RESUMO
OBJECTIVE: The aim of this study was to assess and compare the effects of laser phototherapy (LPT) on cutaneous flaps on diabetic rats. BACKGROUND: Diabetes mellitus is characterized by high blood glucose levels. Its main complications are delayed wound healing, an impaired blood supply, and a decrease in collagen production. Cutaneous flaps are routinely used in several surgical procedures, and most failures are related to poor blood supply. LPT has been studied using several healing models. ANIMALS AND METHODS: Twelve Wistar rats were randomized into three groups: group 1 (G1; diabetic animals without treatment), group 2 (G2; diabetic animals irradiated with lambda680 nm), and group 3 (G3; diabetic animals irradiated with lambda790 nm). Diabetes was induced with streptozotocin. A 2- x 8-cm cutaneous flap was raised on the dorsum of each animal, and a plastic sheet was introduced between the flap and the bed to cause poor blood supply. Nonirradiated animals acted as controls. The dose per session was 40 J/cm(2). Laser light was applied transcutaneously and fractioned on 16 contact points at the wound margins (16 x 2.5 J/cm(2)). Animal death occurred on day 8 after surgery. Specimens were taken, processed, cut, stained with eosin (HE) and sirius red, and underwent histological analysis. RESULTS: It is shown that accute inflammation was mostly discrete for G3. Chronic inflammation was more evident for G2. Fibroblast number was higher for G3. Angiogenesis was more evident for G3. Necrosis was more evident for G2. Statistical analysis among all groups showed significant differences (p = 0.04) on the level of acute inflammation between G1 and G3, tissue necrosis between G1 and G2 (p = 0.03), chronic inflammation between (p = 0.04), fibroblastic proliferation between G2 and G3 (p = 0.05), and neovascularization between G2 and G3 (p = 0.04). CONCLUSION: LPT was effective in increasing angiogenesis as seen on irradiated subjects and was more pronounced when IR laser light was used.
Assuntos
Diabetes Mellitus Experimental , Sobrevivência de Enxerto/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Retalhos Cirúrgicos , Animais , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
BACKGROUND AND OBJECTIVE: Some studies have shown that laser phototherapy is able to increase skin flap viability by decreasing the necrotic area and increasing neoangiogenesis. However, the mechanism by which laser acts on cells is not fully understood. The present study investigated the effects of two different laser wavelengths at 30 and 40 J/cm(2) on the viability of skin flap in rats. MATERIAL AND METHODS: Sixty male animals were used in this study. They were distributed into the following groups (n = 12 each group): control group, group irradiated with 660 nm at 30 J/cm(2); group irradiated with 780 nm, at 30 J/cm(2), group irradiated with 660 nm at 40 J/cm(2); and group irradiated with 780 nm at 40 J/cm(2). The skin flap was performed on the back of all animals studied, with a plastic sheet interposed between the flap and the donor site. Laser irradiation was done immediately after the surgery and on days 1, 2, 3, and 4 post-surgery. The percentage of the necrotic area of the flap was calculated at day 7 post-surgery. RESULTS: Control group showed a necrotic area of 62.83%. Interestingly, no statistically significant differences were found among the treated groups and the control group. CONCLUSION: This present study showed that 660 nm and 780 nm lasers at doses of 30 and 40 J/cm(2) were not effective for decreasing the necrotic area of the skin flaps in rats.
