Prediction of amputation wound healing with skin perfusion pressure

The purpose of this study was to determine whether laser Doppler skin perfusion pressure (LD-SPP) could accurately predict amputation wound healing.

We studied a total of 62 limbs in 52 patients (28 men and 24 women) with a mean age of 62.2 years (range 34 to 93 years). From this, 39 limbs underwent major amputation (15 above-the-knee, 24 below-the-knee), and 23 limbs underwent minor amputations (4 transmetatarsal and 19 toes). There were five postoperative deaths, leaving a total of 57 limbs available for analysis.

Three of 13 above-knee amputations failed to heal. Twenty-one of 23 below-knee amputations healed. Three of four transmetatarsal amputations failed to heal and eight of 17 toe amputations failed to heal. Binary table analysis showed that an LD-SPP value of 30 mm Hg or greater had a negative predictive value (healing occurred) of 90%. An LD-SPP value of less than 30 mm Hg at the amputation site had a positive predictive value (healing failure) of 75%, (p < 0.001, chi square analysis). For major amputations, negative predictive value was 100%, and positive predictive value was 83%, (p < 0.001). For minor amputations, negative predictive value was 75% and positive predictive value was 66.7%, (p < 0.09).

These data support the use of the LD-SPP test in the selection of major amputation level consistent with healing in ischemic limbs. Further study of the value of this parameter in the determination of minor amputation wound healing is necessary.