THE TYPE I V-Y ADVANCEMENT THORACODORSAL ARTERY PERFORATOR (T.A.P.) FLAP IN THE TREATMENT OF AXILLARY HIDRADENITIS SUPPURUTIVA.
N.Rehman, R.Y.Kannan, M.S.U.Hassan, N.B.Hart
Department of Plastic Surgery, CastleHillHospital, HullHU16 5JQ, UK.
INTRODUCTION :
Apocrine glands are racemose glands where several glands open into a common pilo-sebacous orifice. Found in the axilla, groin and perineum, they are characterised by the fact that a part of its wall forms its secretions. In hidradenitis suppurutiva, it is thought that keratin plugs block these glands, causing the formation of abscesses which become infected. This forms a vicous cycle of inflammation and scarring which soon spreads to the other glands in this honeycomb to give rise to the stellate appearance of the disease. Eventually, secondary infection sets in, usually Staphylococcus aureus.The actual aetiology for this disease is not known although it is commoner in women and smokers.
The current treatment of hidradenitis suppurutiva is mainly surgical. Initial experiences with excision were not ideal since there were high rates of recurrence. Perhaps this was due to the tendency of the operating surgeon to be lenient with the margin of excision as methods of closure were not adequate. Recently, Soldin et al have shown that excision of all hair-bearing skin in the axilla is sufficient to eradicate the disease while wide excision with a 2 cm margin is excessive. With perforator-based fascio-cutaneous flaps taken from either the posterior arm or the lateral chest wall or both, it is now possible to close these sizeable defects as well provide sufficient soft-tissue bulk to cushion the axillary vessels beneath. Similar techniques had been described in the 1970s but only with a 1:1 ratio since these were not perforator-based.
We have managed to cover these defects without resorting to the equal or unequal double-opposing V-Y advancement flaps ( Types IIA and IIB ). In fact, a single V-Y advancement flap based on the consistent and reliable musculo-cutaneous perforators of the thoracodorsal artery was sufficient to close the defect after removal of all hair-bearing skin down to the axillary vessels in our patients with good results.
PATIENTS AND METHODS :
With the patient in the lateral position and the ipsilateral arm abducted at 90º, two to three perforators along the anterior border of the latissimus dorsi were located using a hand-held Doppler device. Its vascular territory encompasses a quadrilateral area ( figure 1 ) bordered superiorly by the third rib, inferiorly by the seventh rib, posteriorly by the lateral scapular border and anteriorly by the mid-axillary line. A single V-Y advancement flap based on the marked out musculo-cutaneous perforators of the thoracodorsal vessels was planned as shown in figure 2.
All hair-bearing skin in the axilla was then excised down to the axillary vessels (Figure 3). The V-Y flap was dissected sub-fascially beginning anteriorly. Next, the superior border of the flap was elevated and finally its posterior border. Once islanded, sub-fascial dissection gradually released the flap until it was sufficiently lax to close the primary defect. No additional effort was taken to isolate the perforators as the flap advanced comfortably. Once haemostasis was achieved, the flap was closed from below upwards starting with the secondary defect, gradually coaxing the flap into a diamond shape as shown in figure 4. The flap was then inset using subcutaneous and subcuticular absorbable sutures. A single drain was inserted posteriorly.
Perioperative antibiotics were administered for upto a week after surgery. We found that defects of upto 12 x 8 cms could be closed using this technique with sufficient freedom of movement at the shoulder joint. All patients were discharged within 48 hours after removal of the drains and were followed up in clinic.
DISCUSSION :
Several types of local flaps to close these defects have been described. Broadly classified into advancement and transposition flaps, various permutations and combinations have been pieced together.The end result is a significant number of procedures available to the surgeon. The aim here is to perform a simple, convenient, reliable flap to preserve form and function.
V-Y advancement flaps based on perforators have been described before. Niranjan et al described two techniques namely the lateral thoracic perforator based V-Y advancement flap and the double opposing V –Y advancement flap based on the posterior arm and the lateral chest wall perforators. However, the narrow vascular pedicle and the inconsistent course of these perforators make them unreliable. Schwabegger et al have used a similar V-Y advancement flap but based on random perforators and not specifically thoraco-dorsal perforators.
The flap described here is a perforator flap based on the musculocutaneous branches of the thoracodorsal vessels which supply the latissimus dorsi muscle and the skin over the muscle. In our case series, we found no need to dissect down to the thoracodorsal vessels as one would in a typical TAP flap though it is an option for larger defects. Baudet et al showed that this system of vessels was highly reliable being present in all cases with large vessel diameters and easily located. Angrigiani et al first described in 1995, free perforator flaps based on the thoracodorsal artery whilst preserving the latissimus dorsi. Original cadaveric studies show that an axial pattern fascio-cutaneous flap can also be taken on one or two vessels arising as direct septocutaneous branches from the thoracodorsal vessels. Unfortunately, it is present in only 47% of cases and is therefore too inconsistent to base the flap on.
The advantages of the TAP flap over its contemporaries are numerous. It is reliable and reproducible as the subscapular-thoracodorsal arterial system is robust and predictable. Dissecting sub-fascially preserves the fascial plexus thus allowing a length to width ratio of 3:1. The vascular system supplies a large quadrilateral paddle of skin ( shaded area in figure 1 ), allowing it to close large axillary defects. In the longer term, there is no need to immobilize the shoulder and the scar is easily hidden along the posterior axillary fold. Furthermore, it provides excellent colour and texture match to the axillary fossa whilst preserving the axillary folds.
Unlike Schwabegger et al, we have had no need to either include muscle in the flap or to dissect out the perforators to close adjacent axillary defects. This has resulted in a simpler, safer and more user-friendly flap that is the ideal choice of achieving cover after excision of the hair-bearing skin of the axilla as exemplified by our high success rate. As such, we highly recommend its use in clinical practice both in the treatment of axillary hidradenitis suppurutiva and the closure of axillary defects.