The self-insured employer appeals from the compensation judge’s determination that although the exact anatomical cause for the employee’s left shoulder symptoms is unknown, her original October 2009 work injury is a substantial contributing cause in her ongoing symptoms, and the disputed treatment is reasonable, necessary, and causally related to the work injury.  We affirm.

The employee, Deborah Bogdanowicz, was 58 years old at the time of the hearing in this matter.  She has a history of progressing multiple sclerosis.  The employee testified that her lower extremities are primarily affected by the condition.  The employee said that her upper extremities were “not really” affected by multiple sclerosis, other than some numbness in her fingers.  The employee had also been referred by her multiple sclerosis specialists for some treatment and diagnostics, including an MRI scan, relating to her neck.  She has never been told multiple sclerosis affected her neck specifically in any way.

The employee did have some prior chiropractic treatment for her neck.  According to the employee, her neck symptoms related to a possible need for a breast reduction.  The employee said that she stopped taking a certain medication and lost several pounds, which reduced her neck symptoms.  She also had a history of prior work-related injuries involving her lower back and right shoulder.  She had not had any previous injuries affecting her left shoulder.

The employee began to work for the self-insured employer, Target Corporation, in August 2009.  She worked part-time as a cashier.  The employee sustained the injury that is the subject of this litigation on October 3, 2009.  While working as a cashier, the employee was holding a 24-pack of water when she began to lose her balance.  She quickly twisted from right to left to place the 24-pack on a counter.  During that movement, she felt a small “pop” in the area of her left shoulder blade, but she did not feel any immediate pain.  The injury occurred toward the end of the employee’s shift.  Later that day, however, the employee’s left shoulder pain began to increase.

The self-insured employer initially admitted the employee’s injury.  Eventually, the employer began to deny certain treatments based, in part, on its position that the employee’s ongoing symptoms and need for treatment were no longer related to the employee’s October 2009 injury.  The employee then filed the medical request that is the subject of this matter.

The employee testified that before October 3, 2009, she had never had any problems with her left shoulder.  In an unappealed finding, the compensation judge noted that before October 3, 2009, the employee’s left shoulder did not limit her activities in any way.

The employee began a short course of conservative care with her primary physicians at the Allina Clinic shortly after her injury in October 2009.  She was diagnosed with a left shoulder strain.  The employee underwent an MRI scan on the left shoulder in early December 2009, which was read as unremarkable.

On January 5, 2010, the employee had a left shoulder injection.  As of January 18, 2010, the employee was reporting that her symptoms remained unchanged, and she had persistent left shoulder pain.

The employee was eventually referred to an orthopedic surgeon, Dr. L. Pearce McCarty, III.  She first saw Dr. McCarty on March 25, 2010, and he referred the employee for evaluation by a cervical spine specialist to address whether her ongoing shoulder pain was attributed to cervical issues.  The specialist reportedly determined that there was not anything wrong with the employee’s neck and felt that the employee’s symptoms were originating in the shoulder.  The employee underwent a shoulder injection in May 2010.  She also returned to see her multiple sclerosis specialist on July 6, 2010, and he recommended that the employee undergo pain management.

The employee underwent an EMG of the left upper extremity at Noran Clinic on August 17, 2010.  This was interpreted as normal.  On August 23, 2010, the employee underwent a cervical myelogram and follow-up CT scan of the cervical spine.  These diagnostics showed degenerative findings and cervical spine atrophy, which were likely related to the employee’s multiple sclerosis.  There was no evidence of impingement.

The employee returned to see Dr. McCarty on September 24, 2010, and she underwent another left shoulder injection.  On October 26, 2010, the employee told Dr. McCarty that the injection had made her symptoms worse.  By that time, Dr. McCarty was diagnosing the employee with left shoulder stain and irritation of the brachioplexis.  Dr. McCarty felt there was no further treatment he could offer for the employee’s shoulder symptoms, and he recommended that she undergo a functional capacity evaluation.  After the functional capacity evaluation, Dr. McCarty saw the employee again on February 8, 2011, and he indicated that the employee had reached maximum medical improvement.  Dr. McCarty also recommended that the employee follow up with her neurologist for ongoing pain management.

