Resultados oncológicos y factores pronósticos en pacientes con sarcoma sinovial tratados quirúrgicamente / Oncological outcomes and prognostic factors in surgically treated patients with synovial sarcoma

Resumen Introducción : El sarcoma sinovial es un tumor raro (incidencia de 1-3 casos por millón). Es más frecuente en adolescentes y adultos menores de 30 años. Se desarrolla en cualquier parte del cuerpo, siendo, las extremidades el lugar más frecuente de aparición (80% extremidades y 20% otras localizaciones: 8% tronco, retroperitoneal/ abdominal 7%, cabeza y cuello 5%). Los resultados on cológicos de los pacientes con sarcoma sinovial son disímiles. La tasa de supervivencia libre de recurrencia local, la supervivencia libre de eventos y la superviven cia global varían entre las series publicadas. Lo mismo sucede con los factores pronósticos de la enfermedad. Métodos : El objetivo fue analizar un grupo de 43 pacientes con diagnóstico de sarcoma sinovial de las extremidades tratados quirúrgicamente, y determinar (1) tasa de supervivencia global, (2) tasa de superviven cia libre de eventos, (3) tasa de recurrencia local y (4) factores de riesgo oncológicos. Resultados : La supervivencia global a los 2 años fue 90% (IC95%: 76-96%), y 67% (IC95%: 49-80%) a los 5 años. La supervivencia libre de eventos a los 2 años fue 68% (IC95% 51-80%) y a los 5 años 48% (IC95% 32-52%). El riesgo de recurrencia local a 2 años fue 9% (IC95% 3-25%) y a los 5 años 25% (IC95% 13-46%). Los factores de mal pronóstico oncológico fueron el grado histológico y la presencia de metástasis. Discusión : Podemos concluir que nuestros resulta dos oncológicos se asemejan a las series publicadas y que en nuestra serie hubo dos factores de mal pro nóstico.

Abstract Introduction : Synovial sarcoma is an unusual tumor with an incidence of 1-3 cases per million. It is more frequent in teenagers and young adults under 30. It develops anywhere, but the extremities are the most frequent place of appearance (80% extremities, 20% other locations: 8% trunk, 7% retroperitoneal/abdominal, 5% head and neck). Oncological results are different depending on the study. Survival rate free of local recur rence, survival rate free of events and global survival rate vary upon published studies. The same happens with the disease's prognostic factors. Methods : The objective was to analyze a group of 43 patients with diagnosis of synovial sarcoma of the extremities treated surgically and determine (1) global survival rate, (2) survival rate free of events, (3) local recurrence rate and (4) oncological risk factors. Results : The global survival rate at 2 years was 90% (IC95%: 76 - 96%) and 67% (IC95%: 49-80%) at 5 years. The survival rate free of events at 2 years was 68% (IC95% 51-80%) and 48% (IC95% 32-52%) at 5 years. The recurrence rate at 2 years was 9% (IC95% 3-25%) and 25% (IC95% 13-46%) at 5 years. The histological grade and metastatic presence were bad prognostic factors. Discussion : We can conclude that our oncological results are in line with those published in previous series and that there were two factors associated with poor prognosis.

[Oncological outcomes and prognostic factors in surgically treated patients with synovial sarcoma]. / Resultados oncológicos y factores pronósticos en pacientes con sarcoma sinovial tratados quirúrgicamente.

INTRODUCTION: Synovial sarcoma is an unusual tumor with an incidence of 1-3 cases per million. It is more frequent in teenagers and young adults under 30. It develops anywhere, but the extremities are the most frequent place of appearance (80% extremities, 20% other locations: 8% trunk, 7% retroperitoneal/abdominal, 5% head and neck). Oncological results are different depending on the study. Survival rate free of local recurrence, survival rate free of events and global survival rate vary upon published studies. The same happens with the disease's prognostic factors. METHODS: The objective was to analyze a group of 43 patients with diagnosis of synovial sarcoma of the extremities treated surgically and determine (1) global survival rate, (2) survival rate free of events, (3) local recurrence rate and (4) oncological risk factors. RESULTS: The global survival rate at 2 years was 90% (IC95%: 76 - 96%) and 67% (IC95%: 49-80%) at 5 years. The survival rate free of events at 2 years was 68% (IC95% 51-80%) and 48% (IC95% 32-52%) at 5 years. The recurrence rate at 2 years was 9% (IC95% 3-25%) and 25% (IC95% 13-46%) at 5 years. The histological grade and metastatic presence were bad prognostic factors. DISCUSSION: We can conclude that our oncological results are in line with those published in previous series and that there were two factors associated with poor prognosis.

Introducción: El sarcoma sinovial es un tumor raro (incidencia de 1-3 casos por millón). Es más frecuente en adolescentes y adultos menores de 30 años. Se desarrolla en cualquier parte del cuerpo, siendo, las extremidades el lugar más frecuente de aparición (80% extremidades y 20% otras localizaciones: 8% tronco, retroperitoneal/ abdominal 7%, cabeza y cuello 5%). Los resultados oncológicos de los pacientes con sarcoma sinovial son disímiles. La tasa de supervivencia libre de recurrencia local, la supervivencia libre de eventos y la supervivencia global varían entre las series publicadas. Lo mismo sucede con los factores pronósticos de la enfermedad. Métodos: El objetivo fue analizar un grupo de 43 pacientes con diagnóstico de sarcoma sinovial de las extremidades tratados quirúrgicamente, y determinar (1) tasa de supervivencia global, (2) tasa de supervivencia libre de eventos, (3) tasa de recurrencia local y (4) factores de riesgo oncológicos. Resultados: La supervivencia global a los 2 años fue 90% (IC95%: 76-96%), y 67% (IC95%: 49-80%) a los 5 años. La supervivencia libre de eventos a los 2 años fue 68% (IC95% 51-80%) y a los 5 años 48% (IC95% 32-52%). El riesgo de recurrencia local a 2 años fue 9% (IC95% 3-25%) y a los 5 años 25% (IC95% 13-46%). Los factores de mal pronóstico oncológico fueron el grado histológico y la presencia de metástasis. Discusión: Podemos concluir que nuestros resultados oncológicos se asemejan a las series publicadas y que en nuestra serie hubo dos factores de mal pronóstico.

