concurring and dissenting.
St. Mary’s Home of Erie (Employer) filed two separate petitions, one to terminate benefits and the other to review the parties’ agreements for compensation1, and Dorothy Stadtmiller (Claimant) filed a petition to review medical treatment. The decision and order of the Workers’ Compensation Judge (WCJ), which was affirmed by the Workmen’s Compensation Appeal Board (Board), denied both petitions of Employer and granted the petition of Claimant along with an award of costs. I concur insofar as the majority reverses the award costs as set forth in the bill of costs; however, I disagree with the majority’s affirmance in all other respects and accordingly dissent.
The WCJ, as herein relevant, concluded that: 1) Employer failed to meet the burden of proof required to demonstrate that all disability on the part of Claimant had ceased and terminated (WCJ’s Conclusions of Law, Nos. 2 and 5); 2) Employer failed to demonstrate that the original agreement of December 17, 1991, should be set aside (WCJ’s Conclusions of Law, Nos. 3 and 6); and 3) Claimant proved that her medical treatment was causally related to her work injury (WCJ’s Conclusions of Law, Nos. 4 and 7). (R.R., pp. 356-357). Although Employer asserted on appeal that the WCJ erred with regard to all of the aforesaid conclusions2, the Board, in affirming the decision of the WCJ, merely concluded “that there is substantial competent evidence to support the WCJ’s holding that Defendant failed to prove that Claimant’s disability was not caused by the November 1, 1991 injury.” (R.R., p. 386). In so doing, the Board noted that the WCJ, as was his prerogative, rejected the testimony of Employer’s medical witness, Dr. Louis J. lorio (Dr. lorio), as not credible. (R.R., pp. 385-386).3
In its petition for review to this Court, Employer argues that the Board, in affirming the denial of its petition to terminate benefits, erred by concluding that there was substantial competent evidence to support the WCJ’s finding that Employer failed to prove that Claimant’s disability was not caused by the November 1, 1991 injury. Employer also argued that the Board further erred by failing to address its petition to review the agreement for compensation and Claimant’s petition to review medical treatment. (R.R., pp. 391-392). The underlying basis of Employer’s arguments is that it had incorrectly entered into the agreement for compensation based on its mistaken belief that Claimant had suffered a work-related injury in the nature of a herniated disk at L4-L5 when in actuality Claimant’s low back pain was the result of a pre-existing condition which was neither caused nor aggravated by a work-related injury.4
It is important to note that Employer has a separate burden of proof with respect to each of its two petitions. Employer does not contend that Claimant was not disabled as the result of low back pain or that she is now fully recovered and able to work. Rather, Employer argues that Claimant’s disability is not due to any work-related injury or aggravation of a pre-existing condition. Thus, in *1271regard to its termination petition, Employer is required to demonstrate that Claimant’s disability is not causally connected to a work-related injury. See Beissel v. Workmen’s Compensation Appeal Board (John Wanamaker, Inc.), 502 Pa. 178, 465 A.2d 969 (1983).5 The WCJ had concluded that Employer was “required to demonstrate that all disability on the part of the claimant had ceased and terminated.” (Emphasis added) (WCJ’s Conclusions of Law, Nos. 2 and 5).
With regard to its petition to review the agreement for compensation, Employer is required to demonstrate that the agreement contained a true mistake of fact which renders said agreement materially incorrect. See Section 413(a) of the Workers’ Compensation Act (Act)6; Birmingham Fire Insurance Co. v. Workmen’s Compensation Appeal Board (Kennedy), 657 A.2d 96 (Pa.Cmwlth.1995).7 Employer contends that the agreement for compensation contains a true mistake of fact which renders said agreement materially incorrect in that Claimant did not suffer the alleged work-injury, a herniated disk at L4-L5, as was set forth in the nature of injury portion of the agreement.
