Breast Conserving Surgery - Tissues Back
The ‘pedicled’ Latissimus Dorsi musculocutaneous Flap (LD flap)
The Latissimus Dorsi (LD) flap was first described for autologous breast reconstruction in 1977. It consists of part or all of the largest muscle of the back, the latissimus dorsi muscle (fig. 1) together with an island of overlying skin and fat, which can be designed in a variety of shapes and directions (Fig.2a). Through a tunnel underneath the armpit, the flap can be transferred onto the breast or chest wall (fig. 2b). The blood vessels supplying the muscle and overlying skin, originate at the top of the axilla and are called the thoracodorsal artery and vein. These vessels are not divided during surgery and the tissue remains attached at all times. This flap is therefore described as ‘pedicled’, as no microsurgery is required. It is a relatively safe and simple procedure, with satisfactory cosmetic results.
|Fig. 1: the muscles of the back||Fig. 1: the latissimus dorsi muscle|
|Fig. 2a||Fig. 2b|
Fig. 1: The Latissimus Dorsi (LD) muscle, the largest and strongest muscle of the back. Fig. 2: The Latissimus Dorsi (LD) flap is supplied by large nourishing blood vessels from the arm pit and can be transferred onto the breast or chest, with an island of overlying skin and fat.
The ‘pedicled’ ThoracoDorsal Artery Perforator Flap (TDAP flap)
This flap is very similar to the LD flap, the main difference being that the latissimus dorsi muscle is separated in the line of its fibres to find the perforating (feeding) blood vessels. No muscle or major nerves are sacrificed. The latissimus dorsi remains in its original position and only the island of skin and fat is transferred. This is known as the ThoracoDorsal Artery Perforator (TDAP) flap) (Fig.3) and the latissimus dorsi muscle function is completely preserved.
|Fig. 3a||Fig. 3b||Fig. 3c|
Fig. 3: The ThoracoDorsal Artery Perforator (TDAP) flap: the latissimus dorsi fibres are separated during surgery but the muscle itself is left in place. Only an island of skin and fat from the back are transferred, together with the perforating (feeding) blood vessels.
Both of these techniques allow reconstruction of quite substantial breast defects, especially in the central and outer breast quadrants. Removing part or all of the latissimus dorsi muscle can affect shoulder function in physically active people, whereas this is completely preserved by a TDAP flap. The transfer of the TDAP flap onto the breast is unfortunately limited by the length of the blood vessels that supply it from the axilla, so it can only be used for reconstruction of quite laterally placed defects. Reconstruction of an entire breast using these flaps usually necessitates the addition of an implant to achieve sufficient volume.
The main advantage of transferring tissue from the back in breast reconstruction is that the operation is less complex in comparison to microsurgical free tissue transfer. The disadvantages include an insufficient amount of tissue for complete breast reconstruction and the possibility of an unsatisfactory donor site scar. If a large amount of skin and fat are transferred, the contour of the back may be affected, leading to asymmetry. The color and texture of the skin from the back is also different from the breast. Finally, sensation cannot be restored and involuntary contraction of the transferred muscle may sometimes be problematic.
|Fig. 4a||Fig. 4b|
|Fig. 4d||Fig. 4e|
Fig. 4: Pre-operative (a) and 3 year Post-operative pictures (d, e) of a patient who underwent an upper-outer quadrantectomy of her right breast (b), combined with an immediate pedicled TDAP flap (c).A small skin island can be seen in the anterior axillary fold, allowing flap evaluation and monitoring after surgery.
The main indications for the LD or TDAP flap are:
- to restore the anterior axillary fold
- to fill defects in the outer quadrants of the breast
- to cover exposed implants