Comportamiento del condrosarcoma óseo en pacientes menores de 40 años / Chondrosarcoma of bone in young patients

Resumen El condrosarcoma ocupa el segundo lugar en frecuencia, entre los tumores malignos primarios óseos, en pacientes adultos. Típicamente afecta a adultos de entre 40 y 70 años, siendo la mayoría de las series publicadas de este grupo etario. El objetivo de este estudio fue comunicar una serie de pacientes adultos jóvenes (16 a 40 años) con diagnóstico de condrosarcoma óseo, que buscó describir las particularida des en la forma de presentación en esta población. De un total de 37 pacientes de 16 a 40 años operados por condrosarcoma en nuestro centro, entre los años 2008 y 2019, 18 presentaron tumores de bajo grado (G1/tumor cartilaginoso atípico), 16 de grado intermedio (G2), quedando una minoría con tumores de alto grado (2 con condrosarcoma G3 y 1 con un condrosarcoma desdiferenciado). La tasa de supervivencia global fue del 97% (IC 95% 82%-99%) a 2 años y 90.5% (IC 95% 73%-96%) a 5 años y la tasa libre de recurrencia local fue de 92% (IC 95% 77%-97.5%) a los 12 meses y de 89% a los 2 y 5 años (IC 95% 73%-96%). El grado histológico fue el factor pronóstico más relevante. La concordancia del grado histológico entre el diagnóstico preoperatorio de la biopsia y el material de resección quirúrgica fue del 81% (30/37).

Abstract Chondrosarcoma is the second most frequent primary malignant bone tumor. It is typically described in adults between 40 and 70 years of age, being the majority of the series published in this age group. The objective of this study was to report a series of young adults (16-40 years old) with a diagnosis of chondrosarcoma of bone in order to describe the particularities of this tumor in this population. From a total of 37 patients between 16 and 40 years old, surgically treated for chondrosar coma in our institution, 18 had low-grade tumors (G1/atypical cartilaginous tumor), 16 had an intermediate-grade (G2), and a minority had high-grade tumors (2 with a G3 and 1 with a dedifferentiated chondrosarcoma). The overall survival rate was 97% (95% CI 82%-99%) at 2 years of follow-up and 90.5% (95% CI 73-96) at 5 years of follow-up. The local recurrence free rate was 92% (95% CI % 77%-97.5%) at 1 year of follow-up and 89% at 2 and 5 years of follow-up (95% CI 73%-96%). Histological grade was the most relevant prognostic factor. The concordance of the histological grade between the preoperative diagnosis of the biopsy and the surgical resection material was 81% (30/37).

[Chondrosarcoma of bone in young patients]. / Comportamiento del condrosarcoma óseo en pacientes menores de 40 años.

Chondrosarcoma is the second most frequent primary malignant bone tumor. It is typically described in adults between 40 and 70 years of age, being the majority of the series published in this age group. The objective of this study was to report a series of young adults (16-40 years old) with a diagnosis of chondrosarcoma of bone in order to describe the particularities of this tumor in this population. From a total of 37 patients between 16 and 40 years old, surgically treated for chondrosarcoma in our institution, 18 had low-grade tumors (G1/atypical cartilaginous tumor), 16 had an intermediate-grade (G2), and a minority had high-grade tumors (2 with a G3 and 1 with a dedifferentiated chondrosarcoma). The overall survival rate was 97% (95% CI 82%-99%) at 2 years of follow-up and 90.5% (95% CI 73-96) at 5 years of follow-up. The local recurrence free rate was 92% (95% CI % 77%-97.5%) at 1 year of follow-up and 89% at 2 and 5 years of follow-up (95% CI 73%-96%). Histological grade was the most relevant prognostic factor. The concordance of the histological grade between the preoperative diagnosis of the biopsy and the surgical resection material was 81% (30/37).

El condrosarcoma ocupa el segundo lugar en frecuencia, entre los tumores malignos primarios óseos, en pacientes adultos. Típicamente afecta a adultos de entre 40 y 70 años, siendo la mayoría de las series publicadas de este grupo etario. El objetivo de este estudio fue comunicar una serie de pacientes adultos jóvenes (16 a 40 años) con diagnóstico de condrosarcoma óseo, que buscó describir las particularidades en la forma de presentación en esta población. De un total de 37 pacientes de 16 a 40 años operados por condrosarcoma en nuestro centro, entre los años 2008 y 2019, 18 presentaron tumores de bajo grado (G1/tumor cartilaginoso atípico), 16 de grado intermedio (G2), quedando una minoría con tumores de alto grado (2 con condrosarcoma G3 y 1 con un condrosarcoma desdiferenciado). La tasa de supervivencia global fue del 97% (IC 95% 82%-99%) a 2 años y 90.5% (IC 95% 73%-96%) a 5 años y la tasa libre de recurrencia local fue de 92% (IC 95% 77%-97.5%) a los 12 meses y de 89% a los 2 y 5 años (IC 95% 73%-96%). El grado histológico fue el factor pronóstico más relevante. La concordancia del grado histológico entre el diagnóstico preoperatorio de la biopsia y el material de resección quirúrgica fue del 81% (30/37).

[Women's role in Orthopedic Training programs: What Proportion Do They Represent Today?] / Las mujeres y la residencia de ortopedia y traumatología en Argentina: ¿Qué proporción representan hoy?

Introduction: The objective of the study was to analyze all orthopedics residency programs of Argentina and determine:1)The proportion of females; 2) Social and demographics differences between genders: 3) The factors that influence positively or negatively in female decision to choose orthopedics. Method: An observational and descriptive study was carried out in two phases. First phase: analyze the database of the "Argentine Orthopedic Association during the period 2016-2017. Second phase: a survey was developed and sent to all the orthopedic residents focus on demographics, social and job preferences questions. Results and conclusion: A total of 933 residents were included for analysis. 121 (13%) were female and 812 (87%) were male. We got back 259 survey responses. We found statistically significant differences in terms of marriage or in union: female (16%) vs male (42 %) (p< 0.001); paternity (23.3%) vs maternity (4.5%) (p< 0.001). We observed that female mainly prefer pediatrics, foot and ankle and hand, while the primary choice of men is arthroplasty and arthroscopy. Focus on women analysis, the three main reasons that led them to choose the orthopedics residency program were: avidity for manual work (59%), personal desire (56%) and positive experience in orthopedics during the university (56%). The negative factors that influence female to choose an orthopedic training program are mainly related with the idea of physical demand and a male predominant work environment. In Argentina, women represent only 13% of all the orthopedics residents and this number is similar to other international reports.

