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During the last decade the concept of perforator flap surgery has greatly refined reconstructive microsurgery in general and reconstructive breast surgery in particular. Harvesting a flap without sacrificing the underlying muscle or the functional motor nerves characterizes this technique. Perforator flaps aim to reduce donor-site morbidity to an almost absolute minimum, respecting one of the main adagio's in medicine: primum non nocere. Pedicled perforator flaps have not yet been commonly used or widely described for breast reconstruction. Although the thoracodorsal and intercostal arteries provide many perforators to the region of the back, only the latissimus dorsi muscle or musculocutaneous flaps are in common usage in breast surgery, despite resulting in loss of the largest muscle in the body. Pedicled perforator flaps are a relatively new concept, not yet in wide usage for breast reconstruction. Our clinical experience using pedicled perforator flaps in breast surgery will be presented.
Angrigiani et al1 first described harvesting a cutaneous island of the latissimus dorsi flap without the muscle based on one cutaneous perforator. In our department, the thoracodorsal artery perforator (TDAP) flap is widely used as free flap for large defects on extremities.2,3 However, the use of TDAP or other pedicled perforator flaps for breast reconstruction is still limited to few clinical reports. The latissimus dorsi (LD) is largely used in breast surgery, which results in the sacrifice of one of the most important muscles for shoulder function. We described an algorithm of using pedicled perforator flaps in breast surgery, which spares the LD muscle.4 The purpose of this article is to give an update of the technique and the outcome.
The majority of patients with breast or thoracic defects are suitable candidates for pedicled perforator flaps instead of the formerly used LD musculocutanous flaps:
Damage to the thoracodorsal pedicle (e.g., due to previous axillary clearance) is an absolute contraindication to raising a TDAP flap, as it is for a traditional LD flap. In this case, however, a perforator flap based on intercostal vessels may still be harvested for lateral defects on the breast. Previous surgery to the axilla or lung (lateral thoracotomy) or radiotherapy to the region may also result in damage to the perforator complexes.
Defects located at the inferomedial quadrant of the breast are difficult to reach using a pedicled perforator flap. However, some defects can be reconstructed by pedicled perforator flaps based on the anterior thoracic vessels such as intercostal or superior epigastric vessels.
Any partial breast defect accompanied by severe and extended postirradiation damage presents a challenging surgery associated with a high complication risk; therefore, a free-flap technique can be a better option because it provides a larger amount of healthy tissue with its blood supply.
Large breast defects in thin patients are often difficult to reconstruct with pedicled perforator flaps due to a lack of sufficient flap volume.
The blood supply to the LD muscle is well documented. The thoracodorsal (TD) vessels are the main pedicle of the LD muscle. After giving the serratus anterior (SA) branch, the TD vessels divide into two branches, the descending or vertical branch and the horizontal branch. These branches give numerous perforators to the skin. Anatomic studies on cadavers have shown that the vertical intramuscular branch provides two to three cutaneous perforators.1,5,6 The largest perforator pierces the muscle and usually enters the subcutaneous tissue ~8 cm below the posterior axillary fold and 2 to 3 cm posterior to the lateral border of the muscle. In our cases, the perforators are usually found within 5 cm of the anterior border of the LD muscle and between 7 and 10 cm caudally from the posterior axillary line. Our clinical experience with the TDAP free flap showed that a direct perforator of thoracodorsal TD arising around the anterior border of the LD muscle into the skin could be found in some cases, which made the dissection much easier and quicker, but the pedicle is shorter and the flap may not be able to reach distant defects.
The intercostal vessels were described in Kerrigan and Daniel's study7 and various musculocutaneous flaps were harvested based on the intercostal vessels. It was Badran and El-Helaly8 who first described harvesting fasciocutanous intercostal flaps without including the underlying muscles. Using the intercostal artery perforator; flaps in breast surgery has recently been reported by our studies.9 The intercostal perforators can be found anterior to the LD border, making the flap dissection possible without disturbing or sacrificing the TD vessels. These perforators pierce the serratus muscle and turn medially, running above the LD muscle, and are usually accompanied by a sensate branch to the skin of the back. Following our anatomic study, the largest perforators that may used for breast surgery are encountered in four to five intercostal spaces. Their distance form the anterior border of the LD muscle ranges between 0.8 and 3 cm.
A vascular connection between the intercostal perforators and the SA branch is found in 37% of cases. This connection allows harvesting the intercostal perforator flaps but with the SA as a main pedicle.
The pedicled perforator flaps commonly used for breast or thoracic reconstruction are the TDAP flap, the intercostal artery perforator (ICAP) flap, and the serratus anterior artery perforator (SAAP) flap.
Sometimes, a segment of LD muscle may need to be included in the flap due to anatomical variations. Muscle-sparing thoracodorsal (MS-LD) flaps are classified as follows4:
The ICAP flaps are classified as follows9:
Obviously, only the LICAP and AICAP flaps have clinical application in breast surgery.
The patient is always marked before surgery. Breast size, tumor size, tumor location, and the estimated defect size are all taken into account. The thickness of the skin and fat of the back is determined with a pinch test. Doppler examination is performed with the patient lying in a lateral position, similar to that during surgery, with the arm abducted to 90 degrees.
