropubic approach, the transobturator approach was introduced 5 years later in an attempt to reduce potential complications by avoiding the Cave of Retzius. When compared with the transobturator approach, an increased rate of bladder perforations and pelvic hematomas were observed among those who had retropubic MUS, despite a largely equivalent cure rate in the medium term. However, both retropubic and transobturator MUS continue to have clinically significant complications such as bladder injuries, mesh exposures, voiding difficulties, de novo urgency, and groin/thigh pain.
Single-incision slings, such as the MiniArc (American Medical Systems, Minnetonka, MN), are designed with self-anchoring mechanisms to the pelvic sidewalls and require no trocar passage through the obturator foramen or external skin incisions, which could reduce postoperative pain and shorten postoperative recovery. Early case series of 12-month follow-up showed limited length of stay, a low complication rate, and minimal postoperative pain with a high cure rate, suggestive of a potential clinical advantage.
A retrospective cohort comparative study of MiniArc and Monarc (American Medical Systems) showed a comparable objective cure, incontinence impact, and satisfaction at 12-month follow-up. Our aim was to examine the cure rates and perioperative outcomes of Monarc and MiniArc at 6 and 12 months in a randomized controlled trial (RCT).
Materials and Methods
In this pragmatic RCT, women who had SUI or urodynamic stress incontinence who failed conservative treatments and requested surgery were recruited between May 30, 2009, and Dec. 14, 2011, from tertiary urogynecology clinics. All recruited women reported SUI.
Women with intrinsic sphincter deficiency (ISD), previous MUS, untreated detrusor overactivity, or significant voiding dysfunction (maximum flow rate <15 mL/s or <10% Liverpool nomogram and/or postvoid residual >100 mL) were excluded. ISD was defined as either a maximum urethral closure pressure (MUCP) of 20 cm H 2 O or less with the bladder empty or at capacity and/or a pressure rise from baseline required to cause urinary incontinence (Δ valsalva or cough leak point pressure) of 60 cm H 2 O or less. Women with concomitant prolapse or mixed urinary incontinence were not excluded.
Women were randomized, in a 1:1 ratio, to receive either MiniArc or Monarc. Computer-generated random allocation was concealed and stratified by center. Surgeons or patients were not blinded once allocation was revealed. Surgeries were performed, according to the manufacturer’s instructions, by surgeons who were already proficient with Monarc MUS and had already performed at least 10 MiniArc procedures, which was tensioned to snug fitting. All women underwent general anesthetic for their surgeries. Cystourethroscopy was routinely performed for all cases. Postoperative analgesia (for patients undergoing MUS only) and voiding assessment were standardized for both groups.
At baseline comprehensive patient data including demographics, medical history, symptoms of lower urinary tract, and pelvic floor dysfunction were documented, followed by physical examination and urodynamic and surgical reports. Standardized proformas at each time point, together with validated patient reported outcome (PRO) tools, including the International Consultation on Icontinence Questionnaire (ICIQ), Urinary Incontinence Short Form (UI SF), ICIQ Overactive Bladder (OAB), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire 12, Incontinence Impact (IIQ)7, Patient Global Impression of Improvement (PGII) and 24 hour pad weight, were used to facilitate prospective collection of data to evaluate objective and subjective outcomes following surgery. These PRO tools measure symptom severity, storage symptoms, incontinence impact, sexual function, and global rating, respectively.
Operative data were collected on the subset of women who underwent sling only, without concomitant prolapse surgery; they include operative time, estimated blood loss, and analgesia usage in the first 24 hours. Patients were seen at 6 weeks, 6 months, and 12 months for a clinical examination. Urodynamic studies were performed preoperatively and at 6 months postoperatively except when the patient declined, in which case a clinical cough stress test (also at 12 months), with a comfortably full bladder, was performed. The clinical cough stress test was generally done in the supine position with a minimum of 3 coughs.
Objective cure was defined as a negative urodynamic stress or cough stress test at 6 months and a negative cough stress test at 12 months. Subjective cure was defined as an absence of recorded leakage with coughing and exercise on questions 3 and 5 of the International Consultation on Incontinence Questionnaire–Urinary Incontinence Short Form.
Primary outcome at 12 months was objective cure. Secondary outcomes were subjective cure, reoperation rates, and changes in ICIQ UI SF, ICIQ OAB, IIQ7, PISQ-12, and PGII. Definitions, outcome measures, and standardized reporting adhered to International UroGynecological Association/International Continence Society terminology, International UroGynecological Association, and Consolidated Standards of Reporting Trials (CONSORT) guidelines.
Institution ethics approval (R08-43, 08188B) was obtained and the trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12608000624381). Written consent was obtained from patients for participation in the study. Assuming an objective cure rate of 85% for Monarc, this RCT was powered (80%) to detect a clinical difference of 15% and allows for an attrition of 15% with a sample size of 220, using a 1-sided α of 0.05.
