This study aims to demonstrate that the new generation of the HAPI, the Wireless Perfusion Imager (WIPI) is able to visualise the microcirculation of the abdominal flap and the newly reconstructed breast during DIEP flap breast reconstruction. The…
Source
Brief title
Condition
- Breast neoplasms malignant and unspecified (incl nipple)
- Skin and subcutaneous tissue therapeutic procedures
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main study parameter will be:
The mean perfusion in PU of the newly reconstructed breast correlated to the
occurrence of absence of perfusion-related complications.
Secondary outcome
The secondary study endpoints will be:
1. Visualisation of the perfusion of the abdominal flap during five moments the
measurements will be performed.
2. Applicability and efficiency of the method against motion artefacts.
3. Feasibility and applicability of the WIPI that operates wireless and can
preview perfusion frames in daily clinical practice.
Background summary
1 Breast cancer and breast reconstructions
Breast cancer is responsible for 26% of all malignancies in the Netherlands and
is therefore the most frequently diagnosed malignancy among Dutch females. As
the 10-year survival rate has significantly increased in the last decades due
to improved treatments, surgical decisions regarding the improvement of the
quality of life have become more important. One of the treatments which is
related to a good quality of life is skin-sparing mastectomy followed by breast
reconstruction. Breast reconstructions can be performed with autologous tissue
or with breast implants. Autologous breast reconstructions are superior to
implants regarding the aesthetic outcome, long-term satisfaction and quality of
life. Moreover, autologous breast reconstructions are recommended in case the
remaining breast tissue is of bad quality due to, for example, radiotherapy.
The standard for autologous breast reconstruction is the Deep Inferior
Epigastric Perforator (DIEP) flap reconstruction, referring to the feeding
artery. During this reconstruction, abdominal fat and skin, which are fed by
the aforementioned perforator, are dissected. Subsequently, the DIEP flap is
reconnected to the internal mammary artery.
Fortunately, most patients have a postoperative recovery without any severe
complications. However, perfusion-related complications, such as wound healing
delay or necrosis, are reported to occur in 7%-35% of the patients. Necrosis
could develop in the skin envelope, in the fatty tissue or in the skin of the
transplanted flap. Perfusion-related complications could occur when the
transplanted flap is too large or as a result of thrombosis in the flap or the
pedicle. It is important to reduce these complications to an absolute minimum
as these complications cause a decrease in the patient*s satisfaction and
quality of life. Moreover, necessary revision surgeries lead to the increase of
costs, hospital stay and can lead to serious stress for the surgeon.
2 Current assessment for the microcirculation during DIEP flap breast
reconstruction
Currently, the microcirculation is intraoperatively assessed by the surgeon by
evaluating the skin colour and temperature, capillary refill time and dermal
edge bleeding. However, these methods depend on the surgeon*s experience and
subjective opinion, resulting in potential intra- and inter-observer
variabilities. For a more objective assessment, indocyanine green (ICG)
angiography can be applied for additional evaluation of the perfusion of the
DIEP flap. ICG can give a real-time prediction of the perfusion of tissue that
is going to be transplanted and to make an assessment of the perfusion of the
newly reconstructed breast. The assessment of the perfusion with the use of ICG
is based on the area that becomes green on the angiogram and its intensity
level. The intensity level corresponds to the amount of ICG and therefore to
the amount of blood that perfuses the tissue. The application of ICG has
resulted in a decrease in perfusion-related complications. Therefore, nowadays
in Ziekenhuisgroep Twente (ZGT), the current assessment of the microcirculatory
consists of the combination of the application of ICG and the subjective
assessment of the surgeon.
Nevertheless, ICG has some disadvantages. First, it requires the administration
of a contrast agent. Due to the washout of 20 minutes and a half-life time of
150 to 180 seconds, it takes several minutes after inflow to visualise the
outflow of ICG out of the arterial and venous system. This means that the
intensity signal gradually decreases over time after ICG administration.
However, changes in perfusion after the inflow of ICG due to for example
vasospasm or thrombosis can hardly be visualised as the ICG is already present
in the vascular system. Thus, it is hard to detect an occlusion that is caused
by vasospasms or thrombosis just after the inflow of ICG. Another disadvantage
is that the assessment of the fluorescence intensity does not have a cut-off
value (yet) for under-perfused tissue, which makes the assessment subjective.
Finally, as ICG is a contrast agent that has often to be administered multiple
times during surgery, adverse reactions can occur. However, these are rare and
are reported to develop in 0.2% of the exposed patients.
3 Laser Speckle Contrast Imaging
A promising technique that could overcome the aforementioned disadvantages of
ICG is Laser Speckle Contrast Imaging (LSCI). LSCI is a real-time and
non-contact imaging technique for perfusion measurements. It does not need any
contrast agents, the measurements could take place at any convenient time and
the measurements only take a few seconds. The principle of LSCI is that it uses
backscattered light from tissue that is illuminated with coherent laser light
to create a random interference pattern. This is also known as the speckle
pattern. Moving particles in tissue, for example red blood cells, cause
fluctuations in this speckle pattern, which results in blurring speckles. The
degree of blurring can be correlated to the blood flow, and so to perfusion.
