By C. Mazin. University of Maryland Baltimore County. 2018.

Bone Scanning and Single Photon Emission Computed Tomography Bone scans are widely used for differentiating acute from older (subacute or chronic) compression fractures endep 75mg cheap. Old fractures should be metabolically inactive buy 75 mg endep overnight delivery, while recent fractures should have high radiotracer uptake (53) cheap endep 10 mg otc. We did not identify articles that allowed us to calculate sensitivity and specificity for this condition cheap 10 mg endep fast delivery. What Is the Role of Imaging in Patients with Back Pain Suspected of Having Ankylosing Spondylitis? Summary of Evidence: There are only a few studies that attempt to deter- mine which imaging modality is best for diagnosing ankylosing spondyli- tis (AS) generic endep 10mg fast delivery. Plain radiographs and bone scans with SPECT both have relatively high specificity; specificity on CT and MR is currently not available. Plain radiographs appear to be adequate for initial imaging in a patient sus- pected of having AS. Plain Radiographs The characteristic imaging findings in AS are osteitis, syndesmophytes, erosions, and sacroiliac joint erosions, with joint erosions occurring rela- tively early and being readily detectable by radiography. While the sensi- tivity of radiographs is poor (45%), the specificity appears high (100%), although in the single study examining this issue, spectrum bias likely inflated both estimates (moderate evidence) (73). Computed Tomography We found no adequate data on the accuracy of CT for ankylosing spondylitis. Bone Scanning and Single Photon Emission Computed Tomography In two studies, bone scan sensitivity ranged from 25% to 85%, with the higher sensitivity achieved by using SPECT (73,74) (both studies moderate evidence). These studies suffered from a lack of high-quality reference standards and independent interpretations. What Is the Role of Imaging in Patients with Back Pain Suspected of Having Spinal Stenosis? On MR, the radiologists’ general impression, rather than a mil- limeter measurement, is valid. Plain Radiographs No studies provided good estimates of radiographic accuracy in detecting central stenosis. Since radiographs can only estimate bony canal compro- mise, the sensitivity for central stenosis is undoubtedly poorer than that of CT or MR, which depict soft tissue structures. Methodologic quality was variable but generally poor, making pooling of the data impractical. Central stenosis is also common in asymptomatic persons, with a prevalence of 4% to 28% (limited evidence) (76), and thus the specificity of CT for central stenosis, as it is for disk herniations, is likely less than the reported estimates. Of note, two recent studies suggest that the readers’ general impres- sion of central stenosis is valid. In a retrospective study comparing elec- tromyogram (EMG) findings to radiologists’ MR interpretations, Haig Chapter 16 Imaging of Adults with Low Back Pain in the Primary Care Setting 311 et al. Two neurosurgeons, two orthopedic spine surgeons, and three radiologists reviewed MRs from patients with a clinical and radiologic diagnosis of lumbar spinal stenosis. In concordance with Haig’s work, they found that the readers’ subjective evaluation of stenosis significantly correlated with the calculated cross-sectional area (p <. Bone Scanning and Single Photon Emission Computed Tomography Bone scanning has no role in central stenosis imaging. Summary of Evidence: The majority of patients with LBP think imaging is an important part of their care. However, in patients who are imaged, results of satisfaction with care are conflicting and overall not significantly higher than in those who were not imaged. Additionally, when plain radi- ographs are obtained, outcome is not significantly altered (and in some cases, is worse). But when MR or CT is used early in the workup of LBP, there is a very slight improvement in patient outcome. Supporting Evidence: While the majority of studies attempt to validate a modality by its diagnostic accuracy, possibly more important is whether the test actually alters patient outcomes. At 6 weeks and at 1 year, there was no difference between the groups in physical functioning, disability, pain, social functioning, general health, or need for further referrals.

