Weight Bearing Distribution in Supported Standing: Effectiveness of Commonly-Used Devices

Jill Sparacio, OTR/L, ATP, ABDA, Sparacio Consulting Services

Tina Roesler, MS, PT, ABDA, The ROHO Group

Introduction

It is common in clinical practice to utilize assisted standing and other alternative positioning techniques in an effort to prevent secondary complications of disease and disability. Through clinical observations and subjective reports, many clinicians have supported the use of alternative positioning, specifically assisted standing, without quantitative data to back up their findings. Often, this is due to the difficulty in collecting data and the length of time it may take to carry out relevant studies in the busy clinical setting. In an effort to establish quantitative documentation on the effectiveness of assisted standing devices on providing weight-bearing through the lower extremities, a pressure mapping system was utilized in the clinical setting to record patterns in some of the most commonly utilized standing devices.

Review

In reviewing the limited amount of literature on assisted standing, it is clear that the supposed benefits are widely accepted. The list below details the benefits and drawbacks that have been documented in the literature and by clinicians through observation and experience.

Standing

Benefits: Improves alignment

Pressure relief from sitting surfaces

Improved respiratory abilities

Improved bowel and bladder function

Improved GI function

Maintenance of and increased bone density

Improved head and trunk control

Drawbacks: Fatiguing

Increased pressure at points of support

Difficult to position with contractures

Frequently requires more than one attendant to position

Potential pressure areas: sacrum, knees, scapulas, chest

While this information is consistent throughout the literature, most of the studies are anecdotal, or are in the case study format. This is most likely the result of many issues:

1. The limited amount of funding available for standing frames.

2. The limited amount of funding available for clinical studies.

3. The invasive and potentially expensive techniques needed to measure the parameters necessary to substantiate the claims.

4. The length of time needed to complete a study on only one client.

For example, an increase or maintenance of bone density may take months or years to recognize, and requires procedures such as x-ray to substantiate claims. In an effort to provide clinically relevant data in the mean time, the authors set out to examine a simple component of assisted standing that may be related to maintenance of bone density. The goal was to address pressure relief on the seated surface and to determine the amount of weight bearing that was actually occurring through the lower extremities in a variety of standing frames.

Methods:

Subjects were selected from a group of residents at a long-term care facility for individuals with developmental disabilities. Each subject was in good health and participated in a routine standing program. All subjects had a primary diagnosis of cerebral palsy.

Equipment for the study included a supine stander and a sit-to-stand device. The Xsensor pressure mapping system was used with a custom pad configuration, allowing the pads to be positioned over all potential weight-bearing surfaces. Standard bathroom scales were placed under the feet to record weight measurements.

Each subject was positioned in both types of standers for a period of 15 min. Pressure readings and weights were recorded initially and at minute fifteen. The weight data was compared to actual body weight to determine percentage of weight bearing through the lower extremities and pressure readings were studied to identify potential problem areas.

Results:

In the initial trial phase, four subjects and one able bodied control were tested in both standers. Testing was limited for 2 subjects because the supine stander could not accommodate their fixed knee flexion contractures.

High pressures were recorded in both the supine and sit-to-stand devices on the sacrum and chest. Pressures on the knees were also very high in the sit-to-stand device. On average, 45.2% of body weight was transferred to the lower extremities in the EasyStand, while in the supine stander an average of 35.4% was recorded. The able-bodied control showed 86% and 80% of body weight through the lower extremities in the respective standers.

Conclusions:

While the study is still on going, preliminary results have indicated that weight bearing in assisted standers is affected by numerous factors. These include type of equipment being used, the extent of lower extremity contractures, the ability of clinicians and caregivers to easily and safely position the subjects, and the perceived comfort of the client.

Other considerations that must be acknowledged include reports from caregivers and subjects. During trials, both groups indicated a preference for the EasyStand device over the supine stander. Safety and comfort during transfers were identified as the primary benefits. Furthermore, the EasyStand was able to accommodate moderate to severe lower extremity contractures.

While the initial findings do not indicate a significant amount of weight bearing occurs during assisted standing, further trials must be completed with a larger number of subjects and across different disability groups. The perceived and reported benefits of standing still support the use of assisted standers with the subjects included in the investigation.

REFERENCES:

Dunn, Robert B, et al. Follow-up Assessment of Standing Mobility Device Users. Assistive Technology, 1998; 10:84-93.

Funding Guide for Standing Technology. Altimate Medical, Inc. 1999

Paleg, Ginny, MPT. Beyond Wheelchairs, Using standers, walkers, and gait trainers to improve mobility problems. Long Term Rehab, 2001, pg. 60-68.

Notes: