The employee appeals the compensation judge’s finding that the employee’s July 16, 2005, work injury to his low back was a temporary aggravation of a pre-existing condition, and appeals the denial of temporary total disability benefits and claim for a penalty pursuant to Minn. Stat. § 176.225.  We affirm.

On July 16, 2005, Robert T. Williams, the employee, sustained a low back injury when he lifted a patient while working as a certified nurse assistant (CNA) for Chisholm Health Center, the employer, which was insured for workers’ compensation liability by GE & Young, the insurer.  The employer and insurer denied liability, claiming that the employee’s condition was the result of a pre-existing condition.

The employee has an extensive medical history.  On October 9, 1993, he was involved in a rear-ending motor vehicle accident and sustained a mild concussion, cervical strain, abdominal contusion and quadriceps contusion.  On October 3, 1994, the employee was in another motor vehicle accident and sustained neck and abdominal injuries.  On October 3, 1995, the employee was involved in another motor vehicle accident involving the roll-over of his vehicle.  He received emergency medical treatment and was diagnosed with a L1 burst fracture.  Shortly after the accident, he underwent surgery at the Hennepin County Medical Center in the nature of an open reduction internal fixation of the thoracolumbar spine.  The employee’s discharge diagnosis was described as a spinal cord injury with cauda equina syndrome secondary to an L1 burst fracture, resulting in neurological damage that affected his bowel and bladder and resulted in his need to self-catheterize.

The employee testified that he remained off work for six to nine months after his 1995 motor vehicle accident.  In 1996, part of his surgical fusion had loosened and his surgical hardware was later removed.  In July 1997, the employee reported to the Hutchinson Community Hospital with a sudden onset of low back pain when he twisted at work.  In July 1999, the employee received emergency medical treatment after having passed out at work, and later was diagnosed with a possible viral syndrome and mild dehydration.  His chart note on that date referred to his back injury five years ago that caused some numbness and bladder symptoms.

The employee began working for the employer as a CNA in December 2002.  He testified that by that point he worked without any formal restrictions related to his pre-existing medical conditions.  On July 23, 2003, the employee sustained an admitted low back strain with muscle spasm while transferring a resident of the health center.  Dr. Charles Decker examined the employee on July 24, 2003, and diagnosed an exacerbation of chronic back pain.  A July 25, 2003, MRI indicated anterior wedging of L1 vertebral body representing an old injury, no acute compression, no disc herniation, focal kyphosis demonstrated at T12-11, and no cord abnormality.  The employee remained off work for a short period of time after his July 2003 injury and then was released to return to work by mid-August without restrictions.

The employee also sustained an admitted cervical spine injury on August 1, 2004, after lifting or moving a resident at the health center.  He remained off work as a result of that injury from August 2004 through early 2005.  The employer and insurer initially paid the employee temporary total disability benefits from August 5 through October 11, 2004, and later, pursuant to a settlement agreement, paid temporary total disability and temporary partial disability benefits between November 11, 2004, and April 23, 2005.^[1]  The employee continued to work for the employer as a CNA, until mid-July 2005.

On July 16, 2005, as the employee lifted a patient from a wheelchair to a tub chair, the patient slipped and the employee and a co-worker grabbed the patient and lifted him into the chair.  After that incident the employee’s back was very sore.  On the following Monday, July 18, 2005, the employee consulted Dr. Paul Woods, at the Adams Clinic in Hibbing, who noted in his chart note, as follows:

The employee consulted Dr. Charles Decker on July 20, 2005, at the Adams Clinic in Hibbing, reporting the incident of July 16.  At that time, he reported low back and neck pain.  Dr. Decker’s chart note provides the history from the employee that he “has had previous surgery on his back following an auto accident, but he has never had a problem like this.”  Dr. Decker diagnosed severe acute lumbar back strain and mild cervical back strain, and restricted the employee from work for one week until a follow-up appointment.

The employee testified that following this incident, he experienced new symptoms in his back and numbness in his legs, along with worsening back pain and a decreased sensation of when he needed to urinate.  On August 4, 2005, he consulted Dr. William Durie at the Duluth Clinic - Chisholm, reporting a burning-type of low back pain radiating into his buttocks and the back of his legs, along with numbness in his legs.  He also reported that “his neck, which was bothering him for quite some time, is better.”  Dr. Durie recommended an MRI scan because of the employee’s “history of back trouble and back surgery in the past.”

On August 25, the employee again consulted Dr. Durie, reporting that his back pain had worsened during the preceding weeks, and that he noticed pain extending into his buttocks and part way through the back of his legs.  On August 26, 2005, the employee underwent a lumbar MRI scan.  Other than showing further progression of the employee’s degenerative disc disease in the lower thoracic and lumbar spine resulting in further degenerative and dehydration of the discs, the MRI scan was interpreted as being essentially unchanged from the previous MRI scan of July 26, 2003.

