Keywords
bipedicle DIEP flap - breast reconstruction - breast cancer - supercharging
Introduction
Breast cancer, earlier believed to be a disease of the West, is now very much an Indian
problem. The latest GLOBOCAN data has shown breast cancer to be the most common cancer
in India.[1] Breast reconstruction is still in a formative stage in the country. As trends change,
we are likely to see more patients demanding and getting breast reconstruction with
autologous tissue and implants. The evolution of autologous flap choice from the abdomen,
pedicle transverse rectus abdominis myocutaneous (TRAM) to free TRAM to free deep
inferior epigastric perforator (DIEP), is likely to be recapitulated in India as it
happened in the world. The most common complication with TRAM/DIEP flaps, fat necrosis
and partial necrosis due to mismatch of flap volume to perfusion, will come to the
fore. The mismatch could be as a result of the native anatomy, excess flap harvest,
or scars due to previous surgery. We present our early experience with achieving negligible
fat necrosis and partial necrosis rates by performing bipedicle DIEP flaps and utilizing
the antegrade and retrograde flow of the internal mammary (IM) vessels. We also utilized
the retrograde flow in a few cases where the supercharging was needed for anterolateral
thigh (ALT) flaps and when antegrade flow was compromised due to fibrosis, nodal involvement,
or inadvertent injury.
Materials and Methods
The study period was from September 2015 to August 2020. All cases of free tissue
transfer for breast reconstruction or chest wall coverage with DIEP, ALT, or gracilis
flap, where the retrograde flow of the internal mammary artery (IMA) and/or internal
mammary vein (IMV) was utilized as a donor vessel, either as the additional second
set of microvascular anastomoses (supercharging and /or super drainage) or for the
first set (primary sole microvascular anastomoses), were included in the study. Data
was kept prospectively in MS Excel, departmental database, and personal logs of the
first author.
Third costal cartilage along with the attached intercostal muscles superiorly and
inferiorly were removed in every case as a standard practice to gain adequate access
to IM vessels. The microvascular anastomoses were performed in this resultant space
under microscope.
Results
In our case series of 35 cases ([Tables 1] and [2]), breast reconstruction was performed in 29 cases with 26 DIEP flaps, two free gracilis
flaps, and one free ALT flap and chest wall reconstruction was performed with six
free ALT flaps. In 34 cases, anastomosis of first pedicle was performed with antegrade
limb of IM vessels and retrograde limb of IM vessels was utilized as source of second
donor vessels either in the form of only donor artery or only vein or both. In one
case, retrograde set was the sole donor vessel. Modes of utilization of IM vessels
are as follows:
-
Both antegrade and retrograde artery and vein ([Fig. 1])
-
Antegrade artery and vein with retrograde artery only ([Fig. 2])
-
Antegrade artery and vein with only retrograde vein only ([Fig. 3])
-
Only retrograde artery and vein ([Fig. 4])
-
Antegrade artery with retrograde vein ([Fig. 5])
-
Antegrade vein with retrograde artery ([Fig. 6])
Table 1
Details of flaps and anastomoses
|
Flap
|
Recipient vessels
|
Donor vessels
|
|
DIEP (26)
• Bipedicle (17)
|
• Bilateral DIEA and DIEV
|
• IMA (antegrade), IMV (antegrade), IMA (retrograde), IMV (retrograde)—16 cases
• IMA (antegrade), IMV (antegrade), IMA (retrograde), cephalic vein—1 case
|
|
o Unipedicle (9)
|
• DIEA, DIEVC1, DIEVC2/SIEV
|
• IMA (antegrade), IMV (antegrade), IMV (retrograde)—5 cases
• IMA (antegrade), IMV (retrograde), cephalic vein—1 case
|
|
• DIEA, DIEVC1
|
• IMA (retrograde), IMV (retrograde)—2 cases
• IMA (retrograde), IMV (antegrade)—1 case
|
|
ALT (7)
|
• Descending branch artery and VC1, transverse/oblique branch artery and VC1
|
• IMA (antegrade), IMV (antegrade), IMA (retrograde), IMV (retrograde)—2 cases
• IMA (antegrade), IMV (antegrade), IMA (retrograde), IMV perforator—1 case
|
|
• Descending branch artery, VC1 and VC2
|
• IMA (antegrade), IMV (antegrade), IMV (retrograde)—3 cases
• IMA (antegrade), IMV (retrograde), cephalic—1 case
|
|
Gracilis (2)
|
• Two pedicle arteries with corresponding VCs
|
• IMA (antegrade), IMV (antegrade), IMA (retrograde), IMV (retrograde)—2 cases
|
Abbreviations: ALT, anterolateral thigh; DIEA, deep inferior epigastric artery; DIEP,
deep inferior epigastric perforator; DIEV, deep inferior epigastric vein; DIEVC1/2,
deep inferior epigastric vena comitans 1/2; IMA, internal mammary artery; IMV, internal
mammary vein; SIEV, superficial inferior epigastric vein.
