Perforator-based flaps for low posterior midline defects

A new type of flap is described based on unnamed perforators located near the midline of the lower back region. Such flaps combine the superior blood supply of the myocutaneous flap with the lack of donor-site morbidity of a skin flap. Five clinical cases are presented, showing how such perforators can augment skin flaps or create custom-designed island flaps. The dissection of the flap is described, and further possibilities for its use are suggested.     

Use of thirty latissimus dorsi flaps

Experiences with 30 latissimus dorsi flaps are described. Used either as a muscle flap, as a myocutaneous flap, or as an "island" of skin nourished by a subcutaneous pedicle of muscle and vessels, the flap has an excellent blood supply and is suitable for many repairs of defects of the chest wall.     

Repair of a huge defect of the gluteal region by rotation of a combined tensor fasciae latae-sartorius myocutaneous flap

Although the tensor fasciae latae myocutaneous flap is convenient for covering some defects in the gluteal region, it is not suitable to repair a huge defect because of its limited area. Based on the close relationship of the sartorius and the tensor fasciae latae at their origins and blood supply, the authors designed a myocutaneous flap containing both the tensor fasciae latae and the sartorius muscles and their skin territories with an area exceeding 800 cm2. Two successfully repaired patients are reported. The flaps provide normal sensitivity. The vascular pedicle has a reliable anatomy, being easily dissected, and averages 4.6 to 5.8 cm in length. Both muscles are expendable. There is little functional difficulty for hip joint after the operation.     

Effects of sodium pentobarbital anesthesia on blood flow in skin, myocutaneous, and fasciocutaneous flaps in swine.

Drug effect on flap blood flow is most commonly determined in anesthetized animals, yet the effect of the anesthetic is often poorly understood. Halothane and nitrous oxide cause profound changes in skin blood flow and thus provide an unsuitable anesthetic technique for use in measuring drug effects on skin and myocutaneous flaps in swine. The goal of this study was to determine the effects of sodium pentobarbital anesthesia on cardiovascular parameters and blood flow in skin, myocutaneous, and fasciocutaneous flaps in pigs. In seven pigs, 7 forelimb skin flaps, 7 forelimb fasciocutaneous flaps, 14 arterial buttock flaps, and 14 latissimus dorsi flaps were created. Blood flow was measured at 2-cm intervals along each flap while the animal was awake and anesthetized. A cardiac depressant effect of pentobarbital was observed, but no change in blood flow could be demonstrated in control skin or control muscle. However, pentobarbital did significantly increase blood flow in all viable portions of arterial and random skin flaps, fasciocutaneous flaps, and the cutaneous segments of the latissimus dorsi flap. These demonstrated effects of pentobarbital should be taken into consideration in designing and analyzing studies of flap blood flow in the acute postoperative phase.     

The effects of the nitric oxide donor SIN-1 on ischemia-reperfused cutaneous and myocutaneous flaps

Ischemia-reperfusion injury causes tissue damage that leads to a decrease in bioavailability of nitric oxide. The authors hypothesized that an exogenous supply of nitric oxide will have beneficial effects on survival of skin and skeletal muscle subjected to ischemia-reperfusion injury. By using the nitric oxide donor SIN-1 (3-morpholino-sydnonimine) the effects of direct intraarterial infusion of an exogenous source of nitric oxide in reperfused flaps was studied. Bilateral island buttock skin flaps and latissimus dorsi myocutaneous flaps were elevated in eight pigs, for a total of 32 flaps. Flaps were subjected to 6 hours of ischemia followed by 18 hours of reperfusion. Flaps on one side of each animal were randomized to be treated with the nitric oxide donor (treatment group). The contralateral side was treated with an equivalent volume of saline vehicle (infusion control) SIN-1, or saline was administered as a continuous direct intraarterial infusion at the onset of reperfusion and continued during the observation period. Outcomes measured were tissue neutrophil accumulation by using myeloperoxidase assay and tissue survival (intravenous fluorescein and nitroblue tetrazolium for skin and muscle, respectively). In both skin and myocutaneous flaps, SIN-1 treatment caused a significant improvement in survival and a decrease in neutrophil accumulation. Nitric oxide may play an important role in the pathophysiologic process of ischemia-induced reperfusion injury in skin and skeletal muscle. Nitric oxide donors may be a promising family of therapeutic agents for the prevention of ischemia-induced reperfusion injury in cutaneous and myocutaneous flaps.     

