In GA & FC Wagman, Inc. v. Workers' Compensation Appeal Board (Aucker), 785 A.2d 1087 (Pa. Cmwlth. 2001), the employer issued a notice of compensation payable accepting liability for an exacerbation of pseudoarthrosis. In a subsequent termination proceeding, the employer's medical witness testified that the claimant sprained muscle ligaments in his back during the work injury and that this sprain had resolved. The medical witness acknowledged possible pseudoarthrosis, but he opined that it was of no consequence. The Workers' Compensation Judge (WCJ) granted the employer's termination petition, but the Workers' Compensation Appeal Board (WCAB) reversed, concluding that the employer's medical witness failed to testify that the claimant was fully recovered from pseudoarthrosis, the injury acknowledged by the Notice of Compensation Payable (NCP). In affirming the WCAB, the court in Wagman held that the testimony of a medical expert who does not believe that the injury acknowledged in the NCP ever occurred is not sufficient to support a termination of benefits. The court explained that sections 407 and 413(a) of the Workers' Compensation Act (Act), Act of June 2, 1915, P.L. 736, as amended, 77 P.S. 731, 771, prohibit parties from relitigating the nature of an accepted injury without first following the proper procedure, which is to file a review petition seeking to have the description of the injury changed.