DEBRA M. DODGEN, Employee-Appellant, v. CASEY=S GENERAL STORES, INC., and EMC INS. COS./CCMSI, Employer-Insurer.

 

WORKERS' COMPENSATION COURT OF APPEALS

NOVEMBER 8, 2002

 

 

HEADNOTES

 

CAUSATION - TEMPORARY AGGRAVATION.  Substantial evidence supported the compensation judge=s determination that the employee=s 1997 work injury resulted in only a temporary, rather than permanent, aggravation of the employee=s pre-existing low back condition.

 

Affirmed.

 

Determined by Pederson, J., Rykken, J., and Stofferahn, J.

Compensation Judge: Joan G. Hallock.

 

OPINION

 

DAVID A. STOFFERAHN, Judge

 

The employee appeals from the compensation judge=s determination that her work injury on June 6, 1997 was temporary in nature.  We affirm.

 

BACKGROUND

 

The employee, Debra M. Dodgen, has a long history of back problems which began in July 1989 following a pregnancy. The employee was diagnosed with compression of the lateral femoral cutaneous nerve, and underwent surgery on October 27, 1989 in the form of an exploration of the left anterior iliac crest. Subsequently a disc herniation was suspected at L4-5, and in February 1990 the employee underwent surgical decompression at the L4-5 and L5-S1 spinal levels, together with inferior laminotomies at L4 and on the right at L5. An MRI on June 15, 1990 showed degenerative changes in the intervertebral discs at L4-5 and L5-S1 together with an abnormal signal enhancement which was read as consistent with epidural fibrosis.

 

          In November 1993, the employee was seen by Dr. Scott Lockwood at McKenna Hospital for back pain and right leg pain.  The employee was treated with an epidural steroid injection.  Dr. Lockwood noted that the employee  had a long history of low back pain which had improved with epidural injections in the past.  The employee returned to Dr. Lockwood in June 1994 reporting that her low back pain had returned and was now radiating all the way down the right leg.  She was given a series of epidural injections. 

 

The employee was referred to an osteopath, Dr. L T. Donovan, in August 1994 for evaluation of back and left leg pain.  She reported having had intermittent back pain since July 1989.  Dr. Donovan noted that the employee=s previous discectomy and decompression of the lateral femoral cutaneous nerve had not afforded any apparent relief of her symptoms.  He recommended physical therapy.  By October 10, 1994, the employee reported to Dr. Donovan that she was 90 percent improved.  The employee had been performing housecleaning work and reported that she was now able to clean one house per week by breaking the work up into two different days.  Dr. Donovan discontinued formal therapy and advised the employee to continue home exercises.

 

On November 7, 1994, the employee returned to Dr. Donovan and again reported that she was doing well overall, with no complaints of back or leg pain, although she had been experiencing  a feeling of Athickness@ on the bottom of her right foot.  She had limited her housecleaning work to only one house a week.  Dr. Donovan advised her to continue home exercise and follow up with him as needed. 

 

In April 1995, the employee returned to McKenna Hospital for further epidural steroid injections.  She reported that she was now having low back pain radiating into both hips.  She returned for a repeat injection on May 11, 1995, stating that the previous injection had relieved some of her pain.  However, on May 19, 1995, she went to the emergency room at the McKenna Hospital with right leg pain and swelling.  She gave a history of chronic low back and right leg pain.  The attending physician, Dr. Daniel J. Kangley, noted that a nerve block injection had been performed only eight days previously, and he limited treatment to the prescription of medications.  The employee returned for a repeat epidural injection on May 25, 1995, as she was still having pain in her low back radiating into her right leg. 

 

In September 1995, the employee saw Dr. Jorge H. Johnson at McKenna Hospital.  Dr. Johnson noted a history of prior surgery in 1992 [sic] for a herniated disc at L4-5 followed by about six months of pain relief after which the employee=s pain gradually began to recur, first in her low back, then subsequently radiating to the right buttocks, and more recently down the posterior aspect of the right leg to the heel of the right foot.  The employee reported that she had recently been having discomfort in the left anterior thigh as well.  Because of these symptoms, a repeat MRI was done.  The employee was found to have a synovial cyst on the right at L4-5, epidural scarring, and a small disc herniation.  On September 7, 1995 the employee underwent surgery in the form of a partial hemilaminectomy with removal of the synovial cyst and of small fragments of the herniated disc.

