Trial Information

The Potential Role of the Superficial Inferior Epigastric Vascular System in the Perfusion of Zone IV of Deep Inferior Epigastric Perforator (DIEP) Flaps

- Breast cancer is the commonest cancer to affect women in the UK. Current guidelines
state that; disease permitting, all females due to undergo mastectomy for breast cancer
should be offered reconstruction. Autologous free tissue transfer using abdominal
tissue remains an excellent option for breast reconstruction due the readily available
fatty tissue and the low donor site morbidity. In recent years the trend has been to
base the abdominal tissue on perforating vessels rather than to routinely harvest
muscle along with the flap; thus further potentially reducing donor site morbidity.
Abdominal tissue based upon the Deep Inferior Epigastric Perforator (DIEP) system is a
well recognised option in breast reconstruction.

- This procedure involves harvesting the lower abdominal tissue basing its blood supply
on one of the Deep Inferior Epigastric Perforating Arteries and concomitant veins.
These are branches of the External iliac artery which perforate through the rectus
muscle or the intertendinous intersections.

- A large volume of tissue can be harvested based on a single perforator.

- Hartrampf divided the abdominal tissues into distinct perfusion zones I-IV based upon
their location to the perforating artery. Zone I overlies the perforating vessel, Zone
II is across the midline adjacent to perforating vessel. Zone III is on the ipsilateral
periphery to the perforating vessel and Zone IV is on the furthest periphery on the
contralateral side from the perforator. Over the years this has undergone debate and
many have advocated that zones II-III (according to Hartrampfs original classification)
should be switched. However everyone remains clear on the term Zone IV. Zone IV is
classically the area of the flap which receives least perfusion/drainage from the
perforating vessels and as such is most liable to undergo congestion and tissue
ischaemia leading to fat/skin necrosis. As such many surgeons routinely excise zone IV
from the DIEP flap prior to transfer to the chest defect. This obviously leads to a
reduction in the volume of tissue available for reconstruction.

- Classically most problems with zone IV / flap perfusion tend to be related to venous
congestion.

- Many surgeons advocate the use of the superficial inferior epigastric vein as a
"lifeboat" vessel in salvaging a congested DIEP and have published their results in
doing so.

- There are however no in-vivo studies showing the full contribution of the superficial
vascular system in flaps based primarily upon the Deep Inferior Epigastric Perforating
Vessels. A recent study using preoperative CTs has shown that there are
"macrovascular-shunts" between the deep arterial system and the superficial venous
system but the implications of this have yet to be established.

- Fluoroscopy using indocyanine green is an established method at looking at tissue
perfusion in free flaps.

- Laser Doppler imaging is another well described technique for the monitoring /
assessment of tissue perfusion in plastic surgery operations.

- By further understanding the perfusion of the DIEP flaps the investigators hope to
improve flap survivability and also the volume of flap which can be used.

- Patients due to undergo breast reconstruction with a free DIEP flap by the senior
researcher/surgeon will be identified.

- On the day of their operation the DIEP flap will be raised as normal on one of the DIEP
arteries from either side. The superficial vascular system will be dissected free on
the contralateral side.

- The flap will then be scanned with Laser Doppler Imaging and then the SPY scanner
(indocyanine green angiography coupled with fluoroscopy)

- This will take place in a randomized fashion as follows

- Superficial Inferior Epigastric Artery Clamped; Vein Unclamped

- Superficial Inferior Epigastric Artery Unclamped; Vein Clamped

- Both Artery and Vein Clamped

- Both Artery And Vein Unclamped

- There will be a 5minute pause between each intervention to allow perfusion to
stabilize. Previous research (awaiting publication) within our department has shown
that this is the necessary amount of time to allow stabilization.

- The scanning period will be carried out during the natural rest break of the operating
surgeon and as such will not add significantly to the length of the procedure.

- Once the scanning process is finished the operation will then proceed as standard with
DIEP flap being disconnected from the abdomen and reconnected in the chest to
reconstruct the breast.