Subcutaneous Injection of SVF in Combination with HBOT Improves Viability of Unfavorably Designed Cutaneous Flaps

Purpose

Burn and soft tissue reconstruction is inherently complicated by ischemia and reperfusion injury. Efforts to minimize these deleterious effects include meticulous surgical design, minimizing the ischemic period and optimizing vascularity.¹ Animal trials have documented the independent healing benefits of hyperbaric oxygen treatment (HBOT) and stem cell delivery in cutaneous flaps.^2,3Yet, to our knowledge there are no studies investigating both modalities concurrently. In this study, we explored the potential complementary effects of HBOT and stem cell delivery in tissue flap preconditioning. 

Methods

We designed a randomized controlled trial assessing the effects of HBOT and stromal vascular fraction (SVF) delivery on flap survival in a guinea pig animal model.⁴Of the first twenty-four guinea pigs, six animals received neither HBOT nor injections and six guinea pigs underwent HBOT only without injections. Of the remaining 12 guinea pigs, six animals received only SVF or saline injections in the absence of HBOT preconditioning. The final six animals received autologous SVF injections or saline injections followed by four consecutive HBO treatments. In order to enhance clinical relevance, an additional group of 6 guinea pigs underwent HBOT prior to SVF or saline injections. Thereafter, an unfavorably designed cutaneous flap was elevated and clinically assessed via study-blinded observer, as well as by quantification of TUNEL-positive cells.

Results

Distal necrosis of the tissue flap was most often observed in the no intervention group (72.8% of the flap, p < 0.001), similar to tissue flaps treated with HBO only (62.9%, p = 0.036) and SVF injections (46.7%, p = 0.013). The most significant difference occurred in the combination HBO and SVF delivery group, where distal necrosis was only visible in 24.6% of the flap (p < 0.05). Most notably, SVF delivery immediately prior to flap elevation further minimized distal necrosis of the flap to 18 percent. These findings were mirrored by the TUNEL assay, indicating the highest percentage of cell death in the no intervention and HBO only groups (p < 0.05).

Conclusions

Findings not only indicate that combining HBO treatment and SVF improves flap viability, they also suggest that it may be more appropriate to deliver SVF at the time of tissue elevation, providing a more clinically relevant way to treat these patients.