STATE OF MINNESOTA

                                 IN SUPREME COURT

                                        A14-2065

Workers’ Compensation Court of Appeals                                        Gildea, C.J.

David J. Mach, Jr.,

              Respondent,

vs.

Wells Concrete Products Co., and CCMSI,

              Relators,

and                                                                  Filed: July 22, 2015
                                                               Office of Appellate Courts
Blue Cross Blue Shield, Operating Engineers
Local 49 Health & Welfare Fund,

              Intervenors.
                              ________________________


Eric W. Beyer, Falsani, Balmer, Peterson, Quinn & Beyer, Duluth, Minnesota, for
respondent.

Janet Monson, Amy M. Mahowald, Aafedt, Forde, Gray, Monson & Hager, P.A.,
Minneapolis, Minnesota, for relators.

                              ________________________

SYLLABUS

       1.     A claim for payment of medical expenses incurred to treat a work-related

injury is not barred by res judicata if the right to seek reimbursement for those expenses

had not arisen at the time of the previously denied claim.


                                             1
      2.     A claim for payment of medical expenses incurred to treat a work-related

injury is not barred by collateral estoppel if the facts establish that the employee’s

condition has changed since the time of the previously denied claim.

      Vacated and remanded.

OPINION

GILDEA, Chief Justice.

      We are asked to determine whether res judicata or collateral estoppel bars

respondent’s workers’ compensation claim. The compensation judge concluded that the

claim was barred, but the Workers’ Compensation Court of Appeals (“WCCA”) reversed.

We agree that res judicata does not apply, but because we conclude that whether

collateral estoppel bars respondent’s claim depends on whether his condition has

changed, we vacate the decision of the WCCA and remand to the compensation judge.

      This action arises from an injury that respondent David J. Mach sustained to his

left leg while employed by Wells Concrete Products Co. (“Wells”). Mach was working

as a crane operator when an auger on the back of a skid steer detached and struck Mach

in the left leg. There is no dispute that the injury was work-related, resulted in lasting

pain, and required medical treatment. Mach experienced chronic pain and discomfort

after the injury, and underwent significant medical treatment, including MRIs, physical

therapy, knee surgery, and dozens of evaluations.

      In August 2010 Mach sought compensation under the workers’ compensation

laws. He filed a claim petition seeking disability benefits and compensation for medical

expenses (“2010 claim”). Most relevant here, Mach claimed that as a result of his work


                                            2
injury, he developed reflex sympathetic dystrophy (“RSD”), now known as complex

regional pain syndrome (“CRPS”), and that he was entitled to compensation for medical

expenses, including expenses incurred for the implantation of a spinal cord

neurostimulator. Mach also claimed temporary partial disability benefits from June 7,

2010 through September 20, 2010, temporary total disability benefits from September 21,

2010 through the date of the hearing, and permanent partial disability benefits due to his

CRPS. Wells admitted that Mach suffered an injury in the course of his employment but

denied that Mach had CRPS, that the neurostimulator was compensable medical

treatment, and that Mach had any restrictions on his work activities.

       The compensation judge determined that some of the disputed medical bills,

including those for an x-ray, an MRI, and several clinic visits, were reasonable and

necessary treatment for Mach’s injury, and awarded compensation for those expenses.

But the judge concluded that Mach failed to show that he suffered from CRPS and that

the neurostimulator was a reasonable medical treatment for Mach’s work injury. The

judge rejected the medical opinion of Mach’s doctor, who had recommended placement

of the neurostimulator, and instead adopted the opinions of two independent medical

examiners, who had concluded that Mach did not have CRPS and that a neurostimulator

was not a reasonable or necessary treatment. The judge therefore denied Mach’s claims




                                             3
for treatment related to the neurostimulator. 1 The WCCA affirmed this denial. Mach v.

Wells Concrete Prods. Co., 72 Minn. Workers’ Comp. Dec. 91, 107 (WCCA 2012).

