Open Journal of Urology, 2011, 1, 19-24
doi:10.4236/oju.2011.12006 Published Online May 2011 (
Copyright © 2011 SciRes. OJU
Cadaveric Assessment of Synthetic Mid-Urethral
Sling Placement
Scott Serels
Bladder Control Center of Norwalk, Norwalk CT, USA
Received March 5, 2011; revised April 25, 2011; accepted Ma y 5, 2011
Purpose: To determine if 3 types of mid-urethral synthetic slings are visually the same. Materials and Methods: A
retropubic, obturator, and single incision sling was individually placed in three cadavers. Tension was set using a spacer
(obturator and retropubic). Single incision sling (SIS) tension was set by visual inspection. Thirty physicians were asked
to determine placement method, tension, and location of the 3 slings. Results: Physicians were composed of 5 urolo-
gists, 7 urogynecologist, and 18 general gynecologists, with an average of 53 slings performed per year. Conclusions:
This study showed that after placement of a sling it is hard to tell how the sling was placed and that most physicians felt
the SIS was tensioned the best and most likely at the mid-urethra.
Retropubic Obturator SIS
% correctly identified sling 40% 43% 23%
% thought tension was just right 33% 47% 73%
% thought sling was at mid-urethra 50% 67% 83%
Keywords: Stress Incontin ence, Surgical Correction of Incontinence, Single Incision Slings
1. Introduction
Urinary incontinence is a common problem in adult
women, with a prevalence of approximately 35% [1].
Stress urinary incontinence (SUI), the most common form
of urinary incontinence in women, is an involuntary loss
of urine that occurs during physical activity, such as
coughing, sneezing, laughing, or exercise. Treatment
options for SUI in women are designed to prevent the
involuntary loss of urine from the urethra during increases
in intra-abdominal pressure. Nonsurgical therapies include
behavioral therapy (e.g. bladder training, fluid and dietary
modification) and l imit ed drug t herapy.
Surgical therapy for this condition has existed for over
100 years. The suburethral sling was first described in
1907 by von Giordano, and consisted of pl acing autol ogous
tissue underneath the bladder neck and suspending it
superiorly. Since then, over 200 different surgical
procedures have been described. Sling material has also
evolved from autologous fascia lata, muscle, and rectus
fascia to synthetic material. The majority of midurethral
slings now available u se type I polypropylene mesh. The
development of the mid-urethral slings and corresponding
placement methodologies have evolved to improve
efficacy, safety, cost-effectiveness, and to minimize
invasiveness. Currently, the three main approaches to
placement of synthetic mid urethral sling include
retropubic, transobturator, and the single incision mini
The Integral Theory of Female Urinary Incontinence
by Ulmsten and Petros in the early 1990’s challenged our
understanding of incontinence significantly and led to the
market introduction of the minimally invasive retropubic
midurethral sling known as tension-free vaginal tape
(TVT) [2]. The TVT procedure initiated in 1996
revolutionized the surgical manag ement of female SUI in
terms of its efficacy and minimal invasiveness. Although
80% - 89% cure rates, with durable cure rates up to 5
years post-procedure, have been reported, blind passage
through the retropubic space poses considerable risks.
[3,4] Pot enti al compli cati ons i ncl ude bowel i njury , bl adder
injury, major vascular injury, and nerve injury. Bladder
perforation in retropubic slings is a common complication
with a recent meta-analysis reporting rates of 3.2%, [5]
and rates up to 15% have also been reported in at least
one multicenter study [6]. Bowel and vascular injuries
have also been reported, though less frequently than
bladder perforations, but are more serious and have
resulted in patient deaths.
The transobturator approach was first described by
Delorme in 2001 [7]. The major advantage of the
transobturator approach is the avoidance of the retropubic
space, decreasing complicatio ns such as bladder and bowel
perforation, and major vascular injury. Bladder perforation
using the transobturator approach have reported rates as
low as 0%, considerably less than those reported for the
retropubic procedure [5]. Recent studies report that the
transobturator method provides intermediate-term efficacy
results that are comparable to the retropubic method with
a reduction in major complication risks [8-10]. As a
result, the transobturator approach has increased in
popularity for midurethral sling placement in many
centers due to its efficacy and low morbidity.
In keeping with the trend of improving SUI treatment
options (less invasive, more efficacious, safer, improved
recovery), the single-incision method has recently been
introduced. Single-incision slings provide the latest
advance in midurethral tensionless sling technology and
require only one small vaginal incision placed beneath
the urethra. Proposed advantages of the single-incision
method over the retropubic and transobturator are less
postoperative pain and decreased incidence of
complications [11]. Currently however, there is minimal
data available on the long-term efficacy and safety of the
single-incisio n m e t hod [12].
