A Randomized Controlled Trial Comparing Retropubic KIM Sling to TVT Exact Midurethral Sling
Phase: NA
Conditions: Stress Urinary Incontinence
Sponsor: University of North Carolina, Chapel Hill

 
 
 
 
 
 
 
A Randomized Controlled Trial Comparing Retropubic KIM sling to TVT Exact Midurethral Sling 
 
 
 
NCT number:  NCT04985799 
 
 
Document Date: April 15, 2021 
 
 
 
 

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A Randomized Controlled Trial Comparing Retropubic KIM sling to TVT Exact Midurethral Sling 
 
BACKGROUND / RATIONALE 
Midurethral slings (MUS) are recognized as a minimally invasive treatment of stress urinary 
incontinence (SUI). The retropubic route of MUS placement has a cure rate of 89.1%1 with long term 
subjective cure rates ranging from 51-88%.2 The Neomedic Knotless Incontinence Mesh (KIM) sling is a 
tension-free macroporous monofilament polypropylene knotless mesh designed to be resistant to 
elongation and deformation over time.3 The KIM sling also offers a reusable trocar, which results in less 
waste and cost- savings. KIM sling trocars are available for the retropubic route or trans-obturator (TOT) 
route. 
While studies have been performed comparing the TOT approach of the KIM sling to other slings, no 
studies have been performed to date with the retropubic (RP) approach. The RP and TOT approaches to 
MUS have been shown to be equivalent in the treatment of SUI.4 Since the same mesh material of the 
KIM sling is used for both the TOT and RP approach, we can conclude that the RP route would show 
similar treatment success rates.   
A type 1 macroporous (> 75um) polypropylene mesh is the most appropriate material for vaginal 
implantation.5 Currently in our practice we use the Gynecare TVT Exact sling, which meets these 
requirements. However, Chapple et al suggest that the design and weave of synthetic mesh material can 
also have a significant effect on efficacy and safety;5 therefore, the novel design of the KIM may be 
beneficial to reduce complications. If we can show there is similar efficacy with the RP approach of the 
KIM sling to the TVT Exact, there will be benefit of reduced costs and the potential for less 
complications. With this study, our aim is to show non-inferiority of the KIM sling to the Gynecare TVT 
Exact.  
Given that the midurethral sling has been proven to be effective at treating stress urinary 
incontinence, and that lightweight, large pore mesh has less adverse effects, we propose a randomized 
trial to show noninferiority of the Neomedic KIM sling compared to the well-studied Gynecare TVT Exact 
sling.  The study population will be patients that have clinically demonstrated SUI and have already 
chosen to pursue midurethral sling surgery for treatment. Validated questionnaires will be used to 
evaluate the subjective response to treatment, as a subjective outcome most closely relates to patient 
experience and satisfaction.  
 
STUDY AIMS 
Primary aim: Our primary aim is to assess to the non-inferiority of the retropubic Neomedic KIM sling 
compared to the Gynecare TVT Exact sling at 6 weeks. 
 
We hypothesize that the KIM sling will be non-inferior to the TVT exact sling at 6 weeks postoperatively. 
 
Secondary aims:  
• 
To assess the non-inferiority in effectiveness of the retropubic Neomedic KIM sling compared to 
Gynecare TVT Exact at 1 year post-operatively.  
 
• 
To assess safety of the Neomedic KIM sling compared to the Gynecare TVT Exact sling with 
regards to mesh exposure and reoperation for urinary retention or mesh complications at 1 year 
postoperatively. 
 
 

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STUDY DESIGN & METHODS 
This is a randomized controlled, double-blinded, non-inferiority trial comparing effectiveness and safety 
of the Neomedic KIM midurethral sling to Gynecare TVT exact midurethral sling  
 
Study Population 
Inclusion criteria: 
• 
Women ≥21 years based on medical chart review 
• 
Diagnosis of SUI or mixed urinary incontinence based on medical chart review 
• 
Objective evidence of SUI as indicated by positive cough stress test or urodynamic stress 
incontinence during urodynamic testing within the last year prior to enrollment. Medical 
chart will be reviewed. 
• 
Planning surgery for SUI with/without POP surgery  
 
Exclusion criteria: 
• 
Current Pregnancy, desire for future childbearing, or ≤12 months postpartum at the time of 
enrollment  
• 
Prior history of surgery for SUI based on medical chart review 
• 
Bladder capacity <200mL on Urodynamic testing or PVR >150mL on Urodynamic testing or 
bladder scan.  
• 
Non-ambulatory 
• 
Current genitourinary fistula or urethral diverticulum based on pre-operative exam in the 
medical chart. 
 
