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 – Current

Background - More than 125,000 amputations are performed in the United States annually with a majority occurring below the knee (transtibial). The Center of Disease Control reports that more than 60 percent of all non-traumatic lower-limb amputations occur in people with diabetes. 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. Unfortunately, only a limited amount of research has been done to determine the relationship between prosthetic design/fit and circulation. This is in part because of the limitations of current clinical tools.

Approach - 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. This research exploits the area of blood flow modeling using positron emission tomography and magnetic resonance imaging to assess limb health in the diabetic amputee. This method will be the first to quantify absolute tissue blood flow in the lower extremity of amputees and will be novel in that the patient can wear a socket during data acquisition. The model will be used to compare circulatory changes in patients wearing a vacuum-assisted socket system (VASS) and check-valve socket.

Accomplishments - Data from a pilot study at The University of Texas Health Science Center at San Antonio was used to assess the theoretical application of the proposed Kety-Schmidt tissue blood flow model. Preliminary data has shown that this method can quantify blood flow and edema in the residual limb. The figure shows the blood flow in a patient after exercising their tibialis muscle. The study is currently awaiting Institutional Review Board approval before the clinical study commences. This data will be used as an input to the model to determine if our method yields rates similar to those obtained from traditional methods. In addition, this model will be used to compare pre-VASS and post-VASS measures of blood flow in the residual limb of the dysvascular transtibial amputee.

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