Biomechanical Characterization of Skin Properties Using Impact Based-Analysis Method (IBAM)

Skin palpation remains, alongside visual inspection, the main clinical tool used to detect cutaneous abnormalities. However, palpation is a subjective, operator-dependent examination with limited sensitivity. There is currently no simple, real-time, low-cost, non-invasive tool available in routine clinical practice to objectively characterize the mechanical properties of skin tissue. The Impact-Based Analysis Method (IBAM) is a non-invasive biomechanical characterization technique developed by the MSME laboratory (Modélisation et Simulation Multi-Échelle, Université Paris Est Créteil) and the Mondor Institute for Biomedical Research (IMRB). It measures the mechanical response of soft tissue to a small mechanical impact, producing a quantitative indicator (Δt) that reflects local tissue stiffness. The reproducibility and sensitivity of this method have previously been demonstrated in preclinical models. This study aims to evaluate whether IBAM can distinguish malignant cutaneous tumors (basal cell carcinoma, squamous cell carcinoma, melanoma) from healthy surrounding skin based on their mechanical properties, and to characterize how these mechanical properties evolve from the tumor center toward clinically healthy margins. This is a prospective, single-center, ex vivo cohort study conducted at the Department of Plastic Surgery, Henri Mondor University Hospital (AP-HP), France. Patients undergoing surgical excision (with margins) for a suspected malignant cutaneous tumor will be included. Immediately after surgical excision, and before the specimen is sent for standard pathological examination, IBAM measurements will be performed ex vivo at three locations on the surgical specimen: the center of the tumor, the near peri-lesional area, and the distant peri-lesional area (presumed healthy margin). This additional step does not modify the patient's usual surgical or diagnostic management and does not require any additional intervention on the patient. The primary objective is to compare the IBAM-derived mechanical indicator (Δt) between malignant tissue and healthy tissue, using paired measurements from the same surgical specimen. The secondary objective is to describe the progressive change in mechanical properties from the tumor center to the healthy margin, which may help define more objective surgical safety margins in the future. A total of 10 patients will be included, based on a sample size calculation for a paired comparison (α = 5%, power = 80%). Statistical analysis will use paired Student's t-test or Wilcoxon signed-rank test, depending on data distribution (assessed by Shapiro-Wilk test). This research does not fall under the French "Loi Jardé" framework for research involving the human person, as it involves no additional intervention beyond standard care. It complies with the CNIL reference methodology MR-004. Patients receive individual written information and provide written consent or non-opposition prior to inclusion. Data are pseudonymized and securely stored. If confirmed, this method could provide surgeons with a simple, rapid, and objective tool to help differentiate malignant from healthy skin tissue intraoperatively, and to better define resection margins, with the ultimate goal of improving the surgical management of cutaneous malignancies.