The employee appeals from the compensation judge’s finding that she failed to prove her work injury was a substantial contributing factor in her need for medical treatment.  We affirm.

Roseannette Simmonds was employed by Roundy’s, Inc., at a Rainbow Foods store on January 2, 2007, when she injured her low back as she was lifting a box of melons to be used in the salad bar.

Ms. Simmonds had a previous work-related low back injury in 2005 for which she received chiropractic care and an award of 3.5 percent permanent partial disability.  Ms. Simmonds had no recollection of that injury and testified she had no symptoms in her low back and no work restrictions at the time of the 2007 injury.  After her injury, Ms. Simmonds began treating with a chiropractor, Dr. Scott Salita.  Dr. Salita diagnosed “acute, post-traumatic, moderate to severe sprain/strain involving the lumbar and pelvic regions.”  He began a program of chiropractic adjustment, initially seeing the employee three times a week.

A lumbar MRI scan was done on January 16, 2007, at the request of Dr. Salita.  It was read as showing mild disc desiccation, and diffuse annular bulging at L3-4, L4-5, and L5-S1 with evidence of a central posterior disc herniation at L4-5 but no evidence of extrusion.

Dr. Salita referred Ms. Simmonds to the Noran Clinic where she saw Dr. Ronald Tarrel on February 5, 2007.  Examination at that time showed “tenderness and muscle spasm with stiffness throughout the lumbar spine region especially on the right.”  Dr. Tarrel’s impression was of “lumbar sprain, likely with aggravation of underlying degenerative disease.”  He recommended continued chiropractic care and an epidural injection at L5-S1.

Ms. Simmonds continued to treat with Dr. Salita, with the frequency of treatment declining to twice weekly in April 2007.  In a letter to the insurer on April 10, 2007, Dr. Salita noted improvement in the employee’s condition, and he recommended an additional 12 weeks of chiropractic care.  At that time, he also released Ms. Simmonds to work on a work-hardening basis with her hours of work set initially at four hours a day with no lifting or carrying over 20 pounds.

The employee testified that when she went back to work at Rainbow Foods she was employed as a “demo lady” handing out samples to customers.  She stated the work was within her restrictions, but she found standing to be difficult.  She requested and received what she referred to as a fatigue mat to make her situation more comfortable.

When Ms. Simmonds returned to Dr. Tarrel in May 2007, there were no findings on examination except for positive straight leg raising on the right.  Dr. Tarrel referred Ms. Simmonds for a neurosurgical consultation and she saw Dr. Michael McCue on June 21, 2007.

Dr. McCue recommended a new MRI, which was done on July 18, 2007.  In a report to Dr. Tarrel, Dr. McCue stated that the “MRI is essentially normal,” and he recommended no surgical intervention.

Dr. Tarrel also referred Ms. Simmonds to Physicians Neck & Back Clinic (PNBC), where she saw Dr. Joseph Wegner on August 23, 2007.  She reported to Dr. Wegner that her back and leg pain were increasing.  On exam, Dr. Wegner found tenderness and limited range of motion, but no muscle spasm.  He diagnosed “mechanical low back pain” and “deconditioning syndrome.”  He prescribed a program of physical rehabilitation which the employee began at PNBC.

In his January 24, 2008, chart notes, Dr. Wegner stated he wanted the employee to complete four more rehabilitation sessions before he discharged her from his care.  He also commented that she might be subject to periodic exacerbations of low back pain.  In his March 13, 2008, chart notes, Dr. Wegner noted Ms. Simmonds had experienced an exacerbation of low back pain, but was still continuing to work.  He restricted the employee from lifting over 35 pounds but allowed her to work eight hours a day.

After her referral to Dr. Wegner, Dr. Tarrel saw Ms. Simmonds one more time in 2007.  On December 21, he stated that she had completed most of the program at PNBC, but still had low back pain, knee pain, a “sense of arm weakness,” and headaches.  On exam, Dr. Tarrel found decreased range-of-motion along the right sacroiliac joint and concluded “this may be a sacroiliac problem.”  He provided an injection of Marcaine into the right sacroiliac joint.

Ms. Simmonds does not have a driver’s license and typically walked the 20 blocks between her house and her job.  On April 26, 2008, as she was crossing a street on her way to work, she was struck by a car running a red light.  She estimated the car was going between 25 and 30 miles an hour when it struck her.  She was thrown onto the hood of the car and was carried for about eight feet before it stopped.  Ms. Simmonds was taken by ambulance to North Memorial Hospital where she complained of left knee pain, neck pain, and low back pain.  She was placed in a knee stabilizer and discharged home with pain medications.

