The employer and insurer appeal from the compensation judge’s determination that the employee sustained a Gillette^[1] injury to his low back as of December 21, 2009.  We affirm.

Mark Wittstock was born in 1962.  In 1980, when he was 18 years old, he began working as a commercial roofer.  He worked in this occupation until his claimed Gillette injury in 2009, when he was 47 years old.

As a commercial roofer, Mr. Wittstock worked on flat roofs and primarily replaced old roofs with new roofs.  The physical activity involved in that work did not significantly change over the years.

The first step in the roofing process was to remove the old roof.  The employee would use an axe to chop through the old roofing and insulation.  The old roofing would be cut into two-foot squares weighing about 25 pounds and then shoveled into a wheelbarrow.  The wheelbarrow, when full, would be pushed to the edge of the roof and dumped either into a dumpster from the roof or into a chute leading to a dumpster.  The employee testified that around 1990, roofing companies started using a machine that would cut through the old roof so that an axe was no longer needed and sometime after that the wheelbarrow was replaced with a motorized cart.  The shoveling and lifting of the squares remained the same, however.

After the old roof was removed, 4 x 8 sheets of insulation would be placed and then covered with roofing felt.  The felt came in rolls weighing 50 to 55 pounds.  If the employee was working for a larger company, roofing material would be delivered to the roof by a crane.  Otherwise, the material was hauled up by a worker using a pulley and ropes.  A roofer then carried the material to the spot where it was needed.

After the roofing felt was installed, hot asphalt would then be applied to the roof by mopping.  A mop tub holds the hot asphalt and a roofer would place a mop in the tub to put asphalt on it.  The mop resembled a kitchen mop, but had a pump to add more asphalt.  It weighed about 30 pounds when full.  The worker would then swab the mop back and forth placing the asphalt on the roof and generally covering a 10 foot by 3 foot area in each application.  The employee testified he was taught to do this job by twisting back and forth and not moving his feet.  Mopping would take about three or four hours of a work day.  Finally, gravel would be applied to the roof, initially with a hopper, and then by hand using a pail to reach the areas the hopper could not go.

Between 1980 and 1991, the employee worked for a variety of roofing companies.  He began working for the employer, McPhillips Brothers Roofing Company in 1991.  At the time he started there, he had never had any problems with his low back.

In 1998, the employee was promoted to foreman.  A foreman was responsible for supervision of the roofing crew, but was still required to do roofing work.  The employee testified that about 90 percent of his time as a foreman was spent doing roofing work.  As a foreman, however, the employee was able to choose the work he would do.

The employee sustained an admitted work injury to his low back on May 16, 1997.  He was treated at a chiropractic office and he also received physical therapy.  He was off work four weeks and paid temporary total disability benefits by the employer and its insurer, and was then released to return to his regular duty.  His chiropractor found him to be at maximum medical improvement with no permanent partial disability as of July 7, 1997.  The employee testified he had intermittent low back pain after this time, but missed no time from work because of his low back.

Mr. Wittstock was advised at the beginning of the 2009 season that, because of lack of work, he would no longer be a foreman, but would work only as a roofer.  The last day he worked in that season was December 21, 2009.  The employee was laid off on that date because of lack of work.  The employee testified that on his last day of work he had been doing gravel work with a pail and that his back was bothering him from the work he had been doing.

About January 30, 2010, while he was still laid off from work, Mr. Wittstock decided he was out of condition and needed to do some sit-ups.  As he was doing sit-ups at home, he had sharp pain in his low back that he described as being in the middle of his back and at his beltline.

The back pain did not go away, and the employee saw a chiropractor, Dr. Dwayne Arvold, on February 2, 2010.  Dr. Arvold noted a history of low back pain for the past “1½ weeks” with pain into the right leg and the thigh.  According to the employee, when Dr. Arvold expressed some doubts about being able to help him, the employee decided to see an orthopedist his nephew had seen, Dr. Thomas Rieser at Midwest Spine Institute.

