OPINION
HARTZ, Judge.Bob D. Yadon (“Worker”) appeals from a decision by the Workers’ Compensation Judge (“WCJ”) denying him benefits. Worker’s principal argument is that the WCJ abused her discretion and violated Worker’s constitutional right to due process when she converted a summary judgment hearing to a trial on the merits without proper notice and failed to grant Worker a continuance that she had promised him. Worker argues in the alternative that if this court views the WCJ’s order as a summary judgment, we should reverse the order because there were genuine issues of material fact. We affirm. Because Worker suffered no prejudice from any impropriety in the WCJ’s treatment of the proceeding as a trial and because the WCJ acted within her discretion in denying a continuance, we need not reach Worker’s alternative argument.
I. BACKGROUND
On July 12, 1990, Worker filed an Amended Claim for Workers’ Compensation Benefits based on an alleged accident occurring on April 3, 1989. After a mediation conference the mediator issued a Recommended Resolution on August 29, 1990, stating, “Claimant is not entitled to benefits at this time because he failed to establish a causal connection between an on the job injury and his present disability as a probability by expert testimony of a health care provider.” Worker rejected the Recommended Resolution because “I believe my medical condition was due to breathing of EQS [hydrogen sulfide] gases over the years I worked for Quinoco Pet Inc.” On February 14,1991, the Respondents, Quinoco Petroleum, Inc. and Liberty Mutual Insurance Company (jointly referred to as “Employer”), filed an answer including the following two affirmative defenses:
5. A causal link between disability and accident has not been shown to a reasonable medical probability.
6. Claimant’s treating physician, Dr. James Vincent, in his Physical Capacities Evaluation Form, states that he is unable to relate [Worker’s] conditions or complaints to a work related injury, and that the disease which [Worker] is suffering from is not work related.
On March 26, 1991, Employer took Worker's deposition in Sidney, Montana. Employer also took the deposition of Dr. Donald Cooper in Sidney on the same day. On March 27, 1991, Employer took the deposition of Dr. Vincent in Billings, Montana. Worker, who lived in Montana and received ample notice, did not attend Dr. Vincent’s deposition.
On April 3, 1991, Worker and Employer filed a Pre-trial Order with the Workers’ Compensation Administration. The order stated that among the issues remaining to be tried were: “3. Whether there is a causal connection between disability and occurrence.” and “4. Whether the disease which [Worker] is suffering from is work related.” The parties estimated that the trial would take three hours. The order set the trial for April 15, 1991. Worker listed Carol J. Yadon, his wife, as his sole witness. Employer listed Dr. Cooper and Dr. Vincent, both by deposition, and Worker. Worker’s list of exhibits named reports by Dr. Vincent, Dr. Cooper, and Pamela Bailey, a Montana attorney who had represented Worker. Employer listed as exhibits the depositions of Drs. Cooper and Vincent, medical records and forms, and a report of accident.
On April 5, 1991, Employer moved for summary judgment on the ground that Worker had failed “to establish that his disability is a natural and direct result of his employment as a medical probability” and that the claim was barred by untimely notice and untimely filing of the claim. Employer’s request for setting on the motion recited that a formal hearing had already been set for April 15, 1991, and requested 15 minutes for the summary judgment hearing. The notice of hearing on the motion for summary judgment set the hearing at the same time as the prior scheduled trial, with three hours allocated for the hearing. Nothing in the notice indicated that the trial was being postponed. Nor would it be reasonable to infer from the notice of hearing on the summary judgment motion that the trial was indefinitely postponed. On the contrary, because Worker and his wife would be coming from Montana, it would not make sense to postpone the trial to a later date, necessitating an additional long-distance trip for Worker and his wife.
Worker attended the April 15 proceedings without counsel representing him. (Worker stated that he had sought to obtain counsel but the attorney he had consulted was unwilling to represent him without better evidence on causation.) The proceeding began with the hearing on Employer’s motion for summary judgment. With respect to the causation issue, counsel for Employer read from pertinent portions of the depositions of Drs. Cooper and Vincent. After hearing the recitation of evidence and the argument of Worker and Employer’s counsel, the WCJ indicated her belief that the motion for summary judgment was meritorious. She offered Worker a continuance until the next afternoon, however, so that Worker could go through the depositions to see whether there was testimony favorable to his case and so that Worker would have an opportunity to retain counsel. The WCJ told Worker that if he could show her “even just a little bit of evidence” establishing causation, then she would find an issue of fact and they would go to a full trial.
Shortly after the proceeding resumed on the following day, the WCJ repeated her concern that the required evidence of causation was absent from the depositions. She then added, “If I denied the [summary judgment] motion, we would go forward with the trial and I don’t think you have any other evidence to offer me at the trial.” Worker’s wife responded that she thought that she and Worker could get evidence. But the WCJ noted that the trial would be held then, not later. The day before, when Worker’s wife had asked about getting more evidence, the WCJ informed her that there needed to be a point when collecting evidence ended.
