The employer and insurer appeal from the compensation judge’s findings that the employee’s July 23, 2007, personal injury resulted in a permanent aggravation of a preexisting spondylolisthesis and substantially contributed to the development of a herniated disc at L5-S1, and was a substantial contributing cause of the employee’s need for medical treatment, including fusion surgery.  The employer and insurer also appeal from the compensation judge’s award of temporary partial disability benefits from September 1, 2009, through the date of hearing.  We affirm in part and reverse in part.

Jared Anderson, the employee, sustained a personal injury to his neck, left shoulder, right index finger, and low back on July 23, 2007, in the course of his employment with Wherley Moving & Storage, Inc., the employer, then insured by Vanliner Insurance Company.  The employer and insurer admitted the injury, but disputed the nature and extent of the employee’s low back condition.

The injury occurred when a moving van traveling at highway speed, in which the employee was a passenger, rear-ended a slow-moving farm tractor on Highway 2, just east of Devils Lake, North Dakota.  The employee was taken by ambulance to Mercy Hospital in Devils Lake.  According to the ambulance report, the employee’s seatbelt failed and he was thrown forward, rotating to his left, striking the windshield with his left arm.  The EMTs noted a large number of small lacerations in the employee’s left forearm and hand and in the right hand region.  The employee complained of pain in his left arm and in his lower back.

The employee was examined by Kevin Jacobson, CNP,^[1] at the Mercy Hospital emergency room.  The employee reported his seatbelt failed causing him to go forward striking the windshield with the left side of his body.  The employee mentioned he had had intermittent back pain for some time, but nothing significant.  Mr. Jacobson’s assessment was multiple abrasions and contusions, superficial lacerations, mild neck pain, and left flank lateral rib wall-chest pain.  Mr. Jacobson advised the employee he should expect aches and pains with gradual worsening and then gradual improvement, and advised him to seek immediate evaluation if he experienced a sudden sharp onset of pain or pain that gradually worsened and did not seem to dissipate.  The discharge instructions note multiple lacerations left arm and forearm, right knuckle abrasions, and left low back pain.

The employee completed an Accident Report/First Report of Injury on July 25, 2007, in which he reported lacerations and bruising of his left arm, bruising of his shoulder and left lower ribs, a sore neck, and that his low back was very sore.  The employer and insurer admitted the injury and commenced payment of temporary total disability benefits.

The employee was seen by Dr. Paul Fleissner on August 7, 2007, for an occupational medicine consultation.  The employee complained of neck and upper back pain, as well as discomfort in his left shoulder.  Dr. Fleissner noted no low back pain and no numbness or tingling in the lower extremities.  The doctor reviewed the employee’s medical history, including previous chiropractic care, stating it was “unremarkable.”  (Ex. C4.)  On examination, the doctor noted, among other things, a small amount of tenderness across the lumbosacral junction in the low back.  Dr. Fleissner referred the employee for physical therapy, and released the employee to return to light-duty work with no lifting over 20 pounds.

The employee received three months of physical therapy beginning August 9, 2007, for a low back strain and left shoulder strain.  He reported sharp pain in the back, but no radicular symptoms, with difficulty bending over, standing, or sitting too long.  The therapist observed the employee had to shift positions frequently during the initial evaluation.

In early August 2007, the insurer appointed Ted Greshik, a qualified rehabilitation counselor (QRC), to provide rehabilitation services to the employee.  In his progress report of August 17, 2007, Mr. Greshik noted the employee’s job with the employer required an extensive amount of heavy lifting and carrying, and the employer could not provide any transitional modified or alternative work for the employee within his restrictions.  Mr. Greshik further noted the employee was pursuing a degree as a surgical technician at Northland Community College and would be returning to school on August 27, 2007.

