The employee petitions to vacate an award on stipulation served and filed January 3, 2007, on the grounds of newly discovered evidence, mutual mistake, and an unanticipated substantial change in medical condition.  We conclude the employee has not established cause as required by Minn. Stat. § 176.461 and the petition is denied.

Daniel S. Leach worked for the employer, Ulland Brothers, as a heavy equipment operator.  He was injured on a road construction project on July 1, 2005, when he was "clipped" by a passing motor vehicle as he was standing near some equipment while waiting for it to cool down.

He was evaluated that same day at the Albert Lea Clinic for possible injury to the neck, chest, mid back, and low back.  Tenderness was noted throughout much of his back, but neurological testing was unremarkable and he was diagnosed with a back contusion.  X-rays done the same day showed no acute abnormality, although there were minimal diffuse degenerative changes at the low back and cervical spine.

On July 5, 2005, the employee returned to the Albert Lea Clinic in follow-up.  He now complained of intense pain primarily in the right lower back with some radiation and numbness into his right leg.  The employee was taken off work and told to return in about a week.  On July 11 the employee was seen again and complained of pain in the lower lumbosacral area, more on the right than left.  He reported occasional radiating pain into the right buttock and leg.  Straight leg raising was negative.  The employee was off work until late July when he returned to work for the employer in a light duty job weighing trucks at the employer's quarry.^[1]

On October 2, 2005, the employee was evaluated for the employer and insurer by Dr. David Fey.  The employee complained of persistent constant low back pain radiating into his right buttock and posterior thigh to the knee.  Except for slight tenderness in the employee's left lower back and a decreased range of lumbar extension, the employee's examination was essentially normal. He concluded that the employee had sustained a mild lumbar soft tissue strain which should have resolved within eight weeks of the injury.  The employee reported having recently had a lumbar MRI scan showing a bulging disc.  Dr. Fey did not have the MRI report to review, but noted that the employee's complaints of decreased sensation into the right lateral foot were consistent with a possible right lower extremity radiculopathy.  However, because there were no objective findings to support such a diagnosis, he thought it likely that any disc bulge was related solely to the employee's preexisting lumbar degenerative disc disease.  He considered the employee to have reached maximum medical improvement without permanency or any need for restrictions.

Dr. Fey was subsequently provided with the employee's MRI report and issued a supplementary report on November 9, 2005.  He noted that the MRI showed degenerative disc disease at multiple levels of the lumbar spine and a posterior disc bulge at L5-S1, without definite herniation.  The doctor did not think there was any support for a diagnosis of radiculopathy as stenosis was also absent.  Dr. Fey related the disc bulge to the preexisting degenerative disc disease.

On January 26, 2006, the employee's family practice physician, Dr. Lonnie Berger, provided a report to the employee's attorney.  He diagnosed multilevel degenerative disc disease, a posterior disc bulge at L5, and a sprain/strain in the lower lumbar spine.  Despite physical therapy, pain clinic consultation, and epidural and trigger point injections, the employee continued to complain of lower back and leg pain without significant relief.  Dr. Berger noted the employee had continuing restrictions but was tolerating working and driving a vehicle.  He considered the work injury to have been a substantial contributing factor in the employee's disability and to have aggravated the employee's preexisting degenerative changes in the spine.  Because the employee had failed conservative care, Dr. Berger recommended a neurosurgical consultation with Dr. David Beck in Mason City.

The employee was seen by Dr. Beck on February 15, 2006.^[2]  Dr. Beck recommended that the employee undergo a myelogram to evaluate possible nerve root impingement, particularly at the L5-S1 level.  The employee underwent the myelogram on March 8, 2006.  Dr. Beck subsequently wrote a letter in which he stated that the myelogram results did not explain the employee's pain.  After seeing the employee in follow-up, Dr. Beck recommended the employee have an EMG study.  The EMG report of March 29, 2006, is said to have shown right sciatic neuropathy without active axonal degeneration and no evidence of radiculopathy.  According to Dr. Fey’s report, the doctor who performed the EMG stated that “there was clinical evidence of right piriformis syndrome.”^[3]  There is no record of any response to the EMG or Dr. Fey’s report by the employee’s doctors, but, as noted previously, there are no treatment records before us.

In April 2006 a functional capacities evaluation was performed at the Albert Lea Medical Center.  The employee was found able to sit for six hours at a time and stand and walk for eight.  Bending, stooping, reaching above shoulder level, crouching, and kneeling were all subject only to slight restrictions and could be performed frequently.  Other motions tested, including pushing, pulling, balancing, squatting, crawling, and climbing were all ranked as “continuous” (i.e., unrestricted).  The employee was given lifting and carrying restrictions which allowed for frequent lifting of up to 40 pounds.  The only other restriction noted was that the employee should not use his right foot for the continuous operation of controls.

