Follow-up study on the use of leg braces issued to spinal cord injury patients

Improving stand-to-sit maneuver for individuals with spinal cord injury

Background

Users of neuroprostheses employing electrical stimulation (ES) generally complete the stand-to-sit (STS) maneuver with high knee angular velocities, increased upper limb support forces, and high peak impact forces at initial contact with the chair. Controlling the knee during STS descent is challenging in individuals with spinal cord injury (SCI) due to the decreasing joint moment available with increased knee angle in response to ES.

Methods

The goal of this study was to investigate the effects of incorporating either (1) a coupling mechanism that coordinates hip and knee flexion or (2) a mechanism that damps knee motion to keep the knee angular velocity constant during the STS transition. The coupling and damping were achieved by hydraulic orthotic mechanisms. Two subjects with SCI were enrolled and each served as their own controls when characterizing the performance of each mechanism during STS as compared to stimulation alone. Outcome measures such as hip-knee angle, knee angular velocity, upper limb support force, and impact force were analyzed to determine the effectiveness of the two mechanisms in providing controlled STS.

Results

The coordination between the hip and knee joints improved with each orthotic mechanism. The damping and hip-knee coupling mechanisms caused the hip and knee joint ratios of 1:1.1 and 1:0.99, respectively, which approached the 1:1 coordination ratio observed in nondisabled individuals during STS maneuver. The knee damping mechanism provided lower (p < 0.001) and a more constant knee angular velocity than the hip-knee coupling mechanism over the knee range of motion. Both the coupling and damping mechanisms were similarly effective at reducing upper limb support forces by 70 % (p < 0.001) and impact force by half (p ≤ 0.001) as compared to sitting down with stimulation alone.

Conclusions

Orthoses imposing simple kinematic constraints, such as 1:1 hip-knee coupling or knee damping, can normalize upper limb support forces, peak knee angular velocity, and peak impact force during the STS maneuvers.

Clinical experience with functional electrical stimulation-assisted gait with Parastep in spinal cord-injured patients

STUDY DESIGN

Clinical evaluation of the Parastep method, a six-channel transcutaneous functional electrical stimulation device, in spinal cord-injured patients.

OBJECTIVES

To investigate the motor performances of this new technique regarding energy expenditure and to evaluate its advantages and limitations, especially in social activities involving ambulation.

METHODS

This study was conducted in 15 thoracic spine-injured patients. The lesion was complete except in two patients. The gait ability and the functional use were judged clinically. Energy cost was evaluated from heart rate, peak oxygen uptake, and lactatemia.

RESULTS

Thirteen patients completed the training (mean: 20 sessions) and achieved independent ambulation with a walker. The mean walking distance, without rest, was 52.8 +/- 69 m, and the mean speed was 0.15 +/- 0.14 m/sec. One patient with incomplete lesion, who had been nonambulatory for 8 months after the injury, became able to walk without functional electrical stimulation after five sessions. The follow-up was 40 +/- 11 months. Five patients pursued using functional electrical stimulation-assisted gait as a means of physical exercise but not for ambulation in social activities. The patients experienced marked psychological benefits, with positive changes in their way of life. In three subjects, a comparison of physiologic responses to exercise between a progressive arm ergometer test and a walking test with the Parastep (Sigmedics, Inc., Northfield, IL) at a speed of 0.1 m/sec was performed, showing that the heart rate, the peak oxygen uptake, and lactatemia during gait were close to those obtained at the end of the maximal test on the ergometer.

CONCLUSIONS

In spite of its ease of operation and good cosmetic acceptance, the Parastep approach has very limited applications for mobility in daily life, because of its modest performance associated with high metabolic cost and cardiovascular strain. However, it can be proposed as a resource to keep physical and psychological fitness in patients with spinal cord injury.

The reciprocating gait orthosis: long-term usage patterns

OBJECTIVE

To investigate the frequency of nonusage of the reciprocating gait orthosis (RGO) in 85 patients supplied between 1986 and 1993. Reasons for nonusage and usage patterns were examined.

DESIGN

Nonusage was determined from patient records and clinical knowledge. Patients were surveyed using a detailed questionnaire to produce information on usage patterns.

SETTING

All patients had been treated as hospital outpatients.

PATIENTS

Most patients had congenital or acquired spinal cord lesions. Postal questionnaires were sent to 81 patients 5 to 55 years of age (mean 20.4 years). Thirty-five patients replied.

RESULTS

At a mean follow-up of 5.4 years, 71% of patients were classified as nonusers. Of the 35 respondents to the questionnaire (mean follow-up 5.5 years, range 4 to 7 years), 20 patients were nonusers. Median usage was 27 months in patients under age 18 and 24 months in adult patients. Significant differences were observed between nonusers and users in the areas of perception of the RGO as a functional tool, independence, and reliability and between the adult and the under 18 groups in the areas of weekly usage, function, independence, and reliability.

CONCLUSION

The high level of nonusage of the RGO has implications for prescription practice. Identifying reasons for nonusage and acknowledging differences in use between age groups will help in patient assessment.

Therapeutic FES: from rehabilitation to neural prosthetics

The purpose of this paper is to review the therapeutic applications of electrical stimulation and to focus on functional neuromuscular electrical stimulation (FES), which is the production of useful muscle contractions for joint stability and limb movement. The use of FES to improve patient function during the recovery period after illness or injury and the transition to FES neural prosthetic systems for patients who do not fully recover will be discussed. Emphasis will be given to the maintenance of posture and the production of purposeful movement from the perspective of technologies and clinical strategies that are available today and from the perspective of those technologies that have the potential for transfer to community health care in the near future.