Drug treatment and flap survival

Some investigators found that isoxsuprine, propranolol, or heparin would increase skin-flap survival in loose-skinned animals. We evaluated the effects of these three drugs in the pig, an animal with skin circulation similar to that of humans. Four hundred ventrally based skin flaps that have a proximal axial portion and a distal random portion were made on the flanks of 40 pigs. There were eight study groups: control, isoxsuprine preoperatively and postoperatively, propranolol preoperatively and postoperatively, isoxsuprine postoperatively only, propranolol postoperatively only, heparin, single-stage surgical delay, and two-stage surgical delay. Flap survival was improved by the two-stage surgical delay when compared with the control flaps, flaps from pigs receiving a drug, or flaps from pigs having a single-stage surgical delay (p less than 0.001). When compared with the control flaps, neither isoxsuprine, propranolol, heparin, nor single-stage surgical delay significantly increased flap survival.     

Pharmacologic action of isoxsuprine in cutaneous and myocutaneous flaps

The therapeutic effects of isoxsuprine on skin capillary blood flow and viability were studied in arterial buttock flaps, latissimus dorsi myocutaneous flaps, and random skin flaps in pigs. It was observed that parenteral isoxsuprine increased capillary blood flow to the skin of arterial buttock flaps and the skin and muscle of latissimus dorsi myocutaneous flaps in a dose-response manner, with a maximum vascular effect observed at 1.0 mg/kg. However, this maximum effective dose of isoxsuprine did not have any significant effect on skin viability in the cutaneous and myocutaneous flaps compared with the control. Examination of the distribution of capillary blood flow within the flaps at varying distances from the pedicle revealed that isoxsuprine did not increase capillary blood flow or perfusion distance in the distal portion of the skin of arterial buttock flaps, latissimus dorsi myocutaneous flaps, and random skin flaps. The increased capillary blood flow as a result of isoxsuprine treatment was limited only to the arterial portion of the arterial buttock flaps and latissimus dorsi flaps. Therefore, it is concluded that isoxsuprine alone is not effective in augmentation of skin viability in cutaneous and myocutaneous flaps. The pharmacologic action of isoxsuprine on the vasculature in the skin and muscle of flaps was also discussed.     

Prevention of necrosis in island myocutaneous flaps in the pig by treatment with isoxsuprine.

Experimental gracilis myocutaneous flaps were designed in the pig which consistently resulted in 81 cm2 of surviving tissue and 194 cm2 of necrotic tissue. When these same flaps were raised in animals treated for two weeks preoperatively and 6 days postoperatively with isoxsuprine, there was 100 percent survival in all (8) flaps.     

Prevention of muscle necrosis in an experimental neurovascular island muscle flap by a vasodilator drug--isoxsuprine.

We report an experiment that demonstrates one means to prevent necrosis in an experimental island muscle flap. The results imply that necrosis of skeletal muscle in a clinical flap could be prevented by treatment with isoxsuprine.     

The expansive gluteus maximus flap

The rich vascular network of the gluteal and posterior thigh region provides for a larger range of flaps for reconstructive surgery than previously described. Facility with these flaps requires an appreciation of relevant anatomy, embryology, and anthropology. Structural changes in the gluteus maximus muscle are critical to the evolutionary advance toward an upright stance during walking. The superficial and deep segmentation of the gluteus maximus are best appreciated by phylogenic and ontogenetic study. Femoral arterial and gluteal arterial anastomotic hemodynamics are affected by the relative involution of the gluteal system in late embryogenesis. The gluteal thigh flap should include contributions from the femoral system when the cutaneous branch of the inferior gluteal artery cannot be identified. Huge sacral wounds can be closed with gluteus maximus myocutaneous flaps with maintenance of muscular function by detaching the entire origin, sliding the muscle medially, and reconstructing these attachments. By dissection between the divergent inserting fibers of the gluteus maximus, a long, superficial portion of the muscle can be raised that forms the basis of the extended gluteus maximus flap. The pedicle of the flap is at the level of the piriformis muscle and the skin paddle can be placed over the midportion of the posterior thigh. Finally, the first deep femoral perforating artery forms the basis of a posterolateral fasciae latae flap that is well suited for coverage of defects over the trochanter.     

