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.     

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.     

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.     

Vastus medialis myocutaneous and myocutaneous-tendinous composite flaps

This report describes a new myocutaneous territory and introduces a new myocutaneous flap based on the vastus medialis muscle. Dissection, arterial dye perfusion, and specimen angiography of 32 fresh cadaver legs defined a vastus medialis myocutaneous territory directly overlying the muscle and also defined a segment of quadriceps femoris tendon vascularized by the muscle. This vascular unit provides a myocutaneous flap for closure of anterior knee defects. This flap can also be designed as a composite myocutaneous-tendinous flap by inclusion of the vascularized quadriceps femoris tendon segment, which allows reconstruction of missing patellar tendon segments. The distal advancement flap design with retention of motor innervation preserves vastus medialis contribution to knee extension. Clinical applications of vastus medialis myocutaneous and myocutaneous-tendinous flaps are illustrated by their use in three patients with knee defects and patellar tendon losses. The potential value of vascularized tendon (versus vascular free tendon grafts) for patellar tendon reconstruction is discussed.     

Primary and secondary critical ischemia times of myocutaneous flaps

The primary critical ischemia time of the latissimus dorsi myocutaneous flap model was determined in the pig. Latissimus dorsi flaps were subjected to a primary ischemic insult of 2 hours (mimicking the ischemic event of free-tissue transfer). Following 12 hours of normal flow, the flaps were subjected to a second ischemic insult ranging from 0 to 12 hours. The secondary critical ischemia time (11.3 hours) was found to be statistically comparable to the primary critical ischemia time (9.1 hours). Questions are raised concerning the mechanism of action of this phenomenon and its clinical relevance.     

Latissimus dorsi myocutaneous flaps in head and neck reconstruction.

We have found the latissimus dorsi myocutaneous flap, when used as a "pedicled island flap," to be an adaptable and dependable alternative flap for repairs after major resections in the head and neck. The long vascular pedicle, containing large vessels, provides a means to transfer a large bulk of tissue into the head and neck for the repair of major through-and-through defects.     

Successful use of muscle flaps or myocutaneous flaps in patients with sickle cell disease.

Sickle cell disease presents an unusual challenge to the reconstructive surgeon. The interaction between the underlying hemoglobinopathy and the circulatory mechanics in pedicled flaps leads to a high incidence of flap necrosis in patients with this disease. We present 3 patients with sickle cell disease in whom the use of axial flaps allowed the repair of difficult reconstructive problems in one stage, without preoperative exchange transfusions. The rationale for this approach is discussed.     

Sensibility and cutaneous reinnervation in free flaps

Sensibility and sensory reinnervation were investigated in 19 free flaps, predominantly located on the lower extremities, between 2 months and 3 years after flap transfer. All patients showed deep pressure sensibility. In 10 of the patients, primarily those examined late after surgery, a heat pain threshold was obtained at about 50 degrees C. None of the patients had superficial sensibility of any other modality. No neurofilament-positive sensory nerve fibers were observed in the dermis or epidermis. In one patient nerve fibers were detected in the subcutaneous tissue. It is concluded that patients will have deep pressure sensibility of the flap area even early after the operation and that most patients will develop a heat pain sensitivity, probably due to subcutaneous reinnervation.     

The pig as an experimental animal in plastic surgery research for the study of skin flaps, myocutaneous flaps and fasciocutaneous flaps

The pig serves as an excellent model of skin flap research. Many flap types are available and flap designs can be modified easily for specific experimental requirements. Swine are large enough to permit multiple flaps and the skin color allows subjective observations of tissue circulation.     

Experience with thirteen latissimus dorsi myocutaneous free flaps.

Subcutaneous "pocketing" is proposed as a simple and convenient method to nourish a denuded, replanted end of a finger, when the amputation is between the lunule and the DIP joint. The investigation of a laboratory model is presented, and our initial clinical experience is reported.     

Gluteus maximus myocutaneous flaps for repair of pressure sores.

Myocutaneous flaps based on the gluteus maximus muscle, and its blood supply, have many advantages for the surgical repair of pressure sores in paraplegics. These are described, as well as the techniques used in various areas.     

Reconstruction of the nasal tip using nasalis myocutaneous sliding flaps

An alar island subcutaneous sliding flap is described which, when analyzed, is actually myocutaneous, based on the lower portions of the nasalis muscle. In a series of 47 patients, tip defects 1.25 cm in diameter were reconstructed with a unilateral flap, and defects 2.0 cm in diameter were reconstructed with a bilateral flap. The advantage of the flap lies in aesthetics, which are so important in tip surgery. Not only are the incisions at or parallel with the edges of the lateral crus of the lower lateral cartilage, but also chronic edema and "dog-ears" so common after rotation pedicle flaps are avoided.     

Vaginal and pelvic reconstruction with distally based rectus abdominis myocutaneous flaps

This report introduces a new method of vaginal reconstruction using a single rectus abdominis myocutaneous flap based distally. Applications of this flap in reconstruction of major abdominal wall and pelvic defects, such as hemipelvectomies, are also described. The flap is designed to carry a paddle of upper abdominal skin on a distally based muscle and vascular pedicle. Advantages of this flap design are (1) the technique is straightforward and rapid, (2) flap viability is reliable, (3) the epigastric skin-fascial donor defect preserves the anterior rectus fascia distal to the linea semicircularis, which prevents hernia, (4) a large arc of rotation is provided, and (5) the epigastric donor site does not interfere with colostomy and urinary conduit stomas in the pelvic exenteration patient. We have done 11 vaginal reconstructions and 9 major pelvic defect reconstructions with this flap during the last 3 1/2 years. In these 20 patients, the only complications were two partial flap losses. No major flap losses or ventral hernias occurred.     

Uses of the trapezius and sternomastoid myocutaneous flaps in head and neck reconstruction.

Both of these myocutaneous flaps can supplant forehead and deltopectoral flaps, in certain indications. They are additional arterialized flaps for the armamentarium of the reconstructive surgeon, and can be useful in many repairs in the head and neck region.