I am sure you have experienced the whittling syndrome--performing an amputation at a clean level with healthy and viable soft tissues then several days later seeing progressive ischemic margins eventually requiring revision amputation. Determining how far we cut seems to be anecdotal with some relying on intraoperative appearances of the soft tissues to more quantitative measures with TcPO2 readings, angiographic foot scores, noninvasive arterial exams. Certainly with diabetes healing is affected my more factors than just blood flow, but hypothetically with all other things being equal, what is your study of choice to determine the best amputation level?
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  • Ryan,

    What is your protocol for using the indocyanine green angiography in clinic?

    Who performs the IV stick? Who injects the bolus of dye? What kind of patient monitoring is done? How many trials are performed? How long does the average exam take?

    Thanks for answering. This is something I tried to institute years ago but the testing did not fit easily into our daily patient clinic flow.


  • We have seen good results with indocyanine green angiography showing real time perfusion of the fluorescent dye. This can be done preoperatively in clinic or intra-operatively. 


  • I agree with Dr. Fitzgerald's comments that blood flow is an important factor for healing, but how do you determine what level will an amputation heal? In an ideal situation, you would like to perform one amputation and prevent the patient from having to return to the OR for a revision amputation. Intraoperatively, amputation to clean viable tissue may not have enough cellular perfusion to heal a closure. Angiographic foot scores seems to correlate well with transmetatarsal amputation healing. Some studies indicate that TcPO2 have demonstrated inconsistent association with level of amputation healing. Is there a study of choice, clinical indicator or wisdom from gray hairs that may have some insight?
  • While certainly wound healing is a multi-factorial process, and as such each specific component must be addressed to ensure appropriate wound healing, if I had to pick ONE specific factor as a predictor for wound healing, I would argue that blood supply is most important.

    Evaluation of perfusion both through noninvasive vascular studies such as TcPO2 as well as intraoperative appearance of the wound margins during debridement can all suggest the level at which an amputation should occur, and may suggest the need to attempt vascular intervention prior to wound closure or limb salvage. (At this point it is key to have developed a relationship with a vascular surgeon enlightened enough to attempt more distal bypass surgery and/or endovascular procedures below the ankle.)

    While other factors, such as nutritional status or the presence of infection certainly play a major roll in wound healing, without a adequate perfusion, correcting these factors won't matter, because the cells won't get the the appropriate nutrition without the access via the circulatory system, nor will systemic antibiotics reach the area of infection in the absence of patent flow. In a sense, i feel that the blood supply is the rate limiting step --all other adjustments require it.