Wound Bed Tissue Oxygenation Differences across Angiosomes of the Foot

Angiosome concept states that anatomic blocks of tissue are fed by named arteries. In the foot, almost the entire plantar surface is fed by branches of the posterior tibial artery. Plantar wounds are difficult to heal due to myriad reasons including biomechanics, repetitive microtrauma, and local hypoperfusion. We used hyperspectral imaging to evaluate whether there was a greater change in the tissue oxygen saturation (StO2) of plantar wounds versus those in other angiosomes after application of an amniotic membrane.

Hyperspectral images from patients enrolled in a prospective cohort study for an amniotic membrane were analyzed. All patients had an ankle brachial index >0.5, foot ulcers more than 30 days old, and were offloaded with removable cast boot or total contact cast. Images were taken after debridement and prior to the application of the amniotic membrane at baseline visit and again 2 weeks later. Twenty one paired images were compared to assess differences in the tissue oxygen saturation of the wound bed.

Fourteen plantar wounds (7 medial, 7 lateral, 66.7%) were compared to 7 wounds in other angiosomes (5 anterior tibial, 2 peroneal, 33.3%). Plantar wounds showed an average increase in StO2 of +4.07 ± 12.68%. Wounds from other angiosomes showed an average decrease of -1.12 ± 15.21%.

Wounds in areas fed by the posterior tibial artery showed increased tissue oxygenation compared to those fed by the anterior tibial or peroneal arteries. This effect may be due to the larger size of the posterior tibial vessels and branches. The increase may only remain for a short term but further investigation is warranted as this analysis may be beneficial in clinically optimizing wounds for faster closure.

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