The employee appeals from the compensation judge’s finding that her 2010 low back injury was temporary in nature, that she had not proven by a preponderance of the evidence that she sustained a new injury to her low back on or about February 4, 2012, April 9, 2012, or April 24, 2012, and the compensation judge’s denial of a recommended discogram.  We affirm.

The employee began working for the employer, G & K Services, in about 2007.  Her usual job involved selecting garments hanging on racks, hanging the garments on bars or trolleys attached to an overhead track system, and walking the garments along the system to other locations within the employer’s facility.

On June 21, 2010, the employee and two co-workers were asked to mop up water from a plumbing leak that occurred the night before.  After pushing the water with a squeegee, they were instructed to sop up the water with towels, which they placed into a three-foot-high trash container.  Each time it became full, the container was placed onto a wheeled dolly and rolled to a laundry area where the towels were unloaded.  While the employee was lifting the full container onto the dolly, she felt a severe pain in her lower back and with pain extending down her right leg to her knee.  She reported the injury to a supervisor, who advised her to report it to her regular supervisor.  Her supervisor had left for the day.  The employee continued working and finished her shift.

On the following day, June 22, the employee reported her injury to her supervisor, who helped her call an injury triage line for MedCor, a medical provider under contract with the employer.  The employee’s native language is Spanish, so she was assisted by a translator while talking to the MedCor nurse.  The nurse recorded that the employee’s middle to lower back began bothering her after she had finished mopping up water, and that her pain had been moderate and constant since then.  She reported that the employee did not have severe pain, pain radiating to her leg, or leg numbness.  The nurse recommended that the employee administer self-care by icing the back and to seek further medical treatment as needed.

The employee continued to work without any time lost from work.  She did not seek any further medical treatment until several months later on September 2, 2010, when she was seen by Dr. Huset at Twin Cities Occupational Health.  Dr. Huset diagnosed a lumbar strain and pelvic tilt syndrome.  He recommended anti-inflammatory and pain medications, placed the employee under work restrictions, and advised her to return in one week.  When the employee returned on September 9, she reported worsening symptoms, including pain radiating into her left foot.  Dr. Huset diagnosed a low back strain.  He referred the employee for physical therapy and modified the employee’s medications.

The employee was provided with work within her light-duty restrictions.  She also participated in physical therapy, but reported it was not helpful.  She testified that her symptoms continued to intensify over time.  On October 1, 2010,  the employee underwent a lumbar MRI, which indicated mild degenerative changes, including a mild posterocentral protrusion of the L4-L5 disc, a posterocentral protrusion of the L5-S1 disc abutting the thecal sac and the bilateral SI nerve roots, and mild facet joint arthropathy and ligamentum flavum thickening at the L5- S1 level.

Dr. Huset’s treatment notes on October 7 and 21, and November 4, 2010, indicate that the employee’s low back pain was no longer radiating into either lower extremity.  On November 4, 2010, Dr. Huset referred the employee to an orthopedic surgeon “at the earliest convenient time.”  The employee no longer had work restrictions following her last visit with Dr. Huset on November 4, 2010.

The employee did not consult with an orthopedic surgeon.  She missed no time from work and sought no further treatment for her low back until May 1, 2012.  The employee testified, however, that the pain in her lower back and her right leg continued unabated during this entire 17-month period.  She characterized the pain as so severe that she was not able to perform her normal household activities.

On October 31, 2011, the employee began working in a second shift stock puller position she had bid for.  This job required the employee to remove garments from a spider line and separate them by size and color, putting them onto either Z-bars or trolleys which formed part of an overhead garment conveyor system.  She would then guide the Z-bar or trolley to its appropriate destination in the employer’s facility.  This work involved some twisting, bending, and reaching, but did not involve heavy lifting or heavy pushing or pulling.

The employee saw a physician at United Family Medicine on December 19, 2011 for a skin rash she thought was being caused by handling dusty clothing on her job.  Although the employee testified that her back pain had remained at the level of an eight on a scale of zero to ten since the 2010 injury, she did not mention back pain to this doctor.  The employee testified that she saw no reason to do so as the purpose of the visit was treatment for her rash.

In her hearing testimony, the employee claimed that the bending and twisting in the stock puller job caused her pain.  She said that on several occasions she told the Stock Room supervisor, Nick Kehl, that her new duties caused her pain.  The employee testified that she began to experience left leg pain in 2012.  She also testified that her back pain was at ten on a scale of ten and that she had difficulty with standing up on her own.

