Radioterapia en colgajos peroneos. Revisión de la densidad ósea en colgajos peroneos irradiados frente a no irradiados / Radiotherapy in fibular flaps. Review of bone density and complications after radiotherapy

INTRODUCCIÓN: El colgajo peroneo es actualmente una de las técnicas más elegidas para la reconstrucción de defectos mandibulares. Muchos de los pacientes reconstruidos con este colgajo presentan patología oncológica que precisa tratamiento adyuvante con radioterapia. Los efectos adversos de la radioterapia sobre los tejidos son conocidos, pudiendo desembocar en osteorradionecrosis. El objetivo de este estudio es el análisis de la densidad ósea de los colgajos peroneos en los pacientes que han recibido radioterapia frente a los que no, y su posible correlación con las complicaciones posteriores. MATERIAL Y MÉTODOS: Realizamos un estudio retrospectivo de los colgajos peroneos realizados por nuestro servicio desde enero de 2011 hasta diciembre de 2016. Los criterios de inclusión de los pacientes fue el haber sido reconstruidos con un colgajo peroneo y disponer de un TC de control a los tres meses postradioterapia en caso de haberla precisado. Se recogió la edad, densidad ósea peronea, desviación estándar cuerpo mandibular remanente y colgajo peroneo, así como las complicaciones postoperatorias. Los datos extraídos fueron analizados a través del Software SAS (Statistical Analisys System). RESULTADOS: En total se recogieron 61 pacientes, siendo la media de edad de 54,46 años. De estos 61 pacientes se excluyeron 11 al no presentar TC de control, de los 50 pacientes restantes, 27 recibieron tratamiento radioterápico adyuvante (54 %) mientras 23 no la recibieron (46 %). En los pacientes irradiados un alto porcentaje (84,62 %) recibieron altas dosis de radioterapia (> 60 Gy). Se encontraron diferencias estadísticamente significativas (p < 0,05) respecto a la edad y la desviación estándar de la densidad ósea del cuerpo mandibular remanente, mientras que en el resto de los parámetros no se encontraron diferencias estadísticamente significativas. Los pacientes irradiados presentaron un mayor porcentaje de complicaciones frente a los pacientes no irradiados sin diferencias estadísticamente significativas. DISCUSIÓN Las nuevas técnicas de radioterapia de intensidad modulada permiten una dosis relativamente uniforme en un objetivo, evitando altas dosis en los tejidos circuncidantes. A pesar del avance en las técnicas de radioterapia, actualmente en la mayoría de centros se continúa realizando un tratamiento completo del volumen del lecho tumoral, que incluye en el campo de irradiación el colgajo con el que se reconstruye. Los casos de osteonecrosis mandibular que se presentaron fueron en pacientes irradiados y a nivel del cuerpo mandibular remanente. La densidad ósea a nivel del colgajo peroneo sí que presentó diferencias estadísticamente significativas en pacientes irradiados frente a no irradiados; este aspecto puede influir en el índice de complicaciones. CONCLUSIONES: Consideramos con los resultados del estudio, plantear nuevos estudios prospectivos para valorar la necesidad de irradiar el tejido óseo del colgajo peroneo como parte del volumen del lecho tumoral, siendo que este tejido no ha estado en contacto con el tumor primario, ante el mayor índice de complicaciones asociados a la radioterapia en estos tejidos

