The employee appeals the compensation judge’s findings that the employee’s narcotic medications, MS-Contin and Oxycodone, are not medically reasonable and necessary, and that neither these medications nor the employee’s ibuprofen prescription are causally related to the work injury.  We affirm.

The employee worked for the employer as a bookkeeper.  She sustained an admitted low back injury on February 1, 2001 when she tripped and fell against a filing cabinet, striking her chest and twisting her back as in a sprain-type injury.

The employee was first seen for the work injury by her family practitioner, Dr. David Wilhelm, on February 8, 2001.  He had been one of the employee’s treating physicians before her injury.  She had a known history of degenerative disc disease for several years and was obese.  Subsequent to the work injury, she reported pain in the left leg.  Straight leg raising was negative.  She was initially treated with a steroid pack, but her left sciatica failed to improve.  An MRI of the lumbar spine was recommended.

The MRI scan was performed on March 2, 2001.  It showed chronic multilevel degenerative spondylosis at L3-4 and L4-5, and a moderate left-sided foraminal disc herniation at L5-S1 with nerve root compression.  Posterior disc bulging was present at L2-3 and L3-4 but without nerve root compression.

Dr. Wilhelm referred the employee to the Physicians Neck and Back Clinic, where she was treated by physical therapy and an epidural steroid injection.  When her symptoms failed to improve, she was referred to Dr. Bruce Bartie at St. Croix Orthopedics.  On July 11, 2001, Dr. Bartie diagnosed radiculitis at the L5 nerve associated with compression from the L5-S1 herniation.  He recommended a transforaminal epidural steroid injection.  The injection did not result in improvement and Dr. Bartie recommended decompression surgery.  On September 14, 2001, the employee underwent a laminectomy with left lateral decompression of the L5 nerve root.

Following the surgery, the employee initially reported good results.  At her visit on September 28, 2001, two weeks post-surgery, Dr. Bartie released her to return to work two weeks thereafter.  The employee developed symptoms while riding in a vehicle for extended periods of time.  A repeat MRI on October 26, 2001 showed a degenerative disc at L5-S1, moderate degeneration and facet hypertrophy at L4-5 with some narrowing at the left L4 nerve root, and moderate degeneration at L3-4 without significant nerve root compromise.  Dr. Bartie’s notes indicate that he read the recent MRI scan as showing that the surgery had resulted in adequately decompressed nerves.  He prescribed Neurontin to deal with the employee’s radiculitis.

The employee returned to Dr. Wilhelm, on December 28, 2001.  He started her on OxyContin at 20 mg three times per day, and increased the dosage of her Neurontin.  He also referred her to St. Paul Neurology Clinic.  At her first appointment on January 21, 2002, the employee complained of worsening sciatic pain.  An EMG was recommended to determine whether there was ongoing nerve injury.  The EMG report, dated January 29, 2002, was negative for nerve damage.  However, the employee’s prescription for OxyContin was increased to 40 mg twice per day.

On March 21, 2002, Dr. Bartie suggested referral to a pain clinic.  In mid-April 2002, the employee was prescribed Amitriptyline for depression and to help with sleep.  The employee was treated with physical therapy and pool therapy during April and May 2002.

She was seen at United Hospital’s pain center on August 20, 2002.  A third MRI of the lumbar spine was suggested, as was an L5 nerve root block.  At that time, the employee was taking 40 mg of OxyContin twice a day, 300 mg of Neurontin three times daily, 50 mg of Amitriptyline daily, and Imitrex as needed for migraine headaches.  The possibility of a drug contract and urine monitoring was discussed but apparently was not implemented.^[1]

In early 2003, the employee was seen for chronic back pain both by Drs. Seth Rosenbaum and Frank Wei.  Dr. Rosenbaum diagnosed myofascial trigger points and recommended trigger point injections and physical therapy.  Dr. Wei diagnosed the employee as status post L5-S1 discectomy with disc protrusion on the left, obesity, deconditioning, depression, and chronic narcotic use.  He recommended a nerve root injection.