The employee saw her multiple sclerosis specialist again in April and June 2011.  He referred the employee for a consultation with Dr. Andrew Will at the Twin Cities Pain Clinic.  The employee saw Dr. Will in September 2011.  Dr. Will recorded a history from the employee, including a discussion of her multiple sclerosis.  He opined that the employee’s shoulder pain was related to the employee’s shoulder injury and not to her multiple sclerosis.

On July 12, 2011, at the request of the self-insured employer, the employee saw neurologist Dr. James Allen for purposes of an independent medical examination.  Dr. Allen felt that based on the employee’s radiological scans and medical records, there were no objective findings to indicate any serious ongoing shoulder pathology, and he felt that the employee’s issues were related to her underlying multiple sclerosis.  Dr. Allen noted that the employee did sustain a mild left shoulder strain on October 3, 2009, but he felt that the injury had long since resolved and that the ongoing treatment had been excessive and unnecessary.  He noted that the employee’s multiple sclerosis was, “far and away the most significant contributing factor to her condition,” and he felt that the left shoulder strain was only temporary in nature.

The employee returned to see Dr. McCarty on November 29, 2011.  She was reporting a sharp increase in her left shoulder pain, and she had also noted a large bump on her back near the left shoulder area.  Dr. McCarty referred the employee for a diagnostic MR arthrogram of the left shoulder, which showed mild supraspinatus tendinopathy but ruled out any rotator cuff injury.  The employee testified that she had temporary relief from her symptoms due to the Novocain injection performed during the procedure.

On December 13, 2011, the employee was examined by orthopedic surgeon Dr. Edward Szalapski.  Following his examination, and review of the employee’s prior medical records, including multiple sclerosis records, Dr. Szalapski noted that the employee’s multiple sclerosis has been worsening.  He noted that early physical therapy records had referenced abnormal motion in the shoulder that was unrelated to any work injury but was likely attributable to her ongoing multiple sclerosis.  Dr. Szalapski felt that the employee had sustained a left shoulder strain on October 3, 2009, which was temporary, and which was not a substantial contributing cause to her need for medical treatment.  Rather, any ongoing need for treatment or care was due to the employee’s chronic multiple sclerosis.

The employee, at the request of her attorney, underwent an independent medical examination with Dr. Rupert Exconde.  Dr. Exconde issued a report dated March 15, 2012.  Dr. Exconde indicated that the October 2009 injury was a substantial contributing cause to winging in the scapula.  Dr. Exconde reviewed various medical records and a detailed hypothetical, which were submitted into evidence at hearing.  He also reviewed the reports from Dr. Allen and Dr. Szalapski.  Dr. Exconde believed that the October 2009 injury continued to play a substantial contributing role in the employee’s ongoing symptoms and need for medical treatment.  He felt that the treatment performed had been reasonable, necessary, and causally related to the October 2009 injury.

Dr. McCarty issued a narrative report dated March 18, 2012.  Prior to issuing his report, Dr. McCarty reviewed various medical records and was provided with a detailed hypothetical and background letter from the employee’s attorney.  This information was submitted into evidence at hearing.  Dr. McCarty also received copies of the prior reports from Dr. Allen, Dr. Szalapski, and Dr. Will.  Dr. McCarty noted that the employee never had a history of left shoulder discomfort or problems.  Dr. McCarty acknowledged that the employee’s “diagnosis is complicated by multiple sclerosis and, due to this fact, it is hard to interpret whether this is an exacerbation of her preexisting condition vs. a new onset left shoulder injury.”  Regardless of whether this was a new onset injury or an aggravation of a preexisting condition, though, Dr. McCarty opined that the injury in October 2009 was the type that could cause bony and/or soft tissue damage in the shoulder.  He felt that the employee’s physical exam history, findings, and diagnostic studies supported a diagnosis of left shoulder brachioplexis strain and impingement syndrome, and he opined that the employee’s ongoing treatment had been reasonable and necessary to treat that condition.