INTRODUCTION: The fibular flap is currently one of the most chosen techniques for the reconstruction of mandibular defects. Many of the patients reconstructed with this flap present oncological pathology that requires adjuvant treatment with radiotherapy. The adverse effects of radiotherapy on tissues are known, and can lead to Osteorradionecrosis. The aim of this study is to analyze the bone density of peroneal flaps in patients who have received radiotherapy against those who do not and their possible correlation with subsequent complications. MATERIAL AND METHODS: We designed a retrospective study of the fibular flaps performed by our service from January 2011 to December 2016. The criteria for inclusion of patients was to have been reconstructed with a peroneal flap and have a control CT at 3 months after radiotherapy. Age, bone density, standard deviation and further complications were extracted. The extracted data was analyzed through the SAS (statistical Analisys System) Software. RESULTS: 61 patients were collected; the mean age was of 54.46 years. Of these 61 patients were excluded 11 by not presenting control TC, of the 50 patients remaining, 27 received adjuvant radiotherapy treatment (54 %) while 23 did not receive (46 %). In irradiated patients a high percentage (84.62 %) received high doses of radiotherapy (> 60 Gy). Statistically significant differences were found (p < 0.05) with respect to age and standard deviation of bone density of the remaining mandibular body, while in the rest of the parameters no statistical significant differences were found. Irradiated patients presented a higher percentage of complications compared to non-irradiated patients without statistically significant differences. DISCUSSION: The new techniques of intensity-modulated radiotherapy allow a relatively uniform dose in a target, avoiding high doses in the circumcising tissues. Despite the progress in radiotherapy techniques, currently in most centers, it continues to perform a complete treatment of the volume of the tumor bed that includes in the field of irradiation the flap with which it is reconstructed. The cases of mandibular osteonecrosis that were presented were in irradiated patients and in the remaining mandible. Bone density at the level of the fibular flap showed statistically significant differences in irradiated patients compared to non-irradiated, this aspect may influence in the index of complications. CONCLUSIONS: We consider to propose new prospective studies to assess the need to irradiate the bone tissue of the fibular flap as part of the volume of the tumor bed, knowing that this tissue has not been in contact with the primary tumor, and the high index of complications associated with radiotherapy

Comparative osteoradionecrosis rates in bony reconstructions for head and neck malignancy.

BACKGROUND: Bony free flaps are used to reconstruct head and neck cancer defects. The most commonly used flaps are the free fibula flap and the deep circumflex iliac artery (DCIA) flap. Radiotherapy may be given post-operatively to prevent cancer recurrence. This radiotherapy can, however, destroy the bone; a complication termed osteoradionecrosis (ORN). Although there have been studies comparing free fibula and DCIA flaps in terms of success rates and complications, few have assessed the incidence of ORN in both groups. METHODS: A retrospective cohort study was conducted involving patients from Royal Melbourne Hospital and St Vincent's Hospital Melbourne who had either a free fibula or DCIA flap for head and neck cancer reconstruction in the past 10 years. Data collected included demographic, operative, and postoperative data. Analysis was performed using Statistical Package for Social Sciences and Microsoft Excel, utilising t-tests, chi-square tests and logistic regression analyses. RESULTS: A total of 154 patients were identified. Of these patients, 127 had free fibula flaps and 27 had free DCIA flaps. Twelve patients had ORN post-op, 10 had free fibula flaps, and 2 had free DCIA flaps. No statistically significant difference was found between the ORN rates in free fibula flaps and free DCIA flaps. CONCLUSION: Rates of ORN incidence should not be a major consideration in preoperative planning of free flaps for mandibular reconstruction as both fibula and DCIA free flaps are comparable.

Low-intensity pulsed ultrasound increases blood vessel size during fracture healing in patients with a delayed-union of the osteotomized fibula.