Increased survival and vascularity of random-pattern skin flaps elevated in controlled, expanded skin

Controlled clinical tissue expansion, a new technique of providing donor tissue, results in an increase in surface area of expanded skin. The aim of the present study was to determine the effect of controlled tissue expansion on the surviving lengths of random-pattern skin flaps elevated in expanded tissue. In five pigs the surviving lengths of flaps raised in skin expanded for 5 weeks using a 250-cc rectangular Radovan-type tissue expander were compared with the survival lengths of flaps elevated in tissue in which a similar prosthesis was not expanded, bipedicle flaps delayed for 5 weeks, and control acutely raised random-pattern flaps. The expanded flaps had a mean increase in surviving length of 117 percent over control flaps, which was statistically significant. The delay flaps had an increase in survival of 73 percent over control flaps, which was also statistically significant. There was no significant difference in survival between expanded flaps and delayed flaps. Morphologic studies using radiographic techniques on one pig demonstrated increased vascularity with tissue expansion. The results of this work demonstrate that in addition to providing increased surface area with controlled expansion, flaps raised in expanded skin have a significantly augmented surviving length. The mechanism for this increased vascularity with expansion is not known at this time, but it may be due to physical forces associated with expansion acting as a stimulus for angiogenesis.     

Surgical augmentation of skin blood flow and viability in a pig musculocutaneous flap model

A porcine rectus abdominis musculocutaneous (TRAM) flap model was designed and validated in nine pigs. This TRAM flap was based on the deep inferior epigastric (DIE) vessels with an 8 x 18 cm transverse skin paddle at the superior end of the rectus abdominis muscle. The model was subsequently used to test our hypothesis of surgical augmentation of flap viability by vascular territory expansion. Specifically, we observed that ligation of the superior epigastric (SE) vessels at 4, 7, 14, and 28 days (N = 6 to 8) prior to raising the TRAM flaps significantly increased (p less than 0.05) the length and area of the viable skin in the transverse skin paddles of the treatment flaps compared with the contralateral shammanipulated control flaps. This significant increase in skin viability was seen to be accompanied by a significant increase (p less than 0.05) in skin and muscle capillary blood flow in the treatment TRAM flaps compared with the controls (N = 9). The mechanism of vascular territory expansion is unclear. We postulate that hypoxia resulting from the ligation of the superior epigastric vessels prior to the flap surgery may play a role in the triggering of the deep inferior epigastric artery to take over some of the territory previously perfused by the superior epigastric artery. This would then increase the skin and muscle capillary blood flow in the transverse paddle when the TRAM flap was raised on the deep inferior epigastric vascular pedicle.     

The adductor flap: a new method for transferring posterior and medial thigh skin

Skin flaps from the medial aspect of the thigh have traditionally been based on the gracilis musculocutaneous unit. This article presents anatomic studies and clinical experience with a new flap from the medial and posterior aspects of the thigh based on the proximal musculocutaneous perforator of the adductor magnus muscle and its venae comitantes. This cutaneous artery represents the termination of the first medial branch of the profunda femoris artery and is consistently large enough in caliber to support much larger skin flaps than the gracilis musculocutaneous flap. In all 20 cadaver dissections, the proximal cutaneous perforator of the adductor magnus muscle was present and measured between 0.8 and 1.1 mm in diameter, making it one of the largest skin perforators in the entire body. Based on this anatomic observation, skin flaps as large as 30 x 23 cm from the medial and posterior aspects of the thigh were successfully transferred. Adductor flaps were used in 25 patients. On one patient the flap was lost, in one the flap demonstrated partial survival, and in 23 patients the flaps survived completely. The flap was designed as a pedicle island flap in 14 patients and as a free flap in 11.When isolating the vascular pedicle for free tissue transfer, the cutaneous artery is dissected from the surrounding adductor magnus muscle and no muscle is included in the flap. Using this maneuver, a pedicle length of approximately 8 cm is isolated. In addition to ample length, the artery has a diameter of approximately 2 mm at its origin from the profunda femoris artery. The adductor flap provides an alternative method for flap design in the posteromedial thigh. Because of the large pedicle and the vast cutaneous territory that it reliably supplies, the authors believe that the adductor flap is the most versatile and dependable method for transferring flaps from the posteromedial thigh region.     

