The interlocking lag screw design reduced movement of the femoral head and relative movement between fracture fragments. Beyond that the trapezoidal nail design of the Intertan reduced toggling within the trochanteric area and prolonged survival. Although this study showed a decrease in the retention of stability over time, failure did not occur until the equivalent of 2-3 months of reduced physical activity in which healing may have occurred under normal clinical conditions.

Background Minimally invasive, thoracoscopic anterior spondylodesis (MIAS) is an established treatment for burst fractures of the thoracolumbar spine. Good restoration of the local sagittal alignment and good functional results have been reported. The aim of this study was to evaluate long-term results of MIAS in patients with incomplete burst fractures and to analyze the influence on global sagittal alignment, clinical outcomes, and adjacent segment degeneration. Methods From 2002 to 2003, 18 patients were treated with MIAS for incomplete thoracolumbar burst fractures. Mono-segmental spondylodesis was performed with an iliac crest bone graft and bisegmental spondylodesis with a titanium cage. In this single-center prospective cohort study, 15 patients were available for follow-up (FU) after an average of 12.9 years (12.1–14.4). Seven patients were treated with a combined anterior and posterior instrumentation and eight patients with anterior spondylodesis only. The primary clinical outcome parameter was the Oswestry Disability Index (ODI); secondary parameters were the Short Form 36 (SF36) and the visual analog scale (VAS spine). Full spine radiographs were assessed for bisegmental Cobb angle, alignment parameters, and signs of adjacent segment degeneration (ASD). Results ODI evaluation showed a mean impairment of 11.7% with minimal limitations in 13 patients. Neither a significant deterioration over time nor significant differences between both therapy strategies were found in the clinical scores at the latest follow-up. The mean bisegmental increase of regional malalignment of reduction was 8.8° (± 7.3°) with no significant correlation to any clinical outcome scores. The majority of patients had no signs of adjacent segment degeneration. Two patients showed minor radiologic changes. All patients had a balanced sagittal spine profile. Conclusions In conclusion, MIAS leads to good clinical results with—in majority—minimal spine-related impairment at the latest follow-up. No significant deterioration at 12-year FU was detectable compared to the 6-year results for the SF36 and VAS spine scores. There was no association between sagittal alignment, clinical outcome scores, and ASD. Trial registration The study was retrospectively registered in the German Clinical Trials Register (Nr.00015656).

Powder-based laser metal deposition is a well-established generative manufacturing process in the field of tool and mould building to produce or repair components. Conventionally manufactured tools are often completely constructed of a high-alloyed, hardened-tempered, and expensive tool steel. An alternative way to manufacture tools and moulds is the combination of a cost-efficient, mild steel, and a functional coating. Such specific, locally adapted coating can be generated by laser metal deposition. The functional coating is just located in the area of the interaction zone of the tool. Consequently, costs and resources can be saved. Such coatings are created by positioning multiple individual weld tracks next to and on top of each other in an overlapping manner. It is therefore useful to characterize und optimize the individual weld track. Thermal processing methods, like a laser metal deposition, are always characterized by thermal distortion. The resistance against the thermal distortion of the work piece is decreasing with the reduction of the material thickness. Thus, there is a special process management for the laser based coating of thin-walled parts or tools with a small material thickness needed to reduce thermal distortion. The experimental approach in the present paper is to keep the energy and the mass per unit length constant by varying the laser power, the feed rate, and the powder mass flow. The typical seam parameters (such as width, height and depth, cross-sectional area, and angular distortion) are measured in order to characterize the cladding process, define process limits, and evaluate the process efficiency of an individual weld track. Ways to optimize dilution, angular distortion, and clad height are presented. After the characterization of individual weld tracks, optimized process parameters are deduced from the process window and used to create functional, two-dimensional coatings on thin substrates. Different scanning strategies are compared with each other to reduce processing time and thermal distortion.