Introducción: El objetivo del estudio fue analizar las residencias ortopedia y traumatología en Argentina y determinar: 1) La proporción de mujeres; 2) Diferencias sociales y demográficas entre géneros: 3) Los factores que influyen positiva o negativamente en las mujeres al elegir ortopedia. Métodos: Se realizó un estudio observacional y descriptivo en dos fases. Primera fase: se analizó la base de datos de la "Asociación Argentina de Ortopedia y Traumatología¨ durante el período 2016-2017. Segunda fase: se desarrolló una encuesta, enfocada en cuestiones demográficas, sociales y laborales, y se envió a todos los residentes de ortopedia. Resultados y conclusión: Se incluyeron 933 residentes,121 (13%) eran mujeres y 812 (87%) eran hombres. Recibimos 259 (28%) respuestas de la encuesta. En las características demográficas encontramos diferencias estadísticamente significativas en términos de matrimonio o convivencia: mujeres (16%) vs hombres (42%) (p <0,001); paternidad (23.3%) vs maternidad (4.5%) (p <0.001). Observamos que las mujeres prefieren principalmente ortopedia infantil, pie y el tobillo y mano, mientras que la elección primaria de los hombres es la artroplastia y la artroscopia. Focalizándonos en las mujeres, las tres razones principales para elegir esta residencia fueron: gusto por el trabajo manual (59%), deseo personal (56%) y experiencia positiva en ortopedia durante la universidad (56%). Dentro de los factores disuasivos se relacionan principalmente con la idea de la gran demanda física y un ambiente de trabajo predominantemente masculino. En Argentina, las mujeres representan solo el 13% de todos los residentes de ortopedia y este número es similar a otros informes internacionales.

[Denosumab as a treatment for giant cell tumor of bone. Indications, results and side effects]. / Denosumab como tratamiento neoadyuvante del tumor de células gigantes del hueso. Indicaciones, resultados y efectos adversos.

Giant cell tumor of bone is an intermediate, locally aggressive and rarely metastasizing, primary bone neoplasia. In recent years denosumab emerged as a treatment alternative for this pathology. The objective of this work was to analyze its indications as well as the clinical outcomes, side effects and local recurrence rates in patients diagnosed with giant cell tumor of bone, who received denosumab as neoadjuvant treatment. Between 2010 and 2018, 80 patients with giant cell tumor were analyzed, of whom 14 received denosumab as a neoadjuvant treatment. The minimum follow-up was 12 months. In 8 patients it was a primary tumor, while 6 showed tumor recurrence. In all cases, clinical improvement was evident. Thirteen patients presented radiographic changes, and 11 showed complete histological response. A local recurrence was evidenced in 6 of 14 patients, and at least one adverse effect related to denosumab (including tumor malignancy) was identified in 7. Despite being a useful tool for treating giant cell tumor, the use of denosumab is associated with a higher rate of local recurrences and is not free of adverse effects.

El tumor de células gigantes óseo es una neoplasia de agresividad local intermedia, que raramente metastatiza. En los últimos años el denosumab, anticuerpo monoclonal humano, surgió como una alternativa de tratamiento para esta enfermedad, al bloquear el comportamiento lítico tumoral. El objetivo de este trabajo fue determinar sus indicaciones y efectos adversos, analizando también los resultados oncológicos, y las tasas de recurrencia local en pacientes con diagnóstico de tumor de células gigantes óseo que recibieron denosumab como tratamiento neoadyuvante. Entre 2010 y 2018 se analizaron 80 pacientes con tumor de células gigantes, de los cuales 14 recibieron denosumab como tratamiento neoadyuvante. El seguimiento mínimo fue 12 meses. En 8 pacientes se trató de un tumor primario, mientras que 6 fueron pacientes con recidiva tumoral. En todos los casos se evidenció una mejoría clínica. Trece presentaron cambios radiográficos, y 11 respuesta histológica completa. En 6 de 14 pacientes se evidenció una recurrencia local y en 7 se identificó al menos un efecto adverso relacionado con el denosumab (incluyendo una malignización tumoral). A pesar de ser una herramienta útil para el tratamiento del tumor de células gigantes, el uso de denosumab está asociado a mayor tasa de recurrencias locales y no está exento de efectos adversos.

Denosumab como tratamiento neoadyuvante del tumor de células gigantes del hueso. Indicaciones, resultados y efectos adversos / Denosumab as a neoadjuvant treatment for giant cell tumor of bone. Indications, results and side effects

Resumen El tumor de células gigantes óseo es una neoplasia de agresividad local intermedia, que raramente metastatiza. En los últimos años el denosumab, anticuerpo monoclonal humano, surgió como una alternativa de tratamiento para esta enfermedad, al bloquear el comportamiento lítico tumoral. El objetivo de este trabajo fue determinar sus indicaciones y efectos adversos, analizando también los resultados oncológicos, y las tasas de recurrencia local en pacientes con diagnóstico de tumor de células gigantes óseo que recibieron denosumab como tratamiento neoadyuvante. Entre 2010 y 2018 se analizaron 80 pacientes con tumor de células gigantes, de los cuales 14 recibieron denosumab como tratamiento neoadyuvante. El seguimiento mínimo fue 12 meses. En 8 pacientes se trató de un tumor primario, mientras que 6 fueron pacientes con recidiva tumoral. En todos los casos se evidenció una mejoría clínica. Trece presentaron cambios radiográficos, y 11 respuesta histológica completa. En 6 de 14 pacientes se evidenció una recurrencia local y en 7 se identificó al menos un efecto adverso relacionado con el denosumab (incluyendo una malignización tumoral). A pesar de ser una herramienta útil para el tratamiento del tumor de células gigantes, el uso de denosumab está asociado a mayor tasa de recurrencias locales y no está exento de efectos adversos.

Abstract Giant cell tumor of bone is an intermediate, locally aggressive and rarely metastasiz ing, primary bone neoplasia. In recent years denosumab emerged as a treatment alternative for this pathology. The objective of this work was to analyze its indications as well as the clinical outcomes, side effects and local recurrence rates in patients diagnosed with giant cell tumor of bone, who received denosumab as neoadjuvant treatment. Between 2010 and 2018, 80 patients with giant cell tumor were analyzed, of whom 14 received deno sumab as a neoadjuvant treatment. The minimum follow-up was 12 months. In 8 patients it was a primary tumor, while 6 showed tumor recurrence. In all cases, clinical improvement was evident. Thirteen patients presented radiographic changes, and 11 showed complete histological response. A local recurrence was evidenced in 6 of 14 patients, and at least one adverse effect related to denosumab (including tumor malignancy) was identified in 7. Despite being a useful tool for treating giant cell tumor, the use of denosumab is associated with a higher rate of local recurrences and is not free of adverse effects.