The employee was seen again for evaluation by the IME, Dr. Fey, on June 22, 2006.  Dr. Fey noted that the employee was currently on restrictions from his treating physicians of no lifting above 30-40 pounds and no prolonged sitting.  He was currently working at a light duty job for the employer.  The doctor noted that the employee continued to have an objectively normal exam. He reviewed the employee's updated records including the EMG report that suggested a possible sciatic nerve neuropraxia.  While he noted that such a condition could in fact result from being struck by a motor vehicle, he opined that the employee should then have had marked complaints of shooting pain down the right leg after the injury.  Since the emergency room report on the date of injury did not describe specific pain down the employee's thigh, he concluded that the employee had not sustained a sciatic nerve injury.  He saw no evidence that the employee's pain symptoms were related to any specific back pathology.  Dr. Fey concluded, “With the exception of the comments regarding a possible mild right sciatic nerve neuropraxia related to the motor vehicle accident of July 1, 2005, I have no change in my opinion since my previous report.”  In Dr. Fey's opinion, the employee needed no work restrictions other than sitting no longer than one hour at a time.

In his report of September 22, 2006, Dr. Berger noted that while the emergency room records on the date of injury were very scant, and did not describe leg complaints, the records of Dr. Ulrich just a few days later showed that the employee was then complaining of pain into the leg area, specifically in a sciatic nerve distribution.  Dr. Berger concluded that the employee’s work injury contributed to his leg symptoms.  In his opinion, the employee's disc bulges at L5 were affecting the S1 nerve root.  While recognizing that degenerative changes were present prior to the injury, Dr. Berger believed that the traumatic injury to the lower back could have aggravated the preexisting problems at the L5 area.  He stated that the restrictions he had imposed, and those in the functional capacity evaluation, were reasonable and were necessitated in part by the work injury.  Dr. Berger rated the employee with 10% permanent partial disability as a result of the work injury, pursuant to Minn.R. 5223.0390, subp. 3.C.(2).

At some point during 2006, the employee's light duty job with the employer was terminated for reasons undisclosed in the record.

On December 6, 2006, the employee signed a stipulation for settlement agreeing to a full, final, and complete close out of all claims arising out of the July 1, 2005, work injury, including claims for future medical treatment, in return for a lump sum payment of $35,000.00.  The stipulation also capped the insurer’s subrogation claims arising out of the employee’s third party suit at $23,000.00 and waived any additional subrogation claim.  In the stipulation, the employee claimed entitlement to continuing temporary total and/or temporary partial disability benefits as well as an undetermined degree of permanent partial disability compensation, rehabilitation services, and potential future medical expenses.  The employer and insurer responded that the employee had sustained only a temporary aggravation to his low back and that he had been fully compensated for all workers' compensation benefits.  An Award on Stipulation was served and filed on January 3, 2007.

The employee was reevaluated on January 22, 2009, by Dr. Fey for the liability carrier of the driver of the car involved in his work injury.  The employee told the doctor that he still had persistent right low back pain with pain in the right buttock and posterior thigh radiating to the knee. After he stopped working for the employer, he had worked as a car salesman for a short period of time, but was currently not working.  He had permanent restrictions against lifting more than 40 pounds and was avoiding activity for fear of increased symptoms.  He was not receiving medical treatment and there were no records of any treatment since the settlement in 2006.  Examination revealed tenderness diffusely about the right buttock, most prominently in the area of the piriformis muscle, just medial to the posterior aspect of the greater trochanter.  Lumbar extension was full and straight leg raising was negative.

Dr. Fey reconsidered his prior diagnosis, and stated it was “reasonable at this point to consider the possibility that Mr. Leach has a diagnosis of posttraumatic right piriformis syndrome.” He noted that this diagnosis “certainly can occur after a blunt trauma to the right low back/buttock area consistent with Mr. Leach’s described injury of July 1, 2005.”  The doctor also noted that a diagnosis of piriformis syndrome was raised by the physician performing the EMG in March 2006.  Dr. Fey suggested that the employee undergo a diagnostic right piriformis injection.  If the injection reduced the employee's pain, Dr. Fey thought the employee could need physical therapy treatment and perhaps a referral to a neurosurgeon for “consideration of possible definitive treatment including right piriformis release surgery.”  He concluded that a piriformis syndrome, if confirmed, would be causally related to the work injury.

The employee returned to the Albert Lea Clinic where he was seen by Dr. Michael D. Ulrich on February 16, 2009.  He had not been seen there since March 24, 2006, when he had last treated with Dr. Berger.  According to the employee, he had been unable to work since that time.  The employee told Dr. Ulrich about Dr. Fey's suggestion that he should receive a diagnostic injection to rule out a post-traumatic right piriformis syndrome.  Dr. Ulrich agreed that the employee's history and symptoms seemed consistent with a piriformis syndrome.  He referred the employee to the pain clinic for consideration of an injection.

