The employee appeals from the compensation judge’s determination that the employee’s work injury resolved, arguing that the judge’s decision is barred under the doctrine of res judicata and is also unsupported by substantial evidence.  We affirm.

The employer has worked for First Transit [the employer] as a bus driver since 1979.  On April 8, 2010, the suspension on the bus the employee was driving failed suddenly, causing the bus body to drop.  The employee pulled to the shoulder and then drove the bus four or five miles back to the garage.  He testified that he drove on the shoulder, standing up, because the bus bounced so badly.

The employee testified that he began noticing back pain after finishing his shift that day, a Thursday, and that, by Monday, his legs had swollen to the point that he could not wear his shoes.  He also complained of leg pain and numbness all the way down to his toes.  The employer took the employee to see Dr. Vijay Eyunni, a doctor in the employer’s managed care plan.  Dr. Eyunni prescribed medication, referred the employee to physical therapy, and removed the employee from his driving job.  The employer then assigned the employee to light-duty work.

The employee underwent the recommended physical therapy, but he continued to complain of back pain radiating into his left leg.  On June 8, 2001, he underwent a lumbar MRI, which identified “[m]ultilevel degenerative changes with foraminal stenosis . . . at L5-S1 on the left side as a result of paracentral disk protrusion which appears to have a low profile but appears to narrow the medial exit zone.”

About three weeks later, the employee was seen by Dr. Kristen Zeller-Hack, of Summit Orthopedics, who advised the employee to remain off his driving job and to undergo injections.  A July 2010 left-sided L5 nerve root injection provided substantial relief of the employee’s symptoms.  The employee was then seen by Dr. Nicolas Wills, also of Summit Orthopedics.  The employee eventually underwent a repeat injection, which again relieved his pain, and Dr. Wills recommended that the employee undergo a L5-S1 decompression and fusion.

The employer, self-insured, had the employee evaluated by Dr. Joseph Teynor.  In his initial report, dated October 13, 2010, Dr. Teynor agreed that the employee should have surgery,^[1] but he concluded that the work injury had long since resolved and that the employee’s symptoms and need for treatment were the result of a preexisting condition.

In December of 2010, the employee filed a medical request, seeking approval of the fusion surgery that had by then been recommended by Dr. Eyunni as well as Dr. Wills.  Relying on the opinion of Dr. Teynor, the employer denied liability on causation grounds.  The matter was consolidated with a rehabilitation request and went to administrative conference.  In a decision and order pursuant to Minn. Stat. § 176.106, issued on March 25, 2011, following that conference, Compensation Judge John Ellefson “ordered that the employee’s Requests for Medical and for Rehabilitation services are granted.”  The employer filed a request for formal hearing on April 27, 2011, but, because the request was not filed within the 30 days specified by statute, Judge Ellefson dismissed the request as untimely.

In June 2011, the employer filed a petition to discontinue benefits, and that matter came on for hearing before Compensation Judge Catherine Dallner on July 27, 2011.  At that time, the employer was again contending that the employee’s injury was merely temporary and that the employee’s ongoing disability was caused solely by his preexisting condition.  The employee contended, in part, that the employer’s contention to that effect was barred by the doctrine of res judicata, given the previous administrative conference decision approving surgery; however, the employee had not yet undergone that procedure.  Evidence included medical records documenting the employee’s preexisting low back condition, updated reports from Dr. Teynor, the employee’s post-injury medical records, a causation opinion from Dr. Eyunni, and testimony of the employee, the employee’s domestic partner, and one of the employer’s safety managers.

In a decision issued on August 19, 2011, the compensation judge concluded that the employee’s April 8, 2010, work injury was merely a temporary aggravation of the employee’s preexisting condition and that the employee had fully recovered from that injury, entitling the employer to discontinue temporary total disability benefits, as requested.  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 (2010).  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).

On March 9, 2011, the parties appeared at an administrative conference pursuant to Minn. Stat. § 176.106, to determine the employee’s entitlement to the surgery recommended by Dr. Wills and to additional rehabilitation services.  In a decision and order pursuant to Minn. Stat. § 176.106, Judge Ellefson granted the employee’s requests.  According to the memorandum attached to Judge Ellefson’s decision, the primary issue was causation for the employee’s low back pain.  The employer requested a formal hearing, but the request was dismissed as untimely.

