Survival Of Experimental Skin Flaps Research Articles

Local pharmacological preconditioning increases the survival of experimental skin flaps in rats

Skin flap survival is dependent on an adequate blood supply and on the resistance to ischemia. Experimentally we tested the effect of pharmacological preconditioning on the survival of skin flaps. The survival of an ischemic skin flap (McFarlane flap) was tested using the local application of cobalt gel in three groups of Wistar rats. The mean flap necrosis of the control group was 59.15%. The rats treated by the cobalt gel once a week showed mean necrosis in 39.09%; the rats receiving the application of the cobalt gel three times a week in 26.33%. The treated groups presented with significantly lower flap necrosis in comparison to the untreated controls. There was a significant difference in the flap necrosis occurrence according to the application frequency of the cobalt gel. The expression of the genes involved in angiogenetic processes encoding vascular endothelial growth factor (VEGF) and glycolytic enzymes was influenced in a non-mitochondrial way in this study. The results show that non-mitochondrial preconditioning could prolong the survival of an ischemic flap.

Evaluation of a continuous systemic infusion of iloprost, a stable PGI-2 analog, on the survival of experimental skin flaps.

Numerous investigators have attempted to enhance the survival of ischemic experimental skin flaps using various pharmacologic manipulations. Recently, the authors' laboratory demonstrated the beneficial effect of iloprost, a stable PGI2 analogue, as a post-ischemic perfusion washout, in improving the survival of ischemic skin flaps. The rat unilateral abdominal skin flap, based on the superficial epigastric vessels, was utilized in this study involving 30 animals. The animals were divided into three different treatment groups, with ischemic periods of 16 and 18 hr. Perfusion washouts were performed at the completion of the various ischemic periods. Alzet osmotic pumps were used to deliver a continuous systemic infusion of iloprost for 7 days postoperatively. The groups consisted of the following: Group 1 (single ILO)--perfusion washout with iloprost only; Group 2 (continuous LD ILO)--low-dose systemic iloprost infusion (0.066 mcg/kg/min) and perfusion washout with iloprost; and Group 3 (continuous HD ILO)--high-dose systemic iloprost infusion (0.1 mcg/kg/min) and perfusion washout with iloprost. The percentage of flap survival was assessed on postoperative day 7. Skin flaps of the animals receiving the continuous systemic infusion of iloprost were noted to have varying percentages of survival, while skin flaps undergoing perfusion washout only were found to have either complete survival using a continuous systemic infusion of iloprost, compared to iloprost perfusion washout alone. In addition, the hypotensive side effects of systemic iloprost infusion limit its use in the rat skin-flap model.

A study of topical and systemic Prostaglandin E1 and survival of experimental skin flaps

A study has been undertaken to investigate Prostaglandin E1 administration procedure for improving flap survival. Whether the drug was administered continuously or transcutaneously using a silicone gel drug delivery system; or was topically injected into the critical zone of the flap; or was intraperitoneally administered intermittently over an hour after surgery a statistically significant improvement of flap survival occurred (P < 0.01, Student's t-test). However, no improvement of flap survival was seen when the drug was administered only once intraperitoneally immediately after flap elevation, although administered doses of the drug in those rats was equal to the doses in the rats which received intermittent administration of the drug intraperitoneally over an hour after surgery.

Disease Cuono, C. B. et al. Augmentation of experimental skin flap survival via postoperative phosphocreatine replacement

Disease Cuono, C. B. et al. Augmentation of experimental skin flap survival via postoperative phosphocreatine replacement

Effects of pentoxifylline on experimental skin flap survival.

We studied the effects of pentoxifylline on experimental skin flap survival in the domestic pig. Random skin flaps were designed using a length-width ratio of 5:1. The pigs were then given pentoxifylline (25 mg/kg/d) or placebo for seven days. Fluorescein sodium was used to help determine surviving skin flap length seven days postoperatively. Results showed no significant difference in mean surviving skin flap length between the study and control groups. We question the value of pentoxifylline in increasing skin flap survival.

Intravenous nitroglycerin as a means of improving ischemic tissue hemodynamics and survival.

The effects of intravenous nitroglycerin infusion on experimental skin flap survival and fluorescein dye kinetics were studied in animals. Perfusion fluorometry was utilized to examine changes in flap hemodynamics and viability. An improvement in skin flap survival was found in the nitroglycerin-infused animals, whether the nitroglycerin was initiated 30 minutes before or 30 minutes after flap elevation. Dye elimination in the flap appeared to be significantly improved with the drug therapy, indicating an improvement in flap blood flow with nitroglycerin.

