The employer and insurer appeal from the judge’s finding that the employee sustained a work-related injury on November 3, 2006, and that a three-level fusion was reasonable and necessary to treat that condition.  We affirm.

The employee began work for Northwest Airlines [the employer] as a baggage handler on July 6, 2006.  His job required him to load or unload several hundred bags per flight, each bag weighing 30 to 60 pounds, and he was often required to work in a bent over position inside the belly of the aircraft.  Within weeks of starting that job, he developed back soreness, which he treated with over-the-counter medications.

On November 3, 2006, just after he finished loading a plane, the employee experienced severe low back pain when he bent over to take off the knee pads that he was required to wear for his job.  He was taken by ambulance to Fairview Southdale Hospital.

When seen by Dr. Frank Wei on November 10, 2006, the employee was complaining of acute low back and bilateral leg pain, more on the left than the right.  Dr. Wei recorded that the employee had been “just bending over to remove some knee pads when his back went out.”  The doctor suspected a disc herniation.

An MRI scan was performed on November 22, 2006.  The radiologist’s impression was “posterior herniation at L5-S1 with mild impression upon the bilateral descending S1 nerve roots.”  A right epidural injection, performed on November 24, 2006, was ineffective.

The employee was examined by Dr. Charles Watts on December 11, 2006.  Dr. Watts recorded that, “on November 3, 2006, while at work, [the employee] had just completed loading an aircraft and was on the ramp bending over to take off his kneepads and had the acute exacerbation of severe pain in his back radiating into his left leg.”  Dr. Watts reviewed the MRI and opined that the employee “has degenerative disc disease predominantly at the L5-S1 level with a broad-based central disc herniation which is more prominent towards the left side and appears to cause some degree of impingement of the exiting S1 nerve root.”  Noting the employee’s use of MS Contin, Vicodin, and Valium for pain control, the MRI findings, and his findings on examination, Dr. Watts recommended surgery.

On December 22, 2006, the employee underwent a left L5-S1 facetectomy, foraminotomy, and microdiscectomy performed by Dr. Watts.  In his operative report, the doctor indicated that he had found a broad-based disc fragment that was causing pressure on the S1 nerve root.  That nerve root was decompressed, leaving no evidence of impingement.

Between December 27, 2006, and May 3, 2007, the employee made 13 calls or visits to medical providers, complaining of severe pain.

On May 10, 2007, the employee underwent an MRI that showed a mild broad-based disc bulge with minimal effacement of the anterior thecal sac at L4-5, and a moderate posterior disc herniation causing mild indentation of the thecal sac, impressing upon the bilateral descending S1 nerve roots.  A right L5-S1 transforaminal perineural epidural injection performed on May 22, 2007, provided no immediate relief, but the employee later reported complete relief for 4-5 hours after the procedure.  Lumbar discography performed on June 13, 2007, identified concordant pain at L5-S1, but no pain at L4-5.

On August 9, 2007, the employee underwent a L5-S1 posterior interbody fusion with instrumentation, performed by Dr. David Kraker.

The employee was seen in the emergency room of Unity Hospital on October 28, 2007, complaining of increased low back and right buttock pain after bending over.  He was given morphine, Vistaril, and Valium and noted improvement of his symptoms.

When seen by Dr. Kraker on November 20, 2007, the employee noted good resolution of his left leg pain but reported intermittent left buttock pain and continued low back pain.  The employee also reported that he was taking up to four Vicodin each day, without relief.

On January 23, 2008, a limited CT of the lumbar spine at L4-5 and L5-S1 was read to show a solid interbody and posterior spinal fusion at L5-S1, with mild residual narrowing of the neural foramina and mild spondylosis at the supra-adjacent L4-5 level.

The employee was seen at the emergency room of Unity Hospital again on February 3, 2008, complaining of back pain and a contusion to his chest after a fall on ice.  He was given morphine and Vistaril at the hospital and prescribed Flexeril and Percocet.

The employee underwent surgery on March 18, 2008, for removal of instrumentation at L5-S1.

When seen by Dr. Kraker again on July 1, 2008, the employee reported the recent development of progressive right leg pain and swelling in his right ankle.  He was given a Medrol Dosepak and a refill of Vicodin.

On July 16, 2008, the employee was taken by ambulance to the Unity Hospital emergency room after falling down four steps, with apparent loss of consciousness.  He complained of shoulder pain, significant low back pain, and pain in the back of his head.  He was given morphine in the ambulance, which he did not find effective.  At the hospital, he was given Dilaudid and was admitted, but he was discharged the next day.

A right L5-S1 transforaminal epidural steroid injection performed on July 23, 2008, did not provide the employee with any pain relief.

The employee was seen on July 25, 2008, by Dr. Anne-Marie Mischel, in follow up for the fall down the stairs.  Among her diagnoses was chronic low back pain with “concern for possible over reliance on narcotic medication.”

