The employee appeals from the compensation judge’s finding that her 1999 work injury was not a substantial contributing factor to her current condition, disability, and need for treatment.  We reverse.

The employee, Debra Heisick, has suffered from chronic low back issues since a motor vehicle accident in 1975, but has otherwise maintained an active lifestyle.  On May 20, 1999, while working for Zurich North America Insurance Company (Zurich) as an attorney, the employee sustained an injury to her low back in a motor vehicle accident.  An MRI showed a small left-sided disc herniation at L5-S1 compressing on the left S1 nerve root, with degenerative changes at L4-5, and mild degenerative changes of the facet joints.  The employee declined to undergo a microdiscectomy at L5-S1.  Three years later, surgery was recommended by Dr. Thomas Bergman. The employee again declined surgery and continued conservative treatment, including a MedX lumbar program at Physicians Diagnostic and Rehabilitation.

In 2008, the employee sought medical treatment for a flareup of low back pain.  She was diagnosed with piriformis syndrome and physical therapy was recommended.  The physical therapy resolved the piriformis syndrome symptoms, but not her right leg symptoms.  In February 2011, she was seen for right buttock and leg pain which had begun a few weeks prior with no new injury.

In August 2011, the employee was diagnosed with cauda equina syndrome.  She underwent a right L5-S1 hemilaminectomy and microdiscectomy on September 1, 2011, performed by Dr. Bergman.  Following surgery, she reported resolution of right buttock and posterior leg pain, but ongoing inner thigh numbness.  An MRI in January 2012 showed that the large disc herniation at L5-S1 had been removed, but a small disc bulge with enhancing scar tissue encasing the traversing nerve roots remained, as well as advancing degenerative changes at L4-S1.^[1]

Dr. Bergman issued a Health Care Provider Report on May 9, 2012, indicating that the employee had reached maximum medical improvement (MMI), and rated the employee with 11 percent permanent partial disability (PPD) as to her low back.

In April 2013, the employee settled her claims against Zurich on a to-date basis and closed out PPD benefits to the extent of 21 percent.  The employee continued to have flareups of her low back and radicular symptoms which were managed with conservative treatment, including physical therapy and injections.  She continued to consult with medical providers, including Dr. Bergman.

In April 2018, the employee underwent an MRI which showed stenosis at L3-4, increased nerve impingement at L5-S1 due to the increased size of the disc protrusion, mild central stenosis at L4-5, and increased edema in the L3-4 and L4-5 facet joints.  She saw Dr. Bergman in August 2018, reporting increased pain in her buttocks and right leg, and numbness in the left leg. Dr. Bergman reviewed the April 2018 MRI results and noted scar tissue at L5-S1, possibly from the 2011 surgery, but was unable to identify the cause of her symptoms.  The employee continued conservative treatment.

In 2017, the employee began working for the State of Minnesota, Department of Labor and Industry (DOLI).  On June 9, 2023, the employee attended a lengthy ceremony during which she shared a chair with a colleague.  Her low back hurt following the ceremony.  She presented at urgent care a few days later with severe burning pain and numbness down her left leg and into her knee, as well as pain in both sides of her low back and right buttock.  A June 18, 2023, lumbar MRI showed a new large disc herniation with free fragment and spinal stenosis at L4-5, along with severe central stenosis and recess foraminal stenosis at L3-4, unchanged from the 2018 MRI.

On August 8, 2023, the employee underwent a microdissection and bilateral extended hemilaminectomy, medial facetectomy, foraminotomy, and decompression of the L5 nerve root bilaterally, performed by Dr. Mahoud Nagib.  Dr. Nagib stated in his operative note that there was no free fragment, and instead, the L5 nerve root compression was the result of a thickened ligamentum flavum.  The employee returned to work and although the surgery relieved some symptoms, she continued to experience daily pain and occasional flareups.

Dr. Wicklund performed an examination and issued a second report dated November 23, 2023.  At that time, it was his opinion that the employee sustained an injury while sitting in a crooked position on June 9, 2023, and that this injury was the only substantial contributing cause to the development and progression of the nerve root compression at L4-5 found during the August 2023 surgery.  As such, he declined to apportion liability for the employee’s condition.

Following a record review, Dr. Larkins issued a report dated November 4, 2024.  He attributed 100 percent of the L4-5 pathology to sitting awkwardly in a chair on June 9, 2023.  Dr. Larkins further stated that the employee’s prior L5-S1 complaints were not a substantial contributing factor to her L4-5 disc injury as they were on opposite sides and on different levels.