Effects of low-power diode lasers on flap survival.

We investigated the effect of low-power laser irradiation on the survival of experimental skin flaps in rats. A gallium-aluminum-arsenide diode laser that was developed by the Japan Medical Laser Laboratory was used. The laser power was 15 mW and the wavelength 830 nm. Irradiation was carried out, either before or after flap elevation, in two groups of 20 Wistar strain rats. A third group of 20 rats served as controls. A caudally based skin flap, 3 X 9 cm, was designed on the back of each rat. Laser irradiation therapy was performed for 5 consecutive days for 6 minutes per flap per day, preoperatively in one group and postoperatively in the other. Seven days postoperatively, the survival areas of the flaps were measured and compared. The survival area was increased significantly in both groups receiving laser therapy, probably due to the observed proliferation of blood vessels around the irradiated points and an increase in blood flow.

Quantitation of skin-flap survival: a computer-based method.

We have proposed a standard scheme for presenting data on experimental skin flap survival in pharmacologic studies that will aid in comparing results. In addition, we have presented a method using desktop computer accessories for accurately measuring the area of any flap.

The effect of hyaluronidase and dimethyl sulfoxide (DMSO) on experimental skin flap survival.

Hyaluronidase has been shown clinically and experimentally to reduce the effects of tissue ischemia in myocardial infarction and hemorrhagic shock. Dimethyl sulfoxide (DMSO) has been shown to reverse the effects of cerebral ischemia in the primate model. A caudally based dorsal skin flap in the rat was used to study the effects of these two drugs in physiological doses on skin flaps, and to investigate their mechanisms of action. This study demonstrates that both hyaluronidase and DMSO, which are nontoxic in physiological doses, can increase the surviving length of an experimental skin flap. It is hypothesized that these substances exert their effect by decreasing tissue edema and by aiding in the transport of nutritive substances to the flap during its acute phase.

The effect of pulsed electromagnetic energy (DiapulseR) on the survival of experimental skin flaps

The effect of pulsed electromagnetic energy (DiapulseR) on the survival of experimental skin flaps

Effect of dipyridamole on the survival of experimental critical skin flaps.

The effect of dipyridamole (Persantin) on the survival of experimental skin flaps was studied. In controls 39% of the skin flap area survived. Intraperitoneal injection of dipyridamole 4 mg/kg twice daily starting four hours preoperatively increased the surviving area with 18%. This increase is statistically significant (p less than 0.05). The improved survival could be due to the vasodilatory action of the drug and/or proliferation of small bloodvessels induced by the drug.

Effect of Different Types of Anaesthesia Including Percutaneous Local Anaesthesia on Survival of Experimental Skin Flaps

Local anaesthesia by epicutaneous application of the ketocaine solution A2358 gave survival of experimental skin flaps in the guinea pig which corresponded on average to 71% of the total flap. The survival after pentobarbitone anaesthesia, general anaesthesia with ether, and infiltration of prilocaine without and with adrenalin varied between 41 and 53%. The difference in effect between percutaneous anaesthesia with A2358 and the other procedures was statistically significant (p less than 0.001). Epicutaneous application of A2358 followed by one of the other forms of anaesthesia gave a flap survival that did not differ from that following local anaesthesia with A2358 alone, except when followed by injection of prilocaine with adrenalin. The improved survival after epicutaneously applied A2358 is probably attributable to an effect on the peripheral vascular bed resulting in increasing blood supply and nutrition. It may be possible that A2358, for example, could be used in man as a complement to other forms of anaesthesia to provide enhanced tissue survival in skin flaps.

The Effect of Pulsed Electromagnetic Energy (Diapulse®) on the Survival of Experimental Skin Flaps: A Study on Rats

Experimental skin flaps in rats were treated with an active/non-active Diapulse unit in a double-blind trial to clarify whether or not pulsed electromagnetic energy had any effect on the surviving length of flaps. The observed differences in surviving flap areas between the Diapulse treated group and the untreated group as compared to the predicted survival by fluoresceine and/or vital capillary television microscopy were not statistically significant (p less than 0.10) in a set up, that on a significance level of 5%, would have detected an enhancement of flap survival of greater than or equal to 10% in 98% of trials.

Increased survival of experimental skin flaps in rats following treatment with antiadrenergic drugs.

