THOMAS MANNING, Employee/Respondent, v. FLYNN ROOFING and RCI-MN, ADMINISTERED BY BERKLEY RISK ADM’RS CO., Employer-Insurer/Appellants, and TRUSTEES OF THE ROOFERS LOCAL NO. 96 H & W FUND, MIDWEST SPINE & BRAIN INST., TWIN CITIES ANESTHESIA ASSOCS., P.A., and MINN. DEP’T OF HUMAN SERVS., Intervenors.

The employer and insurer appeal the compensation judge’s finding that the employee had sustained a cervical spine Gillette^[1] injury and the corresponding award of benefits. We affirm.

Thomas Manning, the employee, has worked for various roofing companies for many years. This work involved heavy manual labor, including tearing off existing roofs and installing new roofs. The employee treated for left-sided neck and back pain in 2010. An imaging scan indicated the employee has a congenitally narrow cervical spinal canal in the mid and lower cervical regions. He was assessed as having moderate to severe central canal stenosis, moderate to severe bilateral foraminal narrowing, and left C6 radiculopathy. Surgery was apparently discussed as a possibility, but he was treated with medication and a steroid injection. In 2012, the employee began working for Flynn Dalco Roofing, the employer.

In December 2014, the employee was involved in a motor vehicle incident and was seen at an emergency room, where he reported neck pain but no new or worsening pain. On December 8, 2014, the employee was treated at Regions Hospital for neck pain radiating into his right arm. His history of cervical stenosis was noted and the employee was treated with steroid medication. On December 20, the employee was seen at urgent care and prescribed medication. Physical therapy was also discussed. On December 22, the employee reported no improvement and demonstrated decreased range of motion in his neck due to pain. An MRI scan at the time indicated progressive degenerative changes, moderate central canal stenosis at C4-7, moderately severe bilateral foraminal stenosis at C5-6, and severe bilateral foraminal stenosis at C6-7. There are no medical records indicating the employee had additional cervical spine treatment until January 2016.

In January 2016, the employee began working for the employer at a job site in Brookings, South Dakota. That job did not require any demolition or tear-down work, only installation. On January 16, the employee sought treatment with a chiropractor for right-sided neck and upper back pain radiating down his right arm with constant numbness and tingling. On January 25, the employee sought treatment at the emergency department at Brookings Health System for severe right-sided neck pain radiating to the right shoulder and arm. He did not attribute his symptoms to any specific incident and gave a history of cervical stenosis. He left work on February 6, 2016, because he could do no longer do his work.

On February 8, 2016, the employee began treating at Midwest Spine and Brain for his cervical spine condition. An x-ray indicated anterior bone spurring at C5-6 and C6-7, and he was treated with a steroid injection. An MRI scan indicated severe degenerative disc disease and central spinal canal stenosis at C4-7, severe bilateral foraminal stenosis, and central disc protrusion at C4-5. Dr. David Chang recommended a three-level cervical decompression and fusion surgery at C4-7, which was performed on April 19, 2016. The employee had some relief but continued to have neck pain. Dr. Chang recommended a cervical spinal cord stimulator and referred the employee for a second opinion. Dr. Stefano Sinicropi assessed residual nerve impingement and agreed that a spinal cord stimulator should be considered.

The employee filed a claim petition for a cervical spine Gillette injury on May 12, 2016, claiming temporary total disability benefits, 15-percent permanent partial disability benefits, and medical expenses. The employer and insurer denied that the employee’s cervical spine condition was related to his work activities.

On August 30, 2016, the employee underwent an independent medical examination with Dr. William Simonet, who opined that the employee had not sustained a specific or Gillette injury to his cervical spine on or about January 25, 2016. He noted that the employee does not have a history of repetitive injuries. He also opined that the substantial contributing cause of the employee’s cervical spine condition was his congenitally narrowed cervical spine canal and his degenerative disc disease, accelerated by smoking. Dr. Simonet concluded that the employee’s work activity was not a substantial contributing factor causing, aggravating, or accelerating his ultimate cervical degenerative disease condition. In addition, he opined that the employee did not require work restrictions or any additional medical care or treatment, and had not sustained any permanency.