On February 25, 2009, the employee was seen by Dr. Julian Waggoner at the Albert Lea Medical Center.  He reported that his pain started in the right or mid low back and radiated through the buttock and into the right posterior thigh to the knee.  There was tenderness over the right sacroiliac joint.  After, examination, Dr. Waggoner diagnosed myofascial pain, low back pain, sacroiliitis, sciatica, and piriformis syndrome.  The employee was given a piriformis muscle and sciatic nerve block injection.  On March 18, 2009, the employee returned to Dr. Waggoner reporting that his symptoms were 50% improved from the nerve block.  His pain was now centered in the right low back and buttock.  The employee was given a right sacroiliac injection.

The employee returned to see Dr. Ulrich in May 2009.  The employee continued to complain of low back pain, primarily on the right side with pain radiating into the right leg.  His examination was essentially normal, except for tenderness in the right SI joint area.  Dr. Waggoner, who saw the employee on June 3, 2009, noted that the employee’s pain had been continuing for three years and stated that the current condition would be his baseline.  He expected that the employee would continue to have waxing and waning of symptoms with no further significant improvement. On September 2, Dr. Waggoner diagnosed low back pain, myofascial pain, sacroiliitis, and piriformis syndrome.  Another right SI joint injection and a right piriformis muscle injection were done.  The employee was advised to perform activities only as tolerated.

On October 28, 2009, the employee petitioned this court to vacate the 2007 Award on
Stipulation on alternative grounds of a substantial change in medical condition, mutual mistake, or newly discovered evidence.  The employer and insurer responded opposing vacation as unwarranted.

This court’s jurisdiction to set aside an award is established by Minn. Stat. § 176.461. An award may be vacated for cause, identified in the statute as being limited to: 1) a mutual mistake of fact; 2) newly discovered evidence; 3) fraud; or 4) a substantial change in medical condition since the time of the award that was clearly not anticipated and could not reasonably have been anticipated at the time of the award.  The employee seeks to vacate the 2007 award on the basis of an unanticipated substantial change in his medical condition, newly discovered evidence, and mutual mistake.  We consider each of these grounds in turn.

In 2009, the employee's treating physicians added a diagnosis of piriformis syndrome to other diagnoses in explaining the employee’s low back condition.  The employee argues that this represents a change in his diagnosis from the time of settlement.  We disagree.  The doctor who performed the EMG on behalf of Dr. Beck in March 2006 stated that there was clinical evidence of right piriformis syndrome.  Dr. Fey referred to this conclusion in his June 2006 IME report.  In the absence of the EMG report, or of any records from Dr. Beck, or of any treatment records from the Albert Lea Clinic, we are unable to ascertain to what extent the diagnosis of piriformis syndrome was considered before the settlement.  However, it seems clear that at the time of the settlement, the employee’s doctors had concluded that the employee had sustained an injury which had resulted in sciatica as the primary symptom.  The current diagnosis, which includes piriformis syndrome, represents a different label for the same sciatic nerve symptoms that were well-documented prior to the settlement, at which time they were attributed solely to a possible radicular impingement of the sciatic nerve within the spine itself.  We find no change in diagnosis.

We next consider whether there has been a change in the employee's ability to work.  The employee alleges in his affidavit that, at the time of the settlement, he had relied on the opinions of the various physicians in the case, as well as the FCE findings, in concluding that he would be able to return at least to moderate duty work.  The employee further claims that he has not been able to return to work since the date of the settlement, and that he is unable to perform any competitive work on a full time basis.  However, the employee was not working as of the date of the settlement and in that regard his condition has not changed.  Further, the restrictions placed on the employee by the FCE in April 2006 would have permitted him to engage in work with moderate restrictions and the employee has not submitted any evidence showing that his restrictions are more severe at this time or that he is unable to work.  The employee has stated he is unable to work but there is nothing in the medical records which would support that assertion.  The employee has not provided us with sufficient medical or vocational information to support a conclusion that there has been a substantial change in his ability to work since the time of settlement.

At the time of settlement, the employee was claiming 10% permanent partial disability based on the opinion of Dr. Berger.  The employee has neither alleged an increase in permanency nor submitted any medical opinion on this point.  This factor does not support a conclusion that there has been a substantial change in condition.

We next consider whether there has been a showing of a need for more costly and expensive medical care than was anticipated at the time of the stipulation.  The medical care provided in 2009, as a result of the diagnoses of piriformis syndrome, sacroiliitis, myofascial pain, and low back pain, had consisted of injections and physical therapy.  The treatment being provided now is not substantially different from that provided at the time of the settlement.  While Dr. Fey indicated that piriformis release surgery might become necessary if that diagnosis were confirmed, there has been no surgery recommendation.  There are no records suggesting that any additional or more extensive treatment might be appropriate now or at some time in the future.