       Mach subsequently underwent surgery to remove his neurostimulator and replace

it with a new one. Mach filed a second request for medical benefits on October 7, 2013,

seeking compensation for the expenses related to the replacement (“2013 claim”). To

support his 2013 claim, Mach submitted a letter from Dr. Paul J. Vollmar, who began

treating Mach on January 16, 2012.         Dr. Vollmar concluded that Mach “has and

continues to have complex regional pain syndrome of the left leg” and that this condition

“is directly related to the [work] injury.” Dr. Vollmar said that Mach “has [a] spinal cord

stimulator in place which will need to be periodically interrogated by a manufacturer’s

representative and reprogrammed. Since this is a battery operated electronic unit at some

point in the future it will probably need to be revised or replaced.”

       Wells moved to dismiss the 2013 claim, arguing that Mach’s claim for benefits

was barred by res judicata and collateral estoppel. Specifically, Wells argued that the

2013 claim was barred because the necessity of a spinal cord neurostimulator had already


1
       As to the disability ratings, the compensation judge denied Mach’s claim for total
temporary disability benefits, finding that any inability to work after September 21, 2010
was due to either a low-back condition unrelated to Mach’s work injury, or to Mach’s
personal wishes. The judge also denied Mach’s claim for permanent partial disability,
finding that Mach had failed to establish the CRPS criteria necessary for a permanency
rating. The judge granted Mach’s claim for temporary partial disability benefits from
June 7, 2010 to September 20, 2010. The WCCA affirmed the denial of temporary total
and permanent partial disability benefits and vacated the award of temporary partial
disability benefits after Mach conceded on appeal that he could not prove that his
physical condition was the cause of his wage loss during that period. Mach v. Wells
Concrete Prods. Co., 72 Minn. Workers’ Comp. Dec. 91, 105, 108 (WCCA 2012).


                                              4
been considered and rejected by the compensation judge and the WCCA.                 The

compensation judge granted the motion to dismiss.       The judge determined that the

removal and replacement of the neurostimulator “represent[ed] maintenance and/or a

continuation of treatment found non-compensable” by the litigation of Mach’s 2010

claim. The judge concluded that Mach “failed to show in the previous proceedings that

the implant of the Medtronic pain stimulator” was related to his work injury, and

therefore held that an attempt to relitigate that issue with a new claim for benefits was

barred by res judicata and collateral estoppel.

       The WCCA reversed. Mach v. Wells Concrete Prods. Co., 

, at

*3 (Minn. WCCA Nov. 4, 2014). The court held that “Dr. Vollmar’s bills were not

before the judge in [the 2010 claim] and are therefore not precluded by the previous

decision.” 

 The court noted that none of the compensation judge’s findings on the

2010 claim established that Mach’s work injury was temporary, had healed, or had

resolved.   

   Because those “findings and order covered only claims for medical

expenses prior to January 5, 2011, and the current claim is for medical expenses from and

after January of 2012,” the court held that Mach’s 2013 claim was not barred by res

judicata or collateral estoppel. 

 The court therefore remanded the 2013 claim to the

compensation judge for a determination on the merits. 

 Wells petitioned for certiorari

review under 

 (2014).




                                              5
                                            I.

       The appeal involves res judicata and collateral estoppel. As related doctrines, res

judicata and collateral estoppel are sometimes used interchangeably, even though each

doctrine has a distinct effect. Hauschildt v. Beckingham, 

 (Minn.

2004). The application of the doctrine of res judicata is a question of law that we review

de novo. Care Inst., Inc.-Roseville v. Cty. of Ramsey, 

 (Minn.

2000). The application of collateral estoppel is a mixed question of law and fact that we

also review de novo. 

