The employer and insurer appeal from the compensation judge’s finding that the employee was temporarily totally disabled between October 5, 2008, and the hearing on May 28, 2010, as a result of his work injury.  We affirm, in part, and modify, in part.

Mr. John Onyemekeihia, the employee, sustained an admitted back injury on April 24, 2008, while employed as a certified nursing assistant [CNA] for Guardian Angels Health & Rehabilitation Center, the employer.  He noted back pain after transferring a resident from a wheelchair to a bed.  The employee testified that he completed his work shift after his injury, performing light-duty work.  He sought medical treatment the next day at the Duluth Clinic - Virginia, reporting upper and lower back pain.  Dr. Showkat Khan, who examined the employee, detected tenderness and muscle spasm involving the paravertebral muscles in the thoracic and lumbar areas.  Dr. Khan diagnosed a thoracic and lumbar strain, and restricted the employee to sedentary work.

The employee also sought chiropractic treatment from Dr. Brian Plesha that same day.  He reported to Dr. Plesha that he experienced back pain after lifting a resident from her wheelchair to a bed, and that the pain had worsened since its onset.  Dr. Plesha provided chiropractic treatments and restricted the employee from employment through May 8, 2008.  Thereafter, Dr. Plesha released the employee to return to work and imposed restrictions of no repetitive bending, lifting, or twisting, and a lifting limit of 30-35 pounds.

At the time of his injury, the employee was regularly employed at two jobs, with the employer, Guardian Angels, and also with Northland Rehabilitation Service; he earned a combined stipulated weekly wage of $508.98.  Even though he was restricted from his job with the employer through May 8, 2008, the employee continued to work at his second job, as his work there did not involve lifting.

Within approximately two weeks of his injury, the employee briefly returned to work for the employer, but soon resigned to move to Duluth, Minnesota, where he had sought employment prior to his injury.  He eventually was offered a position as a CNA at a nursing home owned by St. Louis County, the Chris Jensen Nursing Home.  On June 5, 2008, as part of the application process for that position, the employee underwent a pre-employment physical examination and screening at Center Therapy.  During that examination, which required him to perform certain physical activities and exercises, the employee denied that he had experienced any earlier low back problems or had undergone treatment for his low back.^[1]

The employee began working for the nursing home on June 26, 2008.  The employee was discharged from this position within his probationary period.  There is conflicting information in the record as to the reason for his discharge, and whether it was related to the employee’s physical capabilities or due to other reasons.

The employee continued his chiropractic treatment with Dr. Plesha in Virginia, Minnesota, through June 18, 2008.  In late July, he consulted Miller Hill Chiropractic where he reported worsening low back and upper back pain from his injury in April.

The employee next worked at a temporary nursing assistant position with Interim Temporary Services, and later worked for HealthStar Staffing.  On August 19, the employee sought treatment at the Duluth Clinic, reporting low back pain radiating into his left leg.  Dr. Kenji Sudoh, orthopedist, referred the employee for an MRI scan, which was performed on August 19.  The scan detected disc extrusions at the L2-3 and L3-4 levels as well as a L2-3 left anterolateral dural sac deformity which Dr. Sudoh described as “possible nerve trapping that would be consistent with [the employee’s] symptoms.”  Dr. Sudoh diagnosed radiculopathy of the left leg and symptomatic disc disease.

Dr. Sudoh referred the employee to Dr. Frederick Harris for a neurosurgical evaluation.  Dr. Harris examined the employee on August 26, 2008, and recommended immediate surgery on the basis that the employee’s significant weakness in his left lower extremity could result in permanent weakness and development of a foot drop.  Dr. Harris restricted the employee from work pending surgery.

On August 29, 2008, the employee underwent surgery by Dr. Harris, consisting of L2-3 and L3-4 hemilaminectomies, medial facetectomies, foraminotomies, and microdiscectomies.  The employee apparently returned to work at HealthStar Staffing a week after his surgery, admittedly against Dr. Harris’s restrictions, and worked there until October 5, 2008.  He testified that he stopped working at that point on the advice of his former attorney.

