Search

Background: Surgical procedures on the lower extremities often require weight-bearing on crutches as part of the rehabilitation process. Orthopedic elective procedures enable patients to learn the correct use of crutches in a controlled preoperative setting. Digital assistance systems can safely circumvent a shortage of skilled staff and any contact restrictions that may be necessary., Objective: The usability of a newly developed gait training assistant (GTA) for the use of crutches will be evaluated. An intervention group trained to use crutches by the digital trainer will be compared with a control group trained to use crutches conventionally by a physiotherapist., Methods: As part of the development and implementation of a novel GTA, 14 patients learned to walk with crutches by completing specific exercises while receiving live feedback. Their movements were detected by a depth sensor and evaluated in real time. Specific parameters (step length, synchronous movement, crutch angle, and crutch distance to the feet) were compared with a control group (n=14) trained to use crutches by physiotherapists. The intervention group was also assessed by a physiotherapist. At the end of the study, the patients completed questionnaires to evaluate the usability of the system (Brooke's System Usability Scale score) and patient satisfaction., Results: All patients trained by the novel GTA were able to use crutches correctly. The intervention group showed significantly better values for crutch angle (mean -6.3°, SD 3.5° vs mean -12.4°, SD 4.5°; P<.001) and crutch position (mean 3.3, SD 5.1 cm vs mean -8.5, SD 4.9 cm; P=.02). Both groups reported that they felt confident in the use of crutches, were able to follow the instructions, and enjoyed the training. Even though the majority (12/14, 86%) preferred physical therapy over a purely digital approach, most participants enjoyed using the system (13/14, 93%) and were interested in trying out other digital assistants (11/14, 79%). The usability of the GTA was rated above average by the majority (9/14, 64%) of the patients., Conclusions: The newly designed GTA is a safe method of teaching the use of crutches and is statistically superior to training by a physiotherapist. Even if patients prefer interaction with a physiotherapist over a purely digital approach, digital devices provide a safe and motivating opportunity to learn the essential locomotor skills for rehabilitation., (©Milan Anton Wolf, Leon Sauerwald, Felix Kosmalla, Florian Daiber, Antonio Krüger, Stefan Landgraeber. Originally published in JMIR Human Factors (https://humanfactors.jmir.org), 16.08.2024.)

Shared automated mobility-on-demand promises efficient, sustainable, and flexible transportation. Nevertheless, security concerns, resilience, and their mutual influence - especially at night - will likely be the most critical barriers to public adoption since passengers have to share rides with strangers without a human driver on board. Prior research points out that having information about fellow travelers could alleviate the concerns of passengers and we designed two user interface variants to investigate the role of this information in an exploratory within-subjects user study (N=24). Participants experienced four automated day and night rides with varying personal information about co-passengers in a simulated environment. The results of the mixed-method study indicate that having information about other passengers (e.g., photo, gender, and name) positively affects user experience at night. In contrast, it is less necessary during the day. Considering participants' simultaneously raised privacy concerns, balancing security and privacy demands poses a substantial challenge for resilient system design., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: In case of injuries to the subaxial cervical spine, especially in osteoporotic bone, the question of the most stable operative technique arises. There are several techniques of screw fixation available regarding dorsal stabilization. This study investigates 2 techniques (lateral mass screws (LMS) vs cervical pedicle screws (CPS)) in the subaxial cervical spine regarding primary stability in a biomechanical testing using a translational injury model., Methods: A total of 10 human formalin fixed and 10 human fresh-frozen specimens (C 4 - T 1) were investigated. Specimens were randomized in 2 groups. Fracture generation of a luxation injury between C 5 and C 6 was created by a transection of all ligamentous structures as well as the intervertebral disc and a resection of the facet joints.Dorsal stabilization of C 4/C 5 to C 6/C 7 was performed in group A by lateral mass screws, in group B by pedicle screws. In the biomechanical testing, the specimens were loaded at 2 N/s in translation direction until implant failure., Results: Formalin fixed specimen: Mean load failure was 513.8 (±86.74) Newton (N) for group A (LMS) and 570.4 (±156.5) N for group B (CPS). There was no significant difference (P = .6905).Fresh frozen specimen: Mean load failure was 402.3 (±96.4) N for group A (LMS) and 500.7 (±190.3) N for group B (CPS). There was no significant difference (P = .4206)., Conclusion: In our loading model respecting the translational injury pattern and a flexion movement we could not verify statistically significant differences between lateral mass screws and cervical pedicle screws. Mean loading failure was slightly higher in the CPS group though., Competing Interests: All authors declare no conflict of interest with this work. LO, JR, TK, CB, SR, AK have no conflict of interest at all. MB gave lecture on that topic on the German Orthopaedic and Trauma Conference (DKOU 2018, Berlin)., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Spino-pelvic fixation has been widely accepted for surgical treatment of sacral tumor, scoliosis surgery and pelvic fractures. Cement augmentation of screws is an option to improve implant stability in osteoporotic bone quality. Aim of the present study is to compare iliac screw fixation without cement fixation and two cement application options in a biomechanical testing., Hypothesis: Cement augmentation of iliac screws leads to superior pull-out strength., Material and Methods: Thirty female and osteoporotic human iliac bones were used. Three operation treatment groups were generated: Screw fixation (cannulated screws) without cement augmentation [Operation treatment (OT) A], screw fixation with cement augmentation before screw placement (cannulated screws) (OT B) and screw fixation with perforated screws and cement augmentation after screw placement (OTC). Pull-out tests were performed with a rate of 6mm/min. A load versus displacement curve was generated. Maximum pull-out force (N) was measured in the load-displacement curve., Results: Paired group 1 (OT A vs. OT B): Screw fixation without cement augmentation: 592.6N±335.07 and screw fixation with cement augmentation before screw placement: 996N±287.43 (p=0.0042). Paired group 2 (OT A vs. OT C): screw fixation without cement augmentation: 716.2N±385.86 and fenestrated screw fixation with cement augmentation after screw placement: 1324.88N±398.76 (p=0.0489). Paired group 3 (OT B vs. OT C): Screw fixation with cement augmentation before screw placement: 1077.2±486.66 and fenestrated screw fixation with cement augmentation after screw placement: 1298.2N±726.19 (p=0.3286)., Discussion: Regarding iliac screw fixation for spino-pelvic ostesynthesis in osteoporotic bone, cement augmentation is significantly superior to solid iliac screw fixation respecting pull-out-strength. Nevertheless, further biomechanical studies are needed to verify these findings., Level of Evidence: Not applicable; biomechanical cadaver study., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Introduction: It has been shown that communication skills acquired during undergraduate medical education are of great importance. Hence, many countries require teaching communication as part of their medical curricula. To assess students' learning progress, "Catering to the Patient", as an aspect of showing empathy, should be evaluated. Since there was no description of a validated instrument fitting for this purpose, one had to be developed. To describe its process of development and its psychometric properties were the aims of this study. Methods: Based on the Calgary-Cambridge Observation Guide (CCOG), items describing catering to the patient were selected and modified. Cognitive pretest interviews were conducted to check understandability. Therefore, 7 raters assessed 1 video each (R=7, V=1). In a following pilot study (R=3, V=10) first psychometric properties were evaluated and necessary corrections in the preliminary evaluation form were carried out before the final evaluation form was used to assess students' ability to cater to the patient and psychometric properties were described in detail (R=2, V=35). Results: The final assessment instrument, "catering to the patient - Marburg evaluation form", contains 11 checklist items and two global ratings (items 12 and 13). In the final evaluation the inter-rater reliability (IRR) ranged from 0 to 0.562, the median was r =0.305. Concerning item 13 (a global rating), 88.6% of the videos were scored with the maximum difference of one point. The internal consistency was very high (Cronbach's α: α=0.937 and α=0.962), and the correlation between the checklist items and the global rating was high (Pearson's r : r=0.856 and r =0.898). Discussion: The assessment instrument "catering to the patient" is suitable for giving feedback and for using it in formative examinations. Its use for summative examinations can be considered. Further examinations should evaluate if a three-point Likert scale could reach higher values and if item 13 can be used as a stand-alone item., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2021 Urff et al.)

