Effect of short-term ischemia on microcirculation and wound healing of adipocutaneous flaps in the rat

Abstract Purpose Composite flaps used in reconstructive surgery may intra- and postoperatively suffer from hypoperfusion and/or ischemia-reperfusion influencing wound healing. We aimed to follow-up the effect of ischemia on adipocutaneous flaps' wound healing and microcirculation. Methods In anesthetized rats groin flaps were formed bilaterally. In Control group the flaps were repositioned and sutured back. In Ischemia-Reperfusion (I/R) group before repositioning and suturing the flap pedicles were clamped for 60 minutes. Laser Doppler (LD) fluxmetry and temperature probes were applied on the cranial, central and caudal flap regions before/after preparation and ischemia, re-suturing, and on the 1st-3rd-5th-7th-14th postoperative days, before the final examinations and biopsies for histology. Results Flaps' skin temperature quickly recovered after repositioning. LD values were lower in the I/R group, reaching a significant level by the 3rd postoperative day, and remained lowered till the 14th day. The magnitude of alterations differed in the flap regions. Histologically normal wound healing process was seen, except for some I/R flaps, where hypertrophized mammary glands were found. Conclusions Short-term ischemia could influence flap microcirculation and wound healing, and may result in hypertrophized mammary glands. Laser Doppler could be used to evaluate intra- and postoperative microcirculatory changes and may have significance in predicting complications.

Reconstrucción mamaria con colgajo musculocutáneo de recto abdominal con isla transversa de piel (TRAM): experiencia de 12 años en Hospital El Pino / Breast reconstruction with musculocutaneous flap of abdominal rectus with transverse skin island (TRAM): 12 years of experience at Hospital El Pino

Objetivos: Analizar los resultados de reconstrucción mamaria con colgajo musculocutáneo de recto abdominal con isla transversa de piel (TRAM) en el Servicio de Cirugía del Hospital El Pino. Materiales y Métodos: Estudio retrospectivo de pacientes sometidas a mastectomía por cáncer de mama y posterior reconstrucción con colgajo TRAM pediculado en los últimos 12 años (2005-2017). Resultados: Se realizaron 12 reconstrucciones mamarias, 6 fueron con colgajo TRAM pediculado. La mayoría de las pacientes recibieron tratamiento adyuvante con radioterapia (1 caso), quimioterapia (1 caso), quimioterapia + radioterapia (2 casos). El tiempo transcurrido entre la mastectomía y reconstrucción mamaria fue en promedio de 2,5 años. Se produjeron 4 complicaciones (66,7%) que necesitaron reintervención: hematoma posoperatorio precoz, infección y necrosis grasas de colgajo, dehiscencia de sutura abdominal, necrosis grasa + fibrosis de colgajo TRAM. La evaluación de los resultados fue subjetiva obteniéndose muy buenos resultados en el 66,7% de los casos. No hubo complicaciones en sitio donante. Discusión: El colgajo TRAM pediculado es el tejido autólogo más utilizado en reconstrucción mamaria. Su tasa de complicación es de 26% muy por debajo a lo obtenido en nuestra experiencia. Las principales complicaciones son fibrosis y necrosis grasa de colgajo, pérdida de colgajo, seroma e infección siendo la necrosis grasa la más frecuente en nuestra serie. El uso de colgajo TRAM otorga mayor satisfacción con apariencia, tamaño y sensación del seno. Debido a los resultados obtenidos creemos que el colgajo TRAM pediculado es una excelente alternativa de reconstrucción mamaria en nuestro hospital.

Objectives: To analyze the results of breast reconstruction with musculocutaneous flap of the rectus abdominis with transverse skin island (TRAM) in the Service of Surgery of El Pino Hospital. Materials and Methods: Retrospective study of patients undergoing mastectomy for breast cancer and subsequent reconstruction with pedicled TRAM flap in the last 12 years (2005-2017). Results: 12 mammary reconstructions were performed, 6 were with pedicled TRAM flap. The majority of patients received adjuvant treatment with radiotherapy (1 case), chemotherapy (1 case), chemotherapy + radiotherapy (2 cases). The time elapsed between the mastectomy and breast reconstruction was on average 2.5 years. There were 4 complications (66.7%) that required reintervention: early postoperative hematoma, infection and flap fat necrosis, abdominal suture dehiscence, fat necrosis + TRAM flap fibrosis. The evaluation of the results was subjective, obtaining very good results in 66.7% of the cases. There were no complications in the donor site. Discussion: The pedicled TRAM flap is the most used autologous tissue in breast reconstruction. Its complication rate is 26%, much lower than that obtained in our experience. The main complications are fibrosis and flap fat necrosis, flap loss, seroma and infection, with fat necrosis being the most frequent in our series. The use of TRAM flap gives greater satisfaction with appearance, size and sensation of the breast. Due to the results obtained, we believe that the pedicled TRAM flap is an excellent alternative for breast reconstruction in our hospital.

