The administrative law judge provided no analysis to explain her determination that employee's preexisting disabling conditions did not amount to hindrances or obstacles to employment or reemployment. The phrase "hindrance or obstacle to employment" is not defined in Chapter 287. As a result, we look to case law for guidance in interpreting its meaning:
If the Second Injury Fund is to fulfill its acknowledged purpose, the proper focus of the inquiry as to the nature of the prior disability is not on the extent to which the condition has caused difficulty in the past; it is on the potential that the condition may combine with a work related injury in the future so as to cause a greater degree of disability than would have resulted in the absence of the condition. That potential is what gives rise to prospective employers' incentive to discriminate. Thus, if the Second Injury Fund is to serve its acknowledged purpose, "previous disability" should be interpreted to mean a previously existing condition that a cautious employer could reasonably perceive as having the potential to combine with a work related injury so as to produce a greater degree of disability than would occur in the absence of such condition. A condition satisfying this standard would, in the absence of a Second Injury Fund, constitute a hindrance or obstacle to employment or reemployment if the employee became unemployed.
Wuebbeling v. West County Drywall, 898 S.W.2d 615, 620 (Mo. App. 1995) (emphasis in original).
The foregoing "potential to combine" standard has been consistently cited by the courts to determine whether a preexisting condition constitutes a hindrance or obstacle to employment. See Knisley v. Charleswood Corp., 211 S.W.3d 629, 637 (Mo. App. 2007); Concepcion v. Lear Corp., 173 S.W.3d 368, 371 (Mo. App. 2005); E.W. v. Kan. City Sch. Dist., 89 S.W.3d 527, 538 (Mo. App. 2002); and Carlson v. Plant Farm, 952 S.W.2d 369, 373 (Mo. App. 1997). When we apply this standard, we conclude that
Employee's preexisting hearing loss, tinnitus, vertigo, hernia, low back, and left shoulder conditions amounted to hindrances or obstacles to employment at the time he sustained the primary injury. This is because we are convinced a cautious employer could reasonably perceive each of these conditions as having the potential to combine with a subsequent work related injury so as to produce a greater degree of disability than would occur in the absence of such condition.