Background: Standard balloon kyphoplasty represents a well-established treatment option for osteoporotic vertebral compression fractures. Aim of the present study was to evaluate two different methods of percutaneous augmentation (standard balloon kyphoplasty (BKP) versus Tektona® (TEK)) with respect to height restoration., Methods: Four-teen vertebral bodies of two female cadavers were examined. Fractures were created using a standardized protocol. CT-scans were taken before and after fracture, as well as after treatment. Afterwards two groups were randomly assigned in a matched pair design: 7 vertebral bodies (VB) were treated with BKP (Kyphon, Medtronic) and 7 vertebral bodies by TEK (Spineart, Switzerland) Anterior, central and posterior vertebral body heights were evaluated by CT-scans. Volumetry was performed using the CT-scans at three different timepoints., Results: Values before fracture represent 100%. The anterior height after fracture was reduced to 75.99 (± 4.8) % for the BKP group and to 76.54 (± 9.17) % in the TEK Group. Statistically there was no difference for the groups (p = 1). After treatment the values increased to 93.06 (± 5) % for the BKP Group and 87.71 (± 6.2) % for the TEK Group. The difference before and after treatment was significant for both groups (BKP p = 0.0006; TEK p = 0.03). Within the groups, there was no difference (p = 0.13). The Volume of the vertebral body was reduced to 82.29 (± 8.4) % in the BKP Group and to 76.54 (± 8.6) % in the TEK Group. After treatment the volume was 89.26 (± 6.9) % for the BKP Group and 88.80 (± 8.7) % for the TEK Group. The difference before and after treatment was significant only for the TEK group (BKP p = 0.0728 n.s.; TEK p = 0.0175). Within the groups, there was no difference (p = 0.2). The average cement volume used was 6.1 (range 3.6-9 ml) for the BKP group and 5.3 (3-7.2 ml) for the TEK group respectively., Conclusions: Based on our results the new System Tektona® in osteoporotic compression fractures might represent a promising alternative for the clinical setting, especially preserving bone. Further biomechanical tests and clinical studies have to proof Tektona®`s capabilities.

Since its introduction by Metaizeau and Prevot, elastic-stable intramedullary nailing (ESIN) has been used for almost all diaphyseal fractures in children. Here, we present a retrospective study analyzing the long-term results of ESIN of forearm fractures in children.A total of 122 patients with diaphyseal forearm fractures and single subtypes in childhood were treated from 2000 to 2007 at our University Hospital by ESIN. At follow-up, the current conditions of the patients were evaluated using the Disabilities of Arm, Shoulder, and Hand (DASH) Score, and the Mayo Wrist score. Moreover, an individual questionnaire with 16 items was used to collect further information about the patient's condition and limitations as adults.The evaluation was performed at 12.4 years (average) after surgery. In our study population (n = 90), the average DASH scores for sports, performing arts, and work were 0.4 (standard deviation: 1.45), 0.9 (standard deviation: 5.68), and 0.3 (standard deviation: 7.39), respectively. Furthermore, 77% of our patients achieved a DASH Score of 0 (optimum outcome). The average Mayo Wrist Score was 97.64 (standard deviation: 7.39), and 82% of the study population achieved a score of 100 (optimum outcome). A correlation between the DASH and Mayo Wrist Scores was found in few patients. Overall, the DASH Score, Mayo Wrist Score, and results of our individual questionnaire demonstrated convincing point values.This study demonstrated favorable long-term results achieved by ESIN of forearm fractures in children. It seems that good outcomes, reported by various studies with short- to mid-term follow-up beforehand, do not deteriorate over time.Level of Evidence: Level III; retrospective study; therapeutic study.

Background: In the operative treatment of osteoporotic vertebral body fractures, a dorsal stabilization in combination with a corpectomy of the fractured vertebral body might be necessary with respect to the fracture morphology, whereby the osteoporotic bone quality may possibly increase the risk of implant failure. To achieve better stability, it is recommended to use cement-augmented screws for dorsal instrumentation. Besides careful end plate preparation, cement augmentation of the adjacent end plates has also been reported to lead to less reduction loss., Purpose: The aim of the study was to evaluate biomechanically under cyclic loading whether an additional cement augmentation of the adjacent end plates leads to improved stability of the inserted cage., Study Design/setting: Methodical cadaver study., Materials and Methods: Fourteen fresh frozen human thoracic spines with proven osteoporosis were used (T2-T7). After removal of the soft tissues, the spine was embedded in Technovit (Kulzer, Germany). Subsequently, a corpectomy of T5 was performed, leaving the dorsal ligamentary structures intact. After randomization with respect to bone quality, two groups were generated: Dorsal instrumentation (cemented pedicle screws, Medtronic, Minneapolis, MN, USA)+cage implantation (CAPRI Corpectomy Cage, K2M, Leesburg, VA, USA) without additional cementation of the adjacent endplates (Group A) and dorsal instrumentation+cage implantation with additional cement augmentation of the adjacent end plates (Group B). The subsequent axial and cyclic loading was performed at a frequency of 1 Hz, starting at 400 N and increasing the load within 200 N after every 500 cycles up to a maximum of 2,200 N. Load failure was determined when the cages sintered macroscopically into the end plates (implant failure) or when the maximum load was reached., Results: One specimen in Group B could not be clamped appropriately into the test bench for axial loading because of a pronounced scoliotic misalignment and had to be excluded. The mean strength for implant failure was 1,000 N±258.2 N in Group A (no cement augmentation of the adjacent end plates, n=7); on average, 1,622.1±637.6 cycles were achieved. In Group B (cement augmentation of the adjacent end plates, n=6), the mean force at the end of loading was 1,766.7 N±320.4 N; an average of 3,572±920.6 cycles was achieved. Three specimens reached a load of 2,000 N. The differences between the two groups were significant (p=.006 and p=.0047) regarding load failure and number of cycles., Conclusions: Additional cement augmentation of the adjacent end plates during implantation of a vertebral body replacement in osteoporotic bone resulted in a significant increased stability of the cage in the axial cyclic loading test., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The estimated incidence of osteoporotic pelvic fractures among persons over age 60 in Germany is 224 per 100 000 persons per year, and rising. A number of surgical treatment options are available, but clinical long-term data are lacking., Methods: This review is based on pertinent publications and guidelines retrieved by a selective literature search, and on the authors' clinical experience., Results: Patients often report one or more relatively trivial traumatic incidents leading up to the fracture. They complain of pain in the hip, groin, or lower lumbar region, or of low back pain and sciatica. A new classification scheme entitled Fragility Fractures of the Pelvis (FFP) takes the morphology of the fracture into account and can be used as an aid to therapeutic decision-making (evidence level IV). The goal of treatment is early mobilization with adequate pain relief. Isolated anterior pelvic ring fractures (FFP I) and nondisplaced posterior pelvic ring fractures (FFP II) are usually stable and can be treated conservatively. Type III and IV injuries are unstable and should generally be treated surgically., Conclusion: Retrospective analyses have shown that osteoporotic pelvic fractures are associated with decreased mobility and independence and with a one-year mortality ranging from 9.5% to 27%. Prospective therapeutic trials are urgently needed.

