Reducing the vascular delay period in latissimus dorsi muscle flaps for use in cardiomyoplasty

Although the mechanism by which vascular delay benefits skin flaps is not completely understood, this topic has been extensively studied and reported on in the literature. In contrast, little has been documented about the effects of vascular delay in skeletal muscle flaps. Recent animal studies tested the effectiveness of vascular delay to enhance latissimus dorsi muscle flap viability for use in cardiomyoplasty and found that it prevented distal flap necrosis. However, these studies did not define the optimal time period necessary to achieve this beneficial effect. The purpose of this study was to determine how many days of "delay" can elicit the beneficial effects of vascular delay on latissimus dorsi muscle flaps. To accomplish this, 90 latissimus dorsi muscles of 45 male Sprague-Dawley rats were randomly subjected to vascular delay on one side or a sham procedure on the other. After predetermined delay periods (0, 3, 7, 10, and 14 days) or a sham procedure, all latissimus dorsi muscles were elevated as single pedicled flaps based only on their thoracodorsal neurovascular pedicle. Latissimus dorsi muscle perfusion was measured using a Laser Doppler Perfusion Imager just before and immediately after flap elevation. The muscles were then returned to their original vascular beds, isolated from adjacent tissue with Silastic film, sutured into place to maintain their original size and shape, and left there for 5 days. After 5 days, the latissimus dorsi muscle flaps were dissected free, scanned again (Laser Doppler Perfusion Imager-perfusion measurements), and the area of distal necrosis was measured using digitized planimetry of magnified images. The authors' results showed that delay periods of 3, 7, 10, and 14 days significantly increased (p < 0.05) blood perfusion and decreased (p < 0.05) distal flap necrosis when compared with sham controls. On the basis of these findings, the authors conclude that in their rat latissimus dorsi muscle flap model the beneficial effects of vascular delay are present as early as 3 days. If these findings also hold true in humans, they could be useful in cardiomyoplasty by allowing surgeons to shorten the amount of time between the vascular delay procedure and the cardiomyoplasty procedure in these very sick patients.     

Improved perfusion after subcritical ischemia in muscle flaps treated with vascular endothelial growth factor

Vascular endothelial growth factor (VEGF), a potent endothelial mitogen, is secreted in ischemic tissue and plays a pivotal role in angiogenesis. We studied whether VEGF administered to a rat muscle flap at the time of ischemia induction would increase microcirculatory flow to the flap. The cremaster muscle flap was isolated on its neurovascular pedicle. Ischemia was induced by clamping the vascular pedicle, and 0.2 ml of either VEGF (0.1 microg) or vehicle (phosphate-buffered saline) was immediately infused into the muscle. After 4 or 6 hours, the clamps were released, and the cremaster was placed in a pocket in the medial thigh for 24 hours. The muscle was then dissected, and microcirculatory measurements were made under intravital microscopy. Six animals were used in each of the four groups. All flaps exposed to 6 hours of ischemia, the duration considered to be critical ischemia, had no significant microcirculatory flow, regardless of treatment with VEGF. In the 4-hour ischemia group, or subcritical ischemia group, red blood cell velocity in arterioles was 14 mm/sec in muscles treated with VEGF and 9 mm/sec in controls (p = 0.02), and capillary flow was 7 per high-power field in muscles treated with VEGF versus 2 per high-power field in controls (p = 0.0005). Thus, VEGF did not alter microcirculatory flow in a muscle flap exposed to critical ischemia, but it did enhance flow to a flap exposed to subcritical ischemia.     

Effect of vascular delay on viability, vasculature, and perfusion of muscle flaps in the rabbit