Outcome measures 
 
Primary outcome: SUI treatment success at 6 weeks post-operatively. Treatment success will be based 
on a composite outcome of: 
- 
Response of “No” on UDI-6 (subscale of PFDI-20), question #3 OR if answered “yes”, must 
indicate “no bother” 
- 
No re-treatment with a pessary, other incontinence device or repeat surgery (urethral bulking, 
Burch urethropexy, sling, or other procedure) 
 
Secondary outcomes: 
1. SUI treatment success at 1 year 
a. Uses same composite outcome criteria as primary outcome 
2. Complication rates at 1 year 
a. Urinary retention 
b. Mesh exposure- determined by physical exam at 1 year 
c. Reoperation for urinary retention or mesh complications thru 1 year 
 
Baseline characteristics will be used to define the study population. Variables to be collected:  
• 
Age- number 
• 
Race- Caucasian/ Black/ American Indian or Alaskan Native/ Asian/ Pacific Islander/ Other 
• 
Ethnicity- Hispanic/ non-Hispanic 
• 
BMI- number 
• 
POP-Q points- number 

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• 
Smoking status- non-smoker/ current/ former 
• 
Past medical history 
o Diabetes- yes/no 
o Charlson comorbidity index- number 
• 
Past surgical history 
o Prior hysterectomy- yes/no 
o Prior prolapse surgery- yes/no 
o Prior surgery for SUI- yes/no 
o Prior bladder tack surgery- yes/no 
 
Data of concurrent surgical treatment at the time of intervention, which will be used to define the study 
population: 
• 
Hysterectomy 
• 
Anterior repair 
• 
Posterior repair 
• 
Apical suspension 
o Uterosacral ligament suspension 
o Sacrospinous ligament fixation 
o Sacrocolpopexy 
 
 
Study Intervention 
The KIM sling is a tension-free Knotless Incontinence Mesh (KIM) sling. Any patient with female 
stress urinary incontinence can be a candidate for this sling. The KIM system provides support under the 
urethra to decrease stress urinary incontinence in patients, similar to other slings. As opposed to other 
slings on the market, KIM-specific benefits include being knotless which could decrease the friction 
between the permanent product and patient tissue which could decrease the risk of erosion or bacteria. 
The sling is placed via a short, outpatient procedure where a small vaginal incision is made with two exit 
points through the skin. Patients can be discharged on the same day of surgery. Of note, the KIM sling 
also allows for a reusable trocar system.8  
 
Study participants will be randomized to receive the Gynecare TVT Exact sling or the Neomedic KIM 
sling in the operating room by a trained Urogynecologist.  
Participating surgeons will undergo training on how to place KIM sling. This includes but is not 
limited to teaching or device representatives in the operating room for intraoperative questions. These 
surgeons already have experience in placing Gynecare TVT Exact slings, as this is the current standard of 
care.  The KIM sling has subtle differences in placement which will be addressed at the training. All 
surgeons in the study will undergo one training together prior to the start of the study and will have 
individual help from device representatives.   
 
Randomization, Concealment, and Blinding 
The randomization schema will be created using Stata, and this schema will be uploaded into the 
REDCap database, where randomization will be performed and maintained. This technique will be used 
to prevent selection bias by concealing the allocations from those assigning participants until the 
moment of assignment. Randomization will occur in the operating room prior to performing the 
procedure. Assignment codes will remain within REDCap with access to the randomization for the 
research investigators. The randomization codes will not be broken unless knowing the sling type affects 

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the patient’s health or if there is a complication postoperatively that requires knowing the type of sling 
placed.  
 
Masking (Blinding)  
This study will be double blinded. While the providers in the operating room placing the sling will not be 
able to be blinded, the subjects and data collectors will be blinded to the treatment assignment.   
 
