Dr. Cecil Hahn

The defendant obstetrician, Dr. Jackiewicz, was sued for negligence by the Woods family, alleging that his breach of standard of care in managing a twin pregnancy led to Kelsey Woods incurring cerebral palsy.

During the trial, the defendant objected to the plaintiffs' closing address, which invited the jury to find causation even if the pregnancy prolongation from amnioreduction was less than the five weeks testified to by experts.

The defendant requested an instruction that the jury *must* find against the plaintiffs on causation unless a five-week prolongation was proven.

The court declined this additional instruction, finding that there was sufficient evidence for the jury to infer causation with a shorter prolongation, consistent with the principles from *Benhaim v. St-Germain* regarding the use of statistics and inferences in medical malpractice causation.

In a medical negligence jury trial, the plaintiffs sought to introduce demonstrative aids (illustrations and charts) through their expert witness, Dr. Cecil Hahn, to explain complex medical concepts related to brain pathology, injury evolution, and statistical relationships between gestational age and neurodevelopmental outcomes.

The defendant, Dr. Allan Jackiewicz, opposed the use of these aids, arguing they were inaccurate, incomplete, unnecessary, and prejudicial.

The court, applying established legal principles for demonstrative aids, found them admissible with one minor excision to prevent misleading information, concluding that they would assist the jury in understanding complex expert evidence without being unduly prejudicial or constituting improper advocacy.

The Plaintiffs in a medical negligence action moved for leave to call four expert witnesses at trial, arguing that section 12 of the Ontario Evidence Act allowed for three experts per issue.

The court rejected this interpretation, holding that leave is required for more than three experts on all issues combined.

The motion for leave was denied, restricting the Plaintiffs to a total of three expert witnesses, citing factors such as the Defendant's objection, sufficiency of three experts for the core issues (standard of care and causation), the Defendant also calling three experts, lack of custom for more than three liability experts in medical malpractice, potential prejudice, and substantial duplication among the proposed experts.