ResearchPad - 63 https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Dielectric-induced surface wave radiation loss]]> https://www.researchpad.co/article/Nf744108f-3177-456a-9f7b-980cfcadf3d0 We investigate a model which shows how the introduction of a perturbing dielectric close to an electromagnetic surface wave leads to radiation away from the surface through the dielectric. This resembles a surface waveguide passing through a wall or being deployed underground. Our theory, which is based on the mode-matching technique, allows quantitative determination of losses from a bound surface wave mode up to the point of its complete extinction. For a surface wave supported by a coated, conducting sheet the attenuation due to the perturbing dielectric is calculated for a number of frequencies, permittivities of the perturbation and separations between the sheet and the perturbing dielectric. The accuracy of our results is verified by simulation of the system with a full-wave numerical solution. Finally, we report experimental data of perturbed surface waves on a cable, which are in qualitative agreement with our model.

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<![CDATA[Multimodal nocturnal seizure detection in a residential care setting]]> https://www.researchpad.co/article/5c19b3c5d5eed0c484c54ac6

Objective

To develop and prospectively evaluate a method of epileptic seizure detection combining heart rate and movement.

Methods

In this multicenter, in-home, prospective, video-controlled cohort study, nocturnal seizures were detected by heart rate (photoplethysmography) or movement (3-D accelerometry) in persons with epilepsy and intellectual disability. Participants with >1 monthly major seizure wore a bracelet (Nightwatch) on the upper arm at night for 2 to 3 months. Major seizures were tonic-clonic, generalized tonic >30 seconds, hyperkinetic, or others, including clusters (>30 minutes) of short myoclonic/tonic seizures. The video of all events (alarms, nurse diaries) and 10% completely screened nights were reviewed to classify major (needing an alarm), minor (needing no alarm), or no seizure. Reliability was tested by interobserver agreement. We determined device performance, compared it to a bed sensor (Emfit), and evaluated the caregivers’ user experience.

Results

Twenty-eight of 34 admitted participants (1,826 nights, 809 major seizures) completed the study. Interobserver agreement (major/no major seizures) was 0.77 (95% confidence interval [CI] 0.65–0.89). Median sensitivity per participant amounted to 86% (95% CI 77%–93%); the false-negative alarm rate was 0.03 per night (95% CI 0.01–0.05); and the positive predictive value was 49% (95% CI 33%–64%). The multimodal sensor showed a better sensitivity than the bed sensor (n = 14, median difference 58%, 95% CI 39%–80%, p < 0.001). The caregivers' questionnaire (n = 33) indicated good sensor acceptance and usability according to 28 and 27 participants, respectively.

Conclusion

Combining heart rate and movement resulted in reliable detection of a broad range of nocturnal seizures.

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<![CDATA[Anconeus Muscle-Pedicle Bone Graft With Periosteal Coverage for Osteochondritis Dissecans of the Humeral Capitellum]]> https://www.researchpad.co/article/5b436150463d7e273780c149

Background:

Treatment of advanced osteochondritis dissecans (OCD) of the capitellum is controversial, especially in moderate-sized lesions.

Purpose:

To establish a treatment algorithm for capitellum OCD, we tried to determine the utility of and problems associated with anconeus muscle-pedicle bone graft with periosteal coverage (ABGP) for the treatment of moderate-sized articular OCD defects of the capitellum.

Study Design:

Case series; Level of evidence, 4.

Methods:

According to our protocol for elbow OCD, 16 patients (15 males, 1 female; age range, 12-17 years; mean age, 14.4 years) with a moderate-sized OCD lesion of the humeral capitellum were treated with ABGP. All patients had a full-thickness, unstable OCD lesion that was 10 to 15 mm in diameter. Clinical results and postoperative images, including radiographs and magnetic resonance imaging (MRI), were evaluated at a mean follow-up of 31 months (range, 24-66 months).

Results:

All but 1 patient had functional improvement after the procedure and returned to previous sporting activities within 6 months. One female patient needed 1 year for functional recovery due to development of postoperative chronic regional pain syndrome (CRPS). Two patients required additional surgery, including shaving of the protruding cartilage, and they returned to their previous level of activity. Mean arc of range of flexion-extension motion was 117° preoperatively and 129° at follow-up (P = .031). Mean elbow function as assessed with the clinical rating system of Timmerman and Andrews was 136 preoperatively and 186 at follow-up (P = .00012). Bony union of the graft as demonstrated by trabecular bone bridging on radiography was obtained within 3 months in all patients. Postoperative MRI was examined for 14 patients at 6 to 12 months after the procedure; the MRIs showed near-normal articular surface integrity in 9 of the 14 patients (64%) and underlying bony structure in 10 of the 14 patients (71%).