Pharmacologic enhancement of rat skin flap survival with topical oleic acid

This study was instituted to investigate in a rat model the effect of topical coadministration of the penetration enhancer oleic acid (10% by volume) and RIMSO-50 (medical grade dimethyl sulfoxide, 50% by volume) on rat skin flap survival. A rectangular abdominal skin flap (2.5 x 3 cm) was surgically elevated over the left abdomen in 40 nude rats. The vein of the flap's neurovascular pedicle was occluded by placement of a microvascular clip, and the flap was resutured with 4-0 Prolene to its adjacent skin. At the end of 8 hours, the distal edge of the flap was reincised to gain access to the clips and the clips were removed. After resuturing of the flap's distal edge to its adjacent skin, the 40 flaps were randomly divided into four groups. Group 1 (control) flaps were treated with 5 g of saline, group 2 (dimethyl sulfoxide) flaps were treated with 2.7 g of dimethyl sulfoxide (50% by volume), group 3 flaps (oleic acid) were topically treated with 0.45 g of oleic acid (10% by volume), and group 4 (dimethyl sulfoxide plus oleic acid) flaps were treated with a mixture of 0.45 g of oleic acid (10% by volume) and 2.7 g of dimethyl sulfoxide (50% by volume) diluted in saline. Each flap was topically treated with 5 ml of drug-soaked gauze for 1 hour immediately after clip removal to attenuate reperfusion injury. Thereafter, drug was applied topically once daily for 4 more days. Digital photographs of each flap were then taken on day 6 and the flaps were then harvested. The percentage of skin survival in each flap was determined by computerized morphometry and planimetry. The mean surviving area of group 3 (oleic acid-treated flaps) was 23.60 +/- 4.19 percent and was statistically higher than that in group 1 (control, saline-treated flaps) at 7.20 +/- 2.56 percent. The mean surviving area of group 2 (dimethyl sulfoxide-treated flaps) at 18.00 +/- 5.23 percent and group 4 (oleic acid- and dimethyl sulfoxide-treated flaps) at 9.90 +/- 3.44 percent did not achieve statistically higher mean surviving areas than controls. A topical solution of oleic acid (10% by volume) caused a statistically significant increase in the survival of rat abdominal skin flaps relative to controls. Dimethyl sulfoxide and the two experimental drugs together did not increase the percentage of flap survival when given as a single 5-ml dose released from a surgical sponge at reperfusion for 1 hour and then daily for a total of 5 days. The reasons for the lack of response are unknown but may have included the technical difficulty of delivering an adequate dose of dimethyl sulfoxide topically and immiscibility between dimethyl sulfoxide and oleic acid. Further studies may be warranted.     

Myocutaneous flap ischemia: flow dynamics following venous and arterial obstruction.

To further clarify the pathogenesis of the poorer prognosis in skin flaps exposed to venous stasis compared with arterial insufficiency, a microsphere study was conducted in bilateral rectus abdominis island flaps in seven pigs. The relationship between capillary blood flow and arteriovenous (A-V) shunting was studied during progressive 1-hour intervals of arterial insufficiency and venous stasis and during 3 hours of reperfusion. Under controlled conditions, total blood flow was reduced from 100 percent to both 50 and 25 percent by application of an adjustable clamp on the artery supplying one flap and on the vein draining the contralateral flap. The relative distribution between A-V shunt flow and capillary blood flow was different in arterial insufficiency when compared with venous stasis at both the 50 percent and the 25 percent blood flow levels. In the arterial insufficiency flaps, the A-V shunt flow and capillary blood flow shared the total blood flow in the following percentages: 64/36 (at 100 percent total blood flow), 44/56 (at 50 percent total blood flow level), and 22/78 (at 25 percent total blood flow level). In the venous stasis flaps, the A-V shunt flow and the capillary blood flow shared the total blood flow in percentages of 70/30, 66/34, and 55/45, respectively. Hence, in arterial insufficiency flaps, capillary blood flow was spared by a relatively greater decline in A-V shunting compared with venous stasis flaps. Redistribution of capillary blood flow from subcutaneous tissue to muscle was observed, whereas blood flow was equally distributed throughout the length of the flaps at all flow levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

