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Study design Retrospective cohort study.Objectives This study aimed to investigate the failure of the caudal end of lumbar posterior fixation in terms of pre-operative and post-operative spinopelvic parameters, correction performed, demographic and clinical data.Methods The lumbar, thoraco-lumbar and lumbo-sacral posterior fixations performed with pedicle screws and rods in 2017-2019 were retrospectively analyzed. As 81% failures occurred within 4 years, an observational period of 4 years was chosen. The revision surgeries due to the failure in the caudal end were collected in the junctional group. Fixations which have not failed were gathered in the control group. The main spinopelvic parameters were measured for each patient on standing lateral radiographs with the software Surgimap. Demographic and clinical data were extracted for both groups.Results Among the 457 patients who met the inclusion criteria, the junctional group included 101 patients, who required a revision surgery. The control group collected 356 primary fixations. The two most common causes of revision surgeries were screws pullout (57 cases) and rod breakage (53 cases). SVA, PT, LL, PI-LL and TPA differed significantly between the two groups (P= .021 for LL, P< .0001 for all the others). The interaction between the two groups and the pre-operative and post-operative conditions was significant for PT, SS, LL, TK, PI-LL and TPA (P< .005). Sex and BMI did not affect the failure onset.Conclusions Mechanical failure is more likely to occur in patients older than 40 years with a thoraco-lumbar fixation where PT, PI-LL and TPA were not properly restored.

Self-powered direct X-ray detectors, based on FAPbBr3255-nm-thick films deposited onto mesoporous TiO2scaffolds, can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss, demonstrating ultra-high operational stability.Bulk specific sensitivity is evaluated to be 7.28 C Gy−1cm−3at 0 V, an unprecedented value in the field of thin-film-based photoconductors and photodiodes for “hard” X-rays. Sensitivity of submicrometer-thick perovskite films to the X-rays produced by a medical linear accelerator used for cancer treatment is here demonstrated for the first time.

A single-crystal diamond sample grown by high-pressure high-temperature (HPHT) technique was used for the fabrication of a metal–semiconductor–metal (MSM) photoconductor. The sample quality was evaluated by means of spectral photocurrent measurements highlighting the presence of a significant density of defect states within the diamond bandgap, responsible for trap-mediated conduction mechanisms. The photoconductor was fully characterized under 6 MeV pulsed X-rays, sourced by a medical linear accelerator (LINAC), in the 0.05–20 Gy and 0.017–0.100 Gy/s dose (D) and dose-rate (DR) ranges, respectively. Photocurrent measurements performed with a conventional precision electrometer showed that the detector performance is strongly affected by charge-trapping phenomena, resulting in a sublinear dependence with the DR (power-law dependence with an exponent of 0.86). Measurements were repeated in the same experimental conditions by coupling the detector to a specifically developed gated integrator, allowing for a synchronous integration of photocurrent pulses (limited to 40 $\mu \text{s}$ ) centered on each impinging X-ray pulse. In this case, the detector photoresponse showed an excellent linearity with both the D and the DR (power-law dependence with 1.0009 ± 0.0004 and 1.009 ± 0.005 exponents, respectively). Significantly, the proposed synchronous integration technique is then able to mitigate the detrimental effect that defects have on detector performance. The proposed method paves, therefore, the way to the exploitation of HPHT diamond as a low-cost alternative to single-crystal chemical vapor deposition (CVD)-diamond for the fabrication of accurate and linear X-ray dosimeters.

Percutaneous vertebroplasty with polymethylmethacrylate (PMMA) restores the stiffness and the strength of fractured vertebral bodies, but changes the pattern of the stress transfer. This effect may cause a secondary fracture of the adjacent vertebrae. Elastoplasty has emerged as a new technique to overcome this complication. The aim of this study is to retrospectively evaluate the clinical results of the elastoplasty procedure.

The need for large active volume detectors for ionizing radiations and particles, with both large area and thickness, is becoming more and more compelling in a wide range of applications, spanning from X‐ray dosimetry to neutron spectroscopy. Recently, 8.0 × 8.0 mm2wide and 1.2 mm thick single‐crystal diamond plates have been put on the market, representing a first step to the fabrication of large area monolithic diamond detectors with optimized charge transport properties, obtainable up to now only with smaller samples. The more‐than‐double thickness, if compared to standard plates (typically 500 µm thick), demonstrated to be effective in improving the detector response to highly penetrating ionizing radiations, such as γ‐rays. Here we report on the first measurements performed on large active volume single‐crystal diamond plates, both in the dark and under irradiation with optical wavelengths (190–1100 nm), X‐rays, and radioactive γ‐emitting sources (57Co and 22Na).

