The use of telemedicine to maintain breast cancer follow-up and surveillance during the COVID-19 pandemic.

As a result from restricted economic activities and social distancing due to the coronavirus disease-2019 (COVID-19) pandemic, we observed a 49.4% decrease in outpatient appointments at our Institution. to minimize this impact on screening and oncological follow-up of breast cancer patients, telemedicine appointments were established. The authors demonstrate how a cancer center in the largest city in Brazil has managed outpatient appointments during the COVID-19 pandemic. This is a retrospective study of patients who had their appointments through telemedicine at the AC Camargo Cancer Center between June 2020 and October 2020, during the COVID-19 pandemic. Of the 77 patients who had telemedicine appointments, 36 (46.8%) accounted for breast cancer follow-up, 20 (26%) for breast cancer screening, 10 (13%) for benign breast disease evaluation, 7 (9%) for a second opinion, and 4 (5.2%) for general orientations. Routine surveillance/follow-up exams were requested for 45 (58.4%) patients and breast image exams and a request to return for a personal appointment for 30 (39%) patients. Two (2.6%) patients were requested to schedule a personal appointment immediately for a physical exam. In conclusion, telemedicine may be a feasible alternative to reduce personal outpatient appointments for cancer follow-up and breast cancer screening during the COVID-19 pandemic.

Neoadjuvant intraperitoneal chemotherapy followed by radical surgery and HIPEC in patients with very advanced gastric cancer and peritoneal metastases: report of an initial experience in a western single center.

BACKGROUND: The association of preoperative systemic and intraperitoneal chemotherapy has been described in Eastern patients with very good outcomes in treatment responders. The aim of this paper is to describe the initial results of this multidisciplinary regimen in gastric cancer patients with very advanced peritoneal metastases. CASE PRESENTATION: We present here the first four cases who received the treatment protocol. They had a baseline PCI between 19 and 33. Two patients had received systemic chemotherapy prior to this regimen. Three of them had significant response and were taken to cytoreductive surgery, while one patient who had 12 cycles of chemotherapy previously showed signs of disease progression and subsequently died. There was no significant postoperative morbidity, and three patients remain alive, two of them with no signs of recurrence. CONCLUSION: Systemic and intraperitoneal chemotherapy led to a marked response in peritoneal disease extent in our initial experience and allowed three of four patients with very advanced disease to be treated with cytoreductive surgery.

MRI features of breast cancer immunophenotypes with a focus on luminal estrogen receptor low positive invasive carcinomas.

To compare the magnetic resonance imaging (MRI) features of different immunophenotypes of breast carcinoma of no special type (NST), with special attention to estrogen receptor (ER)-low-positive breast cancer. This retrospective, single-centre, Institutional Review Board (IRB)-approved study included 398 patients with invasive breast carcinoma. Breast carcinomas were classified as ER-low-positive when there was ER staining in 1-10% of tumour cells. Pretreatment MRI was reviewed to assess the tumour imaging features according to the 5th edition of the Breast Imaging Reporting and Data System (BI-RADS) lexicon. Of the 398 cases, 50 (12.6%) were luminal A, 191 (48.0%) were luminal B, 26 (6.5%) were luminal ER-low positive, 64 (16.1%) were HER2-overexpressing, and 67 (16.8%) were triple negative. Correlation analysis between MRI features and tumour immunophenotype showed statistically significant differences in mass shape, margins, internal enhancement and the delayed phase of the kinetic curve. An oval or round shape and rim enhancement were most frequently observed in triple-negative and luminal ER-low-positive tumours. Spiculated margins were most common in luminal A and luminal B tumours. A persistent kinetic curve was more frequent in luminal A tumours, while a washout curve was more common in the triple-negative, HER2-overexpressing and luminal ER-low-positive immunophenotypes. Multinomial regression analysis showed that luminal ER-low-positive tumours had similar results to triple-negative tumours for almost all variables. Luminal ER-low-positive tumours present with similar MRI findings to triple-negative tumours, which suggests that MRI can play a fundamental role in adequate radiopathological correlation and therapeutic planning in these patients.

Myositis Ossificans of the Breast Mimicking Breast Cancer: A Case Report.

