Inter-Individual Variability in Postural Control During External Center of Mass Stabilization

Understanding the relation between the motion of the center of mass (COM) and the center of pressure (COP) is important to understand the underlying mechanisms of maintaining body equilibrium. One way to investigate this is to stabilize COM by fixing the joints of the human and looking at the corresponding COP reactions. However, this approach constrains the natural motion of the human. To avoid this shortcoming, we stabilized COM without constraining the joint movements by using an external stabilization method based on inverted cart-pendulum system. Interestingly, this method only stabilized COM of a subgroup of participants and had a destabilizing effect for others which implies significant variability in inter-individual postural control. The aim of this work was to investigate the underlying causes of inter-individual variability by studying the postural parameters of quiet standing before the external stabilization. Eighteen volunteers took part in the experiment where they were standing on an actuated cart for 335 s. In the middle of this period we stabilized their COM in anteroposterior direction for 105 s. To stabilize the COM, we controlled the position of the cart using a double proportional–integral–derivative controller. We recorded COM position throughout the experiment, calculated its velocity, amplitude, and frequency during the quiet standing before the stabilization, and used these parameters as features in hierarchical clustering method. Clustering solution revealed that postural parameters of quiet standing before the stabilization cannot explain the inter-individual variability of postural responses during the external COM stabilization. COM was successfully stabilized for a group of participants but had a destabilizing effect on the others, showing a variability in individual postural control which cannot be explained by postural parameters of quiet-stance.

Evaluation of external stabilization of type II odontoid fractures in geriatric patients—An experimental study on a newly developed cadaveric trauma model

Background Along with the growing geriatric population, the number of odontoid fractures is steadily increasing. However, the effectiveness of immobilizing geriatric odontoid fractures using a cervical collar has been questioned. The aim of the present study is to analyze the physiological and pathological motion in odontoid fractures and to assess limitation of motion in the cervical spine when applying a cervical collar. Methods Motion analysis was performed with wireless motion tracker on unfixed geriatric human cadavers. First, a new geriatric type II odontoid fracture model was developed. In this model, the type II odontoid fracture is operated via a transoral approach. The physiological and pathological flexion and lateral bending of the cervical spine resulting from this procedure was measured. The resulting motion after external stabilization using a cervical collar was analyzed. Results The new geriatric type II odontoid fracture model was successfully established using seven unfixed human cadavers. The pathological flexion of the cervical spine was significantly increased compared to the physiological flexion (p = 0.027). Furthermore, the flexion was significantly reduced when a cervical collar was applied. In case of flexion the mean remaining motion was significantly reduced (p = 0.0017) from 41° to 14°. For lateral bending the mean remaining motion was significantly reduced (p = 0.0137) from 48° to 18°. Conclusions In case of type II odontoid fracture, flexion and lateral bending of the cervical spine are increased due to spinal instability. Thus, if an odontoid fracture is suspected in geriatric patients, the application of a cervical collar should always be considered since external stabilization can significantly reduce flexion and lateral bending.

Comparative analysis between locking compression plate and Joshi's external stabilization system in the management of proximal tibial fractures

<p><strong>Background:</strong> Proximal tibial fractures present with a variety of patterns. They are mostly treated using plate osteosynthesis or Joshi's external stabilization system (JESS) depending upon the injury configuration and surgeon preference. We have compared the efficacy of plate fixation to JESS in the treatment of complex proximal tibial fractures.<strong></strong></p><p><strong>Methods</strong>: 36 patients of proximal tibial fractures with a mean age of 47 years were included in the study, 20 were treated using plate osteosynthesis while the other 16 were treated using JESS, they were followed up at regular intervals till 24 weeks and the progress was recorded in accordance with the knee society score (KSS) parameters<strong></strong></p><p><strong>Results</strong>: 20 patients were treated using plate osteosynthesis, 18 of them had excellent KSS scores, 2 patients recorded good scores, average range of flexion was 126^o, no incidences of superficial or deep infections were seen in any of them. Bone consolidation was achieved around 12 weeks in plate fixation group of the16 patients treated using JESS, 12 had excellent scores, 4 recorded a good score, average range of flexion was 118^o, superficial infection was seen in 2 patients, with no incidence of deep infection. Bone consolidation was achieved around 16 weeks in JESS group.</p><p><strong>Conclusions</strong>: Both open reduction internal fixation (ORIF) with plating and JESS appear to be adequate fixation methods for complex proximal tibial fractures, but as per our study plate fixation resulted in earlier bone consolidation and gave a slightly better functional outcome compared to JESS.</p>

External flail chest stabilization; The simple, low-cost way

Flail chest is a life-threatening clinical entity which can be complicated by respiratory insufficiency. Paradoxical motion of a part of chest wall is the basic cause to put the blame on. Consequently, stabilization of the chest wall is occasionally of paramount importance to achieve early extubation in a patient with post-trauma respiratory insufficiency. Hereby, a simple, low cost, harmless and effective approach of external stabilization is presented.

Toward an Integrated Policy Framework

Policymakers often face difficult tradeoffs in pursuing domestic and external stabilization objectives. The paper reflects staff’s work to advance the understanding of the policy options and tradeoffs available to policymakers in a systematic and analytical way. The paper recognizes that the optimal path of the IPF tools depends on structural characteristics and fiscal policies. The operational implications of IPF findings require careful consideration. Developing safeguards to minimize the risk of inappropriate use of IPF policies will be essential. Staff remains guided by the Fund’s Institutional View (IV) on the Liberalization and Management of Capital Flows.