The majority does not address whether or not Employer satisfied either of its two burdens of proof. Instead, beginning on page five of its opinion, the majority chooses only to address whether or not Claimant satisfied her burden of proof, namely demonstrating that the surgical correction of her pre-exist-ing scoliosis was causally connected to a work-related injury. The majority notes, as a preliminary matter, that the record supports the WCJ’s finding that Claimant sustained a work-related injury to her low back. The majority, however, fails to identify the specific record evidence which supports such a finding. The majority then concludes that:
some work injury, if not a herniated disc, caused Claimant to need low back surgery on August 18,1992.
It does not matter that the surgical team discovered during surgery that the pre-surgery diagnosis was wrong, and that Claimant’s work injury was not a herniated disc, but rather, some other low back problem which required a different surgical procedure. The point is that some work-related injury precipitated the surgery. Thus, because there is a causal connection between the surgery and the work injury, Employer must bear the cost. (Emphasis in original).
I disagree with the majority’s conclusion that Claimant’s surgery was precipitated by a work-related injury. The majority incorrectly concludes that Employer, by initially accepting liability for Claimant’s low back pain which was believed to be the result of a herniated disc at L4-L5, admitted, beyond contest, that Claimant became disabled as the result of a work-related injury to her low back. In so doing, the majority implicitly dismisses Employer’s argument to the contrary thereby summarily denying both of Employer’s petitions.
I believe that Employer, through the testimony of Dr. lorio, satisfied its burdens of proof with regard to both of its petitions. Thus, being of the opinion that Claimant never sustained a work-related injury in the first place, I believe the majority errs in concluding that Claimant satisfied her burden of demonstrating the requisite causal connection to render her August 18, 1992 surgery compensable. Accordingly, since I believe that the majority erred in affirming the decision of the Board in all other re*1272spects, I would reverse and vacate the decision of the Board inasmuch as it denies both of Employer’s petitions and grants the petition of Claimant.
. The petition to terminate benefits was filed on February 3, 1993. The later petition, which sought to review the agreement for compensation of December 17, 1991 and the supplemental agreement of December 24, 1991, was filed on February 2, 1994. (R.R., pp. 2 and 6).
. Employer also asserted that the WCJ erred with regard to Conclusions of Law Nos. 8 and 11. Employer further asserted that Findings of Fact Nos. 8, 17a, and 18(a-f) were not supported by substantial evidence. (R.R. 363-369).
. Dr. lorio testified that, in spite of his previous diagnosis to the contrary, his current medical opinion is that Claimant never suffered from a herniated disc at L5-S1 and that the sole cause of her low back' pain was her scoliosis. (R.R., pp. 115-117, 121-122, 124-125).
. There is no dispute that Claimant had scoliosis, a curvature of the spine, which preceded her earliest allegations of low back pain beginning in June of 1991.
. The burden never shifts to a claimant in a termination proceeding to prove the existence of a causal connection between the disability and the injury. See School District of Philadelphia v. Workmen’s Compensation Appeal Board (Coe), 163 Pa.Cmwlth. 89, 639 A.2d 1306 (1994).
. Act of June 2, 1915, P.L. 736, as amended, 77 P.S. § 771.
. For a mistake of fact or law to justify setting aside a compensation agreement, it must have existed when the agreement was executed. Fehr v. Y.M.C.A., Pottsville, 201 Pa. Superior Ct. 107, 192 A.2d 143 (1963). An employer will not be entitled to seek relief under Section 413(a) of the Act, where employer failed to avail itself of the opportunity to investigate the claim before entering into the agreement. See Cedar Farms, Inc. v. Workmen’s Compensation Appeal Board (Santiago), 665 A.2d 1326 (Pa.Cmwlth.1995); Geriatric & Medical Centers v. Workmen’s Compensation Appeal Board (Facey), 167 Pa.Cmwlth. 590, 648 A.2d 1289 (1994), petition for allowance of appeal denied 541 Pa. 644, 663 A.2d 695 (1995).