The employee appeals from the compensation judge’s decision denying wage loss, permanency, and medical expense benefits on causation grounds.  We affirm.

On November 18, 1980, the employee sustained an injury to his low back when he slipped while performing his job at Solar Plastics, Inc.  Over the next several years, he underwent extensive conservative treatment for low back and right leg pain, but his symptoms never completely resolved.

On June 18, 1984, the employee underwent a lumbar CT scan, which disclosed a “[h]erniated disc, L4-L5 centrally and extending to the right,” and a “[b]ulging calcified disc with bony spurring at L5-S1 with some herniation on the right which may be clinically significant as well.”  A few months later, on October 6, 1984, the employee underwent a laminectomy with excision of a free disc fragment at L4-5.

The surgery helped to alleviate the employee’s right leg pain; however, the employee continued to experience low back symptoms.  As a consequence, in August of 1985, the employee was referred to the Pilling Pain Clinic.  In a report dated August 15, 1985, Dr. Loren Pilling predicted that the employee would eventually be able to return to “full employment,” and his symptoms apparently did improve after his participation in the pain clinic program and work hardening.  However, he was unable to tolerate the twisting and bending required by his job at Solar Plastics, and he was eventually terminated from that employment.  Solar Plastics and its insurer admitted liability for the employee’s low back injury and paid various benefits, including benefits for a 20% permanent partial disability of the back.

In January of 1987, the employee and Solar Plastics and its insurer entered into an agreement to settle all claims related to the employee’s 1980 work injury, except claims for future “reasonable and necessary medical care for treatment of the effects” of the employee’s work-related back injury.^[1]  The agreement specified that Solar Plastics and its insurer “reserve[d] all their rights and defenses” as to future claims.  An award on stipulation was issued on January 30, 1987.

The employee entered the field of security work after losing his job at Solar Plastics.  On June 27, 1998, he sustained a work-related injury while employed as a security guard by ACSS.  The injury occurred when he was struck on the neck and upper back by a falling brick, which the wind had apparently pushed off the roof of a building.  The employee testified that the force of the blow drove him to his knees and caused him to lose consciousness.  However, he finished his shift and did not seek medical treatment for nearly a week.

On July 2, 1998, the employee was seen at HealthPartners for symptoms he connected to the June 27, 1998, incident.  The examining physician diagnosed an exacerbation of chronic low back pain, without radiculopathy, cervical and trapezius spasm secondary to trauma, and bilateral knee pain, soft tissue injury “probably to ligamentous structures secondary to the fall.”  A few days later, on July 5, 1998, the employee called into urgent care, complaining of worsening back pain, radiating into both legs.  While records from a July 8, 1998, office visit contain no reference to low back pain, only neck and knee symptoms, the employee was later referred to physical therapy for both a cervical strain and “lower back strain.”

The employee was prescribed a knee immobilizer and consequently developed a deep vein thrombosis, a serious complication.  The employee also developed a right shoulder AC arthrosis, as a result of the 1998 injury, and he eventually underwent surgery to treat that condition.  Medical records in 1999 contain intermittent references to low back pain; records from 2000, during which the employee received extensive treatment for leg ulcers, contain few if any references to low back symptoms.

On September 13, 2001, while employed as a security guard for General Security Services, the employee experienced a flare up of low back symptoms when his chair collapsed at work, causing him to grab the desk in front of him in order to avoid falling.  Within several days, he sought medical care from Dr. James Hart, who had been a treating physician since 1998.  Dr. Hart diagnosed a bilateral supraspinatus strain and aggravation of chronic low back pain secondary to the September 13, 2001, incident.

On October 5, 2001, Dr. Hart noted that the employee’s recent bilateral supraspinatus strain had “resolved” and that the employee’s recent lumbar strain was “resolving.”  Almost three months later, on December 28, 2001, Dr. Hart issued a report indicating that the employee had reached maximum medical improvement [MMI] from the effects of his September 13, 2001 injury, with no permanent partial disability.

The employee apparently received little additional treatment for low back symptoms until January of 2003.  According to records from a January 17, 2003, office visit, the employee reported having experienced intermittent low back symptoms since a 1980 work injury.  No mention was made of other injuries.  The examining physician prescribed medication and advised the employee to return for follow up in two weeks.  As of February 7, 2003, the employee’s back pain was “significantly better.”