[La Scientific activity in a highly complex center: What, who, where and how much is published?] / La actividad científica en un centro de alta complejidad: Qué, quién, dónde y cuánto se publica?

Introduction: We proposed to analyze the scientific production of our institution, through the publications indexed in the PUBMED and analyze: a) Total number of publications and progression over time; b) Type of publications; c) Unit participation; d) Relation between % publications / % medical unit staff; e) Impact factor. Methods: A retrospective research was performed in PUBMED database between 1/1/2013 and 12/31/2018 and all the papers that respond to the affiliation name of "Hospital Italiano" (spanish) o "Italian Hospital" (english) were reviewed. The following information was collected from each publication: authors, journal, impact factor, unit involved and language of publication. Results: A total of 1421 publications were included for the analysis. There was a progressive increase of 417% between 2013 and 2018. 802 (56%) were done only by our institution and 619 (44%) corresponded to multicenter studies. Internal medicine (341 - 23.99%) was the unit with more publications and Medical Informatics the unit with the best relation between % of publications and % professional staff (5.39). 82% (1167) of the papers were in English and the medina value of the impact factor was 2,61 (range: 0,01-29,78). Conclusion: The scientific production, measurable by the number of publications indexed in PUBMED has shown a progressive and sustained increase in time from 2013 to the present. We consider it important to stimulate and encourage professionals to continue with scientific production without neglecting quality standards of care activity.

Introducción: El objetivo del trabajo fue revisar la actividad científica de nuestra institución, a través de las publicaciones indexadas en PUBMED y analizar: a) Número total de publicaciones; b) Tipo de publicaciones; c) Servicios participantes; d) Relación % publicaciones / % plantel medico hospitalario; e) Factor de impacto de las revistas. Metodología: Se realizó una búsqueda retrospectiva en la base de datos PUBMED entre 2013 y 2018 inclusive y todos los artículos que tenían en su afiliación "Hospital Italiano" (español) o "Italian Hospital" (ingles)" fueron revisados. De cada publicación se recopilo: autores, revista, factor de impacto, servicio involucrado, instituciones intervinientes e idioma de publicación. Resultados: Un total de 1421 publicaciones fueron incluidas para el análisis y se evidencio un aumento progresivo del 417% entre 2013 y 2018. 802 (56%) correspondían a trabajos propios de nuestra institución y 619 (44%) a trabajos multicéntricos. El servicio de Clínica Médica (341 - 23.99%) fue el que presento más publicaciones e Informática Médica el de mejor relación entre % de publicaciones y % plantel profesional (5.39). El 82% (1167) de las publicaciones fueron realizadas en el idioma ingles y el valor medio del factor de impacto fue 2,61 (rango: 0,01-29,78). Conclusión: La producción científica, medible por el número de publicaciones indexadas en PUBMED ha mostrado un aumento progresivo y sostenido en el tiempo desde 2013 a la fecha. Consideramos importante estimular y fomentar a los profesionales para continuar con la actividad científica sin descuidar los estándares de calidad de la actividad asistencial.

Does Osteoarticular Allograft Reconstruction Achieve Long-term Survivorship after En Bloc Resection of Grade 3 Giant Cell Tumor of Bone?

BACKGROUND: En bloc resection of benign tumors is only indicated in aggressive lesions with substantial destruction of the affected bone. Few reports have evaluated the long-term outcome of Grade 3 giant cell tumor of bone (GCTB; defined as severe bone destruction and soft tissue extension) treated with en bloc resection and reconstruction with a massive allograft. We recently reported that patients with benign tumors achieved better allograft reconstruction survivorship compared with those treated for a malignant bone tumor. In light of that finding, we wondered whether osteoarticular allografts would be a viable long-term alternative for Grade 3 GCTB, which could be important in some countries because of greater availability and lower costs compared with endoprostheses. QUESTIONS/PURPOSES: We analyzed a group of patients with Grade 3 GCTBs treated with en bloc resection and osteoarticular allograft reconstruction in terms of (1) survivorship free from allograft removal at 10 years; (2) survivorship free from reoperation for any reason at 10 years, (3) functional results as measured by the Musculoskeletal Tumor Society (MSTS) score, (4) assessment of arthrosis at the knee. METHODS: We retrospectively analyzed all patients with a Grade 3 GCTB treated between 1980 and 2007. Only patients treated with en bloc resection and reconstruction with massive osteoarticular allografts were included in the analysis. The indication for osteoarticular reconstruction during that time included severe bone destruction with intraarticular compromise of the tumor, intraarticular fracture because of tumor growth, the presence of inadequate remaining subchondral bone to resist normal loading (for the distal femur or proximal tibia), and the preservation of a soft-tissue component (ligaments or meniscus) for articular stability. During the period, 75 patients were treated with en bloc resection. Patients treated with intralesional curettage (n = 7), reconstruction with an endoprosthesis (n = 2), intercalary arthrodesis (n = 13), or unicondylar reconstruction (n = 14) were excluded. Of the original 75 treated with en bloc resection, 52% (39) were treated with osteoarticular allograft reconstruction, and no patient was lost to follow-up before 2 years or had substantial missing data. However, of the 39 patients, another 21% (8) have not been seen in the last 5 years, but these were included here because they reached the 10-year minimum surveillance period before being lost. Twenty-three of those 39 patients were previously reported by our group and 16 new patients (treated between 1980-1985) were included in this series (eight distal radius, six distal femur, two proximal tibias), extending the follow-up period and including more patients for analysis. The median (range) follow-up duration was 26 years (10 to 34). We assessed survivorship using a Kaplan-Meier analysis, we drew MSTS scores retrospectively from patients´ medical records, and we graded arthrosis using the Ahlbäck scale for the knee (which was by far the most common joint involved, n = 31, and so it was the joint we assessed for the presence of arthrosis). RESULTS: The survivorship free from allograft removal was 85% at 10 years (95% CI 74 to 96). The allograft survivorship free from reoperation for any reason at 10 years was 72% (95% CI 59 to 87). The median (range) MSTS score was 28 points (19 to 30). The grade of arthrosis in the knee at last follow-up was analyzed in 20 patients and classified in nine as Ahlbäck Type 4, in six as Type 3, in three as Type 2 and in two as Type 5. CONCLUSIONS: Osteoarticular allograft reconstruction after a Grade 3 GCTB en bloc resection showed excellent long-term survivorship. We believe these results compare favorably with other studies on endoprosthetic reconstruction and head-to-head studies of these approaches should be performed; these would need to be multicenter trials. In the meantime, in locations where endoprostheses are unavailable or too expensive, we believe our results support the use of osteoarticular allografts. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Sarcomas de partes blandas en pacientes menores de 2 años. Serie de casos / Soft tissue sarcomas in infants. Case series

