An animal experiment study on the application of indocyanine green angiography in the harvest of multi-angiosome perforator flap

Abstract

Background: This study sought to explore the application value of indocyanine green angiography (ICGA) in the harvest of multi-angiosome perforator flap and the effect of low molecular weight heparin (LMWH) on the survival of postoperative flap.

Methods: Twenty-four SD male rats were selected to construct a three-angiosome perforator flap model with the unilateral iliolumbar artery perforator. They were randomly divided into two groups: the control group was injected with indocyanine green (ICG) into the femoral vein during the operation, and the fluorescence signal was collected and quantitatively analyzed using Real-Time Image Guided System to determine the intraoperative fluorescence imaging length. The experimental group was injected subcutaneously with LMWH (400 U/kg) after 0.5 h postoperatively, and the control group was injected with the same amount of normal saline. The injection was repeated at the same time each day from 0 to 7 days postoperatively. After the flap was sutured in situ, ICGA was performed at 0, 1, 3, 5, and 7 days postoperatively to observe the vascular structure of the two groups of flaps. The flap survival length of the control group was counted at 7 days postoperatively, and the correlation between the intraoperative fluorescence imaging length and the survival length at 7 days postoperatively was calculated. The proportion of distal necrosis of the flaps between the two groups was compared at 7 days postoperatively.

Results: The average length of intraoperative fluorescence imaging in the control group was 6.29±0.50 cm, and the survival length of the flap at 7 days postoperatively was 8.24±0.52 cm. The actual survival length was higher than the intraoperative fluorescence imaging length, with a ratio of 1.31±0.08. The difference was statistically significant (P<0.05). At 7 days postoperatively, the flap necrosis ratio of experimental group and control group were 10.92%±1.30% and 19.11%±1.19%, and the flap necrosis ratio of experimental group was lower than that of control group (P<0.001).

Conclusions: ICGA can locate the position of perforator, and can be used to predict and observe the length of distal survival of multi-angiosome perforator flap postoperatively. LMWH can promote the distal survival of flap and reduce flap necrosis.

Keywords: Indocyanine green angiography; angiosome; limit length; low molecular weight heparin; perforator flap.

Figure 1

Method for measuring intraoperative fluorescence imaging length.

Figure 2

Flap design and the harvest of the 3-angiosome perforator flap. (A) The location of the perforator; (B) flap design; (C) three perforators upon flap elevation (arrow); (D) flap harvest based on the iliolumbar perforator (arrow).

Figure 3

Intraoperative flap fluorescence imaging. (A) Merged mode; (B) fluorescence mode.

Figure 4

Gross observation of flaps at postoperative day 7. (A) Gross observation of a flap in the experimental group; (B) gross observation of a flap in the control group.

Figure 5

Comparison of flap necrosis between the 2 groups. ***P<0.001.

Figure 6

Linear fitting analysis of the survival length of the flap at postoperative day 7 and the length of intraoperative fluorescence imaging.

Figure 7

Analysis of blood supply of the flap postoperatively. (A) Analysis of blood circulation after flap surgery in the experimental group; (B) analysis of blood circulation after flap surgery in the control group.