After the parties had presented all their contentions regarding the issues of causation and notice, the WCJ stated: “Basically what we’ve done * * * is we’ve had an evidentiary hearing.” She said that she would treat Employer’s motion for summary judgment as a motion to dismiss and would grant the motion. Given that the WCJ entered findings and conclusions, it is apparent that she was referring to dismissal pursuant to SCRA 1986, 1-041(B) (Repl.1992) (dismissal at close of plaintiff’s case). We first discuss whether the WCJ improperly converted the motion hearing into a trial and then discuss whether the WCJ improperly reneged on a promise to grant Worker a continuance.
II. DISCUSSION
A. Conversion of Motion Hearing to Trial
Worker contends that his constitutional right to due process was violated by the “conversion” of the proceeding from a hearing on a motion for summary judgment to a trial. We disagree.
On its face, Worker’s contention appears correct. As Judge Donnelly’s dissent points out, the WCJ dispensed with the formalities of a trial. The WCJ should have proceeded by first stating that she denied the motion for summary judgment and then asking the parties if they wished to present opening statements and offer evidence with respect to the trial on the merits. Nevertheless, the failure to follow such procedures does not require reversal in this case. Worker was provided a full opportunity to do everything he could have done if the WCJ had proceeded in a formally correct manner. We reach this conclusion based on (1) the statutory requirement that causation be proved by expert medical testimony in workers’ compensation litigation, (2) the requirement of the Pre-trial Order that all expert medical testimony be presented through previously designated documentary evidence, and (3) the WCJ’s authority to bifurcate issues in this litigation.
NMSA 1978, Section 52-l-28(B) (Repl.Pamp.1991) states:
In all cases where the employer or his insurance carrier deny that an alleged disability is a natural and direct result of the accident, the worker must establish that causal connection as a probability by expert testimony of a health care provider * * * testifying within the area of his expertise.
If the trier of fact is not convinced of causation by the expert medical testimony, benefits must be denied. See Torres v. Kennecott Copper Corp., 76 N.M. 623, 417 P.2d 435 (1966); Perea v. Gorby, 94 N.M. 325, 610 P.2d 212 (Ct.App.1980).
Worker had ample notice that he would need to be prepared to try the case on April 15 and that a central issue would be whether there was expert medical testimony sufficient to establish causation. The Pre-trial Order listed the expert medical evidence that would be offered at the trial; it consisted solely of depositions of doctors, medical records, and medical reports. All of that evidence was available and presented to the WCJ on April 15 and 16. When the WCJ stated that Worker had no additional evidence on causation, the only response was the statement by Worker’s wife that she thought they could get additional evidence. Moreover, the parties thoroughly argued the content and meaning of the medical evidence at the motion hearing. Thus, with respect to the causation issue, the WCJ heard all the evidence and argument that she could have heard at trial. In particular, nothing could be added by sworn witnesses because the Pre-Trial Order did not allow for any live expert testimony.
Of course, there may have been significant additional evidence on such matters as the timeliness of Worker’s notice and claim and the extent of his disability. But if one issue at trial may be dispositive, the WCJ has authority to bifurcate the trial and first litigate the possibly dispositive issue. See Formal Hearing Rules, N.M. Workers’ Compensation Admin. Rule 1(A), 184 N.M.Reg. No. 1-18 (June 1989) (Rules of Civil Procedure for district courts apply to hearings before WCJ); SCRA. 1986, 1-042(B) (Repl.1992) (trial court may order separate trial of any separate issue); Ortiz v. New Mexico State Police, 112 N.M. 249, 252, 814 P.2d 117, 120 (Ct.App.1991); In re Beverly Hills Fire Litigation, 695 F.2d 207, 216 (6th Cir.1982), cert. denied, 461 U.S. 929, 103 S.Ct. 2090, 77 L.Ed.2d 300 (1983) (trial court may sever causation issue). Consequently, once the WCJ decided that Employer was entitled to judgment on the causation issue, the WCJ had no obligation to conduct a formal trial on the other issues.
In short, the WCJ’s procedure, although formally incorrect, did not prejudice any rights of Worker in the particular circumstances of this case. Here we had the unusual situation of a dispositive issue being decided on previously designated documentary evidence. A trial of the causation issue would not have looked like a typical trial m any event. We must disregard errors or defects in a proceeding which do not affect the substantial rights of the parties. El Paso Elec. Co. v. Real Estate Mart, Inc., 98 N.M. 570, 574, 651 P.2d 105, 109 (Ct.App.1982). Therefore, we do not reverse on this ground.
B. Alleged Promised Continuance
Worker also contends that the WCJ violated his right to due process by first promising a continuance to enable him to re-depose Dr. Vincent and then reneging on that promise. The statement by the WCJ upon which Worker bases this contention was made after Worker complained that Dr. Vincent’s deposition testimony was contrary to what the doctor had told Worker privately. (Worker, although given notice, did not attend the deposition of Dr. Vincent.) The WCJ stated:
Okay, but the problem is we are faced with the evidence that exists right now, and at a trial I would accept the deposition of Dr. Vincent as it’s written unless you’re going to object to that, and what you’re telling me, you’re — you’re going to object to that, all I would do is authorize you to take another deposition. So you need to think about what it is you think you could change if you had opportunity to depose the doctor.