Nick Kehl testified that the employee, while working in the stock puller job, had complained of pain symptoms she related to her June 21, 2010 injury, and had denied any new injury when asked her if she wanted him to report one.  He noted that, at times, the employee’s visible level of pain seemed inconsistent.  She might be walking normally, but if he asked how she was feeling, she would “switch real quick.”  The employee, on the other hand, testified that she had asked Mr. Kehl to report an injury, but that he had refused to do so.

As a result of the ongoing pain complaints, on April 24, 2012 the employer arranged another phone consultation for the employee with the MedCor triage line.  The employee spoke with a registered nurse who advised her to see a doctor within 24 hours.

The employee was seen at Twin Cities Occupational Health on May 1, 2012.  She gave a history of continuous pain with radiation into her right leg that had been well controlled with Advil since her last visit with Dr. Huset on November 4, 2010.  She reported that her symptoms had started to worsen on April 9, 2012, such that the Advil no longer helped.  The employee was given work restrictions and was referred to an orthopedic specialist.

On May 24, 2012, the employee saw Dr. Sherman at Twin Cities Orthopedics.  She told Dr. Sherman that prior to her June 21, 2010 work injury, she had experienced occasional mild back pain for which Advil was helpful.  After the work injury, she had experienced right and left leg pain in addition to low back pain.  She had “lived with” her symptoms until they escalated after she changed job duties in November of 2011, becoming particularly pronounced in February 2012.  Dr. Sherman recorded that the employee had a normal gait.  Straight leg raising was negative bilaterally.  The employee reported pain with flexion, extension, and left and right lateral bending, and was tender even to light touch throughout the lumbar spine and into the bilateral sciatic notches.  Dr. Sherman noted what he considered to be significant positive Waddell signs, including superficial and non-anatomic tenderness, positive trunk rotation, give-way weakness throughout both lower extremities, a stocking glove distribution of numbness, and overreaction.  He diagnosed aggravated underlying degenerative changes to the low back.  He referred the employee for aggressive physical therapy and imposed temporary restrictions of no lifting more than 40 pounds and to avoid frequent bending and twisting.  The employee was to return to unrestricted work starting on July 1, 2012.

The same day, May 24, the employee went to the Regions Hospital Emergency Department for an acute flare up of her low back pain.  She stated that she was having a flare up of symptoms from her 2010 work injury, which had gotten worse since February when she started performing more physical duties at work.  The employee stated that she was unable to walk due to pain, and was taken to the triage department in a wheelchair.  The emergency physician noted that the employee had seen another physician earlier that day, but that her family didn’t think that he had helped her.  The employee’s exam was recorded as normal other than for some paraspinal tenderness, with no neurologic difficulties.  She was able to ambulate independently without difficulty.  The emergency room physician recommended physical therapy, prescribed Flexeril, and recommended that the employee follow up with her regular physician.

The employee was provided with a QRC, who visited her job site on July 10, 2012.  He determined that the employee’s job was within her restrictions and that the employee continued to work within her restrictions.  The employee told the QRC that she wanted a second medical opinion.

On July 23, 2012, the employee was seen by Dr. Mark Agre at Impact Physical Medicine.  Dr. Agre noted that the employee had an initial low back injury on June 21, 2010, with multiple subsequent flare-ups.  He referred her for physical therapy, placed her on a four-hour per day work limitation, and recommended a 40-pound lifting limit with only occasional bending, twisting, and turning.

The employee participated in physical therapy from July 23, 2012, through December 14, 2012, but reported little improvement.  Dr. Agre suspected a mechanical back problem, but felt he could not rule out her L5-S1 degenerative discs.  On October 30, 2012, he treated the employee with lumbar sciatic medial branch nerve blocks which provided some partial and temporary improvement.  Dr. Agre referred the employee to Dr. Lutz at Interventional Pain Medicine.  On November 13, 2012, the employee underwent an epidural steroid injection without lasting improvement.

An MRI of the employee’s lumbar spine was performed on December 7, 2012.  It showed mild to moderate facet arthropathy at L5-S1 and a partial annular tear or central annular bulge at L5-S1 without neural impingement.  There was a slight narrowing of the neural foramina at L5-S1.  The exam was otherwise unremarkable.