The records submitted indicate that the employee’s present condition is related to the 2005 work injury.

In summary, the employee has failed to establish that there has been an unanticipated substantial change in his medical condition since the time of the settlement.  The employee’s claim rests on an argument that a diagnosis of piriformis syndrome was not made before the settlement.  As we have indicated, the evidence does not support this argument.  Even if we were to accept the argument that the diagnosis of piriformis syndrome represents a new diagnosis, the employee has failed to demonstrate any change in his ability to work, any additional permanent partial disability, or a need for more costly and extensive medical care.

To justify vacation of an award on stipulation on the grounds of newly discovered evidence, the evidence must have been in existence at the time of the settlement but not discoverable with the exercise of reasonable diligence; it must be relevant and admissible; it must not be merely cumulative or duplicative; and it must be such as to have had a reasonable likelihood of affecting the outcome.  Gruenhagen v. Larson, 310 Minn. 454, 246 N.W.2d 565 (1976); Greenwood v. Kamps, Inc., No. WC07-191 (W.C.C.A. Jan. 18, 2008).

The employee claims that the newly discovered evidence in this case is the diagnosis of piriformis syndrome.  The employee acknowledges that the underlying condition giving rise to this diagnosis was present at the time of the settlement but only when the diagnosis was made were the treating doctors aware that the injury would need additional treatment and would not resolve.

The employee’s arguments are not supported by the evidence here.  As we pointed out previously, the physician who performed the EMG for Dr. Beck stated in his report that there was clinical evidence to support a diagnosis of piriformis syndrome.  Dr. Fey referred to this potential diagnosis in his June 2006 report.  We do not know what the employee’s doctors did with this information but by no means can this be considered a “new” diagnosis.  Further, there is no evidence that at the time of settlement the employee’s doctors believed the employee’s condition would resolve.  In fact, in his September 22, 2006, report, Dr. Berger reaffirmed the employee’s need for work restrictions as the result of the work injury and also provided a rating of permanent partial disability.

We conclude the employee’s arguments on this issue do not meet the criteria set out by Gruenhagen and cause has not been established on the basis of newly discovered evidence.  The “new” diagnosis was not only discoverable but existed at the time of the settlement.  Further, there is no evidence that, if this diagnosis had been emphasized at that time, the settlement would have been affected in any way.

Finally, the employee claims that there was a mutual mistake at the time of the settlement as to the nature and severity of his injury.  He asserts that the parties were mistaken in that they believed he had only a sprain/strain injury and anticipated the injury would resolve fairly quickly.  He also contends that the parties mistakenly believed that he would be able to return to at least medium duty work.

To vacate a settlement on the basis of a mutual mistake, there must be a showing that the parties mutually misapprehended a fact material to the settlement, and the mistake must be documented as of the date of the settlement.  Shelton v. Schwan’s Sales Enters., 53 W.C.D. 110 (W.C.C.A. 1995); Flanagan v. Southern Minn. Constr. Co., 62 W.C.D. 221 (W.C.C.A. 2002).  A unilateral mistake by one of the parties does not meet the requirements of the statute.  Slaight v. Exceptional Homes, No. WC09-4999 (W.C.C.A. Feb. 10, 2010).

The record does not support a claim that both parties assumed that the employee had no more than a strain/sprain, or that the injury would resolve without residual disability.  It is true that Dr. Fey concluded the injury was a sprain/strain and the employee needed no work restrictions. However, the employee disputed that opinion and relied on Dr. Berger’s report in which he stated that the employee's work injury contributed to his leg symptoms, which were in a sciatic nerve distribution.  He also wrote that the injury might have aggravated preexisting degenerative changes in the low back and that disc bulges at L5 could be affecting the S1 nerve root.  He rated the employee with 10% permanent disability.  The employee has not shown a mutual mistake of fact with respect to his medical condition.  The differing opinions as to the employee’s medical condition demonstrate that there was no mutual agreement on this point.

It is not known from the record what the parties may have anticipated as to the employee's ability to return to work.  The employee alleged in the stipulation that he had restrictions from the work injury which would result in temporary total disability or temporary partial disability and he was not working at the time of the settlement.  In contrast, the employer and insurer alleged that the employee had no restrictions from the work injury and was not entitled to any further wage loss benefits.  The employee contends that he is now unable to work but there is no evidence that the employer has changed its position on this point.  We do not find any mutual understanding as to the employee’s ability to work, either at the time of settlement or at the present time.  The employee has not established a mutual mistake of fact.

The petition to vacate is denied.