There are no medical records or evidence of any treatment for her low back after this incident until May 21, 2008, when she returned to Dr. Tarrel.  Apparently in the meantime, Ms. Simmonds had consulted with an orthopedist at Minneapolis Orthopaedics for her left knee pain.  She ultimately had total knee replacement surgery to her left knee sometime in early 2010.  When Dr. Tarrel saw her in May 2008, Ms. Simmonds reported an increase in her low back pain as well as “significant neck pain.”  Dr. Tarrel provided a sacroiliac injection that had been previously scheduled, and allowed her to return to Dr. Salita for further treatment.

In her last visit with Dr. Salita before the motor vehicle accident, on April 14, 2008, Ms. Simmonds reported improvement in her symptoms, but stated that she was still experiencing intermittent low back and right leg pain.  Dr. Salita recommended continued massage therapy.  After the motor vehicle accident, Dr. Salita began treating the employee twice a week.  According to his treatment notes, he was treating the cervical, thoracic and lumbar spine with manual manipulation, ultrasound, massage, and mechanical traction.

Ms. Simmonds returned to PNBC one time after the motor vehicle accident.  On May 22, 2008, when she saw Dr. Wegner, he stated that “objectively, she has made good progress” and that her subjective pain in the low back and leg had improved as well.  He discharged her from treatment and recommended home exercises.

Ms. Simmonds only treated with Dr. Tarrel intermittently after the motor vehicle accident.  He saw her seven times after the May 2008 appointment, and his treatment consisted of prescribing Flexeril and tramadol for pain.  Dr. Tarrel had a lumbar MRI done in November 2011 that he read as showing mild to moderate degenerative disc changes that might have progressed since the 2007 MRI.

Dr. Richard Hadley saw the employee on two occasions at the request of the insurer.  In his initial report of January 23, 2009, Dr. Hadley stated that, in his opinion, the employee sustained a lumbar sprain at work in January 2007 that did not aggravate her underlying disc disease.  It was his further opinion that the treatment after the motor vehicle accident was attributable to that incident alone.  After a subsequent evaluation in June 2011, Dr. Hadley issued another report in which he reiterated his previous opinions and also stated that no further treatment for the work injury was needed and that the work injury had resolved by March 2008 when the employee saw Dr. Wegner.

Dr. Salita prepared a report for the employee’s attorney on February 22, 2010, in which he stated that his treatment after the motor vehicle accident was due to the motor vehicle accident for five months, but that after that date, his treatment was necessitated by the 2007 work injury alone.

The employee filed a claim for payment of bills at Dr. Salita’s office and the Noran Clinic bills which were incurred after the motor vehicle accident.  The employee also filed a claim for permanent partial disability of seven percent.  The employee’s claims were heard by Compensation Judge Jeanne Knight on December 13, 2011.  In her findings and order of January 30, 2012, the compensation judge awarded the requested permanent partial disability but denied the employee’s claim for medical expenses, finding that the employee had failed to prove the work injury was a substantial contributing factor in the claimed treatment.  The employee appeals the denial of her medical bill claim.

An employee has the burden of establishing, by a preponderance of the evidence, entitlement to payment of medical expenses.  Adkin v. University Health Care, 405 N.W.2d 231, 39 W.C.D. 898 (Minn. 1987); Odash v. Pepsi, Inc., 66 W.C.D. 336 (W.C.C.A. 2006).  In this case, the compensation judge concluded “the employee has not proved the work injury is a substantial contributing factor in the employee’s need for medical treatment after the motor vehicle accident.”  (Finding 19).

Whether a work injury is a substantial contributing factor in the need for medical treatment is a question of causation and is a question of fact for the compensation judge.  Felton v. Anton Chevrolet, 513 N.W.2d 457, 50 W.C.D. 181 (Minn. 1994).  When a factual determination by a compensation judge is appealed, the question for this court is whether the determination is supported by substantial evidence.  Minn. Stat. § 176.421, subd. 1; Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 37 W.C.D. 235 (Minn. 1989).

In her appeal, the employee argues that the compensation judge’s denial of her claim for medical bills was inconsistent with the award of permanent partial disability for the work injury.  Second, the employee contends that the compensation judge misconstrued the meaning of “substantial” in considering whether the employee’s work injury was a substantial contributing factor.