The thin latissimus dorsi perforator-based free flap for resurfacing

The authors present their experience with "thin" latissimus dorsi perforator-based free flaps for resurfacing defects. Perforator-based free flaps have been used for various kinds of reconstruction by presenting important donor structures. The thin latissimus dorsi perforatorbased free flap included only the skin and superficial adipose layer to reduce its bulkiness by dissection through the superficial fascial plane. This flap was used in 12 clinical cases, without flap necrosis or other serious postoperative complications. All of the patients were examined by preoperative power Doppler ultrasound in the spectral Doppler mode to search for the most reliable perforator. This noninvasive ultrasound technique determines the exact location and course of and ensures the reliable flow of the perforators; therefore, it greatly assists microsurgeons in saving operation time and in selecting the most suitable design for perforator flap reconstruction. We used perforators that were identified several centimeters from the lateral border of the latissimus dorsi muscle. The thin flap dimensions could be safely designed for flaps measuring up to 20 cm in length and 8 cm in width for primary closure of the donor site. Generally, a long pedicle is not required for resurfacing reconstructions, where small recipient arteries in the bed are acceptable for anastomosis with pedicles. However, pedicle dissection to the proximal vessels through the latissimus dorsi muscle was required when it was necessary to match the recipient vein for anastomosis. The authors conclude that this thin latissimus dorsi perforator-based free flap has great potential for resurfacing because of its constant thickness, easy elevation with the help of power Doppler ultrasound information, and proper flap size for moderate defects caused by scar contracture release, superficial tumor ablation, and so on.     

One-stage reconstruction for defects of the mouth using a sternomastoid myocutaneous flap.

The sternomastoid muscle has 3 blood supplies: the occipital artery superiorly, the superior thyroid artery in the middle, and the thyrocervical trunk below. We report the use of a myocutaneous flap consisting of a "paddle" of skin on the end of a pedicle of sternomastoid muscle--with the latter based either on its superior or inferior blood supply. Fourteen such flaps have been used successfully in 13 consecutive patients for one-stage reconstructions of defects of the oral cavity and oropharynx. Although there was partial epithelial loss of the skin "paddle" in 7 cases, in each case the surviving dermis became resurfaced with epithelium.     

Breast Reconstruction with the free TRAM or DIEP flap: patient selection,choice of flap,and outcome

Recent reports of breast reconstruction with the deep inferior epigastric perforator (DIEP) flap indicate increased fat necrosis and venous congestion as compared with the free transverse rectus abdominis muscle (TRAM) flap. Although the benefits of the DIEP flap regarding the abdominal wall are well documented, its reconstructive advantage remains uncertain. The main objective of this study was to address selection criteria for the free TRAM and DIEP flaps on the basis of patient characteristics and vascular anatomy of the flap that might minimize flap morbidity. A total of 163 free TRAM or DIEP flap breast reconstructions were performed on 135 women between 1997 and 2000. Four levels of muscle sparing related to the rectus abdominis muscle were used. The free TRAM flap was performed on 118 women, of whom 93 were unilateral and 25 were bilateral, totaling 143 flaps. The DIEP flap procedure was performed on 17 women, of whom 14 were unilateral and three were bilateral, totaling 20 flaps. Morbidities related to the 143 free TRAM flaps included return to the operating room for 11 flaps (7.7 percent), total necrosis in five flaps (3.5 percent), mild fat necrosis in 14 flaps (9.8 percent), mild venous congestion in two flaps (1.4 percent), and lower abdominal bulge in eight women (6.8 percent). Partial flap necrosis did not occur. Morbidities related to the 20 DIEP flaps included return to the operating room for three flaps (15 percent), total necrosis in one flap (5 percent), and mild fat necrosis in two flaps (10 percent). Partial flap necrosis, venous congestion, and a lower abdominal bulge were not observed. Selection of the free TRAM or DIEP flap should be made on the basis of patient weight, quantity of abdominal fat, and breast volume requirement, and on the number, caliber, and location of the perforating vessels. Occurrence of venous congestion and total flap loss in the free TRAM and DIEP flaps appears to be independent of the patient age, weight, degree of muscle sparing, and tobacco use. The occurrence of fat necrosis is related to patient weight (p < 0.001) but not related to patient age or preservation of the rectus abdominis muscle. The ability to perform a sit-up is related to patient weight (p < 0.001) and patient age (p < 0.001) but not related to preservation of the muscle or intercostal nerves. The incidence of lower abdominal bulge is reduced after DIEP flap reconstruction (p < 0.001). The DIEP flap can be an excellent option for properly selected women.     