Outcomes were compared with exact binomial tests (eg, Fisher exact test for dichotomous data) for categorical data and Student t tests or exact versions of Wilcoxon tests for numerical data as appropriate. Multivariate logistic regression analyses on 12m objective and subjective outcomes of preoperative data, including different surgeons, were conducted to control for potential confounding bias. All analyses were conducted using the statistical package SPSS version 22 (SPSS Inc, Chicago, IL).
Results
The mean age of all patients was 51.6 ± 9.71 years (range, 31–80 years), body mass index (BMI) of 27.5 ± 5.6 kg/m 2 (range, 15.2–46.9 kg/m 2 ), and a median parity of 2 (quartiles 2–3; range, 0–7). Figure 1 depicted the CONSORT flowchart, accounting for all participants, including those lost to follow-up and those who were eligible but declined to participate.
Table 1 displayed baseline characteristics of women who received allocation to either sling. It showed no statistically significant difference between the 2 treatment arms for known confounders, which included age, parity, BMI, prior medical history, baseline symptom severity (excluding Patient Global Impression of Severity), urodynamic diagnosis, vaginal topography, and types of concomitant prolapse surgeries.
| Demographic | MiniArc (n = 112) | Monarc (n = 113) | P value |
|---|---|---|---|
| Age, y, mean ± SD | 52.2 ± 10.0 | 51.0 ± 9.4 | .33 |
| Parity a | 2 (2–3) | 2 (2–3) | .68 |
| BMI, mean ± SD | 27.4 ± 5.8 | 27.6 ± 5.5 | .71 |
| Menopause, % | 50 (44.6) | 49 (43.4) | .89 |
| Previous hysterectomy, % | 25 (22.4) | 22 (19.4) | .79 |
| Previous POP surgery, % | 8 (7.1) | 6 (5.3) | .60 |
| Previous SUI surgery, % | 4 (3.6) | 2 (1.8) | .68 |
| Chest neuro DM CT, % | 18 (16.2) | 19 (16.8) | > .99 |
| Baseline functional outcomes | |||
| ICIQ UI SF a | 13 (10–16) | 14 (10–16) | .37 |
| Antimuscarinic use, % | 17 (14.4) | 16 (14.2) | > .99 |
| ICIQ OAB a | 5 (3–8) | 5 (3–8) | .72 |
| PISQ12 a | 33 (28–37) | 33 (29–38) | .91 |
| Not sexually active, % | 21 (18.8) | 23 (20.7) | .74 |
| IIQ7 a | 9 (5–13) | 9 (5–12) | .65 |
| PGI-S a | 3 (2–3) | 3 (3–3) | .04 b |
| 24 hour pad, g, mean ± SD c | 21.1 ± 33.9 | 28.5 ± 43.1 | .22 |
| Urodynamic findings | |||
| USI, % | 99 (90.0) | 100 (90.9) | > .99 |
| DO, % | 11 (10.0) | 5 (4.5) | .19 |
| MUCP, mean ± SD | 40.3 ± 15.5 | 40.9 ± 17 | .79 |
| ALPP, mean ± SD | 107 ± 29.0 | 109.8 ± 51.5 | .65 |
| POPq | |||
| Ba, mean ± SD | −1.47 ± 1.10 | −1.29 ± 1.20 | .24 |
| Bp, mean ± SD | −1.28 ± 1.19 | −1.18 ± 1.45 | .57 |
| C, mean ± SD | −6.05 ± 1.82 | −5.92 ± 2.56 | .62 |
| Prolapse surgery | |||
| Concomitant POP, % | 44 (39.3) | 54 (47.8) | .23 |
| VH ± A/P or AP, % | 23 (20.5) | 35 (31.0) | .09 |
| Anterior mesh or ASC, % | 5 (4.5) | 4 (3.5) | .75 |
| Posterior only ± mesh, % | 16 (14.3) | 15 (13.3) | .85 |
a Median (interquartile range, 25–75%)
c Proportion of completed pad tests were 66.1% for Miniarc and 98.2% for Monarc (American Medical Systems, Minnetonka, MN).
Table 2 detailed intraoperative and postoperative data to 6 weeks. For women who underwent sling only (without concomitant prolapse surgery), the Monarc procedure was longer by half a minute (8.5 vs 8.0 minutes, P = .002) with women requiring more analgesia (2 vs 0.5 tablets, P = .002) in the first 24 hours and more women reporting short-term groin pain (34 vs 10, P < .001), although the observed larger (medians of 4 vs 1) number of women requiring catheter longer than 24 hours did not reach statistical significance. For those who underwent the concomitant prolapse procedure, more women who had Monarc required a catheter for 1–2 days (19 vs 2, P = .0003) compared with those who had MiniArc.