The employee continued to treat with Dr. Fleissner for his low back injury and and left shoulder sprain.  On August 21, 2007, the employee complained of sharp pain in the low back.  Dr. Fleissner assessed a “reactivation of chronic lumbar back pain” and continued the employee’s work restrictions, additionally limiting bending, stooping and twisting with no overtime work.  The employee experienced steady improvement in his left shoulder, but reported gradually worsening low back pain.  On October 26, 2007, noting the employee was not making much progress, Dr. Fleissner ordered a lumbar spine MRI scan.  The scan, performed on November 16, 2007, showed disc dehydration at L5-S1, mild anterior subluxation of L5 on S1, and bilateral spondylolysis at the L5 level.  When seen by Dr. Fleissner on December 7, 2007, the employee reported persistent low back pain with some discomfort into the left hip, sometimes shooting into the upper left buttock.  Dr. Fleissner noted the employee had a long history of lumbar back pain, and stated, “[t]his may represent basically his baseline status and is probably preexisting.”  The doctor released the employee to light-medium work, bending repetitively only rarely, other functions at least occasionally.  (Ex. C4.)

In his January 18, 2008, progress report, Mr. Greshik noted the employee had ongoing low back symptoms.  Based on findings of spondylolisthesis at L5-S1 along with continuing and increasing soreness and discomfort in the low back, the employee requested a neurosurgical consultation.  Work hardening had also been recommended and was initiated, with a functional capacities evaluation (FCE) to be completed at the conclusion of the program.

The FCE was conducted on April 28, 2008.  The employee reported low back pain throughout the testing, with limited bending, sitting, standing, and walking work tolerances.  The therapist stated the employee would be physically unable to return to his previous job.  She further expressed concerns about the employee’s ability to do surgical technician work and recommended he explore other job options.  The employee was given medium-work restrictions, full-time, with limited bending, sitting, standing, walking, and overhead work.  The employee continued to attend classes at Northland Community College, on a part-time basis, but, in the fall of 2008, switched to a business degree program.

The employee was examined by Dr. Sunny Kim, a neurosurgeon, on June 18, 2008.  The employee reported having low back pain immediately following the July 23, 2007, accident which gradually worsened, complaining, at the time of the examination, of low back pain with radiation into the posterior right thigh.  Dr. Kim read the November 2007 MRI scan as showing spondylolisthesis at L5 on S1 with a right-sided herniated disc and stenosis with some right L5 nerve root impingement.  Dr. Kim stated the employee would most likely require a lumbar fusion at least at L5-S1 and possibly including L4-L5.  The doctor released the employee to work, restricting lifting to no more than 30 pounds.

The employee was examined by Dr. Thomas Nelson, an orthopedic surgeon, on August 11, 2008, at the request of the employer and insurer.  Dr. Nelson read the November 2007 MRI scan as showing L5 on S1 spondylolisthesis with some moderate narrowing of the foramen bilaterally, as well as a herniated disc on the right at L5-S1 causing bilateral foraminal stenosis.  The employee reported constant low back pain, but no leg pain except in the buttock on the right side.  Dr. Nelson opined the employee sustained, at most, a lumbar strain as a result of the July 23, 2007, accident, and opined that maximum medical improvement (MMI) had been reached for the work-related injury.  The doctor further opined the employee’s L5-S1 spondylolisthesis was a preexisting condition, not related to the motor vehicle accident.  Dr. Nelson agreed the fusion surgery recommended by Dr. Kim was reasonable to address the spondylolisthesis, but was not, in his opinion, related to the employee’s work injury.

On September 10, 2008, the employer and insurer served a notice of intention to discontinue temporary total disability benefits (NOID) as of September 1, 2008, based on Dr. Nelson’s report, asserting the employee had reached MMI as of August 11, 2008, with no impairments related to the work injury.

On September 18, 2008, QRC Greshik, referencing Dr. Nelson’s report, stated he had “informed Mr. Anderson that I would await any decision by the state so as to identify whether it would be appropriate to provide any further rehabilitation services.”  He later explained that due to the NOID, no further medical services had been authorized.  As the QRC, he stated, he was bound by the medical recommendations of the primary health care provider  and, consequently, he was unable to provide assistance or close out rehabilitation services until such time as a determination was made by the state.  (Ex. D.)