Clinical applications of the posterior rectus sheath-peritoneal free flap

Soft-tissue injuries involving the dorsum of the hand and foot continue to pose complex reconstructive challenges in terms of function and contour. Requirements for coverage include thin, vascularized tissue that supports skin grafts and at the same time provides a gliding surface for tendon excursion. This article reports the authors' clinical experience with the free posterior rectus sheath-peritoneal flap foil dorsal coverage in three patients. Two patients required dorsal hand coverage; one following acute trauma and another for delayed reconstruction 1 year after near hand replantation. A third patient required dorsal foot coverage for exposed tendons resulting from skin loss secondary to vasculitis. In all three patients, the flap was harvested through a paramedian incision at the lateral border of the anterior rectus sheath. After opening the anterior rectus sheath, the rectus muscle was elevated off of the posterior rectus sheath and peritoneum. When elevating the muscle, the attachments of the inferior epigastric vessels to the posterior rectus sheath and peritoneum were preserved while ligating any branches of these vessels to the muscle. Segmental intercostal innervation to the muscle was preserved. The deep inferior epigastric vessels were then dissected to their origin to maximize pedicle length and diameter. The maximum dimension of the flaps harvested for the selected cases was 16 X 8 cm. The anterior rectus sheath was closed primarily with non-absorbable suture. Mean follow-up was 1 year, and all flaps survived with excellent contour and good function in all three patients. Complications included a postoperative ileus in one patient, which resolved after 5 days with nasogastric tube decompression.     

Anterolateral thigh flap donor-site complications and morbidity

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.     

Differing flow patterns between ischemically challenged flap skin and flap skeletal muscle: implications for salvage regimens.

In this study, the authors tested the hypothesis that there is a significant difference in spatial patterns of reflow in skin as opposed to skeletal muscle after an ischemic insult. The authors believe that this pathophysiologic difference between the two flap types has significant implications for flap salvage strategies. Bilateral buttock skin flaps (10 x 18 cm) and latissimus dorsi myocutaneous flaps (10 x 20 cm) were elevated in Landrace pigs (n = 7). Flaps on one side of the animal were randomly assigned to 6 hours of arterial occlusion, with the contralateral side acting as control. At 15 minutes, 1 hour, and 4 hours after reflow, radioactive microspheres (15 microm) were injected into the left ventricle. After 18 hours of reperfusion, skin and muscle viability were estimated by intravenous fluorescein and soaking in nitroblue tetrazolium, respectively. Flow rates in the skin with an ischemia-reperfusion injury were significantly reduced (30 to 53 percent), at all time intervals, compared with controls. The flow rate in the fluorescent skin with ischemia-reperfusion injury of the latissimus dorsi flaps (0.037 ml/min/g at 15 min) was greater than in that of the buttock flaps (0.018 ml/min/g). The muscle flaps with ischemia-reperfusion injury had significantly higher flow rates than control muscle flaps at all time intervals studied (at 1 hour, 0.32 ml/min/g compared with 0.16 ml/min/g, respectively). In flap skeletal muscle, an early hyperemic phase during reperfusion maintains a significant blood flow to all regions, including the area of the flap that is destined for necrosis. In flap skin, however, there is a marked decrease in flow rates. These differences have important implications for the intravascular delivery of therapeutic agents to the damaged portions of the flap. Transdermal drug delivery systems should be explored as an alternative to intravascular regimens for the salvage of flap skin with ischemia-reperfusion injury.     

