scholarly journals Exo-Leg: An Active Single-Leg External Walking Assist Device

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Thomas Coughlin ◽  
Jessica L. Knight ◽  
Alex Hinkle ◽  
Matt Van Cleve ◽  
Salam Al-Omaishi ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Pressure Sensors ◽  
Trigger Points ◽  
Simulation Software ◽  
Foot Drop ◽  
Knee Joints ◽  
Assist Device ◽  
Lower Extremity Weakness ◽  
Control Interface ◽  
The Individual

Lower extremity weakness is a serious problem afflicting people all over the world. Until recently, the mobility options for people with this condition have been confining and limit the individual’s functionality. Walking assist devices are presently in development to restore hands-free walking to people with lower extremity weakness. These devices provide the necessary support and power to enable the individual to restore normal ambulation. The proposed design of exoleg, a single leg external walking assist device, addresses the demographic of people with lower extremity weakness. The design includes replication of the gait cycle utilizing mechanical links and user control interface with emphasis on safety. The design couples the actuation of the knee and hip through the use of linkages connected to a single motor. The actuation of the hip is controlled by a 4 bars crank-rocker linkage system while the knee is actuated by corresponding linkages (designed in WORKING MODEL 2D, a commercial simulation software) that generates the knee kinematic profile. The angular profiles of the knee and hip actuations are compared with the actual knee and hip angular trajectories. The frame of the device incorporates a passive ankle stabilization system to compensate for the effects of foot drop. The system utilizes feedback from trigger points from pressure sensors on the foot and goniometers at the hip and knee joints to measure the angulations in gait to keep the device in synchronization with natural ambulation. An on-board microprocessor receives the feedback from the trigger points and sends the actuation signal to the motor. A conceptual design of electrostatic actuator motor is also proposed to keep the device light weight and compact.

Two-level thoracic pedicle subtraction osteotomy for progressive post-laminectomy kyphotic deformity following resection of an unusual thoracolumbar intradural extramedullary tumor

2012 ◽  
Vol 10 (4) ◽  
pp. 334-339 ◽  
Author(s):  
Brian J. Kelley ◽  
Michele H. Johnson ◽  
Alexander O. Vortmeyer ◽  
Brian G. Smith ◽  
Khalid M. Abbed
Keyword(s):  
Lower Extremity ◽  
Poor Prognosis ◽  
Pedicle Subtraction Osteotomy ◽  
Foot Drop ◽  
Kyphotic Deformity ◽  
Neurological Deficits ◽  
Lower Extremity Function ◽  
Lower Extremity Weakness ◽  
Postoperative Course ◽  
Extramedullary Tumor

The authors report a case in which multilevel thoracic pedicle subtraction osteotomy (PSO) was performed to correct post-laminectomy kyphotic deformity in a 9-year-old boy presenting with worsening lower-extremity neurological deficits. Five years prior to presentation, the patient underwent multilevel thoracolumbar laminectomies for resection of an atypical teratoid/rhabdoid tumor (AT/RT), a rare lesion that typically occurs intracranially and has a poor prognosis, making this particular presentation unusual and the patient's subsequent postoperative course remarkable. No fusion was undertaken at the time of resection, given the patient's age and presumptive poor prognosis. Over the next 5 years, the patient developed progressive thoracolumbar kyphotic deformity, with a Cobb angle greater than 110°, despite bracing, and bilateral lower-extremity weakness requiring ankle-foot orthotics for continued ambulation due to progressive foot drop. Worsening gait and the onset of respiratory issues prompted surgical intervention. Multilevel thoracic PSO and thoracolumbar fusion were performed, resulting in improved lower-extremity function and correction of the kyphotic deformity to approximately 65°. This report outlines an unusual AT/RT presentation and postoperative course and also discusses literature related to PSO within the context of pediatric kyphotic deformity. The authors' experience supports the use of multilevel PSO with fusion as a potential treatment option for significant pediatric thoracolumbar kyphotic deformity requiring surgical correction.