Myositis ossificans (MO) is an uncommon tumor characterized by a rapidly growing mass following a history of local trauma. Few cases of MO affecting the breast have been reported, and some were misdiagnosed as primary osteosarcoma of the breast or metaplastic breast carcinoma. The following case report presents a patient with a growing breast lump whose core biopsy result was suspicious for breast cancer. MO was diagnosed after analysis of the mastectomy specimen. This case highlights the importance of MO as a differential diagnosis of a growing soft-tissue mass after trauma to avoid unnecessary overtreatment. Keywords: Myositis Ossificans, Osteosarcoma, Breast Cancer, Mastectomy, Heterotopic Ossification © RSNA, 2023.

Diphencyprone as a therapeutic option in cutaneous metastasis of melanoma. A single-institution experience.

Diphencyprone has been reported as a local immunotherapy for cutaneous melanoma metastases. We aim to report cases of melanoma patients treated with diphencyprone in a single Brazilian institution and highlight their outcomes. Since 2012, we have treated 16 melanoma patients with cutaneous metastases with topical diphencyprone. To date, we have had 37.5% of complete response, 25% of partial responses, and 31.25% patients without any response. Treatment was well tolerated and local toxicity was easily controlled. We believe topical diphencyprone is a feasible treatment that can be another option for treating melanoma patients, especially in cases of in-transit or extensive disease.

Efficacy of ultrasound-guided fine-needle aspiration performed by surgeons newly trained in thyroid ultrasound.

BACKGROUND: There are a growing number of thyroid ultrasound courses to train endocrinologists, pathologists, and surgeons to perform ultrasound-guided fine-needle aspiration (FNA). However, there are limited data to support the efficacy of ultrasound-guided FNA performed by nonradiologists. METHODS: We compared the efficacy of ultrasound-guided FNA performed by surgeons newly trained in thyroid ultrasound with that of the same technique performed by 1 experienced radiologist. The ratio of nondiagnostic examinations was used to compare the 2 groups. RESULTS: A total of 197 ultrasound-guided FNAs were performed on 172 women (95.53%) and 8 men (4.47%) over a 12-month period. The efficacy of ultrasound-guided FNA did not differ between groups. A nondiagnostic report was found in 23% and 25.7% of the examinations performed by the radiologist and surgeons, respectively. CONCLUSION: The efficacy of ultrasound-guided FNAs performed by our 2 surgeons was similar to that of our radiologist. © 2016 Wiley Periodicals, Inc. Head Neck 39: 439-442, 2017.

Benefits of a standardized protocol for axillary management after neoadjuvant chemotherapy in a single center

Introduction: The axillary lymph node status is one of the most important prognostic factors in breast cancer. For locally advanced tumors, neoadjuvant chemotherapy favors higher rates of breast lumpectomy and downstaging tumor burden of axilla. The aim of this study was to evaluate the use of a standardized image-guided protocol after neoadjuvant chemotherapy to enable sentinel node dissection in patients with axillary downstaging, avoiding axillary dissection. Methods: Retrospective cohort study of data collected from medical records of patients who underwent neoadjuvant chemotherapy in a single center, from January 2014 to December 2018. The protocol comprises the placement of a metal clip in positive axillary lymph node, in patients with up to two clinically abnormal lymph nodes presented on imaging. After neoadjuvant chemotherapy, and once a radiologic complete response was achieved, sentinel node dissection was performed using blue dye and radiotracer. Axillary dissection were avoided in patients whose clipped sentinel node were negative for metastasis and in patients with three identified and negative sentinel node dissection. Results: A total of 471 patients were analyzed for this study: 303 before and 165 after the implementation of the protocol; 3 cases were excluded. The rate of sentinel node dissection in clinical nodes positive patients was statistically higher in this group when compared to patients treated before the protocol implementation (22.8% vs. 40.8%; p=0.001). Patients with triple negative and HER2-positive tumors underwent sentinel node dissection more frequently when compared to luminal tumors (p=0.03). After multivariate analysis, the variables that were associated with a greater chance of performing sentinel node dissection were clinical staging, type of surgery performed and implementation of the axillary assessment protocol. Conclusions: The results showed that the use of an easily and accessible image-guided protocol can improve sentinel node dissection in selected patients, even if the lymph node was positive previously to neoadjuvant treatment.