With the use of this technique, perfusion at a depth of about 300 µm can be
visualised. In the skin, this corresponds to dermal microcirculation.
4 Results from previous LSCI studies
In several studies, LSCI is already evaluated and considered as a promising
technique for perioperative assessment of the microcirculation in colorectal
surgery, cerebrovascular surgery and reconstructive surgery. The results in
reconstructive surgery are of particular interest to this study. Zötterman et
al. performed multiple studies regarding the assessment of perfusion in
reconstructive surgery, of which a cut-off value was lacking for under-perfused
tissue. First, their aim was to investigate whether LSCI could be
perioperatively applied to identify areas with compromised circulation and
thereby to predict areas that have a high risk of developing postoperative
necrosis. They concluded that perfusion below 25 Perfusion Units (PU, arbitrary
unit) was a predictor for tissue morbidity within 72 hours after surgery in
porcine flap models. Consecutive research started on the perfusion distribution
and perfusion-related postoperative complications during DIEP flap breast
reconstruction. That study also showed a cut-off value for tissue morbidity,
but this was a cut-off value of 30 PU for postoperative flap necrosis.
However, a limitation of these studies was the use of mounted LSCI devices. Due
to the inflexibility of these devices, it is complicated to use them in the
operating theatre. Therefore, the Biomedical Photonic Imaging group of the
University of Twente is developing a handheld and wireless system. The previous
version of this LSCI system, known as handheld perfusion imager (HAPI), was
applied in the research to psoriasis lesions (NL69174.091.19) and this showed
that handheld measurements give similar visual results compared to mounted
measurements. Even though a statistically significant difference was found
between mounted and handheld measurements because of movement artefacts in
handheld measurements, the handheld device is of additionally clinical value in
terms of comfortability and flexibility for medical staff and patients.
However, the HAPI system still had some disadvantages in terms of manual
postprocessing to correct motion artefacts, which was time-consuming.
Study objective
This study aims to demonstrate that the new generation of the HAPI, the
Wireless Perfusion Imager (WIPI) is able to visualise the microcirculation of
the abdominal flap and the newly reconstructed breast during DIEP flap breast
reconstruction. The hypothesis is that the WIPI is able to detect poor skin
perfusion and that the WIPI is able to demonstrate vasospasms and thromboses
during surgery, which could be missed with the use of ICG. If the hypothesis
holds true, the WIPI could serve as a non-invasive, real-time technique to
identify poor skin perfusion and vasospasms or thromboses where the current
method is not able to do so. This enables early detection of poor skin
perfusion during surgery that might have resulted in postoperative necrosis,
possibly caused by thromboses or a too large flap. However, as this is a proof
of concept study, this study will be limited to the visualisation of the
microcirculation and the eventual correlation between the perfusion and
perfusion-related complications.
In conclusion, our vision is that the WIPI could be used in the future as a
non-invasive technique to visualise poor skin perfusion and thereby minimise
perfusion-related complications in an objective manner. The compactness and
handheld nature of this technique are of particular interest with regard to the
application in the operating theatre.
Study design
Study design:
This is a prospective case series study and a proof of concept study of the
multidisciplinary breast cancer treatment centre in ZGT. The aim is determine
if there are any differences in mean perfusion of the newly reconstructed
breast between two groups: patients that develop perfusion-related
complications and patients that do not develop perfusion-related complications.
The surgeon postoperatively determines whether perfusion-related complications
did occur and its severeness. We will include 40 patients. We will include
patients that will have a unilateral or a bilateral DIEP flap breast
reconstruction. A bilateral DIEP flap breast reconstruction will be described
as two cases. We assume the perfusion in the chosen flaps differ enough from
each other to make two separate cases; the chosen artery and vein for both
flaps will be different in length and diameter. Moreover, the flaps will not
have the exact same size and weight.
Duration of the study:
Patients enrolled in this study will be followed for two months and two days.
Measurements take place during DIEP flap breast reconstruction on day 1, and
the day after surgery on day 2. Thereafter, in the next two subsequent months
information regarding complications after surgery is subtracted from the
electronic patient records. Prior to participating in this study, patients have
to meet inclusion criteria and must be willing to give written informed
consent. There are no pre-established exclusion criteria to participate in this
study.
Settings:
Prior to each measurement, real-time perfusion maps (existing of speckle
images) and colour images will be previewed on the screen of the WIPI by
pushing a button during surgery. A technical physician (in training) will
perform the measurements with the WIPI. The previews make it easier for the
technical physician to check which area of the skin will be scanned at the
current position and if this is according to plan. To make sure the surgeon
will not be influenced by the perfusion maps made with the WIPI, the perfusion
maps will only be visualised on the screen of the WIPI itself and the laptop in
the corner of the operating room. The perfusion maps will not be sent to an
external monitor. The surgeon is not allowed to look at the perfusion maps at
the WIPI or at the laptop during surgery.