When the employee was seen for low back pain again in August of 2003, the examining physician, Dr. Kimberly Cardenas, ordered an MRI scan.  That scan, performed on September 23, 2003, revealed degenerative changes from T12 through S1.  In the conclusion section of the MRI report, listed diagnoses included lumbar spondylosis and spinal stenosis; stenosis at L4-5 with a broad-based disc bulge; and stenosis at L3-4 exacerbated by ligamentum flava hypertrophy and articular facet arthrosis.

Following the MRI scan, the employee was seen by Dr. Kirkham Wood on referral from Dr. Cardenas.  In his report to Dr. Cardenas, Dr. Wood indicated that the employee had elements of degenerative spondylosis in the lower three lumbar segments, and he recommended an epidural steroid injection.

The employee was subsequently referred to Dr. Glenn Buttermann, who scheduled the employee for a discogram.  The test produced back pain at L2-3, L3-4, L4-5, and L5-S1, with symptoms most pronounced at L2-3 and L5-S1.  Given these findings, the examiner concluded that there was a very low chance of a positive outcome from surgery.  Nevertheless, on May 25, 2004, Dr. Buttermann performed a fusion procedure, from L4 to S1.  Evidence as to the success of the surgery is conflicting, but the employee testified at hearing that he continues to experience “a lot of pain in the lower back area.”

The matter came on for hearing on February 16, 2006, for consideration of the employee’s claim for medical expenses beginning in 2003, including expenses related to the fusion surgery, wage loss benefits from May 25, 2004, through July 26, 2004, and permanent partial disability benefits.  Numerous issues were disputed, including the nature and extent of the employee’s 1998 and 2001 injuries; whether the employee’s need for fusion surgery was related to the 1980, 1998, and/or 2001 injuries; whether the surgery was reasonable and necessary; and apportionment.  Resolution of these issues was complicated by the 1987 settlement agreement concerning the 1980 injury and by the fact that MIGA had assumed responsibility for the employee’s claims against General Security Services with respect to the 2001 injury.^[2]  Evidence submitted at hearing included the testimony of the employee and of the employee’s wife; the employee’s extensive medical records; and causation opinions from Drs. Buttermann, Lowell Lutter, Nolan Segal, and Mark Engasser.

In a decision issued on June 13, 2006, the compensation judge denied all claims on causation grounds, concluding that the employee’s disability and need for the treatment at issue was not related to any of the employee’s work injuries.  The judge also found that the disputed treatment, including the fusion surgery, was not reasonable and necessary.  The employee appeals.

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 (2004).  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 the 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 central issue on appeal is medical causation with respect to the employee’s low back condition from and after 2003.  The parties submitted extensive medical opinion evidence on this issue.

Dr. Lutter, who performed the employee’s 1984 laminectomy, concluded that the employee’s current disability and need for medical care, including the fusion surgery, were causally related to the employee’s work injuries in 1980, 1998, and 2001.  He apportioned responsibility for the employee’s current condition and need for treatment 60% to the 1980 injury and 20% each to the injuries in 1998 and 2001.

Dr. Buttermann, who performed the 2004 fusion surgery, similarly concluded that all three work injuries substantially contributed to the employee’s low back condition and need for treatment.  Dr. Buttermann’s apportionment opinion varied slightly from that of Dr. Lutter, however, in that Dr. Buttermann attributed liability as follows: 70% to the 1980 injury, 10% to the 1998 injury, 10% to the 2001 injury, and 10% to a preexisting condition.

Dr. Segal, ACSS’s independent examiner, testified that the employee’s low back disability for the period at issue was attributable, on a 50-50 basis, to the 1984 laminectomy surgery and to the employee’s underlying degenerative disease process.  In Dr. Segal’s view, the 1998 and 2001 injuries were temporary at best and did not contribute to the employee’s ongoing condition and need for treatment.

