Basic theory, design, and preliminary evaluation of a laser scanner for shape sensing below-the-knee amputees

A scanner which produces surface profiles of residual limbs from below-the-knee amputees was constructed and evaluated. The scanner uses a turntable mounted laser to define a surface profile line, a charge-coupled-device video camera to view the profile, and a custom designed video processing board to extract profile data. A microcomputer is used to control data acquisition and provides the rapid processing capability necessary to resolve scan profile data into a three-dimensional numerical description of the surface in a timely and cost effective manner. Flexibility of use as well as positional accuracy and reproducibility indicate that the laser scanner is well suited to the task of surface scanning of residual limbs for below-the-knee amputees. Additionally, the laser profile scanning technique can be applied to other regions of the body where a mathematical description of the surface is useful, such as in radiotherapy treatment planning.

[Exercise test before prosthesis fitting in amputees with vascular insufficiency]

93 subjects (age = 65 +/- 10 years) with lower limb amputation ensuing from peripheral vascular disease performed a graded exercise test on arm cranking ergometer with an electromagnetic braking to assess their physical fitness and cardiac condition before starting a prosthetic training programme. The protocol was continuous with a workload increment of 10 watts every two minutes. Heart rate, blood pressure and ECG were recorded at each stage. Reasons to stop the test were 1) arm muscle fatigue, 2) reaching of target heart rate, 3) cardiovascular abnormalities. At the end of the test, the mean percentage of maximum heart rate was 53%, 92%, and 66% for each of these reasons, respectively (p less than .0001). Results showed that subjects who received a prosthesis had a higher exercise capacity than those who did not get a prosthesis (39.0 watts vs 18.5 watts, p less than 0.001). Furthermore, maximal oxygen uptake (4.4 METs vs 3.0 METs, p less than 0.001) and reached maximal heart rate (131 vs 110 bpm, p less than .005) were both higher in subjects of prosthesis group. Results suggest that a graded exercise test at the beginning of prosthetic training allows a rehabilitation team 1) to predict the success of the prosthetic process and 2) to identify subjects for which this process could increase the risks of health problems.

Prostheses and the forward reach of sitting lower-limb amputees

The hypothesis that prostheses improve the forward reach of sitting lower-limb amputees was tested. While sitting with only ischial support, ten unilateral below-knee (BK) amputees could reach farther when they wore their prostheses than when they did not, when reaching at 45 degrees toward or away from the side of the amputation, with mean differences (+/- 1 SD) of 10.7cm (+/- 6.9, p less than 0.0001) and 4.4cm (+/- 4.1, p less than 0.01), respectively. With ten unilateral above-knee (AK) amputees, the differences were not statistically significant. Seven bilateral amputees (mixed levels) were able to reach farther with their prostheses on than off, with mean differences of 41.2cm (+/- 9.5) and 31.5cm (+/- 7.9) for reaches at 0 degrees and 45 degrees, respectively (p less than 0.0001). With the prostheses off, their reach was significantly greater when their thighs were supported than when they were sitting with only ischial support. These findings suggest that (1) prostheses improve the anterolateral reach of unilateral BK amputees, and the straight forward and anterolateral reach of bilateral amputees; (2) when prostheses are not being worn, a sitting surface which provides support through the residual limbs improves forward reach; and (3) the design of AK prostheses should reflect the patient's needs, both standing and sitting.

Dysvascular amputee rehabilitation. The role of continuous noninvasive cardiovascular monitoring during physical therapy