At the request of the employer DOLI, Dr. Jeffrey Dick examined the employee and issued a report dated January 16, 2024.  Dr. Dick opined that the employee did not sustain an injury on June 9, 2023, from sitting in an awkward position.  Instead, he noted that the employee’s condition and need for surgery in 2023 was the result of nerve compression from a hypertrophic ligamentum flavum, a common cause of spinal stenosis and radicular pain.  In discussing what causes this condition he stated that it “occurs very slowly over many years and is part of the normal aging process.”  (Ex. 3 at 17.)  He also stated:

Dr. Wicklund issued a third report on October 7, 2024, noting that there was validity to Dr. Dick’s opinion that the surgery at one level could lead to more rapid disc degeneration at an adjacent level.  He agreed with Dr. Dick’s opinion that 25 percent of the need for treatment at the L4-5 level in 2023 was attributable to the 2011 surgery at L5-S1 and to the 1999 work injury.

The employee filed a claim petition seeking payment of medical bills, wage loss benefits, out-of-pocket expenses, medical mileage, and intervention claims related to the 2023 surgery.  The matter was heard by a compensation judge at the Court of Administrative Hearings on April 23, 2025, who issued a Findings and Order on September 5, 2025. 

With regard to the 1999 work injury, the compensation judge stated that the injury was a permanent aggravation of the employee’s pre-existing low back condition, and was the cause of the employee’s need to undergo surgery in 2011.^[2]  She found that MMI had been reached no later than August 20, 2012, and that the employee sustained 11 percent permanency as a result of that injury.  With regard to the claimed injury of June 9, 2023, the compensation judge found that the employee did not sustain an acute work-related low back injury on that date, relying on the opinions and medical records of Dr. Dick and Dr. Nagib.  Finally, the compensation judge found that neither the admitted 1999 work injury nor the alleged 2023 injury was a substantial contributing factor to the employee’s current condition, disability, or need for treatment, and thus denied the employee’s and intervenors’ claims in their entirety.  The employee appeals.

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(3).  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).  When the findings are supported by substantial evidence, the Workers’ Compensation Court of Appeals must defer to the compensation judge. Lagasse v. Horton, 982 N.W.2d 189, 202 (Minn. 2022).  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); see also Smith v. Carver Cnty., 931 N.W.2d 390, 79 W.C.D. 495 (Minn. 2019).

A decision which rests upon the application of a statute or rule to essentially undisputed facts generally involves a question of law which the Workers’ Compensation Court of Appeals may consider de novo.  Krovchuk v. Koch Oil Refinery, 48 W.C.D. 607, 608 (W.C.C.A. 1993), summarily aff’d (Minn. June 3, 1993); see also Busch v. Advanced Maint., 659 N.W.2d 772, 778-79 (Minn. 2003).

The employee appeals the compensation judge’s finding that the 1999 work injury was not a substantial contributing factor to her current condition, disability, and need for treatment, arguing this finding is clearly erroneous and must be reversed.

The employee sustained a work-related injury to her low back in 1999 in the nature of a herniated disc at L5-S1, and later developed cauda equina syndrome for which she underwent surgery in 2011.  The compensation judge concluded that the 1999 work injury was a permanent aggravation and was the cause of the employee’s need for surgery in 2011.  (Mem. at 19.)  The employee suffered a worsening of her low back condition in 2023.^[3]  She underwent surgery at the L4-5 level performed by Dr. Nagib, who noted compression of the L5 nerve root as a result of a thickening of the ligamentum flavum.  (Ex. F.)

The compensation judge, relying on Dr. Dick’s opinion, found that the employee’s need for surgery in 2023 was not causally related to the 1999 work injury.^[4]  Instead, she determined that the employee’s L4-5 stenosis developed and worsened over time, stating, “there is no medical record or opinion that attributes the thickening of the ligamentum flavum … to the 1999 injury.”  (Mem. at 19.)  She further reasoned that, according to Dr. Dick, thickening of the ligamentum flavum occurs very slowly over many years and is part of the aging process.

On appeal, the employee argues that these assertions made by the compensation judge in support of her finding that the 1999 work injury is not causally related to her current condition are clearly erroneous.  We agree that the compensation judge misconstrued Dr. Dick’s causation opinion, rendering her basis for this finding internally inconsistent and factually erroneous.

