The Permissible Scope of Cross-Examination of Expert Medical Witnesses

by Christopher W. Dysart¹and Tracy L. Zuckett²

I. Introduction

In personal injury cases the verdict, and the amount of damages awarded, may ultimately turn on the jury's assessment of expert medical testimony.

An expert's testimony is difficult to attack because, unlike a fact witness, an expert's testimony consists primarily of opinions and conclusions. As stated by the Court of Appeals for the Western District:

By showing the natural bias of the lay witness, whether it be by relationship, friendship, employment or other factor, the cross-examiner brings into perspective for the jury the predisposition of the witness. In contrast, a witness appearing as a physician with strong professional qualifications has no readily discernable predisposition. The physician is a person who, it is understood, has been specially trained in clinical objectivity and scientific precision. The physician has been schooled in the ethics of the hippocratic oath and its commitment to the highest principles of idealism and virtue. The physician is seen, by virtue of his calling, as impartial. A physician is also perceived as a busy, important, intelligent person. The physician is referred to by all parties as an "expert." This "expert", by the way, is the only category of witness which the legislature has specifically authorized to "invade the province of the jury" by stating an opinion as to an ultimate issue to be decided by the trier of fact.³

In a personal injury case, medical causation must be established by scientific or medical evidence "showing the cause and effect relationship between the complained of condition and the asserted cause."⁴ An expert medical witness usually expresses an opinion on the ultimate issues of medical causation and the extent of plaintiff's damages. Section 490.065(2), RSMo 1994, states:

Testimony by such an expert witness in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.⁵

While a "trial court has broad discretion in determining the admissibility of substantive evidence, and in determining the extent and scope of cross-examination," there are limits to this discretion.⁹

The trial court has no discretion to prevent any cross-examination at all on a proper subject.¹⁰ A trial "court does not have discretion 'to exclude relevant and material'" substantive evidence because it is elicited on cross-examination.¹¹ Moreover, "[e]vidence sought by cross-examination 'should not be rejected as cumulative when it goes to the very root of the matter in controversy or relates to the main issue, the decision of which turns on the weight of the evidence introduced by the respective parties.'"¹² The trial court's "discretion regarding impeachment of a witness is similarly limited."¹³

This article will discuss five basic areas the cross-examiner should consider exploring to attack the medical expert's opinion and credibility. These include bias and pecuniary interest, prior conduct, prior inconsistent statements, hypothetical questions, and learned treatises.

II. Bias and Pecuniary Interest

It is generally proper on cross-examination to show that the expert is biased towards a party, to show that the expert is prejudiced against a party, and to show the pecuniary interest of the witness.¹⁴ Moreover, "the pecuniary interest, bias or prejudice of a witness is not collateral and can always be shown subject to the limitations 'imposed by the trial judge in his sound discretion.'"¹⁵ The scope of the inquiry into the details of the pecuniary interest, prejudice or bias is left for the trial court to decide.¹⁶ For example, in State ex rel. Lichtor v. Clark, cross-examination was proper to show that the defense medical expert derived 44% of his professional income from one law firm, the defendant's.¹⁷ The court held this fact alone was enough to question the objectivity of the expert.¹⁸ Similarly, in Callahan v. Cardinal Glennon, the Supreme Court held it was proper to cross-examine an expert physician for the defense about research grants he had received from a dismissed co-defendant, a vaccine manufacturer, Lederle Laboratories, Inc.¹⁹

The Callahan case involved the failure to properly treat an abscess approximately three weeks after an infant received a live polio vaccine, resulting in suppression of the infant's immune system and the contraction of paralytic polio. Plaintiff's counsel cross-examined an expert witness for the defense concerning "research grants he had received from Lederle Laboratories, Inc., the manufacturer of Orimune and other vaccines." The expert's direct examination testimony "was based on his editorial in the Journal of the American Medical Association. The editorial reflected very favorably on Lederle." The cross-examination showed "that financial assistance for [the expert's] department and research came through large grants from Lederle." The cross-examination also showed the expert "had testified for Lederle and other similar companies against plaintiffs in eighty to one hundred products liability or medical malpractice [cases]."²⁰ The Supreme Court concluded the cross-examination was proper to show prejudice or bias.²¹

Missouri courts also allow cross-examination of an expert regarding the compensation received while testifying in the case at bar.²² When the questioning involves compensation from previous cases, Missouri courts generally do not allow the cross-examination to proceed "unless [it] bears materially on the interest of the witness in the case in litigation."²³ Under unusual circumstances, however, the trial court may allow inquiry into the medical expert's qualifications to testify as an expert witness based on his alleged identity as a professional testifier.²⁴ In Clark, the court held, in pertinent part, as follows:

[W]here a party has raised by affidavit factual information suggestive of lack of objectivity on the part of the proposed examining physician, it is not inappropriate for the court to conduct a hearing concerning the issue of professional objectivity. Also, of course, discovery pertinent to the hearing may be authorized.²⁵

In addition to pecuniary interest, cross-examination is permissible concerning potential biases of the expert. For example, in Lammert v. Wells²⁷ "[c]ross-examination of plaintiff's medical expert concerning a history of working with "plaintiff's attorney [was] held permissible" as going to the credibility of the expert.

