In recent years, the concept of Medicare Set Aside Trusts (MSA) has evolved in the workers’ compensation law. Medicare Set Aside Trusts are required in certain settlements depending upon specific legal criteria. In those types of cases, the Medicare Set Aside Trust must be approved by the Center for Medicare and Medicaid Services (CMS) before the settlement can be finalized. Experts are retained to evaluate the injured worker’s case, medical condition and history of treatment, and they prepare Medicare Set Aside Evaluations. This evidence is often relied upon during the settlement negotiation process. A Medicare Set Aside Trust imposes an obligation on the injured worker to "set aside" specifically approved settlement funds to be used for ongoing medical treatment that would otherwise have been the responsibility of Medicare. Injured workers must reconcile their Medicare Set Aside expenditures with CMS on a continuing basis.