Deformation of the spine following vertebral compression fracture (VCF) can be associated with severe spinal dysfunction. Anatomical restoration is described as the complete reduction and stable fixation of the fracture with the goal to restore the pre-fracture local and global spine properties. The essential need to obtain endplate reduction, and consider the whole vertebral body in the management of vertebral fractures is pointed out. A new 3D imaging technique is described. A new assessment method based on CT scans 3D reconstructions was developed. This new method was used to assess the anatomical restoration of the fractured vertebrae. A procedure consisting in placing two expandable titanium implants for fracture reduction, together with stabilization with a high viscosity PMMA cement was used to demonstrate the method. The cases presented here are demonstrating that this 3D-mapping software is a tool which can address the lack of a valid, reproducible and user-friendly method to evaluate the anatomical restoration in VCF. The evaluation of the anatomical restoration of the fractured vertebrae raises some issues in terms of interpretation because of a lack of consensus in the existing reporting methods. A 3D-reconstruction method, using CT scans and a newly-developed software, is proposed to evaluate the anatomical restoration in a clear, valid, reproducible and user-friendly way.

Object: The treatment of traumatic burst fractures unaccompanied by neurological impairment remains controversial and ranges from conservative management to 360° fusion. Because of the heterogeneity of fracture types, classification systems, and treatment options, comparative biomechanical studies might help to improve our knowledge. The aim of the current study was to create a standardized fracture model to investigate burst fractures in a multisegmental setting., Methods: A total of 28 thoracolumbar fresh-frozen human cadaveric spines were used. The spines were dissected into segments (T11-L3). The T-11 and L-3 vertebral bodies were embedded in Technovit 3040 (cold-curing resin for surface testing and impressions). To simulate high energy, a metallic drop tower was designed. Stress risers were used to ensure comparable fractures. CT scans were acquired before and after fracture. All fractures were classified using the AO/OTA classification., Results: The preparation and embedding of the spine segments worked well. No repositioning or second embedding of the specimen, even after fracture, was required. It was possible to create single burst fractures at the L-1 level in all 28 spine segments. Among the 28 fractures there were 16 incomplete burst fractures (Type A3.1), 8 burst-split fractures (Type A3.2), and 4 complete burst fractures (Type A3.3). The differences before and after fracture for stiffness and for anterior, posterior, and central heights were all significant (p < 0.05)., Conclusions: The ability to create reproducible burst fractures of a single vertebral body in a thoracolumbar spine segment may serve as a basis for future biomechanical studies that will provide better understanding of mechanical properties or fixation techniques.

Background: The incidence of osteoporotic and insufficiency fractures of the pelvic ring is increasing. Closed reduction and percutaneous fixation with cannulated sacroiliac screws is well-established in the operative treatment of osteoporotic posterior pelvic ring fractures. However, osteoporotic bone quality might lead to the risk of screw loosening. For this reason, cement augmentation of the iliosacral screws is more frequently performed and recommended., Purpose: The aim of the present biomechanical study was to evaluate the primary stability of three methods of iliosacral screw fixation in human osteoporotic sacrum specimens., Study Design/setting: This study used methodical cadaver study., Methods: A total of 15 fresh frozen human cadaveric specimens with osteoporosis were used (os sacrum). After matched pair randomization regarding bone quality (T-score), three operation technique groups were generated: screw fixation (cannulated screws) without cement augmentation (Group A); screw fixation with cement augmentation before screw placement (cannulated screws) (Group B); and screw fixation with perforated screws and cement augmentation after screw placement (Group C). In all specimens both sides of the os sacrum were used for operative treatment, resulting in a group size of 10 specimens per group. One operation technique was used on each side of the sacral bone to compare biomechanical properties in the same bone quality. Pull-out tests were performed with a rate of 6 mm/min. A load versus displacement curve was generated., Results: Subgroup 1 (Group A vs. Group B): Screw fixation without cement augmentation: 594.4 N±463.7 and screw fixation with cement augmentation before screw placement: 1,020.8 N±333.3; values were significantly different (p=.025). Subgroup 2 (Group A vs. Group C): Screw fixation without cement augmentation: 641.8 N±242.0 and perforated screw fixation with cement augmentation after screw placement: 1,029.6 N±326.5; values were significantly different (p=.048). Subgroup 3 (Group B vs. Group C): Screw fixation with cement augmentation before screw placement: 804.0 N±515.3 and perforated screw fixation with cement augmentation after screw placement: 889.8 N±503.3; values were not significantly different (p=.472)., Conclusions: Regarding iliosacral screw fixation in osteoporotic bone, the primary stability of techniques involving cement augmentation is significantly higher compared with screw fixation without cement augmentation. Perforated screws with the same primary stability as that of conventional screw fixation in combination with cement augmentation might be a promising alternative in reducing complications of cement leakage. These biomechanical results have to be transferred into clinical practice and prove their clinical value., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: To evaluate the efficacy, feasibility and safety of a percutaneous anatomical vertebral body reduction for the treatment of VCF (vertebral compression fracture) linked to malignancy. Vertebroplasty and percutaneous kyphoplasty have played essential roles in the treatment of painful vertebral metastasis, although there are few reports with long survival that have evaluated the long-term efficacy, adjacent fractures and vertebral body (VB) re-collapse associated with these procedures. We aimed to evaluate the longterm efficacy and the complications associated with malignancy and changes in spinal biomechanics., Material and Methods: The retrospective study examined 32 patients with osteolytic VCF due to malignant infiltration of the vertebral body. A visual analogue scale, the EQ5 and radiological analysis (i.e., X-ray and CT scan) were used to assess back pain, quality of life and complications., Results: Statistically significant reductions in anterior and central vertebral body heights (6.2 mm-19.6 ± 4.2 mm- and 5.8 mm- 16.7 ± 7.8 mm-, respectively) that resulted in reductions of the regional Cobb angles exceeding 30% were observed. There was also a statistically significant improvement in quality of life. The average survival was longer than those reported in most published articles, and the average follow-up period was 30.9 months., Conclusion: Anatomical restoration (i.e., cortical ring reduction with endplate rebalancing) is potentially beneficial for a wellselected group of patients with spine metastases and long life expectancies because this procedure avoids the complications typical of these types of treatments (e.g., leakage, adjacent fractures and re-collapse).

