The employee appeals from the denial of his claimed benefits following the compensation judge’s determination that the employee’s admitted work injuries of December 23, 2010 and March 27, 2012 were temporary in nature and did not aggravate the employee’s spondylolisthesis.  We affirm.

In 2005, the employee, Rayfield Lee, began working for 3M, the employer herein.  The employee sustained low back injuries on December 23, 2010 and March 27, 2012.  The employer and its insurer admitted liability for temporary injuries to the employee’s low back.

Near the end of his shift on December 23, 2010, the employee experienced a tingling sensation in his low back while pushing a dumpster.  Shortly thereafter, he felt a sharp pain in his low back as he was emptying the dumpster.  The employee first received medical treatment on December 27, 2010, when he reported to the emergency room at North Memorial Hospital.  He reported lifting a dumpster and experiencing increasing pain in his groin and leg.  The employee underwent an x-ray and sonogram.  He also received some pain medication and was instructed to follow up with his doctor.

On January 5, 2011, the employee presented to North Clinic to “establish care.”  He was “following up from a low back strain that happened at work.”  The employee said he was having some difficulty with heavy lifting at work.  The employee thought he needed some work restrictions for a few days.  On examination, the employee had bilateral paraspinous tenderness in the lower back.  He was assessed with a low back strain.  The employee was given restrictions of avoiding heavy lifting for two weeks.  He was then to return to his normal duties.

In his appeal brief, the employee indicates that he did not work between December 23, 2010 and January 5, 2011, although the treatment note from North Clinic on January 5, 2011 indicated that the employee was “back at work, but he is having some difficulty with heavy lifting.”  In addition, the employee admitted on cross-examination that the only time he missed following the December 2010 injury was due to the plant closure for the holidays, and he confirmed that no doctor took him off work during that time.  Regardless, the employee testified that as of January 10, 2011, he had returned to doing his regular duties including overtime, without any restrictions.  The employee testified that after the December 2010 injury, he continued to have ongoing low back pain.  Some days were worse than others, but the employee said he could do his job.

The employee did not treat for his back again until August 10, 2011, when he returned to North Clinic.^[1]  He reported “back pain since Thurs.”  The employee testified that he had returned to North Clinic on August 10, 2011 because his pain had become so bad that he could not work anymore.  The medical record indicated that the employee had missed work, and he believed that he had missed about three or four days at that time.  The employee was given a note allowing him to continue working without restrictions.  The employee testified that he continued to work with back pain after the August 10, 2011 visit.

The employee’s next treatment for his back occurred on November 2, 2011, when he returned to North Clinic.  At that time, he reported having back pain for the last “4 days.”  The employee was given some additional pain medication.  He also began a course of physical therapy.  The employee asked to be returned to work without restrictions.  The employee testified that he thought his back would get better, but it ended up getting worse instead.

The employee was referred to Twin Cities Orthopedics, and he underwent an initial evaluation with Dr. Benjamin Gulli on December 15, 2011.  He was being evaluated for chronic back pain, which “has been present for about three months.”  The report indicated that there was “no specific injury.”

The employee underwent an MRI on December 19, 2011.  The following impressions were given:

The employee then underwent epidural steroid injections and physical therapy.  On January 12, 2012, he told Dr. Gulli that his back pain had improved somewhat after injection, but he still had ongoing back pain.

The employee saw Dr. Paul Crowe at Twin Cities Orthopedics on January 30, 2012.  He reported a chief complaint of back pain for the last year.  The employee reported that he had been injured at work while pushing a dumpster.  He said his pain had been on and off since that time.  Doctor Crowe reported that the MRI showed some neural foraminal narrowing.  X-rays also showed “L5-S1 spondylo that is fixed and grade I to nearly grade II spondylo with no motion.”  The employee did not want surgical intervention.

On February 13, 2012, the employee followed up with Dr. Crowe.  Doctor Crowe discussed treatment options, including a fusion surgery.  Doctor Crowe felt the employee would be a candidate for the fusion, but the employee “does not have any interest in that at this point.”  Eight visits of physical therapy were recommended for core stabilization.

The employee returned to see Dr. Crowe on February 27, 2012.  At that time, the employee was told to return as needed because he was not interested in surgery.  The employee said that he had missed a few days from work and needed a release to return to work.  The employee returned to see Dr. Crowe again on March 12, 2012, but he still had not started physical therapy.  The employee asked Dr. Crowe to fill paperwork out for his employer indicating that his situation “is not work compensation or anything.”

The employee sustained his second work injury on March 27, 2012.  The employee opened a 50- to 60-pound bag of parts to place into a tank.  The bag fell into the tank.  The employee tried to grab the bag, but he tripped over a stepladder and fell against the tank.  He testified that he injured his shoulder and his low back.  After reporting the injury to his supervisor, the employee was sent to the nurse’s office, where he iced his back.  The employee was also seen at Minnesota Occupational Health on March 27, 2012.  He was told to return to work with restrictions.