Partial laryngectomy in glottic cancer: complications and oncological results.

INTRODUCTION: Most patients with laryngeal carcinoma present tumors in the glottis that can be treated by different treatment modalities. Some authors consider open partial laryngectomy as obsolete, while others still deem this as a viable and cost-efficient option. OBJECTIVES: To compare the oncological and functional results of a series of patients undergoing partial laryngectomy vs. external radiotherapy for the treatment of glottic cancer. METHODS: Historical cohort study with a series of glottic carcinoma patients undergoing partial laryngectomy or external radiotherapy during a period of ten years. RESULTS: Sixty-two patients with glottic carcinoma were included. Group A comprised those submitted to partial laryngectomy (n=30), and Group B, those who underwent radiotherapy (n=32). They were homogeneous in the comparison of mean age, 56.4 vs. 60.4 years (p=0.12) and distribution in pathological stage (p=0.91). With regard to oncological outcome, there were no differences in distant metastasis rates, or second primary tumor between groups (p=1.0), as well as in disease-free time, laryngeal rescue-free time, and overall five-year survival. Severe complication rates were also similar between groups. CONCLUSION: Open partial laryngectomy had complication rates and oncological results similar to those of radiotherapy for patients with glottic carcinomas and should still be considered among the main available therapeutic options.

Postoperative complications following simultaneous therapeutic and contralateral prophylactic nipple-sparing mastectomy: a retrospective study

Introduction: Nipple-Sparing Mastectomy (NSM) is increasingly indicated for therapeutic and prophylactic purposes due to better cosmetic results with nipple maintenance. Postoperative complications have not been compared among patients who have undergone simultaneous therapeutic and contralateral prophylactic NSM. The aim of the present study was to evaluate the incidence and risk factors for postoperative complications in bilateral/unilateral NSMs, and therapeutic and/or prophylactic NSMs. Methods: Retrospective study of patients who underwent NSM between 2007 and 2017 at A.C. Camargo Cancer Center. Results: Among 290 patients, 367 NSMs were performed, 64 simultaneous therapeutic and contralateral prophylactic NSM. The latter were associated with more postoperative complications (OR=3.42; p=0.002), mainly skin flap necrosis (OR=3.79; p=0.004), hematoma (OR=7.1; p=0.002), wound infection (OR=3.45; p=0.012), and nipple-areola complex (NAC) loss (OR=9.63; p=0.003). Of the 367 NSMs, 213 were unilateral NSMs, which were associated with lower rates of postoperative complications (OR=0.44; p=0.003), especially skin flap necrosis (OR=0.32; p=0.001), hematoma (OR=0.29; p=0.008), wound infection (OR=0.22; p=0.0001), and reoperation (OR=0.38; p=0.008). Obesity was related to more postoperative complications (OR=2.55; p=0.01), mainly hematoma (OR=3.54; p=0.016), reoperation (OR=2.68; p=0.023), and NAC loss (OR=3.54; p=0.016). Patients' age (p=0.169), their smoking status (p=0.138), breast ptosis (0.189), previous chest radiotherapy (p 1), or previous breast surgery (p=0.338) were not related to higher chances of postoperative complications. Conclusions: Results suggest that performing therapeutic and contralateral prophylactic NSM as separated procedures may represent a good strategy for minimizing postoperative complications.

Pleomorphic adenoma of the breast

Pleomorphic adenoma (PA) is a common tumor of the salivary gland, but rarely occurs in the breast. PA of the breast is a benign tumor that usually presents as a periareolar nodule. Core-needle biopsies may yield misdiagnosis with complex fibroadenoma, phyllodes tumor and metaplastic breast cancer due to the mixture of stromal and epithelial elements. We present a case of PA of the breast suspected after core-needle biopsy, but confirmed after surgical excision. The importance to make a correct diagnosis consists in avoid extensive unnecessary surgery, such as mastectomy, since PA can be treated with local surgical resection.

