The employee appeals from the compensation judge’s finding that the employee’s admitted work injury was temporary in nature and was not a substantial contributing cause of his need for medical treatment after February 12, 2004. We affirm.

In 2002, Rafael Duran began working for the employer, Railworks, which was engaged in laying light rail tracks. The employee’s work involved lifting rails and equipment, pulling rails into alignment, welding and grinding rail joints, and shoveling and spreading rocks to set the rails.  Much of the work was done in a stooped or bent posture or working on his knees.  The employee sustained an admitted low back injury on May 20, 2003, when he twisted his back while setting down a heavy piece of equipment he had been carrying and he experienced an immediate onset of pain from the low back down through the buttocks and into his lower legs.  The pain was accompanied with a feeling of loss of strength in his legs.

The employee reported the injury to his foreman the same day and was taken by his supervisor to Minnesota Occupational Health for medical treatment.  He was seen there by Dr. Michael Broderdorf.  The doctor noted tenderness over the SI joint and right lumbar triangle with positive straight leg raising on the right at about 40 degrees.    He diagnosed lumbar strain with right leg radiculopathy.  The employee was referred to physical therapy and placed on light duty restrictions with limited lifting, pushing, pulling, and carrying, and no repetitive bending, kneeling or squatting.  He was advised to return in two weeks.

The employee was seen several times at Minnesota Occupational Health during June 2003.  He continued to have back pain and his lumbar range of motion was slightly limited.  Straight leg raising was negative on the left and equivocal on the right.  Physical therapy and restrictions were continued and the employee was started on a Medrol dose pack.  The diagnosis continued to be one of lumbar strain with radiculopathy.  An MRI scan was recommended to assess the employee’s condition.

A lumbar MRI was performed on July 2, 2003.  It showed mild L5-S1 disc dehydration with a small dorsal disc protrusion but without nerve root compression.

When the employee returned to Minnesota Occupational Health on July 9, 2003, he reported that his back was more or less the same.  His physician, Dr. Anderson, recommended that he see Dr. John Dowdle, a back specialist, in light of the prolonged course of treatment for lumbar strain.

The employee returned to Dr. Anderson on July 25, 2003, reporting that he had been in too much pain all week to go in to work.  He still exhibited diminished range of motion and equivocal findings on straight leg raising.  The doctor prescribed Celebrex and further physical therapy with a trial of mechanical traction.  He adjusted the employee’s restrictions to limit lifting at the shoulder and overhead to 20 pounds, with a 30-pound lifting limitation at waist level.

As of the end of the employee’s physical therapy on August 1, 2003, he reported no significant long lasting relief following traction.

Dr. Dowdle saw the employee on August 6, 2003.  The employee noted back and bilateral leg pain and rated his pain at a nine of ten level, higher with activity.  The employee had some tenderness in his low back and pain with flexion and extension, but rotation and side bending were full and his reflex, motor, and sensory exams were normal.  Straight leg raising was negative.  Dr. Dowdle recommended that the employee try an epidural injection at L5-S1, and that he participate in an active exercise program at Physician’s Neck and Back Clinic.  He placed the employee on light duty restrictions with a 20-pound lifting limit. Dr. Dowdle’s impression was of “Mechanical low back pain, mild degenerative disk changes at L5-S1.”

The employee underwent an epidural steroid injection on September 9, 2003. However, when he returned to see Dr. Dowdle on September 23, he reported that the injection had not helped his symptoms.  Dr. Dowdle noted that the employee’s exam was normal and his range of motion was good, but that he complained of back pain and was hesitant with movement.  He continued the employee on light duty restrictions but anticipated that the employee might be able to return to work in his regular job without restrictions after another month.

The employee began the exercise program at the Physician’s Neck and Back Clinic on October 13, 2003, where he was seen by Dr. Charles E. Kelly.  The employee reported that his symptoms had remained unchanged for three months despite the treatment he had received.  He complained of low back pain, constant left buttock pain, and intermittent radiating symptoms into the left and right legs.   Dr. Kelly’s assessment was mechanical low back pain and deconditioning syndrome.  He recommended a short-term active rehabiliation program with an estimated duration of 9 to 12 weeks.

