The employer and insurer appeal from the judge’s finding as to the date of a claimed Gillette injury, his choice of expert opinions, and his reliance on the employee’s testimony.  We affirm in part and vacate in part.

The employee began working for Hitchin Rail [the employer] in October of 2003.  She started as a cook, but eventually her job was primarily waitressing, bartending, and supervising other workers.

On September 28, 2004, the employee sustained a work-related injury to her back while throwing heavy garbage bags into a dumpster.  She was initially treated conservatively but continued to have pain with radiculopathy into her right leg.  Dr. Joel Shobe interpreted a December 2004 MRI as showing a fairly large right-sided disc herniation at L5-S1.  He also noted some pre-existing degenerative changes above the L4-5 level, but he did not think those changes contributed to the employee’s pain.  On March 11, 2005, he performed a right L5-S1 microdiscectomy.

Dr. John Sherman performed an independent medical examination, and in a report dated April 22, 2005, he opined that the employee had sustained a low back strain in September of 2004 but then “had a spontaneous disc herniation” that was not secondary to any work activities.  Subsequently, on July 8, 2005, Dr. Shobe opined that the September 2004 work injury had caused the L5-S1 disc herniation.

The employee returned to work in her pre-injury job in the spring of 2005 and a few months later entered into a stipulation for settlement of claims for the 2004 work injury.  At the time of the stipulation, the employee was claiming entitlement to temporary total, temporary partial, and permanent partial disability benefits, rehabilitation benefits, and medical expenses.  The employer and insurer denied liability.  Under the terms of the stipulation, the employee was paid $11,000.00 for a full, final, and complete settlement, with the exception of future medical expenses.  An award on stipulation was filed on September 26, 2005.

In November of 2006, the employee treated with Dr. Shobe again for a flare up of low back, bilateral hip, and leg pain, reporting that she tried to limit her lifting at work but that it was not always possible.  Dr. Shobe recommended physical therapy and an MRI.  On December 22, 2006, before either could be completed, the employee slipped and fell at work.  The incident was witnessed by Allen Pomerleau, a co-owner of the employer.  On January 5, 2007, the employee presented to her primary care doctor, at the Bertha Clinic, for symptoms of an upper respiratory infection, but she also complained at that time of chronic back problems, commenting that her work as a waitress aggravated her symptoms.

A February 6, 2007, lumbar MRI was read as showing degenerative disc disease and facet arthrosis at L4-5 and L5-S1, with spondylolisthesis L4 on L5.  The employee was seen by Dr. Shobe on February 9, 2007, and his office note of that date referenced the slip and fall.  That note also indicated that the employee’s work involved heavy lifting, moving furniture, and vacuuming, and that her pain was aggravated by cooking, carrying things, lifting, and moving furniture.  Dr. Shobe again recommended physical therapy and also a lumbar injection.  He released the employee to work with restrictions on lifting and bending and directions to alternate sitting and standing.

The employee phoned the Bertha Clinic on February 15, 2007, complaining of severe low back pain and weakness in her legs.  According to the clinic notes, the employee felt that she was overdoing it at work.  The employee was given a note to take her off work that day, and she was subsequently taken off work again on March 5, 2007.^[1]  The employee did not work for the employer again after March of 2007.

The employee was seen on March 30, 2007, at Rich Prairie Chiropractic.  Office notes reference the fall on December 22, 2006, indicating also that the employee reached out with her left arm to grab the handle of the bar to stop her fall.  “While this stopped her fall it also jerked her arm and neck.”  The employee’s complaints on the date of this visit included mid-back pain, neck pain, and headaches.

June 5, 2007, office notes from the Bertha Clinic reflect that the employee was complaining of numbness and burning in her right arm.  When seen again on June 11, 2007, the employee complained of persistent neck pain and depression, and she stated that she felt her neck and arm pain had originated with the December 2006 fall.  An MRI performed on June 13, 2007, was read as showing disc herniations at C5-6 and C6-7.

Dr. Shobe’s June 22, 2007, office note indicated that the employee “has had difficulty with overhead work affecting her neck.”  On June 31, 2007, Dr. Shobe opined that the employee’s repetitive bending and lifting at work had aggravated her low back condition.  As of about July 9, 2007, the employee was advised to avoid overhead lifting.