The effect upon the survival of skin flaps of several drugs which affect the adrenergic system was studied in rats. In control animals 41% of the skin flaps had survived seven days after the operation. Reserpine (1 mg/kg) injected intraperitoneally (i.p.) three days and one day before the flap operation increased the surviving flap area by 75% (p less than 0.001) as compared to control rats injected with saline. I.p. injection of guanethidine (5 mg/kg) or bretylium (10 mg/kg) every 12 hours, starting 24 hours before surgery and continued for 5 consecutive days, also increased the surviving flap area (19 and 33% respectively p less than 0.001). The surviving flap area was unchanged when desipramine (5 mg/kg) was injected in the same way and was decreased by 15% (p less than 0.05) following i.p. injection of the MAO inhibitor pheniprazine (5 mg/kg). Treatment with alpha-methyl-p-tyrosine (75 mg/kg), i.p. 30 min before surgery or 6-hydroxydopamine (50 mg/kg) i.v. 24 hours prior to surgery also increased the flap survival (56 and 49% increase in surviving flap area, respectively, p less than 0.001). The results demonstrated that the survival of skin flaps increased when the function of the adrenergic nervous system was inhibited. Enhanced sympathetic nervous activity slightly reduced or did not affect skin flap survival.

Effect of phentolamine and propranolol on the survival of experimental skin flaps.

The effect of phentolamine and/or propranolol (alpha- and beta-receptor blocking compounds respectively) on the survival of skin flaps was studied in rats. Phentolamine and/or propranolol were injected intraperitoneally every 12 hours, starting one day before the flap operation, and continued for 5 consecutive days. One week after the operation the survival of the flaps was judged. Systemic treatment with either compound alone or in combination resulted in statistically significant increased survival of the flaps. The results demonstrate that both alpha- and beta-adrenergic receptors influence the survival of skin flaps in rats.

The effect of fractionated dose-patterns of X-radiation on the survival of experimental skin flaps in the pig.

Fields on the flanks of domestic swine were irradiated with 250 kVp X rays in courses of six fractions/18 days and 30 fractions/39 days. These fields were converted into full-thickness skin flaps from one week to six months after the last irradiation. Radiation damage to them was quantitated by measuring the length of flap that survived. As for irradiation with single doses, for these fractionated exposures there is a close correlation between the time at which the course of irradiation was begun and the time at which the survival of the skin flaps decreases. Implications for the combination of pre-operative radiotherapy with surgery in human cancer treatment are discussed.

The influence of stress on the survival of experimental skin flaps. A study on rats.

A skin flap of a size which could be expected to undergo partial necrosis was designed on the back of rats. Some animals were stressed postoperatively by repeated immobilization in order to increase plasma catechnolamine levels. Three groups were restrained and a control group received no postoperative treatment. One of the restrained groups received an adrenergic alpha-receptor blocking agent (phentolamine. Regitine® Sandoz) before and after each period of immobilization; another group was sham-injected at the same intervals. The survival of the skin flaps was compared for the different groups. In the restrained and sham-injected groups, survival was distinctly decreased compared with that in the control group, whereas the group given the adrenergic alpha-receptor blocking agent showed the best survival. The improved survival is ascribed to increased blood flow. This has earlier been shown to occur after alpha-receptor blockade in the sympathetically denervated and supersensitive blood vessels of similar...

The effects of hyperbaric oxygen, dimethyl sulfoxide and Complamin?? on the survival of experimental skin flaps

Dorsal standard skin flaps in rats were intentionally made long enough giving a predictable and constant degree of necrosis of the distal half of the flap. Six series of animals were treated with hyperbaric oxygen, dimethyl sulfoxide (DMSO) and Complamin respectively and compared with control series of untreated animals. The amount of surviving tissue was significantly increased by treatment with hyperbaric oxygen as well as with DMSO. All therapy used had, however, at best, a marginal effect on the survival of skin flaps in which the circulation had ceased. No support was found for the theory that necrosis of skin flaps occurs from an excess of arterial supply concomitant with an insufficient venous drainage.

The effects of hyperbaric oxygen, dimethyl sulfoxide and Complamin on the survival of experimental skin flaps.

Dorsal standard skin flaps in rats were intentionally made long enough giving a predictable and constant degree of necrosis of the distal half of the flap. Six series of animals were treated with hyperbaric oxygen, dimethyl sulfoxide (DMSO) and Complamin respectively and compared with control series of untreated animals. The amount of surviving tissue was significantly increased by treatment with hyperbaric oxygen as well as with DMSO. All therapy used had, however, at best, a marginal effect on the survival of skin flaps in which the circulation had ceased. No support was found for the theory that necrosis of skin flaps occurs from an excess of arterial supply concomitant with an insufficient venous drainage.

The effect of low molecular weight dextran on the survival of experimental skin flaps.

The effect of low molecular weight dextran on the survival of experimental skin flaps.