The delay procedure is known to augment pedicled skin or muscle flap survival. In this study, we set out to investigate the effectiveness of vascular delay in two rabbit muscle flap models. In each of the muscle flap models, a delay procedure was carried out on one side of each rabbit (n = 20), and the contralateral muscle was the control. In the latissimus dorsi flap model, two perforators of the posterior intercostal vessels were ligated. In the biceps femoris flap model, a dominant vascular pedicle from the popliteal artery was ligated. After the 7-day delay period, the bilateral latissimus dorsi flaps (based on the thoracodorsal vessels) and the bilateral biceps femoris flaps (based on the sciatic vessels) were elevated. Animals were divided into three groups: part A, assessment of muscle flap viability at 7 days using the tetrazolium dye staining technique (n = 7); part B, assessment of vascular anatomy using lead oxide injection technique (n = 7); and part C, assessment of total and regional capillary blood flow using the radioactive microsphere technique (n = 6). The results in part A show that the average viable area of the latissimus dorsi flap was 96 +/- 0.4 percent (mean +/- SEM) in the delayed group and 84 +/- 0.7 percent (mean +/- SEM) in the control group (p < 0.05, n = 7), and the mean viable area of the biceps femoris flap was 95 +/- 2 percent in the delayed group and 78 +/- 5 percent in the control group (p < 0.05, n = 7). In part B, it was found that the line of necrosis in the latissimus dorsi flap usually appeared at the junction between the second and third vascular territory in the flap. Necrosis of the biceps femoris flap usually occurred in the third territory, and occasionally in both the second and the third territories. In Part C, total capillary blood flow in delayed flaps (both the latissimus dorsi and biceps femoris) was significantly higher than that in the control flaps (p < 0.05). Increased regional capillary blood flow was found in the middle and distal regions, compared with the control (p < 0.05, n = 6). In conclusion, ligation of either the dominant vascular pedicle in the biceps femoris muscle flap or the nondominant pedicle in the latissimus dorsi muscle flap in a delay procedure 1 week before flap elevation improves capillary blood flow and muscle viability. Vascular delay prevents distal flap necrosis in two rabbit muscle flap models.     

Prophylactic co-trimoxazole in biliary surgery.

A double-blind study was conducted to test the prophylactic effect of a single dose of co-trimoxazole on the incidence of septic complications after elective cholecystectomy. Forty-eight patients received co-trimoxazole and 47 placebo. Wound sepsis occurred in 10 (21%) of the controls but in only 2 (4%) of the treated group, and the incidences of pulmonary complications were 49% (23 cases) and 19% (9) respectively. These differences were significnat. Wound sepsis after cholecystectomy occurs mostly in patients with infected bile. Co-trimoxazole given by intravenous infusion rapidly achieves a high concentration in the palsma and is effective against most biliary pathogens.     

Gene therapy by adenovirus-mediated vascular endothelial growth factor and angiopoietin-1 promotes perfusion of muscle flaps

An experimental study was conducted to investigate the potential use of intravascular gene therapy with adenovirus-mediated (Ad) vascular endothelial growth factor (VEGF) or angiopoietin-1 (Ang-1) for the enhancement of muscle flap perfusion and to evaluate the effect of therapy on microcirculatory hemodynamics and microvascular permeability in vivo by using a cremaster muscle flap model in the rat. The cremaster tube flap was left intact after isolation of the pudo-epigastric pedicle. A total of 90 male Sprague-Dawley rats were divided into five groups of 18 each, according to the type of intraarterial treatment. Control flaps received phosphate-buffered saline. Group 2 (the control gene encoding green fluorescent protein, Ad-GFP) served as the adenovirus control. In Groups 3, 4, and 5, flaps were pretreated with Ad-VEGF, Ad-Ang-1, and Ad-Ang-1 + Ad-VEGF, respectively. Flaps were preserved in a subcutaneous pocket in the hindlimb for evaluation of functional capillary density and microvascular permeability indices at 3, 7, and 14 days by intravital microscopy system. At day 7 and 14, Ad-VEGF, Ad-Ang-1, and combined treatment groups showed significantly higher numbers of capillary densities when compared with control and Ad-GFP groups (p < 0.05). At day 14, Ad-VEGF was the superior treatment group compared with Ad-Ang-1 and Ad-VEGF + Ad-Ang-1 (p < 0.05). Overall, there was a linear increase in the number of functional capillaries in all treatment groups (p < 0.05). At day 3 after Ad-Ang-1 therapy, a significantly lower permeability index was found when compared with Ad-VEGF + Ad-Ang-1 and Ad-VEGF alone treatment (p < 0.05). At day 7, the Ad-VEGF group had the highest score of permeability index compared with control, combined, and Ad-Ang-1 groups (p < 0.05). Histologic evaluation of muscle flaps demonstrated mild focal inflammation. There was evidence of mild vasculitis in all flaps except control muscles. Intravascular angiogenic therapy with Ad-VEGF or Ad-Ang-1 was technically feasible, as demonstrated by expression of the control gene, GFP, along the vascular tree. All treatment groups increased perfusion of the muscle flap over a period of 14 days, indicating a long-lasting effect of gene therapy. Ang-1 alone or in combination with VEGF was as effective as VEGF alone in augmenting muscle perfusion with more stable vessels 1 week after gene therapy.     