       The workers’ compensation system in Minnesota is a creature of statute. See

Minn. Stat. ch. 176 (2014).     The statutes do not address res judicata or collateral

estoppel. 2   But we have held that “principles of res judicata” apply to workers’

compensation proceedings. Westendorf v. Campbell Soup Co., 

,

 (1976). We have also recognized that these principles do not

preclude the litigation of claims and issues that were not specifically decided in a prior

proceeding. See 

, 

; Fischer v. Saga Corp., 

 (Minn. 1993). With this background in mind, we turn to an analysis of whether

either res judicata or collateral estoppel precludes Mach’s 2013 claim.


2
       Minnesota Statutes § 176.461 provides a right for either party to reopen and seek
modification of a workers’ compensation award. Mach does not ask to set aside any part
of the decision on his 2010 claim; rather, he seeks an award of compensation for new
medical expenses, a scenario which chapter 176 does not expressly address. Wells also
does not seek to set aside an award, because Mach received only an award of past
medical expenses in the first proceeding. Accordingly, section 176.461 is not applicable
here.


                                            6
                                            II.

       We first consider whether res judicata precludes Mach’s 2013 claim. Alternately

called “claim preclusion” or “merger and bar,” res judicata is a finality doctrine that

applies “when a subsequent action or suit is predicated on the same cause of action,” or

claim, that has been previously determined by a judgment.              Hauser v. Mealey,

 (Minn. 1978). A subsequent claim is precluded when “a prior

claim involved the same cause of action, there was a judgment on the merits, and the

claim involved the same parties or their privies.” Nelson v. Am. Family Ins. Grp.,

 (Minn. 2002). A cause of action or claim is “a group of operative

facts giving rise to one or more bases for suing.” Hauschildt, 

(quoting Martin ex rel. Hoff v. City of Rochester, 

 (Minn. 2002)). Claims

are not considered the same cause of action if “the right to assert the second claim did not

arise at the same time as the right to assert the first claim.” Care Inst., Inc., 

. The common test for determining whether an action is precluded is to determine

“whether the same evidence will sustain both actions.” McMenomy v. Ryden, 

, 

 (1967). Additionally, “the party against whom res judicata

is applied must have had a full and fair opportunity to litigate the matter in the prior

proceeding.” Nelson, 

. Res judicata is not applied rigidly but is a

“flexible doctrine” in which “the focus is on whether its application would work an

injustice on the party against whom estoppel is urged.” Johnson v. Consol. Freightways,

Inc., 

 (Minn. 1988).




                                             7
       Mach’s claim for reimbursement of medical expenses is precluded by res judicata

only if it involves the same claim or cause of action that was previously decided. Mach’s

2013 claim seeks compensation for the implantation of a spinal cord neurostimulator; the

compensation judge denied a claim for similar medical treatment in the 2010 claim. The

WCCA correctly noted, however, that the findings and order in the 2010 claim covered

only a claim for expenses incurred for treatment received prior to January 5, 2011. Mach,

, at *3. Mach’s 2013 claim is for expenses incurred for treatment

received in January 2012 or later. 3 

 Specifically, Mach’s 2013 claim includes an

April 18, 2012 procedure to replace his neurostimulator. Logically, Mach could not have

requested reimbursement for these 2012-and-beyond treatment expenses in the 2010

claim, because the procedure had not yet occurred and the expenses had not been

incurred.

       In the context of the workers’ compensation system, these differences preclude

application of res judicata. This is so because employers have ongoing liability for

treatment of work-related injuries. That liability continues until the effects of an injury

are cured or symptoms are relieved.        See 

, subd. 1(a) (“The

3
        Because his previous claims were denied, Mach has no current disability rating
and is not receiving income benefits under 

, and his current claim
does not allege that he should receive such benefits. Minnesota Statutes § 176.135, subd.
1(a), however, provides that an employer must furnish an employee with treatment to
“cure and relieve from the effects of the injury.” Nothing in the statute requires an
employee to be receiving disability benefits in order to be compensated for ongoing
medical expenses incurred to cure and relieve the effects of an injury. See 8 Arthur
Larson et al., Larson’s Workers’ Compensation Law § 94-01[3] (Matthew Bender rev. ed.
2015) (“[I]t seems clear that liability for medical benefits should not be diminished by the
fact that, for some reason, income benefits are not payable.”).


