Ottobock (Germany)

Background: Targeted muscle reinnervation (TMR) is increasingly used to enhance prosthetic control and to reduce post-amputation pain. Its implementation across new centers raises questions about the reproducibility of outcomes and the impact of surgical experience. Methods: We compared the first three TMR patients treated in a newly established center in Nantes, France, with three patients treated in a high-volume center in Göttingen, Germany. Functional outcomes were measured using the Box and Block test (BBT), and operative time was recorded. Two French cases were performed with the assistance of a Göttingen-based surgeon. Conclusions: The functional outcomes showed a similar trend in both groups. The mean BBT scores were equivalent, suggesting reliable reinnervation and prosthetic integration even in early cases. Operative times were longer in Nantes, but did not impact outcomes. TMR appears not to have a pronounced learning curve, particularly regarding functional success in early cases under guided protocols. Factors such as assistance from experienced surgeons and favorable donor-to-recipient nerve ratios likely contribute to consistent outcomes. These findings support the reproducibility of TMR across institutions. Results: Within the first two years of rehabilitation we observed improvements in both functional performance and patient-reported quality of life. All six patients across both centers in-creased in BBT scores. All the patients reported an increase in social relationships and psychological health, and two of three patients reported an increase in physical health. Importantly, all six patients discontinued the use of pain medication at 2 years fol-lowing TMR. Furthermore, the French patients reported a decrease from 65–82 mm to 0–31 mm across the patients’ Visual Analog Scale (VAS) pain scores.

BackgroundRestoring the ability to walk with a prosthesis is considered a fundamental rehabilitation goal after transfemoral amputation. An essential prerequisite for achieving this goal is adequate force transmission between the prosthesis and the body. Does bone anchorage of an artificial limb permit a more normal force transmission? MethodsData of 15 healthy subjects, nine amputees fitted with bone-anchored prostheses, nine amputees using socket prostheses, and 18 patients with a total hip replacement were included in this multicenter, observational study. Ground reaction force was measured using Kistler force plates. Kinematics was recorded with 12 Vicon Bonita cameras. Subjects were instructed to walk at three different speeds: first at their self-selected, then at slow, and finally at fast speed. FindingsSelf-selected walking speeds of subject groups were significantly different, osseointegrated amputees walked the slowest. The lowest ground reaction force was measured for osseointegrated amputees on the prosthetic side, who also showed the highest force on their contralateral side. Patients with hip replacements showed values similar as healthy subjects. The vertical center of gravity movement was specific for each subject group. InterpretationThe force transmission capacity of the bone-anchored prosthetic leg is limited during walking and is lower than both in socket prostheses users without symptoms and patients with total hip replacement. Therefore, active amputees well fitted with a socket prosthesis who consider a transition to bone-anchorage should be advised that their walking speed may decrease with high probability, and that their self-selected walking speed may even be slower than 3 km/h.

Study designIn vitro human cadaveric biomechanical analysis.ObjectivesOptimization of prostheses for cervical disc arthroplasties (CDA) reduces the risk of complications. The instantaneous helical axis (IHA) is a superior parameter for examining the kinematics of functional spinal units. There is no comprehensive study about the IHA after CDA considering all 3 motion dimensions.MethodsTen human functional spinal units C4-5 (83.2 ± 7.9 yrs.) were examined with an established measuring apparatus in intact conditions (IC), and after CDA, with 2 different types of prostheses during axial rotation, lateral bending, and flexion/extension. Eccentric preloads simulated strains. The IHA orientation and its position at the point of rest (IHA0-position) were analyzed.ResultsThe results confirmed the existing data for IHA in IC. Lateral preloads showed structural alterations of kinematics after CDA: During axial rotation and lateral bending, the shift of the IHA0-position was corresponding with the lateral preloads’ applied site in IC, while after CDAs, it was vice versa. During lateral bending, the lateral IHA orientation was inclined, corresponding with the lateral preloads’ applied site in the IC and oppositely after the CDAs. During flexion/extension, the lateral IHA orientation was nearly vertical in the IC, while after CDA, it inclined, corresponding with the lateral preloads’ applied site. The axial IHA orientation rotated to the lateral preloads’ corresponding site in the IC; after CDA, it was vice versa.ConclusionBoth CDAs failed to maintain physiological IHA characteristics under lateral preloads, revealing a new aspect for improving prostheses’ design and optimizing their kinematics.