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Provide an estimate of the mass moment of inertia of your forearm about the three principal axes that pass through its center of mass purchase endep 10 mg. The moment of inertia of an athlete with respect to his cen- ter of mass along an axis from posterior to anterior was experimentally determined to be equal to Ic 5 13 endep 50 mg with mastercard. Represent the athlete as a slender rigid rod and determine an approximate value (I*) for his moment of inertia buy generic endep 75mg on-line. What would be the effective length h* of the rod that would correctly predict the moment of inertia of the athlete? The parameter H is the height of the adolescent order endep 10mg without prescription, measured in meters discount endep 25mg with amex, and W is his mass, measured in kilograms. To check whether this formula could also be applicable to adult men, a group of Air Force researchers measured the mass moment inertia of a select group of Air Force men. Following are the data obtained for three men in the group: Age Height (m) Mass (kg) I33 (kg-m2) I11 (kg-m2) 29 1. How far off would be the predictions of these mass moment of inertia compo- nents if one represented each individual with a slender rod whose length and mass are equal to that of the individual? Determine if there are phenome- nological equations already developed for these subpopulations. If not, how would you go about coming up with your own set of empirical equations? Provide an estimate of the spatial location of the center of mass C of the dancer leaping in air as shown in Fig. Specify in detail any addi- tional assumptions you had to make to arrive at your results. Note that you need to establish a reference frame to compute and specify the lo- cation of the center of mass. In this exercise, the man is represented as a rod with uniform distribution of mass (b). Determine the vertical ground forces acting on a man at the feet (FF e2) and hands (FH e2) while performing push-ups as shown in Fig. At the in- stant considered (t 5 0), the angle his body makes with the horizontal plane (u) is 20°. The body is aligned straight and rotates around the fixed point O as shown in the figure. The fact that FF is negative implies that somebody must have been pressing at the ankles of the man do- ing the push-ups. They are hinged together and in the resting position are aligned on a straight line. The rod B1 slides on the smooth, frictionless surface of the floor and the center of mass of the system moves parallel to the floor. Determine the reaction force F2 and the angular accelerations of B1 and B2 right after the release. Note that this two-rod system might capture some of the essential features of sideway falls. Among the elderly population, a sideway fall is a most frequent cause of hip fracture. The answer to this problem may pro- vide information about the nature of shape change during such a fall 116 4. Sideway fall of a person onto a floor (left) and its representation us- ing a two-link model (right). A diver is airborne in full extended position rotating with clockwise angular velocity v 525 rad/s. At time t 5 0 he begins to pull his legs toward his chest at a rate of 2p rad/s (Fig. Deter- mine the angular velocity of his trunk and that of the lower extremi- ties. Assume that the diver is composed of two slender rods each weigh- ing 32 kg and 0. A building is in static equilib- rium because its weight is balanced vertically by the upward ground force exerted on it. A ballerina keeps a delicate balance by positioning her cen- ter of mass on a vertical line that passes through the tip of her feet in con- tact with the floor.