Background: The treatment of osteoporotic vertebral compression fractures using transpedicular cement augmentation has grown significantly during the past two decades. Balloon kyphoplasty was developed to restore vertebral height and improve sagittal alignment. Several studies have shown these theoretical improvements cannot be transferred universally to the clinical setting., Purpose: The aim of the current study is to evaluate two different procedures used for percutaneous augmentation of vertebral compression fractures with respect to height restoration: balloon kyphoplasty and SpineJack., Materials and Methods: Twenty-four vertebral bodies of two intact, fresh human cadaveric spines (T6-L5; donor age, 70 years and 60 years; T-score -6.8 points and -6.3 points) were scanned using computed tomography (CT) and dissected into single vertebral bodies. Vertebral wedge compression fractures were created by a material testing machine (Universal testing machine, Instron 5566, Darmstadt, Germany). The axial load was increased continuously until the height of the anterior edge of the vertebral body was reduced by 40% of the initial measured values. After 15 minutes, the load was decreased manually to 100 N. After postfracture CT, the clamped vertebral bodies were placed in a custom-made loading frame with a preload of 100 N. Twelve vertebral bodies were treated using SpineJack (SJ; Vexim, Balma, France), the 12 remaining vertebral bodies were treated with balloon kyphoplasty (BKP; Kyphon, Medtronic, Sunnyvale, CA, USA). The load was maintained during the procedure until the cement set completely. Posttreatment CT was performed. Anterior, central, and posterior height as well as the Beck index were measured prefracture and postfracture as well as after treatment., Results: For anterior height restoration (BKP, 0.14±1.48 mm; SJ, 3.34±1.19 mm), central height restoration (BKP, 0.91±1.04 mm; SJ, 3.24±1.22 mm), and posterior restoration (BKP, 0.37±0.57 mm; SJ, 1.26±1.05), as well as the Beck index (BKP, 0.00±0.06 mm; SJ, 0.10±0.06), the values for the SpineJack group were significantly higher (p<.05) CONCLUSION: The protocols for creating wedge fractures and using the instrumentation under a constant preload of 100 N led to reproducible results and effects. The study showed that height restoration was significantly better in the SpineJack group compared with the balloon kyphoplasty group. The clinical implications include a better restoration of the sagittal balance of the spine and a reduction of the kyphotic deformity, which may relate to clinical outcome and the biological healing process., (Copyright © 2015 Elsevier Inc. All rights reserved.)

This prospective, consecutive, multicentre observational registry aimed to confirm the safety and clinical performance of the SpineJack system for the treatment of vertebral compression fractures (VCF) of traumatic origin. We enrolled 103 patients (median age: 61.6 years) with 108 VCF due to trauma, or traumatic VCF with associated osteoporosis. Primary outcome was back pain intensity (VAS). Secondary outcomes were Oswestry Disability Index (ODI), EuroQol-VAS, and analgesic consumption. 48 hours after surgery, a median relative decrease in pain intensity of 81.5% was observed associated with a significant reduction in analgesic intake. Improvements in disability (91.3% decrease in ODI score) and in quality of life (increase 21.1% of EQ-VAS score) were obtained 3 months after surgery. All results were maintained at 12 months. A reduction in the kyphotic angulation was observed postoperatively (-5.4 ± 6.3°; p < 0.001), remained at 12 months (-4.4 ± 6.0°, p = 0.002). No adverse events were implant-related and none required device removal. Three patients (2.9%) experienced procedure-related complications. The overall adjacent fracture rate up to 1 year after surgery was 2.9%. The SpineJack procedure is an effective, low-risk procedure for patients with traumatic VCF allowing a fast and sustained improvement in quality of life over 1 year after surgery.

Purpose: The treatment of vertebral burst fractures is still controversial. The aim of the study is to evaluate the purpose of additional percutaneous intravertebral reduction when combined with dorsal instrumentation., Methods: In this biomechanical cadaver study twenty-eight spine segments (T11-L3) were used (male donors, mean age 64.9 ± 6.5 years). Burst fractures of L1 were generated using a standardised protocol. After fracture all spines were allocated to four similar groups and randomised according to surgical techniques (posterior instrumentation; posterior instrumentation + intravertebral reduction device + cement augmentation; posterior instrumentation + intravertebral reduction device without cement; and intravertebral reduction device + cement augmentation). After treatment, 100000 cycles (100-600 N, 3 Hz) were applied using a servohydraulic loading frame., Results: Overall anatomical restoration was better in all groups where the intravertebral reduction device was used (p < 0.05). In particular, it was possible to restore central endplates (p > 0.05). All techniques decreased narrowing of the spinal canal. After loading, clearance could be maintained in all groups fitted with the intravertebral reduction device. Narrowing increased in the group treated with dorsal instrumentation., Conclusions: For height and anatomical restoration, the combination of an intravertebral reduction device with dorsal instrumentation showed significantly better results than sole dorsal instrumentation.

The purpose of this prospective multicentric observational study was to confirm the safety and clinical performance of a craniocaudal expandable implant used in combination with high viscosity PMMA bone cement for the treatment of vertebral compression fractures. Thirty-nine VCFs in 32 patients were treated using the SpineJack minimally invasive surgery protocol. Outcome was determined by using the Visual Analogue Scale for measuring pain, the Oswestry Disability Index for scoring functional capacity, and the self-reporting European Quality of Life scores for the quality of life. Safety was evaluated by reporting all adverse events. The occurrence of cement leakages was assessed by either radiographs or CT scan or both. Statistically significant improvements were found regarding pain, function, and quality of life. The global pain score reduction at 1 year was 80.9% compared to the preoperative situation and the result of the Oswestry Disability Index showed a decrease from 65.0% at baseline to 10.5% at 12 months postoperatively. The cement leakage rate was 30.8%. No device- or surgery-related complications were found. This observational study demonstrates promising and persistent results consisting of immediate and sustained pain relief and durable clinical improvement after the procedure and throughout the 1-year follow-up period.