Table 2
Results
|
Patient characteristics and results
|
|
|
Mean age (years)
|
33.9
|
|
Smoking history
|
0
|
|
Timing of reconstruction
|
|
|
• Primary
|
32/35
|
|
• Secondary
|
3/35
|
|
Histology of disease in primary cases
|
|
|
• Ductal
|
|
|
• Infiltrative disease
|
18/22
|
|
• In situ disease
|
4/22
|
|
• Lobular
|
|
|
• Infiltrative disease
|
1/1
|
|
• In situ disease
|
0
|
|
• Mesenchymal
|
4/4
|
|
• Invasive
|
4
|
|
• Mucinous
|
1
|
|
• No Specific Type
|
3
|
|
Neoadjuvant chemotherapy
|
27/35
|
|
Flaps for reconstruction
|
|
|
• DIEP
|
26/35
|
|
• Bipedicle
|
17/26
|
|
• Unipedicle
|
9/26
|
|
• ALT
|
7/35
|
|
• Gracilis
|
2/35
|
|
Re-explorations
|
2/35
|
|
• Arterial
|
1/35
|
|
• Venous
|
1/35
|
|
• Hematoma
|
0
|
|
Flap complications
|
4/35
|
|
• Total flap loss
|
0
|
|
• Partial necrosis
|
2/35
|
|
• Marginal necrosis
|
1/35
|
|
• Fat necrosis
|
1/35
|
|
Donor site complications
|
|
|
• Dehiscence
• Seroma
|
1/35
|
|
• Purulent collection/mesh associated complication
• Marginal necrosis
|
1/35
|
|
Recipient site complications
|
|
|
• Seroma
|
1
|
|
• Hematoma
|
1
|
|
• Purulent collection
|
1
|
|
• Wound gape
|
2
|
|
• Native flap necrosis
|
2
|
Abbreviations: ALT, anterolateral thigh; DIEP, deep inferior epigastric perforator.
Fig. 1 Both antegrade and retrograde artery and vein. DIEA/V, deep inferior epigastric artery/vein;
IMA/V, internal mammary artery/vein.
Fig. 2 Antegrade artery and vein with retrograde artery only. DIEA/V, deep inferior epigastric
artery/vein; IMA/V, internal mammary artery/vein.
Fig. 3 Antegrade artery and vein with only retrograde vein only. DIEA/V, deep inferior epigastric
artery/vein; IMA/V, internal mammary artery/vein.
Fig. 4 Only retrograde artery and vein. DIEA/V, deep inferior epigastric artery/vein; IMA/V,
internal mammary artery/vein.
Fig. 5 Antegrade artery with retrograde vein. DIEA/V, deep inferior epigastric artery/vein;
IMA/V, internal mammary artery/vein.
Fig. 6 Antegrade vein with retrograde artery. DIEA/V, deep inferior epigastric artery/vein;
IMA/V, internal mammary artery/vein.
Two cases were reexplored, one for suspected venous insufficiency where thrombus evacuation
from venous vasculature was performed and another for suspected arterial insufficiency
where arterial thrombus was evident and evacuation was performed with salvage of both
the flaps. There was partial necrosis in two flaps and marginal necrosis in one flap
where debridement and suturing were performed. One case had fat necrosis with subsequent
infection and purulent discharge with gape. Drainage of pus with antibiotic coverage
was done initially with secondary suturing performed on a later stage. None of the
case had complete flap loss.