Our experience indicates that many physicians are
hesitant to use the single-incision method as they think
the anchoring results in tensioning that is too tight. The
purpose of the current study was to determine if different
mid-urethral synthetic sling placements were visually
similar regardless of the placement methods, anchor sites,
and tension methods. We also evaluated which sling
placement was tensioned most correctly and was most
likely positioned at th e mid-urethr a. The impetus for this
study was the realization that visually all slings,
regardless of their approach for placement, look fairly
similar after being placed in live patients although the
means of placement may be different.
2. Materials and Methods
Three, fresh female cadavers, with mid-urethal slings
placed by either the retropubic, transobturator, or single
incision method, were used for this investigation. All
three slings used Advantage Mesh from Boston Scien-
tific, USA. Incisions for each of the 3 placement methods
were made on each cadaver so the method of placement
could not be determined by incisions alone. A single
surgeon performed all of the cadaveric sling placements.
This particular surgeon performs over 200 slings each
year. In his own practice, he performed, at the time of
this study in his live patient population, approximately
15% of his slings by the suprapubic approach, 50% by
the obturator approach, and 35% of his slings by the sin-
gle incision approach.
The retropubic sling procedure was performed by
making a 15 mm sagittal incision in the vaginal wall, at
the level of the mid-urethra, followed by a periurethral
dissection plane which was extended laterally toward the
ischiopubic rami. Two stab incisions were made in the
suprapubic region at the upper rim of the pubic bone, 2
cm lateral from the midline. Then, a trocar was placed
within the periurethral tunnel with the tip of the device
between the index finger and the lower rim of the pubic
ramus. The device was pushed upwards with controlled
pressure to exit the suprapubic incision, keeping the tip
of the tunneler in close contact with the pubic bone. The
procedure was repeated on the contralateral side (Figure
1(a)). The synthetic mesh was transferred from the sub-
urethral incision to the skin incisions on each side fol-
lowed by tension-free adjustment using a 12 Hagar dila-
tor as a spacer (Figure 2).
The transobturator technique used was based on
Delorme’s description. 5 An anterior, vertical 15 mm
vaginal incision was made at a point approximately 1 cm
below the urethral meatus. Dissection was then made
laterally toward the ischiopubic ramus. The entry point
was made at the junction of the adductor longus tendon
and inferior pubic ramus. The tip of the trocar was in-
troduced through this incision, initially in a direction
perpendicular to the cadaver, and then oriented upward
and inward in an oblique direction to reach the index
finger introduced in the periurethral space once the ob-
turator muscle and membrane had been punctured. The
introducer was exteriorized from the suburethral incision,
and the tape or the synthetic mesh was transferred from
this site to the skin incision (Figure 1(b)). The same pro-
cedure was performed on the contra-lateral side, and then
tension-free adjustment was set using a 12 Hagar dilator
as a spacer (Figure 2).
For the single-incision method, a 1 to 1.5 cm midure-
thral anterior vaginal wall incision was made. Dissection
was then made up to the inferior pubic ramus on either
side of the urethra. The single incision sling was placed
into the obturator internus muscle using the introducer
and repeated on both sides (Figure 1(c)). The tension of
the single incision sling was set so the sling lay against
the urethra such that pillowing of the periurethral tissues
were observ ed through the por es of the sling.
After placement of each sling, blinding incisions were
complet ed and 30 gynecologis t s and general urologists of
ifferent specializations visually inspected the sling d
Copyright © 2011 SciRes. OJU
Copyright © 2011 SciRes. OJU
(a) (b) (c)
Figure 1. Placement of mid-urethal slings to alle viate stre ss urinary incontinence using the (a) re tropubic; (b) tr ansobturat or;
(c) single incision techniques.
Figure 2. Tension-free adjustment for the retropub ic and transobtu rator techniques was set using a 12 Hagar dilator as a spacer.
1) How was the sling placed? placements. These were experienced surgeons who used
their own experience and knowledge to give their opin-
ion of the sling placement. This study was a visual as-
sessment. The physicians were not able to palpate the
slings. The rationale for not allowing patients to touch
the slings was that if people pulled on the slings then it
may change their position and/or allow people to figure
out how they wer e placed.
a. retropubic
b. obturator
c. single incision
2) Is the sling the right tension?
a. too tight
b. just right
c. too loose
3) Is the sling located at the mid-urethra or bladder neck? Each physician was asked to respond to 3 questions:
3. Results
3.1. Physician Specialization and Characteristics
Reviewing physicians were gynecolgists or general
urologists of varying specializations. The average num-
ber of slings performed each year was 53, with obturator
and retropubic being the most favoured sling types (Ta-
ble 1). Most physicians preferred the obturator or retro-
pubic slings. Markedly fewer physicians used all three
techniques or a combination of obturator plus retropu-
bic/single incision techniques.