Cowden Syndrome: a single institution case series and literature review / Síndrome de Cowden: serie de casos de una única institución y revisión de la literatura

OBJECTIVE: Cowden Syndrome belongs to a group of disorders that are associated with germline mutations in the tumor suppressor gene, phosphatase and tensin homolog (PTEN). The prevalence has been estimated to be 1 in 200,000-250,000. However, this prevalence may be underestimated due to many factors. Better understand Cowden Syndrome among our local population to provide genetic counseling and appropriate screening for different types of neoplasms associated to Cowden Syndrome. MATERIAL AND METHODS: Case series analysis based on data maintained by the Breast Cancer and Hereditary Cancer Departments of the AC Camargo Cancer Center, a large specialized hospital in Brazil. RESULTS: Five cases are presented according to their diagnostic criteria, cancer rates, and outcomes for Cowden Syndrome. CONCLUSION: These cases highlight the need for a multi-institutional evaluation of Cowden Syndrome cases in order to better comprehend its prevalence in Brazil. To improve the outcome of patients with CS, a greater understanding of this syndrome is needed, as well as recognition of the value of periodic screening

OBJETIVO: El síndrome de Cowden (SC) pertenece a un grupo de trastornos asociados a las mutaciones germinales en el gen supresor del tumor, homólogo de fosfatasa y tensina (PTEN). La prevalencia ha sido estimada en uno por cada 200.000-250.000 sujetos. Sin embargo, esta prevalencia puede subestimarse debido a muchos factores. Nuestro objetivo es hacer que nuestra población local comprenda mejor el SC para proporcionar asesoramiento genético, así como un cribado adecuado para los diferentes tipos de neoplasias asociadas a dicho síndrome. MATERIAL Y MÉTODOS: Análisis de una serie de casos basado en los datos mantenidos por los Departamentos de Cáncer de Mama y Cáncer Hereditario del Centro para el Cáncer AC Camargo, un gran hospital especializado de Brasil. RESULTADOS: Se presentan 5 casos con arreglo a sus criterios diagnósticos, tasas de cáncer y resultados para el SC. CONCLUSIÓN: Estos casos subrayan la necesidad de realizar una evaluación multi-institucional de los casos del SC, a fin de comprender mejor su prevalencia en Brasil. Para mejorar el resultado de los pacientes con SC se necesita una mayor comprensión del mismo, así como el reconocimiento del valor del cribado periódico

Accuracy of ultrasound-guided core-needle biopsy confronted with pathological findings and comparison of its costs with vacuum-assisted biopsy's costs

Introduction: Breast cancer screening has enhanced early­stage diagnosis by detection of impalpable tumors which require histopathological evaluation. Main percutaneous biopsy types are core-needle biopsy (CNB) and vacuum-assisted biopsy (VAB). CNB is less invasive and related to less bleeding and pain. VAB allows larger tissue samples and permits metal clip placement in biopsy bed for posterior localization in case of surgery. Access to VAB is restricted in Brazil due to its high costs. Objectives: To evaluate the agreement between pathological results of ultrasound (US) guided CNB with metal clip placement and surgery and settle false negative rates (FNR), sensibility, specificity, and accuracy of this method, for breast lesions < 20 mm. Methods: 388 US-guided CNB were retrospectively reviewed. Results: Surgical excision was performed in 317 patients. Overall FNR was 9.8%, (5.2% for lesions 10­20 mm), sensibility 90.2% (94.8% for lesions 10­20 mm), specificity 94.9% (94.1% for lesions 10­20 mm), and accuracy 91.1% (94.7% for lesions 10­20 mm). Cost of VAB varies from 2.2 to 12.5 times US-guided CNB. With metal clip placement, VAB costs 1.95 to 5.2 times US-guided CNB. Conclusions: For lesions that can be identified in US, CNB with metal clip placement has high sensitivity, specificity, and accuracy, as well as low FNR.

