Introduction and Objective. The treatment of severe deformities often requiring aggressive techniques such as vertebral resection and osteotomies with high comorbidity. To mitigate this risk, several methods have been used to achieve a partial reduction of stiff curves. The objective of this study was to evaluate and quantify the effectiveness of the Perioperative Halo-Gravity Traction (HGT) in the Treatment of Severe Spinal Deformity in Children. Materials and Methods. A historical cohort of consecutive childs with severe spinal deformity who underwent to a perioperative HGT as a part of the treatment protocol. Minimum follow-up of 2 years. Demographic, clinical and radiological data, including time duration of perioperative HGT and Cobb angle in the coronal and sagittal plane. The radiological variables were measured before the placement of the halo, after placement of the halo, at the end of the period of traction, after surgery and in the final follow-up. Results. Seventeen males (57%) and twenty females (43%) were included in the final analysis. The mean age was 6.5 years (SD 4.8). The most frequent etiology for the spinal deformity was syndromic (13 patients). The average preoperative Cobb angle was 88º (range, 12–135). HGT was used in 17 cases prior to a primary surgery and in 20 cases prior to a revision surgery. After the HGT, an average correction of 34% of the deformity was achieved (p <0.05). After the surgery this correction improved. At 2-year follow-up there was a correction loss of 20% (p <0.05). There were 3 complications (8.1%): 2 pin infections and cervical subluxation. Conclusions. The application of HGT in cases of severe rigid deformity is useful allowing a correction of the preoperative deformity of 34%, facilitating surgery. Preoperative HGT seems to be a safe and effective intervention in pediatric patients with high degree deformity

Summary Statement. The problem facing this research is to promote rapid osteointegration of titanium implants and to minimise the risks of infections by the functionalization with different agents, each designed for a specific action. A patented process gives a multifunctional titanium surface. Introduction. A patented process of surface modification is described. It gives a multifunctional surface with a multiscale roughness (micro and nano topography), that is excellent for osteoblast adhesion and differentiation. It has a high degree of hydroxylation, that is relevant for inorganic bioactivity (apatite-HA precipitation) and it is ready for a functionalization with biological factors. A direct grafting of ALP has been obtained. Moreover, the growth of an antibacterial agent within the surface oxide layer can be useful in order to combine the osteoinduction ability to antimicrobial effects. The selection of an inorganic agent (metal nanoparticles) has the advantage to avoid an eventual development of antibiotic resistance by bacteria. Experimental Methods. Ti-cp and Ti6Al4V samples were polished or blasted, etched in diluted hydrofluoric acid (step 1a), oxidised in hydrogen peroxide (step 1b), incubated in Tresyl chloride (step 2a) and Alkaline phosphatase (ALP) enzyme (step 2b) [1, 2]. A water solution, containing a salt of the metal to be added to the surface as an inorganic antibacterial agent, can be introduced during the oxidation in hydrogen peroxide. Surface morphology and chemical composition were investigated by Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive Spectroscopy (EDS). The composition of the outermost surface layer and the chemical state of elements were analyzed by X-Ray Photoelectron Spectroscopy (XPS). The activity of grafted enzyme was studied by an enzymatic activity test. In vitro bioactivity was evaluated by soaking the samples in simulated body fluid and SEM observation to verify hydroxyapatite (HA) precipitation. Antibacterial activity has been determined by inhibition halo test against S aureus. Results and Discussion. A peculiar multi-scale topography, with spongy-like nanometric features, was obtained after the inorganic treatment (step 1a-1b). This morphology can be superimposed on the micro-or macro roughness deriving from acid etching or blasting, by properly optimizing the process parameters. Moreover, the treated surfaces present a high density of hydroxyl groups (XPS data) and they are bioactive (HA precipitation after soaking in SBF for 15 days). Metal (Ag, Cu, Zn) nanoparticles can be grown within the surface oxide layer and they are effective as antimicrobial inorganic agents. The amount of the metal nanoparticles can be tailored in order to have an antibacterial or a bacteriostatic surface. The effective grafting of ALP (step 2a-2b) has been shown by XPS because of the appearance of characteristic peaks in the carbon region. Moreover, it has been observed that ALP maintains its activity after grafting by an enzymatic activity test. ALP grafting improves HA precipitation kinetics. Conclusions. An innovative process was applied to titanium surfaces in order to obtain a better bone integration ability and antibacterial activity. A multi scale surface topography (micro and nano features) was successfully obtained together with an high hydroxylation degree. Modified surfaces are able to induce hydroxyapatite precipitation in vitro and to graft ALP, maintaining its activity and improving bioactivity. Metal nanoparticles embedded in the surface oxide layer have an antibacterial effect