Los sarcomas de partes blandas en menores de 2 años son infrecuentes. Durante 2007-2017, 445 pacientes con sarcomas de partes blandas fueron tratados en nuestra Institución; 6 (el 0,5 %) eran menores de 2 años. Se analizaron los resultados clínicos y oncológicos en este grupo. La edad media de diagnóstico fue 15 meses. Cuatro eran varones y 2, mujeres. El seguimiento promedio fue 29 meses. El fibrosarcoma (n = 4) fue la variedad más frecuente. Cinco fueron tratados con cirugía de conservación del miembro; al restante se le realizó amputación. Todos realizaron tratamiento adyuvante con quimioterapia. La supervivencia a 24 meses fue del 100 %. Dos pacientes presentaron recidiva local; ambos casos, antes de los 24 meses.El tratamiento quirúrgico asociado a la quimioterapia impresiona ser la mejor opción terapéutica. La proporción de recurrencia local es alta para este grupo de pacientes luego de la cirugía de conservación del miembro.

Soft tissue sarcomas in children under 2 years of age are infrequent. During 2007-2017, a total of 445 patients diagnosed with soft tissue sarcomas were treated at our institution, 6 (0.5 %) were under 2 years. We analysed clinical and oncologic outcomes in this select group. The mean age of diagnosis was 15 months. Four patients were male and 2 female. The mean follow-up time was 29 months. Fibrosarcoma (n = 4) was the most frequent diagnosis. Five patients were treated with limb salvage surgery, and the remaining one had to undergo amputation. All patients received adjuvant treatment with chemotherapy. The 24-month survival rate was 100 %. Two patients presented a local recurrence before 24-months follow-up. Surgical treatment associated with chemotherapy seems to be the best therapeutic option. Local recurrence rate after limb salvage surgery is high for this group of patients

Soft tissue sarcomas in infants. Case series. / Sarcomas de partes blandas en pacientes menores de 2 años. Serie de casos.

Soft tissue sarcomas in children under 2 years of age are infrequent. During 2007-2017, a total of 445 patients diagnosed with soft tissue sarcomas were treated at our institution, 6(0.5%) were under 2 years. We analysed clinical and oncologic outcomes in this select group. The mean age of diagnosis was 15 months. Four patients were male and 2 female. The mean follow-up time was 29 months. Fibrosarcoma (n = 4) was the most frequent diagnosis. Five patients were treated with limb salvage surgery, and the remaining one had to undergo amputation. All patients received adjuvant treatment with chemotherapy. The 24-month survival rate was 100 %. Two patients presented a local recurrence before 24-months followup. Surgical treatment associated with chemotherapy seems to be the best therapeutic option. Local recurrence rate after limb salvage surgery is high for this group of patients.

Los sarcomas de partes blandas en menores de 2 años son infrecuentes. Durante 2007-2017, 445 pacientes con sarcomas de partes blandas fueron tratados en nuestra Institución; 6 (el 0,5 %) eran menores de 2 años. Se analizaron los resultados clínicos y oncológicos en este grupo. La edad media de diagnóstico fue 15 meses. Cuatro eran varones y 2, mujeres. El seguimiento promedio fue 29 meses. El fibrosarcoma (n = 4) fue la variedad más frecuente. Cinco fueron tratados con cirugía de conservación del miembro; al restante se le realizó amputación. Todos realizaron tratamiento adyuvante con quimioterapia. La supervivencia a 24 meses fue del 100 %. Dos pacientes presentaron recidiva local; ambos casos, antes de los 24 meses. El tratamiento quirúrgico asociado a la quimioterapia impresiona ser la mejor opción terapéutica. La proporción de recurrencia local es alta para este grupo de pacientes luego de la cirugía de conservación del miembro.

Do Massive Allograft Reconstructions for Tumors of the Femur and Tibia Survive 10 or More Years after Implantation?