Dr. Allen gave a deposition on June 12, 2012.  Dr. Allen opined that the employee’s ongoing symptoms were not due to the temporary left shoulder injury of October 3, 2009.  Rather, he felt they were attributable to the employee’s long-standing multiple sclerosis.  For example, the employee’s scapular winging is a condition known to arise out of transverse myelitis due to multiple sclerosis.  This condition was evident in the employee’s case based on prior cervical MRI scans done before the employee’s work injury.  Dr. Allen testified that multiple sclerosis symptoms tend to wax and wane, and scapular winging can be known to arise spontaneously and then disappear suddenly.

The case came on for hearing on June 26, 2012.  The compensation judge noted that the left shoulder injury had been admitted and stated that

During opening arguments, counsel for the employee challenged Dr. Allen’s foundation because of his position that the employee had prior left shoulder problems or winging complaints.  Counsel for the self-insured employer argued that “this case is going to come down to a choice of experts, the employee’s or the self-insured employer’s.”  Counsel for the self-insured employer argued that substantial evidence would support Dr. Allen’s and Dr. Szalapski’s opinions.  Counsel for the self-insured employer, however, did not specifically challenge the foundation for any of the employee’s treating or evaluating physicians.

The compensation judge reviewed the medical records, physical therapy notes, and other evidence provided by the parties.  She noted that since the October 2009 work injury, the employee’s pain description has been “diffuse, making it difficult to identify the root cause of her left shoulder symptoms.”  The judge concluded that to the extent the employee had left scapular winging, that particular condition was not caused, aggravated, or accelerated by the work injury of October 3, 2009.  However, she concluded that although the exact anatomical cause of the employee’s left shoulder symptoms was unknown, the October 2009 work injury “is a substantial contributing cause in the symptoms that have led to the treatment at issue in this case.”  In particular, the judge felt that the work injury had been a substantial contributing factor “in the appearance and persistence of the employee’s left shoulder pain.”  She reached that conclusion “based on the timing of the appearance of the symptoms - - shortly after the work injury occurred, the chronicity of these symptoms since the work injury, and the opinions of Dr. McCarty and Dr. Will.”  As such, the compensation judge concluded that the employee’s ongoing treatment was reasonable, necessary, and causally related to the October 2009 injury.

In reviewing cases 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.  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, “[f]actfindings are clearly erroneous only if the reviewing court on the entire evidence is left with a definite and firm conviction that a mistake has been committed.”  Northern States Power Co. v. Lyon Foods Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).  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 the evidence or not reasonably supported by the evidence as a whole.”  Id.

The self-insured employer challenges the compensation judge’s finding that the employee’s October 2009 injury is a substantial contributing factor in the employee’s need for ongoing medical treatment.  In particular, it argues that Dr. McCarty and Dr. Will’s opinions are not supported by adequate foundation and that the employee’s multiple sclerosis, not the work injury, is the anatomical cause for the employee’s ongoing symptoms and need for treatment.

Foundation goes to the competency of a witness to provide an expert opinion, which is dependent on the witness’s scientific knowledge and practical experience with the subject matter of the offered testimony.  Drews v. Kohl’s, 55 W.C.D. 33, 37 (W.C.C.A. 1996), summarily aff’d (Minn. July 11, 1996) (citing Reinhardt v. Colton, 337 N.W.2d 88, 93 (Minn. 1983)).  However, counsel for the self-insured employer did not raise questions regarding the foundation for Dr. Will or Dr. McCarty’s opinions at hearing.  Rather, counsel for the employer argued that “this case is going to come down to a choice of experts, the employee’s or the self-insured employer’s.”  It is the function of the compensation judge to resolve conflicts in expert medical testimony, and his or her choice of expert opinion is usually upheld unless the facts assumed by the expert in rendering his opinion are not supported by the evidence.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).

