"Disability" under the Workers' Compensation Act refers to "incapacity because of injury to earn the wages which the employee was receiving at the time of injury in the same or any other employment." N.C. Gen. Stat. 97-2(9)(1999). An injured employee has the initial burden of proving the extent and degree of his disability. Snead v. Pre-Cast Concrete, Inc., 129 N.C. App. 331, 499 S.E.2d 470, cert. denied, 348 N.C. 501, 510 S.E.2d 656 (1998). To do so, he must demonstrate that he is unable to earn pre-injury wages in the same employment or in any other employment and that the inability to earn such wages is due to his work-related injury. Hilliard v. Apex Cabinet Co., 305 N.C. 593, 595, 290 S.E.2d 682, 683 (1982). the employee may make this showing in one of the following ways: (1) the production of medical evidence that he is physically or mentally, as a consequence of the work related injury, incapable of work in any employment; (2) the production of evidence that he is capable of some work, but that he has, after a reasonable effort on his part, been unsuccessful in his effort to obtain employment; (3) the production of evidence that he is capable of some work but that it would be futile because of preexisting conditions, i.e., age, inexperience, lack of education, to seek other employment; or (4) the production of evidence that he has obtained other employment at a wage less than that earned prior to the injury. (Citations omitted.) Russell v. Lowes Production Distribution, 108 N.C. App. 762, 765, 425 S.E.2d 454, 457 (1993). Only after the employee has met his initial burden of proof does the burden then shift to the employer to rebut the evidence of disability. Coppley v. PPG Indus., Inc., 133 N.C. App. 631, 635, 516 S.E.2d 184, 187 (1999). Furthermore, to permit meaningful appellate review of the Commission's decision, the findings of fact must adequately reflect that plaintiff produced sufficient evidence to meet his burden of proving disability. Id. at 635, 516 S.E.2d at 187. "The Industrial Commission must make specific findings of fact as to each material fact upon which the rights of the parties in a case involving a claim for compensation depend. If the findings of fact of the Commission are insufficient to enable the court to determine the rights of the parties upon the matters in controversy, the cause must be remanded to the Commission for proper findings of fact." Id. (quoting Hansel v. Sherman Textiles, 304 N.C. 44, 59, 283 S.E.2d 101, 109-10 (1981)).