| Sling only | MiniArc (n = 68) | Monarc (n = 59) | P value |
|---|---|---|---|
| Time, min a | 8.0 (6.0–10.0) | 8.5 (8.0–12.0) | .002 b |
| Catheter longer than 1 d | 1 | 4 | .170 |
| Panadeine use a | 0.5 (0.0–2.0) | 2.0 (0.3–6.0) | .002 b |
| Groin pain | 10 | 34 | < .001 b |
| Duration 1–3 d | 2 | 20 | |
| Duration 4–7 d | 5 | 7 | |
| Duration 2–4 wks | 3 | 7 | |
| Concomitant POP | MiniArc (n = 44) | Monarc (n = 54) | |
| Catheter 1–2 d | 2 | 19 | .0003 b |
| Catheter 3–4 d | 1 | 1 | |
| Catheter 7 d | 1 | 1 |
a Median (interquartile range, 25–75%) panadeine use reflects usage in 24 hours
Table 3 detailed subjective and objective cure rates at 6 and 12 months. Subjective cure rates were very similar between the MiniArc and Monarc patients at 6 months (95.5% vs 92.5%, P = .4) and at 12 months (92.2% vs 94.2%, P = .78), respectively. This mirrored the similar objective cure rates between MiniArc and Monarc at 6 months (81.1% vs 86.3%, P = .43) and at 12 months (94.4% vs 96.7%, P = .50), respectively.
| Cure rates | MiniArc (n = 112) | Monarc (n = 113) | P value | |||
|---|---|---|---|---|---|---|
| 6 mo | 12 mo | 6 mo | 12 mo | 6 m vs 6 mo | 12 m vs 12 mo | |
| Subjective | 105/110 | 95/103 | 99/107 | 97/103 | .40 | .78 |
| % | 95.5 | 92.2 | 92.5 | 94.2 | ||
| Objective | 77/95 | 84/89 | 82/95 | 87/90 | .43 | .50 |
| % | 81.1 | 94.4 | 86.3 | 96.7 | ||
| Sling only | Sling only | |||||
| Subjective | 63/66 | 57/62 | 52/56 | 49/57 | .70 | > .99 |
| % | 95.5 | 91.9 | 92.9 | 90.7 | ||
| Objective | 47/58 | 47/51 | 43/51 | 42/45 | .80 | > .99 |
| % | 81.0 | 92.2 | 84.3 | 93.3 | ||
Objective cure was determined on the basis of an absence of urodynamic stress incontinence at 6 months, whereas it was determined by a negative clinical cough stress test at 12 months, which explains the change in objective cure rate. Similar subjective and objective cure was seen for those who had either MiniArc or Monarc only (ie, no concomitant prolapse surgery) at 6 and 12 months.
Assuming all missing data were failures, similar subjective and objective cure rates were observed between the 2 treatment arms at 6 or 12 months, including those who had sling only. Specifically, at 6 months, the subjective/objective cure rates for MiniArc and Monarc were 93.8% and 87.6% and 68.8% and 72.5%, respectively. At 12 months, assuming all lost to follow-up were failures, the subjective/objective cure rates for MiniArc and Monarc were 84.8% and 85.8% and 75% and 77%, respectively.
In Table 4 , functional outcomes (patient reported symptom distress, incontinence impact, and sexual outcomes) between the 2 treatment arms at 6 and 12 months are tabulated, and Figure 2 depicted the box-whisker plots (median/interquartile scores) of PROs (ICIQ UI SF, ICIQ OAB, IIQ7, Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire 12, and PGII) from both slings at baseline, 6 months, and 12 months. There was no statistically significant difference in the ICIQ UI or ICIQ OAB score between both arms at 6 or 12 months, although the proportion using antimuscarinics was lower for women who had the MiniArc sling at 12 months compared with those who had Monarc (5.7% vs 15.8%, P = .034).
| Outcome | MiniArc (n = 112) | Monarc (n = 113) | P value | |||
|---|---|---|---|---|---|---|
| 6 mo | 12 mo | 6 mo | 12 mo | 6 mo vs 6 mo | 12 mo vs 12 mo | |
| ICIQ UI SF a | 4 (0–7) | 4 (0–6) | 3 (0–6) | 3 (0–6) | .77 | .61 |
| b | 9 | 14 | 10 | 18 | ||
| ICIQ OAB a | 3 (2–5) | 3 (1–4) | 3 (2–5) | 3 (2–5) | .57 | .48 |
| b | 8 | 10 | 11 | 17 | ||
| OAB Medications | 10/92 10.9% | 5/87 5.7% | 14/96 14.6% | 15/95 15.8% | .52 | .034 c |
| b | 20 | 25 | 17 | 18 | ||
| PISQ12 a | 36 (33–40) | 37 (34–41) | 39 (33–41) | 38 (33–41) | .06 | .91 |
| b | 34 | 43 | 39 | 40 | ||
| NSA | 25/103 | 26/95 | 29/103 | 22/95 | .64 | .62 |
| b | 9 | 17 | 10 | 18 | ||
| IIQ7 a | 0 (0–4) | 0 (0–3) | 0 (0–3) | 0 (0–3) | .70 | .88 |
| b | 10 | 14 | 10 | 20 | ||
| PGII a | 1 (1–2) | 1 (1–2) | 1 (1–2) | 1 (1–2) | .90 | .46 |
| b | 10 | 14 | 11 | 19 | ||
| 24 hour pad a | 4 (0–8) | 2 (2–6) | .89 | |||
| b | 46 | 54 | ||||
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