Development of a Minimally Invasive Method to Quantify
Blood Flow
in the
Dysvascular Transtibial Amputee, 10-R9803
Principal Investigator
Julie M. Pickard
Inclusive Dates: 04/01/08 – 04/01/10
Background - More than 125,000 amputations are performed in the United States annually with a majority occurring below the knee (transtibial). According to the Center for Disease Control and Prevention, in the period from 1980 to 2007, the age-adjusted incidence of diabetes dramatically increased (136 percent), with the vast majority occurring after 1990. With the number of dysvascular patients rising, a steady increase in the number of amputations has resulted. The mechanical stresses induced by use of a prosthetic system can adversely affect residual limb health. It is well understood that daily use of a lower-limb prosthetic can affect circulation and that inadequate circulation will be detrimental to limb health.
Approach - Unfortunately, only a limited amount of research has been done to determine the relationship between prosthetic design/fit and circulation. This is in part due to the limitations of current clinical tools. Understanding residual limb health, such as circulatory changes, as a function of socket suspension design will ultimately promote improved designs, prescriptions, and long-term favorable patient outcomes. Preliminary data taken at The University of Texas Health Science Center at San Antonio was used in this methodology study to demonstrate the applicability of using the gamma-variate and Kety-Schmidt modeling techniques to understand the physiological implication of using an advanced prosthetic system. These models were subsequently used to compare circulatory changes in patients wearing a vacuum-assisted suspension system (VASS) and check-valve socket.
Accomplishments - This research exploited the area of blood flow modeling using positron emission tomography and magnetic resonance imaging to assess limb health in the diabetic amputee. This method was the first to quantify regional muscular blood flow (rMBF) in the lower extremity of amputees and was novel in that the patient wore a socket during data acquisition. Significance in the rMBF after use of the VASS was demonstrated in the residual limb; however, because of the small group size in the study, additional research is necessary to validate these results.
