Unexpectedly high corneal flap thickness and ectasia after mechanical LASIK / Espessura inesperadamente alta do flap corneano e ectasia após LASIK mecânico

ABSTRACT LASIK is a refractive surgical procedure in which a corneal flap is created to expose the corneal stromal bed. Preoperative estimation of corneal flap thickness is necessary to calculate the percentage tissue altered in LASIK, an important quantitative risk factor for ectasia. The objective of this study was to assess flap thickness and calculate percentage tissue altered to check if unexpectedly thicker flaps and higher percentage tissue altered could pose as risk factors of ectasia. Four subjects (eight eyes) were submitted to mechanical LASIK in 2009 and 2010. Pre and postoperative clinical and tomographic data were reviewed. Mean preoperative estimated percentage tissue altered was 39.18±1.31%, which was borderline for increased ectasia risk when considering the limit of 40%. However, when considering the postoperatively measured flap thickness, the actual mean percentage tissue altered turned out to be 45.17 ± 4.13%, which was significantly higher than predicted preoperatively (p=0.002). Unexpectedly higher postoperative percentage tissue altered may be responsible for corneal ectasia after mechanical LASIK.

RESUMO A LASIK é um procedimento cirúrgico refrativo, no qual um retalho corneano é criado para expor o leito estromal corneano. A estimativa pré-operatória da espessura do retalho corneano é necessária para calcular o percentual de tecido alterado no LASIK, um importante fator de risco quantitativo para ectasia. O objetivo deste estudo foi avaliar a espessura do retalho e calcular o percentual de tecido alterado para verificar se retalhos inesperadamente mais espessos e percentuais de tecido alterado mais altos poderiam representar fatores de risco de ectasia. Quatro indivíduos (oito olhos) foram submetidos à LASIK mecânica em 2009 e 2010. Dados clínicos e tomográficos pré e pós-operatórios foram revisados. A média de percentual de tecido alterado pré-operatória estimada foi de 39,18±1,31%, limítrofe para risco aumentado de ectasia quando considerado o limite de 40%. No entanto, ao considerar a espessura do retalho medida no pós-operatório, o percentual de tecido alterado médio real foi de 45,17±4,13%, ou seja, significativamente maior do que o previsto no pré-operatório (p=0,002). O percentual de tecido alterado pós-operatóriao inesperadamente mais alto pode ser responsável pela ectasia da córnea após LASIK mecânico.

The effect of intradermal administration of inactive platelet-rich plasma on flap viability in rats

Abstract Purpose: To evaluate the effect of inactive form of platelet rich plasma (PRP) on the flap viability. Methods: Thirty six rats were used. Rats were divided into six groups then 9x3 cm random pattern skin flaps were elevated from dorsum of all rats. For precluding vascularization from the base, a silicone layer was placed under the flap in groups 2(only flap+silicone), 4(saline+silicone) and 6(PRP+silicone). In groups 1(only flap), 2(only flap+silicone) nothing was done except flap surgery. In groups 3(saline) and 4(saline+silicone), saline was applied intradermally , in groups 5(PRP) and 6(PRP+silicone), inactive form of PRP which obtained from different 16 rats was applied intradermally, into certain points of flaps immediately after surgery. After 7 days flap necrosis ratio was measured in all groups. Results: Mean necrosis rate in group 5(PRP) (16.05%) was statistically significantly lower than group 1(only flap) (31,93%) and group 3(saline) (30,43%) (p<0.001). Mean necrosis rate in group 6(PRP+silicone) (36.37%) was statistically significantly lower than group 2(only flap+silicone) (47.93%) and group 4(saline+silicone) (45.65%) (p<0.001). Conclusion: Intradermal inactive platelet rich plasma administration decreases flap necrosis so for skin application.

Avaliação de 40 ritidoplastias realizadas no Hospital Federal do Andaraí segundo duas técnicas distintas: smasplastia cervicofacial mediante sutura de vetores e retalho subSMAS / Evaluation of 40 rhytidoplasties performed at the Federal Hospital of Andaraí to compare two different techniques: cervicofacial SMAS-plasty according to vector suturing and the sub-SMAS flap approach

Introdução: A ritidoplastia se tornou uma das cirurgias estéticas mais realizadas no mundo. Alguns preferem uma abordagem mais conservadora e outros defendem que, para obter resultados mais duradouros e efetivos, necessitam de intervenções agressivas. O objetivo é comparar resultados de 40 ritidoplastias realizadas no Hospital Federal do Andaraí ao longo de 22 meses, utilizando duas técnicas distintas, smasplastia mediante sutura de vetores e retalho subSMAS. Métodos: Trata-se de um estudo descritivo em que 20 pacientes foram submetidas à smasplastia e outras 20 à retalho subSMAS. Um avaliador observou sob o ponto de vista estético algumas variáveis em regiões específicas da face e classificou a melhora baseado em fotografias pré-operatórias e 6 meses após o procedimento. A observação da ficha de coleta de dados possibilitou quantificar as complicações nas duas técnicas separadamente. Resultados: As duas técnicas demonstraram resultados semelhantes sob o ponto de vista estético com o objetivo de rejuvenescimento facial, melhora da flacidez cervical e definição da transição face/pescoço. Em especial, o retalho proporcionou melhores resultados na atenuação no sulco nasogeniano. Houve um caso de hematoma em cada técnica. Houve uma lesão nervosa na smasplastia. Não houve lesão do nervo facial, nem infecção. Edema superior a 3 meses foi mais prevalente naquelas submetidas ao retalho. Conclusões: Os dois métodos possuem vantagens e desvantagens e o melhor resultado depende do grau de envelhecimento do esqueleto facial, da perda de apoio de tecidos frouxos em áreas críticas como a região malar e próxima ao sulco labiomandibular, da característica de pele no pré-operatório e da experiência do cirurgião na técnica empregada.

