External Volume Expansion in Irradiated Tissue: Effects on the Recipient Site

UMMS Affiliation

Department of Radiation Oncology; Department of Surgery, Division of Plastic Surgery; School of Medicine; Senior Scholars Program

Faculty Mentor

Janice Lalikos, MD

Publication Date


Document Type



Medical Education | Oncology | Plastic Surgery | Radiology


BACKGROUND: External volume expansion prepares recipient sites to improve outcomes of fat grafting. For patients receiving radiotherapy after mastectomy, results with external volume expansion vary, and the relationship between radiotherapy and expansion remains unexplored. Thus, the authors developed a new translational model to investigate the effects in chronic skin fibrosis after radiation exposure.

METHODS: Twenty-four SKH1-E mice received 50 Gy of beta-radiation to each flank and were monitored until fibrosis developed (8 weeks). External volume expansion was then applied at -25 mmHg to one side for 6 hours for 5 days. The opposite side served as the control. Perfusion changes were assessed with hyperspectral imaging. Mice were euthanized at 5 (n = 12) and 15 days (n = 12) after the last expansion application. Tissue samples were analyzed with immunohistochemistry for CD31 and Ki67, Masson trichrome for skin thickness, and picrosirius red to analyze collagen composition.

RESULTS: All animals developed skin fibrosis 8 weeks after radiotherapy and became hypoperfused based on hyperspectral imaging. Expansion induced edema on treated sides after stimulation. Perfusion was decreased by 13 percent on the expansion side (p < 0.001) compared with the control side for 5 days after stimulation. Perfusion returned to control-side levels by day 15. Dermal vasculature increased 38 percent by day 15 (p < 0.01) in expansion versus control. No difference was found in collagen composition.

CONCLUSIONS: External volume expansion temporarily reduces perfusion, likely because of transient ischemia or edema. Together with mechanotransduction, these effects encourage a proangiogenic and proliferative environment in fibrotic tissue after radiotherapy in the authors' mouse model. Further studies are needed to assess these changes in fat graft retention.

DOI of Published Version



Plast Reconstr Surg. 2016 May;137(5):799e-807e. doi: 10.1097/PRS.0000000000002081. Link to article on publisher's site

Journal/Book/Conference Title

Plastic and reconstructive surgery


Oksana Babchenko, Dylan Perry, and Ava Chappell participated in this study as medical students as part of the Senior Scholars research program at the University of Massachusetts Medical School.

Related Resources

Link to Article in PubMed

PubMed ID