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In one review of 1153 knee radiographs requested by primary care physi- cians 75mg endep with amex, most imaging reports (59%) described normal anatomy or degen- erative changes (29%) (62) effective 50 mg endep. In 20% of patients radiography was used to bolster the case for trusted 75mg endep, or against discount 75mg endep otc, referral to a specialist order 50mg endep overnight delivery. Other important changes in therapy based on radiography findings were observed in only 3% of cases (62). Still, many primary care physicians feel that radiographs are neces- sary in order to reassure patients, to justify a specialist referral, or for other nondiagnostic reasons (59,61). Therefore, continued use of radiography for patients with chronic knee pain seems inevitable. However, trial data have demonstrated that radiography requests can be reduced by regular edu- cational messages reminding physicians of the limited value of radiogra- phy in this setting (64,65). Special Case: Imaging of the Painful Prosthesis The potentially infected knee prosthesis is a case where the evidence for the various imaging investigations is rather weak. The patient presents with pain and perhaps instability some months/years after a successful knee replacement. Plain radiography of the total extent of the prosthesis (including the femoral and tibial tips) is performed; interpretation is easier if these images can be compared with those obtained at the postopera- tive stage, if available; lucency around the stem of the prosthesis may be associated with loosening or infection. Despite software developments to reduce artifacts from the metallic prosthesis, neither CT nor MRI can offer much here. Skeletal scintigraphy can provide evidence of abnormal osteoblastic activity around the prosthesis, which should be more intense in relation to infection than loosening; some centers proceed to white cell scintigraphy, which may help in this distinction. Other centers use arthrog- raphy, which may provide a microbiologic sample if there is a large effu- sion. In any event, there is a wide range of sensitivities and specificities in these tests. Interpretation is also complex because the investigations are often spread out over several weeks. Furthermore there is frequently no gold standard, as the ultimate arbiter, the decision to perform revision surgery, is not undertaken lightly and is ultimately still based on clinical rather than radiologic grounds. At present, there is insufficient evidence (level IV) to recommend any particular imaging approach. Summary of Evidence: Conventional teaching advocates both pre- and postreduction radiographs for patients with clinically suspected shoulder dislocation, and survey data confirm that many hospitals follow this rec- ommendation (66). However, more recent research has provided limited evidence (level III) that radiographs are not necessary in most patients with recurrent atraumatic dislocation. Furthermore, there is limited evidence (level III) that the prereduction radiograph may be omitted in traumatic joint dislocations provided that the clinician is confident of the diagnosis. An alternative approach that eliminates the postreduction radiograph in patients with prereduction radiographs demonstrating dislocation and no fracture is also supported by limited evidence (level III). Limited evidence also suggests that, in patients without obvious shoulder deformity, radi- ography should be targeted at those with bruising or joint swelling, or with a history of fall, pain at rest, or abnormal range of motion. However, more research is needed to validate these guidelines and to provide head-to- head comparisons of selective imaging strategies to demonstrate the rela- tive feasibility and cost-effectiveness of implementation. The questions posed differ according to the nature of the injury and the age of the patient. In the elderly, a fracture of the surgical neck of humerus is common after a fall. In the younger patient the clinician may be more worried about possible dislocation, especially in those with recur- rent episodes where the chance of recurrent dislocation is high. It is in this precise group of young patients that ionizing radiation should be kept as low as reasonably achievable and requests for imaging kept to a minimum. A retrospective study conducted in a North American medical center found that radiographs were performed in 59% of emergency department patients with shoulder pain (67). Twenty percent of these radiographs provided therapeutically important information (defined as glenohumeral dislocation, fracture, severe acromioclavicular joint separation, infection, or malignancy). Hendey (68) has demonstrated that, for patients with suspected recur- rent relatively atraumatic dislocation, physicians were certain of the dislo- cation in more than 90% of cases. In every case this preimaging confidence was justified by radiographic evidence of dislocation without fracture. After reduction of these atraumatic dislocations, physicians were also con- fident that relocation had been achieved in more than 90% of patients; again this was subsequently radiographically confirmed in all cases. Although this work requires validation, it does provide limited evidence (level III) that radiographs are not routinely indicated in this well-defined recurrent dislocation population. Some have suggested that many postreduction radiographs are not diagnosti- cally or therapeutically useful when the prereduction radiograph demon- strates dislocation without fracture (68–70).