Breast implant-associated anaplastic large cell lymphoma in li-fraumeni syndrome: case-based literature review / Linfoma anaplásico de grandes células associado a implante na síndrome de Li-Fraumeni: relato de caso baseado em revisão de literatura

Breast implant-associated anaplastic large cell lymphoma is a rare disease related to chronic seroma around breast implants. Breast implant-associated anaplastic large cell lymphoma has been recently recognized by the World Health Organization as a type of T-cell non-Hodgkin lymphoma of the breast. The main features comprise chronic seroma which develops a year posterior to breast surgery, with symptoms such as breast pain, swelling, skin hyperemia and a nodule or mass of the breast. Li-Fraumeni Syndrome is associated with germline TP53 mutation and enhances the risks of developing many types of cancers, including breast and hematologic malignancies. We report a case of a 56-year-old female with Li-Fraumeni Syndrome and a history of breast cancer who underwent a mastectomy to treat breast cancer and prophylactic contralateral nipple-sparing mastectomy followed by bilateral breast implant reconstruction with textured silicone implants. This patient developed Breast implant-associated anaplastic large cell lymphoma seven years later. A literature review on multidisciplinary approach to this condition was performed.

O linfoma anaplásico de células grandes associado ao implante mamário é uma doença rara relacionada ao seroma crônico em torno dos implantes mamários. O linfoma anaplásico de células grandes associado ao implante foi recentemente reconhecido pela Organização Mundial de Saúde como um tipo de linfoma não-Hodgkin de células T da mama. As principais características incluem o seroma crônico que se desenvolve um ano depois da cirurgia da mama, com sintomas como dor na mama, inchaço, hiperemia da pele e um nódulo ou massa da mama. A síndrome de Li-Fraumeni está associada à mutação da linha germinativa no TP53 e aumenta o risco de desenvolvimento de muitos tipos de câncer, incluindo neoplasias mamárias e hematológicas. Relatamos um caso de uma mulher de 56 anos de idade com Síndrome de Li-Fraumeni e um histórico de câncer de mama submetido a uma mastectomia para tratar câncer de mama e mastectomia profilática contralateral poupadora de mamilo seguida de reconstrução bilateral de implantes mamários com implantes de silicone texturizados. Esta paciente desenvolveu linfoma anaplásico de células grandes associado ao implante mamário sete anos depois. Foi realizada uma revisão da literatura sobre uma abordagem multidisciplinar para essa condição.

Diphencyprone as a therapeutic option in cutaneous metastasis of melanoma. A single-institution experience

Abstract: Diphencyprone has been reported as a local immunotherapy for cutaneous melanoma metastases. We aim to report cases of melanoma patients treated with diphencyprone in a single Brazilian institution and highlight their outcomes. Since 2012, we have treated 16 melanoma patients with cutaneous metastases with topical diphencyprone. To date, we have had 37.5% of complete response, 25% of partial responses, and 31.25% patients without any response. Treatment was well tolerated and local toxicity was easily controlled. We believe topical diphencyprone is a feasible treatment that can be another option for treating melanoma patients, especially in cases of in-transit or extensive disease.

Partial laryngectomy in glottic cancer: complications and oncological results / Laringectomia parcial no câncer glótico: complicações e resultados oncológicos

ABSTRACT INTRODUCTION: Most patients with laryngeal carcinoma present tumors in the glottis that can be treated by different treatment modalities. Some authors consider open partial laryngectomy as obsolete, while others still deem this as a viable and cost-efficient option. OBJECTIVES: To compare the oncological and functional results of a series of patients undergoing partial laryngectomy vs. external radiotherapy for the treatment of glottic cancer. METHODS: Historical cohort study with a series of glottic carcinoma patients undergoing partial laryngectomy or external radiotherapy during a period of ten years. RESULTS: Sixty-two patients with glottic carcinoma were included. Group A comprised those submitted to partial laryngectomy (n = 30), and Group B, those who underwent radiotherapy (n = 32). They were homogeneous in the comparison of mean age, 56.4 vs. 60.4 years (p = 0.12) and distribution in pathological stage (p = 0.91). With regard to oncological outcome, there were no differences in distant metastasis rates, or second primary tumor between groups (p = 1.0), as well as in disease-free time, laryngeal rescue-free time, and overall five-year survival. Severe complication rates were also similar between groups. CONCLUSION: Open partial laryngectomy had complication rates and oncological results similar to those of radiotherapy for patients with glottic carcinomas and should still be considered among the main available therapeutic options.

