Comportamiento biológico de mallas para la reparación de paredes abdominales. Resultados preliminares en un modelo animal / Biological behavior of meshes used for abdominal wall surgery. Preliminary results in an animal model

Resumen La falla en la reparación de los defectos de la pared abdominal se relaciona con una alteración en la integración del material protésico. El objetivo de este trabajo fue evaluar el comportamiento biológico de mallas utilizadas en cirugía de paredes abdominales en un modelo animal. Luego de la confección de un defecto parietal se colocó una malla intraperitoneal, utilizando 4 grupos de 10 ratas; 1) Prolene (polipropileno microporo de alto peso), 2) Ultrapro (polipropileno + poliglecaprone, macroporo de bajo peso), 3) Proceed (polipropileno + polidoxanona + celulosa oxidada regenerada, macroporo de peso intermedio), y 4) Physiomesh (polipropileno + poliglecaprone, macroporo de bajo peso). Se realizó análisis macroscópico y microscópico a los 30 días y los resultados fueron evaluados por dos observadores independientes. Al examen macroscópico, la integración de la prótesis fue > 75% en todos los grupos. El análisis microscópico mostró mayor inflamación global y número de células gigantes multinucleadas en Prolene (p < 0.01) y menor cantidad de células inflamatorias en la interface músculo-malla en Physiomesh < Ultrapro (p < 0.05). La organización de las fibras de colágeno fue similar para todas las mallas, aunque hubo mayor depósito de colágeno en los espacios inter-filamento para las mallas macroporosas (p < 0.01). Concluimos que las mallas de polipropileno microporo y alto peso producen mayor reacción inflamatoria y de cuerpo extraño. Por lo tanto, las mallas compuestas tendrían una mejor biocompatibilidad y serían mejor toleradas por el huésped.

Abstract An adequate integration of the prosthetic materials used to repair abdominal wall defects is necessary for satisfactory outcomes. We aimed to evaluate, in an animal model, the biological behavior of meshes used for abdominal wall surgery. Four groups of 10 rats were separated. After laparotomy, intraperitoneal prostheses were placed: 1) Prolene (polypropylene microporous, heavy-weight), 2) Ultrapro (polypropylene + poliglecaprone, macroporous low-weight), 3) Proceed (polypropylene + polidoxanone + regenerated oxidized cellulose, microporous medium-weight), 4) Physiomesh (polypropylene + poliglecaprone, macroporous lowweight). Macroscopic and microscopic analyses were performed at 30 days. The results were evaluated by two independent observers and expressed in means with standard deviation. For statistical analysis p < 0.05 was considered significant. On macroscopic examination, mesh integration was greater than 75% in all cases. Microscopic analysis showed greater global inflammation and more multinucleated giant cells in Prolene (p < 0.01). Less inflammatory cells were observed at the muscle-mesh interface in Physiomesh vs. Ultrapro (p < 0.05). Collagen fibers disposition was similar in all meshes, although, microporous meshes had higher collagen deposit in the interfilamentous spaces (p < 0.01). In conclusion, in our animal model, microporous and heavy-weight polypropylene meshes produce greater inflammatory and foreign body reaction. Thus, composite meshes would have greater biocompatibility and better tolerance by the host.

[Biological behavior of meshes used for abdominal wall surgery. Preliminary results in an animal model]. / Comportamiento biológico de mallas para la reparación de paredes abdominales. Resultados preliminares en un modelo animal.