Introduction: Rhytidectomy has become one of the most performed aesthetic surgeries in the world. Some surgeons prefer a more conservative approach, and others maintain that aggressive interventions are required to obtain results that are more durable and effective. This study aimed to compare the results of 40 rhytidectomies performed using either of two techniques, namely superficial musculoaponeurotic system (SMAS)-plasty according to vector suturing and the sub-SMAS flap approach, at the Federal Hospital of Andaraí over 22 months. Methods: This is a descriptive study that included 20 patients who underwent SMAS-plasty and 20 patients who received a sub-SMAS flap. An assessor identified some variables in specific regions of the face from an aesthetic point of view, and he rated improvements based on photographs obtained before and 6 months after operation. The data collected allowed to quantify complications of both techniques separately. Results: From an aesthetic point of view, the two techniques showed similar results in terms of facial rejuvenation, improvement of cervical flaccidity, and definition of face/neck transition. The flap provided better results regarding the attenuation in the nasogenian sulcus. A case of hematoma occurred in each technique. Nerve injury occurred in the SMAS-plasty group. However, neither facial nerve injury nor infection occurred in both groups . Edema for >3 months was more prevalent in the sub-SMAS flap group. Conclusions: The two methods have advantages and disadvantages, and the best result depended on the degree of aging of the facial skeleton, the loss of supporting tissues in critical areas such as the malar region and next to the labiomandibular fold, the preoperative characteristic of the skin, and the surgeon's experience in the technique.

Remote limb ischemic post-conditioning attenuates ischemia-reperfusion injury in rat skin flapby limiting oxidative stress

PURPOSE: To investigate the effect of remote ischemic post-conditioning (RIPoC) against ischemia-reperfusion (I/R) injury on flaps of rats. METHODS: Sprague-Dawley rats were randomized into the Sham, Control, RIPoC1 and RIPoC2 groups. All the animals were submitted to a 5×4 cm superficial inferior epigastric artery flap. Eight hours of flap ischemia was induced and two protocols of limb RIPoC were applied. Tissue MDA level and SOD activity in 24-h reperfusion were assessed. Flap survival was assessed 7 days postoperatively. RESULTS: Compared to the Control group, the RIPoC1 group showed statistically decreased MDA level at 6-, 12-, and 24-h reperfusion (P = 0.01, P < 0.01 and P < 0.01, respectively), and statistically increased SOD activity at 12- and 24-h reperfusion (P < 0.05 and P < 0.01, respectively). Flap survival rate on the 7th day was significantly higher in the RIPoC1 group than the control group (47.9 ± 6.4 vs . 29.4 ± 7.1 %, P < 0.01). CONCLUSION: Three cycles of 5-min Limb remote ischemic post-conditioning rather than a single cycle of 15-min limb RIPoC has protective effect on flaps against ischemia-reperfusion injury by attenuating oxidative stress.

Botulinum toxin type A on cutaneous flap viability in diabetic and tobacco-exposed rats

PURPOSE:To investigate the effect of Botulinum toxin A (BoNTA) on skin flap viability in healthy, tobacco-exposed and diabetic rats.METHODS: Ninety male Wistar rats (250-300g) were randomly divided into six groups: control+saline (C1), control+BoNTA (C2), tobacco-exposed+saline (T1), tobacco-exposed+BoNTA (T2) diabetes+saline (D1) and diabetes+BoNTA (D2). A dorsal cutaneous flap (3×10cm) was performed. Survival area and total area of the flaps were measured. Lumen diameter, external arterial diameter and lumen/wall thickness ratio were recorded.RESULTS: Survival area increased in control group with BoNTA injection compared with control animals injected with saline (C2 x C1; 0.9±0.1 vs0.67±0.15, p= 0.001). A similar result was found in diabetes group injected with BontA (D2 x D1; 0.97±0.2 vs0.61±0.24, p=0.018). No difference was observed in skin flap viability in tobacco-exposed groups (T2 x T1; 0.74±0.24 vs 0.64±0.21, p=0.871). Lumen diameter (p= 0.004), external arterial diameter (p = 0.0046,) and lumen/wall thickness ratio (p= 0.003) were increased in diabetes+BoNTA-treated animals. This effect was not observed in control or in tobacco-exposed groups.CONCLUSIONS:Botulinum toxin A increased skin flap viability in control and diabetic rats on the seventh post-operative day. Increased lumen diameter, external arterial diameter, and lumen/wall thickness ratio were observed in the diabetes+BoNTA group. BoNTA had no effect in the tobacco-exposed group on the seventh postoperative day.