On December 14, 2012, Dr. Agre noted that the medial branch blocks administered by Dr. Lutz had provided only 40 to 50 percent initial improvement and then exacerbated the employee’s pain.  He reviewed the newest MRI results and noted that it showed less impairment than the prior 2010 imaging.

In January 2013, the employee was taken off work by the employer because no further work within her restrictions was available.  She elected to go on FMLA leave for three months, during which period the employer and insurer paid temporary partial disability benefits.  During this period, the employee saw Dr. Lynn at Summit Orthopedics.  He opined that the employee’s pain was partly discogenic and partly due to advanced L5-S1 facet arthritis.  He recommended discography and suggested that fusion surgery might be appropriate if the discogram results were concordant with the employee’s symptoms.

On March 26, 2013, the employee was seen by Dr. Engasser for an evaluation on behalf of the employer and insurer.  Dr. Engasser diagnosed low back pain, lumbar disc and facet disease at L5-S1 with slight neural foraminal narrowing, but without neural impingement, and nonorganic pain and obesity.  Dr. Engasser’s examination findings included a positive shoulder and head compression test, a positive squat test with right hip pain with minimal squatting, pain on very light palpation of the entire lumbar spine, inconsistencies in movement when moving spontaneously versus during examination, and a nonorganic sensory loss.  Based on his examination, he found the employee’s symptoms of pain disproportionate to her objective examination findings.  In light of the employee’s delay in obtaining initial treatment, the subsequent 17-month gap in treatment, the 2012 MRI findings, and what he considered to be multiple indicators of symptom magnification, Dr. Engasser opined that the employee either had not sustained an injury to her low back in 2010 or, if she did, it was a temporary aggravation of a pre-existing degenerative condition.

On April 2, 2013, Dr. Agre released the employee to full time work with a 20-pound lifting restriction and with only rare bending, twisting, turning, and rotating.  The employee returned to work in a job within these restrictions.  The employee used a scanner and computer to create bar code tapes which she would affix to garments before moving the garments down a conveyor.  The employee told the employer that she could not perform this work due to pain.  The employer terminated her employment and resumed payment of temporary total disability compensation.  In May 2013, the employer and insurer filed a notice of intention to discontinued benefits.

Dr. Lutz prepared a report on September 3, 2013 at the request of the employee’s attorney.  He diagnosed an L5-S1 degenerative disc resulting in central axial pain, facet arthropathy, and leg symptoms which he attributed to a possible positional impingement of the SI nerve roots.  Dr. Lutz opined that employee had first injured her lumbar spine at work in 2010, and that her condition was exacerbated due to repetitive bending, stooping and lifting of garments by early 2012 as a result of her change in work duties.

The employee filed a claim petition and an objection to discontinuance on June 24, 2013.  She filed an amended claim petition on March 11, 2014.

The compensation judge found that the employee had sustained a work injury on June 21, 2010, in the nature of a temporary aggravation to an underlying, pre-existing condition.  The compensation judge further found that this aggravation resolved by November 4, 2010.  The compensation judge found that the preponderance of evidence failed to support a new injury after that time.  The compensation judge accordingly also denied the employee’s request for approval of a discogram on the basis that it was not related to the employee’s work injury.

On appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1 (2014).  Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.”  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of evidence or not reasonably supported by the evidence as a whole.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).

“[A] decision which rests upon the application of a statute or rule to essentially undisputed facts generally involves a question of law which [the Workers’ Compensation Court of Appeals] may consider de novo.”  Krovchuk v. Koch Oil Refinery, 48 W.C.D. 607, 608 (W.C.C.A. 1993).

The employee claimed an initial personal injury to her low back on June 21, 2010, when she was lifting a container filled with water-soaked towels onto a dolly.  She claimed further injury from the nature of the work she later performed as a stock puller, resulting in an alleged aggravation to her low back on February 4, 2012, April 9, 2012, or April 24, 2012.

The compensation judge found that the employee sustained a work injury to her low back on June 21, 2010, in the nature of lumbar sprain/strain which temporarily aggravated the employee’s pre-existing low back condition.  The compensation judge found that the June 21, 2010 work injury resolved and that maximum medical improvement was reached by November 4, 2010, without any associated residual disability or need for work restrictions.  The compensation judge further found that the employee had not proven by a preponderance of the evidence that she sustained any new injury to her low back on or about February 4, 2012, April 9, 2012, or April 24, 2012.