Background Context: Thoracolumbar extension-distraction fractures are rare injuries mainly restricted to patients suffering from ankylosing spinal disorders. The most appropriate surgical treatment of these unstable spinal injuries remains to be clarified., Purpose: To report on a cohort of 10 patients treated with closed reduction and percutaneous dorsal instrumentation., Study Design: Case series., Patient Sample: Ten consecutive patients with ankylosing spinal disorders and thoracolumbar extension-distraction fractures (Type B3 according to the AOSpine Thoracolumbar Spine Injury Classification System)., Outcome Measures: Postoperative reduction, alignment, and implant position were analyzed by computed tomography. Loss of reduction was assessed on lateral radiographs by using the Cobb technique. Ambulation ability and pain were assessed at follow-up., Methods: Minimally invasive dorsal percutaneous instrumentation was performed in 10 consecutive patients (3 men, 7 women) with a mean age of 81.5 (range 72-90) years between May 2010 and December 2012. The mean postoperative follow-up time was 7.9 (range 4-28) months., Results: All 10 patients were treated with closed reduction and dorsal instrumentation; in no case was conversion to an open approach required. The mean operation time was 60.2 (range 32-135) minutes. None of the patients presented neurologic deficits. Cement-augmented screws were implanted in two cases. Sufficient radiographic correction was achieved in all patients; no case of loss of reduction was noted at final follow-up. In one case, complete hardware removal was performed 9 months after the index operation because of persistent back pain at the level of the implant. One patient died of postoperative inferior vena cava obstruction. At discharge, all patients were able to ambulate without the need for crutches or opioid analgesics. At final follow-up, all patients ambulated with full weight bearing; four patients reported persistent back pain., Conclusions: In fragile patients with ankylosing spinal disorders and thoracolumbar extension-distraction fractures, closed reduction and percutaneous dorsal instrumentation provide a satisfying midterm functional outcome while minimizing perioperative risks compared with conventional dorsoventral procedures., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: The aim of this cadaveric study was to compare a polyaxial (NCB®, Zimmer) to a fixed-angle monoaxial locking plate (PERILOC®, Smith & Nephew) in comminuted fractures of the distal femur regarding stability of the construct. Up to date there is no published biomechanical data concerning polyaxial plating in cadaveric distal femurs., Methods: Fourteen formalin fixed femora were scanned by dual-energy x-ray absorptiometry. As fracture model an unstable supracondylar comminuted fracture was simulated. Fractures were pairwise randomly fixed either with a mono- (group A) or a polyaxial (group B) distal femur plate. The samples were tested in a servohydraulic mechanical testing system starting with an axial loading of 200 N following an increase of 200 N in every step with 500 cycles in every sequence up to a maximum of 2 000 N. The end points were implant failure or relevant loss of reduction. Data records included for each specimen time, number of cycles, axial load and axial displacement. Statistical analysis was performed using the exact Wilcoxon signed rank test., Results: The mean donor age at the time of death was 75 years. The bone mass density (BMD) of the femurs in both groups was comparable and showed no statistically significant differences. Five bones failed before reaching the maximum applied force of 2000 N. Distribution curves of all samples in both groups, showing the plastic deformation in relation to the axial force, showed no statistically significant differences., Conclusions: Operative stabilization of distal femur fractures can be successfully and equally well achieved using either a monoaxial or a polyaxial locking plate. Polyaxial screw fixation may have advantages if intramedullary implants are present.

Object: Injuries of the subaxial cervical spine including facet joints and posterior ligaments are common. Potential surgical treatments consist of anterior, posterior, or anterior-posterior fixation. Because each approach has its advantages and disadvantages, the best treatment is debated. This biomechanical cadaver study compared the effect of different facet joint injuries on primary stability following anterior plate fixation., Methods: Fractures and plate fixation were performed on 15 fresh-frozen intact cervical spines (C3-T1). To simulate a translation-rotation injury in all groups, complete ligament rupture and facet dislocation were simulated by dissecting the entire posterior and anterior ligament complex between C-4 and C-5. In the first group, the facet joints were left intact. In the second group, one facet joint between C-4 and C-5 was removed and the other side was left intact. In the third group, both facet joints between C-4 and C-5 were removed. The authors next performed single-level anterior discectomy and interbody grafting using bone material from the respective thoracic vertebral bodies. An anterior cervical locking plate was used for fixation. Continuous loading was performed using a servohydraulic test bench at 2 N/sec. The mean load failure was measured when the implant failed., Results: In the group in which both facet joints were intact, the mean load failure was 174.6 ± 46.93 N. The mean load failure in the second group where only one facet joint was removed was 127.8 ± 22.83 N. In the group in which both facet joints were removed, the mean load failure was 73.42 ± 32.51 N. There was a significant difference between the first group (both facet joints intact) and the third group (both facet joints removed) (p < 0.05, Kruskal-Wallis test)., Conclusions: In this cadaver study, primary stability of anterior plate fixation for dislocation injuries of the subaxial cervical spine was dependent on the presence of the facet joints. If the bone in one or both facet joints is damaged in the clinical setting, anterior plate fixation in combination with bone grafting might not provide sufficient stabilization; additional posterior stabilization may be needed.

Background: Penetrating arterial injuries to the limbs are common injuries in high volume trauma centers. Their overall surgical results reported in the literature are satisfactory - apart of those of the popliteal artery that still may lead to a significant incidence in amputations. With the present study we assessed our outcome with penetrating arterial injuries to the limb as to see if the direct involvement of vascular surgeons in the management of popliteal artery injuries leads to an improved (lowered) amputation rate. Results were benchmarked with our published results from previous years., Methods: All patients sustaining penetrating arterial injuries to the limbs admitted to the Chris Hani Baragwanath Academic Hospital during an 18- month period ending in September 2011 were included in this study. Axillary, brachial and femoral artery injuries were operated on by the trauma surgeons as in the past. All popliteal artery injuries were operated on by the vascular surgeons (new)., Results: There were a total of 113 patients with 116 injuries, as some patients had multiple vascular injuries: 10 axillary, 47 brachial, 34 femoral and 25 popliteal artery injuries. Outcome of axillary, brachial and femoral artery injury repair were excellent and not significantly different from our previous reported experience. Injury to the popliteal artery showed a diminished re-exploration rate from 34% down to 10% (p = 0,049) and a decrease of amputation rate from 16% to 11% which was statistically not significant (p = 0,8)., Conclusion: Penetrating arterial trauma to the axillary, brachial and femoral artery is followed by excellent results when operated by trauma surgeons. In the case of popliteal artery injury operated by the vascular surgeons, the results of this study do not show any statistically significant difference related to amputation rate from our previous reported studies when operated by trauma surgeons. Taking into consideration the diminished re-exploration rate and a tendency to a lower amputation rate, we feel that there is possible tendency of better outcome if operated by vascular surgeons. Multicenter studies with large number of enrolled patients will be required to prove the validity of this suggestion.