III. Prior Conduct

Inquiry into prior conduct of the expert witness is allowed only at the discretion of the trial judge.²⁸ Cross-examination designed to show the expert is a professional testifier is generally permitted when inquiring about specific previous instances of testimony.²⁹ In addition, Missouri courts generally allow questioning if the expert always testifies for a particular party³⁰ or for a particular type of plaintiff or defendant, such as insurance companies.³¹ In Weatherly v. Miskle,³² the court held that it was proper for the trial court to admit into evidence letters sent out by a chiropractor soliciting personal injury business from attorneys. The court found the proffered evidence was relevant to show the pecuniary interest of the witness, which can always be shown.³³ The court held the jury is entitled to know everything that might affect a witness's credibility and the weight to give his testimony.³⁴

In the Miskle case, the chiropractor had sent letters soliciting business to "2,081 attorneys."³⁵ The letter stated that chiropractic care should be considered in auto accident and work related injury cases and that the attorney should call to see "how Chiropractic [care could] effectively treat conditions regarding post-injury care," soft tissue injuries and "other accident related problems." The court held that "it may be inferred from [the chiropractor's] letter that he [was] willing to testify as an expert witness in personal injury cases."³⁶

IV. Prior Inconsistent Statements

Cross-examination on the basis the expert has made prior inconsistent statements is proper for purposes of impeachment.³⁷ Moreover, a prior inconsistent statement of a witness who is available for cross-examination may be used as substantive evidence in a civil trial.³⁸

While a "trial court has broad discretion in determining the admissibility of substantive evidence and in determining the extent and scope of cross-examination, including the impeachment of a witness by use of a prior inconsistent statement," there are limits to this discretion.³⁹

The trial court's "discretion regarding impeachment of a witness is similarly limited."⁴² The trial court "has no discretion to prevent any cross-examination at all on a proper subject.⁴³ Where a witness's prior inconsistent statement relates specifically to a paramount issue in the case, the trial court may not prevent impeachment of the witness through use of the statement."⁴⁴

In Reno v. Wakeman, the plaintiff contended the trial court committed reversable error by refusing to allow her to cross-examine a defense doctor about his deposition testimony. Plaintiff contended the doctor's deposition testimony was inconsistent with his trial testimony. During his deposition, the defense doctor testified the subsequent treating physician's treatment aggravated plaintiff's injury. At trial, however, the defense doctor testified it was the subsequent physician's inactivity that aggravated the extent of plaintiff's injury.⁴⁵

The court held cross-examination into the doctor's prior deposition testimony should have been allowed as both evidence of the matter in controversy and as impeachment evidence.⁴⁶ The court held rejection of the prior inconsistent statement was error because it "went to 'the very root 'of the matter in controversy -- causation." Excluding the prior inconsistent statement was also error because it tested the medical expert's "accuracy and credibility on a specific and paramount issue in the case."⁴⁷

On the other hand, the trial court, acting within its discretion, may prohibit extrinsic evidence of prior inconsistent statements on collateral matters.⁴⁸ Thus, it is often stated that "[c]ounsel is bound by the answer of the witness on collateral matters."⁴⁹

In Lineberry v. Shull, the court held plaintiff's counsel was properly barred from impeaching the defendant's IME doctor's credibility with an allegedly prior inconsistent statement indicating the doctor "did three to four times [more] examinations for defendants [than] for plaintiffs."⁵⁰ On cross-examination plaintiff's counsel sought to have the doctor admit he only did medical examinations for defendants. In response to the cross-examination, the doctor stated that he was unable to recall and that he didn't keep track. The court prohibited the introduction of the prior inconsistent statement reasoning as follows:

Here the allegedly prior inconsistent statement is clearly collateral. Plaintiff was trying to impeach the doctor's credibility by showing that three years ago he had testified that he did three to four times as many examinations for defendants as for plaintiffs, but in his testimony at this trial he denied that he did so and said that he did not keep track. The number of examinations that the doctor was performing for defendants three years ago was not an issue in the case.⁵¹

V. Hypothetical Questions

Hypothetical questions can be an extremely persuasive tool in the cross-examination of medical experts. By setting out a group of facts and asking the expert to hypothesize on the possible outcomes, the cross-examiner is able test the witness's knowledge and the value and accuracy of their opinion.