In a February 2, 2017, report, Dr. Chang opined that the employee’s job activities as a roofer resulted in a cervical spine Gillette injury culminating on January 25, 2016, which aggravated the employee’s pre-existing cervical condition and resulted in a 15-percent permanent partial disability rating. He noted that the employee had treated for neck pain in 2010 and that his work as a roofer required significant lifting, climbing ladders with heavy weights on his shoulders, repetitive use of his arms, and pushing very heavy carts.

Dr. Simonet wrote an additional report dated March 22, 2017, stating that he had reviewed the employee’s imaging scans from 2010, 2014, and 2016, as well as Dr. Chang’s report. He stated that the scans indicated mild progression expected of age-appropriate changes and that the employee’s condition was the naturally occurring progression of the employee’s degenerative disc disease.

A hearing was held on March 2 and May 26, 2017. At the hearing, the employee described the job duties he performed for the employer. The employer and insurer objected to Dr. Chang’s report as lacking foundation. The compensation judge found that Dr. Chang’s opinion was based on adequate foundation and was more persuasive than Dr. Simonet’s opinion. Relying on that opinion, the compensation judge found that the employee had sustained a cervical spine Gillette injury and awarded temporary total disability benefits, 15-percent permanent partial disability, and medical expenses. The employer and insurer appeal.

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). 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, 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).

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).

The compensation judge found that the employee had sustained a cervical spine Gillette injury culminating on or about January 25, 2016, in the nature of a permanent aggravation of the employee’s pre-existing cervical condition.

To establish a Gillette injury, an employee must “prove a causal connection between [his or] her ordinary work and ensuing disability.” Steffen v. Target Stores, 517 N.W.2d 579, 581, 50 W.C.D. 464, 467 (Minn. 1994); see also Carlson v. Flour City Brush Co., 305 N.W.2d 347, 350, 33 W.C.D. 594, 598 (Minn. 1981) (a Gillette injury from repeated trauma results in a compensable injury when the cumulative effect is sufficiently serious to disable an employee from further work). While evidence of specific work activities causing specific symptoms leading to disability may be helpful, whether an employee has sustained a Gillette injury “primarily depends on medical evidence.” Steffen, 517 N.W.2d at 581, 50 W.C.D. at 467.

The employer and insurer argue that the judge erred by relying on Dr. Chang’s opinion. A compensation judge’s choice among conflicting expert opinions is upheld unless the opinion lacked adequate factual foundation. Nord v. City of Cook, 360 N.W.2d 337, 342-43, 37 W.C.D. 364, 372-73 (Minn. 1985). An expert opinion lacks adequate foundation when it does not include the facts and/or data upon which the expert relied in forming the opinion, Steffen, 517 N.W.2d at 581, 50 W.C.D. at 467, the basis for the opinion is not explained, Welton v. Fireside Foster Inn, 426 N.W.2d 883, 887, 41 W.C.D. 109, 115 (Minn. 1988), or the facts assumed by the expert are not supported by the evidence. Schuette v. City of Hutchinson, 843 N.W.2d 233, 237, 74 W.C.D. 169, 173-74 (Minn. 2014). The opinion need only be based on sufficient facts to form a “reasonable opinion not based on speculation or conjecture.” Thyer v. Dallas Stars Hockey Club, 60 W.C.D. 507, 515 (W.C.C.A. 2000) (citing State Farm Fire & Cas. Co. v. Wicka, 474 N.W.2d 324 (Minn. 1991)), summarily aff’d (Minn. Nov. 16, 2000). A compensation judge has considerable discretion in determining the adequacy of foundation for an expert opinion, which is subject to review for abuse of discretion by this court. See Reinhardt v. Colton, 337 N.W.2d 88, 92 n.1 (Minn. 1983); see also Gross v. Victoria Station Farms, Inc., 578 N.W.2d 757, 760-61 (Minn. 1998).