In a report dated March 5, 2009, Dr. Kim stated the employee had a work-related injury on July 23, 2007, causing lumbar pain.  The doctor stated that prior to the injury, the employee had never complained of radicular pain, and that now the employee had radicular pain as a result of L5 nerve root compression due to a herniated disc complicated by his pre-existing spondylolisthesis.  Dr. Kim opined the employee’s pre-existing spondylolisthesis was markedly aggravated, on a permanent basis, as a result of the July 23, 2007, accident.  He further believed the disc herniation at L5-S1 and right L5-S1 foraminal narrowing most likely developed as a result of the work accident.  Dr. Kim continued to recommend a lumbar fusion, stating the surgery was directly referable to the work-related injury.  The doctor restricted the employee to very light duty work, with lifting no more than 10 pounds on an occasional basis.

On August 20, 2009, Mr. Greshik reported the employee would be starting employment on August 29, 2009, in a part-time bartending position [for VenuWorks] at the Alerus Center in Grand Forks, North Dakota.  The employee continued to attend school on a part-time basis.

On September 15, 2009, the employee returned to see Dr. Kim reporting persistent low back pain and bilateral hip and leg pain.  Dr. Kim ordered an updated MRI scan of the lumbar spine that was completed on September 21, 2009.  The scan was read as showing degenerative disc disease, spondylolisthesis, a disc protrusion, and central spinal canal stenosis at L5-S1.  On the basis of the MRI scan, Dr. Kim recommended a single-level fusion at L5-S1.

The employee filed a claim petition in November 2008 seeking wage loss benefits and medical expenses from and after September 1, 2008.  In November 2009, the employee filed a medical request seeking authorization for the fusion surgery recommended by Dr. Kim.  The employer and insurer denied liability for additional benefits.

Following a hearing on January 6, 2010, a compensation judge found (1) the employee sustained a permanent aggravation of his preexisting spondylolisthesis as a result of the July 23, 2007, motor vehicle accident, and the accident substantially contributed to the development of a herniated disc at L5-S1; (2) the July 23, 2007, injury was a substantial contributing cause of the employee’s need for medical treatment from September 1, 2008, through the date of hearing and the employee’s need for fusion surgery; (3) the employee was entitled to temporary total disability benefits from September 1 to September 18, 2008, but was not entitled to temporary total benefits from September 19 through July 23, 2009;^[2] and (4) temporary partial disability benefits were payable from September 1, 2009, to the date of hearing, based on the employee’s part-time bartending employment for VenuWorks of Grand Forks.  The employer and insurer appeal from the judge’s findings on causation and his award of temporary partial disability benefits.

The employer and insurer contend that substantial evidence does not support the compensation judge’s determination that the employee’s July 23, 2007, work injury was a substantial contributing cause of the employee’s current disability and his need for surgery.  The employer and insurer assert Dr. Kim’s opinion, accepted by the compensation judge, lacks adequate foundation.  They argue Dr. Nelson’s opinion, that the employee’s injury resulted in no more than a temporary lumbar strain, is the only medical opinion that is sufficiently founded and substantially supported by the evidence.  We disagree.

The employer and insurer assert Dr. Kim’s records show the employee denied prior back problems.  However, they argue, the employee previously received chiropractic care for back pain, the last time being less than three months before the work injury.  There is no dispute the employee had occasional chiropractic care to the neck and back prior to the injury.  He was seen by a chiropractor twice in 1995, once in 1998, once in 1999, and once in 2001, three times in 2002, and three times in 2003.  He did not seek chiropractic care between April 23, 2003, and May 1, 2007, when he received a single treatment for neck, mid-back, and low back soreness and tightness.