Background: Two different procedures, used for percutaneous augmentation of vertebral compression fractures were compared, with respect to height restoration and maintenance after cyclic loading. Additionally the impact of the cement volume used was investigated., Methods: Wedge compression fractures were created in 36 human cadavaric vertebrae (T10-L3). Twenty-seven vertebrae were treated with the SpineJack® with different cement volumes (maximum, intermediate, and no cement), and 9 vertebrae were treated with Balloon Kyphoplasty. Vertebral heights were measured pre- and postfracture as well as after treatment and loading. Cyclic loading was performed with 10,000cycles (1Hz, 100-600N)., Findings: The average anterior height after restoration was 85.56% for Kyphoplasty; 96.20% for SpineJack® no cement; 93.44% for SpineJack® maximum and 96% for the SpineJack® intermediate group. The average central height after restoration was 93.89% for Kyphoplasty; 100.20% for SpineJack® no cement; 99.56% for SpineJack® maximum and 101.13% for the SpineJack® intermediate group. The average anterior height after cyclic loading was 85.33 % for Kyphoplasty; 87.30% in the SpineJack® no cement, 92% in the SpineJack® maximum and 87% in the SpineJack® intermediate group. The average central height after cyclic loading was 92% for Kyphoplasty; 93.80% in the SpineJack® no cement; 98.56% in the SpineJack® maximum and 94.25% in the SpineJack® intermediate group., Interpretation: Height restoration was significantly better for the SpineJack® group compared to Kyphoplasty. Height maintenance was dependent on the cement volume used. The group with the SpineJack® without cement nevertheless showed better results in height maintenance, yet the statistical significance could not be demonstrated., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Introduction: Occipital condyle fractures (OCFs) are considered to be rare injuries. OCFs are now diagnosed more often because of the widespread use of computed tomography. Our aim is to report the incidence, treatment and long term outcome of 8 patients with OCFs., Materials and Methods: All patients presenting with multiple trauma from 1993 to 2006 were analyzed retrospectively. Characteristics and course of the treatment were evaluated. Follow-up was performed after 11,7 years (range 5,9 to 19,3 years)., Results: Nine cases of OCF in 8 patients were identified. All injuries resulted from high velocity trauma. The average scores on the ISS Scale were 39,6 (24-75) and 7,3 (3-15) on the GCS. According to Anderson's classification, 5 cases of Type III and 4 cases of Type I fractures were identified. According to Tuli's classification, 5 cases of Type IIA and 4 cases of Type I were found. Indications for immobilization with the halo-vest were type III injuries according to Anderson's classification or Tuli's type IIA injuries, respectively. Patients with Tuli's type I injuries were treated with a Philadelphia collar for 6 weeks. In one patient with initial complete tetraplegia and one with incomplete neurological deficits the final follow-up neurologic examination showed no neurological impairment at all (Frankel-grade A to E, respectively B to E). At follow-up, 3 patients were asymptomatic. Four patients suffered from mild pain when turning their head, pain medication was necessary in one case only., Discussion: OCF's are virtually undetectable using conventional radiography. In cases of high velocity, cranio-cervical trauma or impaired consciousness, high resolution CT-scans of the craniocervical junction must be performed. We suggest immobilization using a halo device for type III injuries according to Anderson's classification or Tuli's type IIa injuries, respectively. Patients with Tuli's type I injuries should be treated with a Philadelphia collar.

Object: For many type II fractures of the dens (Anderson and D'Alonzo classification), a double anterior screw fixation is performed. If screw disruption occurs, the location is most often at the anterior caudal endplate and body of the axis and not directly at the fracture line. The authors' objective was to determine the differences in primary mechanical stability at 2 insertion points used in ventral screw fixation of type II fractures of the C-2 dens., Methods: Screw fixation was performed on 16 formalin-fixed human C-2 dens specimens. The specimens were divided into 2 groups. For group 1, the screws were inserted directly at the anterior lower endplates; for group 2, the screws were inserted 2 mm dorsal to the anterior wall of the vertebral body. After a type II odontoid fracture was created with an oscillating saw, screw fixation was performed using two 3.5-mm partially threaded lag screws with washers. Subsequently, each vertebral body was continuously loaded. The criterion for breakage was reversal of the force vector., Results: In group 1, screw disruption occurred at the point of entry; the mean load failure was 290.5 ± 106 N. In group 2, no screw disruption occurred; the mean load failure was 574.2 ± 170.5 N. These results were significant (p < 0.05)., Conclusions: For double screw fixation of type II fractures of the dens (Anderson and D'Alonzo classification), placement of the screws as far dorsal to the anterior lower endplate as possible seems to favorably affect primary stability. In actual clinical practice, care should be taken to not damage the anterior wall of the vertebral body of the axis during screw insertion.

Brain plasticity as a neurobiological reflection of individuality is difficult to capture in animal models. Inspired by behavioral-genetic investigations of human monozygotic twins reared together, we obtained dense longitudinal activity data on 40 inbred mice living in one large enriched environment. The exploratory activity of the mice diverged over time, resulting in increasing individual differences with advancing age. Individual differences in cumulative roaming entropy, indicating the active coverage of territory, correlated positively with individual differences in adult hippocampal neurogenesis. Our results show that factors unfolding or emerging during development contribute to individual differences in structural brain plasticity and behavior. The paradigm introduced here serves as an animal model for identifying mechanisms of plasticity underlying nonshared environmental contributions to individual differences in behavior.

Background: A great variety of methods for the stabilisation of periprosthetic fractures around total hip (THA) or total knee arthroplasty (TKA) have been described. We present the data of our experience in combining a polyaxial, anatomical locking plate with a standardised less invasive technique in the treatment of periprosthetic and peri-implant (femoral nail) femur fractures in this prospective study., Patients and Methods: A consecutive series of 41 patients (33 women; age 79.8±11 years) with 41 fractures (n=17 periprosthetic THA, n=10 periprosthetic TKA, n=3 interprosthetic, n=11 perinail) was treated in a 'mini-open' (MO; direct reduction of the fracture and percutaneous plate fixation in two-part fractures; n=22) or a 'minimally invasive' (MI; indirect reduction and percutaneous fixation; n=19) technique. All patients were followed up for 12 months postoperatively., Results: The polyaxial locking mechanism allowed for the setting of a mean of 5.3 screws around an intramedullary implant. Supported by the less invasive strategy, mainly long plates (n=36; 88% were longer than 24cm) were applied without relevant soft-tissue complication. Five surgical revisions (12.1%) had to be performed. During the first postoperative stay, one seroma was evacuated and in two cases the plate broke due to failed biological healing 6 months after the MO technique. In one case, a revision prosthesis had to be implanted due to ligamentous instability, and in another case, soft-tissue balancing of the patella was performed. In the MO group, four of the five complications requiring surgical revision were seen. There was no infection. No statistical difference was seen between the MO and the MI groups for operating room (OR) time and perioperative need for transfusion. In patients with a poor state of health (n=8; immobile and Glasgow Coma Outcome Scale=3), no local complications were seen. All fractures in the peri-implant fracture group (n=11) healed uneventfully., Conclusion: Periprosthetic fracture fixation can be performed as part of a standardised less invasive strategy, but the MI technique should be the preferred treatment. The NCB(®) system allows for a stable plate fixation around an intramedullary implant. With the less invasive technique, long plates can be applied with low rates of soft-tissue complication and implant failure., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Background: The treatment of painful osteoporotic vertebral compression fractures with transpedicular cement augmentation has grown significantly over the last 20 years. There is still uncertainty about long-term and midterm effects of polymethyl methacrylate in trabecular bone. Preservation of the trabecular structures, as well as interdigitation of the cement with the surrounding bone, therefore has been gaining increasing attention. Interdigitation of cement is likely relevant for biological healing and the biomechanical augmentation process. In this study a cutting and grinding technique was used to evaluate the interdigitation for 4 augmentation techniques., Methods: By use of a standardized protocol, wedge fractures were created in vertebrae taken from a fresh-frozen spine. Thereafter the vertebrae were assigned to 1 of 4 similar groups with regard to the vertebral size and force required to produce the fracture. The 4 groups were randomized to the following augmentation techniques: balloon kyphoplasty, radiofrequency (RF) kyphoplasty, shield kyphoplasty, and vertebral stenting. Histologic analysis was designed to examine the bone structure and interdigitation after the augmentation., Results: For the void-creating procedures, the distance between bone and cement was 341.4 ± 173.7 µm and 413.6 ± 167.6 µm for vertebral stenting and balloon kyphoplasty, respectively. Specifically, the trabecular bone was condensed around the cement, forming a shield of condensed bone. The procedures without a balloon resulted in shorter distances of 151.2 ± 111.4 µm and 228.1 ± 183.6 µm for RF and shield kyphoplasty, respectively. The difference among the groups was highly significant (P < .0001). The percentage of interdigitation was higher for the procedures that did not use a balloon: 16.7% ± 9.7% for balloon kyphoplasty, 20.5% ± 12.9% for vertebral stenting, 66.45% ± 12.35% for RF kyphoplasty, and 48.61% ± 20.56% for shield kyphoplasty. The difference among the groups was highly significant (P < .00001)., Conclusions: Cavity-creating procedures reduce the cement interdigitation significantly and may accordingly reduce the effectiveness of the augmentation procedures.