The role of muscle flaps in pulmonary aspergillosis

Pulmonary invades the lung parenchyma and vessels, causing necrotizing pneumonia and massive hemoptysis in immunocompromised patients. Medical treatment alone often fails to clear the organism. Early surgical intervention is advocated in localized disease to remove infection near pulmonary vessels. The resection is limited in an attempt to preserve as much lung function as possible. However, preexisting cavitations and lung disease predispose to postoperative space problems, including prolonged air leak, bronchopleural fistula, and empyema. Muscle flaps provide a solution to these problems by obliterating residual space and providing protective coverage to the bronchial stump. The authors present four cases of pulmonary aspergillosis treated by multimodality therapy and extrathoracic muscle flap transposition. Factors that may contribute to successful treatment include underlying condition of the host and history of cancer, radiation therapy, and great vessel involvement. Despite aggressive medical and surgical therapy, pulmonary aspergillosis has a poor prognosis.     

Prophylactic antibiotics in plastic and reconstructive surgery.

There is no consensus in the literature on the use of prophylactic antibiotics to prevent postoperative infection. This study was performed to investigate whether the use of prophylactic antibiotics has an effect on postoperative infection rates. A total of 1400 patients were classified into four groups based on their diagnosis. During the induction of anesthesia, half of each group received 2 g of a sulbactam-ampicillin combination and the other half received a placebo (saline solution) intravenously. Wound infection rates were observed in the postoperative period. Age, sex, and operative site of the patients with the same diagnosis were comparable in each group. The white blood cell count and the body temperature reading of each patient were recorded postoperatively. Wounds were observed daily in the postoperative period and graded according to a predetermined scale. Bacteriologic specimens were obtained from patients who had wound infections. According to our clinical experience, antibiotic prophylaxis is not necessary in plastic surgery. At the end of our 6-year study, a significant difference could not be found between the antibiotic prophylaxis and placebo groups.     

Intrathoracic muscle flaps: a 10-year experience in the management of life-threatening infections

From 1977 to 1987, 87 consecutive patients underwent intrathoracic muscle transposition. Indications for the operation were bronchopleural fistula, postpneumonectomy empyema, perforation of the heart or great vessels, esophageal fistula, tracheal fistula, empyema, and prophylactic reinforcements of the airway. Of the 118 muscles transposed, the serratus anterior was used in 48 patients, the latissimus dorsi in 33, the pectoralis major in 26, and other muscles in 11. Depending on the wound status at the time of muscle transposition, the chest either was left open for dressing changes or was closed primarily. The number of operations per patient ranged from 1 to 16 (median 2). There were 13 operative deaths (14.9 percent). The follow-up period ranged from 3.9 to 130.9 months (median 28.3 months). Overall results were excellent in 65 patients (74.7 percent). There was no difference in results when considered according to treatment indication. We conclude that when there is an actual or potential leak of the tracheobronchial tree, heart and great vessels, or intrathoracic gastrointestinal tract, intrathoracic muscle transposition can be a lifesaving adjunct.     

Regional intravascular sympathetic blockade for better results in flap surgery: an experimental study of free flaps, island flaps, and pedicle flaps in the rabbit ear

Flap survival is still a major problem in reconstructive surgery. Increased flap survival after systemic administration of drugs inhibiting the adrenergic system has been reported in experimental studies. The clinical use, however, is restricted by systemic side effects. It has been demonstrated that, using guanethidine, an effective regional intravascular sympathetic (RIS) block can be obtained without systemic effects. Using this type of block, an experimental study was made on the survival and quality of different types of flaps in the rabbit ear. The results obtained in 72 flaps created in the ears of 36 rabbits were assessed by the extent of flap edema, peripheral neovascularization, flap temperature, and flap surviving area. The RIS block reduced edema and scab formation, caused higher flap temperatures, better neovascularization, and increased surviving flap area, as compared with equal flaps in the untreated contralateral ear of the same animal. The effect of RIS block may be considered as a "pharmacological delay" procedure. From the experiments as well as clinical experience, it may be concluded that this technique is a safe and effective procedure. Therefore, the RIS block method is recommended for clinical use in flap techniques in extremities of man.     

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.     

Treatment of late ulceration in free muscle flaps to the foot

One of the preferred methods for the repair of large defects of the foot has been the use of free muscle flaps covered with skin grafts. Although this method has served well, some patients will experience ulceration in the weight-bearing surface. Three cases are reported in which small ulcerations developed in the heel after reconstruction of traumatic defects with muscle free flaps. All three patients were treated with a neurovascular island flap from the side of the great toe. All three patients are active young males, and all three patients have subsequently maintained intact skin for an average of 6.8 years (range, 5.1 to 9.1 years).     

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.