The employee filed a claim petition on August 17, 2007, seeking various benefits as a result of specific injuries allegedly occurring on September 28, 2004, and December 22, 2006, and an alleged Gillette injury^[2] culminating in July of 2006.  On February 10, 2009, that claim petition was amended to include specific claims for permanent partial disability benefits and for permanent total disability benefits continuing from June 5, 2008.

The employee began part-time work at Friendly Inn in late August of 2007, waitressing, bartending, and cooking.  She worked there until June 4, 2008, when she was seen at her primary care clinic for a recheck of her depression.  The employee’s treatment until the end of 2008 focused on depression and anxiety.

Dr. Sherman performed another independent medical examination on February 13, 2008, and, in his report of that date, he indicated that the medical records did not corroborate the employee’s contention that she injured her neck in December of 2006.  It was his opinion that the employee did not sustain an injury in December of 2006 and also that there was no evidence of any Gillette injury.

The employee was examined by Dr. Robert Wengler on January 14, 2009, at the request of her attorney.  Dr. Wengler referred the employee for an MRI of the cervical spine, which indicated that the C5-6 disc herniation had increased slightly in size and that the facet arthropathy on the left at C4-5 had progressed.  On August 31, 2010, Dr. Wengler performed a C5-6 anterior discectomy and interbody fusion.  The procedure did not relieve the employee’s symptoms.

On April 2, 2009, Dr. Sherman issued an addendum report following review of updated records.  He concluded that the employee’s complaints were due to age-related degenerative changes and depression and that the employee had no work-related lumbar or cervical impairment.

Dr. Wengler’s deposition was taken on June 8, 2011.  He testified that the employee’s work activities after April of 2005 and/or her fall on December 22, 2006, were a substantial contributing cause of her lumbar and cervical spine conditions.  With regard to the employee’s cervical spine, he testified, “she probably whacked her head back in December and damaged the annular fibers of the disc, which ultimately became symptomatic to the extent that they were surgically treated.”  When asked to apportion responsibility between her work activities and the slip and fall, Dr. Wengler stated, “you can assign the responsibility to a Gillette injury . . . or you can assign responsibility to the specific injury that occurred when she fell and struck her head.”  “I don’t see that there’s going to make any difference one way or the other.”

The matter proceeded to hearing on October 12, 2011.  At the beginning of the hearing, counsel for the employee indicated that he was claiming benefits for a Gillette injury occurring in July of 2006 and a specific injury occurring on December 22, 2006.  The parties stipulated that the July 2006 injury date could be stricken, with the employee contending that it did not matter if there was a specific injury or a Gillette injury, that the operative injury date would be December 22, 2006, and that it was irrelevant if the injury was specific or Gillette.  The parties also stipulated that the employee was disabled on the dates claimed and that the employee had the claimed permanent partial disability.  The employer and insurer disputed, however, that there was any injury arising out of or in the course of the employee’s employment with the employer that was a substantial contributing cause of the employee’s disability or need for medical treatment.

In findings and order filed on December 23, 2001, the compensation judge determined that the employee had sustained a Gillette injury to her cervical and lumbar spine “arising out of and in the course of her employment in 2005 and 2006, which culminated on March 5, 2007, when the employee was taken off work,” and that the December 22, 2006, slip and fall further aggravated the employee’s cervical and lumbar spine condition.  He went on to find that the Gillette and the specific injury both caused the employee’s need for medical treatment and disability.  The employer and insurer appeal.

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 (2010).  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).

The employer and insurer contend that the judge’s adoption of Dr. Wengler’s medical opinions was clearly erroneous because Dr. Wengler reviewed the employee’s medical history only briefly.  As such, the employer and insurer contend, Dr. Wengler’s opinion lacks foundation and is inadequate to establish causation.  We are not persuaded.

The employer and insurer argue specifically that Dr. Wengler did not mention the employee’s treatment with Anderson Chiropractic Clinic for back pain in the early 1990s or her treatment at Rich Prairie “only months before the September 28, 2004, work injury.”  However, at his deposition, it was disclosed that Dr. Wengler had been given four inches of medical records to review, and those records included the records of Dr. Anderson and Rich Prairie Chiropractic Clinic.  And, when asked whether he carefully reviewed all of those records, Dr. Wengler responded, “pretty much.”^[3]

A doctor need not comment on every medical record that he or she reviews in preparation for rendering an opinion.  In this case, the records of Dr. Anderson mention only four treatments in the years 1990, 1992, and 1993, and the Rich Prairie Chiropractic Clinic records reflect nine treatments in the year preceding September 28, 2004.  Dr. Wengler testified that he was aware of chiropractic treatments to the employee’s neck and low back during those periods.  We note also that while Dr. Sherman mentioned these records in his report, he did not appear to find them important, in that his ultimate opinion was that the employee suffered from “age appropriate degenerative changes.”