 

On October 6, 1995 the employee underwent another surgical procedure necessitated by weeping of cerebrospinal fluids from the site of the September 1995 surgery. The employee testified that she underwent physical therapy after the 1995 surgeries until early in 1996, by which point she was still having headaches but no right leg pain.  An MRI scan done in January 1996 showed a slight retrolisthesis of L4 on L5 with loss of disc height and signal changes at that level consistent with postoperative fibrosis.

 

The employee treated for abdominal pain of unknown origin at the Worthington Specialty Clinics during January, February and March 1997, and the records of her visits at that time reflect that she continued to suffer from pain and tenderness in the lumbar spine radiating to the right flank.  The employee was taking pain medications for her abdominal pain including Tylenol with codeine and regular Tylenol.

 

In the beginning of 1997, the employee began working for the employer, Casey=s General Stores.  Her work involved baking doughnuts, unloading and moving boxes of frozen bakery items, scrubbing and mopping floors, scrubbing the doughnut machine, and occasional cashiering.  On June 6, 1997, the employee slipped on a wet floor and fell, landing on her left side.  She was seen for this injury at the Worthington Regional Hospital on June 7, 1997, where she reported that her worst pain was in the coccyx with no pain higher in the back and no radicular pain in the buttocks or legs.   She was noted to have sustained mild abrasions at the proximal left forearm and had significant pain and swelling around the area of the left wrist.  Examination revealed no point tenderness except at the point of the coccyx.  An x-ray of the lumbar spine was taken which showed minimal disc space at L4-5 with some spondylolisthesis. The employee was diagnosed with a sprain of left wrist, contusion and bruising of the coccyx, and mild abrasion of the right forearm. 

 

With the exception of one day of work, the employee did not return to work from the date of injury through the date of the hearing below, February 22, 2002.  The employer and insurer accepted liability for a low back injury and paid wage loss benefits and medical expenses thereafter until at least mid-July, 2000.

 

The employee returned to the Worthington Specialty Clinic on June 12, 1997, and reported that her wrist and forearm were better, but  with prolonged standing she was having increased pain in her right leg.  Her coccyx was tender, but the sacrum was not.  The employee was given a prescription for Tylenol and Darvocet and was authorized to work.

 

On June 25, 1997, the employee contacted her osteopath, Dr. Donovan, to inform him that she had fallen and had increased low back pain.  She also was currently experiencing leg pain, numbness and tingling. He diagnosed an acute lumbar myofascial strain and contusion and recommended that the employee treat symptomatically. Dr. Donovan examined the employee again on July 2, 1997 for her low back pain.  The employee told him that she fell at work on June 6,  twisting and landing on her left side.  She related having experienced an Aelectric@ feeling in the area of her coccyx but no pain into her lower legs at the time of her injury.  Her pain had progressively increased over the next day until eventually she was having lower lumbar spine pain and pain into the right calf and knee which was she stated was the same as that which she had before her last back operation.  She now had constant lower lumbar spine pain and bilateral lower extremity pain, with numbness and tingling in both legs and on the plantar surface of both heels.  Sensory exam revealed decreased sensation over the dorsal medial aspect of the left foot.  Straight leg raising was negative bilaterally.  Dr. Donovan diagnosed a contusion of the lumbar spine superimposed on degenerative disc disease of the lumbar spine and prior lumbar discectomy.  He took the employee off work and prescribed physical therapy.     

 

When next seen by Dr. Donovan on July 17, 1997, the employee reported that her leg pain was increasing and was now worse than her back pain.  She noted that it now radiated in the right leg down to the right foot.  Dr. Donovan scheduled an MRI scan to rule out a herniated disc.  The scan was performed the following day and showed a near complete loss of disc space height at the L4 interspace, as well as degenerative changes in the facet joints resulting in mild degenerative retrolisthesis of L4 on L5.  The study was otherwise negative and no disc protrusions were identified. 

 

The employee did not obtain relief of her symptoms with physical therapy, and in August 1997 Dr. Donovan recommended a lumbar epidural injection.  The injection gave some relief of the employee=s left leg symptoms but the employee reported that her right leg symptoms had again increased in severity.  Dr. Donovan arranged for the employee to undergo a brief hospitalization for pain control and then a repeat lumbar epidural cortisone injection. 

 

The employee continued treating with Dr. Donovan through 1997 and into 1998 with slow improvement.  By mid-October 1997, she had been released to light duty work, although she had not returned to work.  On November 7, 1997, the employee reported that she no longer had leg pain.