The employer and insurer argue that Dr. Chang’s opinion does not meet the foundation requirements and should not be considered in determining whether the employee had sustained a Gillette injury. The employer and insurer first assert that Dr. Chang’s opinion did not include adequate facts and/or data upon which he relied in forming the opinion because he did not review the employee’s imaging scans from 2010 and 2014. They contend that Dr. Chang did not explain the basis of his opinion regarding causation given the employee’s pre-existing condition and also claim that the employee’s MRI scan in February 2016 had the same findings as the employee’s previous scans. They further argue that Dr. Chang did not understand the employee’s actual work activities at the relevant time. In addition, the employer and insurer claim that Dr. Chang’s opinion assumed facts not supported by the evidence since he relied on an assertion, not made by the employee until June 2016, that he had been swinging a heavy hammer before he was injured and that he was asymptomatic except for an episode of pain in 2010.

In 2016, Dr. Chang was aware of the employee’s 2010 diagnosis of cervical spine stenosis when he noted that the employee’s symptoms at that time were in his left arm, while his current symptoms were in his right arm. He was also aware of the employee’s work duties over many years as a roofer as listed in his narrative report. Dr. Simonet admitted that the employee’s findings on his imaging scans indicated mild progressive changes. While the employee’s use of a hammer was not mentioned in the employee’s medical record until June 2016, the employee testified at the hearing that he had been using a hammer at the Brookings job as part of the installation work. The compensation judge did not specifically address the employee’s use of a hammer, but we note that the judge could have reasonably concluded that use of a hammer was likely during installation of a new roof. The employer and insurer are correct that Dr. Chang did not mention the employee’s cervical spine treatment in 2014. This omission fails to establish that the report as a whole lacks adequate foundation. See Wenner v. Gulf Oil Corp., 264 N.W.2d 374, 381 (Minn. 1978). The employer and insurer’s arguments go to the weight to be given the opinion rather than to the foundation for the doctor’s opinion. Again, the compensation judge is given discretion to assess the weight and sufficiency of a medical expert’s opinion and to resolve any conflicting medical opinions. See Nord, 360 N.W.2d at 342-43, 37 W.C.D. at 372-73; see also Ruether v. State, 455 N.W.2d 475, 477-78, 42 W.C.D. 1118, 1121-22 (Minn. 1990). The compensation judge did not err by relying on Dr. Chang’s opinion.

The employer and insurer also claim that the employee’s testimony, which described his work duties before he developed symptoms in 2016, was not relevant to his claim and that his testimony was discredited by the medical evidence and the testimony of his supervisor. Their theory is that because the employee did not develop symptoms until after the Brookings job, where he only performed installation work, any reference to work activities involved in tear-down work was not relevant. The employee’s supervisor testified that the job in Brookings only involved installation work and involved a lighter material than the employee described using. The judge, however, found the employee to be credible as to the physically demanding nature of his work activities since he began working for the employer. Contrary to the employer and insurer’s assertion, the employee’s testimony regarding his heavy work activities during tear-down work and installations before he had symptoms is relevant to his claim of a Gillette injury because Gillette injuries are based on the cumulative effect of repeated trauma which is not limited to a specific time frame before symptoms occur. The compensation judge should also consider the nature and extent of the employee’s work duties in determining causation of a Gillette injury. “Ultimately, it is the responsibility of the compensation judge to weigh all of the evidence in the case to decide whether the work activities caused the disability.” Aderman v. Care Free Living Retirement Home, slip op. at 6 (W.C.C.A. Apr. 27, 2000).

The employer and insurer also point out that the employee did not connect his symptoms to his work activities in January 2016 when he was treated, but related it to his pre-existing cervical stenosis. The employee was not claiming a specific injury which occurred during the Brookings job, but a Gillette injury based on the cumulative effect of repeated trauma sufficiently serious to disable the employee from further work. See Carlson, 305 N.W.2d at 350, 33 W.C.D. at 598. The judge noted that the employee admitted that he did not attribute his increased cervical pain to a specific incident, and emphasized that it was clear that the employee was not aware that he may have suffered a Gillette-type injury. Further, the employee is not required to show specific work activities caused specific symptoms leading to disability in order to prove a Gillette injury. Steffen, 517 N.W.2d at 581, 50 W.C.D. at 467. The compensation judge acknowledged that the employee had pre-existing cervical stenosis, but found that the employee was able to perform extremely heavy duty full-time work as a roofer with that condition, and without restrictions, until January 2016.

Substantial evidence supports the compensation judge’s finding that the employee sustained a cervical spine Gillette injury culminating on or about January 25, 2016, and we affirm.