An adequate integration of the prosthetic materials used to repair abdominal wall defects is necessary for satisfactory outcomes. We aimed to evaluate, in an animal model, the biological behavior of meshes used for abdominal wall surgery. Four groups of 10 rats were separated. After laparotomy, intraperitoneal prostheses were placed: 1) Prolene® (polypropylene microporous, heavy-weight), 2) Ultrapro® (polypropylene + poliglecaprone, macroporous low-weight), 3) Proceed® (polypropylene + polidoxanone + regenerated oxidized cellulose, microporous medium-weight), 4) Physiomesh® (polypropylene + poliglecaprone, macroporous lowweight). Macroscopic and microscopic analyses were performed at 30 days. The results were evaluated by two independent observers and expressed in means with standard deviation. For statistical analysis p < 0.05 was considered significant. On macroscopic examination, mesh integration was greater than 75% in all cases. Microscopic analysis showed greater global inflammation and more multinucleated giant cells in Prolene® (p < 0.01). Less inflammatory cells were observed at the muscle-mesh interface in Physiomesh® vs. Ultrapro® (p < 0.05). Collagen fibers disposition was similar in all meshes, although, microporous meshes had higher collagen deposit in the interfilamentous spaces (p < 0.01). In conclusion, in our animal model, microporous and heavy-weight polypropylene meshes produce greater inflammatory and foreign body reaction. Thus, composite meshes would have greater biocompatibility and better tolerance by the host.

La falla en la reparación de los defectos de la pared abdominal se relaciona con una alteración en la integración del material protésico. El objetivo de este trabajo fue evaluar el comportamiento biológico de mallas utilizadas en cirugía de paredes abdominales en un modelo animal. Luego de la confección de un defecto parietal se colocó una malla intraperitoneal, utilizando 4 grupos de 10 ratas; 1) Prolene® (polipropileno microporo de alto peso), 2) Ultrapro® (polipropileno + poliglecaprone, macroporo de bajo peso), 3) Proceed® (polipropileno + polidoxanona + celulosa oxidada regenerada, macroporo de peso intermedio), y 4) Physiomesh® (polipropileno + poliglecaprone, macroporo de bajo peso). Se realizó análisis macroscópico y microscópico a los 30 días y los resultados fueron evaluados por dos observadores independientes. Al examen macroscópico, la integración de la prótesis fue > 75% en todos los grupos. El análisis microscópico mostró mayor inflamación global y número de células gigantes multinucleadas en Prolene® (p < 0.01) y menor cantidad de células inflamatorias en la interface músculo-malla en Physiomesh® < Ultrapro® (p < 0.05). La organización de las fibras de colágeno fue similar para todas las mallas, aunque hubo mayor depósito de colágeno en los espacios inter-filamento para las mallas macroporosas (p < 0.01). Concluimos que las mallas de polipropileno microporo y alto peso producen mayor reacción inflamatoria y de cuerpo extraño. Por lo tanto, las mallas compuestas tendrían una mejor biocompatibilidad y serían mejor toleradas por el huésped.

[Primary orbital squamous cell carcinoma]. / Carcinoma escamoso primario de órbita.

Primary orbital squamous cell carcinoma is a rare entity. There is little published literature. We report a case of primary squamous cell carcinoma of the orbital soft tissues. Surgical resection offered the best treatment for the patient. Complete resection of the lesion was achieved. The patient received adjuvant radiotherapy due to the proximity of the lesion to the surgical margins. Surgical treatment is feasible and should be considered as part of the surgeon's arsenal. However, therapeutic decisions must be made on a case-by-case basis.

Carcinoma escamoso primario de órbita / Primary orbital squamous cell carcinoma

El carcinoma escamoso primario de órbita es una entidad poco frecuente. Hay escasa literatura publicada al respecto. Presentamos un caso de carcinoma escamoso primario de los tejidos blandos de la órbita. La resección quirúrgica ofrecía el mejor tratamiento para esta paciente. Se realizó un abordaje cráneo-facial y se logró la resección completa de la lesión. La paciente recibió radioterapia adyuvante debido a la proximidad de la lesión a los márgenes quirúrgicos. El tratamiento quirúrgico es factible y debe ser considerado como parte del arsenal del cirujano. Sin embargo, las decisiones terapéuticas deben tomarse teniendo en cuenta las particularidades de cada caso.

Primary orbital squamous cell carcinoma is a rare entity. There is little published literature. We report a case of primary squamous cell carcinoma of the orbital soft tissues. Surgical resection offered the best treatment for the patient. Complete resection of the lesion was achieved. The patient received adjuvant radiotherapy due to the proximity of the lesion to the surgical margins. Surgical treatment is feasible and should be considered as part of the surgeon´s arsenal. However, therapeutic decisions must be made on a case-by-case basis.