The employee was required to complete a physical examination before beginning work for the employer.  The examination was performed on May 14, 2007.  Although the history notes a prior football injury to the back, the doctor stated no work restrictions were necessary, and the employee was hired to work for Wherley.  The employee’s job as a mover/laborer was physically demanding and required significant amounts of heavy lifting, carrying, and bending.  The employee was able to perform the job without difficulty until the July 2007 injury.

At the time of his initial visit with Dr. Kim, the employee, in a patient history questionnaire, stated he had “not really” had previous spine problems or symptoms, “just go to the chiropractor for check ups.”  (Ex. C7.)  At the hearing, the employee testified he had not had any “medical” care for his low back prior to the accident, but had seen a chiropractor for adjustments.  (T. 30-31.)  The employee’s attorney, in a January 21, 2009, letter to Dr. Kim, reported the employee, in the past, had seen a chiropractor on a “random” basis for minor complaints of low back pain, and had been seen last on May 1, 2007, for some soreness and tightness.  (Ex. C7.)  In his March 5, 2009, letter report, Dr. Kim acknowledged the employee previously had some minor low back pain, but stated the employee denied any significant history of low back pain prior to the injury.

It is the responsibility of the compensation judge to weigh the evidence and to draw inferences therefrom.  Where more than one inference may reasonably be drawn from the evidence the compensation judge’s findings are to be upheld.  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 60, 37 W.C.D. 235, 240 (Minn. 1984).  Where medical expert opinion conflicts, the compensation judge’s resolution of that conflict must be upheld by this court unless the facts assumed by the expert in rendering the opinion are not supported by the evidence.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  The compensation judge found the employee was a credible witness.  The judge clearly reviewed the chiropractic treatment records and the employee’s post-injury treatment records, and addressed the employer and insurer’s argument at hearing, making a specific finding and discussing the evidence in his memorandum.  (Finding 2; Mem. at 6).  The judge concluded the employee had no significant ongoing low back symptoms prior to the July 23, 2007, accident, an inference that reasonably could be drawn from the evidence.  The facts assumed by Dr. Kim are consistent with the facts found by the compensation judge, and are not, therefore, lacking in foundation.

The employer and insurer further contend the employee did not begin treating for his low back until over a month after the accident and that the employee had not reported any radicular symptoms until he began seeing Dr. Kim in June 2008, facts of which Dr. Kim was apparently unaware.  We are not persuaded.  The medical records reflect reports of low back pain immediately following the accident, as testified to by the employee, and noted by Dr. Kim.  On the day of the accident, the employee reported low back pain to the ambulance service EMTs, and the emergency room discharge instructions include a diagnosis of low back pain.  An accident report, completed by the employee on July 25, 2007, states “back is very sore.”  (Ex. B2.)  Although Dr. Fleissner noted no low back pain at the employee’s initial visit on August 7, 2007, the doctor also recorded tenderness across the lumbosacral junction.  At the initial physical therapy evaluation on August 9, 2007, the diagnosis included a low back strain and the employee reported sharp pain in the low back.  On August 21, 2007, the purpose for the visit with Dr. Fleissner was listed as follow-up for lumbar injury.  Dr. Fleissner’s chart notes reflect persistent and worsening low back pain.  An MRI scan in November 2007 confirmed spondylolisthesis and bilateral spondylolysis at L5 with narrowing of the neural foramen.  By December 8, 2007, the employee was reporting sharp low back pain with some discomfort in the left hip and occasional shooting pain to the upper left buttock.  The employee was then referred for a neurological consultation due to persistent and worsening soreness and discomfort related to his low back.  The compensation judge concluded,

While a different result could have been reached, the compensation judge reasonably adopted the opinion of Dr. Kim on the evidence presented in this case.  We, accordingly, affirm the compensation judge’s determination that the July 23, 2007, accident permanently aggravated the employee’s low back condition, and was a contributing cause of the employee’s need for fusion surgery.