Surface texturing by fs‐laser pulses has been performed in order to enhance optical absorptance of chemical vapour deposited diamond. The induced surface structures have been studied as a function of treatment dose D. Periodic structure with ripples of 170 nm has been observed for a D= 5.0 kJ cm−2, although not well defined texturing and damaged structures have been obtained for both lower and higher doses. Raman investigations point out negligible changes in crystal bulk for all investigated samples, thus suggesting that physical properties of the crystal were not changed by the treatment. Optical absorptance is strongly enhanced by fs‐laser texturing and it is an increasing function of the treatment dose. The absorptance of solar spectrum saturates up to values larger than 90%. The obtained outstanding enhancement of photon absorption represents a preliminary and promising step for the exploitation of synthetic diamond in future high‐efficient conversion devices for solar concentration based on photon‐enhanced thermionic emission effect.

First neutron and X‐ray beam tests on a novel 12‐pixel single‐crystal diamond mosaic detector are presented and discussed. Preliminary characterization of single‐pixel electronic properties, performed with α particles, results in charge carrier mobilities >2000 cm2Vs−1and saturation velocities of the order of 107cm s−1. Signal stability over time, measured with a 241Am source (37 kBq activity), is longer than 5 h. Tests under an intense X‐ray beam (1 Gy h−1dose‐rate) show a very good response uniformity (down to about 1% of relative standard deviation from mean value), suggesting a high level of pixel reproducibility at intermediate bias voltages (ranging from 20 to 100 V). Response uniformity reduces at voltages >200 V, due presumably to radiation‐assisted detrapping effects. Preliminary results of 12‐pixel simultaneous acquisitions of X‐ray beam profiles and pulse height spectra under a fast neutron beam (14 MeV) are also presented.

Dielectric microspacers (DMS) are important components in thermal energy converters. Engineered DMS are fabricated and characterized on different substrates by depositing patterned ceramic thin films of alumina (Al2O3) and zirconia (ZrO2) with a thickness ranging from 0.3 to 3 μm. Both Al2O3and ZrO2films are electrically and thermally optimized, finding zirconia more suitable as a thermal and electrical insulating material at high temperature, whereas the developed DMS are morphologically analyzed by scanning electron microscopy. The analysis of thermal simulations carried out with COMSOL Multiphysics allows identifying the best geometrical constraints for each single structure, whereas simulations carried out by the Fluent software allow identifying the best arrangement for DMS, leading to a solution with optimized pattern in terms of amount and spatial distribution so to achieve the required electrical and thermal insulation for practical applications. DMS are integrated within thermionic‐photovoltaic devices to be validated experimentally, and enhanced electron emission measurements are successfully performed at a cathode temperature up to 1350 °C to verify the operational feasibility and potential of this technology. Dielectric microspacers are developed with RF reactive sputtering and a photolithographic technique for ensuring electrical and thermal insulation between the electrodes of high‐temperature energy converters. Nanostructured amorphous zirconia films are patterned according to a specific arrangement onto different substrates, and their working operations are demonstrated up to 1350 °C in hybrid thermionic‐photovoltaic devices.

Two-dimensional laser-induced periodic surface structures with a deep-subwavelength periodicity (80 nm ≈ λ/10) are obtained for the first time on diamond surfaces. The distinctive surface nanotexturing is achieved by employing a single step technique that relies on irradiation with two temporally delayed and cross-polarized femtosecond-laser pulses (100 fs duration, 800 nm wavelength, 1 kHz repetition rate) generated with a Michelson-like interferometer configuration, followed by chemical etching of surface debris. In this Letter, we demonstrate that, if the delay between two consecutive pulses is ≤2 ps, the 2D periodicity of nanostructures can be tuned by controlling the number of pulses irradiating the surface. Under scanning mode, the method is effective in treating uniformly large areas of diamond, so to induce remarkable antireflection properties able to enhance the absorptance in the visible up to 50 times and to pave the route toward the creation of metasurfaces for future diamond-based optoelectronic devices.

