|
Source
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| Plastic
& Reconstructive Surgery
Volume: 98
Number: 4
Sept. 1996 |
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Discussion
The Internal Mammary Artery and Vein as a Recipient
Site for Free-Flap Breast Reconstruction: A Report of
110 Consecutive Cases
by Charles L. Dupin, M.D., Robert J. Allen, M.D., Cynthia
A. Glass, M.D., and Ross Bunch, M.D.
Discussion by William W. Shaw, M.D.
In the early days of breast free-flap surgery, in trying
to identify the best recipient vessels, I had the opportunity
to try nearly all the possible options: thoracodorsal,
circumflex scapular, subscapular, posterior humeral
circumflex, vein grafts to axillary, thoracoacromial,
transverse cervical, and internal mammary vessels. The
internal mammary vessels were used on more than 80 flaps,
mostly for gluteal and some for tensor and TRAM flaps.
Now, after about 500 breast free flaps, I use mostly
the thoracodorsal system and occasionally the internal
mammary system. The authors' extensive and favorable
experience, however, attests to the merit of the internal
mammary vessels. Therefore, the question remains, Is
the internal mammary system better than the thoracodorsal
vessels? If not, when is one system preferable to the
other?
Advantages of the Internal Mammary Over the Thorocordorsal
Vessels
I agree with the various advantages mentioned by the
authors. From my experience, the more important advantages
of the internal mammary vessels are as follows:
- More versatile insetting of the breast flap. By
being able to place the best part of the TRAM flap
on the chest medially, it is easier to achieve medial
fullness. It avoids the annoying situation of having
too much bulk laterally and not enough medially. Also,
with axillary pedicles, the distal part of the flap
is medially on the chest where even minor fat necrosis
can be exasperating to correct, requiring major revision
of the flap.
- Vascular pedicle free from arm and shoulder movement.
The tremendous vertical excursion of the axillary
pedicle caused by movement of the arm and shoulder
is generally not well appreciated. Avoiding the axillary
makes postoperative care easier in cases of tight
pedicle. Without axillary dissection, one tends to
have fewer problems with shoulder stiffness.
- Avoidance of brachial plexus complications. Transient
brachial plexus palsy from axillary exposure is largely
preventable and spontaneously reversible. However,
it can occur easily, causing a great deal of anxiety
for the patient and the surgeon.
- Availability. The thoracodorsal vessels may be compromised
by previous axillary surgery or may be difficult to
dissect from scar tissue. The internal mammary vessels
are always available and previously undisturbed.
- Excellent arterial flow. Because of its proximity
to the heart and its consistent large caliber, the
internal mammary artery always has vigorous pressure.
It appears to be less affected by vasospasm or systemic
pressure changes.
- Surgeon and assistant comfort. When first operating
on the internal mammary vessels under the microscope,
the vessels move up and down as well as go in and
out of focus, making the anastomosis a rather challenging
experience. With some experience and cooperation from
the anesthesiologist, however, it becomes quite manageable.
Operating on the center of the chest rather than reaching
over to the opposite axillae allows the assistant
to participate more easily and comfortably under the
microscope.
Disadvantages of Internal Mammary Vessels Compared
With the Thorocodorsal
- Requires medical chest scar for exposure. With the
standard transverse incision for mastectomy, exposure
of the third or fourth rib at the sternum is not difficult.
With oblique or skin-sparing incisions, the exposure
may be difficult without a more medial incision and
a more visible scar. For patients with subcutaneous
mastectomy, Poland's syndrome, or implant complications
such medial scars would be more objectionable compared
with a well-hidden inframammary scar in conjunction
with a transverse axillary scar.
- Extra time and dissection for immediate reconstruction.
After mastectomy, the thoracodorsal vessels are already
exposed. Without prior scars or radiation, these vessels
are easy to work with and are ready for anastomoses
within minutes. Using the internal mammary vessels,
on the other hand, would require extra time for dissection
of the ribs, intercostal muscles, and finally, the
vessels.
- Delicate internal mammary veins. The internal mammary
veins have much thinner walls compared with the thoracodorsal
veins. Surgical dissection and suturing require greater
attention and expertise. The authors described having
had two veins injured early in their series and having
three venous reoperations for "twisting."
- Compromise of the future availability of the internal
mammary artery for coronary bypass. This may seem
to be a rather remote concern for most patients contemplating
breast reconstruction. We know, however, that many
of these patients will be candidates for coronary
bypass some 20 years later. The 10-year patency of
internal mammary artery bypass is significantly better
than that with vein grafts. Therefore, loss of the
internal mammary artery represents a small but definite
future compromise in some of the patients.
- Need to resect a rib. While a costar cartilage resection
is not risky or difficult, some patients do object
to loss of a rib. There is also the occasional minor
nuisance of the possibility of pneumothorax.
Internal Mammary Versus Thorocodorsal Vessels: Medical
Merits or Fashion?
Medical literature, by nature, favors the reporting
of innovations or new trends. Even surgeons are not
immune to the fashions of the day. Operations have come
and gone out of vogue at different times. Is a routine
switch from thoracodorsal to internal mammary vessels
warranted, or is it merely trendy?
The authors have presented a superb review of the anatomy
of the internal mammary artery and vein. Their work
helped to establish the feasibility and safety of using
the internal mammary vessels. Their description of surgical
techniques is very helpful in making the dissection
easier. As a result of their work, I plan to utilize
the internal mammary vessels more often than in the
past.
On the other hand, my experience with the thoracodorsal
system has been quite good, such that I do not plan
to abandon it in favor of the internal mammary system
routinely. I beg to differ slightly with the authors'
statement that with thoracodorsal vessels, "medial
placement of the breast mound was restricted and lateral
fullness of the flap was a common problem." In
the great majority of my TRAM free flaps, the reach
is not a problem using the thoracodorsal vessels. For
gluteal flaps or other flaps with shorter pedicles,
this may be more important. Also, while the thoracodorsal
artery is usually smaller than the internal mammary
artery, I have found it to be quite satisfactory, as
attested by my result of 99.5 percent survival over
320 TRAM free flaps. My operating time is about 5 1/2
hours for unilateral flaps and 7 1/2 hours for bilateral
flaps, similar to that of the authors. Lastly, many
patients prefer not to have any medial scars that might
be noticeable with low-cut dresses or swimwear.
In the final analysis, this superb study with substantial
clinical experience convincingly supports the authors'
recommendation that the "internal mammary system
should be brought back into the armamentarium for free-flap
breast reconstruction." It would add greatly to
our versatility in breast reconstruction. In some cases,
the choice between the internal mammary and the thoracodorsal
systems may be obvious. In other cases, probably either
option would work equally well. One certainly should
not hesitate to use the internal mammary vessels if
it would make the operation easier or the result better.
Finally, the patient should play an important role in
selecting the location of the scars. I will probably
continue to use the thoracodorsal vessels for immediate
and most TRAM flaps, while choosing the internal mammary
vessels for gluteal flaps, scarred axillae, or cases
with questionable reach of the flap.
In short, it is always nice to have more choices, be
it recipient vessels or the length of skirts.
William W. Shaw, M.D.
Division of Plastic Surgery, UCLA
10833 LeConte Ave. (64-140)
Los Angeles, Calif. 90024
References
Shaw, W. W. Microvascular free flap breast reconstruction.
Clin. Plast. Surg. 11: 333, 1984.
Shaw, W. W., and Ahn, C. Y. Free flap breast reconstruction.
Adv. Plast. Reconstr. Svrg. 9: 221, 1993.