The employee was again seen by Dr. Durie on September 19, 2005.  Dr. Durie noted that the employee’s primary complaint was persistent discomfort in the back.  The employee also reported difficulty knowing when he needed to void his bladder, but advised the doctor that he no longer had peripheral numbness or tingling.  At that point, Dr. Durie again recommended a neurosurgical consultation.

In October 2005, Dr. Decker diagnosed the employee with major depression and associated anxiety.  In early November 2005, Dr. Durie examined the employee for rectal bleeding associated with cramping.  Later that month, the employee returned to Dr. Durie, reporting that his symptoms of numbness in his upper legs and buttocks had resumed.  Dr. Durie recommended a neurosurgical consultation and continued the employee’s prescription medication.

The employee did not return to work following his July 16, 2005, injury.  His medical chart notes indicate that as of September 2005, the employee was approved to receive Social Security disability insurance, and that he began to receive benefits in January 2006.^[2]

On January 16, 2006, the employee was examined by Dr. Nolan Segal at the employer and insurer’s request.  In his report of March 27, 2006, Dr. Segal opined that the employee had a significant lumbar spine history from a combination of juvenile disc disease and secondary degenerative changes from his 1995 motor vehicle accident.  He referred to the employee’s significant compression fracture at the L-1 vertebral level, and commented that although the employee advised him of his work injury on August 1, 2004, he did not advise Dr. Segal of his July 16, 2005, injury nor his earlier motor vehicle accidents.  Dr. Segal was asked to address whether the employee’s condition was causally related to the incident or injury on July 16, 2005; his causation opinion was equivocal.  He commented that the discrepancies in initial histories provided by the employee “raise a question as to whether or not he actually sustained any injury at all on July 16, 2005,” and stated that

In April 2006, the employee reported to Dr. Durie that his pain was worsening and that he had increasing episodes of numbness in both legs and increasing spasm.  Dr. Durie’s chart note reflects that the employee had a “history of a back injury related to a MVA, but things had been stable for quite some time until the reinjury in August.”  The employee later testified that his symptoms worsened at that time even though he was not performing any physical work.  Dr. Durie referred the employee for a neurosurgical consultation.  On May 22, 2006, the employee was seen by a neurosurgeon, Dr. Edison McDaniels, II, who concluded that the employee had a significant kyphotic angulation^[3] secondary to an old L-1 compression fracture, along with chronic back pain and neurogenic bladder secondary to that compression fracture.  He recommended surgery, and on June 20, 2006, performed surgery which included osteotomies at the T12-L1 and L-2 levels, to treat the kyphosis, and insertion of surgical instrumentation.  The employee testified that the surgery significantly improved or alleviated his symptoms.

The employee had filed a claim petition on September 25, 2005, seeking temporary total disability benefits as a result of his July 16, 2005, injury.  The employee later amended his claim to allege a weekly wage of $375.60 at the time of his July 2005 injury, based on a forty hour work week, and to claim a penalty for a frivolous defense.  On August 23, 2006, during the course of litigation, Dr. Segal was deposed.  Dr. Segal opined that there was no evidence that the employee sustained a new structural injury to his back in July 2005, that his surgery in June 2006 was performed to correct the structural problems that were a direct result of the 1995 accident, and that any injury on July 16, 2005, was possibly, and at most, a low back strain with a temporary aggravation of a pre-existing degenerative condition.

The employee’s claims related to his low back condition were addressed at a hearing before a compensation judge on August 25, 2006.  In his findings and order served and filed on September 26, 2006, the compensation judge found that as a result of the incident on July 16, 2005, the employee had sustained a temporary aggravation that had fully resolved by September 19, 2005, and that his weekly wage on that date was $317.87.  The judge awarded temporary total disability benefits between July 16 and September 19, 2005.  He denied the employee’s claim for penalties under Minn. Stat. § 176.225, for a frivolous defense, concluding that penalties were not appropriate as the employer and insurer had presented viable defenses to the employee’s claims.  The employee appeals.

The employee argues that his July 16, 2005, work injury was a substantial contributing factor of his low back condition, temporary total disability from and after July 16, 2005, and his need for surgery in 2006.  The employee cites to the medical opinions of the employee’s treating physicians and the employee’s symptoms that have persisted since his 2005 injury.