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Company Name: Motion Lab Systems best 50 mg endep, Incorporated Address: 4326 Pine Park Drive Baton Rouge cheap endep 75mg online, LA 70809-2397 USA Telephone: + 1 225 928 4248 Facsimile: + 1 225 928 0261 e-mail: sales@emgsrus buy 50 mg endep. The frequency response of the system is 20 to 2000 Hz and includes adjustable low-pass filters endep 25 mg amex. The subject carries the control unit trusted endep 50 mg, either on a belt or a jacket, and the signals are multiplexed and transmitted to the base computer via a thin and flexible coaxial cable. This cable also carries an isolated DC supply which means that the control unit does not need batter- ies. The 16 channel EMG system has an additional 4 channels to transmit other signals (such as goniometers, electrocardiograph, respiration, en- ergy consumption, etc. The foot switches, which are de- signed to measure standard temporal-distance parameters, are thin (0. In addition, there are specially designed cords and cables to connect the foot switches to the con- trol unit. Besides its EMG analysis software, Motion Lab Systems also supply a number of software packages that are especially use- ful for the gait analyst. The program RData2 translates C3D files into ASCII text, including the DST format used in GaitLab. The program MLSviewer enables the user to view any DST file, including the Frame = 24 Time = 0. The C3D file editor program offers filtering, interpolation, and pa- rameter editing, including the creation of C3D files from an Excel spreadsheet. Company Name: MusculoGraphics, Incorporated Address: 1840 Oak Avenue Evanston, IL 60201 USA Telephone: + 1 847 866 1882 Facsimile: + 1 847 866 1808 e-mail: info@musculographics. SIMM is a graphics-based package that enables the user to develop and analyse musculoskeletal models very rap- idly. The model consists of 3D solid representations of bones, muscles, ligaments and other structures. SIMM calculates the joint moments that each muscle can generate at any body position. By manipulating the model using the graphical interface, the user can quickly explore the effects of changing musculoskeletal geometry, and other model parameters, on the muscle forces and joint mo- ments. Whereas SIMM was originally designed to run on Silicon Graphics workstations, it has recently been ported to the Windows 95/98/NT platform. It is designed to read in files written by movement analysis systems, such as the C3D files cre- ated by the Vicon system from Oxford Metrics. The software cre- ates a 3D animation showing body motion, muscle activity and ground reaction forces, emphasising the integration of these param- eters (cf. Company Name: Northern Digital, Incorporated Address: 103 Randall Drive Waterloo Ontario N2V 1C5 Canada Telephone: + 1 519 884 5142 Facsimile: + 1 519 884 5184 e-mail: sales@ndigital. The targets consist of active infrared light emitting diodes which are pulsed sequentially so that as the number of targets increases the sampling rate decreases. The 3D data are available in real time and unique target identification is achieved, even when a target disap- pears from view temporarily. Because the Optotrak instrument is calibrated in the factory by NDI, there is no need for calibration in the field prior to data capture. The Optotrak has a field of view of 34º and can track up to 256 targets, thus allowing very detailed motions to be captured. Its disadvantages include subject encum- brance by the trailing cables that strobe the targets and provide power (although an optional tetherless controller minimises this prob- lem), and only one side of the body can be studied with a single instrument. For tracking bilateral movements such as human gait, it is necessary to acquire a second Optotrak device, increasing the cost significantly. NDT has recently introduced a cost-effective sys- tem called Polaris which is based on two rectangular CCDs and it can track the 3D positions of either active or passive targets in real time. Company Name: Novel GmbH Address: Ismaningerstrasse 51 Munich 81675 Germany Telephone: + 49 89 417 7670 Facsimile: + 49 89 417 76799 e-mail: novel@novel. The insole has 85 separate transducer sites (each about 18 mm x 18 mm) while the pressure mat has an area of 0. The sampling rate is up to 100 frames/s for the two systems; the pressures are colour-coded in seven different colour values, similar to thermographic analysis, and have a numerical value between 0. Unfortu- nately, colour cannot be printed in journal articles because of the prohibitive cost, but this technique clearly enhances understanding and pinpoints areas of unduly high or low pressure. The advantages of these systems are the intuitive method of displaying pressure data, good spatial resolution and pressure range, simplicity of operation Frame = 25 Time = 0. The disadvantages are the relatively small size of the platform, which could lead to targeting, encumbrance of the sub- ject by the trailing wires of the pressure insole system, and the lack of shear force information (i.

10 of 10 - Review by C. Mazin
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Total customer reviews: 45



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