Study Procedures and Schedule 
 
Procedures 
 Screening  
 Baseline  
  
  Intervention 
 6 weeks visit 
 6 month visit 
 1 year visit 
  
Eligibility Assessment 
X 
 
 
 
 
 
Informed Consent 
 
X 
 
 
 
 
Medical History 
 
X 
 
 
 
 
Study Intervention 
 
 
X 
 
 
 
PFDI-20 
 
X 
 
X 
X 
X 
PGI-I 
 
 
 
X 
X 
X 
Symptom Questionnaire 
 
 
 
X 
X 
X 
Physical Exam 
 
 
 
X 
 
X 
 
Screening (within 6 months prior to enrollment) 
Pre-screening will be performed through a provider visit, obtaining history, physical exam and 
urodynamics study if needed, where the patient will be evaluated for if they are eligible for a sling.  If 
the patient is deemed eligible, they will verbally be consented to be screened for and contacted 
regarding the research study.  The research coordinator will screen for eligibility and will contact the 
patient to further discuss the study. This screening will take place within 6 months prior to enrollment.   
 
Enrollment / Baseline (Day 0) 
• 
Informed consent 
• 
PDFI-20 
• 
Obtain baseline characteristics (medical history) 
Visit 1 (Surgical intervention- within 6 months of enrollment) 
• 
Intervention- randomized to treatment 
Visit 2 (6 ± 2 weeks from intervention) 
• 
PFDI-20 
• 
PGI-I 
• 
Symptom questionnaire 
• 
Physical exam 
• 
Adverse event / SAE assessment 
Visit 3- phone (6 ± 2 months) 
 
• 
PFDI-20 
• 
PGI-I 
• 
Symptom questionnaire 

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• 
Adverse event / SAE assessment 
Final Visit (1 year ± 2 months) 
 
• 
PFDI-20 
• 
PGI-I 
• 
Symptom questionnaire 
• 
Physical exam 
• 
Adverse event / SAE assessment 
 
Statistical Analysis Plan 
 
Strategies that Apply to all the Specific Aims 
• 
To help ensure replicability of the research, the analysis plans will be reviewed and finalized 
prior to collection of data (a priori). For each specific aim, the analysis plans specify detailed 
steps for obtaining estimates of population parameters (e.g., treatment effects) and for making 
inferences.   
• 
Descriptive graphical and tabular methods will be used to characterize the participants, visualize 
the data and examine relationships among variables. 
• 
For each specific aim, the analyses will focus on the magnitude and direction of point- and 
interval-estimates of the population parameters of interest. To indicate precision, all statistical 
estimates of population parameters will be tabulated along with corresponding confidence 
intervals (CI) or standard errors (SE). The CI will be interpreted as the set of potential values of 
the population parameter that are most compatible with the observed data.  
• 
All hypothesis tests yielding p-values that are deemed to be not statistically significant will be 
reported as being inconclusive. The proposed statistical analysis strategy acknowledges that no 
p-value can reveal the plausibility, presence, truth, or importance of an association or effect.    
 
 
Plans for Aim 1:  
To assess the non-inferiority in the effectiveness of the retropubic Neomedic KIM sling compared to 
Gynecare TVT Exact sling at 6 weeks, we will present the 2-by-2 contingency tables on SUI treatment 
success counts. Then, we will perform the one-sided hypothesis test of 𝐻𝐻0: (PTVT −PKIM) > ∆ vs 
𝐻𝐻𝑎𝑎: (PTVT −PKIM) ≤∆, where  PTVT is the proportion of success counts in the TVT sling group, 
PKIM is the proportion of success counts in the Neomedic KIM sling group, and ∆ is the conjectured 
inferiority margin. We will use the chi-squared test to test the above hypothesis. In addition, we will 
provide the 95% confidence interval of PTVT −PKIM. 
 
 
Plans for Aims 2:  
We will perform a similar analysis for Aim 1 to compare effectiveness at 1 year. 
 
To evaluate the complication rates of the retropubic KIM sling compared to the TVT Exact at 6 weeks 
and 1 year post-operatively, we will also present 2-by-2 contingency tables on complication counts 
(for urinary retention, mesh exposure and reoperation for mesh complications and urinary 
retention). We will perform a two-sided test on comparing the proportions of complications 
between KIM sling and TVT Exact sling groups. Again, such a test will be performed by using the chi-
squared test. In addition, we will provide the 95% confidence interval of the differences of the 
proportions between these two groups.  
 