The employee received follow-up care at the Duluth Clinic, including a consultation on October 10, 2008, at the Urgent Care center for pain and aching in his hips and upper thighs, and an examination on October 16, 2008, with Dr. Harris.  The employee reported continued low back pain and radiation in the inguinal area, and Dr. Harris noticed swelling in the surgical incision area.  He restricted the employee from work until re-evaluation, and recommended that the employee find work other than as a CNA due to the physical requirements of that type of work.

Between October 2008 and the date of hearing, the employee received medical treatment at the Duluth Clinic, including physical therapy, therapeutic exercises, and use of prescription pain medication.  Dr. Harris examined the employee in mid-January 2009.  At that time, the employee reported improvement in his symptoms but continued low back pain with activities of daily living.  Dr. Harris released the employee to light-duty work with follow-up care to be provided by his primary care physician.

In October 2008, the employee began receiving Minnesota Family Investment Program (MFIP) payments.  He testified that he looked for work following his August 2008 surgery, but that he was unable to find replacement employment.  He also testified that under the terms of the MFIP program he was required to look for work, but if he was unsuccessful in obtaining a job he was asked to perform volunteer work as a condition of receiving MFIP payments.  For example, at times since 2008, he has performed cleaning tasks and has worked in the kitchen at the Arrowhead Economic Opportunity Agency and has served food and cleaned tables at the Union Gospel Mission in Duluth.  The employee has performed this work primarily on a volunteer basis, at the rate of 5 hours per day, 5 days per week, although he was paid wages for approximately one month in mid-2009 while working at the Union Gospel Mission.

On February 16, 2009, Dr. Nolan Segal examined the employee at the request of the employer and insurer.  In his report issued March 27, 2009, Dr. Segal concluded that the employee had sustained a low back strain on April 24, 2008, which was superimposed on his preexisting degenerative disc disease.  Dr. Segal concluded that the employee’s disc herniations, detected on MRI in August 2008, were unrelated to his work injury in 2008 and instead were due to an idiopathic problem.  Dr. Segal concluded that the surgery performed by Dr. Harris, and the restrictions he later assigned, were reasonable and necessary, but were unrelated to the employee’s work injury.  Dr. Segal concluded that the employee had reached maximum medical improvement [MMI] as of the date of his examination.  He recommended an active home exercise program, including low impact general conditioning and stretching exercises, and the use of a TENS for a period of eight weeks.  Dr. Segal concluded, however, that such treatment recommendations were not related to the employee’s work injury.

The employee continued receiving follow-up care at the Duluth Clinic, including treatment for his low back pain and his reported numbness in his left leg and left foot.  Dr. Okechuku Iwu, in the Internal Medicine department of the Duluth Clinic, provided follow-up care for the employee starting in early 2009.  On August 12, 2009, in response to a request for a medical opinion from the Minnesota Department of Human Services, Dr. Iwu advised that the employee would be able to perform limited employment of 20 hours per week, commencing October 20, 2009.  At an examination on October 31, 2009, the employee complained to Dr. Iwu of low back pain and some tingling in both feet.  Dr. Iwu’s chart note states that he found the employee’s low back pain to be “problematic enough to prevent him from returning to his past vocation but stable enough that in the not too-distant future, he could undertake sedentary pursuits, at least on a part-time basis.”

Dr. Iwu later referred the employee to Dr. Mathew Eckman at the Duluth Clinic’s physical medicine department.  Dr. Eckman examined the employee on May 20, 2010, and recommended a trial of outpatient physical therapy, and if such was not helpful, perhaps facet injections.  He released the employee to work on a light-duty basis.