Resumo Introdução: A maioria dos pacientes com carcinoma de laringe apresentam tumores na região glótica suscetíveis a diferentes modalidades de tratamento. Alguns autores consideram a laringectomia parcial aberta em desuso enquanto outros ainda a indicam como uma opção viável e custo eficiente. Objetivos: Comparar os resultados oncológicos e funcionais de uma série de pacientes submetidos à laringectomia parcial versus radioterapia externa para o tratamento do câncer glótico. Método: Estudo tipo coorte histórica com uma série de pacientes com carcinoma glótico submetidos à laringectomia parcial ou radioterapia externa em período de 10 anos. Resultados: Foram incluídos 62 pacientes com carcinoma glótico distribuídos em Grupo A: submetido à laringectomia parcial (n = 30) e Grupo B submetido a radioterapia (n = 32) que se mostraram homogêneos na comparação de média de idade de 56,4 vs. 60,4 (p = 0,12) e distribuição em estadios patológicos (p = 0,91). Com relação ao desfecho oncológico, não foram observadas diferenças nas taxas de metástase à distancia, ou segundo primário entre os grupos (p = 1,0) assim como no tempo livre de doença, tempo livre de resgate laríngeo e sobrevida geral em 5 anos. As taxas de complicações severas também foram semelhantes entre os grupos. Conclusão: A laringectomia parcial aberta apresentou taxas de complicações e resultados oncológicos semelhante àqueles do tratamento radioterápico para pacientes com carcinomas glóticos e ainda deve ser considera entre as principais opções terapêuticas disponíveis.

Chronic ω-3 fatty acids supplementation promotes beneficial effects on anxiety, cognitive and depressive-like behaviors in rats subjected to a restraint stress protocol.

Recent evidence has demonstrated dietary influence on the manifestation of different types of behaviors induced by stressor tasks. The present study examined the impact of ω-3 polyunsaturated fatty acids (PUFAs) supplementation in an early phase of the brain development with the goal of preventing or even attenuating the occurrence of stress-related behaviors such as depressive-like behaviors, anxiety and cognitive dysfunctions in male rats subjected to restraint stress. Our results indicated that the supplementation regimen successfully counteracted the anxiogenic effects of stress as evidenced by the rats' increased exploration time in the aversive arms of the elevated plus maze. The forced swimming test indicated that immobility and swimming were more deeply influenced by PUFAs supplementation, thereby demonstrating an antidepressant effect. Furthermore, cognitive function was shown to be intensely affected by restraint stress, but the effects were surprisingly counteracted by the PUFAs supplementation. Lastly, plasmatic corticosterone levels were demonstrated to be drastically increased by the restraint stress; however, PUFAs supplementation promoted a reduction of this stress-related hormone to levels that were comparable to those observed in the control group. Our results suggested that the mechanisms underlying these effects are possibly associated with the reduction of corticosterone levels promoted by the PUFAs supplementation in the stress-induced animals. Further studies to examine the participation of PUFAs in mediating different behaviors in rats subjected to restraint stress are warranted.

Estudo biomecânico da fixação pedicular curta na fratura-explosão toracolombar / Biomechanical evaluation of short-segment fixation for thoracolumbar burst-fractures / Estudio biomecánico de fijación pedicular corta en la fracturaexplosión toracolumbar