The employee’s first visit with Dr. Rieser was on February 9, 2010.  The history noted “intermittent lower body pains through the 1990s” and a “current episode of lower body pain arose approximately 1½ weeks ago.”  The employee had low back pain with radiation to the right leg.  Dr. Rieser ordered an MRI scan to help in considering the nature of the employee’s complaints.

The MRI scan was done on February 22, 2010, and was read as showing multi-level degenerative changes with the changes most pronounced at L5-S1 with right lateral recess stenosis.  Dr. Rieser referred the employee to physical therapy and ordered a series of epidural steroid injections which were done in March.  The injections did not provide any significant relief, and Dr. Rieser prescribed Neurontin and recommended weight loss.

Discography was done on October 5, 2010, at Dr. Rieser’s advice. Dr. Rieser interpreted the discogram as showing “L4-5 had a significant annular tear reproducing a great deal of the burning and symptoms in his left leg.  L5-S1 reproduces back pain.”  After discussion, surgery was scheduled.

Anterior discectomy and fusion of L4-5 and L5-S1 was performed by Dr. Rieser on November 16, 2010.  On November 18, posterior fusion with internal fixation was done.  The employee did well after surgery, and returned to work with the employer in May 2011.  The employee was able to obtain a position as a “patch” foreman, supervising workers who repaired roof leaks.  He testified he was physically able to handle this job.

The employee filed a claim petition in September 2010, alleging his low back condition was the result of a Gillette injury from his employment with the employer.

On January 11, 2011, the employee was evaluated by Dr. Randall Norgaard on behalf of the employer and insurer.  In his report, Dr. Norgaard stated that the employee’s “history as provided to me, the deposition summary dated November 29, 2010, and the medical records are not consistent with a Gillette injury to the lumbar spine.”  His opinion was that “Mr. Wittstock’s lumbar condition is most consistent with multilevel lumbar degenerative disc disease.”  Dr. Norgaard concluded that, although not related to his employment, the employee’s medical care was reasonable and necessary, and the employee had been temporarily totally disabled since January 2010.

At the request of the employee’s attorney, Dr. Rieser prepared a report on January 6, 2012.  In it, Dr. Rieser stated, “[I]t is my opinion, beyond a reasonable degree of medical certainty, that the roofing work Mr. Wittstock has performed over the past 30 years, culminating in January 2010, was a significant contributing factor in the patient’s development of increasing pain due to increased susceptibility to risk of injury as occurred at the end of January 2010 in the process of doing sit-ups at home.”  Dr. Rieser believed some of the responsibility for the employee’s condition should be apportioned to the 1997 work injury.

In response, Dr. Norgaard wrote a supplemental report in which he disputed the idea that the 1997 injury contributed to the employee’s lumbar condition and stated, “[I]n my opinion, 100 percent of Mr. Wittstock’s lumbar treatment has been related to his preexisting lumbar degenerative disc disease and degenerative joint disease.”  Dr. Norgaard also provided deposition testimony for the hearing.

The employee’s claims were heard by Compensation Judge Bradley Behr on May 3, 2012.  The parties stipulated that the employee was temporarily totally disabled from April 27, 2010, through May 24, 2011, as the result of his low back condition, and that the medical care for the low back had been reasonable and necessary.  The primary issue for the compensation judge’s determination was whether the employee had sustained a Gillette injury to his low back.  In his decision issued June 26, 2010, the compensation judge found a Gillette injury that culminated on December 21, 2009, and awarded benefits.  The compensation judge also apportioned 30 percent of the responsibility for the employee’s low back condition to the 1997 injury and determined the employee had 20 percent permanent partial disability.  The employer and insurer have appealed the determination that the employee sustained a Gillette injury and the determination of apportionment.

The compensation judge determined that the employee sustained a Gillette injury to his low back that culminated on December 21, 2009, the last day the employee worked for the employer before an economic layoff.  The employer contends that the compensation judge erred as a matter of law in making this determination.  The employer argues there can be no finding of a Gillette injury where there was no “breakdown” and the employee was able to do his work without restrictions on the last day of his employment.

