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BACKGROUND: In general, sufficient anchoring of screws in the bone material ensures the intended primary stability. METHODS: Shape memory materials offers the option of using temperature-associated deformation energy in a targeted manner in order to do justice to the special situation of osteoporotic bones or the potential lack of anchoring. An expansion screw was developed that takes this possibility and these requirements into account. Using finite element analysis, the variability of screw configuration and actuator was assessed from shape memory. In particular, the dimensioning of the screw slot, the actuator length and the actuator diameter as well as the angle of attack in relation to the intended force development were considered. RESULTS: As a result of the finite element analysis, a special configuration of expansion screw and shape memory element could be found. Accordingly, with an optimal screw diameter of 4 mm, an actuator diameter of 0.8 mm, a screw slot of 7.8 mm in length and an angle of attack of 25 degrees, the best compromise between individual components and high efficiency in favor of maximum strength can be predicted. CONCLUSION: Shape memory material offers the possibility of using completely new forms of power development. By skillfully modifying the mechanical and shape memory elements, their interaction results in a calculated development of force in favor of a high primary stability of the screw material used. Activation by means of body temperature is a very elegant way of initializing the intended locking and screw strength.
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Introduction: Individuals with Parkinsonian disorders often face limited access to specialized physiotherapy and movement training due to staff shortages and increasing disease incidence, resulting in a rapid decline in mobility and feelings of despair. Addressing these challenges requires allocating adequate resources and implementing specialized training programs to ensure comprehensive care and support. Regarding these problems, a computer software was invented that might serve as an additional home-based extension to conventional physiotherapy. Methods: The trial took place in a rehabilitation center where every patient received equivalent treatment apart from the training program that was set up to be investigated over 3 weeks. Seventy four Patients were included and randomized between two intervention and one control group. Intervention group 1 (IG1) trained with the computer-based system two times a week while Intervention group 2 (IG2) received five training sessions a week. Using the markerless Microsoft Kinect® camera, participants controlled a digital avatar with their own body movements. UPDRS-III and Clinical measurements were performed before and after the three-week period. Results: Patients in all groups improved in UPDRS-III pre and post intervention whereas reduction rates were higher for IG1 (-10.89%) and IG2 (-14.04%) than for CG (-7.74%). Differences between the groups were not significant (value of ps CG/IG1 0.225, CG/IG2 0.347). Growth rates for the arm abduction angle were significantly higher in IG1 (11.6%) and IG2 (9.97%) than in CG (1.87%) (value of ps CG/IG1 0.006 and CG/IG2 0.018), as was the 5-steps-distance (CG 10.86% vs. IG1 24.5% vs. UG2 26.22%, value of ps CG/IG1 0.011 and CG/IG2 0.031). Discussion: The study shows the beneficial effects of computer-based training and substantiates the assumption of a similar impact in a home-based setting. The utilized software is feasible for such interventions and meets with the patient's approval. Group dynamics seem to have an additional supporting effect for the aspired objective of improving mobility and should be seen as an essential aspect of video games in therapy.
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OBJECT: The individualized Starfix® miniframe belongs to a new generation of stereotactic systems enabling high-precision electrode placement with considerably better time-efficiency in deep brain stimulation (DBS). We evaluated the usability and reliability of this novel technique in patients with idiopathic Parkinson's disease (IPD) and compared surgical and clinical results with those obtained in a historical group in which a conventional stereotactic frame was employed. METHODS: Sixty patients underwent surgery for implantation of DBS electrodes in the subthalamic nucleus. In 31 of them (group I) a conventional Zamorano-Dujovny frame was used and in 29 of them (group II) a Starfix® miniframe was used. Image fusion of preoperatively acquired 3D T1w and T2w 1.5 T MR-image series was used for the targeting procedure. Placement of the test electrodes and permanent electrodes corresponded to standard functional neurosurgery and included microelectrode recording and macrostimulation. Clinical (L-Dopa equivalent dose, United Parkinson's disease rating scale part III) and time for surgical electrode implantation were evaluated postoperatively in a 3-, 6- and 12-month follow-up. RESULTS: Twelve months postoperatively, L-Dopa dose was significantly reduced from 685.19 to 205.88 mg/day and from 757.92 to 314.42 mg/day in groups I and II, respectively. A comparable reduction of the LED could be observed 1 year after surgery. Motor function has improved in a significant and identical manner with 59% (group I) and 61% (group II). Besides clinical effects by stimulation therapy there was a significantly reduced surgery time required for electrode implantation using the Starfix® miniframe (group I: 234.1 min, group II: 173.6 min; p < 0.001). CONCLUSIONS: Individualized miniframes such as the Starfix® miniframe allow implantation of DBS electrodes in IPD that is equally effective as conventional systems. The time efficiency achieved in surgery using of the Starfix® system helps to minimize patients' discomfort during DBS surgery.