OBJETIVO: Comparar a rigidez biomecânica entre a coluna toracolombar intacta, a coluna com fratura explosão e a coluna com fratura explosão associada à fixação pedicular curta em suínos. MÉTODOS: 30 amostras de coluna toracolombar (T11-L3) de suínos foram divididas em três grupos com 10 amostras cada. O Grupo 1 representava a coluna intacta, o Grupo 2 representava a coluna com fratura explosão e o Grupo 3 a fratura explosão associada à fixação pedicular curta. Foi realizado o corte ósseo em "V" do terço médio do corpo vertebral comprometendo a coluna anterior e média de L1 para simular a fratura explosão. No Grupo 3 foi realizada a fixação pedicular com Pinos de Schanz. Os grupos foram submetidos ao teste biomecânico em compressão axial controlada. Os parâmetros de carga (N) e deslocamento (mm) eram gerados em um gráfico instantâneo e a rigidez (N/mm) foi determinada. O teste era interrompido quando ocorria uma queda súbita na curva no gráfico indicando falência da amostra. RESULTADOS: A rigidez das colunas fraturadas foi 53 por cento menor do que a rigidez das colunas intactas, sendo essa diferença estatisticamente significativa (p < 0,05). A fixação pedicular curta apresentou uma rigidez 50 por cento maior do que a coluna fraturada. Esse aumento foi estatisticamente significativo (p < 0,05). A rigidez da fixação pedicular curta foi 30 por cento menor do que a rigidez das colunas intactas. Essas diferenças foram estatisticamente significativas (p < 0,05). CONCLUSÃO: A fixação pedicular curta não é suficiente para restabelecer a rigidez da coluna intacta nos testes biomecânicos in vitro de compressão axial pura em modelos de fratura toracolombar de suínos.

OBJECTIVE: Compare the biomechanical stiffness between the intact spine, the spine with burst fracture and the short-segment pedicle fixation on porcine thoracolumbar burst fracture. METHODS: 30 samples of thoracolumbar spine (T11-L3) of porcine were divided into three groups with 10 samples each. Group 1 represented the intact spine, Group 2 the spine with burst fracture and Group 3 the burst fracture associated with short-segment pedicle fixation. The burst fracture injury was created with a "V" shape cut of the third middle of the vertebral body compromising the L1 anterior and medial columns simulating the burst fracture. Group 3 was stabilized with Schanz pedicle screws. The groups were subjected to biomechanical testing in a controlled axial compression. The parameters of load (N) and displacement (mm) were generated in a graphic snapshot and stiffness (N/mm) was determined. The test was stopped when there was a sudden drop in the curve on the chart indicating failure of the sample. RESULTS: The stiffness of the fractured spines was 53 percent lower than the stiffness of the intact spine and this difference was statistically significant (p < 0.05). The stiffness of the short-segment pedicle fixation was 50 percent higher than the fractured spine. This difference was statistically significant (p < 0.05). The stiffness of the short-segment pedicle fixation was 30 percent lower than the intact spine. These differences were statistically significant (p < 0.05). CONCLUSION: The short-segment pedicle fixation does not provide sufficient stability to restore the stiffness of the intact spine during pure axial load compression biomechanical testing.

OBJETIVO: Comparar la rigidez biomecánica entre la columna toracolumbar intacta, la columna con fractura-explosión y la columna con fractura-explosión asociada a la fijación pedicular corta en cerdos. MÉTODOS: 30 muestras de columna toracolumbar (T11-L3) de cerdos fueron divididas en tres grupos con 10 muestras cada una. El Grupo 1 representaba la columna intacta, el Grupo 2 representaba la columna con fractura-explosión y el Grupo 3 la fractura-explosión asociada a la fijación pedicular corta. Fue realizado el corte óseo en "V" del 1/3 medio del cuerpo vertebral, comprometiendo la columna anterior y media de L1, para simular la fractura-explosión. En el Grupo 3 fue realizada la fijación pedicular con pernos de Schanz. Los Grupos fueron sometidos al test biomecánico en compresión axial controlada. Los parámetros de carga (N) y desplazamiento (mm) eran generados en un gráfico instantáneo y la rigidez (N/mm) fue determinada. El test era interrumpido cuando ocurría una caída súbita en la curva en el gráfico señalando la falla de la muestra. RESULTADOS: La rigidez de las columnas fracturadas fue 53 por ciento menor que la rigidez de las columnas intactas, siendo esta diferencia estadísticamente significativa (p< 0,05). La fijación pedicular corta presentó una rigidez 50 por ciento mayor que la columna fracturada. Este aumento fue estadísticamente significativo (p<0,05). La rigidez de la fijación pedicular corta fue 30 por ciento menor que la rigidez de las columnas intactas. Estas diferencias fueron estadísticamente significativas (p<0,05). CONCLUSIÓN: La fijación pedicular corta no es suficiente para restablecer la rigidez de la columna intacta en las pruebas biomecánicas in vitro de compresión axial pura en modelos de fractura toracolumbar de cerdos.