Nonetheless, the employer argues that neither Dr. Will nor Dr. McCarty reviewed all of the medical records, including the prior treatment records regarding multiple sclerosis, and it argues that there are inconsistencies in Dr. McCarty’s diagnosis of the employee’s condition.  For example, the employer argues that Dr. McCarty did not reference the employee’s scapular winging, and it argues that Dr. McCarty did not discuss the potential contribution of her multiple sclerosis to her current symptoms and need for treatment.  Therefore, the employer argues that it was error to rely upon the opinions of Dr. Will and Dr. McCarty.

An expert need not express or even be made aware of every relevant fact for his or her opinion to have validity.  See Bossey v. Parker Hannifin, slip op. (W.C.C.A. Mar. 14, 1994).  A purported lack of information goes to the weight to be given to the medical opinion.  Schulenburg v. Corn Plus, 65 W.C.D. 237, 245 (W.C.C.A. 2005), summarily aff’d (Minn. May 25, 2005).  Sufficient knowledge of the subject matter can be obtained by personal knowledge, a hypothetical question, or testimony at the hearing.  See Scott v. Southview Chevrolet Co., 267 N.W.2d 185, 188, 30 W.C.D. 426, 430 (Minn. 1978).  Even where some facts may be unknown to a doctor, his or her opinions may still have sufficient foundation, as long as the omissions do not mislead the fact finder.  Drews, 55 W.C.D. at 39 (citation omitted).

Dr. Will was provided with a history by the employee, and Dr. McCarty was provided with a detailed hypothetical question, including a discussion of her underlying multiple sclerosis.  Dr. McCarty and Dr. Will were certainly aware of the employee’s pre-existing medical history and her symptoms, and they had each performed medical examinations.  We have stated on many occasions that this level of knowledge about the subject matter affords adequate foundation for a doctor to render an expert medical opinion.  See Johnson v. Micro Control Co., No. WC10-5206 (W.C.C.A. June 2, 2011) (citing Drews, 55 W.C.D. at 38-39).  Dr. McCarty and Dr. Will were sufficiently familiar with the employee’s past medical history, either directly or indirectly, to render a causation opinion.  See, e.g., Schulenburg, 65 W.C.D. at 244-45; Hillsdale v. Honeywell, Inc., slip op. (W.C.C.A. Feb. 6, 1997).

The self-insured employer also argues that because Dr. McCarty is an orthopedic surgeon and not a neurologist, he was not qualified to give an opinion regarding the employee’s current condition.  Exclusion of expert testimony lies within the discretion of the trial judge.  Reinhardt, 337 N.W.2d at 93 (citations omitted).  Again, counsel for the self-insured employer did not raise questions regarding Dr. McCarty’s qualifications at hearing.  Regardless, questions regarding the qualifications of an expert do not usually go to the admissibility of the expert’s opinion but merely to its weight.  Ruether v. State, Mankato State Univ., 455 N.W.2d 475, 477, 42 W.C.D. 1118, 1121 (Minn. 1990).  It is within the compensation judge’s discretion to assess the weight and sufficiency of a medical expert’s opinion.  Id. at 477-78, 42 W.C.D. at 1121-22.

There is no dispute that Dr. McCarty was qualified to evaluate the employee’s shoulder, which is the subject matter of the injury herein.  Rather, the employer bases its challenge to Dr. McCarty’s qualifications on his acknowledgement that the employee’s multiple sclerosis made her diagnosis more complicated.  Specifically, the employer argues that Dr. McCarty had “significant difficulty in determining whether the Employee’s ongoing symptoms are due to her temporary left shoulder strain, or whether they are due to her preexisting MS condition.”  We disagree with the employer’s characterization of Dr. McCarty’s opinion.  Dr. McCarty’s report states that the employee’s “diagnosis is complicated by multiple sclerosis and, due to this fact, it is hard to interpret whether this is an exacerbation of her preexisting condition vs. a new onset left shoulder injury.”  In other words, Dr. McCarty opined that the employee did sustain an injury to her shoulder, and whether it was a new injury or an aggravation of her preexisting condition, that injury has not resolved.^[1]