Two patients developed seroma and hematoma at the flap site where drainage and evacuation
were performed respectively. Two patients had mastectomy skin flap partial necrosis
that required debridement and suturing. Two patients developed wound gape at the site
of flap inset along with purulent collection in one patient. Both these patients required
secondary suturing later.
Two patients had abdominal donor site complications with only dehiscence requiring
debridement and resuturing in one, while other patient developed purulent collection
with mesh complications requiring exploration under general anesthesia with pus drainage
with mesh removal. Wound wash with negative pressure wound therapy with adequate antibiotic
coverage was done initially with suturing of the wound later. Sample sent for microbiological
studies showed growth of atypical Mycobacterium species.
Discussion
IMAs and IMVs on the antegrade flow are established donor vessels for breast reconstruction
with autologous free tissue transfer or for chest wall coverage. Occasionally, an
additional or alternative set of donor vessels is needed. This situation arises in
the following situations in our study.
-
A bipedicled DIEP ([Fig. 7]) flap is harvested and needs two sets of microvascular anastomoses. The DIEP flap,
in terms of volume and skin, needs to match the defect created by mastectomy or chest
wall resection. In patients where the abdominal pannus is not so abundant or in cases
when the requirement is large, the entire pannus and occasionally extra fat beyond
the pannus needs to be harvested. To match the perfusion of this skin and volume of
the flap, a bipedicle DIEP flap is often needed. In addition to this, need for a bipedicled
flap could also be necessitated by a poor midline crossover perfusion, as per the
native anatomy or due to midline/paramedian scars from previous surgery.
The method we used for the assessment of perfusion to judge the need for a bipedicle
flap consisted of series of steps ([Fig. 8]). This was preceded by a CT angiogram in all cases planned for DIEP flap. The final
decision was based on clinical judgement.
-
Large free ALT ([Fig. 9]) flaps or both free ALT and free tensor fascia latae (TFL) flaps as double free
flaps are sometimes needed for radical mastectomy for recurrent or large primary invasive
ductal carcinoma, malignant phyllodes, or rarer chest wall tumors.[2] Sometimes the large ALT flaps are perfused by multiple perforators arising from
two separate pedicles. In case of combined free ALT and TFL flaps, their use as separate
free flaps requires extra set of vessels for the other flap. To restore the perfusion
of the flap in these cases adequately two sets of microvascular anastomoses are sometimes
needed. The first donor pedicle of choice for these flaps is also IMA and V on the
antegrade flow. The retrograde flow on the distal end can be used as the second donor
vessel set.
-
When gracilis myocutaneous flap ([Fig. 10]) is used for breast reconstruction, sometimes there might be two vascular pedicles
perfusing the muscle and overlying skin and subcutaneous tissue. In cases of doubtful
perfusion from either of the pedicles, both pedicles can be anastomosed.
-
A single set of microvascular anastomoses might also need an alternative donor vessel
in case of gross lymph nodal involvement, fibrosis, thrombosis, or injury precluding
the use of the proximal IMA/V on antegrade flow.
-
A second venous microvascular anastomoses might be desired of the deep inferior epigastric
vein pedicle or the superficial inferior epigastric vein. The distal end of IMV offers
an easily available alternative for drainage.
Fig. 7 Bipedicled deep inferior epigastric artery perforator flap.
Fig. 8 Steps to assess the perfusion.
Fig. 9 Bipedicle free anterolateral thigh flap, two perforators from two different pedicles.
Antegrade IMA/v and Retrograde IMA/V used.
Fig. 10 Vertical upper gracilis flap for whole breast reconstruction.
The second set of microvascular anastomoses, when needed, can be done to a fresh set
of donor vessels (supercharging) or to a branch or runoff of the first set of vessels
(turbocharging). We prefer to supercharge as thrombosis of one vessel will not affect
the other and the size discrepancy between a small branch and larger pedicle is taken
care of.
The distal cut end of IMA/V with retrograde flow is an option, easily available, and
accessible as field of dissection is same as that of the antegrade one. We chose retrograde
limb as second donor set whenever feasible. The other choices for second pedicle were
in the sequence: IM artery perforators, serratus branch of thoracodorsal vessel, thoracodorsal
vessels, thoracoacromial vessels, lateral thoracic vessels, and transverse cervical
vessels. Kanoi et al published their study on IMA perforators being consistent in
anatomical location but their use in free tissue transfer for breast reconstruction
depends on various other factors.[3] All these choices have some problem of either availability, accessibility, expendability,
or caliber of vessel.
