The employer and insurer appeal from the compensation judge’s determinations that the employee’s 2007 work injury aggravated her pre-existing condition and that the employee had not reached maximum medical improvement from her work injury.  We affirm.

Shirley Miller, the employee, began working for McKesson Corporation as a computer software consultant in healthcare in April 2005.  She did extensive traveling in her job as the head of a consultant team and resided in the Atlanta, Georgia, area. In 2005, she was injured in a work-related motor vehicle accident in Illinois while working for McKesson.  In 2007, she was injured in a work-related slip and fall accident in Minnesota while working for McKesson.  The issues for the compensation judge at the hearing were whether the injuries she sustained to her neck and low back in 2005 were aggravated by the 2007 work injury and whether the employee had reached maximum medical improvement [MMI] from her 2007 work injury.

The employee’s 2005 work injury happened when the car she was driving was stopped at a stop sign and was rear-ended by another vehicle.  She treated for her injuries with physicians in Atlanta.  In July 2006, a neurosurgeon performed a cervical discectomy and decompression with fusion at C5-6.  The employee also had low back problems and received conservative medical care - medications and physical therapy.  The employee had continuing physical restrictions from her 2005 injury and was working within those restrictions full-time at her regular job when she was injured again in 2007.

On July 17, 2007, the employee was visiting a hospital in St. Paul to call on a customer.  She slipped on water on the floor and fell forward, extending her arms to break her fall.  The employee testified that she had immediate neck and left shoulder pain.  She was seen in the emergency department of the hospital and was given a diagnosis of a neck sprain.  Subsequent medical care was in the Atlanta area.

The 2007 injury was admitted by the employer and insurer and Minnesota workers’ compensation benefits were paid.  The employer and insurer filed a petition to discontinue benefits on January 12, 2009, alleging, in relevant part, that the employee’s 2007 work injury involved only her left shoulder and that she had reached MMI from that condition in November 2008.  The petition was heard by a compensation judge on March 10, 2009.

In his Findings and Order, issued on May 1, 2009, the compensation judge determined that the 2007 work injury had aggravated the employee’s cervical and low back condition and that she had not reached MMI from the 2007 injury.  The petition filed by the employer and insurer was denied and the employer and insurer have appealed.

At the hearing the employer and insurer argued the employee did not injure her neck and low back in 2007, and that any symptoms she had with her neck and low back were the result of the 2005 injury.  They alleged that in 2007, the employee had injured only her left shoulder and that the employee had reached MMI on the left shoulder in November 2008.  The employee did not dispute that her left shoulder was injured in 2007 or that, with regard to the left shoulder, she was at MMI, but argued that she aggravated her neck and low back in 2007 and since she was not at MMI for those conditions, she was not at MMI for the 2007 injury.

After considering the evidence, the compensation judge accepted the employee’s position.  The question for this court is not whether we would have reached the same conclusion or whether a different conclusion could have been supported by the evidence.  The issue here is simply whether the compensation judge’s decision is supported by substantial evidence.  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 37 W.C.D. 235 (Minn. 1984).  If substantial evidence supports the compensation judge’s decision, it must be affirmed.

In his findings, the compensation judge referred to the “credible” testimony by the employee that the 2007 injury had aggravated her neck and lower back.  The employer and insurer seek to raise doubts about this testimony but this court has long held that the assessment of credibility of a witness is the unique function of the trier of fact.  Brennan v. Joseph G. Brennan, M.D., P.A., 425 N.W.2d 837, 41 W.C.D. 79 (Minn. 1988); Runkel v. University of Minn., 62 W.C.D. 302 (W.C.C.A. 2002).

Further, while the employee had ongoing work restrictions following the 2005 injury, she was able to perform her regular job with those restrictions until she was injured in 2007.  After the 2007 injury, the employee was off work from September 2, 2007, to January 6, 2008, and from May 14, 2008, to November 15, 2008.  According to her medical records, these absences were due not only to her shoulder problems but also as the result of her increased symptoms in her neck and low back.

The compensation judge also referred to the opinion of Dr. Vincent Boswell, an orthopedist in Atlanta, who saw the employee on behalf of the employer and insurer.  In his October 26, 2007, report, Dr. Boswell indicated that the employee’s cervical and lumbar symptoms were worsened by the 2007 injury.  His full opinion is difficult to determine however.  On the one hand, he states that all of the employee’s treatment as of the date of his exam “was reasonable and necessary for the injury sustained on July 17, 2007.”  On the other hand, Dr. Boswell stated the 2007 injury was not the “proximate cause of the employee’s complaint of cervical spine pain, left upper extremity pain, low back pain, and left lower extremity pain.”  Of course, proximate cause is a legal conclusion, not a medical issue, and proximate cause is not the legal standard for causation in Minnesota workers’ compensation cases.  Dr. Boswell’s attempt to address this question in a subsequent report provided little, if any, clarification.

The compensation judge reviewed the records from Dr. G. Kevin Perdue, the employee’s treating doctor.  In his first visit with the employee after the 2007 injury, on August 2, 2007, Dr. Perdue stated the employee was complaining of neck and shoulder pain after her fall.  On September 4, 2007, Dr. Perdue stated in his records that the fall had exacerbated the employee’s neck and back pain.

In their brief, the employer and insurer argue that the compensation judge erred in disregarding the opinions of their IME doctors, Dr. Boswell and Dr. Paul Wicklund.  We disagree.  As we have pointed out, Dr. Boswell’s medical opinion is not clear.  Dr. Wicklund performed only a medical record review and never evaluated or took a history from the employee.  In a case in which the issue was whether previously injured parts of the body were affected by the more recent work injury, the compensation judge gave this opinion minimal weight.  The compensation judge did not err in doing so.

This issue was a difficult one for the fact finder.  As is to be expected, treating doctors were more concerned about treating the employee’s condition than in fixing liability on either the 2005 or 2007 work injuries.  The employer and insurer have provided a detailed recitation in their brief of the employee’s voluminous medical records, highlighting phrases and sentences which seem to indicate that all of the employee’s symptoms predate her 2007 injury.  We would simply note that the existence of such statements does not mean that the conclusions drawn by the compensation judge from the entire evidence were in error.  We conclude substantial evidence exists to support the compensation judge’s determination.

The employer and insurer also appeal from the compensation judge’s determination that the employee has not reached MMI for her 2007 work injury.  MMI for an injury does not occur unless there is evidence of no further significant improvement for all conditions encompassed by the work injury. Further, a medical report must be served on the employee stating that MMI has been found for all conditions. Woldmoe v. Knight Ridder, 62 W.C.D. 1 (W.C.C.A. 2002). We find no report in the record meeting that requirement.  While Dr. Boswell, in his October 2008 report, refers to the employee’s cervical and low back conditions, he finds MMI only with respect to the left shoulder.  According to the insurer’s disability case manager, Dr. Perdue referred only to MMI for the low back in November 2008.  The employer and insurer fail to cite any evidence that MMI was reached for that portion of the work injury involving the cervical spine.

The employer and insurer have also asserted that the compensation judge erred in issuing a finding that the employee was “entitled” to further treatment because this finding was on an issue not before the compensation judge.  There is no order by the compensation judge for medical treatment.  The compensation judge was identifying further treatment which had been recommended to the employee as evidence that the employee was not yet at MMI.

The decision of the compensation judge is affirmed.