The employee had an epidural nerve root injection on February 25, 2003, but it did not prove helpful.  She was then treated with trigger point injections and additional physical therapy.  When she returned to Dr. Rosenbaum on April 8, 2003, there was no change in her reported symptoms.  She continued with physical therapy.  By the end of April, Dr. Rosenbaum described the employee’s symptoms as about 10 percent improved.  The employee underwent an intradiscal steroid injection on May 8, 2003, but reported to Dr. Rosenbaum that her symptoms had remained the same.  He referred her to Dr. Manuel Pinto at Twin Cities Spine Center.

By August 26, 2003, Dr. Wilhelm was prescribing the employee 90 tablets of OxyContin and 150 tablets of Oxycodone each month.

The employee underwent a lumbar CT scan and discogram on September 9, 2003.  The discogram was positive at the L1-2 through L4-5 levels.  Dr. Pinto had the employee fitted with a thoracolumbosacral orthosis brace to assist her in deciding whether to undergo a five-level fusion.  An MRI scan of the employee’s lumbar spine was performed on January 27, 2004.  It showed multilevel disc space degeneration at L5-S1, L4-5, and L3-4, a broad-based herniation at L2-3, a broad-based annular bulge at L3-4, and minor spondylolisthesis at L5-S1.  There was no significant nerve root impingement.            In a chart note by Dr. Pinto, dated March 8, 2004, he noted that her reported sciatica symptoms were inconsistent with her MRI findings, which showed only mild to moderate stenosis.  He concluded that surgery would not be beneficial, and recommended further conservative treatment.

On June 28, 2004, Dr. Wilhelm renewed the employee’s prescriptions for 90 tablets of OxyContin per month but increased her Oxycodone from 150 to 180 tablets.  The employee continued to see Dr. Wilhelm monthly for her medication refills.  In chart notes discussing her symptoms, he regularly referred to her pain as at “status quo.”

On July 25, 2005, Dr. Wilhelm further increased the employee’s Oxycodone to 4 tablets per day, or 240 tablets per month.  He increased her dosage of OxyContin from 40 mg twice a day to 50 mg in the morning and 60 mg at night.

On February 10, 2009, the employee and the employer and insurer entered into a stipulation for settlement.  The stipulation provided a lump sum payment of $110,000 for a full, final, and complete settlement of all claims, except for future reasonable and necessary medical care causally related to the work injury.  Specifically, the employee contended that she was permanently and totally disabled and had sustained a 23 percent whole-body disability.  The employer and insurer disputed these claims based on the medical reports by their examiner, Dr. Gary Wyard.  They contended that any symptoms attributable to the employee’s work injury had resolved and that she had been paid all benefits to which she was entitled.

On February 24, 2009, Dr. Wilhelm’s records show that the employee was still being prescribed 240 tablets of Oxycodone, but that her 50 mg of OxyContin twice a day had been increased to 40 mg OxyContin three times per day along with an additional 20 mg OxyContin at bedtime.

Dr. Wilhelm’s chart note for August 27, 2009 indicates that the employee was then taking ibuprofen several times a day, but does not indicate what condition she was treating with them, although the employee’s migraine headaches are mentioned in the same chart note.  From at least May 5, 2010, Dr. Wilhelm was prescribing 600 mg oral tablets of ibuprofen to the employee “as needed for pain,” without specifying what pain they were intended to help alleviate.

On May 31, 2012, the employee was seen by Dr. Kristen Zeller-Hack, a board certified chronic pain management physician at the request of the employer and insurer.  Dr. Zeller-Hack opined that the employee had pre-existing non-work-related chronic multilevel disc degeneration and multilevel facet arthritis.  In her view, the mechanism of the employee’s 2001 work injury would have been most consistent with a sprain/strain of the lower back.  She acknowledged that the moderate left foraminal disc herniation shown on the employee’s initial MRI study was acute and could potentially be causally related to the work injury.

In her opinion, the majority of patients with this type of injury recover in six to ten weeks following decompressive surgery with physical therapy.  Dr. Zeller-Hack felt that any symptoms resulting from the employee’s work injury had long since resolved.  She was of the opinion that the surgical treatment, the initial physical therapy, and the first two epidural injections^[2] were appropriate treatment for the work injury/aggravation.  All subsequent symptoms and treatment, however, were related only to the preexisting non work medical conditions.