Action of hyperbaric oxygenation in the rat skin flap

PURPOSE: To evaluate the morphology, necrotic area and collagen content in skin flaps of rats subjected to hyperbaric oxygenation (HBO). METHODS: Forty adult rats were divided into four groups: GEC - epilated; GE/HBO - epilated subjected to HBO; GER - epilated submitted to skin flap (2 cm in width /8 cm length in the dorsal area) and GER/HBO - epilated, subjected to skin flap and HBO. HBO (2.4 ATA) was performed for two hours during seven consecutive days. In the eighth day, the rats were anesthetized and the skin flaps were removed and separated into three portions, relative to pedicle fixation. The material fixed in 10% formalin was processed for paraffin embedding; sections were stained by H.E and subjected to picrosirius-red method. The slides examined under light microscopy for evaluation of the collagen content in polarized light microscope and ImageLab(r) software (Bio-Rad). RESULTS: The data showed larger area of necrosis and lower levels of collagen in the three regions of the GER group, whereas in the GER/HBO group the collagen content was similar to the GEC and GE/HBO groups. CONCLUSION: Hyperbaric oxygenation reduced the area of necrosis and preserved the morphology and collagen content in skin flaps of rats. .

Adipose-derived stem cells (ADSC) in the viability of a random pattern dorsal skin flap in rats

PURPOSE: To evaluate the viability of random pattern dorsal skin flaps in rats after injection of adipose-derived stem cells (ADSC). METHODS: Thirty five adult male Wistar EPM rats (weight 250-300 g) were distributed, at random, in two groups. I- Control (flap elevation with injection of saline solution) with fifteen animals and II- Experimental (flap elevation with injection of ADSC ) with fifteen animal. The ADSC were isolated from others five adult male rats. A dorsal skin flap measuring 10x4 cm was raised and a plastic barrier was placed between the flap and its bed in both groups and the injection (cells or saline solution) were perfomed immediately after the surgery. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The ADSC were able to replicate in our culture conditions. We also induced their adipogenic, osteogenic and chondrogenic differentiation to verify their mesenchymal stem cells potentiality in vitro. The results were statistically significant showing that the ADSC decreased the area of necrosis (p<0.05). CONCLUSIONS: The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro. The administration of adipose-derived stem cells was effective to increase the viability of the random random pattern dorsal skin flaps in rats. .

Adipose-derived stem cells (ADSC) in the viability of random skin flap in rats

PURPOSE: To evaluate the effects of the adipose-derived stem cells (ADSC) in the viability of random skin flap in rats. METHODS: Thirty five adult male Wistar rats (weight 250-300 g) were used. ADSC were isolated from adult male rats (n=5). ADSC were separated, cultured and then analyzed. A dorsal skin flap measuring 10x4 cm was raised and a plastic barrier was placed between the flap and its bed. After the surgical procedure, the animals were randomized into two groups (n=15 each group), group control and group ADSC. In all groups the procedures were performed immediately after the surgery. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The ADSC were able to replicate in our culture conditions. We also induced their adipogenic, osteogenic and chondrogenic differentiation, verifying their mesenchymal stem cells potentiality in vitro. The results were statistically significant showing that the ADSC decreased the area of necrosis (p<0.05). CONCLUSION: The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro. The administration of adipose-derived stem cells was effective to increase the viability of the random skin flaps in rats. .

Histological modification in TRAM flap in rats treated with pentoxifylline

PURPOSE: To investigate the blood vessels' concentration in TRAM flap's rat model, in the presence of pentoxifylline. METHODS: 32 male, Wistar-EPM rats were divided into two groups. Control group (C): 0.5 ml of saline, intraperitoneally, once a day, for seven days before flap elevation; PTX group (P): pentoxifylline (20mg/kg/day), intraperitoneally, for seven days before flap elevation. After that, they were submitted to a caudal unipedicle TRAM flap. On the fifth postoperative day, percentages of flap necrosis were determined via the "paper template" method and Tram flap's zone IV skin biopsies were taken for histological analysis. RESULTS: the mean percentage of flap necrosis in group C was 58.7 % and in group P, 31.1 (Wilcoxon test; p = 0.003). Mean capillary vessels number in zone IV's skin in C group was 33.4 and in P group was 71.9 (p=0.008). CONCLUSIONS: Pentoxifylline was effective reducing the necrosis in the caudal unipedicle TRAM flap in the rat as well as increasing the number of capillaries in an ischemic zone (zone IV). .

The influence of type of vascular pedicle occlusion on the viability of skin island flaps: a postoperative quantitative assessment of flap survival in an experimental model in rats

PURPOSE: To evaluate the role of pedicle occlusion on the viable area of a skin island flap. METHODS: An epigastric skin island flap was performed in 160 Wistar rats. The animals were randomly divided into four groups: G-1: occlusion of inferior epigastric artery; G-2: inferior epigastric vein; G-3: inferior epigastric vessels (artery/vein). At varying times postoperatively (2,3,4,5th day), animals from each group were randomly selected, and the pedicle was occluded. On the 10th. postop. day, the skin flaps were evaluated by templates to determine the percentage of surviving skin. The computer HP™ 9830A captured the photographs and the mean flap necrosis area was assessed. RESULTS: An increasing area of flap survived with less area of necrosis with increased time of days intervals. In the G-1, the mean area of necrosis observed (two to five days) were 95.2, 60.8, 31 and 3.7 % respectively. In the G-2 were 95.5, 57.6, 19.5 and 5.6 % respectively. In the G-3, a 100, 80, 32.4 and 14.9 % of mean area was observed. CONCLUSIONS: The arterial suppy/venous drainage is important for flap circulation up to five days following pedicle occlusion. After this period, the pedicle can be interrupted once the circulation through the flap margins has already been established.

