The employee appeals from the compensation judge’s determination that his claimed work injuries were temporary aggravations and that he was not permanently totally disabled.  We affirm.

Richard Hoch was born in December 1952.  In December 1987, he went to work for the Duluth Clinic as a custodian.  He was employed in that position, cleaning offices, until he stopped working on April 20, 2004.^[1]

Medical records in evidence disclose a history of low back problems for the employee before his first work injury in October 1991.  In February 1988, he sought treatment for, among other complaints, discomfort in the left buttock radiating into his left leg.  He reported that it had been a particular problem for the previous two weeks and seemed to be aggravated by the vacuuming he did on the job.^[2]  The employee treated for his low back pain in 1990.  In November 1990, he reported to his doctor that he had chronic right leg and low back pain for two or three years and that he could not identify a precipitating event.  The lumbar CT scan done in January 1991 showed a herniated disc at L4-5.  A referral was made for a surgical consultation; the recommendation was for continuing conservative care unless neurological changes were noted.  In addition to treating at the Duluth Clinic, the employee also treated with a chiropractor, Dr. Robert Torgrimson, who also diagnosed a herniated disc at the L4-5 level.

The employee sustained a work injury to his low back on or about October 30, 1991.  In his testimony at the hearing he was unable to provide any information as to when or how the injury happened or any information as to his symptoms after the injury.  In a letter written by the employee’s treating doctor, Dr. Peter Person, on November 19, 1991, it was noted that the employee had been admitted to the hospital for severe pain following shoveling snow.  The employee was hospitalized for some days in November 1991.  An MRI of the lumbar spine done on November 4, showed a central herniated disc at L4-5.  The employee continued to treat conservatively for his low back symptoms, including chiropractic care from Dr. Torgrimson.  In a letter to Dr. Person, Dr. Torgrimson noted “the patient had done quite well and I have dismissed him from his work related injury from this office without restrictions or residuals.  I do not believe that he has suffered any permanency as a result of this injury according to the Minnesota Workers’ Compensation Guidelines.  I do feel that the patient does has a tendency to blame any ache and pain on his work related injury.  I have explained to him that he will have periodic discomfort with some of his personal and work activities however they are unrelated to the injury in question.”

On May 18, 1992, Dr. Person reported the employee was able to work at his full duties.  A notice of benefit payment filed by Hartford, the employer’s insurer, on November 6, 1992, indicated that the employee was paid 3.4 weeks of temporary total disability benefits between November 4 and November 30, 1991 and was paid 9% permanent partial disability.  The basis for the payment of permanent partial disability is not noted on the NOBP.

The employee reported a low back injury occurred on December 7, 1993.  The employee could not provide any detail about the injury at the hearing but a chart note from the Duluth Clinic dated December 8, 1993, stated the employee had the onset of low back pain when he leaned over to pull a case of toilet paper along the floor.  The employee was given work restrictions and he treated with Dr. Torgrimson.  He missed no time from work and was considered by Dr. Torgrimson to be at pre-injury status as of January 27, 1994.  The employer and its insurer, Acuity Group, paid medical expenses related to the injury.

From 1995 until 2002, the employee treated for bilateral shoulder problems and right elbow problems; treatment which included surgery in 1997 and 2000.  Although the employee claimed at the time that his shoulder and elbow conditions were the result of a work injury or injuries, he made no claim at the hearing in this matter that the shoulder condition or the elbow condition were substantial contributing factors in his claimed permanent total disability.  The employee also treated throughout his employment with Duluth Clinic for diabetes.  The employee had been diagnosed with diabetes when he was 11 or 12 years old.

The employee had an MRI of the lumbar spine on January 22, 2004.  It was read as showing “all visualized discs are normal for age except for the L4-5 level where there is moderate DJD and a moderate size central to left side disc extrusion and moderate anterior dural sac deformity.  There is mildly asymmetric left lateral recess narrowing and impingement of the L5 root but no frank trapping.  L4-5 foramina appear patent.”

On March 26, 2004, the employee reported to the employer that he had injured his back on November 1, 2003, while lifting a recycling bag at work.  In addition to low back pain complaints, the employee also referred to having pain in his thoracic spine.  The employee did not miss any time from work as a result of this claimed 2003 injury.

