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