The effects of local nitroglycerin on the surgical delay procedure in prefabricated flaps by vascular implant in rats / Efeitos da nitroglicerina tópica na autonomização de retalhos pré-fabricados por implante vascular em ratos

PURPOSE: To evaluate the effect of local nitroglycerin on the viable area of a prefabricated flap for vascular implant in rats, and to investigate the surgical delay procedure. METHODS: A femoral pedicle was implanted under the skin of the abdominal wall in forty Wistar rats. The animals were divided into four groups of ten: group 1 - without surgical delay procedure and local nitroglycerin; group 2 - with surgical delay procedure, but without local nitroglycerin; group 3 - without surgical delay procedure, but with local nitroglycerin; and group 4 - with simultaneous surgical delay procedure and local nitroglycerin. The percentages of the viable areas, in relation to the total flap, were calculated using AutoCAD R 14. RESULTS: The mean percentage value of the viable area was 8.9% in the group 1. 49.4% in the group 2; 8.4% in the group 3 and 1.1% in the group 4. There was significant difference between groups 1 and 2 (p=0.005), 1 and 4 (p=0.024), 2 and 3 (p=0.003), 2 and 4 (p=0.001). These results support the hypothesis that the closure of the arterial venous channels is responsible for the phenomenon of surgical delay procedure. CONCLUSION: Local nitroglycerin did not cause an increase in the prefabricated viable flap area by vascular implantation and decreased the viable flap area that underwent delay procedures.

OBJETIVO: Avaliar o efeito da nitroglicerina tópica sobre a área viável de um modelo de retalho pré-fabricado por implante vascular em ratos e analisar o mecanismo de autonomização cirúrgica aplicada a retalhos pré-fabricados. MÉTODOS: Foram utilizados 40 ratos Wistar. No primeiro tempo cirúrgico - 20 ratos foram submetidos a implante do pedículo femoral na região subdérmica da parede abdominal, e 20 submetidos à autonomização cirúrgica de retalho cutâneo de parede abdominal e, simultaneamente, implante do pedículo femoral na região subdérmica deste retalho. No segundo tempo - após três semanas e em todos os animais, era elevado um retalho cutâneo ilhado, pediculado unicamente nos vasos implantados e divididos em quatro grupos de dez animais: grupo 1, com retalhos submetidos unicamente a implante do pedículo femoral na região subdérmica da parede abdominal; grupo 2, com retalhos submetidos à autonomização cirúrgica e implante do pedículo femoral na região subdérmica deste retalho; grupo 3, com retalhos submetidos unicamente a implante do pedículo femoral na região subdérmica da parede abdominal tratados com nitroglicerina tópica; grupo 4, com retalhos submetidos à autonomização cirúrgica e implante do pedículo femoral na região subdérmica deste retalho tratados com nitroglicerina tópica. O percentual de área viável, em relação à área total do retalho, foi calculado sete dias após o segundo tempo cirúrgico. RESULTADOS: O valor médio de área viável alcançou 8,9% no grupo 1; 49,4% no grupo 2; 8,4% no grupo 3; e 1,1% no grupo 4. Houve diferença significante entre os grupos 1 e 2 (p=0,005); 1 e 4 (p=0,024); 2 e 3 (p=0,003) e 2 e 4 (p=0,001). Os resultados fortaleceram a hipótese de que o fechamento dos canais arteriovenosos é o principal mecanismo responsável pelo aumento da área viável observada em retalhos submetidos à autonomização cirúrgica.CONCLUSÃO: A nitroglicerina tópica não induziu ao aumento da área viável dos retalhos pré-fabricados por implante vascular e diminuiu a área viável dos retalhos submetidos à autonomização.

Structural alterations of foreskin caused by chronic smoking may explain high levels of urethral reconstruction failure using foreskin flaps

OBJECTIVES: The aim of the present study was to perform a stereological and biochemical analysis of the foreskin of smoker subjects. MATERIALS AND METHODS: Foreskin samples were obtained from 20 young adults (mean = 27.2 years old) submitted to circumcision. Of the patients analyzed, one group (n = 10) had previous history of chronic smoking (a half pack to 3 packs per day for 3 to 13 years (mean = 5.8 ± 3.2). The control group included 10 nonsmoking patients. Masson's trichrome stain was used to quantify the foreskin vascular density. Weigert’s resorcin-fucsin stain was used to assess the elastic system fibers and Picrosirius red stain was applied to study the collagen. Stereological analysis was performed using the Image J software to determine the volumetric densities. For biochemical analysis, the total collagen was determined as µg of hydroxyproline per mg of dry tissue. Means were compared using the unpaired t-test (p < 0.05). RESULTS: Elastic system fibers of smokers was 42.5% higher than in the control group (p = 0.002). In contrast, smooth muscle fibers (p = 0.42) and vascular density (p = 0.16) did not show any significant variation. Qualitative analysis using Picrosirius red stain with polarized light evidenced the presence of type I and III collagen in the foreskin tissue, without significant difference between the groups. Total collagen concentration also did not differ significantly between smokers and non-smokers (73.1µg/mg ± 8.0 vs. 69.2µg/mg ± 5.9, respectively, p = 0.23). CONCLUSIONS: The foreskin tissue of smoking patients had a significant increase of elastic system fibers. Elastic fibers play an important role in this tissue’s turnover and this high concentration in smokers possibly causes high extensibility of the foreskin. The structural alterations in smokers’ foreskins could possibly explain the poor results in smoking patients submitted to foreskin fasciocutaneous flaps in urethral reconstruction surgery.