On December 1, 1997, the employee described her back pain as similar to the level of pain she normally had experienced at the end of a work week.  A functional capacity evaluation was performed on February 9, 1998, and indicated that the employee was able to work at a light to medium physical demand level for an eight-hour day.  On February 13, 1998, the employee told Dr. Donovan that she was close to her baseline normal pain level.  Dr. Donovan opined that the employee was now at maximum medical improvement from her work related injury and did not require further active medical or surgical care.  He further concluded that the abnormality on the employee=s radiologic studies was due to her naturally occurring degenerative disc disease and her pre-existing surgical condition and was not necessarily related to her work injury. He also rated the employee as having a 3.5 percent impairment for lumbar pain syndrome, pursuant to Minn.R. 5223.0390, subp 3.  

 

Sometime thereafter the employer and insurer paid the employee $6,668.04 as and for permanent partial disability.

 

In April 1998, the employee returned to Dr. Donovan relating increasing discomfort in her back and leg with numbness and tingling into the lower right extremity down to the level of the calf.  Dr. Donovan set forth the employee=s work restrictions in a letter dated May 13, 1998.  In the letter, he noted that, in his opinion, the restrictions resulted from the employee=s pre-existing degenerative disc disease and prior surgery, and not necessarily because of the 1997 work injury.

 

The employee then began treating with Dr. Gregory F. Alvine, an orthopedic surgeon, in August 1998, following a referral by Dr. Donovan.  Dr. Alvine thought that the employee=s back pain was likely related to her severe disc space narrowing with mild retrolisthesis at L4-5.  However, he saw no good explanation in the radiologic studies to account for the employee=s right leg symptoms, which he thought to be in an S1 nerve root pattern.  He recommended that the employee undergo an EMG and nerve conduction study to determine which nerve in her right leg might be irritated.  The EMG and nerve studies, performed on August 31, 1998, were normal.  Dr. Alvine then suggested discograms be performed at L3-4, L4-5 and L5-S1 to attempt to determine the source of the employee=s pain.  The discography was unremarkable at L3-4, but showed degenerative changes and some concordant pain at L4-5.  Discography was not performed at L5-S1.

 

On September 9, 1998, Dr. Alvine suggested to the employee that she consider further surgery, since she continued to have severe pain as well as numbness and discomfort in the right foot and some numbness in the left calf.  On January 8, 1999, Dr. Alvine again saw the employee and again recommended that she undergo a fusion at L4-5 for her collapsed degenerative disk at L4-5.  The employee accepted this recommendation, and, on March 24, 1999, she underwent an anterior interbody fusion with installation of one BAK cage. On April 9, 1999, the employee reported that her right leg was much better but that she was now having some burning in the left anterior thigh and over the left knee, which Dr. Alvine attributed to a nerve root.  On May 27, 1999, the employee underwent a posterior fusion at L4-5 with pedicle screws for further stability due to the fact that only one BAK cage could be placed in the prior surgery. 

 

Following recovery from these surgeries, the employee had a resolution of her back pain but continued to have the same leg symptoms as before her surgeries.  She also required an injection for irritation of her lateral femoral cutaneous nerve which was causing her pain in the anterior thigh and the groin.  A repeat EMG was done in September 1999 to evaluate the employee=s bilateral leg pain and numbness.  The EMG was normal, with no evidence of  peripheral neuropathy or radiculopathy.

 

On December 4, 2000, Dr. Alvine recorded that the employee had been having increasing trouble over the past five weeks with right leg pain which was now in the back of the thigh and centered in the calf.  He recommended a CT myelogram.  This was performed on January 25, 2001 and showed no significant disc herniation or stenosis.  The employee=s fusion was solid, and Dr. Alvine noted that he had no good explanation for the employee=s right leg symptoms, which seemed to be along the L5 nerve root.

 

On March 15, 2001, Dr. Alvine noted that the employee still was having a lot of pain.  He suggested three treatment options:  removal of the fusion hardware on the right at L4-5; long term pain management; or the possible implantation of a dorsal column stimulator. 

 

Medical benefits from March 15, 2001 forward were paid by the Minnesota Department of Human Services, as the employer and insurer apparently denied further medical expenses at that time.

 

The employee underwent an examination by Dr. K. Stephen Kazi on April 26, 2001 on behalf of the employer and insurer. Dr. Kazi noted that the employee had a history of chronic low back pain associated with right radicular pain since 1992. Further, the MRI scan of July 17, 1997 showed severe disc space narrowing at L4-5 and degenerative disc disease at L5-S1 but no herniation. Dr. Kazi opined that, in view of the absence of complaints of back or radicular pain on either the day of the June 6, 1997 work injury or the following day, it was improbable that the work injury had caused any trauma to the lumbar spine.  He diagnosed a contusion of the coccyx and soft tissue injuries to the left wrist and left elbow from the work injury. These injuries had resolved in Dr. Kazi=s opinion. He thus attributed no permanent partial disability to the 1997 work injury.  Dr. Kazi concluded that the employee had long since reached MMI.  He considered the employee=s back and leg pain symptoms from and after June 12, 1997 solely the result of the employee=s advanced degenerative disc disease. 