BackgroundOne of the drawbacks of lower-limb prostheses is that they do not provide explicit somatosensory feedback to their users. Electrotactile stimulation is an attractive technology to restore such feedback because it enables compact solutions with multiple stimulation points. This allows stimulating a larger skin area to provide more information concurrently and modulate parameters spatially as well as in amplitude. However, for effective use, electrotactile stimulation needs to be calibrated and it would be convenient to perform this procedure while the subject is seated. However, amplitude and spatial perception can be affected by motion and/or physical coupling between the residual limb and the socket. In the present study, we therefore evaluated and compared the psychometric properties of multichannel electrotactile stimulation applied to the thigh/residual limb during sitting versus walking.MethodsThe comprehensive assessment included the measurement of the sensation and discomfort thresholds (ST & DT), just noticeable difference (JND), number of distinct intervals (NDI), two-point discrimination threshold (2PD), and spatial discrimination performance (SD). The experiment involved 11 able-bodied participants (4 females and 7 males; 29.2 ± 3.8 years), 3 participants with transtibial amputation, and 3 participants with transfemoral amputation.ResultsIn able-bodied participants, the results were consistent for all the measured parameters, and they indicated that both amplitude and spatial perception became worse during walking. More specifically, ST and DT increased significantly during walking vs. sitting (2.90 ± 0.82 mA vs. 2.00 ± 0.52 mA; p < 0.001 for ST and 7.74 ± 0.84 mA vs. 7.21 ± 1.30 mA; p < 0.05 for DT) and likewise for the JND (22.47 ± 12.21% vs. 11.82 ± 5.07%; p < 0.01), while the NDI became lower (6.46 ± 3.47 vs. 11.27 ± 5.18 intervals; p < 0.01). Regarding spatial perception, 2PD was higher during walking (69.78 ± 17.66 mm vs. 57.85 ± 14.87 mm; p < 0.001), while the performance of SD was significantly lower (56.70 ± 10.02% vs. 64.55 ± 9.44%; p < 0.01). For participants with lower-limb amputation, the ST, DT, and performance in the SD assessment followed the trends observed in the able-bodied population. The results for 2PD and JND were however different and subject-specific.ConclusionThe conducted evaluation demonstrates that electrotactile feedback should be calibrated in the conditions in which it will be used (e.g., during walking). The calibration during sitting, while more convenient, might lead to an overly optimistic (or in some cases pessimistic) estimate of sensitivity. In addition, the results underline that calibration is particularly important in people affected by lower-limb loss to capture the substantial variability in the conditions of the residual limb and prosthesis setup. These insights are important for the implementation of artificial sensory feedback in lower-limb prosthetics applications.

Abstract In der Rehabilitationsmedizin kommen Exoskelette schon lange Zeit erfolgreich zum Einsatz. Als den Körper anliegende mechanische Strukturen stabilisieren und entlasten sie sowohl Gliedmaßen als auch den Rumpf. Inzwischen verbreiten sich diese Assistenzsysteme auch im industriellen Umfeld.

OCCUPATIONAL APPLICATIONS Globalization and eCommerce continue to fuel unprecedented growth in the logistics and warehousing markets. Simultaneously, the biggest bottleneck for these industries is their human capital. Where automation and robotic solutions fail to deliver a return on investment, humans frequently take over handling tasks that place harmful loads and strains on the body. Occupational exoskeletons can reduce fatigue and strain by supporting the lower spine and are designed to prevent work-related musculoskeletal disorders and other injuries. They are a mid- to long-term investment for industries to improve ergonomic conditions in workplaces, with the potential for reducing absences from work, sick days logged, and workers compensation claims. To examine the effectiveness of the newly introduced Paexo Back exoskeleton, a study was completed with 10 participants who completed manual load handling tasks with and without the exoskeleton. Key findings include significant reductions in metabolic effort and low back loading when the exoskeleton is worn.