Critical ischemia times and survival patterns of experimental pig flaps

Previous work on critical ischemia time suggested (1) a greater susceptibility of myocutaneous flaps over skin flaps to the ischemia reperfusion injury and (2) that duration of ischemia may affect the survival area of a flap. Using a pig model, 55 animals were operated on and the critical ischemia times and survival patterns of the buttock skin (n = 85) and latissimus dorsi myocutaneous (n = 88) island flaps were determined after being submitted to 0, 2, 4, 6, 8, 10, 12, 14, and 16 hours of normothermic ischemia. The average critical ischemia times (CIT50) were determined to be 9 and 10 hours for the buttock skin and latissimus dorsi myocutaneous flaps, respectively. Percentage of total area surviving (%TAS) in those flaps which did survive was adversely affected by increases in the ischemic interval in both flap models. A statistically significant decrease in percentage of total area surviving was found after 6 and 8 hours of ischemia for the buttock skin and latissimus dorsi myocutaneous flaps, respectively.     

Breast reconstruction with contralateral rectus abdominis myocutaneous flap

A transverse myocutaneous rectus abdominis flap from the contralateral side has been employed for breast reconstruction in 52 patients. This flap has the advantage of balancing the patient by utilizing skin from an area of relative excess. The blood supply to the flap is based on the superior epigastric vessel and its perforators. The scar of the donor area is acceptable because it falls in the submammary sulcus. The use of a silicone implant can be avoided in some patients because of the adequate bulk of skin, muscle, and fat that is available. Abdominoplasty of the superior abdomen can be obtained during the same operation and can enhance the overall aesthetic results. Breast reconstruction is now possible with either ipsilateral or contralateral upper-abdominal transfer flaps, and further refinement of operative technique using the contralateral upper-rectus abdominis myocutaneous island flap must await further experience.     

The differing effects of isoxsuprine on muscle flap and skin flap survival in the pig

The pretreatment of pigs with isoxsuprine for two weeks resulted in a significant increase in the surviving length of sartorius muscle flaps when compared with untreated flaps on the same animal. However, there was no improvement in the surviving length of neurovascular island skin flaps when these animals were treated with isoxsuprine. The difference in these results is thought to be due to the action of isoxsuprine on the blood supply of skeletal muscle.     

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.     

Anatomic basis of plantar flap design

Safe planes exist for plantar incisions that minimize the possibility of subcutaneous nerve injury and are therefore useful in flap design. Nerve branch orientation in the plantar subcutaneous tissue is specific and guides dissection so as to avoid producing anesthesia in weight-bearing areas. An extensive proximal plantar subcutaneous plexus exists that permits elevation of plantar flaps in a superficial plane. This is due to the major contribution that the dorsal circulation makes to the skin of the plantar surface. The blood supply to the non-weight-bearing midsole area is not from the medial plantar artery exclusively. This is a watershed area with important lateral plantar artery and dorsalis pedis artery contributions as well. It is not necessary or desirable to base plantar flaps on a myocutaneous or fasciocutaneous supply with its required deep dissection. Local plantar flaps can be designed to include sensation and abundant blood supply without the need for "subfascial" dissection. Subcutaneous sensory plantar flaps designed in accordance with these principles promise a more ideal solution for the treatment of plantar defects.     

Clinical definition of independent myocutaneous vascular territories.

