CAREY, Justice:
In this workmen’s compensation case, the claimant, James E. Peters, has appealed from an order of the Superior Court in favor of Chrysler Corporation, employer, affirming a decision of the Industrial Accident Board. The question presented is whether the claimant is entitled to compensation under 19 Del.C. § 2326(g), which reads as follows:
“(g) The Board shall award proper and equitable compensation for the loss of any member or part of the body or loss of use of any member or part of the body up to 300 weeks which shall be paid at the rate of *662/3* per centum of his weekly wages, but no compensation shall be awarded when such loss was caused by the loss of or the loss of use of a member of the body for which compensation payments are already provided by the terms of this section.”
The claimant injured his back in September, 1958. § 2326(g), quoted above, became effective in May, 1959. In January, 1959, an orthopedist determined that the claimant had a partial disability of 15%. In January, 1963, his back was giving him more trouble and his partial disability increased to 30%. At that time, the orthopedist surgically attempted a fusion of the back. The operation was unsuccessful, however and a second fusion was done in October, 1964. It was successful to the extent that it reduced claimant’s disability to the original 15%. Thereafter, his back gave him periodic difficulty, but in 1968, the doctors determined that further surgical intervention was not warranted.
During the course of the 1963 operation, the orthopedist discovered a previously-undiagnosed congenital deformity in claimant’s back. At the hearing, he stated that the 15% disability was the result of aggravation of the congenital deformity. He also testified that this disability was permanent, and that the permanency existed as early as January, 1959.
It is the claimant’s contention that his injury was not a permanent “loss of use” within the meaning of the statute until 1968, when the doctors concluded that no further surgery should be attempted. He claims that compensation should be awarded for permanent partial disability as determined by the statute in effect on that date.
The employer contends that there was a permanent loss of use as early as January, 1959; that § 2326(g) contains nothing to indicate a legislative intent that it shall be retroactively applied; and that to apply it in this case would constitute a retroactive application.
In denying claimant’s claim, the Industrial Accident Board specifically re