Glucose level evaluation in monopedicled rectus abdominis myocutaneous flap after venous occlusion: experimental study in rats / Avaliação do nível glicêmico em retalho miocutâneo do reto abdominal monopediculado após oclusão venosa: estudo experimental em ratos

ABSTRACT Objective: to validate an experimental model for the measurement of glycemic levels in surgical flaps with the use of common glucometers, and to analyze the diagnostic criteria for hypoperfusion of such flaps. Methods: we performed vertical myocutaneous rectus abdominis flaps with upper pedicles bilaterally in 20 male Wistar rats, divided into two groups: with and without venous occlusion of the pedicle. We measured glucose levels in the flaps and in the systemic circulation with standard glucometers. We tested the accuracy of alternative diagnostic criteria for the detection of hypoperfusion. Results: from 15 minutes of venous occlusion on, there was a significant reduction in glucose levels measured in the congested flap (p<0.001). Using a minimum difference of 20mg/dl in the glycemic levels between the flap and systemic blood, 30 minutes after occlusion, as a diagnostic criterion, the sensitivity was 100% (95% CI 83.99-100%) and specificity of 90% (95% CI 69.90-97.21%) for the diagnosis of flap congestion. Conclusion: It is possible to measure glucose levels in vertical myocutaneous rectus abdominis flaps of Wistar rats, perfused or congested, using a common glucometer. The diagnostic criteria that compare the glucose levels in the flaps with the systemic ones were more accurate in the evaluation of tissue perfusion.

RESUMO Objetivo: validar um modelo experimental para mensuração de níveis glicêmicos em retalhos cirúrgicos com a utilização de glicosímetros comuns, e analisar os critérios diagnósticos para hipoperfusão destes retalhos. Métodos: foram realizados retalhos miocutâneos verticais de reto abdominal com pedículos superiores, bilateralmente, em 20 ratos Wistar machos, divididos em dois grupos: com e sem oclusão venosa do pedículo. Os níveis de glicose foram mensurados nos retalhos e na circulação sistêmica com glicosímetros comuns. A acurácia de critérios diagnósticos alternativos foi testada para a detecção de hipoperfusão. Resultados: a partir de 15 minutos de oclusão venosa, houve uma redução significativa dos níveis de glicose medidos no retalho congesto (p<0,001). Utilizando como critério diagnóstico uma diferença mínima de 20mg/dl nos níveis glicêmicos do retalho e do sangue sistêmico, 30 minutos após a oclusão, a sensibilidade foi de 100% (intervalo de confiança de 95% - 83,99 a 100%) e especificidade de 90% (intervalo de confiança de 95% - 69,90 a 97,21%) para o diagnóstico de congestão do retalho. Conclusão: os resultados demonstraram que é possível medir níveis de glicose em retalhos miocutâneos verticais de reto abdominal de ratos Wistar, perfundidos ou congestos, utilizando um glicosímetro comum. Os critérios diagnósticos que comparam os níveis de glicose nos retalhos com os níveis sistêmicos foram mais precisos na avaliação da perfusão tecidual.

Intra and postoperative evaluations of microcirculation and micro-rheological parameters in a rat model of musculocutaneous flap ischemia-reperfusion

PURPOSE:To examine how the ischemia-reperfusion injury of latissimus dorsi-cutaneous maximus (LDCM) musculocutaneous flap affects the microcirculatory (flap's skin surface) and hemorheological parameters, and whether an intraoperative deterioration would predictively suggest flap failure in the postoperative period.METHODS: Ten healthy male rats were subjected to the study. In Group I the left flap was sutured back after 2-hour, while the contralateral side was right after its elevation. In Group II the same technique was applied, but the pedicle of the left flap was atraumatically clamped for 2-hour. The contralateral side was left intact. On the flap skin surface laser Doppler tissue flowmetry measurements were done before and after and during the protocols applied in the groups. Microcirculatory and hemorheological examinations were done postoperatively.RESULTS: The microcirculatory parameters significantly decreased during immobilization and ischemia. Afterwards, all the regions showed normalization. In the retrospective analysis there was a prominent difference between the microcirculatory parameters of necrotic and survived flap during the early postoperative days (1-3) in Group II. Erythrocyte aggregation and deformability showed only slight differences.CONCLUSIONS: Two-hour ischemia and reperfusion caused deterioration in latissimus dorsi-cutaneous maximus flap microcirculation. Predicting the possible postoperative complication, the intraoperative laser Doppler measurement can be informative.