New and safe experimental model of radiation-induced neurovascular histological changes for microsurgical research.

The aim is to create a new and safe experimental model of radiation-induced neurovascular histological changes with reduced morbidity and mortality for use with experimental microsurgical techniques. Seventy-two Sprague-Dawley rats (250-300 g) were divided as follows: Group I: control group, 24 rats clinically evaluated during six weeks; Group II: evaluation of acute side-effects (two-week follow-up period), 24 irradiated (20 Gy) rats; and Group III: evaluation of subacute side-effects (six-week follow-up period), 24 irradiated (20 Gy) rats. Variables included clinical assessments, weight, vascular permeability (arterial and venous), mortality and histological studies. No significant differences were observed between groups with respect to the variables studied. Significant differences were observed between groups I vs II-III regarding survival rates and histological changes to arteries, veins and nerves. Rat body weights showed progressive increases in all groups, and the mortality rate of the present model is 10.4% compared with 30-40% in the previous models. In conclusion, the designed model induces selective changes by radiotherapy in the neurovascular bundle without histological changes affecting the surrounding tissues. This model allows therapeutic experimental studies to be conducted, including the viability of microvascular and microneural sutures post radiotherapy in the cervical neurovascular bundle.

Effect of Previous Irradiation on Vascular Thrombosis of Microsurgical Anastomosis: A Preclinical Study in Rats.

BACKGROUND: The objective of the present investigation was to compare the effect of neoadjuvant irradiation on the microvascular anastomosis in cervical bundle using an experimental model in rats. METHODS: One hundred forty male Sprague-Dawley rats were allocated into 4 groups: group I, control, arterial microanastomosis; group II, control, venous microanastomosis; group III, arterial microanastomosis with previous irradiation (20 Gy); and group IV, venous microanastomosis with previous irradiation (20 Gy). Clinical parameters, technical values of anastomosis, patency, and histopathological parameters were evaluated. RESULTS: Irradiated groups (III and IV) and vein anastomosis groups (II and IV) showed significantly increased technical difficulties. Group IV showed significantly reduced patency rates (7/35) when compared with the control group (0/35). Radiotherapy significantly decreased the patency rates of the vein (7/35) when compared with the artery (1/35). Groups III and IV showed significantly reduced number of endothelial cells and also showed the presence of intimal thickening and adventitial fibrosis as compared with the control group. CONCLUSION: Neoadjuvant radiotherapy reduces the viability of the venous anastomosis in a preclinical rat model with a significant increase in the incidence of vein thrombosis.

Bernese Periacetabular Osteotomy in a Young Adult with an Ipsilateral Renal Transplant: A Case Report.

CASE: An eighteen-year-old woman was referred to our center because of left groin pain and was diagnosed with acetabular dysplasia. The proposed treatment was a Bernese periacetabular osteotomy (PAO). The patient had undergone two renal transplants due to polycystic kidney disease; the current, functional kidney was at the lateral inguinal fossa on the left side. The patient was on chronic immunosuppressants and antihypertensive therapy. CONCLUSION: The present case shows that PAO can be a safe procedure with good outcomes even in patients who have undergone renal transplantation.

Effect of administration of platelet-rich plasma in early phases of distraction osteogenesis: an experimental study in an ovine femur model.

BACKGROUND: It has been suggested that platelet-rich plasma (PRP) might enhance bone formation. The aim of this study was to quantify the effect of PRP administered in the early phases of distraction osteogenesis in an ovine femur model. METHODS: Twenty sheep aged 4 months underwent osteotomy of the femoral diaphysis followed by distraction osteogenesis. The sheep were divided into two groups of 10. One group received three injections of PRP on days 0, 10, and 20 of the procedure (PRP group) and the other received no additional treatment (control group). The results were evaluated by computed tomography (CT) and histology on completion of distraction osteogenesis (day 40). CT evaluation included measurement of the callus and bone density. Femur size was also measured proximally and distally. Histological evaluation was used to quantify osteoblasts, osteoclasts, vascular lumens, and trabecular maturity by zones and to calculate trabecular bone, fibrous tissue, and cartilage ratios. RESULTS: Radiological and histological evaluation of the regenerate bone showed no significant differences between the PRP group and the control group for any of the variables analysed. The only significant difference detected was a wider femur (increased diaphyseal thickness) at the proximal and distal levels in the PRP group. CONCLUSION: We found no radiological or histological evidence that the administration of PRP in the early phases of distraction osteogenesis enhances bone formation.

Solitary osteochondroma: spontaneous regression.

Osteochondromas are the most common benign bone tumours. Nevertheless, their origin and biological behaviour are poorly understood. Rarely, spontaneous regression of osteochondromas may occur. We report the case of a 9-year-old girl with a solitary osteochondroma of the femur that regressed almost completely within 4 years, a fact that should be taken into account when deciding the management of these lesions, especially in young children.

Synovial hemangioma in the knee of a 10-month-old boy.

Synovial hemangioma is a benign vascular tumor. While mainly affecting the knee, it can also appear in other joints or tissues. The condition is very rare in children. A delay between debut and diagnosis due to its unspecific symptomatology is common. We report a case of a boy affected by an intra-articular synovial hemangioma of the knee with a debut at the early age of 10 months, the youngest reported in English literature.