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Sample Size Rationale 
Our statistical power calculation was based on prior studies showing retropubic sling success rate being 
89-95%1-5 and using 12-15% non-inferiority margin6-9. We based our sample size estimate on the 
following: 90% sling success with a 14% non-inferiority margin and 80% power, assuming a 20% dropout 
rate. If there is truly no difference between the standard and experimental treatment (90% in both 
groups), then 114 patients are required to be 80% sure that the upper limit of a one-sided 95% 
confidence interval (or equivalently a 90% two-sided confidence interval) will exclude a difference in 
favor of the standard group of more than 14%. To assume a 20% dropout rate, we needed to enroll 144 
participants for our primary outcome of treatment success at 6 weeks postoperatively. Sample size 
calculator used was https://www.sealedenvelope.com/power/binary-noninferior/. 
 
Recruitment Strategy  
Once a patient has been seen by a Urogynecology physician and plans to have sling surgery for SUI, the 
physician will notify the study team to screen for eligibility. After the study team determines eligibility, 
the patient will then be approached by the study team for recruitment.  
 
Retention Strategy  
The 6 week, 6 month and 1 year visits will be incentivized monetarily in order to enhance retention. 
Subjects will receive $25 with completion of the 6 week visit and $75 with completion of the 1 year visit. 
The 6 month visit will be performed over the phone and/or with REDCap surveys in order to reduce the 
burden on the participant.  
 
Screen Failures  
Those who are screened for the study but are not eligible will still undergo planned surgery for SUI but 
will not be enrolled or randomized to treatment. The patient will receive the treatment that is planned 
for with a shared medical decision-making process with their physician. 
 
 
REFERENCES 
1. 
Imamura M, Hudson J, Wallace SA, et al. Surgical interventions for women with stress urinary incontinence: 
systematic review and network meta-analysis of randomised controlled trials. BMJ 2019;365:l1842. (In eng). 
DOI: 10.1136/bmj.l1842. 
2. 
Liu HH, Kuo HC. Durability of Retropubic Suburethral Sling Procedure and Predictors for Successful Treatment 
Outcome in Women With Stress Urinary Incontinence. Urology 2019;131:83-88. (In eng). DOI: 
10.1016/j.urology.2019.05.015. 
3. 
Marschke J, Reisenauer C, Mikkola TS, Schwab F, Tunn R, Huebner M. Comparison of two retropubic tension-
free vaginal tape procedures in women with stress urinary incontinence: a randomized controlled 
multicenter trial. Arch Gynecol Obstet 2019;299(4):1015-1022. (In eng). DOI: 10.1007/s00404-019-05077-0. 
4. 
Aniuliene R, Aniulis P, Skaudickas D. TVT-Exact and midurethral sling (SLING-IUFT) operative procedures: a 
randomized study. Open Med (Wars) 2015;10(1):311-317. (In eng). DOI: 10.1515/med-2015-0046. 
5. 
Sun Y, Luo D, Yang L, et al. The Efficiency and Safety of Tension-Free Vaginal Tape (TVT) Abbrevo Procedure 
Versus TVT Exact in the Normal Weight and Overweight Patients Affected by Stress Urinary Incontinence. 
Urology 2017;110:63-69. (In eng). DOI: 10.1016/j.urology.2017.06.033. 
6. 
Richter HE, Albo ME, Zyczynski HM, et al. Retropubic versus transobturator midurethral slings for stress 
incontinence. N Engl J Med 2010;362(22):2066-76. (In eng). DOI: 10.1056/NEJMoa0912658. 
7. 
Albo ME, Richter HE, Brubaker L, et al. Burch colposuspension versus fascial sling to reduce urinary stress 
incontinence. N Engl J Med 2007;356(21):2143-55. (In eng). DOI: 10.1056/NEJMoa070416. 

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8. 
Barber MD, Kleeman S, Karram MM, et al. Transobturator Tape Compared With Tension-Free Vaginal Tape 
for the Treatment of Stress Urinary Incontinence: A Randomized Controlled Trial. Obstetrics & Gynecology 
2008;111(3):611-621. DOI: 10.1097/AOG.0b013e318162f22e. 
9. 
Karmakar D, Dwyer PL, Murray C, Schierlitz L, Dykes N, Zilberlicht A. Long-term effectiveness and safety of 
open Burch colposuspension vs retropubic midurethral sling for stress urinary incontinence—results from a 
large comparative study. American Journal of Obstetrics and Gynecology 2021;224(6):593.e1-593.e8. DOI: 
https://doi.org/10.1016/j.ajog.2020.11.043.