The effects of different doses of 670 nm diode laser on skin flap survival in rats / O efeito de diferentes doses de laser de diodo 670 nm na viabilidade de retalho cutâneo randômico em ratos

PURPOSE: To investigate the effects of different low-level laser therapy (LLLT) doses on random skin flap rats. METHODS: Forty Wistar rats were randomly divided in four groups. The control group (CG) was not irradiated. The experimental groups were irradiated with a diode laser 670 nm with different energies per point: group 2 (G2) with 0.06 J; group 3 (G3) 0.15 J and group 4 (G4) 0.57 J. The three groups were irradiated in 12 equally distributed points in the cranial skin flap portion. They were submitted to the irradiation during the immediate, first and second postoperative days. The necrosis area was evaluated in the seventh postoperative day. RESULTS: The CG shows 49.35 percent of necrosis area in the skin flap; G2, 39.14 percent; G3, 47.01 percent and G4, 29.17 percent respectively. There was a significantly difference when G4 was compared with CG`s skin flap necrosis area. CONCLUSION: The low-level laser therapy diode 670 nm with 0.57 J energy per point increases the survival in randomic skin flap rats.

OBJETIVO: Investigar os efeitos de diferentes doses de laserterapia de baixa intensidade na viabilidade de retalhos cutâneos randômicos em ratos. MÉTODOS: Quarenta ratos Wistar foram randomizadamente distribuídos em quatro grupos. O grupo controle (GC) não foi irradiado. Os animais dos grupos experimentais foram irradiados por laser de diodo (670 nm) com as seguintes energias ofertadas por ponto: grupo 2 (G2) 0,06J; grupo 3 (G3) 0,15 J e grupo 4 (G4) 0,57 J. Os três grupos foram irradiados em 12 pontos igualmente distribuídos na porção cranial do retalho cutâneo. Todos os animais dos grupos 2, 3 e 4 foram submetidos ao protocolo de irradiação por três dias consecutivos, iniciando no pós-operatório imediato. A área necrótica foi avaliada no sétimo dia pós-operatório. RESULTADOS: A porcentagem de área necrótica apresentou-se da seguinte forma, nos diferentes grupos: GC= 49,35 por cento, G2= 39,14 por cento, G3= 47,01 e G4= 29,17 por cento. Foi encontrada diferença estatisticamente significante quando se compararam os dados entre GC e G4. CONCLUSÃO: A irradiação com laser de diodo (670 nm) de baixa intensidade, com oferta de 0,57 J de energia por ponto influenciou positivamente a viabilidade de retalhos cutâneos randômicos em ratos.

Effects of sildenafil on the viability of random skin flaps / Os efeitos do sildenafil na viabilidade de retalhos cutâneos randômicos

PURPOSE: To assess the viability of McFarlane skin flaps in rats with administration of sildenafil. METHODS: Twenty Wistar rats were distributed into two groups: Control (dorsal skin flap, subdermal application of saline solution at 0.9 percent) and Study (dorsal skin flap, subdermal application of sildenafil). Seven days after the surgery, flaps were photographed and graphically rendered. Then, they were analyzed with AutoCAD software. Three biopsies (proximal, medial and distal) of each flap were collected for histological analysis. RESULTS: Macroscopic analysis showed that animals of the study group had greater necrotic areas (p=0.003) in the dorsal skin flaps. Additionally, histological analysis of the distal third of these flaps showed a tendency to less granulated tissue formation in animals treated with sildenafil. CONCLUSION: Sildenafil subdermally was associated with lower viability of the random skin flap in rats.

OBJETIVO: Avaliar a viabilidade de retalhos cutâneos de ratos à McFarlane após a administração de sildenafil. MÉTODOS: Vinte ratos Wistar foram distribuídos em dois grupos: Controle (confecção do retalho cutâneo dorsal, aplicação subdérmica de solução salina a 0,9 por cento) e Estudo (confecção do retalho cutâneo dorsal, aplicação subdérmica de sildenafil). Sete dias após a operação, os retalhos foram fotografados e representados graficamente, para serem analisados com o programa AutoCad. Três biópsias (cranial, média e caudal) foram coletadas de cada retalho, para análise histológica. RESULTADOS: A análise macroscópica evidenciou que os animais do grupo Estudo apresentaram maiores áreas de necrose (p=0,003) nos retalhos cutâneos dorsais. Além disso, a análise histológica dos terços distais dos retalhos mostrou uma tendência à formação de menos tecido de granulação nos animais que receberam o sildenafil. CONCLUSÃO: O sildenafil subdérmico esteve associado com uma pior viabilidade tecidual dos retalhos cutâneos dorsais de ratos.