The employee appeals from the finding that the employee’s June 21, 2010 work injury was temporary in nature, and from the findings denying any subsequent work injury to her low back.

A.  The employee’s Wold argument.

The employee argues that the compensation judge erred as a matter of law in reaching the conclusion that her injury of June 2010 was temporary, citing Wold v. Olinger Trucking, Inc., slip op. (W.C.C.A. Aug. 29, 1994).  In Wold, this court identified several factors which the finder of fact might consider when determining whether an aggravation of a pre-existing condition is temporary or permanent.^[1]

The employee acknowledged that this court has held that a compensation judge is not required to address each of these factors in deciding whether a work injury is permanent or a temporary aggravation.  The employee further acknowledged that other facts in a given case may also be significant.  The employee, however, argued that the specific factors “represent the law’s use of inductive reasoning” and that the result in this case should be reversed because, in the employee’s view, the application of these factors would support her claim to a permanent, rather than a temporary injury.

In her brief, the employee sets out her own Wold factor analysis, which she asks this court to adopt.  The employee’s proposed analysis would require the court to substitute different inferences from the evidence and to give different weight to portions of the evidence than did the compensation judge.  To do so would not comport with the scope of our review as an appellate court and would require that we ignore the Hengemuhle standard.^[2]  Substantial evidence supports the compensation judge’s factual determination that the June 2010 injury was temporary and we therefore decline to adopt the employee’s argument.

B.  Expert opinion of Dr. Engasser.

The compensation judge’s findings and accompanying memorandum indicate that she relied on expert medical opinion as well as the timing of the medical treatment as reflected in the medical record.  The compensation judge noted there was agreement among the medical experts that the employee had pre-existing degenerative changes in her lower spine which the compensation judge characterized as “the essential cause” of the employee’s back problems.  On the question of whether the employee’s 2010 work injury was temporary in nature, the compensation judge took particular notice of the absence of any medical treatment for over 17 months, from November 2010 until May 2012.  The compensation judge accepted the opinion of Dr. Engasser, who considered any injury sustained in the June 21, 2010 lifting incident at work was, at most, temporary in nature.

With respect to the claim of a later injury, the compensation judge again relied on the opinion of Dr. Engasser, who examined the employee on March 26, 2012.  The doctor noted that the employee exhibited a number of signs of symptom magnification and reported pain disproportionate with the minimal objective findings on examination.  The compensation judge also noted that Dr. Sherman had made similar findings ten months earlier in May 2012.  The compensation judge also found the testimony of the employee’s night shift supervisor, Nick Kehl, more credible than the employee with respect to whether she had reported a new injury to him while working in the stock puller job.

As the trier of fact, it is the compensation judge’s responsibility to resolve conflicts in expert medical testimony and, where there is adequate foundation for the opinions adopted by the compensation judge, this court will normally uphold the compensation judge’s choice among medical experts.  See Nord v. City of Cook, 360 N.W.2d 337, 342-43, 37 W.C.D. 364, 372-73 (Minn. 1985).

The employee argues, however, that the compensation judge’s reliance on the expert medical opinion of Dr. Engasser was unreasonable on two grounds.  First, she contends that the compensation judge erred in admitting his opinion into evidence over her objection.  At the beginning of the hearing below, the employee objected to the admission of the report of Dr. Engasser on the basis that this physician had not been aware of the deposition testimony of the employee’s supervisor, Mr. Kehl, who admitted that the employee exhibited pain and discomfort at times during her work.  The compensation judge overruled the objection and admitted the report, noting in particular that the deposition testimony of Mr. Kehl had not yet been taken before Dr. Engasser performed his examination and authored his report.  The compensation judge ruled that the fact that Dr. Engasser did not have this information was a matter going to the weight, rather than the admissibility, of the Engasser report.  We agree.