The employee filed a claim petition, seeking temporary total disability benefits from April 24, 2008 through May 8, 2008, and ongoing benefits from October 5, 2008.  The employer and insurer denied liability for the claimed benefits, contending that the employee’s injury was temporary in nature.

The employee’s claim was addressed at a hearing held on May 28, 2010.  In his findings and order issued following that hearing, the compensation judge concluded that the employee’s work injury of April 24, 2008, represented a substantial contributing factor in his need for low back surgery in 2008, work restrictions, and additional medical treatment.  The judge also concluded that the employee had not yet reached maximum medical improvement.  He awarded the employee’s claim for temporary total disability benefits for the period of time from October 8, 2008, through the date of hearing, to continue as warranted.  He based that award on the employee’s continued symptoms and his physical work restrictions, and that the employee had conducted a reasonable job search since his injury.

The compensation judge denied the employee’s claim for temporary total disability between April 24, 2008, and May 8, 2008, on the basis that the employee had continued working part time at his second job during that period of time.  The compensation judge allowed the employee to preserve a future claim for temporary partial disability benefits during that period of time.^[2]

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 (2008).  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).

The compensation judge relied on the records of Dr. Frederick Harris, the employee’s treating surgeon, and rejected the opinions of the independent medical examiner, Dr. Nolan Segal, when rendering his decision.  The employer and insurer appeal, contending that the compensation judge’s findings are erroneous and not supported by substantial evidence.  The employer and insurer argue that the record contains no medical opinion, from the employee’s surgeon or any treating physician, attesting to the causal relationship between the employee’s April 2008 work injury and his subsequent surgery and disability from work.  They argue that because the employee failed to present a medical opinion expressly supporting his position, the compensation judge erred in his decision as to causation.

The employer and insurer argue that the compensation judge’s decision “cannot be justified by the evidence in the record,” either by medical opinion or by other evidence.  They point to the following factors: (1) the employee’s release to work in May 2008, (2) his continued work and physical activities for multiple employers thereafter, (3) his ability to pass a pre-employment physical examination in June 2008, (4) his representations to other employers concerning his physical capabilities for performing his jobs and his physical activities at those jobs; and (5) personal nonwork-related reasons for the termination of his employment at his jobs subsequent to his employment with the employer.  In support of their contention that the employee failed to produce an express medical opinion that his disability was caused by his work injury, the employer and insurer argue that Dr. Segal’s opinion, which was based upon a complete review of the employee’s medical history, was “the only credible medical opinion” in the record, and that he issued a well-reasoned report “directly addressing the issues in this case.”  The employer and insurer cite to this court’s language in Satrum v. City of Minneapolis Public Works, No. WC09-4982 (W.C.C.A. Mar. 9, 2010) to the effect that “the finder of fact in a workers’ compensation proceeding is not free to disregard unopposed medical testimony because such testimony concerns issues not within the realm of knowledge of the fact finder.”  We are not persuaded.

Causation is a question of fact for the compensation judge to determine.  Felton v. Anton Chevrolet, 513 N.W.2d 457, 50 W.C.D. 181 (Minn. 1994); Hendricks v. Roof Depot, slip op. (W.C.C.A. Dec. 11, 2002).  This court, however, has recognized that even though unopposed expert medical testimony cannot be disregarded, such testimony is not necessarily conclusive upon a trier of fact.  Palmer v. ELO Engineering, slip op. (W.C.C.A. June 28, 2005), citing Tuomela v. Reserve Mining Co., 299 Minn. 203, 204, 216 N.W.2d 638, 639, 27 W.C.D. 312, 313 (1974).  While a medical opinion as to causation is desirable in making a case to a compensation judge, it is not always essential where there is other reliable evidence on the issue.  See, e.g., Bender v. Dongo Tool Co., 509 N.W.2d 366, 367, 49 W.C.D. 511, 513 (Minn. 1993) (in the commoner afflictions, a finding of fact on causation will not be disturbed on appeal even without medical testimony).  Furthermore, although the medical record in this case does not contain an express causation opinion from Dr. Harris supporting the employee’s claim, it is apparent that he and other treating doctors had accepted that the employee’s work injury had caused his condition.  See Sutherland v. Metropolitan Council Transit Operations, slip op. (W.C.C.A. Oct. 14, 1997) (causation opinion not essential where there is other reliable evidence on the issue of causation).

