# Inter‐ and Intra‐Rater Reliability of Myotonometric Assessment of the Mechanical Properties of Caesarean Section Scar Skin Using the MyotonPRO With an L‐Shaped Probe

## TL;DR

This study shows that the MyotonPRO device with an L-shaped probe reliably measures the mechanical properties of C-section scar skin across and within raters.

## Contribution

The study provides new reliability data for using the MyotonPRO with an L-shaped probe to assess C-section scar skin.

## Key findings

- Inter-rater reliability was good to excellent (ICC = 0.75–0.90).
- Intra-rater reliability was moderate to good, with lower ICCs for consecutive-day measurements.
- SEM, MDC, and CV values confirmed lower measurement error between raters than within raters.

## Abstract

Myotonometry is a noninvasive method for assessing the mechanical properties of soft tissues, including muscles and skin. The L‐shaped probe, designed specifically for skin assessment, may be useful for evaluating caesarean section (C‐section) scars. However, reliability data for MyotonPRO measurements of C‐section scars with this probe are limited. This study aimed to evaluate the inter‐rater and intra‐rater reliability of measuring the mechanical properties of C‐section scar skin using the MyotonPRO with the L‐shaped probe.

Twenty‐five women (23–42 years) with C‐section scars were examined. Two raters conducted the myotonometric assessments over two consecutive days. Measurements were taken with the participant supine, using the L‐shaped probe at six points around the scar (three above, three below; positioned at the scar's endpoints and centre), each tested in three directions (right, left and upward/downward). Reliability was analysed using the intraclass correlation coefficient (ICC) with 95% confidence intervals (CIs), the standard error of measurement (SEM), minimal detectable change (MDC), coefficient of variation (CV) and Bland–Altman plots.

Inter‐rater reliability was good to excellent (ICC = 0.75–0.90), while intra‐rater reliability was moderate to good, with slightly lower ICCs for consecutive‐day measurements. SEM, MDC and CV values supported these findings, showing lower measurement error and narrower variability ranges between raters than within repeated measurements by the same rater.

The MyotonPRO with the L‐shaped probe provides reliable inter‐ and intra‐rater measurements of C‐section scar skin mechanical properties, making it a valuable tool for scar evaluation.