Finally, Dr. Engasser, Solar Plastics’ independent examiner, reported that the employee’s condition and treatment beginning in 2003 was related, entirely, to the employee’s underlying lumbar degenerative disc disease, not to the injuries in 1980, 1998, or 2001.  More specifically, Dr. Engasser wrote as follows:

Other evidence bearing on the issue of causation included the employee’s treatment records and the testimony of the employee and his wife.  The employee testified that he was never symptom-free after his 1980 work injury, that his low back symptoms increased after each subsequent work injury, and that, as a result of his increased symptoms, he was forced to curtail activities he had previously enjoyed.  The employee’s wife corroborated the employee’s account as to the worsening of his condition.

In denying the employee’s claim, the compensation judge found the opinions of Dr. Segal and Dr. Engasser more persuasive than the opinions of Dr. Buttermann and Dr. Lutter, expressly noting Dr. Engasser’s opinion that the employee’s “problem is due to lumbar degenerative disc disease as opposed to the injury in 1980.”  On appeal, the employee argues that the judge’s decision is not supported by substantial evidence, maintaining that the record as a whole compels the conclusion that the employee’s 1980, 1998, and 2001 injuries each substantially contributed to the employee’s current disability and need for treatment.  After careful review of the entire record, we find no basis to reverse.

The judge was clearly justified in concluding that the employee’s 1998 and 2001 injuries did not substantially contribute to the employee’s disability from and after 2003.^[3]  With regard to the 1998 incident, the compensation judge noted that examining physicians recommended cervical, mid back, and knee x-rays during the employee’s first post-injury consultation, but they did not order x-rays of the employee’s low back, and the low back symptoms of which the employee complained at the time were the same as or similar to the symptoms the employee had reported, periodically, since his 1984 surgery.  In fact, the employee had sought treatment for low back pain only four days before the June 27, 1998, incident.  Furthermore, no low back symptoms were noted in chiropractic records from October of 1998, when the employee was treating for a cervical strain.  This and other evidence reasonably suggests that the 1998 incident had no lingering effect on the employee’s overall low back condition.  With regard to the employee’s September 13, 2001, aggravation, Dr. Hart indicated that the employee had reached MMI from that injury, with no permanent partial disability, in late December of 2001.  And, again, both Dr. Segal and Dr. Engasser reported that the 1998 and 2001 injuries did not substantially contribute to the employee’s disability for the period at issue.

The judge’s decision regarding the 1980 work injury presents a much closer question.  Scans prior to the employee’s 1984 laminectomy disclosed degeneration at both L4-5 and L5-S1, the levels fused by Dr. Buttermann in the May 2004 surgery, and the record establishes that the employee had continuing low back symptoms and restrictions after the 1980 incident.  However, in order to reverse the judge’s denial of medical expense claims allegedly attributable to the 1980 injury,^[4] we would have to conclude that the judge erred in relying on the causation opinion of Dr. Engasser.  We find no grounds to do so.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  As Dr. Engasser noted, the employee has degenerative changes throughout his entire lumbar spine, with some of the worst symptoms apparently emanating from L2-3, a level not implicated in the 1980 work injury.  And, after all, the employee’s increased symptoms occurred some 23 years after the 1980 incident.

We are also not persuaded by the employee’s argument that the judge’s decision is contrary to the terms of the 1987 settlement agreement between the employee and Solar Plastics.  Solar Plastics expressly reserved its defenses to future medical expense claims.  As for the employee’s contention that the judge erred by failing to rule on the reasonableness and necessity of medical treatment rendered for diagnostic purposes prior to the 2004 surgery, we would observe that the employee acknowledged, at oral argument, that the judge’s findings and order cover all treatment at issue.  Moreover, at hearing, the employee did not differentiate diagnostic treatment from the expenses associated with the surgery itself, instead simply claiming all expenses as reasonable, necessary, and causally related to the injuries in 1980, 1998, and 2001.  It may be true that, in some circumstances, treatment rendered for purposes of establishing whether a medical condition is related to an admitted work injury may be compensable, whether or not causation is ultimately established.  See, e.g., Klaven v. Northwest Medical Ctr., slip op. (W.C.C.A. Sept. 24, 1991).  However, the employee did not raise this theory of compensability to the compensation judge.  Under these circumstances, we decline to remand this claim to the compensation judge for further consideration.  The judge’s decision is affirmed in its entirety.