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Disclosure of medical opinion testimony under Missouri and federal rules

Vol. 76, No. 6 / Nov. - Dec. 2020

Journal - Andrew Corkery 2

Andrew Corkery
Andrew Corkery is a partner with Boyle Brasher LLC in St. Louis. He is licensed in Missouri, Illinois, and Tennessee. Corkery focuses his practice on transportation law and medical malpractice. He is a graduate of Saint Louis University School of Law.


Presenting medical testimony is one of the most important aspects in any personal injury case. In medical malpractice cases, expert testimony is often the key to success for both plaintiff and defendant. Expert testimony is needed to prove whether the physician or health care provider met the standard of care.

Journal - Medical Opinion Testimony

Expert testimony is also needed to establish causation or to argue a lack of causation. In personal injury cases, testimony from a treating doctor or a retained expert is often key to the determination whether, or to what extent, the plaintiff is injured. When attempting to resolve or eventually trying a medical malpractice or personal injury case, both plaintiff and defendant must know what the medical testimony will be.

The first step to effective expert testimony is proper disclosure. Failure to properly disclose your expert medical opinions will prevent counsel from being able to present that testimony at trial. What is required for disclosure under Missouri rules and under federal rules is very different. A practitioner must be aware of the disclosure requirements in the court where they are practicing. The practitioner must also be aware of the required obligations when accepting the other party’s expert disclosure.

Missouri Rules for Expert Disclosures
Missouri has a very lenient requirement for what a party must do when disclosing their expert testimony. Attorneys who practice in other states, such as Illinois, or in federal court are often surprised by how little needs to be disclosed in Missouri. Under Missouri rules, a party is only required to provide the name, address, occupation, place of employment, and qualifications of the expert.2 If such information is provided on the expert’s curriculum vitae, a party may only provide a copy of that CV.3 Under Missouri rules, the party taking the expert’s deposition has to pay for the deposition; therefore, the party disclosing the expert is required to state what the expert charges for deposition.4

A party also need only state the general nature of the subject on which the expert is expected to testify.5 General nature is not a very demanding test. Missouri does not require a party to provide the opinions and basis therefore in the disclosure. Also, Missouri does not require the expert to prepare a report containing opinions.

Missouri does require the disclosure of this information by a party, even if there is a technical objection to the interrogatory seeking the disclosure. In Jones v. City of Kansas City, a party attempted to avoid disclosure of expert witnesses because the interrogatory requesting information about experts was in excess of the number of interrogatories allowed.6 The court did not allow this maneuver and held that there is no authority for “a litigant to ignore the absolute duty to disclose imposed by Rule 56.01(b)(4) merely because an expert witness interrogatory is fortuitously assigned a number beyond the number of interrogatories permitted by local court rule.”7

Once the expert is disclosed, the burden shifts to the other party to obtain that expert’s opinions and bases thereof. Rule 56.01(b)(4) allows a party to obtain discovery by interrogatories or by deposition of facts known and opinions held by any person the party expects to call as an expert at trial.8 Missouri does not allow a party to propound requests for production on an expert. The Missouri rules are designed “to protect a party from the failure of an expert to disclose his opinion or the facts that he bases that opinion on during the discovery process.”9 As with the federal rules, Missouri wants to avoid trial by ambush. This concern is especially problematic in medical malpractice cases where the medical evidence can be very technical and slight differences in opinion can have a major impact on a party’s position at trial.

If the expert changes his opinions or the bases for the opinion after the expert has been deposed, it is the duty of the party tendering the witness to disclose the new information to the opposing party.10 This principle is not intended as a mechanism for contesting every variance between discovery and trial testimony.11 Rather, its purpose is to relieve a party who is genuinely surprised at trial when the expert suddenly has an opinion where he or she had none before, renders a substantially different opinion than the opinion disclosed in discovery, uses new facts to support an opinion, or newly bases that opinion on data or information not disclosed during the discovery deposition. When an expert witness has been deposed, and before trial he or she changes his or her opinion or bases an opinion on new or different facts, it is the duty of the party intending to use the expert witness to disclose that new information to the opposing party, thereby updating the responses made in the deposition.12