The employee was seen by orthopedic surgeon Dr. Daryll Dykes on August 13, 2008, for ongoing low back and right leg pain.  Dr. Dykes noted that the employee had not seen any significant improvement in his pain after his fusion surgery and subsequent hardware removal and that the pain had progressively worsened.

The employee underwent discography on September 10, 2008, that showed 7.5/10 concordant pain at L3-4 (low back) and 9.5/10 concordant pain at L4-5 (low back and right leg), with only minimal nonconcordant localized pressure at L2-3.  L3-4 and L4-5 were considered to be abnormal disc morphology.  According to the report from a CT scan performed post-discography that same day, “fusion integrity could not be assessed with certainty.”  The CT also showed internal disc disruption at L4-5, with contrast leakage posterolaterally and laterally on the right, and internal disc disruption at L3-4, with circumferential contrast leakage and minor annular bulging.

On September 17, 2008, Dr. Dykes noted that he had reviewed the discography and CT scan and that the scan showed “a solid partial fusion.”  He went on to note that there “is not an abundant fusion mass across the majority of the disc space.”  Concluding that the employee’s pain clearly originated from the L3-4 and L4-5 levels, he recommended a combined anterior/posterior anterior interbody fusion at L3-4 and L4-5, with augmentation of the L5-S1 fusion, and posterior decompression, fusion, and instrumentation from L3 to S1.

Dr. Edward Szalapski examined the employee on behalf of the employer and insurer on November 4, 2008.  By way of history, Dr. Szalapski recorded that the employee had been loading a DC9 on November 3, 2006, and while doing so had “a nuisance ache” in his back.  Then, after loading the plane, the employee had bent down to remove his knee pads and “had a sudden paroxysm of low back pain and pain into the left lower extremity.”  Dr. Szalapski concluded that the employee had degenerative disc disease of the lumbar spine, which was exacerbated by an acute disc herniation at the L5-S1 level in November of 2006.^[1]  It was also his opinion that the activity of bending over to remove knee pads was “more trivial than activity when patients suffer a disc herniation when they sneeze or strain on the toilet.”  He therefore viewed it as “a spontaneous disc herniation, not a work-related disc herniation.”  He went on to disagree with Dr. Dyke’s recommendation for further surgery, stating that, on CT scan, the L5-S1 fusion was “clearly quite solid” and did not require augmentation and that the results from three-level fusion for degenerative disc disease/discogenic pain “are very poor.”

In an addendum report written on December 17, 2008, after his review of the actual scans, Dr. Szalapski opined that the scan of November 22, 2006, did not show a frank herniation but rather a disc bulge at L5-S1.  He further opined that this was “simply a degenerative bulge” and that the employee was suffering from degenerative disc disease and not an acute injury.  He went on to state that it was no surprise that the employee had not done well after discectomy surgery and that the employee’s reliance on narcotic medication was not reasonable.

On February 4, 2009, the employee filed a claim petition seeking approval for the back surgery recommended by Dr. Dykes.  The employer and insurer answered, denying liability for the surgery based on the opinions of Dr. Szalapski.

Dr. Dykes wrote a letter to the employee’s attorney on March 24, 2009, stating that he disagreed with Dr. Szalapski’s diagnosis, his finding of a solid fusion, and his opinion recommending against further surgery.  Dr. Dykes opined that the employee had sustained an aggravation of a preexisting degenerative condition of his lumbar spine “as a result of his work-related activities of 11/03/2006.”  He explained that the employee “had what appears to be a prodrome of backache while loading an aircraft as part of his regular work activities.  This evolved to sudden severe back pain and lower extremity radicular pain prompting emergency room evaluation.”  He again recommended extension of the employee’s fusion, because “[the employee] has derangement of three intervertebral levels of his lumbar spine and . . . has yet to have definitive and appropriate treatment for this condition.”

On May 13, 2009, the employee was seen by Dr. Dykes for worsening low back and leg symptoms.  Surgery had not been approved by the insurer, and the employee was exploring Medicaid coverage because he did not think that he could wait.

On September 17, 2009, the employee underwent anterior spinal fusion at L3-4 and L4-5, with revision of the previous fusion at L5-S1.  The employee also underwent posterior fusion at L3-4, L4-5, and L5-S1; laminectomy, partial medial facetectomy, and foraminotomy for neural compression bilaterally at L3-4; and segmental pedicle instrumentation at L3-4 and L4-5.

On September 28, 2009, the employee was seen at HealthPartners for a post-operative checkup.  He reported severe wound pain but no leg pain.  About two weeks later, on October 13, 2009, Dr. Dykes noted that the employee had reported significant wound discomfort but was making satisfactory progress post-surgery, with only intermittent flare-ups of pain.

The claim petition came on for hearing on November 17, 2009.  At hearing, the employee testified that, while he still had significant pain at that time, he was no longer experiencing right leg pain and was starting to improve.

In findings and order filed on January 20, 2010, the compensation judge found that the employee had sustained an injury to his low back on November 3, 2006, which arose out of and in the course of his employment, and that the September 17, 2009, three-level fusion was reasonable, necessary, and causally related to the November 3, 2006, work injury.  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).