The "hypothetical question [need not] include all material facts in evidence, [but it] must fairly hypothesize the material facts reasonably relevant to, and justly presenting, the questioner's theory of the case."⁵⁴ As long as such facts are not contrary to the evidence, and there is no concern of misleading the jury, most courts will allow the hypothetical question to be answered.⁵⁵ In addition, where the cross-examiner uses the hypothetical to test the skill and accuracy of the expert, he or she "may be cross-examined on purely imaginary and abstract questions."⁵⁶

In Stafford v. Lyon plaintiff argued the trial court erred by allowing defense counsel to use a hypothetical question to cross-examine "a neurological surgeon who removed a ruptured disc from between plaintiff's fifth and sixth vertebrae." Defense counsel's hypothetical question assumed facts that were not in evidence. The Supreme Court of Missouri noted defense counsel's cross-examination "was testing the knowledge of plaintiff's medical witness regarding the cause . . . of ruptured discs, and the value and accuracy of his opinion regarding the plaintiff's injury." The Supreme Court of Missouri held allowing such questioning was within the trial court's discretion because "wide latitude is allowed [when cross-examining an expert witness] to test his qualifications, credibility, skill or knowledge and the value and accuracy of his opinion."⁵⁷ Hypothetical questions on cross-examination, other than those designed purely to test the skill and accuracy of the expert, must not be too broad.⁵⁸ The question posed must contain all of the essential facts necessary for the expert to give a meaningful opinion.⁵⁹

VI. Learned Treatises

Another effective tool in the cross-examination of medical experts is the use of learned treatises. Treatises are commonly used either for impeachment or to provoke testimony of the medical expert that agrees with the propositions the treatise supports. In Missouri, the text of the treatise is not independent proof of the proposition it supports and can be used only to impeach a witness.⁶⁰ If the witness agrees with the text, however, his testimony becomes independent proof of that proposition.⁶¹

Before attempting to impeach an expert using a learned treatise, the cross-examiner must lay a foundation that the treatise is authoritative. "To be authoritative, there must be some evidence of general acceptance and accreditation of the text or treatise within the profession."⁶² This can be established by concession of the expert himself, testimony of other "experts in the field", or "judicial notice."⁶³

In the case of Gridley v. Johnson,⁶⁴ the Supreme Court of Missouri held that "[b]efore propounding a question [on cross-examination using a learned treatise] it is not necessary to ascertain whether the witness agrees with the author."⁶⁵ The Supreme Court of Missouri set forth its reasoning as follows:

We reject the proposition that the expert witness being cross-examined must first agree that the text is standard or authoritative. The practical effect of such cross-examination would be to give the witness complete control of the cross-examination. He need only say that he is not acquainted with the book or its author to prevent its use in testing his qualifications, no matter how eminent or accepted the author may be. The fewer books and authorities the witness knows about or will acknowledge and the less knowledge he has of what has been written in the field, the more difficult it will be to cross-examine him along this line. It gives him full veto power over the cross-examiner's efforts.

As we say, it is not necessary that the witness concede the text is standard or authoritative, although if the witness does so this is sufficient foundation to use the book in cross-examination. The party desiring use of the books [in cross-examination] can also establish their standing by proper voir dire examination of his own expert outside the hearing of the jury, thereby laying the foundation for their use in cross-examination at the proper time.⁶⁶

"[U]nder Missouri law it is proper to cross-examine a medical expert by framing a proposition in the exact language of the author of a medical textbook or treatise and asking the witness whether he agrees to it."⁶⁹ Failure to read the exact language from a learned treatise may result in the question not being allowed.⁷⁰ In Crain, the following series of questions were held improper because they were not confined to language out of a learned treatise:

Q. [By plaintiff's counsel]: Were you aware of the investigation dealing with the relation of Amitriptyline to the heart back in about 1965?

A. [By defendant]: No, I wasn't.

Q. Have you been brought up to date since about that? Are you familiar with that committee that was set up to explore that particular problem–

A. No, I'm not–

Q. By the basic bodies in our country–

[Defendant's counsel]: Let me object to the form of the question... [I]t assumes facts not in evidence.

THE COURT: Sustained.