Open posterior instrumentation is still the standard procedure for unstable traumatic thoracic and lumbar fractures. There is a general tendency towards minimally invasive approaches in various surgical disciplines. The Sextant II Rod Insertion system is one of these. The authors prospectively studied this system in 51 patients with thoracic and lumbar fractures, between October 2007 and January 2011. Most fractures (31/51) were situated at the lumbar level. In 7 older patients the technique was combined with kyphoplasty and/or cement augmentation of the pedicle screws. The median operative time was 61 minutes (range: 26-130). The median fluoroscopy time was 132 seconds (range: 24-414). Most pedicle screws were correctly placed: 197 out of 204 screws. All fractures showed bony union after 6 weeks, but the multiaxial pedicle screws were not able to conserve the slight correction obtained peroperatively via positioning and longitudinal traction. Percutaneous minimally invasive stabilization of the spine needs further improvement.

The treatment of painful osteoporotic vertebral compression fractures using transpedicular cement augmentation has grown significantly over the last two decades. The benefits of balloon kyphoplasty compared to conservative treatment remain controversial and are discussed in the literature. The complication rates of vertebroplasty and kyphoplasty are considered to be low. The focus of this study was the analysis of acute and clinically relevant complications related to this procedure. In our department, all patients treated between February 2002 and February 2011 with percutaneous cement augmentation (372 patients, 522 augmented vertebral bodies) were prospectively recorded. Demographic data, comorbidities, fracture types, intraoperative data and all complications were documented. The pre- and postoperative pain-level and neurological status (Frankel-Score) were evaluated. All patients underwent a standardized surgical procedure. Two hundred and ninety-seven patients were treated solely by balloon kyphoplasty; 216 females (72.7%) and 81 males (27.3%). Average patient age was 76.21 years (±10.71, range 35-98 years). Average American Society Anestesiologists score was 3.02. According to the Orthopedic Trauma Association classification, there were 69 A 1.1 fractures, 177 A 1.2 fractures, 178 A 3.1.1 fractures and 3 A 3.1.3 fractures. Complications were divided into preoperative, intraoperative and postoperative events. There were 4 preoperative complications: 3 patients experienced persistent pain after the procedure. In one case, the pedicles could not be visualized during the procedure and the surgery was terminated. One hundred and twenty-nine (40.06%) of the patients showed intraoperative cement leaking outside the vertebras, one severe hypotension and tachycardia as reaction to the inflation of the balloons, and there was one cardiac arrest during surgery. Postoperative subcutaneous hematomas were observed in 3 cases, 13 patients developed a urinary tract infection, and 2 patients died during hospitalization. Twenty-four patients (8.1%) returned because of new pain events and 23 patients reported a new painful fracture. Balloon kyphoplasty is a save and effective procedure to treat patients with painful vertebral compression fractures. Rapid patient mobilization after kyphoplasty, as well as a prompt reintegration into the social environment, are possible. Compared to other surgical procedures, especially in patients with an average age of 75 years, balloon kyphoplasty seems to offer some advantages. However, the procedure still has a potential for serious complications and should be performed by well trained personnel.

Objective: The development of locking plate systems has led to polyaxial screws and new plate designs. This study compares monoaxial head locking screws (PHILOS© by Synthes) and a new generation of polyaxial locking screws (NCB-LE© by Zimmer) with respect to biomechanical stability., Methods: On nine pairs of randomised formalin fixed humerus specimens, standardised osteotomies and osteosyntheses with nine monoaxial (group A) und nine polyaxial (group B) plate/screw systems were performed. A material testing machine by Instron (M-10 14961-DE) was used for cyclic stress tests and crash tests until defined breakup criteria as endpoints were reached., Results: After axial cyclic stress 200 times at 90 N, plastic deformation was 1.02 mm in group A and 1.25 mm in group B. After the next cycle using 180 N the additional deformation averaged 0.23 mm in group A and 0.39 mm in group B. The deformation using 450 N was 0.72 mm in group A compared to 0.92 mm in group B. The final full power test resulted in a deformation average of 0.49 mm in group A and 0.63 mm in group B after 2,000 cycles using 450 N. When reaching the breakup criteria the plastic deformation of the NCB plate was 9.04 mm on average. The PHILOS plate was similarly deformed by 9.00 mm. As a result of the crash test, in group A the screws pulled out of the humeral head four times whereas the shaft broke one time and another time the implant was ripped out. The gap was closed four times. In group B, there were three cases of screw cut-through, four shaft fractures/screw avulsions from the shaft and two cases of gap closure., Conclusion: The two systems resist the cyclic duration tests and the increasing force tests in a similar manner. The considerable clinical benefits of the polyaxial system are enhanced by equal biomechanical performance.

Kyphoplasty has become a standard procedure in the treatment of painful osteoporotic compression fractures. According to current guidelines, involvement of the posterior wall of the vertebral body is a relative contraindication. From February 2002 until January 2008, 97 patients with at least one AO classification A 3.1 fracture were treated by kyphoplasty. There was a structured follow-up for the medium-term evaluation of the patients' outcome. Ninety-seven patients (68 of whom were females and 29 of whom were males) with involvement of the vertebra's posterior margin averaging 76.1 +/- 12.36 (59-98) years were treated by kyphoplasty. The fractures of 75 patients were caused by falls from little height, 5 patients had suffered traffic accidents and in the case of 17 patients, no type of trauma was remembered. According to the AO classification, there were 109 A 3.1.1 and one A3.1.3 injuries. Prior to surgery, all patients were neurologically without pathological findings. Seventy-nine fractures were accompanied by a narrowing of the spinal canal [average of 15% (10-40)]. Overall, 134 vertebras were treated by Balloon kyphoplasty (81 x 1 segment, 22 x 2 segments, 3 x 3 segments). In 47.4% of the patients, cement leakage was observed after surgery. All patients with cement extravasation, however, were clinically unremarkable. Using the visual analog scale, patients stated that prior to surgery their pain averaged 8.1, whereas after surgery it significantly decreased and averaged 1.6 (p < 0.001). In geriatric patients with osteoporotic vertebral fractures with partial inclusion of the posterior wall of the vertebral body, kyphoplasty is an effective procedure with few complications.

