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Biomedical subjects

M Scheidler

Publications and source records attributed to M Scheidler.

10 recordsLinked to original sources
PubMed2000

Effectiveness of wound care products in the transmission of acoustic energy.

BACKGROUND AND PURPOSE: Ultrasound is often recommended in the treatment of people with partial and full-thickness wounds. Many treatments are performed over a hydrogel sheet or semipermeable film dressing. The purpose of this in vitro study was to examine the effectiveness of 4 hydrogels (Nu-Gel, ClearSite, Aquasorb Border, and CarraDres) and 4 film dressings (CarraSmart Film, J&J Bioclusive, Tegaderm, and Opsite Flexigrid) in ultrasound transmission. METHODS: The amount of sound energy transmitted through each product and interposed pig tissue was measured using an oscilloscope to display the intensity of sound energy delivered by the transducer. Five intensities at a frequency of 3.3 MHz were studied. RESULTS: Results were expressed as the mean ((SD) percentage of voltage transmitted compared with a gel baseline. Nu-Gel was the most efficient hydrogel (77.2%(4.6%), followed by ClearSite (72.0%(2.2%), Aquasorb Border (45.3%(2.1%), and CarraDres (42.8%(5.9%). The 4 film dressings, in order of efficiency, were CarraSmart Film (60.5%(4.4%), J&J Bioclusive (53.2%(2.4%), Tegaderm (47.1%(2.3%), and Opsite Flexigrid (31.5%(4.0%). CONCLUSION AND DISCUSSION: Transmissivity of wound care products used to deliver acoustic energy during ultrasound treatment of wounds varies greatly among dressing products. We believe that clinicians can use our findings as a part of the clinical reasoning process that they use to select an optimal wound dressing.

Animals↗
PubMed1997

Heterotopic ossification after total knee arthroplasty. 54/615 cases after 1-6 years' follow-up.

We found heterotopic ossifications in 54 (9%) of 615 cases after total knee arthroplasty. The largest ossifications were located in the anterior distal femur. In 12 cases smaller ossifications were found in other knee regions. The development of heterotopic ossification showed a positive correlation with hypertrophic arthrosis and a negative correlation with rheumatoid arthritis. We propose a new 3-grade classification which refers only to the anterior distal femoral region. Grade III heterotopic ossifications occurred in 4 patients (4 knees) who had clinical symptoms; 2 were successfully reoperated with removal of the ossifications. Prophylaxis should be considered in patients with marked hypertrophic arthrosis or marked periosteal damage to the anterior distal femur.

Aged↗
PubMed1997

The need for a dual rating system in total knee arthroplasty.

The sequential course of the knee score and functional score of the Knee Society rating system of 276 press fit condylar modular unconstrained total knee arthroplasties performed for osteoarthritis between June 1988 and December 1992 was documented prospectively. The knee score increased significantly and stayed on a constant level from 2 years on, whereas the function score reached a maximum at 2 years and declined subsequently. Multiple regression analysis was performed testing the statistical significance and correlation of preoperative predictors with criteria at followup to determine their influence on outcome. Preoperative predictors were knee score and function score, body mass index, age, gender, patient category, and implant factors. Criteria studied were pain, knee score, and function score at 2 years followup. The function score is influenced significantly by the walking distance, age, body mass index, and patient category correlating moderately. The knee score is not affected by any of these factors. Pain was found to correlate low with the walking distance. Rating systems are influenced by numerous factors linked to the patient's general health and condition. Their impact on the overall result can be controlled by separate rating of the knee score and function score as the dual Knee Society rating system does. Scoring systems adding up knee and functional rating to an overall result should not be used. There is a need for additional improvement of total knee arthroplasty rating such as patient based evaluation and establishing reliability and validity.

Activities of Daily Living↗
PubMed1996

Amblyopic quasi-blindness for image structure.

