Auto Control of Volume Management for Limb Loss
Study Details
Study Description
Brief Summary
The aim of this research is to create a prosthetic system that will automatically adjust the fit of the socket and create a well-fitting prosthesis for people with leg amputations who experience volume fluctuations when using their prosthesis.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
Detailed Description
People with lower limb amputations often experience daily changes in the size (volume) of their residual limb. These daily changes can cause a prosthesis to fit poorly. They can also cause limb health problems including skin breakdown and injury to deeper tissues. Prosthetic socket systems that accommodate limb volume changes can help address these issues, but they require users to make adjustments throughout the day.
The objective of this research is to develop and test an automatically-adjusting prosthetic socket system for prosthesis users. The system integrates with a range of adjustable socket technologies, including those that are commercially available. The system allows small size adjustments for both tightening and loosening the socket. In early aims of the study, the prosthesis will be adjusted manually, but can be controlled remotely, eliminating the need to remove the prosthesis or bend down to make adjustments. The system will later be enhanced to automatically change the fit of an adjustable socket at the appropriate times, without distracting the user. We hypothesize that this system will help to maintain consistent limb fluid volume while the prosthesis user is wearing the socket and that socket fit will be improved. The system functions by continuously collecting measurements from sensors within the socket and uses small motors to control adjustable panels in the socket wall.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Adjustable Socket - Researcher Controls An adjustable socket is tested where researchers control the adjustments. This arm focuses on socket size adjustments while walking. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
| Experimental: Adjustable Socket - Participant Controls An adjustable socket is tested where the study participant controls the adjustments. This arm focuses on socket size adjustments while walking. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
| Experimental: Adjustable Socket - Automatic Controls An adjustable socket is tested where a control system is used to automatically control the adjustments. This arm focuses on socket size adjustments while walking. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
| Experimental: Stress-Sensing Liner An adjustable socket is tested in addition to a prosthetic liner with embedded stress sensors to measure mechanical stresses as the socket is adjusted. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
| Experimental: Release/Recovery - Researcher Controls An adjustable socket is tested where researchers control the adjustments. This arm focuses on a socket release and recovery mechanism that allows for full or partial doffing of the socket while seated. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
| Experimental: Release/Recovery - Participant Controls An adjustable socket is tested where the study participant controls the adjustments. This arm focuses on a socket release and recovery mechanism that allows for full or partial doffing of the socket while seated. |
Device: Adjustable socket
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
|
Outcome Measures
Primary Outcome Measures
- Change in Limb Volume [Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.]
Limb volume fluctuations will be measured in real-time as socket adjustment strategies are tested. This will be accomplished using a portable bioimpedance device with thin sticky electrodes that are placed on the residual limb. Specifically, the change in limb volume will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
- Change in Limb Movement [Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.]
Limb movement within the socket will be measured as socket adjustment strategies are tested. It will be used as an indicator of how well the socket is fitting (loose, tight, etc). The measurement will be made using an inductance sensor that is placed in the socket which measures the displacement of a sensor patch on the prosthetic liner. Specifically, the change in limb movement will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Eligibility Criteria
Criteria
Inclusion Criteria:
-
18 years of age or older
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Unilateral transtibial amputee
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At least 6 months post-amputation
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Wear prosthesis at least 3 hours per day
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Use an elastomeric (i.e. gel) liner
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K3 or higher Medicare Functional Classification Level
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Able to walk continuously with prosthesis for at least 5 minutes at a time, sit, stand, and step up a height of 5.0 cm.
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Residual limb of 9.0 cm or longer
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Experience problems with volume fluctuations that affect their prosthetic socket fit
Exclusion Criteria:
- Participants experiencing skin breakdown on enrollment will be excluded, but can enter after having been free of clinically visually-apparent skin breakdown for two weeks.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | University of Washington Bioengineering | Seattle | Washington | United States | 98195 |
Sponsors and Collaborators
- University of Washington
Investigators
- Principal Investigator: Joan E Sanders, PhD, University of Washington
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- STUDY00001779