On the first point, the employee cites to our decision in Peterson v. Kandi Kourts, 45 W.C.D. 528 (W.C.C.A. 1991) as standing for the proposition that it is inconsistent to find ongoing treatment not to be reasonable or necessary when there has been a finding of a permanent injury.  Peterson is not relevant to the present case.  The issue here is not whether, in some cases, chiropractic care is appropriate when there has been a permanent injury.  The issue rather is whether the work injury continues to be a substantial contributing factor in the need for treatment when there has been a subsequent, serious, non-work injury.

On the second point, the employee argues that the compensation judge misunderstood the use of the word “substantial” in reviewing whether the work injury was a substantial contributing factor in the need for treatment.  She states that “substantial” simply means “appreciable” and refers to Roman v. Minneapolis Street Railway Company, 268 Minn. 367, 129 N.W.2d 550, 23 W.C.D. 573 (1964).  It is true that in Roman, the court used the phrase “appreciable or substantial” but we do not find “appreciable” to be any easier to define than “substantial.”  The phrase “substantial contributing factor” is not defined anywhere in case law or statute, and we decline to provide a general definition here.  Whether a work injury is a substantial contributing factor in the need for continuing medical treatment is a factual determination to be made by the compensation judge.  This court, in reviewing this and similar factual determinations, looks to whether there is substantial evidence to support the conclusion reached by the compensation judge.  That is to say, are the findings “in the context of the record as a whole . . . supported by evidence which a reasonable mind would accept as adequate?”  If so, this court is required to affirm that determination.  Hengemuhle 358 N.W.2d at 59, 37 W.C.D. at 239.

In her decision, the compensation judge referred to testimony by the employee.  After the work injury, the employee continued to engage in a number of activities that she was no longer able to do after the motor vehicle accident.  She was no longer able to walk to work. She gave up the gardening and yard care that she used to enjoy.  She limits the amount of cooking, grocery shopping, and house work that she does.  She continues to have flare-ups of her low back pain, but has them more frequently now than she did before the motor vehicle accident.  She now has problems sleeping.  The compensation judge concluded that “while the work injury clearly was some factor in the disability following the car accident, she has failed to prove the work injury was a substantial contributing factor in that disability.”

The employee presented a claim for payment of the bills from Dr. Salita and the Noran Clinic.  Dr. Salita’s bill covered the period from May 21, 2009, through February 25, 2010, and totaled $1,037.34.  The Noran Clinic bill was noted by the compensation judge as being “difficult to determine.”  The itemized statement covered services from May 20, 2008, through November 3, 2011, and showed an “account balance” of $4,343.56, and an “outstanding insurance balance” of $2,255.22.

With regard to the denial of the Noran Clinic bill, we find sufficient support in the evidence for the compensation judge’s conclusion.  The employee’s treatment with Dr. Tarrel changed after the motor vehicle accident.  Before the motor vehicle accident, Dr. Tarrel had prescribed physical therapy and epidural injections to the sacroiliac joint.  After the motor vehicle accident Dr. Tarrel’s treatment consisted of appointments for the purposes of reviewing the employee’s status and prescribing Flexeril and tramadol, medications which had not been prescribed prior to the motor vehicle accident.

On the denial of Dr. Salita’s bill, we find sufficient evidence to support the compensation judge’s decision.  Before the motor vehicle accident, Dr. Salita had been providing minimal care for the work injury and had stated in his April 10, 2007, letter to the insurer that he anticipated treating the work injury only for another 12 weeks. While treatment for the dates covered by the claimed bill involved the lumbar spine, Dr. Salita also treated the cervical and thoracic spine and added additional treatment modalities.  We also note here that the compensation judge found the chiropractic care was not reasonable or necessary because Dr. Salita failed to provide the information necessary to establish that his care was reasonable or necessary.  See, for example, Bordeau v. Green Touch Indus., No. WC06-131 (W.C.C.A. Aug. 31, 2006).

The compensation judge also denied the claim for reimbursement of prescription expense.  According to the exhibit introduced by the employee on this issue at the hearing, most of the prescriptions were written by providers whose records were not in evidence and the other prescriptions were the pain medication prescriptions written by Dr. Tarrel after the motor vehicle accident.  The employee failed to establish that these prescriptions were related to her work injury.

Finding substantial evidence to support the compensation judge’s decision, it is affirmed.