Missouri Courts repeatedly state that not all variances create genuine surprise. Courts note surprise cannot be “manufactured.”13 “A party cannot claim surprise based on ‘new opinions’ as to matters about which the expert witness has not been asked during discovery.”14 Courts have held that to conclude otherwise is to promote “a form of sandbagging” in which counsel could ask general questions at the deposition but more specific questions at trial, then claim surprise at the response and seek to have the testimony excluded.15

In Williams v. Mercy Clinic Springfield Communities, the Supreme Court of Missouri recently addressed this issue in a medical malpractice case where the plaintiff obtained a verdict in excess of $29 million.16 The case involved the failure of a physician to diagnose Wilson’s disease, a rare genetic disorder that causes copper to slowly accumulate in the vital organs.17 Defendant appealed the verdict to the Supreme Court in large part based on claims that plaintiff had not properly disclosed their experts.

One of the primary issues on the appeal was the testimony of physician/life care planner Dr. Norbert Belz. Defendant claimed that at trial Belz discussed subacute necrosis for the first time.18 Specifically, Mercy Clinic asserted Belz testified for the first time at trial about the meaning of the term “subacute necrosis,” offered a new opinion about the 2017 MRI, and offered a new opinion as to when the damage to Williams’ brain allegedly occurred.19 Defendant argued that because these opinions were not stated in the deposition, the opinions should not have been allowed at trial and that defendant was entitled to a new trial.20

The Supreme Court of Missouri did not agree with defendant. It concluded Belz’s testimony regarding the concept of subacute necrosis, the 2017 MRI, and causation did not constitute surprise to defendant.21 The Court noted Belz’s trial testimony was within his area of expertise, as he was retained to perform an independent medical exam of Williams and to create her life care plan, which required consideration of Williams’ injuries, the causes of the injuries, and her current and future care needs.22 The Court noted what Belz brought to the deposition: plaintiff’s entire medical file – including the 2013 MRI report, which referenced subacute necrosis. During his deposition, Mercy Clinic questioned Belz regarding the bases for his conclusions regarding Williams’ future needs detailed in the life care plan, and Belz explained the information was from a number of sources, including Williams’ medical records.23 The Court noted that defense counsel had the opportunity to question Belz about the concept of subacute necrosis and causation, but it did not.24

The Court noted that during the time between Belz’s deposition and trial, Belz ordered the 2017 MRI of Williams. Mercy Clinic received a copy of the MRI report, and Williams’ counsel indicated to Mercy Clinic that Belz’s opinion had not changed. Based on these factors, the Court concluded it was unclear how Mercy Clinic could have been genuinely surprised by Belz’s testimony as a party cannot claim surprise based on “new opinions” the expert witness was not asked about during discovery.25 The Court found Mercy Clinic was aware Belz had relied on the 2013 MRI in formulating his life care plan for regarding the new MRI26 and concluded allowing Belz to testify regarding the 2017 MRI, the concept of subacute necrosis, and causation was not so arbitrary and unreasonable as to indicate a lack of careful consideration by the circuit court and did not affect the merits of this case.27

The defendant also challenged three points in the expert testimony of Dr. Fischer, another witness.28 Mercy Clinic argued Fischer’s trial testimony about whether Trientine caused Williams’ neurological damage, the timing of Williams’ treatment, and the significance of bilateral and unilateral tremors materially differed from his prior deposition testimony.29

The Supreme Court found,to the extent there was any variance in Fischer’s testimony regarding the Trientine, the impeachment of Fischer was an adequate remedial measure.30 The Supreme Court found that the trial court’s decision to allow Fischer to cast doubt on his previously stated opinion regarding whether Trientine caused Williams’ neurological deterioration after he viewed the 2017 MRI was not an abuse of discretion.31

For the other variances between the expert’s deposition testimony and trial testimony regarding the timing and the significance of tremors, the Court again concluded Mercy Clinic had the opportunity to cross-examine Fischer and to impeach him regarding any potential variance in his testimony, which was an adequate remedy.32 The Court concluded the decision to admit Fischer’s testimony was not an abuse of discretion.33

The detailed discussion in Williams shows that what is considered a new opinion is often not a clear-cut issue. The Missouri approach requires a detailed examination of the deposition as well as questions asked and questions that could have been asked. Further, courts are given wide discretion in how to resolve these issues. The court may determine that there is no genuine surprise, or the court may determine any inconsistency is resolved by allowing impeachment. Nothing in the rules requires that the opinion be barred, even if it is a new opinion. Thus, counsel must make certain they have explored all of an opposing expert’s opinions. Further, lawyers must make sure they explore the basis of those opinions.