Could an abdominal drainage be avoided in complicated acute appendicitis? Lessons learned after 1300 laparoscopic appendectomies.

INTRODUCTION: Complicated appendicitis (CA) may be a risk factor for postoperative intra-abdominal abscess formation (IAA). In addition, several publications have shown an increased risk of postoperative collection after laparoscopic appendectomy. Most surgeons prefer to place a drain to collect contaminated abdominal fluid to prevent consequent abscess formation. We aimed to evaluate the utility of placing an intra-abdominal drain in laparoscopic appendectomy for complicated acute appendicitis. MATERIAL AND METHODS: From January 2005 to June 2015 all charts of consecutive patients who underwent laparoscopic appendectomy for CA were revised. CA was defined as a perforated appendix with associated peritonitis. The sample was divided into two groups, G1: intra-abdominal drain and G2: no drain. Demographics, operative factors and 30-day postoperative complications were analyzed. RESULTS: In the study period 1300 laparoscopic appendectomies were performed. Laparoscopic findings showed that 17.3% of the surgeries were for complicated acute appendicitis (225 patients). Fifty-six patients (25%) were in G1 and 169 patients (75%) in G2. No significant differences in clinical presentation and demographics were found (p: NS). G1 had an increased conversion rate (G1: 19.6% vs. G2: 7.1%; p: 0.007). No differences were found in the overall morbidity (G1: 32.1% vs. G2: 21.3%, p: NS). The rate of postoperative IAA was 14.2% in G1 and 8.9% in G2 (p: NS). Length of stay was higher in G1 (G1: 5.2 days vs. G2 2.9 days, p: 0.001). There was no mortality in either group. CONCLUSION: The placement of intra-abdominal drain in complicated acute appendicitis may not present benefits and may even lengthen hospital stay. These observations suggest that there is no need of using a drain in laparoscopic appendectomy for complicated acute appendicitis.

[Giant adrenal myelolipoma. Right laparoscopic adrenalectomy]. / Mielolipoma adrenal gigante. Adrenalectomía derecha laparoscópica.

Adrenal myelolipoma is a rare, benign, non-functioning tumor. It is composed by fat and hematopoietic tissues. We present the case of a 33-year-old woman with diagnosis of a 14 cm diameter non-functioning right adrenal incidentaloma, with imaging features suggestive of myelolipoma. Based on the benign nature of the tumor, laparoscopic resection was performed. Histopathology showed a myelolipoma, weighting 444 grams. The patient evolved with an uneventful postoperative period. Laparoscopic adrenalectomy for a giant myelolipoma was feasible and successful.

Mielolipoma adrenal gigante: Adrenalectomía derecha laparoscópica / Giant adrenal myelolipoma. Right laparoscopic adrenalectomy

El mielolipoma es un tumor adrenal poco frecuente. Se trata de un tumor benigno no funcionante compuesto por tejido adiposo y hematopoyético. Presentamos el caso de una paciente de 33 años de edad con diagnóstico de incidentaloma adrenal de 14 cm de diámetro no funcionante. Los estudios imagenológicos presentaban características sugestivas de mielolipoma. Debido a la naturaleza benigna del tumor se decidió el abordaje laparoscópico. La anatomía patológica informó un mielolipoma de 444 gramos. La paciente evolucionó favorablemente en el postoperatorio. El abordaje laparoscópico para la resección del mielolipoma gigante fue factible y exitoso.

Adrenal myelolipoma is a rare, benign, non-functioning tumor. It is composed by fat and hematopoietic tissues. We present the case of a 33-year-old woman with diagnosis of a 14 cm diameter non-functioning right adrenal incidentaloma, with imaging features suggestive of myelolipoma. Based on the benign nature of the tumor, laparoscopic resection was performed. Histopathology showed a myelolipoma, weighting 444 grams. The patient evolved with an uneventful postoperative period. Laparoscopic adrenalectomy for a giant myelolipoma was feasible and successful.

[Melanoma behavior according to age]. / Comportamiento del melanoma según la edad.