The compensation judge awarded temporary partial disability benefits to the employee based on his post-injury earnings as a part-time bartender for VenuWorks from September 1, 2009, through the date of hearing, January 6, 2010.  The employer and insurer maintain the employee’s reduced earnings are attributable solely to his voluntary decision to attend Northland Community College and work part-time only.  They contend the employee failed to establish a causal relationship between his disability and any loss of earning capacity, and is, therefore, not entitled to temporary partial disability benefits.

Temporary partial disability benefits are payable while an employee is working but is “earning less than the employee’s weekly wage at the time of the injury, and the reduced wage the employee is able to earn in the employee’s partially disabled condition is due to the injury.”  Minn. Stat. § 176.101, subd. 2.  The employee has the burden of establishing a work-related physical disability and an actual loss of earning capacity that is causally related to the disability.  Krotzer v. Browning Ferris, 459 N.W.2d 509, 512, 43 W.C.D. 254, 259 (Minn. 1990); Dorn v. A.J. Chromy Constr. Co., 310 Minn. 42, 245 N.W.2d 451, 29 W.C.D. 86 (1976).  When an injured employee is released to full-time work but obtains only part-time work, the employee may be eligible for temporary partial disability benefits if he can show that part-time work is all he is able to obtain as a result of the disability.  See, e.g., DeNardo v. Divine Redeemer Memorial Hosp., 450 N.W.2d 290, 293, 42 W.C.D. 626, 631-32 (Minn. 1990).

The compensation judge concluded the employee’s actual earnings created a presumption of earning capacity and the employer and insurer failed to rebut the presumption.  See, e.g., Roberts v. Motor Cargo, Inc., 258 Minn. 425, 104 N.W.2d 546, 21 W.C.D. 314 (1960).  It is, however, the employee’s reduced ability to earn, as opposed to actual wage loss or actual earnings, that is the material factor in determining entitlement to temporary partial disability benefits.  Einberger v. 3M Co., 41 W.C.D. 727, 736 (W.C.C.A. 1989); see Minn. Stat. § 176.101, subd. 2.  The mere fact of earnings does not establish entitlement to temporary partial benefits; it remains the employee’s burden to show that any diminution in earnings is causally related to the disability.  Krotzer, at 512, 43 W.C.D. at 259; Borchert v. American Spirits Graphics, 582 N.W.2d 214, 215, 58 W.C.D. 316, 318 (Minn. 1998).

At the time of the injury, the employee was working full-time, with some overtime, earning a stipulated weekly wage of $417.56.  Although the employee has had significant light-duty restrictions since the injury, he has been released to return to full-time work.  The employee returned to school during the 2007-2008 school year and continued to attend school until shortly before the hearing.  The employee began looking for work sometime in 2009,^[3] and obtained part-time work with VenuWorks, beginning on August 29, 2009.  The employee was paid $8.50 an hour with variable work hours averaging about 8.5 hours a week.  The employee testified that because of school, he would not be able to work a full 40-hour-week and that he did not look for full-time work.

While a job search is not a legal prerequisite to an award of temporary partial disability benefits, it is evidence that a compensation judge may consider in determining whether an employee’s wage loss, while working part-time, is causally related to the work injury.  Nolan v. Sidal Realty Co., 53 W.C.D. 388 (W.C.C.A. 1995); Hawkins v. University of Minn., No. WC07-192 (W.C.C.A. Apr. 22, 2008).  The employee admitted he did not look for full-time employment.  There was no evidence the employee sought additional hours from VenuWorks, or, after obtaining part-time work, searched, without success, for work with more hours or for a second job.

The employee failed to demonstrate that part-time work was the only work available to him and, consequently, failed to establish his wage loss from September 2009 to January 2010 was causally related to the work injury.  Compare, e.g., Strand v. United States Steel Corp., No. WC06-245 (W.C.C.A. Feb. 28, 2007); Kunferman v. Ford Motor Co., 65 W.C.D. 198 (W.C.C.A. 2004).  We, therefore, reverse the award of temporary partial disability benefits for that period of time.