Conclusion:

Improvement after ABGP was obtained within 6 months in all except 1 patient, who developed CRPS. Postoperative radiography and MRI revealed near-normal articular surface integrity or underlying bony structure. This procedure is useful as a surgical option for a moderate-sized articular OCD lesion in the elbow.

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<![CDATA[Concussions From Youth Football]]> https://www.researchpad.co/article/5af3631d463d7e5f595b1795

Background:

Youth football programs across the United States represent an at-risk population of approximately 3.5 million athletes for sports-related concussions. The frequency of concussions in this population is not known.

Study Design:

Descriptive epidemiology study.

Methods:

Over an 11-year span from January 2002 to December 2012, the authors reviewed the concussions sustained by athletes aged 5 to 13 years while playing football, as evaluated in emergency departments (EDs) in the United States and captured by the National Electronic Injury Surveillance System (NEISS) database of the US Consumer Product Safety Commission.

Results:

There were 2028 (national estimate, 49,185) young football players evaluated in NEISS EDs with concussion from 2002 to 2012. There were 1987 (97.9%) males and 41 (2.1%) females, with a mean age of 11.2 years. The total number of concussions reported increased with age and by year. The majority of concussions were treated in the outpatient setting, with 1878 (91.7%) being treated and released. The total number of head-to-head injury mechanisms mirrored the total number of concussions by year, which increased throughout the 11-year span. The total number of players experiencing a loss of consciousness increased throughout the study period but did not match the total number of concussions over the 11-year time period. Fractures occurred in 11 (0.5%) patients, with 2 being severe (1 skull fracture and 1 thoracic compression fracture).

Conclusion:

Within the 5- to 13-year age range, there were a significant number of young athletes who presented to EDs with concussion as a result of playing organized football. Older children may be at greater risk for sustaining concussions, fractures, and catastrophic injuries while playing football when compared with younger children.

Clinical Relevance:

Younger children are more susceptible to long-term sequelae from head injuries, and thus, improved monitoring systems for these athletes are needed to assist in monitoring patterns of injury, identifying risk factors, and driving the development of evidence-based prevention programs.

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<![CDATA[The Risk of Transphyseal Drilling in Skeletally Immature Patients With Anterior Cruciate Ligament Injury]]> https://www.researchpad.co/article/5b02e38b463d7e60762c6798

Background:

Anterior cruciate ligament reconstruction (ACLR) in skeletally immature patients can result in growth plate injury, which can cause growth disturbances.

Purpose:

To evaluate radiological tibial and femoral length and axis growth disturbances as well as clinical outcomes in skeletally immature ACLR patients treated with a transphyseal drilling technique.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 39 pediatric patients with ACL injury and open physes at time of surgery, as diagnosed clinically and with magnetic resonance imaging (MRI), were treated using transphyseal ACLR using hamstring graft. Mean patient age was 11.7 years (range, 9.0-14.0 years). Patients were evaluated with full extremity radiographs measuring leg length discrepancy and malalignment, as well as clinical evaluation with KT-1000 arthrometer measurements and Tegner activity scale and Knee injury and Osteoarthritis Outcome Score (KOOS) outcomes after follow-up of 68 months (range, 29-148 months).

Results:

Of the 39 initial patients, 33 were evaluated both clinically and radiographically. We found a mean femoral length shortening of 3.5 mm (P = .01) on the operated leg. Eight patients (24%) had a more than 10-mm shortening of the operated leg, whereas only 1 patient (3%) had a 10-mm shortening of the nonoperated leg. In 27 of 33 patients (82%; P < .001), the anatomic femoral axes of the operated leg were found to be more than 2° of valgus compared with the nonoperated leg. The tibial anatomic axes changed into a less pronounced varus angulation (P = .02). The femoral-tibial anatomic axes were not significantly different when comparing the 2 legs. We did not find any statistical difference in growth arrest comparing patients treated surgically at the ages of 13 to 14 years to patients younger than 13 years. Tegner and KOOS scores were significantly lower among girls compared with boys. Side-to-side KT-1000 arthrometer difference improved from 5.2 mm preoperatively to 1.6 mm at follow-up.

Conclusion:

This study shows that transphyseal ACLR in children results in minor length growth disturbances in 24% of patients. The surgically induced distal femoral valgus angulation is counterbalanced by a proximal tibial varus angulation. Growth disturbance after surgery is not associated with a certain pediatric age group. Otherwise, transphyseal ACLR has satisfactory clinical outcomes, with good subjective outcomes, function level, and knee stability.

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