Using Intraoperative Tissue Perfusion Assessment to Identify Areas at Risk for Complication in Lower Extremity Major Amputations
Joseph Tingen, Matt Low, Chris Carsten
Prisma Health, Greenville, SC
BACKGROUND: An objective measurement has been sought to minimize the risk for wound complications associated with lower limb major amputation. Prior adjuncts have failed to adequately and accurately predict these complications. Surgeon experience and clinical acumen has remained the mainstay of decision making for amputation site and closure technique in the absence of objective measurements. Lower extremity major amputations have wound complication rates of nearly 20% which is often related to infection or ischemia. These complications can cause morbidity up to 35% and mortality ranging from 4-22%. The purpose of the study was to evaluate the utility of the Stryker SPY PHI system (Kalamazoo, MI) for intra-operative limb perfusion to predict sites of wound healing complication in lower extremity amputation. METHODS: A prospectively collected database of patients (n=39) who had intra-operative indocyanine green (ICG) tissue perfusion assessment of their major amputation (above knee amputation (AKA), below knee amputation (BKA), transmetatarsal amputation (TMA) stump from Feb 2021 to July 2021 was created. Intra-operative perfusion images were saved to the patients medical record. Three milliliters of ICG was given intravenously and the amputation closure was assessed using quantitative perfusion (QP) measurements. Surgeons were not encouraged to change the wound closure based on SPY results during this early cohort evaluation since this was observational. SPY QP percent measurements were reviewed to determine what QP percentage is ideal to predict areas of poor wound healing. Re-operation, re-admission and death rates were recorded as well. RESULTS: Over a six month period, thirty-nine non-traumatic major amputations were performed. Thirty one (79%) patients healed without complication. Eight patients (21%) did not heal due to stump infection (n=2; 5.1%) or ischemic skin necrosis (n=6; 15.3%). Three of 15 (20%) AKA patients, 2 of 20 (10%) BKA patients, and 3 of 4 (75%) TMA patients had complications. The location of the complication corresponded to the area of intra-operative low SPY QP in seven cases (87.5%). Average SPY QP for patients that healed was 71%. Average SPY QP for patients that developed complication was 29%. Four patients (10.2%) with infection or necrosis required re-operation. Original level of amputation was salvaged in two patients, but higher level of amputation was required in the two other patients. Four (10.2%) of the thirty-nine patients were dead at final chart review. The table summarizes the SPY results.CONCLUSIONS: Intra-operative ICG tissue perfusion assessment predicts areas of wound complication and healing potential for lower limb major amputation.
| Highest QP | Lowest QP | Average QP | |
| Healed (n=31) | 100% | 40% | 71% |
| Complication (n=8) | 45% | 17% | 29% |
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