position at Providence Hospital, Anderson injured her lower back and legs. She was treated conservatively by Dr. James Bethea, the carrier-approved orthopedic surgeon, for four years. Anderson left Providence Hospital and took a similar position with BMC in December of 1989. During this time period, Anderson received counseling and began taking anti-depressants. After four years of continued back pain, Anderson eventually sought *491 treatment from Dr. Gal Margalit, who referred her to Dr. John Williams, a neurosurgeon in Augusta, Georgia. In July of 1992, Dr. Williams performed surgery on Anderson for a herniated disk.
In 1993, Anderson was involved in a serious, non-work-related automobile accident in which she injured her neck, head, and teeth, and aggravated prior back, shoulder, and knee injuries. Dr. Margalit referred Anderson to Dr. RobertPeele, who performed surgery on June 10, 1995 on Anderson's left knee related to the automobile accident. Anderson also began seeing Dr. Sale Estefano, a psychiatrist, after her automobile accident. Dr. Estefano diagnosed Anderson with post-traumatic stress disorder with severe depression, panic disorder without agoraphobia, and adjustment reaction with depressed mood.
After a hearing on June 15, 1995, Anderson was awarded workers' compensation benefits for the 1988 accident at Providence Hospital with a 42% impairment to her back. At the time of this hearing, she was out of work due to the recent knee surgery related to her automobile accident. However, immediately prior to the surgery, she had been working approximately thirty hours per week. Her claim for psychological injuries was not addressed by the hearing commissioner, and an