Adipocyte morphometric evaluation and angiogenesis in the omentum transposed to the breast: a preliminary study

OBJECTIVE: The purpose of this study was to describe the probable mechanism of the volume increase of laparoscopically harvested omentum flaps used to treat breast deformities. METHODS: A histological analysis of omentum samples was performed to study the volume increase of laparoscopically harvested omentum flaps. Samples were harvested immediately after the transposition of the omentum from the abdominal cavity to the breast region and during the second surgical procedure for breast symmetrization of eight patients submitted to the transposition of the omentum flap. Changes in the morphometric measurements of the adipocytes (perimeter, diameter, and area), microvascular density (as measured by the CD31 endothelial marker), and immunohistochemical expression of VEGF were documented. RESULTS: The increases in adipocyte size and microvascular density were statistically significant (P < 0.012). The expression levels of VEGF were lower in the second set of samples when compared to the first set, but the differences were not statistically significant (P < 0.093). CONCLUSION: These results demonstrate an increase in cellular volume as measured by adipocyte perimeter, diameter, and area. Moreover, the increase in the number of vessels in the second set of samples suggests that neoangiogenesis was stimulated by the initial increase in VEGF expression levels observed in the first set of samples. The increase in VEGF expression in the flap may have been caused by adipocyte hypertrophy resulting from neoangiogenesis.

Pectoralis major myocutaneous flaps for head and neck reconstruction: factors influencing occurrences of complications and the final outcome / Retalho miocutâneo de peitoral maior em reconstruções de cabeça e pescoço: fatores que influenciam a ocorrência de complicações e o resultado final

CONTEXT AND OBJECTIVE: Pedicled flaps play an important role in cancer treatment centers, particularly in developing and emerging countries. The aim of this study was to identify factors that may cause complications and influence the final result from reconstructions using pectoralis major myocutaneous flaps (PMMFs) for head and neck defect repair following cancer resection. DESIGN AND SETTING: Cross-sectional study at the Hospital de Ensino Padre Anchieta of Faculdade de Medicina do ABC (FMABC). METHODS: Data on 58 patients who underwent head and neck defect reconstruction using PMMFs were reviewed. The final result from the reconstruction (success or failure) and the complications observed were evaluated in relation to the patients' ages, area reconstructed, disease stage, previous oncological treatment and need for blood transfusion. RESULTS: There were no total flap losses. The reconstruction success rate was 93.1 percent. Flap-related complications occurred in 43.1 percent of the cases, and half of them were considered major. Most of the complications were successfully treated. Defects originating in the hypopharynx were correlated with the development of major complications (p = 0.02) and with reconstruction failure (p < 0.001). Previous oncological treatment negatively influenced the reconstruction success (p = 0.04). CONCLUSIONS: Since the risk factors for developing major complications and reconstruction failure are known, it is important to heed the technical details and provide careful clinical support for patients in a more critical condition, so that better results from using PMMFs can be obtained.

CONTEXTO E OBJETIVO: Retalhos pediculados têm grande importância nos centros de tratamento do câncer, principalmente em países emergentes e em desenvolvimento. O objetivo deste trabalho foi identificar fatores que determinam complicações e influenciam no resultado final das reconstruções com retalho miocutâneo de peitoral maior (RMPM) no reparo de defeitos cirúrgicos por ressecções de cânceres de cabeça e pescoço. TIPO DE ESTUDO E LOCAL: Estudo transversal no Hospital de Ensino Padre Anchieta da Faculdade de Medicina do ABC. MÉTODOS: Dados de 58 pacientes submetidos a reconstruções de defeitos de cabeça e pescoço com RMPM foram revisados. O resultado final da reconstrução (sucesso ou falha) e as complicações observadas foram avaliados de acordo com a idade do paciente, área reconstruída, estágio da doença, tratamento oncológico prévio e necessidade de transfusão sanguínea. RESULTADOS: Não houve perda total de retalho. A taxa de sucesso da reconstrução foi de 93,1 por cento. Complicações relacionadas ao retalho ocorreram em 43,1 por cento dos casos e 50 por cento delas foram considerados como complicações maiores. A maioria das complicações foi tratada com sucesso. Os defeitos originados da hipofaringe relacionaram-se com o desenvolvimento de complicações maiores (p = 0,02) e falhas na reconstrução (p < 0,001). Tratamento oncológico prévio influenciou negativamente no sucesso da reconstrução (p = 0,04). CONCLUSÕES: Como os fatores de risco para o desenvolvimento de complicações maiores e de falha na reconstrução são conhecidos, é importante atentar para detalhes técnicos e empregar suporte clínico cuidadoso aos pacientes mais críticos para que sejam obtidos melhores resultados com o uso do RMPM.

Capsaicin on the viability of random-pattern skin flaps in rats / Capsaicina na viabilidade de retalhos isquêmicos randômicos em ratos

PURPOSE: To evaluate the effects of capsaicin on the viability of ischemic random-pattern skin flaps in rats. METHODS:Forty EPM1-Wistar rats were randomized into two groups of 20 animals each, the capsaicin group and the control group. A random-pattern skin flap measuring 10 x 4cm was raised and a plastic barrier was placed between the flap and the donor site. After the surgical procedure, the control group was treated with an inert vehicle in the form of a cream applied uniformly to a rayon bandage which, in turn, was applied to the surface of the skin flap. The capsaicin group was treated in the same way, but in this case capsaicin was added to the cream. This procedure was repeated for two consecutive days. RESULTS: There was a significantly smaller amount of flap necrosis in the capsaicin group (35.07 percent) than in the control group (44.75 percent) (p=0.035). CONCLUSION:Topical administration of capsaicin improved the viability of ischemic random-pattern skin flaps in rats.