Assuntos
Terapia com Luz de Baixa Intensidade , Pele/efeitos da radiação , Retalhos Cirúrgicos , Sobrevivência de Tecidos/efeitos da radiação , Animais , Modelos Animais de Doenças , Sobrevivência de Enxerto/efeitos da radiação , Masculino , Necrose , Ratos , Ratos Wistar , Pele/patologia , Cicatrização/efeitos da radiaçãoRESUMO
OBJECTIVE: To assess the effect of low-level laser therapy (LLLT) on viability of mast cells of the transverse rectus abdominis musculocutaneous (TRAM) flap. BACKGROUND DATA: LLLT has been recently used on the TRAM flap to stimulate mast cells. MATERIALS AND METHODS: Eighty-four Wistar rats were randomly divided into seven groups of 12 rats in each: group 1 (sham laser therapy); group 2 received 3 J/cm(2) at one point; group 3 received 3 J/cm(2) at 24 points; group 4 received 72 J/cm(2) at 1 point; group 5 received 6 J/cm(2) at 1 point; group 6 received 6 J/cm(2) at 24 points; and group 7 received 144 J/cm(2) at 1 point. All experimental groups underwent LLLT immediately after TRAM surgery and on the next two following days, for three sessions in total. The percentage of the area of skin flap necrosis was calculated on the fourth postoperative day and two samples of skin were collected from each rat with a 1-cm(2) punch to perform mast cell evaluations with toluidine blue dye. RESULTS: Statistically significant differences were found in the percentage of necrosis, and higher values were seen in group 1 than in all other groups. Among groups 3-7 no statistically significant differences were found (p < 0.292). For mast cells, when group 1 was compared to groups 5 (6 J/cm(2) at 1 point) and 7 (144 J/cm(2) at 1 point), it had fewer mast cells. CONCLUSION: LLLT at a wavelength of 670 nm was effective at reducing the necrotic area, and we found that it can stimulate mast cells growth to increase vascular perfusion.
Assuntos
Sobrevivência de Enxerto/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Mastócitos/efeitos da radiação , Retalhos Cirúrgicos/irrigação sanguínea , Animais , Sobrevivência Celular/efeitos da radiação , Masculino , Modelos Animais , Ratos , Ratos Wistar , Reto do Abdome/efeitos da radiação , Pele/efeitos da radiaçãoRESUMO
OBJECTIVE: This study aimed to investigate the effect of diode laser (830 nm) irradiation on the viability of ischemic random skin flaps in rats, as well as to determine the most effective site for applying laser radiation to speed healing. BACKGROUND DATA: Low-level laser therapy (LLLT) has recently been used to improve the viability of ischemic random skin flaps in rats. MATERIALS AND METHODS: Seventy Wistar rats were used and divided into seven groups of 10 rats each: group 1, sham laser treatment; group 2, which received irradiation at 1 point 5 cm from the flap's cranial base; group 3, which received irradiation at 2 points (5 and 7.5 cm from the flap's base); group 4, which received irradiation at 3 points (2.5, 5 and 7.5 cm from the flap's base); group 5, which received irradiation at 1 point 2.5 cm from the flap's base; group 6, which received irradiation at 2 points (2.5 and 5 cm from the flap's base); and group 7, which received irradiation at 1 point 7.5 cm from the flap's base. The animals were subjected to laser therapy at an energy density of 36 J/cm(2) for 72 sec immediately after surgery, and one time on each of the four subsequent days. The percentage of necrotic skin flap area was calculated on the seventh postoperative day using a paper template. RESULTS: The results showed that the rats in group 5 had the highest increase in skin flap viability, with a statistically significant difference compared to the other groups. Statistically significant differences were not seen between any of the other groups. CONCLUSION: The diode laser was effective in increasing skin flap viability in rats, and laser irradiation of a point 2.5 cm from the cranial base flap was found to be the most effective.
Assuntos
Terapia com Luz de Baixa Intensidade , Pele/efeitos da radiação , Retalhos Cirúrgicos/irrigação sanguínea , Cicatrização/efeitos da radiação , Análise de Variância , Animais , Sobrevivência Celular/efeitos da radiação , Sobrevivência de Enxerto/efeitos da radiação , Lasers Semicondutores , Terapia com Luz de Baixa Intensidade/instrumentação , Masculino , Modelos Animais , Necrose , Ratos , Ratos WistarRESUMO
Free tissue transfer of a jejunal segment was undertaken for laryngopharyngoesophageal reconstruction in 20 patients who received postoperative irradiation therapy. Treatment consisted of 1.8- to 2-Gy-fractions, the average total dose was 55.57 Gy (range, 40 to 66 Gy). Anastomotic strictures (six) were encountered early in the series and associated with stapled anastomoses. Hand-sewing the jejunoesophagostomy eliminated the problem. Enteric cutaneous fistula, bowel necrosis, and hemorrhagic enteritis were not observed. We conclude that the application of postoperative irradiation therapy to patients requiring jejunal interposition grafts is feasible.