On March 12, 2004, the employee consulted with Dr. Matthew Eckman for his mid and low back pain.  There were no positive findings on examination other than mild tenderness at T9-10 and bilateral straight leg raising at 60 degrees.  Dr. Eckman had no treatment recommendations other than that the employee should continue with pain medication and he encouraged the employee to taper his prescription medications and try “plain Tylenol.”  Dr. Eckman also stated “he will be able to continue working in his usual job as a custodian at the Duluth Clinic without restrictions beyond common sense.” On April 14, 2004, Dr. Alan Peterson, the employee’s treating internal medicine physician, prepared a “report of workability” for the November 3, 2003, injury in which he released the employee to work with no restrictions.

The employee stopped working for the Duluth Clinic on April 20, 2004, claiming subsequently that he was unable to keep working because of his back condition.  The employee has not worked anywhere else since he left the Duluth Clinic and he has not engaged in any sort of job search or return-to-work activities.

On May 11 and 12, 2004, Dr. Peterson prepared disability claim forms for the employee.  The medical condition identified by Dr. Peterson which led to the employee’s disability were “type 1 diabetes, lumbar disc disease, chronic lumbar and thoracic back pain, neuropathy.”  Dr. Peterson indicated the employee was permanently disabled.  In a letter of July 25, 2004, written in support of the employee’s claim for Social Security disability benefits, Dr. Peterson stated “I feel he is disabled for work by virtue of having decades long history of juvenile onset diabetes, peripheral neuropathy and lumbar disc disease.  He has been fatigued as a result of difficult to control diabetes.”

In a workability report prepared by Dr. Eckman on October 11, 2004, the employee was identified as being retired.  In the chart note for that visit, Dr. Eckman stated “he has been retired from his work, and I do think he would have a great deal of trouble doing an adequate job as a custodian with its varied physical demands there.” An MRI was done of the thoracic spine on October 25, 2004, and was read as negative other than showing mild mid-thoracic arthritis.

At the request of the employee’s attorney, Dr. Eckman prepared a report setting forth his opinion on permanent partial disability.  In his February 3, 2005, report, Dr. Eckman rated the employee as having 12% permanent partial disability under Minn. R. 5223.0390 for a herniated disc with sciatica and an additional 2.5% under 5223.0380 for the thoracic spine.  Asked about causation, Dr. Eckman stated “from the information available to me, his lower thoracic and lumbar spine problems were substantially aggravated by his work as a custodian at the Duluth Clinic over the years.  I am not aware of other significant injuries.  The major episode was October 30-November 2, 1991 as a significant factor with some gradual deterioration subsequently as he continued his duties and further aggravated the problem.”  The self-insured employer for the November 1, 2003, injury paid the 9.5% disability for the low back rated by Dr. Eckman.

The employee filed a claim petition in April 2005, which was later amended.  As of the date of the hearing, the employee was claiming permanent total disability from April 20, 2004, as well as payment of additional permanent partial disability.  His claims were against the Duluth Clinic/Hartford for the October 30, 1991, injury, against Duluth Clinic/Acuity Group for the December 7, 1993, injury, and against Duluth Clinic/Self-Insured for the November 1, 2003, injury and for a claimed Gillette injury of April 20, 2004.

The employee was evaluated on behalf of Hartford by Dr. William Akins on October 13, 2005.  Dr. Akins took a history from the employee, reviewed medical records, performed an examination and set forth his conclusions in his November 3, 2005, report.  Noting the extensive records of a preexisting condition and the lack of a consistent history of an incident on October 30, 1991, Dr. Akins stated “it is my opinion that there is great doubt as to whether a work related injury took place on October 30, 1991 or not.  It is my opinion that the majority of medical evidence indicates that it did not.”  In any event, Dr. Akins was of the opinion that the claimed October 30, 1991, work injury represented, at most, a six month temporary aggravation of the preexisting condition.

On behalf of Duluth Clinic/Acuity, the employee was evaluated by Dr. Larry Stern on December 2, 2005.  Dr. Stern limited the conclusions in his report to the effects of the December 7, 1993, work injury.  He concluded that the employee did not sustain any permanent injury to his low back at that time and that any strain the employee had sustained was resolved by January or February 1994.

Dr. Nolan Segal evaluated the employee for Duluth Clinic/self-insured on January 20, 2006.  As was true for the other evaluations, the employee was unable to provide a history about any of his claimed work injuries.  In 36 pages of his report, Dr. Segal detailed the medical records dealing with the employee’s medical conditions.  Dr. Segal concluded “it is my opinion, based upon a reasonable degree of medical certainty, that his musculoskeletal problems, in fact, were likely not a result of any of his work activities or alleged injuries.”  Specifically, Dr. Segal stated that there was no November 1, 2003, injury but any such injury would have been a temporary injury which resolved in three months.  He also stated there was no evidence of a 2004 Gillette injury.

