No abstract

No abstract

Medical implants and prostheses (artificial hips, tendono- and ligament plasties) usually are multi-component systems that may be machined from one of three material classes: metals, plastics and ceramics. Typically, the body-sided bonding element is bone.The purpose of this contribution is to describe developments carried out to optimize the techniques , connecting prosthesis to bone, to be joined by an adhesive bone cement at their interface. Although bonding of organic polymers to inorganic or organic surfaces and to bone has a long history, there remains a serious obstacle in realizing long-term high-bonding strengths in the in vivo body environment of ever present high humidity.Therefore, different pretreatments, individually adapted to the actual combination of materials, are needed to assure long term adhesive strength and stability against hydrolysis. This pretreatment for metal alloys may be silica layering; for PE-plastics, a specific plasma activation; and for bone, amphiphilic layering systems such that the hydrophilic properties of bone become better adapted to the hydrophobic properties of the bone cement. Amphiphilic layering systems are related to those developed in dentistry for dentine bonding.Specific pretreatment can significantly increase bond strengths, particularly after long term immersion in water under conditions similar to those in the human body. The bond strength between bone and plastic for example can be increased by a factor approaching 50 (pealing work increasing from 30 N/m to 1500 N/m).This review article summarizes the multi-disciplined subject of adhesion and adhesives, considering the technology involved in the formation and mechanical performance of adhesives joints inside the human body.

Neurofunctional alterations in acute posttraumatic stress disorder (PTSD) and changes thereof during the course of the disease are not well investigated. We used functional magnetic resonance imaging to assess the functional neuroanatomy of emotional memory in surgical patients with acute PTSD. Traumatic (relative to non-traumatic) memories increased neural activity in the amygdala, hippocampus, lateral temporal, retrosplenial, and anterior cingulate cortices. These regions are all implicated in memory and emotion. A comparison of findings with data on chronic PTSD suggests that brain circuits affected by the acute disorder are extended and unstable while chronic disease is characterized by circumscribed and stable neurofunctional abnormalities.

There is a great need to establish reproducible methods for evaluative studies of wound treatment and wound healing. Validation of the healing process through optical techniques, as well as histologic and immunohistochemical methodologies, have been improved and to some extent have become well-established assays. Data relating to biomechanical properties, e.g., evaluation of the tensile strength of scar tissue that forms in experimental wound treatment strategies, are less widely available. We chose the domestic pig as an animal model in which to examine epidermal wound healing. We implanted specially made chambers that served to isolate the wounds and prevent epidermal migration from the edges. We performed histologic and immunohistochemical analyses as well as evaluation of biomechanical qualities of scar tissue using laser tensiometry. Pig skin is well suited for wound healing studies, and wound creation, implantation of the chambers, and the regular changing of dressings could all be carried out in the operating theater. In addition to established macroscopic evaluation and microscopic documentation, the need for objective biomechanical assessment of scar tissue by measuring tensile strength has been met using laser tensiometry. By optimizing methods for measuring tensile strength, it is possible to evaluate the biomechanical quality of scar tissue formed following different courses of wound treatment, as well as histologic assessment.

Using the minimally invasive PCCP technique in unstable pertrochanteric femur fractures provides a promising therapy option especially with regard to surgical time, radiographic screening time and failure rate. Lag screw sliding was low. There was no advantage of the intramedullary device PFN.

Surface EMG detected simultaneously at different muscles has become an important tool for analysing the gait of children with cerebral palsy (CP), as it offers essential information about muscular coordination. However, the interpretation of surface EMG is a difficult task that assumes extensive knowledge and experience. As such, this noninvasive procedure is not frequently used in the general clinical routine. An Artificial Intelligence (AI) system for interpreting surface EMG signals and the resulting muscular coordination patterns could overcome these limitations. To support such interpretation, an expert system based on fuzzy inference methodology was developed. The knowledge-base of the system implemented 15 rules, from which the fuzzy inference methodology performs a prediction of the effectiveness of the muscular coordination during gait. Our aim was to assess the feasibility and value of such an expert system in clinical applications. Surface EMG signals were recorded from the tibialis anterior, soleus muscle, and gastrocnemius muscles of children with CP to assess muscular coordination patterns of ankle movement during gait. Nineteen children underwent 114 surface EMG measurements. Simultaneously, the gait cycles of each patient were determined using foot switches and videotapes. From the EMG signals, the effectiveness of the ankle movement was predicted by the expert system, and predictions were classified using a three-point ordinal scale. In 91 cases (80%), the clinical findings matched the predictions of the expert system. In 23 cases (20%) the predictions of the expert system differed from the clinical findings with 12 cases revealing worse and 11 cases revealing better results in comparison to the clinical findings. As this study is a first attempt to verify the feasibility and correctness of this expert system, the results are promising. Further study is required to assess the correlation with the kinematic data and to include the whole leg. ß

No abstract