Human amblyopes display reduced contrast sensitivities, suffer from perceptual distortion, and their letter acuities are worse than is predicted from grating visibility. We sought the origin of these dysfunctions by measuring normal and amblyopic sensitivities to various forms of well-defined image distortion, namely band-limited phase quantization, phase quantization with additional amplitude modulation, and grey-scale modification. Our results prove the existence of an amblyopic quasi-blindness to image structure, that cannot be explained in terms of contrast detection. We discuss these findings within the computational scheme of image decomposition into local amplitude and local phase values. they are consistent with the assumption of amblyopic eyes beings impaired in processing local phase but having the local amplitude (or "energy", possibly at reduced gain) at their disposal. Phrased in physiological terms, we propose a scheme of complex-cells-only vision in amblyopia. We also provide a demonstration of how amblyopic eyes may see the test stimuli and natural images by generating local amplitude and phase representations at limited phase resolution.

Amblyopia↗
PubMedDate not supplied

[Follow-up studies after bicondylar superficial replacement of rheumatoid knee joint destruction].

This study documents prospectively the Knee Society knee- and function score of 28 patients with rheumatoid arthritis with 34 PFC unconstrained total knee arthroplasties from preoperative values on at yearly intervals. The average follow-up period was 3.4 years (range 2-5.5 y). At last follow-up over 80% of the knees were painfree. All but one patient could walk more than 500 m. Knee and function score increased significantly from 30.1 resp. 35.0 to 83.8 resp. 74.6 (P < 0.000001). Postoperatively the knee score rose soon to a constant level whereas the function score showed a continuous slow increase up to 5 years. We observed one deep venous thrombosis and one subluxation. At an intermediate follow-up rheumatoid knees are clinically and functionally successfully operated on using an unconstrained TKA. Pain relief is excellent. We recommend the use of a scoring system assessing knee and functional results separately.

Adult↗
PubMedDate not supplied

[Comparison of knee and functional outcomes of patients lost to follow-up with patients remaining in a prospective total knee arthroplasty study].

PURPOSE: Survival analysis is correct when patients lost to follow-up are as healthy as patients still being followed. Therefore, the results of patients who missed the follow-up visits were determined and compared with the results of the patients still in the study. Revision surgery and the reasons for failing to reattend the follow-up visits were recorded. METHODS: Of 680 unconstrained total knee arthroplasties implanted between 1989 and 1994 with yearly patient evaluation according to the Knee Society 53 patients with 60 implants died, 17 patients with 19 implants could not be used for the study and 21 patients with 24 implants were interviewed by telephone. 56 patients with 61 implants lost to follow-up were examined by visiting them at their homes (drop-outs) and compared to the 460 patients with 516 implants still in the study. RESULTS: The drop-outs were older at surgery and had more medical infirmity than the remaining patients. Drop-outs had a lower mean function score and a tendency to a lower mean knee score at follow-up compared with the patients in the study. No revision surgery was performed in drop-out knees. Reasons for not reattending the follow-up were mainly long travel and health. CONCLUSIONS: Patients reattending a study are healthier than drop-outs. This censoring mechanism limits correct survival analysis. A complete follow-up of patients and separate assessment of knee and functional status with reliable and valid instruments is required.

Aged↗
PubMedDate not supplied

[Is use of the Knee Society Roentgenographic Evaluation and Scoring System for radiologic control of knee prostheses reliable?].

PURPOSE: To follow the radiographic parameters of prosthetic loosening of the Knee Society Roentgenographic Evaluation and Scoring System (KSRESS) and to test their clinical relevance. METHODS: This prospective study documents the use of the KSRESS and clinical rating system in 333 primary posterior cruciate retaining PFC total knee arthroplasties preoperatively, at 3 month and at yearly intervals postoperatively. The average follow-up period was 3.2 years (range 2-5.5 y). RESULTS: The average component position and alignment angles remained unchanged at biomechanically correct angles during the follow-up period. Radiolucent lines were observed regularly at the edges of the tibial and femoral components. The average total radiolucent lines score decreased for the tibial component. Patellar and femoral lucencies remained unchanged. The total radiolucent lines scores did not correlate with postoperative pain, body-mass-index, alignment, stability, knee and function score. Four revisions, one with relevant radiolucent lines, had to be performed. CONCLUSIONS: The KSRESS is a useful tool. Standardisation of roentgenograms is mandatory. The PFC arthroplasty, the operative technique and the instruments ensure a biomechanically correct implantation.

Adult↗