The use of myocutandous flaps can increase the possibilities for construction in many cases by bringing in new blood supply to avascular areas by furnishing additional bulk for filling defects or covering bone grafts or other deep repairs, and sometimes by making longer flaps viable. Also, the need for delay procedures is decreased and sometimes avoided. In this paper we define the vascular territories of 13 clinical myocutaneous flaps, and we describe possible uses of them. Three illustrative clinical cases are presented, in which repairs were done with these flaps. The future uses of these flaps challenge the imagination. Knowledge about them may significantly alter the traditional approaches to flap designs and repairs.     

Repair of ischial pressure ulcers with gracilis myocutaneous island flaps.

Ischial pressure sores can be repaired with gracilis myocutaneous island flaps, and this technique offers numerous advantages over the use of posterior thigh flaps. Several illustrative cases are described.     

Use of an adipofascial flap based on the proximal perforators of the ulnar artery to correct contracture of elbow burn scars: an anatomic and clinical approach.

Different techniques can be used to repair contracture of burn scars on the elbow, including local or distant pedicle flaps, muscle or myocutaneous flaps, free flaps, and tissue expanders. Among these, a pedicled adipofascial flap based on the most proximal two to four perforators of the ulnar artery (located 1 to 5 cm from the origin of the artery) can be anastomosed to form a sort of axially patterned blood supply within the fascia and subcutaneous fat. Therefore, no major vessel in the forearm need ever be severed. In addition, use of this type of flap preserves muscle function. The pedicled adipofascial flap described in this article allows for early rehabilitation because the flap is thin and pliable. Additional advantages are the easy and quick dissection and completion of the procedure in one stage. A detailed anatomic dissection of the flap was performed on 16 upper extremities from fresh cadavers; an injection study was also performed to determine the location and dimensions of the pedicle flap and its area of reach around the elbow. In the past 3 years, 14 flaps were used in 13 patients to repair elbow defects after release of burn scar contractures. Flap dimensions ranged from 4 x 7 cm to 6 x 14 cm (mean flap size, 74 cm). The results were very satisfactory.     

Differential effects of venous stasis and arterial insufficiency on tissue oxygenation in myocutaneous island flaps: an experimental study in pigs.

The supply, consumption, and tissue tension of oxygen were studied in experimental bilateral myocutaneous island flaps in five control pigs and in eight pigs during progressive 1-hour intervals of flap ischemia. Progressive ischemia was obtained by partial to complete clamping of the artery in one flap, producing arterial insufficiency, and simultaneous clamping of the vein in the other flap, producing venous stasis. Blood flow was reduced to 50, 25, and 0 percent of baseline. In the arterial insufficiency flaps, the oxygen tension in subcutaneous tissue, muscle, and venous outflow was significantly reduced once blood flow was reduced to 50 percent of baseline. Oxygen consumption during partial vessel occlusion was lower in the venous stasis flaps than in the arterial insufficiency flaps when blood flow was reduced to 25 percent of baseline, suggesting either that cellular metabolism is reduced in the venous stasis flaps or that the oxygen which is delivered is unavailable for the cells. Increased presence of tissue fluid in the venous stasis flap inhibits the diffusion of oxygen through the interstitial tissue, and this may explain the lower oxygen consumption. During 3 hours of reperfusion, increased blood flow was observed in the arterial insufficiency flaps, whereas blood flow in the venous stasis flaps was sluggish. The arterial insufficiency flaps recovered more rapidly than the venous stasis flaps during the first hour of reperfusion, judged by the rate of increase in oxygen tension and the higher venous oxygen tension. Oxygen tension increased more rapidly in muscle than in subcutaneous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

The dorsal scapular island flap: an alternative for head,neck, and chest reconstruction

The back has become an increasingly popular donor site for flaps because it can provide thin, pliable tissue, with minimal bulk, and the scar can be easily hidden under clothing. The authors performed a cadaveric and clinical study to evaluate the anatomy of the dorsal scapular vessels and their vascular contribution to the skin, fascia, and muscles of the back. On the basis of anatomical studies in 28 cadavers and clinical experience with 32 cases, it was concluded that the dorsal scapular vessels provide a reliable blood supply to the skin of the medial back, making it a versatile flap to use as an island flap. A flap raised on the dorsal scapular vessels can be harvested with a long pedicle and can be rotated to reach as far as the anterior regions of the head, neck, and chest wall. Delaying and expanding the flap may help to facilitate venous drainage. The authors recommend the use of this versatile island pedicle flap as an alternative to microvascular free-tissue transfer for the reconstruction of defects in the head, neck, and anterior chest.     