The next issue to consider is who must be disclosed. Consulting expert witnesses do not need to be disclosed. Their identity and opinions are protected by work product. Non-retained opinion witnesses, such as treating physicians, do need to be disclosed.

In Beverly v. Hudak, the court addressed the issue of whether a defendant physician needs to be disclosed as a retained expert.34 The defendant’s designation of expert witnesses included the following statement: “Defendants further reserve the right to call, as non-retained expert witness, any and all of plaintiff’s treating healthcare providers, to testify about their personal knowledge of plaintiff’s conditions including standard of care, causation and damages issues.”35 The Beverly court noted that although the defendant’s disclosure plainly indicated that treating physicians might testify as non-retained experts regarding the standard of care, the disclosure did not provide the name, address, or field of any non-retained expert witness, including a party, though required by Rule 56.01(b)(5) to do so.36 The trial court overruled Beverly’s objection that Hudak should not be allowed to testify regarding the standard of care because the defendant had not identified him as an expert for this purpose. The appellate court found defendant violated Rule 56.01(b)(5) by failing to specifically identify defendant as an expert. However, in reviewing the decision, the court stated, “we consider whether the challenged act by the trial court, under the totality of the circumstances, has resulted in prejudice or unfair surprise.”37

Although the Beverly court ruled in defendant’s favor, the implication is that if the defendant is going to offer expert testimony, then the defendant needs to be disclosed. In the medical malpractice context especially, the defendant doctor should be disclosed with the specificity you would use for an expert physician.

In Wilkerson v. Prelutsky, the Supreme Court found that treating physicians do need to be disclosed by name.38 In Wilkerson, the plaintiff disclosed that it might “call as expert witnesses on damages any and all of plaintiff’s treating physicians. Said experts may testify to various aspects of the damage issues including fairness and reasonableness of the medical charges and causal relationship of the treatment provided to the carbon monoxide poisoning.”39 The trial court excluded the testimony of a non-party treating physician as a sanction for the plaintiff’s failure to specifically identify the treating physicians who would testify as non-retained experts.40 The Supreme Court noted that “[d]efendants were entitled to rely on plaintiff’s answers to interrogatories in determining who they should depose and who to select as their experts,” and the “[p]laintiff’s failure to identify [the treating physician] in her interrogatory responses could  very well have led defendants to believe that plaintiff did not consider [the treating physician] to be a potential witness in the case.”41 The Supreme Court concluded the trial court did not abuse its discretion in excluding the testimony of one of the treating physicians as a sanction for failing to comply with Rule 56.01(b)(4).42

When must experts be disclosed? Pursuant to the Missouri rules, experts must be disclosed in response to interrogatories. Generally, a party is not in possession of sufficient information to identify and disclose their expert within 30 days of receiving interrogatories. Once an expert witness is deposed, that witness is no longer a consulting expert, and their identity and opinions are no longer privileged. An attorney would not want to disclose an expert before he or she has all the information and then have the expert change their opinion as more information becomes available. In the medical malpractice context, it is in the interests of both parties to have a scheduling order in place as to when a party is required to disclose. This scenario allows for a more orderly disclosure of expert witnesses. Where a witness is not disclosed in compliance with scheduling order or local rule, it is within the discretion of the court to bar the witness.43

When an expert obtains new information and generates new opinions, it is the duty of the party’s attorney to seasonably supplement the disclosure. The term “seasonably” is left open to the court to determine the meaning. The Supreme Court of Missouri has declined to define “seasonable” in terms of a set time, but instead only that it gives the opposing party time to prepare for trial.44 Thus, in some cases even a disclosure near trial is determined to be seasonable.