Dr. Zeller-Hack further opined that the employee’s chronic narcotic medication use was not reasonable or necessary treatment for the employee’s symptoms as the records failed to demonstrate an associated improvement in function or pain control with increasing dosage and long term use.  She noted that there are significant negative side effects.  Chronic narcotic use actually creates cognitive delay, lack of motivation, and tolerance to the pain-relieving effects over time.  Hence, the pain-relieving effects of the narcotics are much less.  Dr. Zeller-Hack also questioned whether the employee was actually taking the narcotics as prescribed as the records she was provided did not contain any documented urine screening.  She recommended that the employee’s narcotic medication dosage be slowly decreased until she was weaned off the medications.

In July 2012, the insurer requested that the employee be weaned off narcotic medications.  In a chart note, dated October 17, 2012, Dr. Wilhelm recorded that the employee had weaned off the 20 mg night time dose of OxyContin and 5 mg of her total dosage (40 mg) of Oxycodone.  The employee, however, told Dr. Wilhelm that her pain was not being adequately controlled after this reduction.  Dr. Wilhelm discontinued the employee’s prescription for OxyContin and substituted 90 tablets of 60 mg extended release MS-Contin, along with 270 tablets of 600 mg of ibuprofen.

In a letter report, dated October 17, 2012, Dr. Wilhelm stated that after multiple attempts to treat her chronic lumbar pain, the employee’s physicians had concluded that “the only course of action available was pain management, including chronic narcotic medication.”  He noted that a recent attempt had been made to wean the employee off the narcotic medications, in keeping with the insurer’s request, but this resulted in a marked increase in the employee’s pain.  He stated that the employee’s narcotic medications were being switched to MS-Contin, so as to lower the costs to the insurer.  In his opinion, the employee had made a good faith effort to discontinue narcotic pain medications, but it proved impossible for her to do so.

With limited exceptions, Dr. Wilhelm’s records show the employee’s pain level as “status quo” or “unchanged” from 2008 to 2013.  He regularly noted that her condition showed “associated symptoms” of decreased activity tolerance, depression, fatigue, insomnia, and irritability.

In a letter dated April 16, 2013, Dr. Wilhelm noted that he had recommended pool therapy to help strengthen the employee’s spinal and core muscles and reduce pain.  He requested that the insurer cover the costs of the pool therapy.

On April 25, 2013, the employee filed a medical request seeking reimbursement for pool therapy and her medication expenses.  Following an administrative conference on the request, the pool therapy was denied, but the medication expenses were approved.  The employer and insurer filed a request for formal hearing, resulting in the hearing below.  Following the hearing, the compensation judge found that the employee’s MS-Contin and Oxycodone were not reasonable or necessary treatment and that they were unrelated to the employee’s work injury.  The judge also found that the employee’s prescription for ibuprofen was not related to the work injury.  The employee appeals.

In reviewing cases 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.  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, “[f]actfindings are clearly erroneous only if the reviewing court on the entire evidence is left with a definite and firm conviction that a mistake has been committed.”  Northern States Power Co. v. Lyon Foods Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).  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 the evidence or not reasonably supported by the evidence as a whole.”  Id.

The reasonableness and necessity of any given medical treatment is a question of fact for the compensation judge.  Hopp v. Grist Mill, 499 N.W.2d 812, 48 W.C.D. 450 (Minn. 1993).  Medical expenses are not to be assumed reasonable and necessary merely because they were rendered.  Wright v. Kimro, 34 W.C.D. 702, 705-06 (W.C.C.A. 1982).  Instead, “treatment should be scrutinized carefully in order to determine if a particular treatment rendered is warranted and reasonable.”  Id. at 705.

In her memorandum, the compensation judge lists a number of factors that she considered in determining that the employee’s MS-Contin and Oxycodone were not reasonable and necessary treatment.  She found the expert medical opinion of Dr. Zeller-Hack to be more persuasive than that of Dr. Wilhelm.  The compensation judge noted that Dr. Zeller-Hack correctly observed that none of the extensive treatment and care provided to the employee subsequent to the work injury was beneficial or resulted in significant relief to the employee’s low back pain.  Moreover, the compensation judge relied on Dr. Zeller-Hack’s opinion that there was no indication in the employee’s medical records that her function or discomfort improved over the twelve-year history of narcotic pain medication use.  To the contrary, “there is a potential for a paradoxical effect with chronic narcotic use, meaning a patient’s pain sensation actually increases with time, and their pain is actually worse with time on chronic narcotics.”^[3]  The compensation judge adopted Dr. Zeller-Hack’s opinion that the employee’s use of narcotic medications was not reasonable or necessary treatment.

