A mathematical risk-benefit analysis of composite tissue allotransplantation

Composite tissue allotransplantation (CTA) represents a surgical technology whose risks and benefits are unclear. This is problematic for clinicians with respect to patient selection and counseling, and for policy makers in evaluating its merits. Our analysis represents a mathematical approach to risk and benefit estimation in CTA.

A Markov model was created to represent clinical and immunological outcomes after CTA. Esthetic outcomes were incorporated into the model by creating a disfigurement-related-disability severity score index based on existing literature. Composite tissue allotransplantation in a 30-year-old male was used as a base case analysis. We compared CTA against autogenous reconstruction as competing strategies. Sensitivity analyses were performed on the effect of preoperative esthetic morbidity and postoperative esthetic outcome.

Our base-case showed CTA to be the preferred strategy-conferring a benefit of 4.47 esthetic-outcome-adjusted life years. Sensitivity analyses showed CTA to be the preferred strategy if the preoperative disability severity score was greater than 5, and if the severity score after autogenous reconstruction was greater than 7.

Our model estimates a theoretical risk-benefit threshold for CTA. The model itself can be refined as clinical experience with CTA grows and can incorporate economic and quality-of-life parameters.