The employer subsequently sought to discontinue the employee’s temporary total disability benefits on grounds that the employee’s disability was not causally related to the work injury, and the employer again relied largely on the opinion of Dr. Teynor, who had by that time issued another report.  At the hearing on the employer’s petition to discontinue, the employee contended that Judge Ellefson’s administrative decision approving surgery was res judicata as to the issue of causation.  Judge Dallner disagreed, noting that the benefits at stake were not the same as those at the earlier administrative conference.  In the present appeal, the employee contends that Judge Dallner erred in this regard and that she “did not have jurisdiction to make a finding that contradicts a previous un-appealed Minn. Stat. § 176.106 decision.”  We are not persuaded.

In general, the principles of res judicata are applicable in workers’ compensation proceedings.  See, e.g., Alexander v. Kenneth R. LaLonde Enters., 288 N.W.2d 18, 31 W.C.D. 407 (1980).  Collateral estoppel, or issue preclusion, is a form of res judicata in which a prior judgment is conclusive in a later suit between the same parties as to determinative issues resolved in the first action.  Travelers Ins. Co. v. Thompson, 163 N.W.2d 289 (Minn. 1969).  These principles apply only to issues specifically litigated and decided in the prior proceedings.  See Fischer v. Saga Corp., 498 N.W.2d 449, 450, 48 W.C.D. 368, 369 (Minn. 1993); citing 3 Larson, The Law of Workman’s Compensation § 79.72 (f) (1992).  This court has held that an unappealed administrative decision may have some res judicata effect.  See Milosevich v. Certified Servs., slip op. (W.C.C.A. July 2, 1992).

The employee contends, essentially, that causation for his low back condition was conclusively established by Judge Ellefson’s administrative decision, because no timely appeal was taken.  It does appear that causation was the primary question at the conference level, at least according to Judge Ellefson’s memorandum, and, again according to that memorandum, Judge Ellefson resolved the issue in the employee’s favor.

We have noted, however, that problems exist in using administrative decisions to bar future claims and defenses.  Nguyen v. Anderson Automatics, Inc., No. WC09-5000 (W.C.C.A. Mar. 8, 2010).  Administrative conferences are exceptionally informal.  No record is created at the conference level; there is no sworn testimony, and there are no formal exhibits.  As such, there is seldom any conclusive indication as to what issues were actually litigated and decided, and there is virtually never any way to determine just what information the judge used to arrive at his administrative decision.  Administrative conference decisions on requests for approval of treatment not yet rendered, such as recommended surgery, raise additional issues, in that such rulings are prospective.  Relevant circumstances may change after a conference, calling into question the employee’s need for or the advisability of the approved procedure.  Given these considerations, it may be particularly inappropriate to give res judicata effect to an administrative decision concerning future treatment.

In the present case, the employee had not yet undergone the previously approved surgery by the time of the hearing before Judge Dallner.  The benefits at issue at that hearing were temporary total disability benefits, benefits not claimed in the prior litigation, and the employer submitted additional evidence not previously considered, in the form of an updated report by Dr. Teynor.  Under these circumstances, Judge Dallner did not err in failing to give res judicata effect to the administrative decision on surgery issued by Judge Ellefson.

Dr. Teynor concluded that the employee’s work-related low back injury was merely a temporary aggravation of the employee’s underlying, preexisting degenerative low back condition, for which the employee had received treatment prior to the work injury, and, according to Dr. Teynor, the work injury had long since resolved by the time of his examination.  Dr. Eyunni, one of the employee’s treating physicians, disagreed, relating the employee’s ongoing disability and need for treatment to the work injury.  Compensation Judge Dallner accepted the opinion of Dr. Teynor, explaining in her memorandum, in part, as follows:

In his argument on the issue, the employee contends that the compensation judge did not adequately review the medical records upon which Dr. Teynor relied in rendering his opinion; “[r]ather, she adopted his opinion without reviewing the medical evidence.”  However, it is evident from her decision that the compensation judge reviewed the employee’s medical records in some detail.  We are also unpersuaded by the employee’s argument that Dr. Teynor was incorrect when he noted physicians’ failure to document objective findings until about three months post-injury.  The examples the employee gives to refute Dr. Teynor’s conclusion on this point are virtually all subjective: the employee’s testimony about the symptoms he experienced, and what the employee reported to his physicians on the dates of various cited examinations.^[2]

A compensation judge’s choice between conflicting expert opinions is usually upheld unless the facts assumed by the expert are not supported by the record.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  In the present case, we cannot conclude that the compensation judge erred in relying on the opinion of Dr. Teynor.  We therefore affirm the compensation judge’s decision in its entirety.