Throughout his findings, the compensation judge cited to various medical records documenting treatment the employee had undergone since his injury on April 24, 2008, and the physical findings on examination, treatment recommendations, and work restrictions assigned by Dr. Harris.  The record also contains a causation opinion from Dr. Plesha, with whom the employee treated between April 25 and June 18, 2008.  In a letter dated March 19, 2010, Dr. Plesha concluded that there were “clinical indications that could have suggested lumbar disc involvement relative to his 4-24-08 work injury,” and that “there is no doubt” that the clinical findings on the lumbar MRI scan “could have originated from his 4-24-08 work injury and supported by the documentation at this office.”  Citing to Lagergren v. CenterPoint Energy, 68 W.C.D. 454 (W.C.C.A., July 15, 2008), the employer and insurer argue that Dr. Plesha’s opinion, that there “could” be a causal relationship to the employee’s work injury, falls short of the standard required for medical testimony. See Holmlund v. Standard Constr. Co., 307 Minn. 383, 389, 240 N.W.2d 521, 525, 28 W.C.D. 317, 324 (1976) (“To sustain a finding of causal relation it is not enough that there is medical testimony that the injury might have caused the subsequent condition or could have caused that condition but there must be medical testimony that the injury did cause that condition.”)(emphasis in original).  However, to establish causation, “a medical opinion does not have to express absolute certainty . . . and it is sufficient if it is probably true.”  Pommeranz v. State, Dep't of Public Welfare, 261 N.W.2d 90, 91, 30 W.C.D. 174, 177 (Minn. 1977).  As this court has explained,

As a reviewing court, we are directed to affirm a compensation judge’s decision if it is supported by substantial evidence.  Hengemuhle, 358 N.W.2d at 59, 37 W.C.D. at 239.  The compensation judge relied on the records generated by Dr. Harris, and found that:

The employer and insurer also appeal from the compensation judge’s finding that the employee has not yet reached MMI.  They argue that there is no medical or factual basis for the compensation judge’s conclusions, that Dr. Segal is the only doctor to address the issue of MMI, that no treating physician has rendered an opinion concerning MMI, nor has any doctor provided an opinion as to what, if any, improvement can be expected at this time.

Maximum medical improvement is defined as “the date after which no further significant recovery from or significant lasting improvement to a personal injury can reasonably be anticipated, based upon reasonable medical probability.”  Minn. Stat. § 176.011, subd. 25; see also Minn. R. 5221.0410(3).  Whether MMI has been reached is a question of ultimate fact for the compensation judge to decide.  Hammer v. Mark Hagen Plumbing & Heating, 435 N.W.2d 525, 528-29, 41 W.C.D. 634, 639 (Minn. 1989).  The burden of proving maximum medical improvement is normally on the employer and insurer.  Paoli v. Rainbow Foods, No. WC05-304 (W.C.C.A. July 28, 2006); Burns v. Firestone Tire & Rubber, slip op. (W.C.C.A. June 29, 1993).

In this case, the compensation judge acknowledged that the sole opinion in the record on the issue of MMI is that of Dr. Segal, but that he specifically rejected that opinion.  Instead, upon review of the record, the judge referred to the additional medical treatment recommended by Dr. Eckman shortly before the hearing, including physical therapy and possibly facet injection.  At Finding No. 21, the compensation judge concluded that “contrary to Dr. Segal’s opinion the employee was not at MMI as of Dr. Segal’s examination on February 16, 2009 and his subsequent report of March 27, 2009.”  He also concluded that

The employer and insurer also argue that the compensation judge erroneously awarded temporary total disability benefits from January 13, 2009, when the employee was released to return to work, through February 10, 2010.  They contend that the employee did not present any evidence of a job search during that period of time.