Combining Values

2002 ◽  
Vol 7 (2) ◽  
pp. 1-4, 12 ◽  
Author(s):  
Christopher R. Brigham
Keyword(s):  
Lower Extremity ◽  
Upper Extremity ◽  
Evaluation Method ◽  
Proximal Phalanx ◽  
Common Error ◽  
The Third ◽  
Whole Person ◽  
Impairment Ratings ◽  
Upper Extremity Impairment ◽  
The Individual

Abstract To account for the effects of multiple impairments, evaluating physicians must provide a summary value that combines multiple impairments so the whole person impairment is equal to or less than the sum of all the individual impairment values. A common error is to add values that should be combined and typically results in an inflated rating. The Combined Values Chart in the AMA Guides to the Evaluation of Permanent Impairment, Fifth Edition, includes instructions that guide physicians about combining impairment ratings. For example, impairment values within a region generally are combined and converted to a whole person permanent impairment before combination with the results from other regions (exceptions include certain impairments of the spine and extremities). When they combine three or more values, physicians should select and combine the two lowest values; this value is combined with the third value to yield the total value. Upper extremity impairment ratings are combined based on the principle that a second and each succeeding impairment applies not to the whole unit (eg, whole finger) but only to the part that remains (eg, proximal phalanx). Physicians who combine lower extremity impairments usually use only one evaluation method, but, if more than one method is used, the physician should use the Combined Values Chart.

Quick Reference: Chapter 3: The Musculoskeletal System and Chapter 4: The Nervous System

2000 ◽  
Vol 5 (3) ◽  
pp. 4-4
Keyword(s):  
Nervous System ◽  
Lower Extremity ◽  
Musculoskeletal System ◽  
Multistep Method ◽  
Manual Muscle Testing ◽  
Motor Deficits ◽  
Lower Extremity Weakness ◽  
Residual Symptoms ◽  
Muscle Testing ◽  
Almost All

Abstract Lesions of the peripheral nervous system (PNS), whether due to injury or illness, commonly result in residual symptoms and signs and, hence, permanent impairment. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, divides PNS deficits into sensory and motor and includes pain in the former. This article, which regards rating sensory and motor deficits of the lower extremities, is continued from the March/April 2000 issue of The Guides Newsletter. Procedures for rating extremity neural deficits are described in Chapter 3, The Musculoskeletal System, section 3.1k for the upper extremity and sections 3.2k and 3.2l for the lower limb. Sensory deficits and dysesthesia are both disorders of sensation, but the former can be interpreted to mean diminished or absent sensation (hypesthesia or anesthesia) Dysesthesia implies abnormal sensation in the absence of a stimulus or unpleasant sensation elicited by normal touch. Sections 3.2k and 3.2d indicate that almost all partial motor loss in the lower extremity can be rated using Table 39. In addition, Section 4.4b and Table 21 indicate the multistep method used for spinal and some additional nerves and be used alternatively to rate lower extremity weakness in general. Partial motor loss in the lower extremity is rated by manual muscle testing, which is described in the AMA Guides in Section 3.2d.

scholarly journals Temperature Profile in Rubber Injection Molding: Application of a Recently Developed Testing Method to Improve the Process Simulation and Calculation of Curing Kinetics

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 380
Author(s):  
Martin Traintinger ◽  
Roman Christopher Kerschbaumer ◽  
Bernhard Lechner ◽  
Walter Friesenbichler ◽  
Thomas Lucyshyn
Keyword(s):  
Injection Molding ◽  
Temperature Profile ◽  
Pressure Sensors ◽  
Simulation Software ◽  
Relative Degree ◽  
Actual State ◽  
Process Conditions ◽  
Inlet Temperature ◽  
Degree Of Cure ◽  
Mass Temperature

Injection molding of rubber compounds is an easily conducted yet sophisticated method for rubber processing. Simulation software is used to examine the optimal process conditions, identify failure scenarios, and save resources. Due to the complexity of the entire process, various aspects have to be considered in the numerical approach. This contribution focused on a comparison of process simulations with various definitions of the material’s inlet temperature, ranging from a stepwise increase, but constant temperature, to an exact axial mass temperature profile prior to injection. The latter was obtained with a specially designed, unique test stand consisting of a plasticizing cylinder equipped with pressure sensors, a throttle valve for pressure adjustments, and a measurement bar with thermocouples for the determination of the actual state of the mass temperature. For the verification of the theoretical calculations, practical experiments were conducted on a rubber injection molding machine equipped with the mold used in the simulation. The moldings, obtained at different vulcanization time, were characterized mechanically and the results were normalized to a relative degree of cure in order to enable comparison of the real process and the simulation. Considering the actual state of the mass temperature, the simulation showed an excellent correlation of the measured and calculated mass temperatures in the cold runner. Additionally, the relative degree of cure was closer to reality when the mass temperature profile after dosing was applied in the simulation.

scholarly journals Clinical and angioarchitectural characteristics of spinal vascular malformations of the cervical spine

