Assessment of tissue viability in complex extremity injuries: Utility of the pyrophosphate nuclear scan

Background,: Extensive extremity injuries often require difficult decisions regarding the necessity for amputation or radical debridement. During the past decade, we have used technetium-99 pyrophosphate (PyP) scanning as an adjunct in this setting. This study was performed to assess the accuracy of PyP scan in predicting the need for amputation in relation to clinical, op erative, and pathologic findings. Methods: Review of our computerized registry identified lr patients (10 men , ape 36.1 +/- 14.9 years) admitted from 1990 to 1999 who underwent PyP sca n. Using operative and pathologic findings, accuracy of the PSP scan was gr aded as supporting or refuting the clinical assessment of the need for ampu tation. Results: Eight patients suffered high-voltage electrical injuries, one had severe Frostbite, and two suffered soft-tissue infections, In most cases, P yP scan showed clear demarcation of viable and nonviable tissue, verifying the need for amputation (positive); those that demonstrated viable distal t issues confirmed at operation were considered negative. PyP scan had a sens itivity of 94%, a specificity of 100%, and an accuracy of 96% in this setti ng. Conclusion: Technetium-99 PSP scanning is a useful adjunct in predicting th e need for amputation in extremities damaged by electrical injury, frostbit e, or invasive infection, In addition, by providing an objective "picture" of extremity perfusion, PyP scans can be helpful in convincing patients of the need for amputation.