Optical coherence tomography for the investigation of skin adaptation in lower limb prosthesis users.

Introduction: Mechanically induced skin breakdown is a significant problem for many lower-limb prosthesis users. It is known that skin can adapt to the mechanical stresses of prosthesis use thereby reducing the risk of breakdown, yet little is understood about the biology behind skin adaptation. This is a proof-of-concept study for the use of novel, noninvasive optical coherence tomography (OCT) imaging techniques to investigate skin adaptation. Methods: Two OCT imaging-based tests were used to evaluate features of the skin that may be involved in adaptation to limb-socket interface stresses. The tests were used to assess the function and structure of the cutaneous microvasculature, respectively. Epidermal thickness was also quantified. Tests were run on three lower-limb prosthesis users in a region of the residual limb believed to be highly stressed within the prosthetic socket. The measurements were compared with measurements taken at a location-matched site on the contralateral limb. Results: Two of three participants demonstrated a faster time-to-peak and larger peakmagnitude reactive hyperemia response in their residual limb compared with their contralateral limb. Two of three participants also demonstrated a larger magnitude vessel density at maximum dilation in their residual limb versus contralateral limb. The epidermal thickness was greater in the residual limb versus contralateral limb for all participants. Conclusions: This study demonstrated the utility of two novel OCT imaging techniques for investigating skin adaptation in users of lower-limb prostheses. If we are able to confirm these findings on a larger subject population, we will better understand the biology behind mechanically induced skin adaptation. These findings, along with the noninvasive OCT imaging methods introduced here, would have the potential to improve clinical practice by enabling the development of rehabilitation techniques and therapeutics to better strengthen skin, thereby reducing the incidence of harmful skin breakdown.