On March 28, 2012, the employee was involved in a motor vehicle accident.  The employee’s vehicle was struck by a taxi.  The employee saw Dr. Crowe on April 2, 2012, and Dr. Crowe indicated that the employee was rear-ended and that his car was totaled.  However, photographs of the accident were presented at hearing, and the compensation judge found that the photographs “show the employee’s car was side-swiped, not rear-ended, and the car was not totaled.”  In her memorandum of law, the compensation judge noted that although the employer and insurer contended that the motor vehicle accident was the cause of the employee’s need for surgery, the photographs placed into evidence showed that the damage to the employee’s car consisted of scrapes along the passenger side of the vehicle, and “[c]learly the employee was not rear-ended at that time.”

When the employee saw Dr. Crowe on April 2, 2012, he advised Dr. Crowe that he was now ready to proceed with the fusion surgery.  Doctor Crowe performed the fusion surgery in August 2012.  The surgery was performed to address spondylolisthesis.

The employer and insurer sent the employee for an independent medical examination with Dr. Rick Davis.  Doctor Davis also gave a deposition in preparation for hearing.  Doctor Davis opined that the employee’s December 2010 injury was temporary in nature.  He felt that it was a lumbar strain that had resolved before the employee treated again in August 2011.  Doctor Davis noted that the employee had returned to work without restrictions, and he did not need ongoing medical treatment after the resolution of his lumbar strain.  Doctor Davis did not believe that when the employee returned to North Clinic in August 2011, his symptoms were related to spondylolisthesis or consistent with the presentation of an aggravation of spondylolisthesis.

Doctor Crowe also gave a deposition in preparation for the hearing in this matter, and he opined that there was no objective evidence that either of the claimed work injuries resulted in any anatomic changes to the employee’s lumbar spine.  Doctor Crowe said he could not be sure whether the December 2010 incident was a manifestation of an underlying spondylolisthesis condition or an aggravation of that underlying condition, but he was not certain of the difference between the terms “aggravation” and “manifestation.”  He could only say that he knew spondylolisthesis was present before the December 23, 2010 injury.  Doctor Crowe opined that the employee’s symptoms and fusion surgery were related to the employee’s work injuries, and his opinion was based entirely on the history that he obtained from the employee, including his history of ongoing symptoms.  Although there had been no anatomic changes as a result of the work injuries, Dr. Crowe apportioned liability evenly between the two injuries.  He conceded that he was not basing his apportionment opinion on “scientific ability to prove it” but more on his “gut feeling.”  Doctor Crowe agreed that the employee had already been recommended for surgery for his spondylolisthesis by the time of his March 2012 work injury.

The case proceeded to hearing before the compensation judge on March 14, 2013.  The compensation judge was asked to decide whether the employee’s work injuries of December 23, 2010 and March 27, 2012 were substantial contributing factors in the employee’s back condition and subsequent fusion surgery and whether the employee had been temporary totally or temporary partially disabled at various times, as claimed.

The compensation judge heard testimony from the employee.  She also received a number of other exhibits from the parties, including medical records and deposition testimony from Dr. Crowe and Dr. Davis.  The compensation judge described the employee as a “hard-working, highly-motivated worker.”  She noted that the employee accepted all overtime work available to him, and she indicated that he also appeared to be “stoic, not complaining to any degree of physical aches and pains.”  However, the compensation judge concluded, based on the medical evidence and Dr. Davis’s opinions, in particular, that the admitted work injuries were temporary in nature and did not aggravate the employee’s spondylolisthesis.  Therefore, she decided that the work injuries were not substantial contributing factors in the employee’s back condition, and she denied the employee’s claims in their entirety.

The employee first indicates that the “crux” of his appeal is that Dr. Davis’s opinions lacked sufficient foundation.  This court will generally affirm the decision of a compensation judge based on a choice between expert opinions, “so long as the accepted opinion has adequate foundation.”  Smith v. Quebecor Printing, Inc., 63 W.C.D. 566, 573 (W.C.C.A. 2003) (citing Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985)).  Doctor Davis reviewed medical records concerning the employee’s condition and medical treatment.  He took a history from the employee and conducted a physical examination.  As such, Dr. Davis had sufficient information to establish foundation for a medical opinion.  See Drews v. Kohl’s, 55 W.C.D. 33, 38-39 (W.C.C.A. 1996), summarily aff’d (Minn. July 11, 1996) (citing Grunst v. Immanuel-St. Joseph Hosp., 424 N.W.2d 66, 40 W.C.D. 1130 (Minn. 1988)).  The employee’s challenge to the compensation judge’s reliance on Dr. Davis’s opinions goes to the weight of those opinions and not foundational issues.  Drews, 55 W.C.D. at 39-40.^[2]