The employee was reevaluated by Dr. Dowdle on November 11, 2003.  Dr. Dowdle noted that the employee had only minor degenerative changes in the lumbar spine and no focal neurological deficits.  Straight leg raising and gait were normal and lumbar range of motion was good.  Dr. Dowdle expressed the view that the employee needed to be active in his exercise program and stated that he was not making adequate attempts to resolve his back complaints.  The employee’s restrictions were continued at their previous levels and he was advised to return in one month.

On December 11, 2003, the employee returned to Dr. Dowdle.  He was still having mechanical back pain.  The doctor recommended continuation of the neck and back program and work restrictions, to be further reviewed on completion of the neck and back program.

The employee was discharged from the program at the Physician’s Neck and Back Clinic on February 12, 2004, after completing 24 sessions.  Dr. Kelly noted that the employee’s subjective back pain and leg complaints remained about the same, although there had been slight objective progress.  His strength was about the same and range of motion was largely unchanged.  In Dr. Kelly’s opinion, the employee had shown a poor response to rehabilitation and had demonstrated significant symptom exaggeration.  He diagnosed regional low back pain and opined that the employee’s leg symptoms were referred and not radicular pain.  He recommended discontinuation of formal rehabilitation and a transition to a home exercise program.  In his view, there was no further treatment option that could help him.  He advised that the employee gradually return to work without restrictions.

Dr. Dowdle saw the employee in follow up on February 17, 2004.  He recommended that the employee observe a 50-pound lifting restriction and avoid repetitive bending and single position activity.

The employee was seen by Dr. Jeffrey Nipper, an orthopedic surgeon, for an examination on behalf of the employer and insurer on March 29, 2004.  The employee reported that he still had low back pain but not as frequent as before.  He described a vague sensation of radiation into extremities, but Dr. Nipper saw no correlation to any radicular pattern.  Dr. Nipper believed the employee’s leg pain was at most referred pain, and not neurologic in origin.  He noted that the employee demonstrated dramatic pain behavior such as facial grimacing and seemingly making a great effort to perform simple tasks, but in an inconsistent manner.  His neurological examination showed no focal deficits.  The employee had a normal gait, and could heel and toe walk, balance on one leg, and squat and rise without difficulty.  Straight leg raising was negative bilaterally.  The employee’s lumbar range of motion was essentially normal.

Dr. Nipper opined that the employee was severely deconditioned and might have had a low back or lumbar strain at the time of the work injury, but that there was no convincing objective evidence of any continuing musculoskeletal pathology.  In his view, the employee had reached maximum medical improvement by early 2004 after the neck and back program, and had no permanent partial disability.  He concluded that the employee’s minor degenerative disc disease and bulging at L5 and S1 was essentially irrelevant.  In his opinion, the employee’s work injury was not a substantial contributing factor to his current complaints, which were due to his pre-existing L5-S1 degenerative disc disease and deconditioning.  He further concluded that the employee’s treatment had been reasonable and necessary up to the completion of the Physicians Neck and Back program, but no further treatment was appropriate for the work injury.  Dr. Nipper stated the employee reached MMI by early 2004 after he completed the neck and back program.  Dr. Nipper considered no work restrictions to be needed.

On May 13, 2004, Dr. Dowdle wrote a letter to the insurer.  He noted having reviewed the opinions of Dr. Nipper and Dr. Kelly.  Dr. Dowdle agreed that the employee’s degenerative changes at L5-S1 were mild and of long-standing chronic duration.  He further agreed that he would have no hesitation in returning the employee to his regular job.  He explained that the employee’s 50-pound lifting limit had been based on the employee’s continued difficulties and subjective complaints. Dr. Dowdle stated the employee had long-standing restrictions due to his pre-existing condition.  Dr. Dowdle reiterated essentially the same opinion in a report dated June 17, 2004.

The employee returned to see Dr. Dowdle on June 29, 2004.  Dr. Dowdle had not seen him since February.   The employee reported continued mechanical back pain.  Dr. Dowdle now concluded the employee should continue to observe a 50-pound lifting limit, and that if sent back to full unrestricted work he would risk another injury.