The Minnesota workers’ compensation statute provides for temporary total disability benefits when, as a result of a work-related injury, an employee

In addition, “a diligent job search remains relevant in determining total disability,” and an “injured employee proves total disability by showing that work the employee is capable of doing is unavailable, and unavailability is shown by a diligent job search to no avail.”  Redgate v. Sroga's Standard Serv., 421 N.W.2d 729, 733, 40 W.C.D. 948, 954 (Minn. 1988).  “A diligent job search is one that is reasonable under all the facts and circumstances peculiar to the case, and whether or not an employee has performed a diligent job search is a factual question for resolution by the compensation judge.”  Kunferman v. Ford Motor Co., 56 W.C.D. 163, 167 (W.C.C.A. 1996), summarily aff’d (Minn. Feb. 20, 1997).  “Whether an injured employee makes a reasonably diligent search for suitable employment is a question of fact which must be upheld unless manifestly contrary to the evidence.”  Hanmer v. Wes Barrette Masonry, 403 N.W.2d 839, 841, 39 W.C.D. 758, 761 (Minn. 1987).  The issue before this court is whether substantial evidence supports the compensation judge’s finding that the employee conducted an adequate job search between January 13, 2009, and February 10, 2010.^[3]

One factor for consideration is the scope of rehabilitation assistance provided by the employer and insurer.  Although the employee in this case was not provided any rehabilitation assistance after his injury, presumably in part because he initially resigned from his position and commenced work for another employer, the lack of rehabilitation services did not eliminate the employee’s responsibility to make a diligent search within his limitations.  See Priglmeier v. Steller Concrete & Masonry, 65 W.C.D. 384, 400 (W.C.C.A. 2005).

The employee submitted records of jobs for which he applied from January through March 2010, including copies of application forms and a list of employers.  He testified that he had searched for work before 2010, although the record does not contain documentation of that earlier job search.  The employee also testified that under the terms of the MFIP program he was required to look for work in order to receive financial assistance, but if he was unsuccessful in obtaining a job he was asked to perform volunteer work for a community program.  He testified that he continued to work as a volunteer in 2009 and 2010, and continued his volunteer work at the time of the hearing.  (See Employee Ex. H.)

The compensation judge concluded that the “employee’s work restrictions including his off-work status since October 5, 2008 have been reasonable and related in substantial part to [his] work injury of April 24, 2008.”  He also concluded that

The compensation judge outlined the factors that led to his conclusion that the employee’s job search was sufficient to support his claim for temporary disability benefits.  He referred to restrictions assigned by the employee’s treating physicians since 2008 and their recommendations that the employee change vocations due to the physical labor required for nursing assistant work.  For example, in October 2008, Dr. Harris recommended that the employee find work other than as a CNA as that work involved too much physical labor, and he released the employee to light duty work in January 2009.  In October 2009, Dr. Iwu advised that the employee’s low back pain was “problematic enough to prevent him from returning to his past vocation, but stable enough that in the not-too-distant future, he could undertake sedentary pursuits, at least on a part-time basis.”  In addition, Dr. Eckman recommended light duty work after examining the employee in May 2010.

The evidence in the record, including medical records, job search records and the employee’s testimony, supports the compensation judge’s findings that the employee’s work injury was a substantial contributing cause of his continued work restrictions and that the employee conducted a diligent job search sufficient to support his entitlement to the awarded temporary total disability benefits.  Accordingly, we affirm, with modification.  We modify the compensation judge’s award for the approximately one month period in mid-2009 when the employee was paid wages for his otherwise volunteer work at the Union Gospel Mission.  For that period of time, payment of benefits is to be limited to temporary partial disability based on the wages received by the employee.