It is well established that a compensation judge is free to reject or accept all or a portion of a medical expert’s opinion.  See Klasen v. Am. Linen, 52 W.C.D. 284, 292 (W.C.C.A. 1994), summarily aff’d (Minn. Mar. 16, 1995).  “A compensation judge generally is free to accept a portion of an expert’s opinion while rejecting other portions.”  Johnson v. L.S. Black Constr., Inc., slip op. (W.C.C.A. Aug. 18, 1994) (citing City of Minnetonka v. Carlson, 298 N.W.2d 763 (Minn. 1980)).  This court has affirmed decisions in which a compensation judge accepted a medical expert’s opinion with regard to one issue, and rejected that same opinion with regard to another issue.  See, e.g., Cuevas v. Rainbow Foods #51, slip op. (W.C.C.A. Mar. 25, 2004) (compensation judge accepted medical expert’s opinion with regard to causation but rejected that expert’s opinion with regard to compensability of chiropractic treatment); see also Leonard v. Yellow Freight Sys., Inc., slip op. (W.C.C.A. Aug. 18, 2003) (compensation judge accepted medical expert’s opinion with regard to MMI but rejected that expert’s opinion with regard to need for work restrictions).

In this case, the compensation judge relied on a portion of Dr. Dick’s opinion that contradicts his overall causation conclusion in finding that the aging process was the sole cause of the employee’s current condition.  This is an erroneous reading of Dr. Dick’s report. 

In his report, Dr. Dick answered a number of questions.  He was asked whether the employee’s claimed injury of June 9, 2023, was a substantial contributing factor to her current low back condition.  In response, Dr. Dick indicated that injury was not a factor, stating:

Dr. Dick was also asked whether the 1999 work injury continued to be a substantial contributing factor to the employee’s current low back condition, need for treatment, and disability.  Dr. Dick responded:

Dr. Dick was also asked to apportion liability for the employee’s current low back condition.  In response, Dr. Dick apportioned 75 percent of the pathology at the L4-5 level to the normal aging process and 25 percent to the disc herniation at L5-S1 that occurred as a result of the 1999 work injury.  As to the L5-S1 level, he apportioned 75 percent to the 1999 work injury, and 25 percent to the normal aging process.  (Ex. 3 at 17, 20.)  Dr. Dick stated:

Reading Dr. Dick’s report as a whole, he opined that the employee’s current condition was caused by both the aging process and by the 1999 work injury.  The compensation judge accepted the opinion of Dr. Dick, but misstated his opinion on causation and reached a conclusion that is entirely inconsistent with his opinion.  This case does not present the scenario of an acceptance of an opinion by a compensation judge on one issue and rejection of that opinion on another issue, as in Klasen and its progeny.  Dr. Dick’s opinion does not support the compensation judge’s finding that the employee’s admitted 1999 injury was not a substantial contributing factor of her current low back condition.  The compensation judge’s statement that there is no medical record or opinion to support causation between the 1999 work injury and the employee’s current condition, and her determination that the need for the 2023 surgery was caused solely by the aging process, are clearly erroneous and manifestly contrary to the evidence.

Furthermore, substantial evidence in the record does not otherwise support the compensation judge’s finding that the employee’s current condition is not related to her 1999 work injury.  The only medical expert opinions that opposed the causation opinion of Dr. Dick were those of Dr. Larkins, whose opinions were not adopted by the compensation judge, and the initial opinions of Dr. Wicklund, which later changed and aligned with that of Dr. Dick.  All other medical opinions pre-date the employee’s 2023 flareup and surgery and are not relevant to the issue of causation for the employee’s current condition.  The compensation judge’s finding that the employee’s current condition is not causally related to her 1999 work injury is not supported by evidence a reasonable mind might accept as adequate.  Accordingly, Finding 64 is reversed as to the 1999 work injury.

Given our reversal of this finding, we also consider whether the evidence supports a finding that the 1999 work injury is a substantial contributing cause of the employee’s current condition.  See Lagasse v. Horton, 982 N.W.2d 189, 201 (Minn. 2022) (the WCCA may substitute a compensation judge’s explicit finding when that finding is unsupported by substantial evidence of record).

We conclude that the evidence supports a finding of a causal relationship between the 1999 work injury and the employee’s current condition.  The opinion of Dr. Dick, which the compensation judge found most persuasive, supports causation.  Dr. Dick explained in detail how the 1999 work injury was related to the need for surgery in 2023.  The most recent report of Dr. Wicklund also supports causation, as Dr. Wicklund reviewed and agreed with the opinions of Dr. Dick.  Further, as set forth in several of the compensation judge’s unappealed findings, the employee testified at hearing that she has had chronic low back pain and numerous flareups since 1999, and that although her symptoms had waxed and waned, they had not fully resolved.^[5]

As the causation opinion of Dr. Dick is accepted in its entirety, we find that the employee’s 1999 work injury is a substantial contributing factor to her current condition, disability, and need for treatment.  The employee’s claims for wage loss, medical treatment, additional 14 percent permanency, and the intervention claims related to her 2023 surgery and current condition, are awarded.