Extended lower trapezius island myocutaneous flap: a fasciomyocutaneous flap based on the dorsal scapular artery

The lower trapezius island myocutaneous flap is a useful flap in head and neck reconstruction. It is thin and pliable and can reach defects in most areas of the head and neck. Its usefulness in head and neck reconstruction has often been limited or discouraged by reports of significant failure rates. In this study, the vascular anatomy and clinical use of the extended lower trapezius myocutaneous flap based solely on the dorsal scapular artery system are elucidated, and experience gained performing 20 flaps over the past 5 years by using the extended lower trapezius myocutaneous flap is reported. The vascular anatomy of the dorsal scapular artery system is reviewed in 13 fresh cadaveric dissections by using methylene blue, latex injection studies, and radiologic examination.     

Salvage of seeing eyes after avulsion of upper and lower lids

It is often stated that any injury severe enough to avulse both lids will inevitably destroy the globe. Two cases are presented in which the globe was uninjured but exposed, requiring immediate coverage. Local skin flaps placed over mobilized conjunctiva were used for emergency cover. One was eventually made into functioning eyelids; the other remains dormant. First-line options for local flaps may not be available because of regional trauma. The reconstructive surgeon caring for acute trauma patients should be familiar with all available options, including recently described island and myocutaneous flaps.     

A new experimental model for myocutaneous flaps: latissimus dorsi of the rabbit--an anatomic study

A new experimental model, the latissimus dorsi flap of the rabbit, was studied. This was found to be a relatively inexpensive research model. Its use is advocated for composite tissue transfer as transposition, island, or free myocutaneous flaps.     

Peripheral neovascularization of muscle and musculocutaneous flaps in the pig.

Late loss of free muscle flaps following surgical or accidental trauma to the dominant vascular pedicle has been reported. In this study, time-dependent ligation of the dominant vascular pedicle was undertaken in denervated latissimus dorsi musculocutaneous or muscle-only island flaps in the pig. Muscle flaps were covered with a skin graft, and silicon rubber sheets were inserted between the flaps and their bases to simulate a poorly vascularized bed. Hemodynamic and viability studies were then performed using intravenous fluorescein (skin viability), tetrazolium blue (muscle viability), and radiolabeled 15-micron microspheres (capillary blood flow). Blood flow did not change in acutely raised musculocutaneous flaps (n = 10) but was significantly elevated in acutely raised muscle-only flaps (n = 10), suggesting that the skin paddle may steal blood flow from the underlying muscle in musculocutaneous flaps. Peripheral neovascularization at 1 day to 8 weeks was assessed (n = 30). Viability increased during the first week of revascularization and was not different in musculocutaneous and muscle-only flaps. Revascularization of muscle-only flaps was enhanced compared with musculocutaneous flaps in the 2- to 8-week period.     

Effect of glucocorticoid treatment on skin capillary blood flow and viability in cutaneous and myocutaneous flaps in the pig

The effect of methylprednisolone treatment on skin-flap viability and capillary blood flow was studied in a series of four experiments. Intramuscular methylprednisolone injections (30 mg/kg per day), given in single or divided doses preoperatively or postoperatively, had no effect in augmenting skin viability in arterialized cutaneous, myocutaneous, or random skin flaps compared with the control. Capillary blood flow was studied in arterial buttock flaps and latissimus dorsi myocutaneous flaps raised on animals treated preoperatively with methylprednisolone or saline (control), and no significant difference in capillary blood flow was noted between the treatment and control flaps. It was concluded that methylprednisolone has no significant therapeutic effect either in increasing flap viability or in increasing capillary blood flow in skin flaps in pigs.