The compensation judge accepted Dr. Segal’s opinion that there was no evidence that the employee sustained a new structural injury to his back in July 2005, that the 2006 surgery was done to correct the structural problems that were a direct result of the 1995 accident, and that any injury on July 16, 2005, was possibly and, at most, a low back strain with a temporary aggravation of a pre-existing condition.  The judge found that the employee’s disability after September 19, 2005, and his need for additional surgery were related to his pre-existing condition and not to his 2005 work injury.  In his memorandum, the compensation judge explained that he adopted the opinion of Dr. Segal “as being the most credible over that of the treating doctors and employee Robert Williams.”  The judge also explained that

In view of the records documenting the extensive medical treatment the employee has undergone in the past, we cannot say that Dr. Segal’s opinion is inconsistent with the employee’s medical history and records.  Although the record contains medical opinions contrary to those of Dr. Segal, it is the compensation judge's responsibility, as trier of fact, to resolve conflicts in expert testimony.  Nord v. City of Cook, 360 N.W.2d 337, 342, 37 W.C.D. 364, 372 (Minn. 1985).  Substantial evidence supports the compensation judge’s finding that the employee sustained a temporary aggravation of his pre-existing low back condition that resolved by September 19, 2005.  We conclude that this finding is not clearly erroneous, and therefore affirm.

At Finding No. 21, the compensation judge found that the employer and insurer had viable defenses to the employee’s claims and denied the employee’s claim for an additional award of penalties for an alleged frivolous delay in payment of benefits.  On appeal, the employee claims he is entitled to a penalty under Minn. Stat. § 176.225, due to the employer and insurer’s assertion of a frivolous defense.  Minn. Stat. § 176.225 provides for a penalty for delays in payment of benefits, and outlines circumstances in which payment of a penalty is appropriate, as follows:

The issue before us is whether the compensation judge erred by concluding that the employer and insurer’s delay in payment of temporary total disability benefits did not violate the provisions of Minn. Stat. 176.225 nor give rise to a penalty claim.  Whether a penalty is appropriate under Minn. Stat. § 176.225 normally rests within the sound discretion of the compensation judge. Maxfield v. Stremel Mfg. Co., slip op. at 5, 7 (W.C.C.A. Jan. 6, 1999).  An employer cannot be penalized for refusing to pay benefits which are the subject of a real controversy.  Grover v. City of St. Paul, 55 W.C.D. 397 (W.C.C.A. 1995).  An award of penalties is not appropriate where the employer and insurer interpose a good faith defense.  See Heise v. Honeywell, Inc., 48 W.C.D. 523 (W.C.C.A. 1993).

In this case, Dr. Segal’s opinion indicated that the employee’s condition and need for surgery was not work-related.  In the report he issued following his examination of the employee, Dr. Segal referred to the employee’s pre-existing medical condition and commented that the discrepancies in initial histories provided by the employee “raise a question as to whether or not he actually sustained any injury at all on July 16, 2005.”  Dr. Segal concluded that if it was determined that the employee did sustain an injury on July 16, 2005, this would be considered a temporary aggravation of a preexisting low back condition and that, “at most he would have had a low back strain with a temporary aggravation of a preexisting degenerative condition.”  He later explained the difficulty in determining a precise cause of the employee’s symptoms, and stated his opinion that radiologic studies showed that the most significant mechanical problems in the employee’s lumbar spine date back to his motor vehicle accident in 1995.  Dr. Segal, however, agreed that various causation scenarios were possible: that the employee “could have had a muscular strain in July of 2005" as a result of the lifting incident, and that this strain would have been temporary in nature; that the employee’s ongoing symptoms could be related to some of his non-neurological findings; or that the employee’s symptoms could stem from his earlier-diagnosed compression fracture and other conditions resulting from his 1995 motor vehicle accident.

The compensation judge determined that the employer and insurer had presented viable defenses to the employee’s claims and that it was not appropriate to award a penalty based on an allegation of a frivolous defense.  A defense is frivolous where it is unsupported by any substantial evidence.  Jackson v. Eveleth Mining Co., 49 W.C.D. 591 (W.C.C.A. 1993).  In view of the medical evidence in the record, including Dr. Segal’s opinions on the causation of the employee’s current condition, it was not unreasonable for the compensation judge to conclude that the defenses presented by the employer and insurer were viable and that no penalty was owed.  Even though the judge awarded a portion of the employee’s claim for temporary total disability benefits, the fact that an employer and insurer do not ultimately prevail in their defense does not necessarily create a basis for the imposition of a penalty.  Greene v. Independent Sch. Dist. No. 202, 36 W.C.D. 601 (W.C.C.A. 1984).  Under these circumstances, we conclude that substantial evidence supports the compensation judge’s finding that the employer and insurer did not offer a frivolous defense, and we affirm the denial of a penalty under Minn. Stat. § 176.225.