Disturbed vascularity leads to impaired fracture healing. Since low-intensity pulsed ultrasound (LIPUS) increases new bone formation in delayed-unions, we investigated whether LIPUS increases blood supply in delayed-unions of the osteotomized fibula, and if LIPUS-increased bone formation is correlated to increased blood supply. Blood vessel parameters were analysed using histology, immunohistochemistry, and histomorphometric analysis as well as their correlation with bone formation and resorption parameters. Fibular biopsies of thirteen patients with a delayed-union of the osteotomized fibula treated for 2-4 months with or without LIPUS originating from a randomized prospective double-blind placebo-controlled clinical trial were studied. In histological sections of the fibular biopsies parameters of blood vessel formation were measured and were related to histomorphometric bone characteristics of newly formed bone of the same samples analysed in our previously published study on the effects of LIPUS on bone healing at the tissue level in delayed-unions. LIPUS-treated delayed-unions and sham-treated delayed-unions as well as healed delayed-unions and failed-to-heal delayed-unions were compared. The volume density of blood vessels was increased in LIPUS-treated delayed-unions compared to sham-treated controls. LIPUS did not change blood vessel number, but significantly increased blood vessel size. Healed delayed-unions as well as LIPUS-treated and sham-treated delayed-unions showed significant correlations between blood vessel size and osteoid volume. LIPUS increases blood vessel size, essential for fracture healing, in bone from patients with a delayed-union of the osteotomized fibula. The increased osteoid volume in delayed-unions can largely be explained by increased blood supply and perfusion.

Stimulation of neo-angiogenesis by combined use of irradiated and vascularized living bone graft for oncological reconstruction.

Reconstruction for large bone and osteochondral defects following musculoskeletal tumor excision remains challenging. Mega-prosthesis is clearly a useful reconstructive tool. Because the survival time of tumor patients has been increasing due to better treatment options, the aim of our group is to achieve complete biological reconstruction without using any artificial materials. With this approach, durability would not be a limitation. In the present study, we reviewed the biological reconstructive procedures currently available for large bone defects after tumor excision. Devitalized bone autograft is particularly well suited in the region where allografts are not readily available. However, the complication rate, such as infection and spontaneous bone resorption, was unexpectedly high due to non-viable graft. In an attempt to reduce these complications, we have used irradiated bone autograft in combination with free vascularized viable bone graft. In an experimental study, we demonstrated a neo-vascularization effect of vascularized bone graft with devitalized bone autograft, i.e. to convert dead bone into living bone. Clinically, this technique is best indicated for reconstruction of intercalary bone defect, especially tibial shaft. Some degree of articular change occurs after irradiation and cannot be prevented, even with the combined use of vascularized bone graft. In our experience, secondary procedures such as surface replacement prosthesis are necessary to treat the osteoarthritis in such cases, even if the radiological finding is severe. The rationale for a combined vascularized and irradiated bone autograft is the cumulative advantage provided by the biological properties of the former with the mechanical endurance of the latter.

A new syndrome of microtia with mixed type hearing loss, renal agenesis, and multiple skeletal anomalies.

We report on a 17-year-old man who presented with unreported combination of right sided microtia and preauricular skin tag with conductive hearing loss, unilateral renal agenesis, partial syndactyly of forth and fifth metacarpals, multiple tarsal coalitions, absent toe, and hypoplastic tibia and fibula. Radiological and clinical findings did not match with the previously described syndromes with the type of anomalies seen in the case. We propose that this represents a new syndrome.

Effects of irradiation on the appositional and longitudinal growth of the tibia and fibula of the rat with and without radioprotectant.

The effect of therapeutic levels of irradiation on appositional bone growth was compared with its effect on longitudinal growth in the skeletally immature rat model. The widths and lengths of the tibiae and fibulae of young rats were studied at 2, 4, 6, and 12 weeks after exposure to 17.5 Gy x-irradiation to the knee region of the right leg, with and without the aminothiol radioprotectant amifostine 20 minutes before radiation. Irradiation retarded growth in the width of the tibia to a greater extent (19%-27%) than longitudinal growth (9%-21%). The appositional growth discrepancy decreased over time, whereas the length discrepancy increased. The proximal fibula, in contrast, undergoes a normal decrease in width over time, and irradiation retarded this contraction by 14%. Appositional growth does not appear to be spared from the damaging effects of irradiation, but a catch-up phenomenon is observed that is not seen in longitudinal growth. Amifostine reduced the radiation-induced loss in tibial width by 40% to 50% and in length by 12% to 30%.