Under Missouri law, independent medical examinations (IME) are controlled by Rule 60.01. Parties can seek an examination whenever the mental or physical condition of a party is at issue. Unless agreed to by the parties, a court order is required,45 which can be obtained with a showing of good cause.46 After the examination, the examiner is to provide a report detailing the findings, including all tests performed, diagnoses, and conclusions, along with all like reports.47 This report is to be delivered to the party who was subject to the examination.48 Please note that this report must be delivered – even if the party requesting the examination is not satisfied with the findings of the report. This report is not privileged. The Missouri rule does not include a time frame for production of a report. It should also be noted that the Missouri rule also allows for a vocational examination, which could be useful in personal injury cases.49

Federal Rules of Expert Disclosure
The federal rules are much more demanding with respect to disclosure of experts. Pursuant to Fed. R. Civ. P. 26(a)(2)(A), a party must identify any witness it may use at trial to present testimony under Rules 702,703, or 705 of the Federal Rules of Evidence. These rules cover all aspects of opinion testimony. Not only must these witnesses be deposed, they must also provide a written report signed by the witness. The report requirement applies to any witness who was specifically employed to provide expert testimony50 and covers any witness who we generally think of as an expert witness, for example, a doctor or someone else with specialized knowledge retained by a party to evaluate the case and then, if disclosed, testify for the party. The requirement also applies to a party’s employee whose duties include giving testimony.

The report must contain:
(i) a complete statement of all the opinions of the witness, along with the bases and reasons for them;
(ii) the facts or data considered by the witness in forming them;
(iii) any exhibits that will be used to summarize or support them;
(iv) the witness qualifications, including a list of all publications written in the previous 10 years;
(v) a list of all the other cases in which, during the previous four years, the witness testified as an expert at trial or by deposition; and
(vi) a statement of compensation to be paid for the study and testimony.51

The federal rules place a substantial burden on the disclosing party. Further, the witness has to offer the bases as well. Opinions alone are not sufficient. The witness must also disclose the relied upon facts and data. The witness does not need to disclose everything reviewed but does need to disclose everything the witness used in his or her opinion.

Fed. R. Civ. P. 37(c)(1) states that when “a party fails to provide information or identify a witness as required by [Fed.R.Civ.P.] 26(a) or (e), the party is not allowed to use that information or witness to supply evidence on a motion, at a hearing, or at a trial, unless the failure was substantially justified or is harmless.” Rule 37 allows the district court to exclude a witness as a sanction for a Rule 26 violation. The burden of establishing that a failure to disclose was substantially justified or harmless rests on the non-disclosing party.52 Counsel likely wants to avoid being in a position of proving the failure to disclose was substantially justified or harmless.

Rule 26 requires the production of all the background information described in the rule as well.53 The compilation of this information can be very time consuming. Also, when disclosing an expert, a lawyer needs to be cognizant of the expert’s testimony history and compensation to evaluate if the other party will be able to use that against the witness.

The federal discovery rules are so demanding that the other party may not take the deposition of your expert. Any information that you want your expert to express at trial must be stated in report.

In preparing reports, counselor should note that the drafts are privileged.54 Thus, the lawyer can exchange drafts of the report with the expert without concern for the other party reviewing them. This rule allows the attorney and the expert to have a complete disclosure and to address all the issues needed to be covered in trial.

Treating physicians or other non-retained expert witnesses also need to be disclosed. They fall under the category of witnesses who do not need to prepare a report.55 For these witnesses, counsel is required to provide the subject matter of the testimony and a summary of the facts and opinions to which each witness is expected to testify.56 This requirement is not as exacting as for retained witnesses because counsel does not have control over these witnesses and may have limited access.

At what point must a treating physician witness provide a report? Usually when the physician’s opinions are seen as exceeding the scope of treatment.57 The reason for requiring a report is to give fair notice of opinion testimony and time for the opponent to prepare, and to recognize that as attorneys discuss the case with their injured client’s doctor, the doctor may be asked to give opinions for the purpose of the litigation beyond those determined at the time of treatment.58

Further, the 8th Circuit has ruled that it is not sufficient when a party only discloses a physician as fact witness and produces his or her medical records. In Vanderberg v. Petco, the 8th Circuit ruled that the failure to disclose the treating physicians and a summary of the facts and opinions to which the physician is to testify resulted in the treating physician’s testimony being barred pursuant to Rule 37.59

Under federal rules, experts and reports must be disclosed by the time set forth in the scheduling order. Failure to disclose by the set date or failure to fully disclose can result in the expert being barred. Most federal districts have a scheduling order that is often put in place after the Rule 16 conference. If, for some reason, there is no scheduling order, the experts must be disclosed at least 90 days before the date set for trial or the month of trial.60 If evidence is intended solely to contradict or rebut evidence on the same subject matter as the experts disclosed by the other party, those disclosures must be made within days of the other party’s disclosure.61