                                             8
employer shall furnish” care and treatment “as may reasonably be required at the time of

the injury and any time thereafter to cure and relieve from the effects of the injury.”); see

also Gamble v. Twin Cities Concrete Prods., 

 (Minn. 2014) (noting

that an employer is responsible for ongoing medical treatment if the employee sustains an

injury arising out of and in the course of employment and medical treatment is reasonably

required to cure and relieve the effects of the injury). Mach’s 2013 claim—that as of

2012 he needed a procedure to replace his neurostimulator to cure and relieve the effects

of his work injury—falls within the scope of the employer’s ongoing statutory liability

for medical treatment. As Larson’s Workers’ Compensation Law states, “[i]t is almost

too obvious for comment that res judicata does not apply if the issue is the claimant’s

physical condition or degree of disability at two entirely different times.” 12 Arthur

Larson et al., Larson’s Workers’ Compensation Law § 127.07[7] (Matthew Bender rev

ed. 2015).

       Because Mach’s 2013 claim is for treatment expenses incurred after the previous

decision, the operative facts are not the same, and different evidence supports each claim.

The 2013 claim, therefore, is not the same as Mach’s 2010 claim for purposes of res

judicata, and we hold that res judicata does not preclude Mach’s 2013 claim.

                                            III.

       Even if not precluded by res judicata, Mach’s claim may still be precluded by

collateral estoppel. Collateral estoppel, also called “issue preclusion,” applies to specific

issues that have previously been adjudicated. Hauschildt, 

. Under this

doctrine, “once a court has decided an issue of fact or law necessary to its judgment, that


                                             9
decision may preclude relitigation of the issue in a suit on a different cause of action

involving a party to the first case.” Allen v. McCurry, 

 (1980). Collateral

estoppel applies to matters that were necessarily determined in a previous judgment,

“irrespective of whether the subsequent action is predicated upon the same or a different

cause of action.” Hauser, 

. Collateral estoppel applies when: “(1) the

issue was identical to one in a prior adjudication; (2) there was a final judgment on the

merits; (3) the estopped party was a party or in privity with a party to the prior

adjudication; and (4) the estopped party was given a full and fair opportunity to be heard

on the adjudicated issue.” Nelson, 

 (quoting Willems v. Comm’r of

Pub. Safety, 

 (Minn. 1983)). Like res judicata, we “do not apply

collateral estoppel rigidly,” but focus on whether an injustice would be worked upon the

party against whom the estoppel is urged. 

 The party asserting collateral estoppel has

the burden to establish that “the issue was actually presented and necessarily determined

in the earlier action.” Lange v. City of Byron, 

 (Minn. 1977).

      There is no dispute that the prior workers’ compensation adjudication on Mach’s

2010 claim was a final judgment, involved the same parties, and that Mach had a full and

fair opportunity to be heard. The only question is whether the issues are identical. See

Nelson, 

.

      In the 2010 claim, the compensation judge determined that a spinal cord

neurostimulator was not reasonable medical treatment necessitated by Mach’s work

injury. As part of that determination, the compensation judge found that Mach had failed

to show that he suffered from CRPS. Wells argues that the same issue—whether a


                                           10
neurostimulator represents reasonable medical treatment necessitated by a work injury—

is presented by Mach’s 2013 claim, in which he again seeks compensation for a spinal

cord neurostimulator to treat CRPS. Mach argues, on the other hand, that the issues are

not identical because “the benefits claimed are for a different period of time.” He argues

that the compensation judge erred when he failed to consider Dr. Vollmar’s explanation

for why a neurostimulator was reasonable in 2012 or whether there was any “change in

circumstances.” In essence, Mach argues that the reasonableness of neurostimulator

treatment in 2010 is a different issue than the reasonableness of neurostimulator treatment

in 2012, because the conditions relevant to the determination of reasonableness may

change or worsen over time, and that therefore collateral estoppel does not apply.

