Aims
of
Study:
For
over
30
years,
it
has
been
recognized
that
the
collagen
in
tissue
when
heated
to
between
60°C to 100°C will denature
and
shrink.
This
characteristic
of
collagen
has
been
used
successfully
in
other
medical
specialties
such
as
orthopedics
and
neurology. It has been proposed that using radio frequency (RF) energy to shrink
the
endopelvic
fascia
using
a
novel
electrosurgical
device
would
result
in
the
elevation
of
the
urethrovesical
junction
which
would
improve
stress
urinary
incontinence
(SUI).
This
study
characterized
the
amount
of
shrinkage,
the
tissue
injury
and
healing
response
following
RF
shrinkage
of
tissue
in
an
animal
model. Since this device is intended to treat SUI, the safety of RF energy
applied
directly
to
the
urinary
bladder
was
also
evaluated.
Methods:
Porcine
peritoneal
fascia
was
used
as
a
tissue
response
model
to
evaluate
injury
and
healing
using
a
low
power
RF
energy
delivery
system
(SURx,
Inc.,
Pleasanton,
CA).
Six
adult
pigs
were
anaesthetised
and
laparoscopically
treated
at
36
separate
sites
of
the
internal
abdominal
wall.
Additionally,
in
four
animals
the
thermal
effect
was
evaluated
on
the
peritoneal
surface
of
the
urinary
bladder.
Animals
also
received
additional
treatments
immediately
prior
to
sacrifice
to
evaluate
acute
thermal
injury
response. Animals were sacrificed at 0, 7, 21, and 42
days.
Histologic
evaluations
were
performed
using
standard
Hematoxylin
and
Eosin
straining
of
Paraffin
embedded
tissue
samples.
Thermal
injury
and
healing
over
time
were
described
using
quantitative
measurement
of
tissue
shrinkage
and
by
measurement
of
depth
of
collagen
denaturation
and
tissue
injury
response.
Results:
Gross tissue shrinkage of 25% to 50% was noted
at
the
time
of
the
procedure.
Degree
of
denaturation
was
quantified
and
depth
of
penetration
was
measured. The average depths of injury repair for treatments
were:
| |
Acute |
7
days |
21days |
42 days |
|
Tissue
response
depth
|
1.0-2.0mm |
2.2mm |
4.5mm |
4.7mm |
Histologic
outcomes
included:
total
reperitonealiztion
of
treatment
site,
acute
followed
by
chronic
inflammatory
changes
and
finally
resolution
of
inflammatory
response
and
chronic
fibrotic
replacement
of
denatured
cell
matrix
with
reabsorption
of
acute
cell
debris
at
30
days
of
longer.
Treatment
of
the
urinary
bladder
surface
resulted
in
rapid
healing
with
no
internal
mucosal
damage
and
no
significant
lesions.
Conclusions:
The use of precisely delivered low power RF energy
shows
substantial
tissue
shrinkage
and
controlled
treatment
depths.
Wound
healing
response
was
comparable
to
that
seen
with
other
more
expensive
or
more
traumatic
surgical
modalities
such
as
laser,
electrosurgery
or
scalpel
approach.
No
adverse
effects
of
this
treatment
on
the
urinary
bladder
were
noted.
RF
tissue
shrinkage
may
hold
promise
for
the
treatment
of
SUI
in
humans.
This
study
supported
by
SURx,
Inc.,
Pleasanton,
CA
USA.