3.2. Physician Review
Less than half of the physicians (40%, 43%, 23%; Fig-
ure 3) were able to correctly identify the sling placement
used in each cad aver, and were least likely to id entify th e
single incision sling placement (23%). The single inci-
sion sling, in which the tension was not set with a spacer,
was thought to have the most appropriate tension (73%
tension just right versus 33% retropubic and 47% obtu-
rator). Furthermore, the single incision sling was identi-
fied more often (83%) as placed at the mid-urethra,
compared to the retropubic (50%) and the obturator
(67%) (Figure 3).
4. Discussion
Urinary incontinence is a common problem in adult
women, with SUI the most common form. Treatment
options for SUI in women are designed to prevent the
involuntary loss of urine during increases in intraab-
dominal pressure.
The retropubic sling has reported success rates of 80%
- 89%, but requires blind passage through the retropubic
space, posing risks for bowel injury, bladder injury, ma-
jor vascular injury, and nerve injury [3,4].The tran-
Table 1. Backgroud Information regarding the surgeons
that participated in this study.
Characteristics Reviewing Physicans
N = 30
Specialty, n (%)
General Urology 5 (17)
Gynecology 18 (60)
Urogynecology 7 (23)
Preferred Sling Type, n (%)
Retropubic 11 (37)
Transobturator 13 (43)
Single Incision 2 (7)
Retropubic and Transobturator 1 (3)
Retropubic and Single incisi o n 1 (3)
All Slings 1 (3)
No Preference 1 (3)
Number of Slings Placed per Year
Mean 53
Min 0
Max 200
Figure 3. Physician assessment of sling tec hnique , tension, and placement.
Copyright © 2011 SciRes. OJU
sobturator, by contrast, avoids the retropubic space,
decreasing complications such as bladder and bowel
s being different than the retropu-
ferent than the other c
experience. Taken together, these data seem to initially
dispel some of the previously held misconceptions of
d the single-incision sling as tensioned
. Lose, D. Sykes, et al., “The Prevalence
continence in Women in Four European
he British Association of Urological
93, 2004, pp. 324-330.
ternational Urogynecology Journal and
injuries and is as efficacious as the retropubic method
with a reduction in adverse events [8-10]. Single inci-
sion slings provide the latest advance in midurethral
tensionless sling technology and require only one small
vaginal incision placed beneath the urethra thereby po-
tentially reducing post-operative pain and risk of com-
plications. However, minimal data are currently avail-
able on the long-term efficacy and safety of the sin-
gle-incision method.
Our ex per ie nce h as b een tha t most physicians view the
single incision sling a
c or transobturator slings. Furthermore, physicians of-
ten describe the single-incision as a “tight” sling. This
association of “tight” with the single-incision sling is
based primarily on perceived placement methodology,
and not on actual tensioning tests. For example, the ten-
sion of the single-incision sling is achieved by pushing
the sling into tissue rather than pulling up on it as is do ne
for the retropubic and transobturator slings. When the
coverings are taken off and any spacing devices are re-
moved from the multi-incision slings, there is further
retraction that occurs. Thus, the initial placement of the
multi-incision sling changes and the sling tightens a
small amount. In contrast, placement of the single inci-
sion sling does not change, and the site of the sling dur-
ing tensioning is where it remains. As a result, the sin-
gle-incision sling may seem slightly tighter on initial
placement, but appears the same as the others when the
sling is in its final position.
The purpose of this study was to determine if the sin-
gle-incision sling looks difom-
only used retropubic and obturator slings, and to de-
termine which of the three slings was identified by
trained physicians as being most correctly tensioned at
the mid urethra. The results showed that well-trained,
experienced incontinence surgeons could not visually
differentiate between sling placement methodologies.
Less than half of the physicians (40%, 43%, 23%) were
able to correctly identify the sling placement used, and
were least likely to be able to identify a single-incision
sling placement (23% correctly identified).
Furthermore, the results showed that the single inci-
sion sling was identified as having the most correct
on (73% tension just right versus 33% retropubic and
47% obturator) and the most correct mid-urethral posi-
tioning (83% versus 50%retropubic and 67% obturator).
Of note, 6 physicians who were highly experienced in
sling placement (> 100 procedures/year each). There
were no clear trends in the ability to appropriately iden-
tify the sling placement method used based on physician
how a single-incision sling differs from multi-incision
sling procedures and indicate that the biases toward the
single incision sling typically voiced by practicing phy-
sicians seem to be rooted in preconceived misconcep-
tions and not on actual results, regardless of experience
or specialty.
Conclusions: This study showed that after placement
of a midurethral synthetic sling it is difficult to deter-
mine the placement method used and that most physi-
cians assesse
ost appropriately and most likely positioned at the
5. Acknowledgements
This study was supported by an unrestricted grant from
Boston Scientific.
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