       Mach’s assertion finds support in the ongoing nature of an employer’s liability in

workers’ compensation cases to provide all medical treatment necessary at the time of the

injury “and any time thereafter” in order to “cure and relieve” the employee from the

effects of the injury. 

, subd. 1(a). The compensation judge in the

2010 claim did not find that Mach was cured or that the effects of his injury were

relieved; rather, the judge found that Mach did not have CRPS and that a neurostimulator

was not reasonable or necessary treatment for his injury. Mach’s argument suggests that

the effects of his injury may have changed and that treatment that was not reasonable and

necessary at the time of the 2010 claim may now be reasonable and necessary.

       We recognized a similar principle in the context of a workers’ compensation claim

for disability benefits in Saenger v. Liberty Carton Co., 

 (Minn. 1982).

There, we held that a previous determination that an employee was not totally disabled,


                                            11
but had voluntarily retired and withdrawn from the labor market, did not preclude the

employee from later showing that a substantial change in his condition thereafter had left

him totally disabled. 

. We held that finality principles applied “only to the

factual determinations that, as of [a previous date, the] employee was not totally disabled

and had then retired and voluntarily withdrawn from the labor market.” 

 These

principles did not, however, “preclude [the] employee from showing that since that date

he has become totally disabled and that at some point after [the previous date], but prior

to becoming totally disabled he decided again to obtain gainful employment.” Id.; 4 see

also Lindberg v. J & D Enters., 

 (Minn. 1996) (“[W]hat is required is

proof of the actual existence of a disability during the period of time for which benefits

are claimed.”).

       We reach the same conclusion in this case. Just as in Saenger, collateral estoppel

does not apply to bar a claim for reimbursement of medical expenses for treatment

received when an employee’s medical condition has changed. The compensation judge,

in denying the 2010 claim, determined that Mach had failed to show that the effects of his

work-related injury included CRPS and therefore necessitated a neurostimulator. Absent

a change of condition or new facts, Wells should not be forced to undertake the expense



4
      We recognize that our decision in Saenger speaks in terms of res judicata.

. The analysis nevertheless applies to our discussion of collateral
estoppel because the employee in Saenger attempted to show that the issue of whether he
was totally disabled at a later date had not been litigated because his condition had
changed. Id.; see Hauschildt, 

 (noting that res judicata and collateral
estoppel are sometimes used interchangeably).


                                            12
of relitigating the matter and collateral estoppel would bar the 2013 claim. 5 But in

resolving the 2013 claim, the compensation judge did not determine whether Mach’s

medical condition has changed or new material facts have emerged, and we cannot

discern the answer to that question based on the record before us. 6        Because this

determination is necessary in order to resolve whether collateral estoppel precludes

Mach’s 2013 claim, further proceedings are required. We therefore vacate the decision

of the WCCA and remand to the compensation judge for further proceedings consistent

with this opinion.

       Vacated and remanded.




5
       Although the burden is on the employee to prove that he is entitled to benefits,
Fischer v. Saga Corp., 

 (Minn. 1990), the burden is on the employer
to prove the affirmative defense of collateral estoppel, City of Byron, 

.
6
       Mach did not directly argue to our court that his condition had changed since the
hearing on his 2010 claim. But in the letter attached to Mach’s medical request,
Dr. Vollmar noted some symptoms that, according to the compensation judge’s findings
on the 2010 claim, were not observed by the doctor who prescribed Mach’s original
neurostimulator. These symptoms include changes in skin color, temperature, and motor
disability. The relevance of these changes can be determined in the proceedings on
remand.


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