To establish a Gillette injury, the employee must prove a causal connection between ordinary work and disability.  Steffen v. Target Stores, 517 N.W.2d 579, 50 W.C.D. 464 (Minn. 1994).  Identification of an appropriate date for a Gillette injury was discussed in Carlson v. Flour City Brush Co., 305 N.W.2d 347, 350, 33 W.C.D. 594, 598 (Minn. 1981).  The court considered liability for a Gillette injury when the employer had changed insurers a month before the employee had to stop working because of her symptoms.  The court refused to apply equitable apportionment between the insurers, holding that “the only rule capable of practical application” was a rule that the injury occurred when the employee was disabled from work.  The court referred to similar decisions in occupational disease cases which had used the phrase “ultimate breakdown.”  The Supreme Court revisited this discussion in Schnurrer v. Hoerner-Waldorf, 345 N.W.2d 230, 233, 36 W.C.D. 504, 508 (Minn. 1984).  The court rejected a rigid rule that the date of injury was always the date of disability from employment, noting that there were “several ascertainable events” in the present case.  The court concluded that “the time by which he had sustained those injuries should be determined on all the evidence bearing on the issue.”

The employer argues that an economic layoff from work is not an ascertainable event because there is no evidence of disability at the time of the layoff.  We considered that argument in a case with similar facts in Yates v. Muller Logging, Inc., No. WC06-210 (W.C.C.A. Jan. 3, 2007).  We noted, “the layoff date was obviously the last day during which the employee’s work activities could have contributed to his disability.”  We also stated, “given that the record reasonably establishes that work-related microtrauma contributed to the employee’s cervical condition, the fact that the employee did not seek medical treatment for two months beyond his layoff cannot be used to justify relieving the employer and insurer of liability for that condition.”

We agree with the compensation judge’s statement in his memorandum “that using the last date of work is most consistent with the accepted definition of a Gillette injury.”  If every day of employment contributes to a Gillette injury, it is not inconsistent with case law to conclude that the date of injury may be the date when the employee stops the employment, whether because of disability or layoff.  The compensation judge did not err in using the employee’s last day of work, December 21, 2009, as the date of the Gillette injury in this case.

The employer also raises the question of whether substantial evidence supports the conclusion that the employee’s low back condition was the result of a Gillette injury.  In its brief, the employer states, “the employee’s low back condition relates to a specific nonwork related incident on January 30, 2010,” referring to the sit-ups which were done by the employee on that date.

Determination of whether there has been a Gillette injury is primarily dependent on medical evidence.  Marose v. Maislin Transport, 413 N.W.2d 507, 40 W.C.D. 175 (Minn. 1987).  There is no medical opinion that the January 30, 2010, activity was in any way a causative factor in the employee’s disability and need for medical treatment.  The compensation judge was presented here with two conflicting medical opinions, both of which had adequate foundation.  He adopted the opinion of Dr. Rieser as the opinion which was most consistent with the documentary evidence and the employee’s testimony.  The choice of medical opinion is one for the compensation judge to make, and the decision by a compensation judge based on a medical opinion with adequate foundation will generally be affirmed by this court.  Smith v. Quebecor Printing Co. 63 W.C.D. 566 (W.C.C.A. 2003). We do so here.

Finally, the employer argues that substantial evidence does not support the compensation judge’s conclusion that 30 percent of the employee’s ongoing low back condition should be apportioned to the 1997 work injury.  The employer argues this opinion is contrary to evidence that the employee had been released to work after the 1997 injury with no restrictions, and was able to do roofing work without lost time.  Dr. Rieser, however, stated apportionment was reasonable, even with that information, because “he did have some ongoing intermittent pain over the decade that he did not seem to have prior to the 1997 injury.  He did not require treatment for it, but it was present nonetheless.”  Substantial evidence, in the form of Dr. Rieser’s opinion supports the compensation judge’s determination on this issue.

The decision of the compensation judge is affirmed.