Recognition of cardiac problems and their impact on the treatment of dysvascular amputees is important during rehabilitation because the energy demands and cardiac work loads of functional activities are substantially greater when performed by persons with amputation than when performed by control subjects. For this reason, monitoring the cardiovascular response to therapeutic exercise might be expected to enhance the medical and rehabilitative management of dysvascular amputees. In the present study, 31 amputees with peripheral vascular disease underwent continuous noninvasive dynamic cardiovascular monitoring during an initial physical therapy session. The sample had a mean age of 65 yr. There were 20 females. Twenty patients had unilateral below knee amputation. Fifty-two percent had a preamputation history of cardiac disease and six experienced major cardiovascular complications during rehabilitation. After a mean acute hospitalization of 20 days and a mean rehabilitation stay of 36 days, 11 patients were walking independently and 25 were discharged to home. During the monitored physical therapy session, patients achieved a mean maximum heart rate of 113 beats/min, mean maximum blood pressure of 159/81, mean maximum rate-pressure product of 14,546, and mean percent of age-predicted maximal heart rate of 73%. Seventeen (55%) patients demonstrated abnormalities during the monitored session, four of whom had no prior history of heart disease. These changes consisted predominantly of ST-T segment abnormalities, but also included exercise-induced arrhythmias and decreases in blood pressure. Patients with a history of heart disease demonstrated significantly more abnormalities during the monitored session than did those without a history of heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

The elderly amputee with severe chronic obstructive pulmonary disease. Case reports

The case reports describe three elderly amputees with coexisting severe COPD. All three successfully mastered their prostheses and were discharged home able to walk functional distances. This demonstrates that these patients deserve a trial period of rehabilitation in a situation where close medical supervision and optimal medical management are available. Two of our cases died within 5 years, indicating the fragility and poor long-term prognosis of these patients; the third was lost to follow-up.

[Application and evaluation of the VICON system in gait analysis]

By employing the VICON system, segment angular displacement, velocity and acceleration of the lower limbs were achieved from an Above-Knee (A/K) Amputee using a constant friction prosthesis during the swing phase of the gait cycle. By applying computer for data analysis and inputing anthropometric data of the (A/K) Amputee, kinematic trajectory and a stick diagram of lower limbs were obtained. The data were then compared with those obtained from normal subjects. The results showed that the VICON system can provide quantitative analysis of several important parameters in the gait cycle and that it is very helpful in the evaluation and rehabilitation training of abnormal gait.

Practical methods for controlling powered upper-extremity prostheses

Myoelectric pickups (electrodes and processors for detecting the signal that is recorded as an electromyogram) are the most important human-machine interface for controlling powered upper-extremity prostheses. This article presents a simple explanation of myoelectric signal acquisition and then discusses how these signals are used to control the small motors in electric hands, elbows, wrist rotators, and other similar equipment. The less-familiar switch-based and proportional position-sensing controls are also explained. A complete listing of the major suppliers and products available will aid in understanding a discussion of the criteria for using external power instead of, or along with, body power to control and activate prosthetic function.

Current evaluation of hydraulics to replace the cable force transmission system for body-powered upper-limb prostheses

Present body-powered upper-limb prostheses use a cable control system employing World War II aircraft technology to transmit force from the body to the prosthesis for operation. The cable and associated hardware are located outside the prosthesis. Because individuals with arm amputations want prostheses that are natural looking with a smooth, soft outer surface, a design and development project was undertaken to replace the cable system with hydraulics located inside the prosthesis. Three different hydraulic transmission systems were built for evaluation, and other possibilities were explored. Results indicate that a hydraulic force transmission system remains an unmet challenge as a practical replacement for the cable system. The author was unable to develop a hydraulic system that meets the necessary dynamic requirements and is acceptable in size and appearance.

[A myoelectric prosthesis for the forearm amputee]

The authors make a revision of the principles of action of the myoelectric prosthesis for the forearm amputees and describe their components. The indications and contra-indications (French law) are also referred. We can say as a conclusion that the great progress made in prosthesis in the last years were possible on account of synthetic materials and the use of electronics and miniaturised computers. However, their functional possibilities are remote when compared with the human hand. The high costs of this prosthesis are one limitation to its prescription.

[Evaluation of residual function of the hand in its defects]

The authors have worked out a method of evaluation of residual function of the hand. The method is based on successful on successful 25 types of grasping and functional positions which are most commonly occurring in every-day life of correspond to certain professional skills. This method has been used in the examination of 60 patients before surgical treatment, after reconstructive interventions and subsequent prosthetics. The examination has demonstrated that surgical treatment of prosthetics increased the residual function of the hand on the average to 50%. Surgical treatment combined with prosthetics restores the functional abilities of the hand to 3/4 of the normal condition.