 

On July 13, 2001, the employer and insurer served the employee with a Notice of Intention to Discontinue Benefits on the basis that all prior benefits had been paid under a mistake of fact. 

 

On August 10, 2001, Dr. Alvine noted that the employee was still having the right leg pain Athat she has had all along@ and that conservative measures, including a pain management program, had failed.  Since the CT myelogram had failed to show any nerve root compression, he recommended the employee undergo surgery for posterior hardware removal.  The employee underwent surgery for fusion, hardware removal and exploration of right L5 nerve root on November 14, 2001.  Subsequent to this surgery the employee reported that her headaches were now less frequent and much improved and that her leg pain was gone.  She continued to have some sacrum pain, for which physical therapy was prescribed on February 8, 2002.  

 

On September 14, 2001, the employee filed a claim petition alleging a 17.5 percent permanent partial disability and seeking payment of the medical expenses for her treatment with Dr. Alvine.  The employer and insurer filed an answer denying liability and alleging that prior payments were made under a mistake of fact. The case came on for hearing before a compensation judge of the Office of Administrative Hearings on February 22, 2002.  Following the hearing, the compensation judge found that the employee=s June 6, 1997 work injury resulted in a contusion of the coccyx and soft tissue injuries of the left wrist and elbow, both temporary in nature, and temporary exacerbation of the employee=s preexisting low back and right leg pain.  The compensation judge found that MMI had been reached effective with the service of the IME report of Dr. Kazi on July 13, 2001.  She held the employer and insurer liable for payment of medical expenses through July 13, 2001.  Finally, the judge held that the employer and insurer were entitled to a credit against future benefits in the amount of $6,668,04.   The employee appeals.

 

DECISION

 

The employee has appealed from the finding that her June 6, 1997 work injury resulted in only a temporary exacerbation to her pre-existing low back condition.  She further appeals from the MMI and permanency findings and extent of medical reimbursement awarded as resulting from the finding of a temporary, rather than permanent, injury.   

 

Three physicians expressed medical opinions directly relevant to the question whether the employee=s 1997 work injury was permanent or temporary in nature.  The employee relied on the deposition of Dr. Alvine, who testified that, in his opinion, the employee=s June 6, 1997 work injury was a permanent aggravation of her low back condition.  Dr. Kazi, on the other hand, opined that the 1997 work injury caused no aggravation to the employee=s low back condition, and that, by the time he examined the employee the employee had long since reached maximum medical improvement from the work injury with no permanent partial disability.   In February 1998, the employee=s then-treating physician, Dr. Donovan, recorded that the employee had returned to her pre-injury baseline.  He found that she was at maximum medical improvement from her work injury and did not require further active medical or surgical care.  He further opined that an abnormality on the employee=s radiologic studies was due to her naturally occurring degenerative disc disease and her pre-existing surgical condition and was not necessarily related to her work injury.

 

The compensation judge apparently rejected Dr. Kazi=s view that the employee=s work injury resulted in no aggravation to the employee=s low back condition.  She also rejected the opinion of Dr. Alvine that the aggravating effects of the 1997 injury had been permanent and instead found, consistent with the opinions and records of Dr. Donovan, that the effects of the aggravation were temporary and had resolved probably by early 1998.  The compensation judge did accept that portion of Dr. Kazi=s report which opined that the employee had sustained no permanent partial disability as a result of the 1997 work injury and had clearly reached maximum medical improvement from her work injury as of the date of Dr. Kazi=s examination in 2001. 

 

This court generally must uphold a compensation judge=s choice between the opinions of experts whose testimony conflictsunless the foundation assumed by the expert in rendering his opinion is not supported by the evidence.  Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985). 