It is apparent from the compensation judge’s findings and order, including her memorandum, that she carefully considered the arguments of the self-insured employer, the discussions of scapular winging, and the employee’s underlying multiple sclerosis.  The compensation judge was aware of the medical experts’ backgrounds, which Dr. Allen discussed at his deposition, and she provided a detailed rationale for her determination that the employee’s “work injury is a substantial contributing factor in the appearance and persistence of the employee’s left shoulder pain.”  As such, we are unable to say that the compensation judge was somehow “misled” by any of the opinions of the medical experts involved.^[2]

In addition to its arguments regarding foundation and qualifications of the medical experts herein, the self-insured employer argues that the employee’s ongoing symptoms and need for treatment are related to her multiple sclerosis.  Therefore, it argues that because the treatment and medical benefits at issue are not causally related to the October 2009 injury, they could not have been reasonable and necessary.

As the compensation judge pointed out at hearing, the critical issue here is medical causation, an issue almost always resolved by a judge’s choice between conflicting expert opinions.  Ultimately, the question becomes which medical expert the compensation judge finds more persuasive.  In Golob v. Buckingham Hotel, the Minnesota Supreme Court observed:

The employer argues that if there was no specific anatomical explanation for the employee’s current condition, as the compensation judge found, then the October 2009 injury could not be a substantial contributing factor in her ongoing condition or need for treatment.  A lack of specific diagnosis or anatomical explanation for the employee’s symptoms is not a bar to compensability.  See Wegner v. American Legion Post 50, No. WC11-5240 (W.C.C.A. June 22, 2011) (notwithstanding the lack of a clear anatomical explanation, substantial evidence supported the compensation judge’s choice to adopt the treating physician’s opinion that the work injury was a substantial contributing cause of disability and need for care).  The existence of a personal injury may be established based on an employee’s subjective complaints coupled with the opinion of a medical expert.  Brown v. State, Dep’t of Transp. 54 W.C.D. 60, 68 (W.C.C.A. 1996).  The issue is not the diagnosis of the employee’s condition but whether it was caused, aggravated, or accelerated by the employee’s work.  Wegner, No. WC11-5240 (citations omitted).

The employer relies heavily on the case of Durkee v. Starkey Labs, Inc., No. WC05-211 (W.C.C.A. Jan. 23, 2006) for the proposition that the employee’s ongoing symptoms and need for treatment are related to her multiple sclerosis and not her October 2009 injury.  In Durkee, this court upheld a determination that a work injury was no longer a substantial contributing cause in the employee’s ongoing need for benefits.  There, the compensation judge relied upon Dr. James Allen’s opinion that the employee had recovered from her injury and that her ongoing issues were related to chronic degenerative issues caused by multiple sclerosis.  In affirming the compensation judge’s decision in Durkee, we noted that there was evidence that could support the employee’s contention that her work injury remained a substantial contributing factor.  However, the issue before this court was not whether the evidence may support a conclusion different from the compensation judge but whether substantial evidence existed to support the judge’s findings.^[3]  Because there was evidence to support the judge’s finding that the employee’s work injury was temporary, we affirmed.

Here, as indicated in her findings and order and accompanying memorandum, the compensation judge based her determination on the appearance and persistence of the employee’s symptoms after the October 2009 injury, the medical opinions of Dr. Will and Dr. McCarty, the employee’s lack of positive response to conservative treatment, and clinical findings discussed in the medical records.  This evidence led the compensation judge to the conclusion that the employee’s injury remained a substantial contributing factor in her need for treatment.  Because substantial evidence supports the compensation judge’s conclusion, we affirm.