The employee’s claims were heard by Compensation Judge Gregory Bonovetz on August 30, 2006.  At the hearing, the attorneys for all three of the employers/insurers advised the compensation judge of their position that either there had been no work injuries to the employee’s back or that the injuries in 1991, 1993 and 2003 were temporary aggravations of the employee’s preexisting condition.  The 1991 and 2003 insurers stated that payments made of permanent partial disability were made under a mistake of fact.  The insurers also stated their common position that the employee was capable of employment and was not permanently totally disabled.

In his findings and order of December 4, 2006, the compensation judge determined that the claimed 1991, 1993 and 2003 injuries were temporary aggravations, that there was no 2004 Gillette injury, and that at no time since April 20, 2004, had the employee been permanently totally disabled as a result of one or more work injuries.  The employee appeals.

The employee argues that the compensation judge erred in finding the 1991 and 2003 injuries to be temporary.  According to the employee, the compensation judge’s denial of permanent total disability was based on this finding and since the finding of temporary injuries was in error, the employee should be awarded permanent total disability.  We disagree.

The employee notes that primary liability for both injuries was accepted and permanent partial disability was paid for each injury.  According to the employee, acceptance of primary liability and payment of benefits are admissions of liability which are binding in future proceedings.  As authority, the employee cites to the decision by this court in Roemhildt v. Gresser Companies, No. WC06-105 (W.C.C.A. Aug. 23, 2006).

We do not believe Roemhildt stands for the proposition argued by the employee.  In Roemhildt, this court dealt with the issue of whether an amendment to Minn. Stat. § 176.221 modified case law and the provisions of Minn. Stat. § 176.151 that a voluntary payment of benefit constitutes a proceeding which tolls the statute of limitations.  We held that this rule was not modified by the statutory amendment.  While Roemhildt reaffirmed the tolling of the statute of limitations by a voluntary payment of benefits, the decision did not state that a voluntary payment of benefits precludes the employer from subsequently arguing that the payment was made under a mistake of fact.

Further, in Roemhildt, this court specifically noted the supreme court’s decision that an employer may deny primary liability for an injury, in the absence of prejudice to the employee, after making a voluntary payment of benefits.^[3]  Zontelli v. Smead Mfg. Co., 343 N.W.2d 639, 36 W.C.D. 453 (Minn. 1984).  In Christianson v. Axel H. Ohman Construction Co., 346 N.W.2d 654, 36 W.C.D. 639 (Minn. 1984), the court dealt with the procedure to be followed in applying Minn. Stat. § 176.179 in recovering an overpayment of benefits after the employer claimed payment of benefits was made under a mistake of fact.  We find the statute and the case law to be authority for an employer to change its position and deny liability even though there has been a voluntary payment of benefits.

The employee further argues that the payment of benefits and the acceptance of payment by the employee constitute a settlement which binds the employer in the future.  However, for a settlement to be an adjudication which affects future claims, it must be approved pursuant to Minn. Stat. § 176.521.  Nothing of the sort was done here.

We conclude there was no legal impediment in this case to prevent the compensation judge from determining that the 1991 and 2003 injuries were temporary injuries.  The attorneys representing the employer for the 1991 and 2003 injuries were very clear in advising the compensation judge and the employee’s attorney of their position that the injuries were temporary.  Whether the injuries were temporary or were, instead, substantial contributing factors in the employee’s present condition was properly before the compensation judge for determination.

Substantial evidence supports the compensation judge’s finding that these injuries were not substantial contributing factors in the employee’s claimed inability to work and were temporary injuries.  We see no reason to restate all of the evidence on this issue.  We would refer to the opinions of the IME doctors, the lack of a persuasive medical opinion in support of the employee’s claim, and the medical records.

Finally, we address the employee’s contention that there was no finding that the employee was not permanently totally disabled.  It is not the compensation judge’s function to make an abstract assessment of an injured worker’s employability.  The question for the compensation judge is whether the claimed work injuries have resulted in permanent total disability.  The compensation judge made a specific finding on this issue and determined that the employee was not permanently totally disabled as the result of any work injury.  (Finding 32)  Substantial evidence supports this finding.

The decision of the compensation judge is affirmed.