The compensation judge, as the trier of fact, bears the responsibility to resolve conflicts in expert medical testimony.  Where there is adequate foundation for the opinions adopted by the judge, this court will normally uphold the compensation judge’s choice among medical experts.  See Nord v. City of Cook, 360 N.W.2d 337, 342-43, 37 W.C.D. 364, 372-73 (Minn. 1985).

The employee points to language in Dr. Zeller-Hack’s opinion noting that prolonged narcotic use may create cognitive delay, lack of motivation, and tolerance to the pain-relieving effects of the drugs.  The employee asserts that Dr. Zeller-Hack presumed these factors were present as a prerequisite to her opinion that the narcotic medications were not reasonable or necessary.  She contends that the doctor’s opinion lacks adequate foundation, arguing that there is no medical evidence that the employee is experiencing cognitive delay, lack of motivation, or increased drug tolerance.  We have reviewed the medical evidence and the stated rationale for Dr. Zeller-Hack’s opinion, and conclude there is sufficient factual foundation.  Dr. Wilhelm’s records support the presence of these potential effects of chronic narcotic use.  More importantly, we note that the stated basis for Dr. Zeller-Hack’s opinion was primarily that no improvement of pain control or function was documented in the medical records as associated with the continually-increasing dosages of narcotic medications.  The medical records amply support this conclusion.

We conclude that the compensation judge’s choice of medical opinion on this issue must be affirmed.

The compensation judge found that the employee’s narcotic medications MS-Contin and Oxycodone are not causally related to the February 1, 2011 work injury.  The employee argues, however, that this finding is not supported either by Dr. Zeller-Hack’s opinion or by any other medical evidence in the record.  She contends that Dr. Zeller-Hack’s report did not provide any specific opinion on whether the narcotic medications were causally related to the work injury.  Accordingly, she concludes, the compensation judge erred in finding that the employee’s medications were unrelated to the work injury.  We disagree.

We note that Dr. Zeller-Hack’s report specifically stated the opinion that none of the employee’s medical treatment subsequent to her initial physical therapy, nerve root injections, and surgery were causally related to the work-related aggravation of her preexisting chronic degeneration and chronic facet arthritis.  The employee’s narcotic regimen has continued and increased subsequent to those initial treatments.  Based on her experience, Dr. Zeller-Hack further opined that a twist/fall type injury resulting in a herniated disc resolves within months following decompressive surgery with physical therapy.  From this and other portions of Dr. Zeller-Hack’s report, the compensation judge reasonably interpreted Dr. Zeller-Hack’s opinion as concluding a lack of causal connection between the work injury and the narcotic and other medical treatment provided to the employee beyond the initial post-surgery and therapy treatment referred to above.

The compensation judge found that nothing in Dr. Wilhelm’s records specifically stated that he was prescribing ibuprofen for the employee’s back problems.  The record permits a reasonable inference that the prescription was for her migraine headaches.  The compensation judge found that the employee had therefore failed to meet her burden of proof that the ibuprofen is causally related to the employee’s work injury.

The employee points out that Dr. Wilhelm’s chart note for February 24, 2009 states that the employee’s migraine headaches “are controlled with either Excedrin or Imitrex,” and that the fact that Dr. Wilhelm has continued to prescribe ibuprofen for “pain” for more than three years clearly indicates that the ibuprofen is being prescribed for her low back pain.  While this is an equally plausible inference, the employee bears the burden of proving by a preponderance of the evidence that she is entitled to workers’ compensation benefits.  See, e.g., Fisher v. Saga Corp., 463 N.W.2d 501, 501, 43 W.C.D. 559, 560 (Minn. 1990).  Because Dr. Wilhelm’s chart note is not clear as to why the employee was being prescribed ibuprofen, we conclude that the compensation judge’s interpretation of the record was not unreasonable, and therefore, affirm the finding that the employee failed to prove that the ibuprofen was prescribed to treat the work injury.