Evidentiary rulings are generally within the sound discretion of the compensation judge.  See Cici v. Methodist Hosp., 63 W.C.D. 421, 426 (W.C.C.A. 2003).  On review, considerable latitude is given to a compensation judge with respect to the conduct of a workers’ compensation hearing under Minn. Stat. § 176.411, subd. 1., which states:

Further, we note that the absence of this information does not significantly affect the foundation for Dr. Engasser’s opinion.  Dr. Engasser specifically noted that the employee complained of a significant level of pain both at work and in her everyday activities.  He noted that she came to his office using a cane, and exhibited other signs of discomfort.  His opinion was based in significant part on his observation that the employee exhibited symptoms of pain which were disproportionate to the objective findings on examination.  Thus, it seems unlikely that Dr. Engasser’s opinion would have been affected by the knowledge that Mr. Kehl had seen the employee show signs of pain while at work, or that she had complained to him of pain.  In any event, the compensation judge was entitled to consider the absence of this information in determining what weight to give to this expert opinion evidence.  Accordingly, we conclude that the compensation judge did not err in admitting Dr. Engasser’s opinion into evidence.

The employee next argues that Dr. Engasser’s opinion was defective as a matter of law.  She points out that the doctor formulated his opinion, in part, on having observed so-called Waddell signs^[3].  The employee made this argument to the compensation judge and offered several medical journal articles disputing the validity of Waddell signs as indicators of malingering.  As further support for her position, the employee refers us to a published bench ruling in a Delaware case^[4] in which the court identified a doctor’s reliance on Waddell signs as constituting “proof of malingering” as one of several reasons underpinning its decision to exclude the doctor’s testimony.  In that context, the Delaware court noted that some medical experts, including Dr. Waddell, have cautioned against the use of Waddell signs for such a purpose.  The employee argues that this court should adopt similar reasoning to conclude that Dr. Engasser’s opinion was not competent evidence, because it was based in part on the presence of Waddell signs.

We note that Dr. Engasser based his opinion on more than just the presence of Waddell signs.  He also considered his objective examination findings and the employee’s medical history, including the observations of her treating physicians.  The doctor, similar to the compensation judge, considered the 17-month gap in medical treatment following the initial treatment for the 2010 injury.  Dr. Engasser considered this fact to be inconsistent with the employee’s claim of continued severe symptoms.

The employee has not provided any Minnesota case law to support the exclusion of Dr. Engasser’s opinion.  Evidence that physicians may disagree over how much use to make of Waddell signs does not constitute evidence that compels us to conclude that Dr. Engasser’s opinion should have been excluded from the record.

C.  Employee’s credibility.

The compensation judge states in her memorandum that she failed to find the employee credible with respect to her symptomology or with regard to the various reasons the employee gave at different times to explain why, despite testifying to severe ongoing pain, she did not seek any medical treatment over long intervals following the June 21, 2010, work injury.

The employee argues that the compensation judge’s assessment of the employee’s credibility was not reasonable or supported by substantial evidence.  She asserts that the compensation judge failed to take adequate consideration of evidence that corroborated that the employee had ongoing symptoms, including testimony of Mr. Kehl and medical findings in the treatment records.

The question of witness credibility is one that is uniquely within the province of the compensation judge as finder of fact.  Brennan v. Joseph G. Brennan, M.D., 425 N.W.2d 837, 41 W.C.D. 79 (Minn. 1988); Baker v. T. Maxwells, Inc., slip op. (W.C.C.A. Feb. 8, 2010).  It is not the function of this court to reevaluate the credibility and probative value of a witness’s testimony.  Even v. Kraft, Inc., 445 N.W.2d 831, 835, 42 W.C.D. 220, 225 (Minn. 1989); Redgate v. Sroga’s Standard Serv., 421 N.W.2d 729, 734 (Minn. 1988).  Although we might have viewed the question of credibility differently had we been the finder of fact, we see nothing in the judge’s credibility determination that requires a reversal by this court.

In January 2013, Dr. Lynn recommended a discogram to determine whether the employee might benefit from fusion surgery.  The compensation judge denied the proposed discogram in light of her findings that the employee’s 2010 injury had been temporary in nature and that the employee had failed to prove any of the three alleged 2012 dates of injury.  The compensation judge found that the discogram recommendation was causally related to the employee’s underlying degenerative spine conditions rather than to the effects of any new aggravating work injury.

The employee argues that the proposed treatment is diagnostic in nature and therefore is compensable on the theory that it might rule in or out some condition that could prove related to the work injury.  The compensation judge found that the employee sustained a single, temporary work injury, which had resolved no later than November 4, 2010.  She further found that the June 21, 2010, injury was not a contributing factor with respect to the necessity for a discogram.  We affirm.