BACKGROUND: Massive bone allografts have been used for limb salvage in patients undergoing bone tumor resections as an alternative to endoprostheses. Although several studies on massive allograft reconstructions for bone tumors reported that most complications occur in the first 3 years after surgery, there are no long-term reports on complications to substantiate this contention. We believe such information is important so that surgeons and patients can make more informed decisions when choosing a reconstructive method after tumor resection. QUESTIONS/PURPOSES: (1) What is the survival of allografts free from removal, amputation, or joint replacement in patients treated for bone tumors in the lower limb with a minimum of 10 years of followup? (2) What complications occur after 10 or more years of followup? (3) Are there factors associated with allograft survival, such as age, sex, the affected bone, reconstruction type (intercalary or osteoarticular allograft), tumor type (malignant or benign), failure type, and chemotherapy use? METHODS: We retrospectively analyzed the records of 398 patients treated in one center with benign or malignant bone tumors in the femur or tibia between 1986 and 2007. During the period in question, our general indications for using allografts (354 patients) included patients with benign or low-grade sarcomas and patients with high-grade sarcomas with clinical and imaging response to neoadjuvant chemotherapy. Other approaches such as endoprostheses (44 patients) were indicated if the patient received radiotherapy, in patients with high-grade sarcomas without clinical and imaging response to neoadjuvant chemotherapy, or with neurovascular tumor involvement. We excluded from the analysis 53 patients treated with allograft-prosthetic composites, 46 with hemicondylar osteoarticular allografts, and 57 with intercalary hemicylindrical allografts. The study was thus performed in 198 patients treated with segmental massive allografts in the long bones of the lower extremity (132 femurs and 66 tibias) after resection of a primary bone tumor, including 120 patients treated with osteoarticular and 78 with segmental intercalary allografts. A total of 32 (16%) of the 198 patients died before 10 years, and graft status was known in all of those patients; these patients were included (mean followup, 192 months; range, 1-370 months). All remaining 166 patients who were not known to have died before 10 years were accounted for at least 10 years after the allograft procedure (mean, 222 months; range, 120-370 months). No patient was lost to followup. The mean age was 22 years (range, 2-55 years); 105 patients were male (53%) and 93 were female. The predominant diagnoses were osteosarcoma (n = 125, 63%), giant cell tumor of bone (n = 27, 14%), and Ewing's sarcoma (n = 19, 10%). In all, 146 patients (74%) underwent chemotherapy. Selected variables were analyzed using multivariate logistic regression analyses to identify risk factors of allograft removal, joint replacement, or amputation. We performed competitive risk analysis with allograft removal, joint replacement, or amputation as the endpoint at 5, 10, and 20 years. Patient function was evaluated using the Musculoskeletal Tumor Society (MSTS)-93 scoring system. RESULTS: The risk of allograft removal, joint replacement, or amputation was 36% at 5 years (95% CI, 30-43), 40% at 10 years (95% CI, 33-47), and 44% at 20 years (95% CI, 37-51). Fractures occurred in 15% (29 patients), infection in 14% (27 patients), nonunion in 12% (23 patients) and tumor recurrence in 7% (13 patients). Thirty-two patients died of disease before 10 years; nine of these patients had a second surgery before death, eight had an amputation, and one underwent graft removal. Of the 166 patients who were still alive 10 years after the allograft procedure, 36 underwent allograft removal, six patients underwent joint replacement, and four had an amputation; however, after 10 years, six more allografts were removed (four due to fractures, one due to infection, and one due to instability), and another patient was amputated due to a second malignancy. After controlling for potentially confounding variables including death, we found that the risk of allograft removal, joint replacement, or amputation in osteoarticular tibial grafts (58% [95% CI, 43-73] at 5, 10, and 20 years) was higher than that of osteoarticular femur allografts (29% [95% CI, 18-39] at 5 years, 30% [95% CI, 19-40] at 10 years, 37% [95% CI, 25-48] at 20 years; p = 0.010) and tibia intercalary allografts (26% [95% CI, 7-45] at 5, 10 and 20 years; p = 0.020). Fractures occurred more frequently in the femur (18% [95% CI, 11-25]) than in the tibia (5% [95% CI, 0-10]; p < 0.010), and infections occurred more frequently in the tibia (24% [95% CI, 14-35]) than in the femur (4% [95% CI, 0-8]; p < 0.001). With the number of patients we had, we found no difference in the proportion of local recurrence in the tibia (12% [95% CI, 4-20]) compared with the femur (5% [95% CI, 1-9]; p < 0.053). CONCLUSIONS: Infections were the most common complications associated with allograft removal in the first 2 to 3 years after reconstruction and were more frequently associated with tibial allograft removal. Fractures were more commonly associated with graft removal with longer term followup and were more frequently associated with femoral allograft removal. Although we cannot directly compare our results with other types of reconstructions, we believe that allografts still have a role in the reconstruction of patients with a benign or low-grade bone tumor. Future studies in femoral allograft with longer followup should be performed to analyze factors that may explain why some grafts fail, such as the percent of the length of the bone resected, type and number of plates and screws used and type of fixation (rods versus plates). There was a higher incidence of graft removal in patients with proximal tibia osteoarticular allografts, which has led us to use this type of reconstruction only in pediatric patients over the last 15 years. LEVEL OF EVIDENCE: Level III, therapeutic study.

[Ewing sarcoma of the bone. Multidisciplinary approach and oncological results in 88 patients]. / Sarcoma de Ewing óseo. Enfoque multidisciplinario y resultados oncológicos en 88 pacientes.

Ewing sarcoma of the bone is a rare, highly aggressive tumor that typically affects children and young adults. In Argentina, the lack of Ewing's sarcoma registries reflects in the absence of information regarding prevalence, treatment protocols and patient's outcome. The purpose of this study was to analyze, in a group of patients diagnosed with Ewing sarcoma of the bone, treated with chemotherapy and limb-conserving surgery, their overall survival rate, local recurrence rate, and oncological risk factors. A retrospective research was conducted between 1990 and 2017. Eighty-eight patients with Ewing sarcoma of the bone matched the inclusion criteria. Median age was 14.5 years and median follow-up was 8.8 years. Overall survival rate was 79.5%, 69% and 64% at 2, 5 and 10 years respectively. Negative prognostic factors, associated with less survival rate after univariate analysis, were: bad response to chemotherapy (tumoral necrosis 0-89%), age > 16 years-old, central tumor localization and local recurrence. Gender and tumor size were not significant prognostic factors. After multivariate analysis, response to chemotherapy remained statistical significant. Local recurrence-free survival rate at 2 and 5 years was 87%. Tumor response to chemotherapy (0-89%) was the only significant factor for local recurrence. We consider that limb-salvage surgery, with neoadjuvant and adjuvant chemotherapy, are the mainstays of treatment for Ewing's sarcoma, with an overall survival rate, at 5 years, of 69%. In this population, response to chemotherapy is the most relevant prognostic factor, being associated with both local recurrence and overall survival.

El sarcoma de Ewing óseo es un tumor poco frecuente, agresivo, que afecta principalmente a niños y adultos jóvenes. Existe ausencia de registros en nuestro país respecto de la prevalencia de esta enfermedad, los esquemas de tratamiento utilizados y sus resultados. El objetivo fue analizar, en un grupo de pacientes con sarcoma de Ewing óseo tratados con quimioterapia y cirugía de conservación de miembro, las tasas de supervivencia global, de recurrencia local y los factores de riesgo oncológicos. Se incluyó a 88 pacientes. La edad media de la serie fue de 14.5 años y el seguimiento promedio de 8.8 años. La tasa de supervivencia global fue de 79.5% a los 2 años, de 69% a 5 años y de 64% a 10 años. Los factores pronósticos negativos asociados a menor supervivencia fueron: mala respuesta a la quimioterapia, edad > de 16 años, localización central, y recurrencia local. En el análisis multivariable únicamente la respuesta a la quimioterapia tuvo significancia estadística. La tasa libre de recurrencia local a 2 y 5 años fue del 87%. La mala respuesta a la quimioterapia fue el único factor significativo para la recurrencia local. Consideramos que la cirugía de conservación de miembro asociada a quimioterapia pre y postoperatoria debe ser el tratamiento para el sarcoma de Ewing óseo, alcanzando de esta manera una supervivencia global a 5 años del 69%. En nuestra serie, la respuesta a la quimioterapia ha sido el factor pronóstico más relevante para supervivencia y recurrencia local.