In recent years the incidence of melanoma in elderly patients has increased with an unfavorable oncologic outcome due not only to immune deterioration but also to greater aggressiveness of the tumor. The aim of this study was to evaluate the behavior of cutaneous melanoma in relation to age. A consecutive series of cases with melanoma operated in a reference center in the period 2001-2013 was included. The sample was divided into two groups according to the age. Group 1 (G1): under 65 years and Group 2 (G2): over 65 years. Histopathological variables and oncologic outcomes were compared between the two groups. Three hundred and eighty eight patients were operated. They belonged to G1 241 (62%) and to G2 147 (38%). Both groups were homogeneous with respect to the histological type of melanoma. Group 2 had thicker melanomas (Breslow > 4 mm 19% vs. 7%, p < 0.005) and higher rates of ulceration (37% vs. 20%, p: 0.007) and distant metastases (stage IV 11% vs. 3%, p 0.01). There was no difference between groups regarding nodal involvement. With a mean follow up of 45 (6-98) months throughout the series, recurrence of disease was higher in group 2 (26% vs. 17%, p: 0.03), but the specific mortality showed no significant difference (9.5% vs. 5.3%, p: 0.12). In conclusion, cutaneous melanoma in patients over 65 years is more aggressive with higher rates of local recurrence and distant metastases.

Predictores de metástasis de ganglio centinela en melanoma cutáneo / Predictors for sentinel lymph node metastasis of cutaneous melanoma

Antecedentes: se han descripto múltiples factores de riesgo para el compromiso del ganglio centinela en melanoma cutáneo, pero existe discrepancia en cuanto a la importancia de cada uno de ellos. El objetivo de este estudio fue identificar factores predictores de metástasis del ganglio centinela en pacientes con melanoma cutáneo. Material y métodos: se incluyeron los mapeos linfáticos realizados en pacientes con melanoma cutáneo entre 2001 y 2013. Se evaluaron variables demográficas y características del tumor primario. Se realizaron análisis univariado y multivariado en busca de factores predictivos del compromiso del ganglio centinela. Resultados: en el período citado se efectuaron 117 mapeos linfáticos; 25 pacientes (21,3%) presentaron ganglio centinela positivo. La edad y la localización de la lesión primaria no se asociaron con riesgo de metástasis linfática. Los melanomas con espesor de 1 a 4 mm se asociaron con mayor compromiso ganglionar que aquellos con espesor menor de 1 mm, y aquellos con espesor mayor de 4 mm tuvieron aún mayor tasa de ganglio centinela positivo. La presencia de ulceración y el tipo histológico nodular tuvieron mayor compromiso del ganglio centinela. La regresión tumoral y el número de mitosis no se relacionaron con la positividad del ganglio centinela. En el análisis multivariado solo el índice de Bres-low mayor de 4 mm y el tipo histológico nodular presentaron significación estadística. Conclusiones: la ulceración, el índice de Breslow y el tipo histológico nodular se asocian a mayor compromiso del ganglio centinela. El índice de Breslow y el tipo histológico nodular serían predictores independientes de compromiso ganglionar en melanoma cutáneo.

Background: multiple risk factors have been described in order to predict sentinel lymph node (SLN) compromise in patents with cutaneous melanoma. However, there is no agreement as to the impor-tance of each of those factors. The aim of this study was to identify risk factors of SLN metastasis. Methods: consecutive SLN biopsies in patents with cutaneous melanoma in the period 2001-2013 were included. Demographic factors and primary tumor characteristics were evaluated and univariate and multivariate analyses were performed. Results: of 117 SLN biopsies, 25 patents (21.3%) had a positive SLN. Age and tumor locaton were not associated with risk of lymphatic metastasis. Patents with Breslow thickness 1-4 mm were associated with more nodal involvement than those with thickness < 1mm and those with > 4mm had even higher rate of positive SLN. Ulceraton and nodular histology showed higher SLN compromise. Tumor regres-sion and number of mitoses were not associated with positive SLN. In the multivariate analysis Breslow thickness > 4mm and nodular histologic type showed statstical significance. Conclusions: ulceraton, Breslow thickness and nodular histologic type are associated with the SLN status. Furthermore, Breslow thickness and nodular histologic type could be independent predictor factors of SLN involvement.