Articles from periodic journals are considered less trustworthy and reliable by the courts "than texts used in the practice and teaching of medicine. Texts are subject to scrutiny from the [medical] profession and are [usually] written with less partisanship and bias."⁷³

Similar considerations do not necessarily attach to articles in periodicals and journals ... Many of the articles in such journals are mere expressions of the authors' opinions on controversial subjects .... Many of the published articles relate to experimentation and speculation and are based upon preliminary studies and are intended to invoke comment and criticism. Mere inclusion of an article in a journal, no matter how prestigious the journal may be, does not confer acceptance and accreditation of the opinions expressed by the author.⁷⁴

Because of the impact of expert medical testimony in a personal injury case, the cross-examiner must be aware of the tools that can be used for effective cross-examination. An effective cross-examination can greatly weaken the testimony of an expert medical witness and may decide the outcome of the case.

Endnotes

¹ Mr. Dysart is a former federal prosecutor. He practices in the areas of personal injury and workers' compensation for The Dysart Law Firm in St. Louis

² Ms. Zuckett an associate in medical malpractice defense at Moser & Marsalek in St. Louis She received her B.A. from Marietta College and J.D. from St. Louis University School of Law.

³ State ex rel. Lichtor v. Clark, 845 S.W.2d 55, 61-62 (Mo. App. W.D. 1992).

⁴ Landers v. Chrysler Corp., 963 S.W.2d 275, 279 (Mo. App. E.D. 1997).

⁵ "[I]t is no valid objection that the expert's opinion is upon the ultimate issue to be decided by the jury, or that it invades the province of the jury." Eagleburger v. Emerson Elec. Co., 794 S.W.2d 210, 237 (Mo. App. S.D. 1990).

⁶ Stafford v. Lyon, 413 S.W.2d 495, 498-499 (Mo. 1967).

⁷ Id. at 499. Schreibman v. Zanetti, 909 S.W.2d 692, 697 (Mo. App. W.D. 1995) (the depth and breadth of an experts' experience and knowledge are "pertinent to the weight" to be accorded their testimony).

⁸ Callahan v. Cardinal Glennon Hosp., 863 S.W.2d 852, 869 (Mo. banc 1993).

⁹ Reno v. Wakeman, 869 S.W.2d 219, 223 (Mo. App. S.D. 1993).

¹⁰ Id. at 224.

¹¹ Id. at 223-24.

¹² Id. at 223-24.

¹³ Id. at 224.

¹⁴ Weatherly v. Miskle, 655 S.W.2d 842 (Mo. App. E.D. 1983).

¹⁵ Callahan, 863 S.W.2d at 869.

¹⁶ Id.

¹⁷ 845 S.W.2d 55, 63 (Mo. App. W.D. 1992).

¹⁸ Id. at 64.

¹⁹ 863 S.W.2d at 869.

²⁰ Id.

²¹ Id.

²² Elam v. Alcolac, Inc., 765 S.W.2d 42, 199 (Mo. App. W.D. 1988).

²³ Elam v. Alcolac, Inc., 765 S.W.2d 42, 199 (Mo. App. W.D. 1988); Board of Public Bldgs. v. GMT Corp., 580 S.W.2d 519, 531 (Mo. App. E.D. 1979).

²⁴ State ex rel. Lichtor v. Clark, 845 S.W.2d. 55, 62 (Mo. App. W.D. 1992).

²⁵ Lichtor, 845 S.W.2d at 63; see also State ex rel. Creighton v. Jackson, 879 S.W.2d 639 (Mo. App. W.D. 1994), where the court held an expert engineer could be required to produce, pursuant to a subpoena duces tecum, documents including portions of his income tax returns for the past five (5) years reflecting his income received as an expert consultant or witness. The court held impeachment information could be obtained in the course of discovery. See also Willis v. Brot, 652 S.W.2d 738 (Mo. App. E.D. 1983).

²⁶ Lichtor, 845 S.W. 2d at 65.

²⁷ 13 S.W.2d 547 (Mo. 1928).

²⁸ Wilson Court, Inc. v. Teledyne Laars, 747 S.W.2d 239, 241 (Mo. App. W.D. 1988).

²⁹ See, e.g., Zarisky v. Kansas City Public Service Co., 186 S.W.2d 854 (Mo. App. _.D. 1945); Elam v. Alcolac, Inc. 765 S.W.2d 42 (Mo. App. W.D. 1988).

³⁰ Zarisky, 186 S.W.2d 854.

³¹ State ex rel. Lichtor v. Clark, 845 S.W.2d 55, 65 (Mo. App. W.D. 1992); Schuler v. St. Louis Can Co., 18 S.W.2d 42, 46 (Mo. 1929).

³² 655 S.W.2d at 844.

³³ 655 S.W.2d.

³⁴ 655 S.W.2d at 844; Schuler v. St. Louis Can Co., 18 S.W.2d 42 (Mo. 1929).

