Validity and reliability of three-dimensional costal cartilage imaging for donor-site assessment and clinical application in microtia reconstruction patients: A prospective study of 22 cases.

OBJECTIVES

This study assesses the ability to reconstruct costal cartilage images by using three-dimensional visualisation software (Mimics) based on semi-automated segmentation algorithm and to investigate its reliability and validity with an anthropometric analysis.

DESIGN

Observational prospective study.

SETTING

Plastic surgery department of a tertiary hospital.

PARTICIPANTS

Twenty-two microtia patients who underwent autologous ear reconstruction.

MAIN OUTCOME MEASURES: Preoperative thoracic computed tomography data were processed to Mimics software for three-dimensional costal cartilage imaging. The length, width, thickness and volume of the 9th costal cartilages were calculated from these images and compared with the direct measurements (DM) obtained intraoperatively.

RESULTS

The intra-examiner reliability and inter-examiner reliability were high in terms of all four measurements (intraclass correlation coefficients, ICC: 0.876-0.984). There were no significant differences between image-based anthropometry and DM in the linear measurements except for the volume (P < .05). The mean volume calculation error of Mimics was -0.08 ± 0.13 mL. No correlation was found between the anthropometric variables and the absolute errors (P > .05). Furthermore, Bland-Altman plots were used to evaluate the agreement between the two methods.

CONCLUSIONS

Despite a very small error was found in volume calculation, Mimics software was accurate and reliable in linear calculation. Three-dimensional costal cartilage imaging was found to be an efficient tool for morphological evaluation of costal cartilages. We believe that with the application of individualised cartilage models based on three-dimensional printing, the use of customised ear framework carving will be practicable in surgical training.