The distally pedicled peroneus brevis muscle flap: a new flap for the lower leg

Defects of the skin and soft tissue in the region of the lateral malleolus of the ankle and the Achilles tendon, resulting in exposed bone, tendons, or osteosynthetic material, cannot be covered with free skin transplants. Local or free flaps must be employed. The authors present the construction of a peroneus brevis muscle flap with a distal pedicle as a useful alternative. Between 1993 and 1999, distal pedicled peroneus brevis muscle flaps were used in 19 patients with various types of defects. During construction of the flap, both the long peroneal muscle and the peroneal artery remained intact. In the region of the distal third of the fibula, consistently arranged branches run from the artery into the muscle, and these form the distal pedicle. The proximal portion of the muscle can be transposed distally and easily extends to the tip of the fibula and the attachment of the Achilles tendon to the calcaneus. Primary healing occurred in 16 patients undergoing flap construction. Donor-site morbidity was mostly limited to the donor-site scar. The distally pedicled peroneus brevis muscle flap is a reliable means for covering defects in the lower leg. This form of muscle flap has not yet been described in the known literature. In the authors' opinion, this flap constitutes a logical and valuable extension of local flap procedures for plastic surgery in the distal leg region.     

Clinical salvage of three failing skin flaps by treatment with a vasodilator drug.

We present 3 clinical cases, one skin flap and two myocutaneous flaps, in which we believe postoperative treatment with isoxsuprine resulted in the salvage of considerable areas that would otherwise have necrosed.     

The trauma of suction-assisted lipectomy cannula on flap circulation in rats.

The effect of suction-assisted lipectomy on cutaneous blood vessels of inguinal skin flaps was studied and compared in 191 rats. Different types of cannula tips were used; the number of passes was standardized. In one experiment, following suctioning, 3 X 2 cm groin island flaps based on inferior epigastric pedicles were raised and then reattached. Fluorescein dye study and microangiography were performed to evaluate flap viability. Flap survival was determined clinically and by histologic examination on the fifth postoperative day. Three-sided inguinal random-pattern flaps were raised in a second experiment and reattached following suctioning. On the fifth postoperative day, surviving flap areas were measured using standard photographs and an imaging computer and were compared with controls. Results showed that cannula passes accompanied by vacuum are harmful to vessels, while those unaccompanied by vacuum are not. The greater the number of suctioning passes, the more trauma there is to vessels and the greater is the likelihood of flap necrosis. Conical and spatula tips were more harmful to vessels than spherical, cobra, keel cobra, or Fournier tips. These results support the conclusion that suction-assisted lipectomy enhances the possibility of skin necrosis by traumatizing the vascular pedicle of a flap, especially when it is used as an adjunct to flap elevation.     

Perforator topography of the deep inferior epigastric perforator flap in 100 cases of breast reconstruction

The anatomic topography of the perforators within the rectus muscle and the anterior fascia largely determines the time needed to harvest the perforator free flap and the difficulty of the procedure. In 100 consecutive cases, the topographic patterns of the perforators were investigated. In 65 percent, a short intramuscular course was seen. In 16 percent, a perforator at the tendinous intersection was encountered. In 9 percent, the largest perforator was found to have a long intramuscular course. In 5 percent, a subfascial course was found, and in another 5 percent, a paramedian course was found. In 74 percent of flaps, just one perforator was used, whereas two perforators were dissected in 20 percent. Only in 6 percent of flaps were three perforators used. A long intramuscular course (>4 cm) lengthens the dissection substantially, especially when the intramuscular course is in a step-wise pattern. The subfascial course requires precarious attention at the early stage of the perforator dissection when splitting the fascia. The perforators at the tendinous intersections are the most accessible and require a short but intense dissection in the fibrotic tissue of intersection. A paramedian perforator, medial to the rectus muscle, is a septocutaneous rather than a musculocutaneous perforator. The straightforward dissection almost extends up to the midline. Therefore, dissection always is performed at one side and, if no good perforators are present, continued at the intact contralateral side. The size of these perforators and their location in the flap determine the choice. One perforator with significant flow can perfuse the whole flap. If in doubt, two perforators can be harvested, especially if they show a linear anatomy so that muscle fibers can be split. The only interference with the muscle exists in splitting the muscle fibers. A perforator that lies in the middle of the flap is preferable. For a large flap, a perforator of the medial row provides better perfusion to zone 4 than one of the lateral row because of the extra choke vessel for the lateral row perforators. The clinical appearance of the perforators is the key element in the dissection of the perforator flap. Perforator topography determines the overall length and difficulty of the procedure.