OBJETIVO: Avaliar os efeitos da capsaicina na viabilidade de retalhos isquêmicos randômicos em ratos. MÉTODOS: Quarenta ratos EPM1-Wistar foram distribuídos ao acaso em dois grupos de 20 animais cada, um grupo capsaicina e um grupo controle. Um retalho isquêmico randômico medindo 10 x 4cm foi elevado e uma barreira plástica foi colocada entre o retalho e a área doadora. Após o procedimento cirúrgico, o grupo controle foi tratado com um veículo inerte sob a forma creme aplicado uniformemente sobre uma atadura de rayon, que, por sua vez, foi aplicada à superfície do retalho. O grupo capsaicina foi tratado da mesma forma, porém a capsaicina foi adicionada ao creme. Este procedimento foi repetido por dois dias consecutivos. RESULTADOS: Houve uma quantidade significativamente menor da necrose do retalho no grupo capsaicina (35,07 por cento) comparado ao grupo controle (44,75 por cento) (p=0,035). CONCLUSÃO: A administração tópica da capsaicina melhorou a viabilidade de retalhos isquêmicos randômicos em ratos.

Nicotine on rat TRAM flap / Nicotina em retalho TRAM em ratos

PURPOSE: The transverse rectus abdominis myocutaneous (TRAM) flap is one of the preferential techniques used in breast reconstruction following mastectomy. Nicotine has a detrimental effect on cutaneous flap survival; although there are no experimental studies proving this effect on musculocutaneous flaps. The aim of this study is to verify the effect of nicotine on the rat TRAM flap. METHODS: 30 Wistar EPM-1 rats were randomly distributed in two groups: control and experimental. The animals of the control group received saline solution injected subcutaneously, in a volume of 0.2 ml, twice a day, during 28 days in the preoperative period. The animals of the experimental group were treated with nicotine, injected subcutaneously, in a dose of 2 mg/kg twice a day, during 28 days in the preoperative period. All the animals were submitted to the caudally based, right unipedicled TRAM flap. 48 hours after the procedure, a study of the viable area of the flap was done through photographic documentation. Statistical analysis was performed with nonparametric Mann-Whitney's test. RESULTS: The experimental group had significantly greater area of necrosis when compared with the control group (p<0.001). CONCLUSION: Nicotine increased the area of necrosis of the TRAM flap, in rats.

OBJETIVOS: O retalho musculocutâneo transverso do músculo reto do abdome (TRAM) é uma das principais opções na reconstrução do relevo mamário pós-mastectomia. A nicotina tem efeito deletério na viabilidade de retalhos cutâneos; porém, não foram encontrados trabalhos experimentais comprovando este efeito em retalhos musculocutâneos. O objetivo deste trabalho é investigar o efeito da nicotina na viabilidade do retalho TRAM, em ratos. MÉTODOS: Foram utilizados 30 ratos da linhagem Wistar EPM-1. Os animais foram distribuídos aleatoriamente em dois grupos: controle e experimento. Os animais do grupo controle foram tratados com solução salina injetada no tecido celular subcutâneo num volume de 0,2 ml, duas vezes ao dia, durante 28 dias no período pré-operatório. Os animais do grupo experimento foram tratados com nicotina injetada no tecido celular subcutâneo em uma dose de 2mg/kg/2 vezes ao dia, durante 28 dias no período pré-operatório. Todos os animais foram submetidos ao procedimento do retalho TRAM de base caudal unilateral à direita (pedículo não dominante). 48 horas depois, foi feita a avaliação da área viável de superfície do retalho, por documentação fotográfica. Para análise dos resultados foram utilizados testes não paramétricos: Mann-Whitney. RESULTADOS: O grupo experimento apresentou uma área de necrose maior, quando comparado com o grupo controle (p<0,001). CONCLUSÃO: A nicotina aumentou a área de necrose do retalho TRAM, em ratos.

Histamine iontophoresis on the viability of random skin flap in rats / Iontoforese de histamina na viabilidade do retalho cutâneo randômico em ratos

PURPOSE: To evaluate the effects of the histamine iontophoresis on the random skin flap viability in rats. METHODS: Sixty adult male Wistar rats were used. A cranially-based dorsal skin flap measuring 10 x 4 cm was raised and a plastic barrier was placed between the flap and its bed. After the surgical procedure, the animals were randomized into four groups (G1-G4) (n=15 each group) as follows: G1 (control) - sham electrical stimulation, G2 (electrical stimulation) - direct current electrical stimulation, G3 (histamine) - histamine and sham electrical stimulation and G4 (histamine iontophoresis) - transdermal iontophoresis of histamine. In all groups the procedures were performed immediately after the surgery and on the two subsequent days. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The mean and the respective standard deviation of the percentage of flap necrosis areas were as follows: G1 (control) - 47.87 ± 9.13 percent, G2 - 51.49 ± 8.19 percent, G3 - 46.33 ± 8.32 percent and G4 - 30.82 ± 11.25 percent. The G4 group presented a significantly smaller amount of flap necrosis when compared to the other groups (p<0.001). CONCLUSION: The topical administration of the histamine by iontophoresis was effective to increase the viability of the random skin flaps in rats.

