Diagnostical accuracy of hyperspectral imaging after free flap surgery


  • Torsten Schulz Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany
  • Rima Nuwayhida Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany
  • Khosrow Siamak Houschyar Hautzentrum Köln, Cologne, Germany
  • Stefan Langer Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany
  • Lukas Kohler Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany; Division of Hand-, Plastic- and Aesthetic Surgery, University Hospital Munich, Munich, Germany




Hyperspectral imaging, free flap, malperfusion, venous congestion


Microsurgical free-tissue transfer has been a safe option for tissue reconstruction. This study aimed to analyze the diagnostic accuracy of hyperspectral imaging (HSI) after free-tissue transfer surgery. From January 2017 to October 2019, 42 consecutive free-flap surgeries were performed, and their outcomes were analyzed via HSI. Clinical examination of free-flap perfusion was initially performed. Clinical examination findings were subsequently compared with those of HSI. Potential venous congestion with subsequent necrosis was defined as a tissue hemoglobin index of ≥53%. Student’s t-test was used to compare the results of the analysis. The evaluation of sensitivity and specificity for flap failure detection was time dependent using the Fisher’s exact test. A p-value of ≤0.05 was considered statistically significant. Microsurgical tissue transfer success rate was 84%. Seven patients presented with venous congestion that caused total flap necrosis. Overall, 124 assessments were made. HSI accurately identified 12 out of 19 pathological images: four as false positive and seven as false negative. The sensitivity and specificity of HSI were 57 and 94%, respectively, compared to those of clinical examination that were 28 and 100%, respectively, within 24 h following tissue transfer. The sensitivity and specificity of HSI were 63 and 96%, respectively, compared to those of clinical examination that were 63 and 100%, respectively, within the first 72 h. A tissue hemoglobin index of ≥53% could predict venous congestion after free-flap surgery. HSI demonstrated higher sensitivity than clinical examination within the first 24 h; however, it was not superior compared to clinical findings within 72 h.


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How to Cite

Schulz, T., Nuwayhida, R., Houschyar, K. S., Langer, S., & Kohler, L. (2023). Diagnostical accuracy of hyperspectral imaging after free flap surgery. Journal of Plastic Surgery and Hand Surgery, 58, 48–55. https://doi.org/10.2340/jphs.v58.7140



Original Research Articles