A 5- to 8-mHz handheld Doppler probe allows accurate localization of the perforator. The flap is designed to include the located perforators and lies in the direction of the lines of relaxed skin tension (or bra line). To include any direct perforators, the flap should always extend over the anterior border of the LD. The width of the flap is determined by the size of the defect and the possibility for primary closure of the donor site. More recently, the spiral multidetector computed tomography scan has been introduced to evaluate the skin vascularization.10 This new technology is revolutionary in understanding the vascular anatomy and moreover, planning perforator flaps.
The patient is positioned in lateral decubitus with the arm abducted to 90 degrees. Skin and subcutaneous tissue are incised down to the level of the muscle fascia; the initial dissection can be beveled outward if more flap volume is desired. Flap elevation proceeds from distal to proximal and from medial to lateral at the level just above the LD muscle fascia until the preoperatively identified perforators are located. Dissection of the perforator is done in the standard way as in every standard type of perforator flap. Wide exposure by muscle splitting is mandatory to free the perforator and to clip the side branches. The dissection is done toward the main pedicle to obtain adequate pedicle length for flap transfer.
Dissection of a perforator originating from the descending branch of the thoracodorsal pedicle is easier because fewer branches of the thoracodorsal nerve are encountered and also the intramuscular vessel course is usually shorter. A perforator should be visibly pulsatile. If the surgeon is satisfied with the caliber and the quality of the perforator complex and committed to harvesting the perforator flap, the perforator vessel is fully dissected. However, if the perforators are small but visibly pulsatile, a muscle-sparing technique (MS-LD I) is used to harvest the flap. In this case, the perforators will be dissected within the split LD muscle but not within the muscular part incorporated into the flap. Thus multiple small perforators are included in a 2- to 4-cm cuff of LD muscle and sustain the type I muscle-sparing flap.
If only numerous small nonpulsatile perforators are available, then the flap should be converted to a type MS-LD II flap, containing a bigger piece (up to 5 cm) of muscle, to incorporate the maximum number of perforators within the flap.
Once dissection of the vessels is complete, the skin paddle is carefully passed through the split LD muscle, then subcutaneously through the axillary region into the breast defect.
The donor site is closed primarily. The patient is then turned into a supine position and the flap is inset into the defect and shaped. The flap is either partially or totally de-epithelialized depending on the nature of the defect. The pliable perforator flap easily lends itself to being folded as required to fill the defect.
When ICAP flaps are indicated, an intercostal perforator may be identified and dissected to its origin from the intercostal bundle through the split SA muscle. An intercostal nerve may be included in the ICAP flap, which is therefore raised as a sensate flap. Dissecting the pedicle within the periosteum under the rib lengthens the pedicle but is technically more difficult. The ICAP flap is transferred to the breast defect similarly to the TDAP flap.
If an appropriately sized perforator is identified in front of the anterior border of the LD, it can be dissected and followed back to the major nutrient artery. If the perforator is based on the artery to SA, the flap is raised by dissecting the pedicle within the fascia of the SA muscle. Side branches to the muscle are ligated and care taken to avoid damaging nerve branches.
A selection algorithm for pedicled perforator flaps in partial breast reconstruction is presented in Fig. Fig.11.
Over the past 6 years, 101 pedicled perforator flaps have been used in our department for breast or thoracic reconstruction. The main indication was for immediate partial breast reconstruction (Figs. 2–6). Good breast contour and high patient satisfaction can be obtained using pedicled perforator flaps. Furthermore, there is only minimal decrease in flap volume postoperatively as opposed to the LD musculocutaneous flap, which can lose up to 30% of volume secondary to muscle atrophy.
The average flap size was 20×8 cm (range of length 16 to 25 cm and width 6 to 10 cm). The mean operative time was 2.5 hours (range 1.5 to 3 hours). In 95% of cases, the flaps based on a single perforator. In 8% of cases the perforator flaps were converted to muscle-sparing LD flaps.
Pedicled perforator flaps became our first choice in almost every partial breast reconstruction, resulting in an improved functional and aesthetic outcome for the patient.4 Breast autologous augmentation is the second large indication of pedicled perforator flaps.11 Patients who have a fat-skin access at the lateral axillary region, in particular those who had bariatric surgery with massive weight loss, are good candidates for these techniques.
Muscle preservation is a sound rationale and is likely to contribute to reduced donor-site morbidity. Donor-site morbidity after raising a pedicle perforator flap is reduced to an absolute minimum as the LD muscle is left intact with functional motor innervation.
Perforator flap surgery is initially more difficult than traditional myocutaneous LD flap harvest. This kind of challenging but ultimately fulfilling surgery necessitates some training with the attendant learning curve. Significantly there was no seroma formation at the pedicled perforator flap donor site.4 Patients were also less likely to complain of pain and appeared more comfortable after pedicled flaps, although this was not assessed objectively.
Another important consideration in selecting pedicled perforator flaps is the potential to harvest the LD muscle flap at a later date. This is evident in the case of the ICAP flap where the thoracodorsal pedicle is not disturbed. In the case of the pedicled TDAP or SAAP flap, it is dependent on the length of pedicle being used. Clinical experience with pedicled perforator flaps increased dramatically and more studies from different centers are encouraged.12
Pedicled perforator flaps are an additional tool in the armamentarium of the reconstructive breast surgeon, and we suggest that they should be considered whenever an adequate perforator is encountered. Safe and reliable harvest of these flaps requires a thorough knowledge of the anatomy of the various perforator flaps and expertise in perforator flap surgery.