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Study Type Retrospective cohort. Introduction The treatment of rare neoplastic conditions is challenging, especially because studies providing high levels of evidence are often lacking. Such is the case with primary tumors of the spine (PTS), which have a

OBJECTIVE: Even though carbon ions treatment (CIRT) of sacral chordoma (SC) substantially reduces tumor mass, tumor remnants are observed in most patients. Differentiating tumor remnants from necrosis is challenging, expensive in terms of imaging and time-consuming. So far, there has not been a systematic histological and metabolic analysis of post-CIRT lesions. We designed a prospective study aiming to histologically a metabolically differentiate between viable tumor and foci of necrosis and of fibrosclerosis after CIRT and correlate these findings to clinical outcome in patients with SC. PATIENTS AND METHODS: Between January 2013 and December 2016 18 patients, 12 males and 6 females, with histological confirmation of sacral chordoma, underwent CIRT. The total dose was 70.4 GyE, with a daily fraction of 4.4 GyE, for 4 weeks. MRI was performed every three months after treatment. FDG PET-CT scan and CT-guided needle biopsy were performed 6-12 months after CIRT. The incidence of complications (intraoperative and postoperative), local control (LC), overall survival (OS) and progression-free survival (PFS), changes in neurological status, clinical outcomes and toxicity were considered. RESULTS: All histological analysis but 2 reported signs of necrosis and of fibrosclerosis after CIRT. One of these 2 patients turned into a dedifferentiated chordoma. Radiological partial response (PR) was observed in 10 patients (56.3%) and stable disease (SD) in 5 patients (28.3). Two patients (11%) had a local relapse. The overall survival rate was 100% at 24 months. FDG PET CT after CIRT showed uptake decreasing compared with the baseline exam in all but one patient. CONCLUSIONS: The histological presence of necrosis and of fibrosclerosis after CIRT at the histological analysis supports the previous clinical evidence on the efficacy of CIRT. Volumetric stability of the residual mass should be considered as a success of treatment. In cases of a volumetric increase of the mass, a CT needle biopsy should always be performed. In our series, during the follow-up, the FDG-PET was able to promptly detect an increased uptake in the case which later was histologically defined as dedifferentiated chordoma. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This systematic review focuses on 5 key elements that may improve the decision-making process in spondylodiscitis: the infective agent, segmental instability, abscess development, neurological compromise and focus of infection. MATERIALS AND METHODS: We included 64 studies published between May 2012 and May 2017, that reported both a description of the discitis and comparative data regarding the disease and its complications. RESULTS: The majority of cases were caused by Staphylococcus spp (40.3%) and involved the lumbosacral region (52.3%). 27.8% of cases were associated to neurological compromise, 30.4% developed an abscess, 6.6% were associated to instability, and 54.7% underwent surgery. The abscesses mostly involved the lumbosacral region (60.4%) with paravertebral localization; 32.6% of cases involved the thoracic region, showing mostly epidural localization; a small number of cases (7%) involved the cervical region, mostly with epidural localization. 95% of paravertebral abscesses were treated percutaneously, while 85.7% of epidural cases underwent “open” surgery. Spinal cord compression mainly occurred in the cervical region (55.9%), neurological deficit was observed in over half of cases (65%), and surgery was required in most of the cases (83.9%). The majority of cases of instability involved the lumbosacral region (53.3%) and underwent surgery (87%). The focus of infection was mostly lumbosacral (61%) and almost all cases (95%) were treated surgically. CONCLUSIONS: Spondylodiscitis is a complex and multifactorial disease, whose diagnosis and management are still challenging. Due to its potential morbidity, it is extremely important to investigate the 5 key elements discussed in this paper in order to provide an early diagnosis and initiate the most effective treatment. [ABSTRACT FROM AUTHOR]

Purpose The aim of this study was to evaluate the dosimetric impact caused by recently introduced carbon fiber reinforced polyetheretherketone (CF/PEEK) stabilization devices, in comparison with conventional titanium (Ti) implants, for post-operative particle therapy (PT). Methods As a first step, protons and carbon ions Spread-Out Bragg Peaks (SOBPs) were delivered to CF/PEEK and Ti screws. Transversal dose profiles were acquired with EBT3 films to evaluate beam perturbation. Effects on image quality and reconstruction artifacts were then investigated. CT scans of CF/PEEK and Ti implants were acquired according to our clinical protocol and Hounsfield Unit (HU) mean values were evaluated in three regions of interest. Implants and artifacts were then contoured in the sample CT scans, together with a target volume to simulate a spine tumor. Dose calculation accuracy was assessed by comparing optimized dose distributions with Monte Carlo simulations. In the end, the treatment plans of nine real patients (seven with CF/PEEK and two with Ti stabilization devices) were retrospectively analyzed to evaluate the dosimetric impact potentially occurring if improper management of the spine implant was carried out. Results As expected, CF/PEEK screw caused a very slight beam perturbation in comparison with Ti ones, leading to a lower degree of dose degradation in case of contouring and/or set-up uncertainties. Furthermore, CF/PEEK devices did not determine appreciable HU artifacts on CT images thus improving image quality and, as a final result, dose calculation accuracy. Conclusions CF/PEEK spinal fixation devices resulted dosimetrically more suitable than commonly-used Ti implants for post-operative PT. [ABSTRACT FROM AUTHOR]