2020 ◽  
Vol 32 (5) ◽  
pp. 755-762 ◽  
Author(s):  
Waleed Brinjikji ◽  
Elisa Colombo ◽  
Giuseppe Lanzino
Keyword(s):  
Cervical Spine ◽  
Lower Extremity ◽  
Clinical Presentation ◽  
Vascular Malformations ◽  
Case Series ◽  
Acute Onset ◽  
Lower Extremity Weakness ◽  
Arteriovenous Fistulas ◽  
Spinal Vascular Malformations ◽  
Interventional Neuroradiologist

OBJECTIVEVascular malformations of the cervical spine are exceedingly rare. To date there have been no large case series describing the clinical presentation and angioarchitectural characteristics of cervical spine vascular malformations. The authors report their institutional case series on cervical spine vascular malformations diagnosed and treated at their institution.METHODSThe authors retrospectively reviewed all patients with spinal vascular malformations from their institution from January 2001 to December 2018. Patients with vascular malformations of the cervical spine were included. Lesions were characterized by their angioarchitectural characteristics by an interventional neuroradiologist and endovascular neurosurgeon. Data were collected on clinical presentation, imaging findings, treatment outcomes, and long-term follow-up. Descriptive statistics are reported.RESULTSOf a total of 213 patients with spinal vascular malformations, 27 (12.7%) had vascular malformations in the cervical spine. The mean patient age was 46.1 ± 21.9 years and 16 (59.3%) were male. The most common presentations were lower-extremity weakness (13 patients, 48.1%), tetraparesis (8 patients, 29.6%), and lower-extremity sensory dysfunction (7 patients, 25.9%). Nine patients (33.3%) presented with hemorrhage. Fifteen patients (55.6%) had modified Rankin Scale scores of 0–2 at the time of diagnosis. Regarding angioarchitectural characteristics, 8 patients (29.6%) had intramedullary arteriovenous malformations (AVMs), 5 (18.5%) had epidural arteriovenous fistulas (AVFs), 4 (14.8%) had paraspinal fistulas, 4 (14.8%) had mixed epidural/intradural fistulas, 3 (11.1%) had perimedullary AVMs, 2 (7.4%) had dural fistulas, and 1 patient (3.7%) had a perimedullary AVF.CONCLUSIONSThis retrospective study of 27 patients with cervical spine vascular malformations is the largest series to date on these lesions. The authors found substantial angioarchitectural heterogeneity with the most common types being intramedullary AVMs followed by epidural AVFs, paraspinal fistulas, and mixed intradural/extradural fistulas. Angioarchitecture dictated the clinical presentation as intradural shunts were more likely to present with hemorrhage and acute onset myelopathy, while dural and extradural shunts presented as either incidental lesions or gradually progressive congestive myelopathy.

scholarly journals Sleep Apnea and Unilateral Upper and Lower Extremity Allodynia as a Result of a Large Thoracic Disc Herniation: A Case Report

2021 ◽  
Author(s):  
Tyler D. Alexander ◽  
Anthony Stefanelli ◽  
Sara Thalheimer ◽  
Joshua E. Heller
Keyword(s):  
Spinal Cord ◽  
Sleep Apnea ◽  
Sexual Dysfunction ◽  
Lower Extremity ◽  
Disc Herniation ◽  
Cord Compression ◽  
Thoracic Disc Herniation ◽  
Lower Extremity Weakness ◽  
Disc Herniations ◽  
Thoracic Disc

Abstract BackgroundClinically significant disc herniations in the thoracic spine are rare accounting for approximately 1% of all disc herniations. In patients with significant spinal cord compression, presenting symptoms typically include ambulatory dysfunction, lower extremity weakness, lower extremity sensory changes, as well as bowl, bladder, or sexual dysfunction. Thoracic disc herniations can also present with thoracic radiculopathy including midback pain and radiating pain wrapping around the chest or abdomen. The association between thoracic disc herniation with cord compression and sleep apnea is not well described.Case PresentationThe following is a case of a young male patient with high grade spinal cord compression at T7-8, as a result of a large thoracic disc herniation. The patient presented with complaints of upper and lower extremity unilateral allodynia and sleep apnea. Diagnosis was only made once the patient manifested more common symptoms of thoracic stenosis including left lower extremity weakness and sexual dysfunction. Following decompression and fusion the patient’s allodynia and sleep apnea quickly resolved.ConclusionsThoracic disc herniations can present atypically with sleep apnea – a symptom which may resolve with surgical treatment.

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