OBJETIVO: Avaliar o efeito da iontoforese de histamina na viabilidade do retalho cutâneo randômico em ratos. MÉTODOS: Foram utilizados 60 ratos adultos e machos da linhagem Wistar. O retalho cutâneo de base cranial, medindo 10x4 cm, foi elevado no dorso dos animais e uma barreira plástica foi interposta entre o retalho e a área doadora. Após o procedimento operatório, os animais foram distribuídos aleatoriamente em 4 grupos (G1-G4) (n=15 em cada grupo) a saber: G1 (controle) - simulação da estimulação elétrica, G2 (estimulação elétrica) - estimulação elétrica com corrente direta, G3 (histamina) - histamina e simulação da estimulação elétrica e G4 (iontoforese de histamina) - iontoforese transdérmica de histamina. Em todos os grupos os procedimentos foram realizados imediatamente após a operação e nos 2 dias subseqüentes. A porcentagem de área de necrose foi avaliada no 7º dia pós-operatório. RESULTADOS: As médias e respectivos desvios-padrão das porcentagens de área de necrose foram: G1 (controle) - 47,87 ± 9,13 por cento, G2 - 51,49 ± 8,19 por cento, G3 - 46,33 ± 8,32 por cento and G4 - 30,82 ± 11,25 por cento. O grupo G4 apresentou menor média de área de necrose quando comparado aos demais grupos (p<0,001). CONCLUSÃO: A administração tópica de histamina por iontoforese aumentou a viabilidade do retalho cutâneo randômico em ratos.

Estudo da ação da estreptoquinase e do alopurinol em retalhos cutâneos em ilha submetidos à isquemia prolongada: estudo experimental em ratos / Study of the effect of streptokinase and allopurinol in island skin flaps submitted to prolonged ischemia: experimental study in rats

OBJETIVO: Estabelecer relação entre a sobrevivência de retalhos cutâneos em ilha submetidos à isquemia prolongada e o uso da estreptoquinase e do alopurinol administrados após o período de isquemia prolongado. MÉTODOS: Foram utilizados 48 ratos machos da raça Wistar, com peso entre 300 e 350g, divididos em quatro grupos com 12 cada um, sendo; grupo controle, alopurinol, estreptoquinase e associação de alopurinol com estreptoquinase, submetidos à dissecção de retalho epigástrico em ilha, seguido de clampeamento do feixe vascular, por oito horas em isquemia mista normotérmica. Após este período, as pinças foram retiradas e cada animal recebeu o esquema terapêutico proposto através de injeção intravenosa. A análise da sobrevivência dos retalhos foi realizada no sétimo dia de pós-operatório. Foram realizadas análises descritivas ( por cento de área necrótica) e de variâncias, bem como comparações múltiplas de Dunnett T3 entre os quatro grupos e o teste da mediana. RESULTADOS: O grupo controle apresentou em média 79,88 por cento de necrose da área total. Aqueles que receberam alopurinol apresentaram em média 64,05 por cento de necrose e o grupo que recebeu estreptoquinase apresentou em média 55,52 por cento de necrose. Com a associação das duas drogas, os ratos apresentaram 54,30 por cento em média de necrose do retalho. Aplicando o teste Dunnett e o teste da mediana verificou-se de que o grupo estreptoquinase é o com menor percentual de necrose neste estudo. CONCLUSÃO: A administração sistêmica da estreptoquinase após oito horas de isquemia mista normotérmica resultou em aumento da sobrevivência de retalhos epigástricos em ilha em ratos, quando comparada à administração de alopurinol, associação do alopurinol e estreptoquinase e do grupo controle.

BACKGROUND: To establish a relation between the survival rate of island skin flaps submitted to prolonged ischemia and the effect of streptokinase and allopurinol administered after the ischemic period. METHODS: A total of 48 male Winstar rats, each weighing between 300 and 350 grams,were separated into four groups of twelve as follows: control, allopurinol, streptokinase and association of allopurinol and streptokinase, were submitted to an epigastric island flap dissection followed by epigastric vessel bundle clamping. Flaps remained this way for 8 hours in normothermic mixed ischemia. After the ischemic period, clamps were removed and each rat received the therapeutical scheme proposed for the group by intravenous injections. Flap survival analysis was performed on the seventh post operative day. Variance and descriptive analyses (as a percentage of the necrotic area) as well as Dunnett-T3 multiple comparisons among the 4 groups and median tests were carried out. RESULTS: Rats in the control group presented an average of 79.88 percent of necrosis in the flap total area; those which received allopurinol presented an average of 64.05 percent of necrosis whereas the group which received streptokinase showed an average of 55.52 percent of necrosis. With the association of both drugs, rats presented an average of 54.30 percent of necrosis in the flap total area. By applying Dunnet test and the median test, it could be verified that, in this study the streptokinase group had the lowest necrosis rate. CONCLUSION: The systemic administration of streptokinase after 8 hours of normothermic global ischemia resulted in an increased survival rate of epigastric island skin flaps in rats, when compared to the administration of allopurinol, association of the two drugs and the control group.