A judge’s choice between expert opinions is generally upheld unless the facts assumed by the expert in rendering his opinion are not supported by the evidence.  Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  Dr. Wengler reviewed the employee’s medical records, examined the employee, and took her medical history.  As such, he clearly had adequate foundation for his opinion.  See Grunst v. Immanuel-St. Joseph Hosp., 424 N.W.2d 66, 40 W.C.D. 1130 (Minn. 1988).  The employer and insurer have not established that Dr. Wengler assumed that the employee had no low back or neck complaints prior to her work injuries, nor have they alleged any other fact assumed by Dr. Wengler that was not supported by the evidence.  We find no lack of foundation or other basis to overturn the judge’s decision to rely on Dr. Wengler’s opinions.^[4]

The employer and insurer contend that “the employee’s inconsistent testimony and lack of treatment for her alleged work-related injuries fail to prove the necessary causal relationship.”  We are not persuaded.

Both Dr. Wengler and Dr. Sherman noted that the employee’s recollections of her past medical history were inconsistent, and both doctors described the employee as a poor historian.  And it is true that the employee failed to seek medical treatment for the December 22, 2006, injury until she saw Dr. Shobe for her low back on February 9, 2007, and she failed to seek medical treatment for neck symptoms related to the 2006 slip and fall until she sought chiropractic treatment on March 30, 2007.  However, the December 22, 2006, incident was witnessed by Mr. Pomerleau,^[5] and his wife testified that the employee complained of back pain on February 2, 2007.  Coworker Patricia Steery testified that, after the employee’s slip and fall, she observed the employee to hold her head differently, and there was a change in the employee’s ability to perform her job duties.  And Lori McKnight, the employee’s daughter, testified that the employee complained of back and neck pain after December of 2006.

Credibility assessments are a unique function of the trier of fact.  Even v. Kraft, Inc., 443 N.W. 2d 831, 42 W.C.D. 220 (Minn. 1989).   We find no basis to reverse the judge’s award of benefits based on the employee’s inconsistent testimony or lack of immediate medical treatment after the December 22, 2006, incident.  The evidence noted above, independent of the employee’s testimony, along with the opinion of Dr. Wengler, provides substantial evidence to support the judge’s conclusion that the employee sustained a work-related injury to her neck and low back on December 22, 2006, and we affirm that finding.

The compensation judge found that the employee sustained a Gillette injury to her cervical and lumbar spine culminating on March 5, 2007, when the employee was taken off work.  The employer and insurer argue that it was improper for the compensation judge to have selected March 5, 2007, as the date of injury because that injury date was never claimed, that “the employer and insurer were denied due process of law and the claim would be barred because of lack of notice and the claimed injury date is beyond the statute of limitations.”

After reviewing this appeal, this court wrote to counsel for both parties asking why the date of the Gillette injury was of any importance, given the judge’s finding of a specific injury occurring on December 22, 2006.^[6]  The employee’s attorney responded by noting that the date of the Gillette injury was of no importance.  The employer and insurer’s attorney did not directly answer the question.  In any event, Dr. Wengler, whose testimony the compensation judge adopted, “lumped” both the Gillette injury and the slip and fall on December 22, 2006, together in finding causation for both the employee’s cervical and the employee’s lumbar conditions.  The compensation judge specifically found that “the Gillette injury and the December 22, 2006 slip and fall caused the need for additional medical care to the lumbar spine and permanently aggravated the employee’s previous lumbar spine condition” and “caused the need for treatment to the cervical spine, the eventual need for the surgery to the cervical spine . . . and resulting permanent impairment of the cervical spine.”  As we have affirmed the judge’s finding as to a specific injury on December 22, 2006, the exact date of the employee’s Gillette injury is irrelevant, and we vacate the judge’s finding on that issue.  Our decision to this effect, however, in no way changes the employer and insurer’s liability for benefits.  Because the December 22, 2006, injury substantially contributed to the employee’s disability and need for treatment, the judge’s award is affirmed.