Minor impact and expert report sufficient to prove lack of causation

Causation lies at the heart of personal injury litigation. Plaintiffs must demonstrate not only that they sustained injuries, but that those injuries resulted from the defendant’s tortious conduct rather than pre-existing conditions, degenerative processes, or other intervening causes. In automobile accident cases, defendants frequently challenge causation by presenting evidence that accidents involved minimal force insufficient to cause the claimed injuries. When combined with expert medical testimony attributing plaintiff’s conditions to pre-existing degeneration, these “minor impact” defenses can defeat otherwise viable personal injury claims.

The Second Department’s decision in Frank v. Gengler provides important guidance on the evidentiary foundation necessary to establish lack of causation through minor impact evidence and defense medical opinions. The case also illustrates appellate courts’ willingness to overturn trial courts that improperly set aside jury verdicts favorable to defendants. For no-fault insurance practitioners, the causation principles articulated in Frank apply equally to first-party benefit denials based on lack of causal relationship between accidents and claimed injuries.

Case Background

Frank v Gengler, 2017 NY Slip Op 04423 (2d Dept. 2017)

Frank arose from a motor vehicle accident in which the plaintiff claimed to have sustained significant injuries requiring ongoing medical treatment. Following a trial, the jury returned a verdict in favor of the defendant, finding that the plaintiff had failed to prove that the accident was a substantial factor in causing the alleged injuries. The trial court, dissatisfied with the jury’s verdict, granted the plaintiff’s post-trial motion to set aside the verdict as against the weight of the evidence and ordered a new trial.

The defendant appealed, arguing that legally sufficient evidence supported the jury’s causation determination. At trial, the defendant had presented photographic evidence and witness testimony documenting the relatively minor nature of the collision, showing minimal vehicle damage and low-speed impact. The defendant also offered expert medical testimony from a physician who reviewed the plaintiff’s diagnostic studies and opined that the plaintiff’s symptoms and objective findings stemmed entirely from degenerative processes unrelated to any traumatic injury from the accident.

The plaintiff’s medical evidence, by contrast, attributed the claimed injuries and ongoing symptoms to the subject accident. This created competing expert opinions on the causation question, which the jury resolved in favor of the defendant’s position.

Jason Tenenbaum’s Analysis

Frank v Gengler, 2017 NY Slip Op 04423 (2d Dept. 2017)

“Here, the Supreme Court erred in determining that the jury verdict in favor of the defendant was not supported by legally sufficient evidence. The evidence presented at trial included photographic evidence and witness testimony indicating the relatively minor nature of the motor vehicle accident, and expert testimony presented by the defendant indicating that the plaintiff’s alleged injuries were solely the result of degenerative processes and were not caused by traumatic injury. Contrary to the court’s conclusion, on the basis of the evidence presented at trial, there was a valid line of reasoning by which the jury could conclude that the motor vehicle accident was not a substantial factor in causing the injuries allegedly sustained by the plaintiff (see Wilson v Philie, 107 AD3d 700, 701; Rubino v Scherrer, 68 AD3d 1090, 1092; cf. Jilani v Palmer, 83 AD3d 786, 787; see generally Imbrey v Prudential Ins. Co., 286 NY 434, 440). Accordingly, the court, upon reargument, should have adhered to its prior denial of that branch of the plaintiff’ motion which was pursuant to CPLR 4404(a) to set aside the jury verdict in favor of the defendant and for judgment as a matter of law.”

Personally, I think this case has huge repercussions. Never have I seen a court lay out such a simple road-map for getting to a determination of lack of causation between the accident and injury. It is the same thought process, regardless of whether we are litigating first-party lack of causation of third-party causation,

Legal Significance

Frank establishes a clear evidentiary framework for proving lack of causation in personal injury cases through the combination of minor impact evidence and defense medical expert testimony. The Second Department’s analysis validates a two-pronged approach: physical evidence demonstrating low-force impact combined with medical opinions attributing plaintiff’s conditions to non-traumatic etiologies. This framework applies across different procedural postures, from summary judgment motions to post-trial review of jury verdicts.

The decision’s emphasis on “valid lines of reasoning” reflects New York’s deferential standard for reviewing jury verdicts. Appellate courts do not reweigh evidence or substitute their judgment for that of juries. Rather, they ask whether sufficient evidence exists to support the verdict through any rational process of inference. When defendants present credible evidence of minor impact and expert testimony excluding traumatic causation, juries may rationally conclude that accidents did not substantially contribute to claimed injuries, even when plaintiffs offer contrary medical opinions.

Frank also reinforces that causation determinations involve questions of fact generally reserved for juries rather than courts. Competing expert opinions create credibility assessments and weight-of-evidence judgments that fall within the jury’s province. Trial courts should not disturb jury verdicts simply because the court might have weighed evidence differently or found plaintiff’s experts more persuasive. Only when verdicts lack any rational evidentiary support can courts intervene under CPLR 4404(a).

The decision has significant implications for no-fault insurance causation disputes. While no-fault cases typically resolve through summary judgment rather than jury trial, the causation principles remain identical. Insurance carriers defending claims based on lack of causal relationship must present similar evidence: accident reports, photographs, or repair estimates demonstrating minor impact combined with peer review opinions attributing claimants’ conditions to degenerative changes or pre-existing pathology rather than accident trauma.

Practical Implications

For defense counsel in personal injury and no-fault cases, Frank provides a validated template for establishing lack of causation. Attorneys should gather comprehensive physical evidence of accident severity, including photographs from multiple angles, vehicle damage estimates, impact speed calculations, and witness observations about post-accident vehicle condition. This evidence, when combined with properly qualified medical expert opinions excluding traumatic etiology, creates a complete causation defense.

Defense medical experts should provide detailed analysis explaining why claimed injuries do not stem from accident trauma. Effective expert opinions identify specific degenerative findings on diagnostic studies, correlate those findings with expected age-related changes, note absence of acute traumatic indicators, and explain inconsistencies between accident mechanism and injury patterns. Generic conclusory statements about pre-existing conditions lack the analytical depth necessary to withstand scrutiny on summary judgment or at trial.

Plaintiff’s counsel must recognize that minor impact evidence, while not dispositive, creates significant hurdles for proving causation. When photographic evidence shows minimal damage, plaintiffs need particularly strong medical testimony explaining how low-force impacts nonetheless caused their injuries. Biomechanical experts may be necessary to rebut assumptions that minor damage correlates with minor forces. Additionally, plaintiffs should emphasize any immediate post-accident symptoms, prompt medical treatment, and absence of prior complaints to demonstrate that conditions manifested only after the subject accident.

For no-fault insurance carriers, Frank reinforces the viability of lack of causation defenses in appropriate cases. Carriers should implement protocols for identifying cases where minor impact and degenerative findings support causation challenges. Early referral for independent medical examinations focused on causation issues allows carriers to develop peer review opinions while claims remain within administrative denial windows. However, carriers must ensure peer reviewers address causation specifically rather than offering only medical necessity opinions.

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