1. The determination of controlling event is a legal conclusion which follows from factual findings that an injury is either a new, separate injury or a consequential injury, a recurrence, or a mere temporary aggravation.
2. The law in effect on the date of the new, separate injury determines the amount and period of an injured employee's compensation.
Heard, considered, and decided by the court en banc.
The opinion of the court was delivered by: Anderson, Russell A., Justice
The issue presented by this case, which we review on certiorari, is whether the Workers' Compensation Court of Appeals erred in reversing the compensation judge's determination as to the controlling event for purposes of establishing the amount and period of an injured employee's compensation. We reverse and remand.
On June 19, 1990, Jacqueline Busch sustained injuries to her low back and coccyx when she slipped and fell while working for Advanced Maintenance, a cleaning service. She sought medical care at the Alexandria Clinic on June 21, 1990 for complaints of pain in her coccyx, lower back and legs. A July 6, 1990 CT scan showed a small right disc herniation at L5-S1. Busch experienced an onset of back pain on December 2, 1990, was hospitalized overnight, and was seen by an orthopedist at St. Cloud Orthopedic Associates on Decemberá18, 1990. In a follow-up visit on May 6, 1991, the orthopedist found Busch had reached maximum medical improvement (MMI).*fn1 He ultimately rated permanent partial disability at nine percent pursuant to Minn. R. 5223.0070, subp. 1 (1990).
In September 1991, Busch began working full time for Jo-Ann Fabrics as a cashier. On February 18, 1992, she was seen at the Alexandria Clinic for pain in her coccyx, radiating upward, after lifting a box. On April 28, 1992, Busch was examined by orthopedic surgeon Dr. Mark Engasser at the request of Advanced Maintenance and its workers' compensation carrier, State Farm Mutual & Casualty Company. The doctor noted that most of Busch's pain was in her coccyx area, diagnosed a ligamentous injury to her sacrococcygeal area as a result of the June 19, 1990 fall, and opined that the disc protrusion did not play any role in her ongoing symptoms. Advanced Maintenance and State Farm admitted liability for the June 19, 1990 injury and paid related medical and wage loss benefits. In 1993, Busch agreed to a settlement that included a permanent partial disability claim for a nine percent impairment. Busch continued to work full time, eight hours per day.
In 1994, Busch began working for Viking Foods as a cashier. On November 27, 1995, Busch had an acute onset of low back pain while at work. She was seen at the Alexandria Clinic on December 7, 1995. Her doctor noted that she had "chronic low back pain with intermittent flares" and pain that radiated into both legs, left greater than right, since the June 19, 1990 injury. Over the next several years, Busch reported persistent low back/coccygial pain at her annual physical examinations.
In 1999, Busch found her low back problem worsening and reduced her work schedule to three or four days, or about 24 hours per week. She had a flare-up of low-back pain at work on July 2, 1999, and a CT scan done in August 1999 showed a small herniation and disc space narrowing at L5-S1. On September 13, 1999, Busch tripped over some groceries at work and fell forward to the floor. Shortly after this incident, she experienced severe back pain and shooting pain in her right arm and leg which forced her to reduce her hours at work.
At her December 1999 annual physical exam, Busch indicated that she had experienced significant back discomfort over the preceeding three weeks. Her doctor noted that her back pain dated to the June 19, 1990 injury. Busch was referred to the Institute for Low Back and Neck Care in January 2000. Following an MRI which showed a herniation at L5-S1, Busch underwent a right L5-S1 microdiscectomy on March 10, 2000. Busch's orthopedic surgeon determined that Busch had reached MMI by October 29, 2001 and rated her permanent partial disability at 14 percent. See Minn. R. 5223.0390, subp. 4D (1999).
Busch filed a series of claim petitions for medical and wage loss benefits, including permanent total disability benefits continuing from March 10, 2000, naming Advanced Maintenance and State Farm, Viking Foods and its workers' compensation insurer, State Fund Mutual, and the Special Compensation Fund as parties. Busch's claims came on for hearing on November 20, 2001, at which time the parties stipulated that Busch had been permanently and totally disabled as of March 10, 2000, as defined by the law in effect on the date of both the June 19, 1990 injury and the September 13, 1999 injury. Relevant evidence at the hearing included the opinions of Drs. Jack Drogt and John Dowdle. Drogt, medical consultant for Advanced Maintenance and State Farm, opined that the 1990 injury was not a substantial contributing factor in Busch's need for surgery and apportioned 100 percent of the responsibility for her permanent total disability and medical care to the September 13, 1999 injury. Dowdle, medical consultant for Viking Foods and State Fund, concluded that the 1990 injury was the substantial contributing cause of Busch's disability and that the 1999 injuries were temporary aggravations of the 1990 injury. He apportioned all responsibility for the low back surgery and ongoing disability to the 1990 injury.
The compensation judge found that Busch's June 19, 1990 and September 13, 1999 injuries were both substantial contributing causes of Busch's permanent total disability and need for medical care and allocated 75 percent of the liability for benefits to the 1990 injury and 25 percent of the liability for benefits to the 1999 injury. The judge further determined that the 1990 injury was the controlling event and awarded medical and permanent total disability benefits based on the allocation of liability, including supplementary benefits for that part of the award allocated to the 1990 injury. On appeal, the Workers' Compensation Court of Appeals (WCCA) reversed the controlling event determination and vacated the award of supplementary benefits. The WCCA, applying Joyce v. Lewis Bolt & Nut Co., 412 N.W.2d 304 (Minn. 1987), reasoned that because the compensation judge found the September 13, 1999 injury "to be a 'new, separate injury' and not a consequential injury or simple ...