 

In her brief, the employee alleges that Dr. Kazi made certain factual errors in his recital of the employee=s history such that his opinion should be deemed unreliable.  Specifically, the employee contends that Dr. Kazi was mistaken about the nature of the employee=s treatment during early 1997, when she was seen for abdominal pain of unknown origin at the Worthington Clinic.  The employee argues that Dr. Kazi mistakenly understood the employee to have been seeking treatment for her low back symptoms during this period.  The only mention of the employee=s low back in the chart notes of the Worthington Clinic during the period in question is on February 10, 1997.  On that date, a handwritten examination note does state that the employee was tender in the lumbosacral spine upon percussion.  Low back pain was one of the diagnoses listed.  Dr. Kazi=s discussion of the records in question merely states that these records Aindicate persisting pain@ in employee=s low back and that the employee Awas evaluated@ for low back pain there both in January and February 1997.  It does not appear to us that it can be clearly said that Dr. Kazi has misstated or misunderstood the content of these records.

 

The employee next asserts that Dr. Kazi mistakenly believed that the employee  continued to use certain pain medications, particularly Tylenol with codeine, for low back pain prior to the date of the 1997 work injury, suggesting that the employee was not pain-free between early 1996 and the June 1997 injury.  The employee argues that this is unsupported by the evidence. Dr. Kazi=s report cites the Worthington Regional Hospital emergency room records from June 7, 1997 as indicating that the employee was taking Tylenol with codeine for her back pain prior to the fall.  We do not know whether Dr. Kazi reviewed records from that date which were not put into evidence, but the two pages in evidence contain no reference to the employee=s use of medications.  Thus we must treat Dr. Kazi=s report as arguably factually inaccurate on this point. We do not conclude that this results in a foundational defect sufficient to require us to reverse the compensation judge=s findings, under the specific facts of this case.  First, Dr. Kazi=s opinions were based on several factual observations, and the assumption that the employee may have continued to use pain medications on a per-need basis for low back pain was not the principal basis of his opinion.  Second, it does not clearly appear that the compensation judge made the same error.  Finally, Dr. Kazi=s opinion was neither the sole expert opinion supporting the compensation judge=s determination of a temporary aggravation, nor did the compensation judge, who rejected Dr. Kazi=s opinion that the work injury did not cause even temporary aggravation of the employee=s pre-existing condition, rely significantly on the portion of Dr. Kazi=s opinion affected by this factual error. 

 

The employee has not shown any valid foundational objection to Dr. Donovan=s opinions that the effects of the employee=s work injury had returned to pre-injury baselines and that the employee had reached maximum medical improvement in early 1998.^[1]  Dr. Donovan=s opinion, in conjunction with the well-founded portions of Dr. Kazi=s opinions actually adopted by the compensation judge, provides expert medical support for the judge=s conclusions.

 

Finally, we note that Dr. Alvine=s opinion, which was the sole medical opinion supporting a finding of a permanent aggravation, was very equivocal.  In his deposition testimony, Dr. Alvine explained that his opinion was based on the employee=s claim to him that her leg pain was new, coupled with a history that this leg pain had been persistent since the slip and fall in June 1997.  When reminded that the employee had a long prior history of right leg pain, Dr. Alvine elaborated further on the basis for his opinion:  AYou=re right, she=s always had right leg pain, and the same level was operated on, L4-5 and 5-1.  So one would assume that her pain would be the same.  But just in her telling me the story, she says the leg pain she was having before her or before her previous surgery was different than this pain.@  Dr. Alvine acknowledged that there was no objective evidence of any further injury to the employee=s back following the 1997 work injury, but explained that, in his view, the work injury resulted in the employee=s pre-existing condition becoming symptomatic.   The compensation judge was not unreasonable in rejecting the employee=s testimony that her symptoms, apparently identical before and after the 1997 work injury, subjectively felt different subsequent to the work injury.  A finding based on a compensation judge=s acceptance or rejection of the credibility of witness testimony must be affirmed unless clearly erroneous.  Even v. Kraft, Inc., 445 N.W.2d 831, 835, 42 W.C.D. 220, 225‑26 (Minn. 1989).  The judge=s rejection of the employee=s testimony of a subjective change in her symptoms was in essence a credibility determination which this court must affirm.  As Dr. Alvine=s opinion was based solely on this point, we are thus compelled to affirm the rejection of his opinion.

 

Overall, we conclude that the compensation judge=s findings were amply supported by substantial evidence, including expert medical opinion and the medical records and history of the employee=s symptoms.  The employee points out that the compensation judge did commit a factual error in misunderstanding the employee=s testimony as to whether her low back symptoms gave her difficulties with certain housecleaning work the employee did for private parties for a period shortly prior to the work injury.  While it does appear that the compensation judge may have misunderstood the employee=s testimony on this point, it does not appear to be central to the compensation judge=s determination nor of such magnitude as to require reversal in the light of the substantiality and extent of the other evidence supporting the compensation judge=s findings.