Sarcoma de Ewing óseo: Enfoque multidisciplinario y resultados oncológicos en 88 pacientes / Ewing sarcoma of the bone. Multidisciplinary approach and oncological results in 88 patients

El sarcoma de Ewing óseo es un tumor poco frecuente, agresivo, que afecta principalmente a niños y adultos jóvenes. Existe ausencia de registros en nuestro país respecto de la prevalencia de esta enfermedad, los esquemas de tratamiento utilizados y sus resultados. El objetivo fue analizar, en un grupo de pacientes con sarcoma de Ewing óseo tratados con quimioterapia y cirugía de conservación de miembro, las tasas de supervivencia global, de recurrencia local y los factores de riesgo oncológicos. Se incluyó a 88 pacientes. La edad media de la serie fue de 14.5 años y el seguimiento promedio de 8.8 años. La tasa de supervivencia global fue de 79.5% a los 2 años, de 69% a 5 años y de 64% a 10 años. Los factores pronósticos negativos asociados a menor supervivencia fueron: mala respuesta a la quimioterapia, edad ≥ de 16 años, localización central, y recurrencia local. En el análisis multivariable únicamente la respuesta a la quimioterapia tuvo significancia estadística. La tasa libre de recurrencia local a 2 y 5 años fue del 87%. La mala respuesta a la quimioterapia fue el único factor significativo para la recurrencia local. Consideramos que la cirugía de conservación de miembro asociada a quimioterapia pre y postoperatoria debe ser el tratamiento para el sarcoma de Ewing óseo, alcanzando de esta manera una supervivencia global a 5 años del 69%. En nuestra serie, la respuesta a la quimioterapia ha sido el factor pronóstico más relevante para supervivencia y recurrencia local.

Ewing sarcoma of the bone is a rare, highly aggressive tumor that typically affects children and young adults. In Argentina, the lack of Ewing's sarcoma registries reflects in the absence of information regarding prevalence, treatment protocols and patient´s outcome. The purpose of this study was to analyze, in a group of patients diagnosed with Ewing sarcoma of the bone, treated with chemotherapy and limb-conserving surgery, their overall survival rate, local recurrence rate, and oncological risk factors. A retrospective research was conducted between 1990 and 2017. Eighty-eight patients with Ewing sarcoma of the bone matched the inclusion criteria. Median age was 14.5 years and median follow-up was 8.8 years. Overall survival rate was 79.5%, 69% and 64% at 2, 5 and 10 years respectively. Negative prognostic factors, associated with less survival rate after univariate analysis, were: bad response to chemotherapy (tumoral necrosis 0-89%), age > 16 years-old, central tumor localization and local recurrence. Gender and tumor size were not significant prognostic factors. After multivariate analysis, response to chemotherapy remained statistical significant. Local recurrence-free survival rate at 2 and 5 years was 87%. Tumor response to chemotherapy (0-89%) was the only significant factor for local recurrence. We consider that limb-salvage surgery, with neoadjuvant and adjuvant chemotherapy, are the mainstays of treatment for Ewing's sarcoma, with an overall survival rate, at 5 years, of 69%. In this population, response to chemotherapy is the most relevant prognostic factor, being associated with both local recurrence and overall survival.

Face to Face Appointment vs. Telemedicine in First Time Appointment Orthopedic Oncology Patients: A Cost Analysis.

Medicine has evolved considerably in recent decades in part thanks to information and communication technologies in health (ICTs). However, face-to-face consultations continue to be the predominant model, since alternatives such as telemedicine are still the subject of debate. On the other hand, in some very specific specialties, centralization is relevant, mainly due to the low frequency and prevalence of diseases, as well as the need to have highly specialized professionals, causing problems in terms of accessibility and costs for the health system. In this study we have analyzed the first consultations to an orthopedics oncology service at a tertiary institution and performed an analysis of economic costs was carried out between 2 possible scenarios: face-to-face consultations versus telemedicine. Analyzing the 2 scenarios, there would be a cost-benefit in the use of telemedicine leading to a decrease in healthcare cost between 12.2% and 72%.

Is Navigation-guided En Bloc Resection Advantageous Compared With Intralesional Curettage for Locally Aggressive Bone Tumors?

BACKGROUND: The treatment of locally aggressive bone tumors is a balance between achieving local tumor control and surgical morbidity. Wide resection decreases the likelihood of local recurrence, although wide resection may result in more complications than would happen after curettage. Navigation-assisted surgery may allow more precise resection, perhaps making it possible to expand the procedure's indications and decrease the likelihood of recurrence; however, to our knowledge, comparative studies have not been performed. QUESTIONS/PURPOSES: The purpose of this study was to compare curettage plus phenol as a local adjuvant with navigation-guided en bloc resection in terms of (1) local recurrence; (2) nononcologic complications; and (3) function as measured by revised Musculoskeletal Tumor Society (MSTS) scores. METHODS: Patients with a metaphyseal and/or epiphyseal locally aggressive primary bone tumor treated by curettage and adjuvant therapy or en bloc resection assisted by navigation between 2010 and 2014 were considered for this retrospective study. Patients with a histologic diagnosis of a primary aggressive benign bone tumor or low-grade chondrosarcoma were included. During this time period, we treated 45 patients with curettage of whom 43 (95%) were available for followup at a minimum of 24 months (mean, 37 months; range, 24-61 months), and we treated 26 patients with navigation-guided en bloc resection, of whom all (100%) were available for study. During this period, we generally performed curettage with phenol when the lesion was in contact with subchondral bone. We treated tumors that were at least 5 mm from the subchondral bone, such that en bloc resection was considered possible with computer-assisted block resection. There were no differences in terms of age, gender, tumor type, or tumor location between the groups. Outcomes, including allograft healing, nonunion, tumor recurrence, fracture, hardware failure, infection, and revised MSTS score, were recorded. Bone consolidation was defined as complete periosteal and endosteal bridging visible between the allograft-host junctions in at least two different radiographic views and the absence of pain and instability in the union site. All study data were obtained from our longitudinally maintained oncology database. RESULTS: In the curettage group, two patients developed a local recurrence, and no local recurrences were recorded in patients treated with en bloc resection. All patients who underwent navigation-guided resection achieved tumor-free margins. Intraoperative navigation was performed successfully in all patients and there were no failures in registration. Postoperative complications did not differ between the groups: in patients undergoing curettage, 7% (three of 43) and in patients undergoing navigation, 4% (one of 26) had a complication. There was no difference in functional scores: mean MSTS score for patients undergoing curettage was 28 points (range, 27-30 points) and for patients undergoing navigation, 29 (range, 27-30 points; p = 0.10). CONCLUSIONS: In this small comparative series, navigation-assisted resection techniques allowed conservative en bloc resection of locally aggressive primary bone tumors with no local recurrence. Nevertheless, with the numbers available, we saw no difference between the groups in terms of local recurrence risk, complications, or function. Until or unless studies demonstrate an advantage to navigation-guided en bloc resection, we cannot recommend wide use of this novel technique because it adds surgical time and expense. LEVEL OF EVIDENCE: Level III, therapeutic study.