³⁵ 655 S.W.2d at 833.

³⁶ 655 S.W.2d at 844.

³⁷ Reno v. Wakeman, 869 S.W.2d 219 (Mo. App. S.D. 1993).

³⁸ Reno, 869 S.W.2d at 223

³⁹ Id.

⁴⁰ Id. at 223-224.

⁴¹ Id. at 223-224.

⁴² Id. at 224.

⁴³ Id. at 224.

⁴⁴ Id. at 224.

⁴⁵ Id. at 223.

⁴⁶ Id.

⁴⁷ Id.

⁴⁸ Lineberry v. Shull, 695 S.W.2d 132 (Mo. App. W.D. 1985).

⁴⁹ Id. at 136.

⁵⁰ Id. at 136.

⁵¹ Lineberry, 695 S.W.2d at 136; see also Wyatt v. Bearden, 842 S.W.2nd 946, 949 (Mo. App. S.D. 1992) ("[t]he test [for] whether a matter is collateral . . . is whether the party seeking to introduce it for purposes of contradiction would be entitled to prove it as part of his case").

⁵² 695 S.W.2d at 137.

⁵³ Id. at 137.

⁵⁴ Odum v. Cejas, 510 S.W.2d 218, 222 (Mo. App. S.D. 1974).

⁵⁵ Stipp v. Tsutomi Karasawa, 318 S.W.2d 172 (Mo. 1958); Sneed v. Goldsmith, 343 S.W.2d 345, 352 (Mo. App. S.D. 1961).

⁵⁶ Stafford v. Lyon, 413 S.W.2d at 499.

⁵⁷ Id. at 498-99.

⁵⁸ Klaesener v. Schnucks Markets, Inc., 498 S.W.2d 555, 559 (Mo. 1973).

⁵⁹ Id. at 559.

⁶⁰ Wilson v. ANR Freight Sys., Inc., 892 S.W.2d 658, 664 (Mo. App. W.D. 1994).

⁶¹ Berring v. Jacob, 595 S.W.2d 412 (Mo. App. E.D. 1980) (the law in Missouri provides that quotes from medical treatises, "while properly the subject of inquiry on cross-examination of a medical expert is not evidence to establish the truth of the statements made in the material unless agreed to by the witness, even if the witness acknowledges the authoritativeness of the author or publication. If the statements read are agreed to, they become evidence because the witness adopts them as his own"). Quotes from medical literature are also admissible during the direct testimony of an expert witness under the exception to the hearsay rule permitting expert witnesses to quote such material as the basis for their opinion. Stallings v. Washington Univ., 794 S.W.2d 264, 271 (Mo. App. E.D. 1990) ("rule requires that the facts or data 'be of a type reasonably relied upon by experts in a particular field'"); see also § 490.065, RSMo 1994.

⁶² Embree v. Norfolk & Western Ry. Co., 907 S.W.2d 319, 326 (Mo. App. E.D. 1995).

⁶³ Crain v. Newt Wakeman, M.D., Inc., 800 S.W.2d 105,107 (Mo. App. S.D. 1990).

⁶⁴ 476 S.W.2d 475 (Mo. 1972).

⁶⁵ Id. at 481.

⁶⁶ Id. at 481; Ball v. Burlington Northern R.R. Co., 672 S.W.2d 358, 363 (Mo. App. E.D. 1984) (an expert may be cross-examined from articles and treatises which he does not recognize, so long as some other expert has testified that the publications are authoritative).

⁶⁷ Grippe v. Momtazee, 705 S.W.2d 551, 556 (Mo. App. E.D. 1986).

⁶⁸ Embree v. Norfolk & Western Ry. Co., 907 S.W.2d 319 (Mo. App. E.D. 1995).

⁶⁹ Crain v. Newt Wakeman, M.D., Inc., 800 S.W.2d 105, 107 (Mo. App. S.D. 1990); Hemminghaus v. Ferguson, 215 S.W.2d 481, 489 (Mo. 1948).

⁷⁰ Crain v. Newt Wakeman, M.D., Inc., 800 S.W.2d 105, 107-08 (Mo. App. S.D. 1990)

⁷¹ George v. Eaton, 789 S.W.2d 56, 60 (Mo. App. W.D. 1990).

⁷² Id. at 60.

⁷³ Embree v. Norfolk and Western Ry. Co., 907 S.W.2d 319, 325 (Mo. App. E.D. 1995).

⁷⁴ Grippe v. Momtazee, 705 S.W.2d 551, 556-557 (Mo. App. E.D. 1986); Embree, 907 S.W.2d at 325.