The use of the retrograde flow of IMA and V has evolved over the years in a fascinating
way. Earliest use of retrograde limb arose with its anastomosis with posterior descending
coronary artery during coronary artery bypass to relieve blockage in coronary vessels
where antegrade vessel was anastomosed with left anterior descending vessels.[4] The anatomical basis of retrograde flow can be explained by the intricate arterial
and venous communications of thoracic wall. The arterial network is derived mainly
from thoracic aorta. Posterior intercostal and subcostal arteries from axillary artery,
IMA from subclavian artery, and superior intercostal arteries anastomose permitting
collateral circulation.[5] Anterior and posterior intercostal veins being separate vessels, normally draining
in opposite directions, the tributaries of these veins anastomose approximately in
anterior axillary line and due to lack of valves flow can be reversed.[5]
[6]
In a case reported by Hassan et al, TRAM flap was used to perform breast reconstruction
where intraoperatively due to fraility of antegrade IMA, the retrograde end of IMA
was used for anastomosis and resulted in viable and well perfused flap thereby resulted
as a salvage option.[7]
Li et al were the first to study the pressures in antegrade and retrograde limbs of
IM arteries in dogs.[8] Adequacy of pressures flow in antegrade and retrograde limbs was established by
Tomioka et al.[9] Further adequacy of flow in retrograde limbs was validated using intraoperative
color Doppler and indocyanine green angiography by Kerr-Valentic et al[10] and Mohebali et al,[11] respectively. A case series of 10 flaps was performed to study the comparison of
flow rates in antegrade and retrograde veins of IM vessels.[12]
Another case reported by Chan et al where in unilateral breast reconstruction with
stacked DIEP flaps, both the antegrade and retrograde limbs were utilized for two
flaps and they concluded that to increase the volume of reconstructed breast, retrograde
limb of IMA can be used as second donor pedicle if stacking of flaps is done.[13] With this concept of retrograde set of IM vessels utilization, bilateral breast
reconstruction was performed in two cases using single-sided recipient vessels where
opposite-sided pedicle of DIEP was tuned in subcutaneous plane across the sternum
and was anastomosed with retrograde set of IM vessels.[14] Another study done in 250 free flaps for bilateral breast reconstruction using single
set of IM vessels by Opsomer et al documented the adequacy of retrograde limb without
any significant predisposition of flap failure utilizing the same.[15] Retrograde limb of IM vessels is an invaluable option as second set of donor vessels
and adequacy of venous flow can be justified by its valveless system.[6] Utilizing the retrograde flow does not consume any extra time in exposing and dissecting
the vessels as it is already done for the proximal limb antegrade flow.
Most of the breast reconstructions where a bipedicled flap was done and no thrombotic
event happened were uneventful in the late postoperative period with no fat necrosis.
These cases if harvested on a single pedicle would be very high risk for partial necrosis
or fat necrosis.
No imaging was performed to document the patency of vessels. The partial flap necrosis
complications could be attributed to either thrombosis of one of the microvascular
anastomoses or insufficient drainage of a patent microvascular anastomoses.
We do not have a comparator arm as all cases where perfusion was suspect additional
pedicles were anastomosed.
Conclusion
The retrograde flow of the distal cut end of IMA and IMV can be safely used as a donor
vessel for microvascular anastomoses for free tissue transfer for breast reconstruction
or chest wall coverage. The benefit is that it can be safely used for supercharging,
superdrainage, or as the sole donor for microvascular anastomoses in event when proximal
flow IMA/V is unavailable due to gross lymph nodal involvement, fibrosis, thrombosis,
or injury without any consumption of time in dissection of other set of vessels in
the vicinity. Though it might appear counterintuitive, the blood flow rates and direction
are not an impediment to the use of distal cut ends of IMA or IMV. The only disadvantage
that appears is the unavailability of IMA/V for coronary artery bypass in cases where
patient develops coronary heart disease in later age.