Black diamond, obtained by femtosecond laser treatment of natively transparent diamond, is a promising material for solar applications. The enhancement of the interaction between the active material and the solar spectrum is obtained by a controlled texturing of the diamond surface at the nanoscale, the impact of which on the optical and electronic properties of the bulk material is strongly influenced by the laser parameters. In this work, the properties of black diamond samples obtained by using two different laser wavelengths (400 and 800 nm) are compared, showing that texturing periodicity (80 and 170 nm, respectively) is strictly related to the laser wavelength used. Conversely, a unique optimal accumulated absorbed laser fluence (2.10 kJ cm−2) demonstrated to return the best results in terms of responsivity in the solar spectrum, regardless of the wavelength used for laser treatment. Black diamond is a brand new material, obtained by laser treatment of white diamond, with outstanding optical absorption properties. However, for solar energy conversion applications, it is necessary to improve its responsivity. This work compares the optoelectronic properties of black diamonds obtained with two different laser wavelengths (400 and 800 nm), showing that 800 nm is a better choice.

Introduction Spinal infections are rare diseases, whose management highlights the importance of a multidisciplinary approach. Although treatment is based on antibiotics, always selected on coltural and antibiogram tests, surgery is required in case of development of spinal instability or deformity, progressive neurological deficits, drainage of abscesses, or failure of medical treatment. The first step of the algorithm is diagnosis, which is established on MRI with contrast, PET/CT scan, blood tests (CRP and ESR) and CT-guided needle biopsy. Evaluation of response to the specific antibiotic therapy is based on variations in Maximum Standardized Uptake Value (SUVmax) after 2 to 4 weeks of treatment. In selected cases, early minimally invasive surgery was proposed to provide immediate stability and avoid bed-rest.Material and Methods From 1997 to 2014, 182 patients affected by spinal infections have been treated at the same institution (Istituto Ortopedico Rizzoli – Bologna, Italy) according to the proposed algorithm. Mean age was 56 years (range 1 - 88). Male to female ratio was 1,46.Results Minimum follow-up was 1 year. Infections were mostly located in the lumbar spine (57%) followed by thoracic (37%) and cervical spine (6%). Conservative treatment based on antibiotics needed surgery (open and/or percuteneous minimally invasive) as an adjuvant in 83 patients out of 182 (46%).Conclusion Management of spinal infections still remains a challenge in spinal surgery and multisciplinary approach is mandatory. This algorithm represents the shared decision making process from diagnosis to the most appropriate treatment, led to successful outcomes with a low-complication rate.

Introduction The surgical approach to adult deformities is challenging both in terms of surgical planning and of amount of complications. Current literature shows potential benefits in surgical correction of adult deformities; recovery of both frontal and sagittal balance seems to be the key for satisfactory outcomes.Patients and Methods In this retrospective study, from an initial pattern of 30 patients, 12 selected patients were considered. All patients, average age 57 years, underwent adult scoliosis surgical correction. We evaluated the clinical outcomes in correlation with restoring of the sagittal balance and the rate of complications and mechanical failure. Previous surgery was not an exclusion criteria. Average follow-up was 8.2 months (range, 3–20 months). Clinical evaluation was performed by using Visual Analog Score test, Oswestry Disability Index, and Quality of Life test. Radiological measures were performed by software Surgimap Spine.Results In 10 cases (83% of patients), we observed agreement between clinical and radiological outcomes (we focused in particular on sagittal balance). To a satisfactory recovery of sagittal balance, in eight cases we found improvement at clinical tests while in two cases to a poor balance correction, the patients' quality of life did not improve. In only two cases (16% of patients), we found disagreement between the two parameters indicated (sagittal balance and quality of life). In our series, five patients had mechanical failures: four of them did not improve their sagittal balance at postoperative X-ray.Conclusion The purpose of this study was to validate the hypothesis that good clinical results in adult deformities correction are better achieved when restoration of sagittal balance is obtained. The large agreement among quality of life evaluation and recovery of sagittal balance we observed in this preliminary series of selected patients seems to hold it up. Moreover, the respect of physiological pelvic parameters seems to reduce the number of adverse events in terms of mechanical failures and consequently the number of reoperations; its indeed necessary to underline how 100% of patients whose sagittal balance did not improve with surgery had mechanical failure of instrumentation. Only one patient with acceptable sagittal parameters needed reoperation because of breaking of the rods.