Osteoid osteoma is a tumour of bone characterised by pain which is relieved by aspirin and nonsteroidal anti-inflammatory drugs. Very high levels of prostaglandins have been found in the lesion. In five patients with osteoid osteoma, prostaglandin E2 (PGE2) and prostacyclin (PGI2) synthesis in the nidus yielded 1155.6 +/- 496.5 (mean +/- SD) and 245.2 +/- 89.8 pg/mg respectively, values which are 33 and 26 times higher than in fragments of normal bone. The sclerotic bone around the nidus produced both prostaglandins at the same rate as normal bone. In three patients the excretion rate of the major urinary metabolite of systemic PGI1 was reduced to 50% one month after removal of the tumour. The urinary excretion rate of 6-keto-PGF1 alpha, reflecting intrarenal PGI2 synthesis, was not changed after operation. These results offer new insight into the pain mechanism in osteoid osteoma.

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The aim of the study is to analyze and report the results of the surgical activity in a spinal unit of a trauma hub in central Italy during COVID-19 pandemic. Surgical activity was compared between COVID 19 pandemic and the same period of time in 2019 at our institution. A 50% reduction of surgical procedures during the last three months was observed compared with the same period of time in 2019. The compliance with the containment rules for the spread of the infection, were sufficient to allow safe surgical activity for the medical teams and patients.

Originally aimed at treating degenerative syndromes of the lumbar spine, percutaneous minimally invasive posterior fixation is nowadays even more frequently used to treat some thoracolumbar fractures. According to the modern principles of saving segment of motion, a short implant (one level above and one level below the injured vertebra) is generally used to stabilise the injured spine. Although the authors generally use a short percutaneous fixation in treating thoracolumbar fractures with good results, they observed some cases in which the high fragmentation of the vertebral body and the presence of other associated diseases (co-morbidities) did not recommend the use of a short construct. The authors identified nine cases, in which a long implant (two levels above and two levels below the injured vertebra) was performed by a percutaneous minimally invasive approach. Seven patients (five males/two females) were affected by thoracolumbar fractures. T12 vertebra was involved in three cases, L1 in two cases, T10 and L2 in one case, respectively. Two fractures were classified as type A 3.1, two as A 3.2, two as A 3.3 and one as B 2.3, according to Magerl. In the present series, there were also two patients affected by a severe osteolysis of the spine (T9 and T12) due to tumoral localisation. All patients operated on with long instrumentation had a good outcome with prompt and uneventful clinical recovery. At the 1-year follow-up, all patients except one, who died 11 months after the operation, did not show any radiologic signs of mobilisation or failure of the implant. Based on the results of the present series, the long percutaneous fixation seems to represent an effective and safe system to treat particular cases of vertebral lesions. In conclusion, the authors believe that a long implant might be an alternative surgical method compared to more aggressive or demanding procedures, which in a few patients could represent an overtreatment.