What Are the Complications of Allograft Reconstructions for Sarcoma Resection in Children Younger Than 10 Years at Long-term Followup?

BACKGROUND: Preservation of limb function after resection of malignant bone tumors in skeletally immature children is challenging. Resection of bone sarcomas and reconstruction with an allograft in patients younger than 10 years old is one reconstructive alternative. However, long-term studies analyzing late complications and limb length discrepancy at skeletal maturity are scarce; this information would be important, because growth potential is altered in these patients owing to the loss of one physis during tumor resection. QUESTIONS/PURPOSES: At a minimum followup of 10 years after reconstructions in children younger than 10 years of age at the time of reconstruction, we asked what is (1) the limb length discrepancy at skeletal maturity and how was it managed; (2) the risk of amputation; (3) the risk of allograft removal; and (4) the risk of second surgery resulting from complications? METHODS: Between 1994 and 2006, we performed 22 bone allografts after bone sarcoma resections in children younger than 10 years of age. Of those, none were lost to followup before the minimum followup of 10 years was reached, and an additional six had died of disease (of whom three died since our last report on this group of patients), leaving 16 patients whom we studied here. Followup on these patients was at a mean of 13.5 years (range, 10-22 years). During the period in question, no other treatments (such as extendible prostheses, amputations, etc) were used. The mean age at the time of the original surgery was 7 years (range, 2-10 years), and the mean age of the 16 alive patients at last followup was 20 years (range, 15-28 years). This series included 10 boys and six girls with 14 osteosarcomas and two Ewing sarcomas. Ten reconstructions were performed with an intercalary allograft and six with an osteoarticular allograft. The growth plate was uninvolved in three patients, whereas in the remaining 13, the growth plate was included in the resection (seven intercalary and six osteoarticular allografts). Limb length discrepancy at skeletal maturity was measured with full-length standing radiographs, and data were collected by retrospective study of a longitudinally maintained institutional database. The risk of amputation, allograft removal, and secondary surgery resulting from a complication was calculated by a competing-risk analysis method. RESULTS: We observed no limb length discrepancy at skeletal maturity in the three patients with intercalary resections in whom we preserved the physes on both sides of the joint (two femurs and one tibia); however, one patient developed malalignment that was treated with corrective osteotomy of the tibia. The remaining 13 patients developed limb length discrepancy as a result of loss of one physis. Seven patients (four femurs, two tibias, and one humerus) developed shortening of ≤ 3 cm (mean, 2.4 cm; range, 1-3 cm) and no lengthening was performed. Six patients developed > 3 cm of limb discrepancy at skeletal maturity (all distal femoral reconstructions). In four patients this was treated with femoral lengthening, whereas two declined this procedure (each with 6 cm of shortening). In the four patients who had a lengthening procedure, one patient had a final discrepancy of 4 cm, whereas the other three had equal limb lengths at followup. The risk of amputation was 4% (95% confidence interval [CI], 0-15) and none occurred since our previous report. The risk of allograft removal was 15% (95% CI, 1-29) and none occurred since our previous report on this group of patients. The risk of other operations resulting from a complication was 38% (95% CI, 19-57). Eleven patients underwent a second operation resulting from a complication (three local recurrences, five fractures, one infection, one nonunion, and one tibial deformity), of which three were performed since our last report on this group of patients. CONCLUSIONS: Limb length inequalities and subsequent procedures to correct them were common in this small series of very young patients as were complications resulting in operative procedures, but overall most allografts remained in place at long-term followup. In skeletally immature children, bone allograft is one alternative among several that are available (such as rotationplasty and endoprosthesis), and future studies with long followup may be able to compare the available options with one another. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Virtual Planning and Allograft Preparation Guided by Navigation for Reconstructive Oncologic Surgery: A Technical Report.

INTRODUCTION: Advanced virtual simulators can be used to accurately detect the best allograft according to size and shape. STEP 1 ACQUISITION OF MEDICAL IMAGES: Obtain a multislice CT scan and a magnetic resonance imaging (MRI) scan preoperatively for each patient; however, if the time between the scans and the surgery is >1 month, consider repeating the MRI because the size of the tumor may have changed during that time. STEP 2 SELECT AN ALLOGRAFT USING VIRTUAL IMAGING TO OPTIMIZE SIZE MATCHING: Load DICOM images into a virtual simulation station (Windows 7 Service Pack 1, 64 bit, Intel Core i5/i7 or equivalent) and use mediCAS planning software ( medicas3d.com ) or equivalent (Materialise Mimics or Amira software [FEI]) for image segmentation and virtual simulation with STL (stereolithography) files. STEP 3 PLAN AND OUTLINE THE TUMOR MARGINS ON THE PREOPERATIVE IMAGING: Determine and outline the tumor margin on manually fused CT and MRI studies using the registration tool of the mediCAS planning software or equivalent (Materialise Mimics software.). STEP 4 PLAN AND OUTLINE THE SAME OSTEOTOMIES ON THE ALLOGRAFT: Determine and outline the osteotomies between host and donor using the registration tool of the mediCAS planning software or equivalent (Materialise Mimics software.). STEP 5 ASSESS THE PATIENT AND ALLOGRAFT IN A VIRTUAL SCENARIO: Be sure to consider the disintegration of bone tissue that occurs during the osteotomy and corresponds to the thickness of the blade (approximately 1.5 mm). STEP 6 NAVIGATION SETTINGS: A tool of the mediCAS planning software allows the virtual preoperative planning (STL files) to be transferred to the surgical navigation format, DICOM files. STEP 7 PATIENT AND ALLOGRAFT INTRAOPERATIVE NAVIGATION: The tumor and allograft are resected using the navigated guidelines, which were previously planned with the virtual platform. RESULTS: The 3D virtual preoperative planning and surgical navigation software are tools designed to increase the accuracy of bone tumor resection and allograft reconstruction3.