Effects of low-intensity pulsed ultrasound on soft tissue micro-circulation in the foot

Low-intensity pulsed ultrasound (LIPUS) has been shown to accelerate bone healing and is considered to increase blood flow. The aim of this study was to assess changes in micro-circulation of the foots' soft tissue in response to LIPUS intervention. We hypothesised improved micro-circulation in response to LIPUS.

Micro-circulation was assessed in 2 mm and 8 mm-deep skin of 50 healthy volunteers using non-invasive laser-doppler spectrophotometry (O2C-device). Measurements were performed before LIPUS-intervention (pre), directly after intervention (post) and 20, 40 and 60 minutes after LIPUS.

All parameter of micro-circulation increased directly after LIPUS intervention at 8 mm depth. Participants with a low pre-intervention flow showed the largest changes (p < 0.001) with an increased post-flow of 38%. SO₂ levels increased significantly after intervention (p = 0.045) and decreased after 60 minutes in comparison to pre-intervention status. rHb levels after 60 min were significantly higher in comparison to pre-intervention levels.

In healthy volunteers, low-intensity pulsed ultrasound led to significant short-term changes in microcirculation of the foot. Younger subjects with a low pre-flow level and smokers showed a higher potential to increase blood flow after LIPUS.