title: A novel noncontact method to assess the biomechanical properties of wound tissue.
abstract: A novel noncontact optical coherence tomography based air-jet indentation system was developed for characterizing the biomechanical properties of soft tissue in a noncontact way. This study aimed to measure the stiffness of diabetic foot ulcer tissues by using this air-jet indentation system, and examining the test/retest reliability. Eight subjects with diabetes (seven males, one female), with a total of 10 foot ulcers between them, participated in the study. A total of 20 measuring sites located at the central wound bed (n=10) or peri-ulcer areas (n=10), respectively, were evaluated with the air-jet indentation system. Four cycles of loading and unloading, each with a duration of approximately 36 seconds at an indentation rate of 0.08 mm/s, were carried out for each indentation trial. The test/retest reliability was examined at all measuring points. The average stiffness coefficient of the peri-ulcer area (mean ± SD: 0.47 ± 0.15 N/mm) was significantly larger than that of the central wound bed area (mean ± SD: 0.35 ± 0.23 N/mm; p=0.042). A high value for test/retest reliability was shown (intraclass correlation coefficient: 0.986; Pearson's correlation: r=0.972, p<0.001). Our preliminary findings showed that the peri-ulcer area had greater stiffness than the central wound bed. This greater magnitude of hardness and inelasticity at the peri-ulcer region may scatter part of the contractile forces for wound contraction during the healing process. We found the novel air-jet system to be a reliable tool for characterizing the stiffness of soft tissues around the wound in a noncontact way.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Clare Y L
authors.initials: CY
authors.lastname: Chao
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Zheng
authors.forename: Gladys L Y
authors.initials: GL
authors.lastname: Cheing
mesh_terms: D000368:Aged; D000388:Air; D001696:Biomechanical Phenomena; D017719:Diabetic Foot / Q000503:physiopathology*; D004548:Elasticity; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D041623:Tomography, Optical Coherence / Q000379:methods*; D014945:Wound Healing / Q000502:physiology*