After previewing, the actual measurement can start. Some of the measurements
consist of ten scanning moments. During each scanning moment, multiple colour
images and speckle images will be obtained. The front side of the WIPI will be
held at a distance of 30 cm of the skin as this is the focus distance of the
colour camera. Each scanning moment takes ten to fifteen seconds, after which
the data have to be saved and have to be sent to a laptop to visualise the
perfusion maps. The results of each measurement for further evaluation will be
a colour image and an averaged and aligned perfusion map. The measurement
protocol will be applied to each patient and consists of the following five
measurements:
1. Baseline measurement: After anaesthesia, but before the first incision, the
baseline measurement will be performed to get an idea of the perfusion
distribution of the entire flap. As the field of view of the WIPI has a
diameter of about 10.5 cm, ten measurements will be performed to cover the
entire DIEP flap.
2. Raised flap: After the surgeon raised the flap and found the predefined
perforators, (s)he makes the decision which perforator is going to be
transplanted based on ICG angiography and her/his own evaluation. All other
perforators are clamped or cut through. Then, the second LSCI measurement can
take place, which will also be divided into ten scanning moments. This LSCI
measurement forms the reference for the LSCI measurement after breast
reconstruction. It shows what area of tissue the chosen perforator perfuses and
what it should approximately be after reconstruction.
3. Ischemia: After the second LSCI measurement is performed, the blood flow
through the chosen perforator can be stopped using a removable vascular clip,
which results in ischemia. Vascular clips are often used during different types
of surgery for different reasons to temporarily stop the blood flow. By
removing the clip, the blood flow will be restored without any complications.
After one minute of ischemia, the third LSCI measurement will be performed,
again divided into ten scanning moments. This measurement simulates bad
perfusion of the DIEP flap and could therefore be used as a reference for bad
perfusion in the upcoming measurements. When this third measurement is
completed, the vascular clip can be removed and the perfusion will be restored.
Then, the perforator can be cut through to continue the surgery. This way, this
measurement does not increase the time of ischemia.
4. Anastomosis: When anastomosis is accomplished, the surgeon validates whether
the perfusion is good enough with the use of ICG angiography and based on
capillary refill etc. After validation, the fourth LSCI measurement can be
performed. This measurement will be performed to correlate the mean perfusion
(in PU) of the newly reconstructed breast to the outcome of the surgery. The
outcome is the occurrence or absence of perfusion-related complications.
Maximally ten scanning moments are needed to visualise the entire new breast
surface. However, since the new breast has a smaller surface less than ten
scanning moments may be required to image the full surface of the new breast.
In case the perfusion was sufficient during this LSCI measurement, but suddenly
after this measurement, the surgeon does not trust it anymore, the surgeon can
do additional surgical actions to restore the perfusion. An additional LSCI
measurement will then be performed.
5. Postoperative: One day after surgery, the last LSCI measurement will be
performed at the breast, again divided into maximally ten scanning moments.
This measurement will be performed to show if the perfusion in PU differs from
the perfusion in PU during surgery or if the perfusion will approximately be
the same.
Study burden and risks
To date, little is known about the changes in the microcirculatory during DIEP
flap breast reconstruction, which include the effects of thromboses and
vasospasms on the microcirculatory that could result in perfusion-related
complications. With the WIPI, we hope to provide new insights into this device
as an imaging technique for the visualisation of the microcirculatory and
changes within the microcirculatory. We aim to describe eventual differences or
similarities in perfusion between patients that develop perfusion-related
complications and patients that do not develop perfusion-related complications.
By doing this, we hope this study could be a starting point for future research
on the WIPI as a predictor of perfusion-related complications. That would be of
great value, given the non-invasive and easy-to-apply character of the device.
Given the potential advantages of the WIPI during DIEP flap breast
reconstruction in the future, we are of the opinion that participation in this
study with only one postoperative measurement and the application of the
non-invasive imaging technique is legitimate. Scanning the skin with the use of
the WIPI is painless and without any discomfort.
Geerdinksweg 144
Hengelo 7555 DL
NL
Geerdinksweg 144
Hengelo 7555 DL
NL
Listed location countries
Age
Inclusion criteria
- >= 18 years of age
- An indication for a unilateral or bilateral DIEP flap breast reconstruction,
either immediate or delayed
- Patients must be willing to give informed consent
Exclusion criteria
- Patients unwilling or unable to give informed consent
Design
Recruitment
Medical products/devices used
Followed up by the following (possibly more current) registration
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Other (possibly less up-to-date) registrations in this register
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In other registers
Register | ID |
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CCMO | NL80104.100.22 |