The employee was seen for evaluation by Dr. James Sturm on August 13, 2004, at the request of his attorneys.  He reported pain in the L4-5 area of his back, worse when seated, and told the doctor he could not sit or stand comfortably for more than 15 to 20 minutes at a time.  Straight leg raising was normal and there was no spasm or tenderness.  Lumbar range of motion was restricted by subjective complaints of pain.  Dr. Sturm concluded that the employee had sustained a lumbar strain in the work incident, but had reached maximum medical improvement.  He recommended permanent restrictions of avoiding lifting more than 50 pounds, repetitive bending, and working in prolonged single positions.

The employee again consulted Dr. Dowdle on February 23, 2005.  He reported persistent continued mechanical back pain with movement and activity.  Dr. Dowdle noted straight leg raising to be restricted to 80 degrees bilaterally.  He diagnosed mechanical low back pain, with a degenerative disc at L5-S1, and continued the employee’s work restrictions.  He opined that the employee might eventually be a candidate for fusion surgery or an artificial disc.

Dr. Dowdle next saw the employee on September 1, 2005.  The employee reported that he had been unable to work because of his persistent continuing back pain.  He was tender in the low back and extension was limited.  Rotation and side bending were painful at the extremes of movement. Reflex, motor & sensory exams were normal and straight leg raising was negative.  Dr. Dowdle recommended the employee return to the neck and back clinic for an active rehabilitation and exercise program.  He suggested that he might consider a discogram and possible fusion if he was not better after that.  On March 29, 2006, Dr. Dowdle stated in his chart notes that the employee’s restrictions were permanent.

A hearing was held before a compensation judge on March 30, 2006. The primary issues were whether the employee’s work injury was temporary in nature and whether Dr. Dowdle’s medical treatment in 2005 was causally related to the work injury.  Following the hearing, the judge found that the employee’s work injury had resulted in a lumbar strain that had resolved as of February 12, 2004, and that the work injury was not a substantial cause of the employee’s symptoms or treatment after that date.  The employee appeals.

The compensation judge found that the employee had no history of low back problems prior to the 2003 work injury.  She accepted as credible the employee’s testimony that he has, since the 2003 injury, continued to have occasional back and leg pain.  However, she also accepted the opinion of Dr. Nipper, the employer and insurer’s medical expert, that the employee’s work injury was a low back strain which was temporary in nature and which temporarily aggravated the employee’s pre-existing degenerative disc disease.

The employee argues that these findings are contradictory, and that neither the law nor substantial evidence supports the finding of a merely temporary injury.  The employee cites cases and principles indicating that the effects of a work injury are compensable where a latent pre-existing condition is made symptomatic or its disabling effects are accelerated by that injury.  Specifically, the employee asserts that, as the employee was essentially symptom-free preceding the injury, began having symptoms following the work injury, and still has similar symptoms, the current symptoms can only be attributed to the work injury.

We disagree. The employee is correct that a work-related acceleration or manifestation of an otherwise non work condition may, in appropriate cases, be compensable.  However, for any period of disability or treatment to remain compensable, it must remain causally related to the work injury.  Here, the compensation judge found that the employee’s symptoms after February 12, 2004, were no longer causally related, whether in whole or in part, to the work injury, but instead were solely related to the pre-existing non work condition.  The continuity and similarity of symptoms following the work injury is evidence which could support a finding of a continuing causal relationship between the symptoms and the work injury, but it is not evidence which requires such a finding. The compensation judge accepted expert medical opinion which denied an ongoing causal link between the work injury and the employee’s symptoms after February 12, 2004.

As we have repeatedly noted, this court will uphold a factual determination based on a compensation judge’s choice of expert opinion, unless the opinion relied upon was without adequate foundation.  Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985), Smith v. Quebecor Printing, Inc., 63 W.C.D. 566 (W.C.C.A. 2003).  In the present case, the opinion of Dr. Nipper provides substantial support for the compensation judge’s findings.  Further support is provided not only by the medical records as a whole, but also by the opinions of the employee’s treating physician, Dr. Dowdle, who agreed that the employee’s restrictions in 2004 were based solely on subjective complaints and his pre-existing non work condition.  While the employee points out that Dr. Dowdle in 2005 recommended further treatment for the employee’s low back condition, we note that there is nothing in that physician’s records giving an opinion as to whether the work injury continues to be a causative factor in the employee’s symptoms or the treatment rendered or recommended.

We affirm the compensation judge’s decision.