Vacuum Suspension: Effects on Tissue Oxygenation, Activity and Fit
Condition: Amputation; Diabetes; Leg Injuries; Traumatic Amputations
MeSH terms: Amputation, Traumatic; Leg Injuries
Study type: Interventional

Summary: 
      The fit of the residual limb within a prosthetic socket is a primary concern for many
      amputees. A poor fit can lead to skin irritation, tissue breakdown, and pain. Further,
      amputees with diabetes or vascular dysfunction often have difficulty maintaining healthy
      residual limb tissue; a condition that could be mitigated by the application of negative
      pressure (i.e., vacuum suspension). The aim of this research is to characterize the residual
      limb response to a vacuum suspension system and to measure prosthetic performance in
      comparison to a typical suction suspension system.

      The proposed research plan involves two sets of human subject experiments: (1) prospective,
      randomized cross-over study to quantify performance of a vacuum suspension system as compared
      to a total surface bearing suction socket in terms of pistoning, maintaining limb volume,
      step counts, and subjective measures of fit and (2) measurement of transcutaneous oxygen
      tension as a function of vacuum pressure.
    

Detailed description: 
      A proper fitting prosthetic socket provides the amputee with a comfortable system allowing
      them to pursue many of their desired vocational and recreational goals. Unfortunately, many
      amputees live with an ill-fitting socket and can experience limb pistoning within the socket,
      which in turn may result in skin irritation, tissue breakdown, discomfort, and a reduction in
      activity. One of the key factors affecting fit is intraday residual limb volume changes. For
      an amputee with dysvascular conditions, the implications of a poor fitting socket are
      exacerbated by poor circulation, reduced healing potential and the compressive forces exerted
      by their prosthesis.

      Vacuum suspension systems may have the potential to alleviate these conditions for healthy
      and dysvascular amputees. The purported benefits of vacuum suspension systems include, but
      are not limited to: improved suspension (reduction in the amount of pistoning), maintenance
      of limb volume throughout the day, and increased tissue oxygenation to the residual limb.

      Our first objective is to characterize performance, as related to socket fit, of a vacuum
      suspension system using objective and subjective measures. We will do this by conducting a
      within-subject experiment to measure pistoning in three dimensions while walking, overall and
      regional changes in limb volume before and after a thirty-minute treadmill walk, mobility
      (step counts) and the perception of socket fit (questionnaire) as a function of prosthetic
      prescription (vacuum suspension system vs. total surface bearing suction socket).

      Our second objective is to determine the effect of pressures within a prosthetic socket on
      residual limb transcutaneous oxygen tension (tcpO2) levels. We will conduct laboratory-based,
      in situ testing to determine how the transcutaneous oxygen tension levels, at six sites on
      the residual limb, respond to pressures simulating those within a vacuum suspension system
      and a total surface bearing suction socket.

      The proposed research will allow us to understand how suspension systems influence prosthetic
      socket fit and residual limb tissue health and to formulate a knowledge base on two
      suspension systems providing prosthetists and clinicians the objective data to make better
      prescription decisions. In addition, the methods utilized in this study (e.g., a residual
      limb limb volume scanner and assessing dynamic pistoning) can be used to study current and
      novel suspension systems, liners, and prosthetic socket designs to provide a standard for
      comparison.
    

Intervention name(s): Total Surface Bearing Suction Socket; Vacuum assisted socket system
Intervention type(s): Device; Device
Intervention description(s): Current clinical practice; Novel socket system
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Amputee; Artificial limbs; Gait; Walking