Preoperative Peroneal Artery Perforator Mapping Using Indocyanine Green Angiography: A Prospective Clinical Trial.

BACKGROUND: Perforator imaging is a prerequisite in preoperative planning of the peroneal perforator flap and the fibula skin island. Although reports indicate that indocyanine green angiography assessment method might be advantageous over conventional ultrasound-based techniques (i.e., Doppler and color duplex), in practice, clear evidence is lacking. Thus, a comparative assessment of the utility of indocyanine green angiography and ultrasound-based techniques in the identification of suitable lower leg skin perforators was performed. METHODS: A prospective clinical cohort study with a series of 12 consecutive patients was conducted to assess indocyanine green angiography, Doppler ultrasound, and color duplex ultrasound techniques for preoperative perforator detection in the lower leg before free fibula flap harvest. Anatomical dissection served as a reference. Parameters measured were perforator spatial distance to the reference (precision), operative time expenditure, and ease of device usage for assessment/outcomes. RESULTS: This study included 12 patients, with a total of 27 perforators. Exhibition of technique sensitivity and positive predictive values were as follows: indocyanine green angiography, 93 percent and 100 percent; Doppler ultrasound, 82 percent and 82 percent; and color duplex ultrasound, 89 percent and 86 percent, respectively. With regard to the indocyanine green angiography technique, the distance to the actual perforator location was significantly shorter, which aided detection and lesser time expenditure during operation. CONCLUSIONS: The indocyanine green angiography technique proved to have high precision, sensitivity, positive predictive value, and easy-to-use capabilities because of its exceptional spatial and temporal information, compared to the conventional, ultrasound-based techniques. Therefore, indocyanine green angiography is superior for preoperative perforator imaging of the lateral lower leg. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.

Effect of Segment Length and Number of Osteotomy Sites on Cancellous Bone Perfusion in Free Fibula Flaps.

BACKGROUND: Indocyanine green (ICG) videoangiography is routinely used to evaluate skin and organ perfusion and to assess patency rates of microvascular anastomoses. This study uses ICG angiography as a novel approach to qualitatively and quantitatively evaluate bone perfusion of microvascular fibula grafts intraoperatively and to assess the effect of fibula segment length and number of osteotomies on bone perfusion. METHODS: All patients planned for mandible reconstruction using a microvascular fibula graft between January 2013 and May 2017 were considered for this study. ICG videoangiography of cancellous bone perfusion was performed using a handheld ICG camera. Videos were analyzed, and a perfusion curve was generated. Peak enhancement, time to peak, slope, and wash-in area under the curve were extracted; rise time, wash-in rate (WiR), and wash-in perfusion index were calculated. Results were statistically analyzed with regard to distal fibula segment length and number of osteotomy sites. RESULTS: Thirty-nine patients (age 59 ± 8 years) were included in the study. Mandible reconstruction was achieved with 1 (n = 15), 2 (n = 13), or 3 (n = 11) fibula segments. The WiR was 6.4 ± 2.3 and 4.4 ± 0.2 before and after proximal osteotomy, respectively. The wash-in perfusion index was 114.2 ± 48.4 before and 84.4 ± 20.0 after proximal osteotomy. Bone perfusion was significantly reduced after additional proximal osteotomies. Both the segment length and number of proximal osteotomies correlated with bone perfusion, with longer segments and fewer osteotomies showing higher perfusion. CONCLUSION: This study demonstrates the feasibility of cancellous bone perfusion analysis using ICG and can serve as a basis for future bone perfusion studies. Additional osteotomies and short segment length negatively affects cancellous bone perfusion of the distal fibula segment in free fibula flaps. The extent to which the observed decrease in arterial inflow to the distal fibula segment affects the further course of healing needs to be addressed in future studies.