Independent Medical Exams under the federal rules are controlled by Fed. R. Civ. P. 35.The requirements of the rule are very similar to the Missouri rule on IMEs. Courts are split on whether the completed IME report is due at the same time of the expert reports.62 One court has found that the Rule 26 deadline does not apply because the production of the IME report is only triggered when it is requested by the examining party.63

The federal rules are clearly more demanding than Missouri rules with respect to disclosures made regarding expert testimony. However, it may benefit the practitioner to prepare for state disclosure in the same manner he or she would prepare for a federal disclosure. The federal disclosure requires quite a bit of time and planning in preparation. There may even be times in Missouri cases where it is advantageous to have your expert prepare a report. A lawyer has to know exactly what the expert’s opinions are and how the expert is going to express those opinions well before a deadline. It is good practice to be this prepared in state court as well. Under Missouri rules, the attorney does not have to disclose all the opinions, but will benefit if he or she has a very clear understanding of what the experts are going to say and how they are going to say it. This knowledge puts the attorney in a much stronger position as he or she plans a case, conducts discovery, and prepares for trial.

1  Andrew Corkery is a partner with Boyle Brasher LLC in St. Louis. He is licensed in Missouri, Illinois, and Tennessee. Corkery focuses his practice on transportation law and medical malpractice. He is a graduate of Saint Louis University School of Law.

2  Missouri Rule 56.01 (b)(4)(a).



5   Id.

6Jones v. City of Kansas City, 569 S.W.3d 42 (Mo. App. W.D. 2019).

7Id. at 61. See also Tate v. Dierks, 608 S.W.3d 799 (Mo. App. W.D. 2020).

8Beverly v. Hudak, 545 S.W.3d 864, 869 (Mo. App. W.D. 2018).

9Sherar v. Zipper, 98 S.W.3d 628, 633 (Mo. App. W.D. 2003).

10Sherar, citing Snellen ex rel Snellen v. Capital Region Med. Ctr., 422 S.W.3d 343, 353 (Mo. App. W.D. 2013).

11Sherar, 98 S.W.3d at 634.

12Id. See also Matter of Care and Treatment of Aaron Sebastian, 556 S.W.3d 633 (Mo. App. S.D. 2018).

13Beverly v. Hudak, 545 S.W.3d 864 (Mo. App. W.D. 2018).



16Williams v. Mercy Clinic Springfield Communities, 568 S.W.3d 396 (Mo. banc. 2019).

17Id. at 404.

18Id. at 417.



21Id. at 418.

22Id. at 417.

23Id. at 418.







30Id. at 419.




34Beverly v. Hudak, 545 S.W.3d 864, 869 (Mo. App. W.D. 2018).




38Wilkerson v. Prelutsky, 943 S.W.2d 643 (Mo. banc 1997).

39Id. at 649.

40Id. at 648.



43Ellis v. Union Electric Co., 729 S.W.2d 71 (Mo. App. E.D. 1987).

44Giddens v. Kansas City So. R.Y. Co., 29 S.W.3d 813 (Mo. banc 2000).

45  Missouri Rule 60.01(a)(1).




49  Missouri Rule 60.01(a)(2).

50  Fed. R. Civ. P. 26(a)(2)(B).


52Vanderberg v. Petco Animal Supply Stores, Inc., 906 F.3d 698 (8th Cir. 2018).

53  Fed. R. Civ. P. 26(a)(2)(B).

54  Fed. R. Civ. P. 26(b)(4)(B).

55  Fed. R. Civ. P. 26(a)(2)(C).

56  Fed. R. Civ. P. 26(a)(2)(i) and (ii).

57Crabbs v. Wal-Mart Stores, Inc., 2011 WL 499141 (S.D. Iowa 2011).

58Meyers v. Nat’l R.R. Passenger Corp., 619 F.3d 729, 734-35 & n.3 (7th Cir. 2010).

59Vanderberg v. Petco Animal Supply Stores, Inc., 906 F.3d 698 (8th Cir. 2018).

60  Fed. R. Civ. P. 26(a)(2)(d)(i).

61 Id.

62Waggoner v. Ohio Central R.R., 242 F.R.D. 413 (S.D. Ohio 2007).

63Id. at 414.