Abstract
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.
Keywords
flap - surgery - fluorescence - imaging - bone perfusion