We do not interpret the statement by the WCJ as a ruling that grants a continuance. The WCJ spoke conditionally. She said, “All I would do * * Indeed, in context it appears likely that the WCJ meant to say, “All I could do.” Also, implicit in the WCJ’s statement is that authorization of a new deposition would be conditional on a meritorious objection. We find it hard to believe that the WCJ intended to grant relief to Worker simply if Worker made an objection, regardless of the objection’s merit. Here, Worker had made no meritorious objection. On the contrary, at the beginning of the hearing on April 15 Worker had not objected to introduction of the deposition testimony. Moreover, Worker’s complaint was simply that Dr. Vincent had not testified truthfully. Insofar as Worker's concern was that he was surprised by the deposition testimony, we note that Dr. Vincent’s Physical Capacities Evaluation Form, referred to in Employer’s answer of February 14, 1991, said that he could not relate Worker’s condition to his work. Thus, Worker had ample notice of Dr. Vincent’s views. In any event, any surprise from the deposition testimony could have been obviated if Worker had attended the deposition, for which he acknowledged having received notice.
Furthermore, nothing in the record indicates that Worker believed the WCJ to have promised him the opportunity to re-depose Dr. Vincent. Worker never claimed during the proceedings that the WCJ had reneged on a promise.
Finally, and perhaps most importantly, even if the comment by the WCJ could be construed as a promise, we see no denial of due process to Woiker arising from a reconsideration of the matter by the WCJ. It is not uncommon for a judge to change a decision on a matter prior to entry of final judgment. Such a change does not infringe on the due process rights of a party when there has been no detrimental reliance by the party on the original decision by the judge. See Fox v. Doak, 78 N.M. 743, 438 P.2d 153 (1968) (error cannot be predicated on inconsistencies between judge’s oral remarks from the bench and the written decision). In this ease Worker claims no such detrimental reliance, nor do we see how there could have been any. Given the notice of the trial and the terms of the Pre-trial Order, Worker was ade-' quately advised of the need to have all pertinent evidence ready for presentation on April 15. We fail to see any way in which Worker could have had additional evidence available on April 16 if the WCJ had clearly stated on April 15 that Worker would not be permitted to re-depose Dr. Vincent.
We note that Worker does not argue that denial of a continuance would have been an abuse of discretion even if the WCJ had not purportedly promised a continuance. Because the dissent addresses that point, however, we express our view that the WCJ did not abuse her discretion in determining that Worker had already received sufficient notice and time to gather and present evidence on causation.
Worker had known of the need to obtain favorable expert medical testimony on causation at least since issuance of the Recommended Resolution, which stated that Worker was not entitled to benefits because he had “failed to establish a causal connection * * * as a probability by expert testimony of a health care provider.” This gave Worker more than seven months to prepare for the hearing. That was ample time. Indeed, this court has applauded a district judge (now a member of this court) for taking a workers’ compensation case from filing of the claim to judgment in seven months. Gallegos v. Yeargin Western Constructors, 104 N.M. 623, 623-24, 725 P.2d 599, 599-600 (Ct.App.1986). Although the dissent here notes that this case was apparently “lost in the system” at one time, we have no indication that Worker was thereby prejudiced in preparing his case.
We also find that Worker had ample time to prepare for the adverse testimony in the deposition of Dr. Vincent. In its answer two months before trial, Employer asserted that Dr. Vincent was “unable to relate” Worker’s condition to his work. Worker received proper notice of the deposition of Dr. Vincent nineteen days before trial but chose not to attend. And the transcript of that deposition was provided to Worker two days before trial. In El Paso Electric Co., we found no abuse of discretion by the trial court in permitting a party to call a witness who was added to the pretrial order only three days before the witness was to testify; we noted that the opposing party was afforded an opportunity to interview the witness over the weekend before trial. Although in El Paso Electric Co. the new witness was an expert being substituted for a previously disclosed expert, here we have a witness who had submitted a report months earlier and who had been available for questioning at a deposition almost three weeks earlier. The WCJ acted well within her discretion in ruling that Worker was not entitled to more time to prepare.1
Thus, we reject Worker’s contention that he was denied due process when the WCJ, after making the statement quoted above, did not later order a continuance to enable Worker to re-depose Dr. Vincent.
III. CONCLUSION
For the reasons stated above, we affirm the decision of the WCJ.
IT IS SO ORDERED.
BIVINS, J., concurs. DONNELLY, J., dissents.. There are two other issues discussed in the dissent which we do not address. First, Worker’s briefs on appeal do not seek relief on the ground that Dr. Cooper had failed to sign his deposition, so we need not determine what relief would be appropriate for such a violation. See State ex rel. Human Servs. Dep’t v. Staples, 98 N.M. 540, 541, 650 P.2d 824, 825 (1982) (courts should be wary of taking upon itself to raise, argue, and decide legal questions overlooked by the lawyers). Second, because the WCJ denied the motion for summary judgment, we need not decide whether the motion was untimely or otherwise procedurally deficient.