Ultimately, the employee argues that the “evidence, taken as a whole, does not support the compensation judge’s finding that the Employee’s work injuries did not aggravate his spondylolisthesis.”  This court is required to look at all the evidence in performing its review function, but it must give due weight to the compensation judge’s opportunity to judge the credibility of witnesses and must uphold the findings based on conflicting evidence or evidence from which more than one inference might reasonably be drawn.  Even v. Kraft, Inc., 445 N.W.2d 831, 834, 42 W.C.D. 220, 225 (Minn. 1989) (citing Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 37 W.C.D. 235 (Minn. 1984)).  “Assessment of witness’ credibility is the unique function of the trier of fact.”  Brennan v. Joseph G. Brennan, M.D., P.A., 425 N.W.2d 837, 839-40, 41 W.C.D. 79, 82 (Minn. 1988).  It is not the role of this court to evaluate the credibility and probative value of witness testimony and choose different inferences from the evidence than the compensation judge.  See Krotzer v. Browning-Ferris/Woodlake Sanitation Serv., 459 N.W.2d 509, 512-13, 43 W.C.D. 254, 260-61 (Minn. 1990); Redgate v. Sroga’s Standard Serv., 421 N.W.2d 729, 734, 40 W.C.D. 948, 957 (Minn. 1988).

The compensation judge considered the employee’s testimony with regard to his symptoms, his personality, and his motivation to continue working.  She also carefully considered the medical evidence submitted, including the expert opinions of both Dr. Crowe and Dr. Davis.  The compensation judge noted that the employee was diagnosed with spondylolisthesis in December 2011 and that the fusion surgery was recommended before the occurrence of the March 27, 2012 injury.  As such, the compensation judge determined that the March 2012 injury was not the cause of the fusion surgery, and she focused her causation decision on the time following the December 2010 injury.

The compensation judge discussed both expert opinions in detail.  She noted that both experts testified that spondylolisthesis was a congenital or early developmental condition that might never become symptomatic and that both experts also indicated that spondylolisthesis could become symptomatic following a trauma.  The compensation judge noted Dr. Davis’s testimony indicating that, in his experience, once spondylolisthesis was aggravated, it remained symptomatic thereafter, and the overall majority of patients with symptomatic spondylolisthesis will then miss work and seek treatment.  Doctor Davis did not find it plausible that once the condition was aggravated, an individual would be able to work full-time, along with significant overtime, while maintaining the ability to perform unrestricted work and requiring no medical treatment.  As such, Dr. Davis opined that the employee’s pattern of treatment following the December 2010 injury was more consistent with the occurrence of a stain/sprain and temporary injury than it was with symptomatic spondylolisthesis.

The compensation judge also discussed Dr. Crowe’s testimony and opinions in detail, including his opinion that neither of the work injuries caused or changed the spondylolisthesis condition in any significant way.  The compensation judge also noted that in reaching his causation opinion, Dr. Crowe relied on the history given to him by the employee.

The employee argues that the compensation judge did not make any finding that the employee’s testimony regarding his continuous, ongoing back pain following the December 23, 2010 injury was not credible.  As such, the employee challenges the decision to reject Dr. Crowe’s causation opinion, and he argues that the case should be remanded for a finding on whether the employee testified credibly with relation to his ongoing, continuous back pain following the December 2010 work injury.  We disagree.  The compensation judge decided to choose Dr. Davis’s causation opinions over those of Dr. Crowe based, in large part, on Dr. Crowe’s reliance on the history given to him by the employee.  Thus, the compensation judge’s decision includes, at least, an implicit finding that the employee’s history was not credible.

The employee also argues that Dr. Davis’s opinion could not have supported the compensation judge’s decision because “Dr. Davis was entirely ignorant of Employee’s atypical nature as a patient.”     The employee argues that Dr. Davis improperly compared the employee’s behavior with the behavior of “typical” patients that have spondylolisthesis.  The “foundational problem,” according to the employee, “is that there was no evidence presented at hearing from which a reasonable person could conclude that that employee behaved like a ‘typical’ patient or the ‘overall majority of patients.’”  Instead, the employee argues that the employee was an atypical patient who continued to have back pain after his December 2010 injury but continued working because of his hard-working and “stoic” nature.

The compensation judge was well aware of the employee’s testimony regarding his “atypical nature.”  Although the employee testified that he had ongoing symptoms, the medical records from the year or so after the injury indicate that the employee did not have ongoing symptoms and that he did not relate his symptoms, when he had them, to his work injury.^[3]  The compensation judge weighed the employee’s testimony against the medical evidence and the expert opinions, and she rejected the employee’s position that he had ongoing symptoms related to the work injuries.  The medical evidence cited by the compensation judge, including the well-founded opinions of Dr. Davis, provides substantial evidentiary support for the compensation judge’s determination, and we affirm.