Objective measurement of limb perfusion by dermal fluorometry. A criterion for healing of below-knee amputation

Quantitative fluorometry has been recommended as an accurate adjunct to clinical judgment in the preoperative assessment of lower-extremity amputation level. In this prospective study of 56 patients who had below-knee amputation, clinical judgment was used as the sole criterion for site selection. Quantitative fluorometry was compared with clinical judgment in a prospective, blinded study. All patients were studied before amputation with administration of intravenous fluorescein. Fifteen minutes after injection, objective measurement of dye fluorescence was performed at multiple sites with a quantitative fluorometer, and a dye fluorescence index was derived. All limbs undergoing amputation were ischemic, manifested by rest pain, nonhealing ulcers, or gangrene. Five patients (8.7%) failed to heal at the below-knee level. The mean dye fluorescence index for the group that healed was 81 +/- 51 (range, 13 to 259) and for the group that failed to heal, 110 +/- 49 (range, 70 to 195). Objective measurement of fluorescein perfusion did not correlate with amputation healing at the below-knee level in our patient population.