Abstract
Background
Indocyanine green angiography (ICGA) is widely used to evaluate flap perfusion in
reconstructive surgery, but the optimal timing for assessment may differ by flap type.
This study compared the perfusion dynamics of perforator and random pattern flaps
in a rat model using ICGA.
Methods
ICGA dynamics were compared between perforator and random flaps in a rat model. Sixteen
Sprague–Dawley rats (275–300 g) were randomly assigned to either a perforator or a
random flap group. A 0.25-mg dose of indocyanine green (ICG) was administered via
the femoral vein, and fluorescence images were acquired at predefined intervals over
4 minutes. Hypoperfusion was defined as fluorescence intensity below 30% of the peak
value. Necrosis was assessed on postoperative day 7. Statistical analyses included
the Mann–Whitney U and log-rank tests with Expectation-Maximization Iterative Convex
Minorant (EMICM) modeling.
Results
In the perforator flap group, the final area of necrosis corresponded to the ICGA-defined
perfusion boundary observed between 10 and 50 seconds postinjection. In contrast,
necrosis in the random flap group aligned with the ICGA-defined perfusion boundary
captured between 30 and 150 seconds. The most accurate time points for necrosis prediction
were 50 seconds for perforator flaps and 150 seconds for random flaps, both demonstrating
statistical significance (p = 0.0028).
Conclusion
ICGA timing requirements differ between flap types. Implementing flap-specific assessment
windows may enhance intraoperative interpretation and reduce false-positive findings.
These findings support the development of flap-specific ICGA protocols to improve
intraoperative decision-making in reconstructive surgery.
Keywords
perfusion - flap - indocyanine