We assessed age-related differences in adults in familiarization to treadmill walking within virtual environments (VE), and examined whether treadmill walking after familiarization resembles overground walking. Seventeen younger and 17 older adults walked at preferred speed on an overground walkway and afterwards walked at the same speed for 20 min on a treadmill coupled to a VE. A motion capture system was used to measure spatio-temporal gait parameters. On the treadmill, both younger and older adults initially displayed decreased step length and increased step width, cadence, and time in double support relative to overground walking. Except for time in double support, step characteristics approached overground walking-behavior with a negatively accelerated trend. After 15 min of treadmill walking, changes became minor corresponding to less than 1% deviations to individuals' overground walking. At the end of familiarization, average differences in step length, cadence, and double support relative to overground walking were reduced to less than 5 percent in both age groups. For step width, younger adults approximated overground walking after 20 min more closely than older adults, probably reflecting larger initial differences between treadmill and overground walking among older adults. We conclude (a) that 20 min of familiarization to treadmill walking in a VE are sufficient to reach stable walking patterns resembling those observed in overground walking, but that some differences between the two settings remain, especially in older adults; (b) that sufficient familiarization to the treadmill is needed to ascertain the validity and generalizability of comparisons between younger and older adults., (Copyright 2009 Elsevier B.V. All rights reserved.)

Impacts of individual behavior on personal exposure to particulate matter (PM) and the associated individual health effects are still not well understood. As outdoor PM concentrations exhibit highly temporal and spatial variations, personal PM exposure depends strongly on individual trajectories and activities. Furthermore, indoor environments deserve special attention due to the large fraction of the day people spend indoors. The indoor PM concentration in turn depends on infiltrated outdoor PM and indoor particle sources, partially caused by the activities of people indoor. We present an approach to estimate PM2.5 exposure levels for individuals based upon existing data sources and models. For this pilot study, six persons kept 24-hour diaries and GPS tracks for at least one working day and one weekend day, providing their daily activity profiles and the associated geographical locations. The survey took place in the city of Münster, Germany in the winter period between October 2006 and January 2007. Environmental PM2.5 exposure was estimated by using two different models for outdoor and indoor concentrations, respectively. For the outdoor distribution, a dispersion model was used and extended by actual ambient fixed site measurements. Indoor concentrations were modeled using a simple mass balance model with the estimated outdoor concentration fraction infiltrated and indoor activities estimated from the diaries. A limited number of three 24-hour indoor measurements series for PM were performed to test the model performance. The resulting average daily exposure of the 14 collected profiles ranged from 21 to 198 microg m(-3) and showed a high variability over the day as affected by personal behavior. Due to the large contribution of indoor particle sources, the mean 24-hour exposure was in most cases higher than the daily means of the respective outdoor fixed site monitors. This feasibility study is a first step towards a more comprehensive modeling approach for personal exposure, and therefore restricted to limited data resources. In future, this model framework not only could be of use for epidemiological research, but also of public interest. Any individual operating a GPS capable device may become able to obtain an estimate of its personal exposure along its trajectory in time and space. This could provide individuals a new insight into the influence of personal habits on their exposure to air pollution and may result in the adaptation of personal behavior to minimize risks.

Neurodegenerative disorders such as Alzheimer's disease (AD) are increasingly threatening public health. Most animal models of AD consist of transgenic mice that are usually housed singly or in unisexual groups in small barren cages. Such restricted environments, however, prevent the mice from showing a variety of species-specific behaviors and consequently may constrain comprehensive behavioral phenotyping. On the other hand, allowing the animals to freely organize their lives in a spacious physically and socially enriched environment makes behavioral phenotyping laborious and time consuming. Radio frequency identification (RFID) using a network of antennae and small glass-coated transponders labeling each individual allows for gathering spatiotemporal information about a large number of individuals in parallel. The aim of this project was to use the RFID technique to facilitate the characterization of mice carrying a genetic disposition to develop AD-like pathology and of their wild-type conspecifics in a spacious seminaturalistic environment.

Study Design: Case report and clinical discussion., Objective: To describe a rare case of vertebral involvement of systemic mastocytosis and its multimodal therapy., Summary of Background Data: Vertebral fractures in young men are rare events. A thorough diagnostic work-up that unravels the underlying cause of osteoporosis and appropriate therapy are crucial to prevent further fractures., Methods: A 36-year-old man was evaluated for severe back pain and was found to suffer from progressive osteoporosis and multiple vertebral fractures. Bone biopsy analysis revealed tryptase-positive mast cells that were positive for c-KIT, thus confirming the diagnosis of systemic mastocytosis., Results: In addition to zoledronic acid (4 mg per month) and prednisolone (50 mg per day) treatment, the patient underwent kyphoplasty. The procedure was associated with arterial hypotension which was most likely because of pressure-induced mast cell degranulation. Follow-up visits demonstrated stable bone mineral density and tolerable back pain while on zoledronic acid., Conclusion: Systemic mastocytosis is a rare cause of vertebral fractures in young men. Because of the potential risk of pressure-induced release of the allergy mediator histamine, kyphoplasty for vertebral involvement of systemic mastocytosis should be conducted with appropriate precautions.

Based on resource-oriented conceptions of successful lifespan development, we propose three principles for evaluating assistive technology: (a) net resource release; (b) person specificity, and (c) proximal versus distal frames of evaluation. We discuss how these general principles can aid the design and evaluation of assistive technology in adulthood and old age, and propose two technological strategies, one targeting sensorimotor and the other cognitive functioning. The sensorimotor strategy aims at releasing cognitive resources such as attention and working memory by reducing the cognitive demands of sensory or sensorimotor aspects of performance. The cognitive strategy attempts to provide adaptive and individualized cuing structures orienting the individual in time and space by providing prompts that connect properties of the environment to the individual's action goals. We argue that intelligent assistive technology continuously adjusts the balance between 'environmental support' and 'self-initiated processing' in person-specific and aging-sensitive ways, leading to enhanced allocation of cognitive resources. Furthermore, intelligent assistive technology may foster the generation of formerly latent cognitive resources by activating developmental reserves (plasticity). We conclude that 'lifespan technology', if co-constructed by behavioral scientists, engineers, and aging individuals, offers great promise for improving both the transition from middle adulthood to old age and the degree of autonomy in old age in present and future generations., (Copyright 2008 S. Karger AG, Basel.)

We examined sex differences in spatial navigation performance using an ecologically relevant experimental paradigm in which virtual maze-like museums are projected in front of a treadmill. Thirty-two 20-30-year-old adults (16 women/16 men) performed a way-finding task in city-block (straight corridors) or variable (irregular corridors) topographies while walking on the treadmill. Sex differences in spatial navigation performance were reduced in variable topographies, suggesting less reliance on spatial relational learning among women. Also, spatial geometric knowledge of the mazes continued to be higher in men after all participants had attained perfect place-finding performance. Results indicate that sex differences in spatial navigation performance are modulated by interactions between environmental demands and sex differences in spatial processing.

This study tests the hypothesis that aging-induced cognitive permeation of sensorimotor functions contributes to adult age differences in spatial navigation performance. Virtual maze-like museums were projected in front of a treadmill. Sixteen 20-30-year-old men and sixteen 60-70-year-old men performed a way-finding task in city-block or variable topographies while walking with or without support. Walking support attenuated age-related decrements in navigational learning. Navigation load increased trunk-angle variability for older adults only. Age differences in spatial knowledge persisted despite perfect place-finding performance. City-block topography was easier than variable topography for younger adults only, indicating age-related differences in reliance on spatial relational learning. Attempts at supporting older adults' navigation performance should consider sensorimotor/cognitive interactions and qualitative differences in navigational activity., ((c) 2006 APA)