An injury must arise out of and in the course of the employment to be compensable.  Minn. Stat. § 176.011(16).  “In the course of” refers to the time, place, and circumstances of the injury.  In the present case, there is no dispute that the injury occurred in the course of the employee’s employment.  For an injury to “arise out of” employment, there must be a causal connection between the employment and the injury.  See, e.g., Lange v. Minneapolis- St. Paul Metro. Airports Comm’n., 257 Minn. 54, 99 N.W.2d 915, 21 W.C.D. 61 (1959).  The employer and insurer contend that substantial evidence does not support the judge’s finding that the employee’s injury arose out of his employment.  More specifically, the employer and insurer contend that “the injury occurred when the employee was removing his knee pads.  This activity is akin to removing socks or pants - - an everyday activity that is not unique to the workplace.”  In their brief, the employer and insurer focus on the “increased risk” test for compensability.  We do not find such an analysis necessary under the facts of this case.

The compensation judge did not find that the employee sustained a work injury while taking off his knee pads.  Rather, the judge explained that the employee’s work activities and the specific act of bending over to take off the knee pads caused an aggravation of a preexisting condition.

It is undisputed that the employee had worked loading a DC9 just prior to bending over to take off his knee pads on November 3, 2006.  The employee described that work as including heavy lifting in a bent-over position.  The employee also testified that his back had hurt while he was loading the plane.^[2]  Furthermore, it is undisputed that the employee was required to wear knee pads when loading/unloading a plane.

Dr. Dykes clearly opined that it was the employee’s work activities loading the aircraft and bending over to take off his knee pads that led to his injury.  The compensation judge accepted the opinion of Dr. Dykes over that of Dr. Szalapski.  A judge’s choice between expert opinions is generally upheld unless the facts assumed by the expert in rendering his opinion are not supported by the evidence.  Nord v. City of Cook, 360 N.W. 2d 337, 37 W.C.D. 364 (Minn. 1985).  With regard to causation, the employer has not argued that Dr. Dykes assumed facts that were not supported by the evidence.  Accordingly, we affirm the judge’s finding that the employee sustained a compensable personal injury on November 3, 2006.

The employer and insurer contend that the judge’s finding that the three-level fusion was reasonable and necessary is manifestly contrary to the evidence as a whole and should be reversed.  Specifically, the employer and insurer appear to be arguing that the judge’s decision was not reasonable because the employee’s treating physicians were unaware of the employee’s preexisting history of spontaneous lumbar and radicular complaints, the employee’s symptoms had not been relieved by three prior surgeries, Dr. Szalapski had opined that the surgery was not reasonable and necessary, and the employee has not benefited from the fusion.  We are not persuaded that the judge’s decision is clearly erroneous or unsupported by the record.

While Dr. Dykes’ medical records and reports do not indicate whether he was aware of the employee’s back complaints in 1997 and 1998, neither do his reports indicate that he was basing his recommendation for surgery on the assumption that the employee had never had lumbar and radicular complaints before.  It is important to note that the employee went more than eight years without treatment for his back prior to this work injury.

Dr. Szalapski opined that the employee did not need the three-level fusion because he suffered from a degenerative disc bulge and not a herniated disc.  Dr. Dykes testified that the employee needed the surgery because he herniated a disc on November 3, 2006, and, after a discectomy and two-level anterior and posterior lumbar decompression and fusion, the employee’s CT showed only a partial fusion of the L5-S1 level.

Dr. Szalapski’s opinion that the employee sustained no more than a degenerative disc bulge was based on his independent review of the November 22, 2006, MRI.  Dr. Szalapski testified that he was not surprised that the employee’s pain was not relieved by his first three surgeries, again, because the employee was treated for a herniated disc but instead had a disc bulge.  However, the November 2006 MRI was interpreted as showing a disc herniation at L5-S1 by both radiologist Dr. Gregory Snyder and by Dr. Watts.  In addition, Dr. Watts indicated that, during surgery, he found a broad-based disc fragment that was causing pressure on the S1 nerve root.  Also, the May 10, 2007, MRI was interpreted by the radiologist as showing a moderate posterior disc herniation, and Dr. Kraker, who performed the L5-S1 fusion in August of 2007, opined that the employee had a herniated disc.  Dr. Dykes opined that the employee did not experience relief from his symptoms after the first three surgeries because he has derangement at three levels that was not appropriately treated.

The employer and insurer’s argument that the employee did not benefit from the three-level fusion also lacks merit.  There is no medical opinion to that effect, and the employee testified, two months after that fusion, that his back was “starting to feel better” and that he was no longer having leg pain.

The issue of the reasonableness and necessity of a three-level fusion again comes down to a choice between expert opinions.  The compensation judge found Dr. Dykes’ opinion more persuasive.  Because the employer and insurer do not point to any facts relied upon by Dr. Dykes that are not supported by the evidence, we affirm the judge’s findings on this issue as well.  Accordingly, we affirm the judge’s findings in their entirety.