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Tag: Biomechanical Engineers

More on BC Injury Claims and Biomechanical Engineering Evidence

Written by admin on . Posted in Civil Procedure, Uncategorized. 131 Comments on More on BC Injury Claims and Biomechanical Engineering Evidence


Further to my recent post on this topic, the evidence of biomechanical engineers is becoming more common in BC injury lawsuits.
Biomechanics is the study of forces applied to biological tissue and the injuries that can result from such forces.  In litigation it is easy to imagine the use such expert opinion evidence can be put to in proving causation of injuries.
Biomechanics is a relatively new scientific field.  Courts are generally conservative and can be slow to accept ‘novel‘ scientific evidence.  Despite judicial conservatism, biomechanical evidence does appear to be gaining acceptance by BC Courts as demonstrated in reasons for judgment released today.
In today’s case (More v. Bauer) the Plaintiff suffered a severe brain injury while playing hockey.  The Plaintiff claimed his helmet was negligently designed and sued the manufacturers of the helmet.  In support of his claim he called a biomechanical engineer who gave evidence in the field of biomechanics and the biomechanics of safety standards.
The Defendants did not challenge his qualifications to give this evidence, however, at the conclusion of the expert’s testimony the Defendants brought a motion to rule the testimony inadmissible arguing that the expert’s “underlying methodology and science are so flawed that the evidence (does not meet the legal test for admissibility)” and that the expert was “biased and purposely misled the court to assist the plaintiff“.
Mr. Justice Macaulay rejected the motion and concluded that the evidence was in fact admissible.  In doing so the Court recognized biomechanics as an “accepted area of scientific and academic expertise“.  The Court reasoned as follows:
[1] Dr. Stalnaker has a Ph.D. in theoretical and applied mechanics. Through much of his lengthy career, he has worked in the branch field of biomechanics. He also has practical experience in standards development for certification purposes although not specifically with regard to hockey helmet standards. Biomechanics involves the study of body kinematics ? the forces applied to biological tissue and the injuries that can result. The plaintiffs sought to qualify Dr. Stalnaker as an expert in biomechanics and the biomechanics of safety standards…

[12] Mohan sets out the current approach to the admissibility of expert evidence. Mr. Justice Sopinka outlines the following criteria for the admissibility of opinion evidence:

(1)      the evidence must be relevant to some issue in the case;

(2)      the evidence must be necessary to assist the trier of fact;

(3)      the evidence must not contravene an exclusionary rule; and

(4)      the witness must be a properly qualified expert.

[15] Assessing reliability includes determining whether the science or technique the witness uses to reach a conclusion is “novel”. Novel science will be subject to a stricter level of scrutiny than theories or techniques that are more generally accepted…

[23] To conclude, in assessing reliability when exercising my gatekeeper role, I must determine whether the approach the impugned expert takes is novel. If Dr. Stalnaker is relying on a novel theory or technique, I should exercise a higher level of scrutiny when examining reliability, in order to prevent the trial becoming “a medical or scientific convention with an exchange of highly speculative points of view” (R. v. J.E.T. at para. 77).

[24] In assessing reliability, I may find the Daubert factors helpful, but need not apply them too strictly. The purpose of applying the factors is to determine the degree of uncertainty present in the impugned expert’s analysis. The question is whether “the degree of uncertainty is unacceptable given the likely effect upon the trial process and the trier of fact. The level of acceptable uncertainty may depend upon the purpose for which the evidence is tendered and the use made of the evidence by other experts” (Wolfin at para. 20). Both the mode of trial and the importance of the evidence to making a final determination of the matter are factors to consider. If a theory or technique is implausible it will not be admitted.

[25] I remain persuaded that biomechanics is a recognized and accepted area of scientific and academic expertise. I am satisfied that Dr. Stalnaker is qualified to give opinion evidence in the area of biomechanics including in relation to safety standards. Opinion evidence is necessary to assist me in drawing appropriate inferences of fact.

Expert Evidence – Doctors, Biomechanical Engineers and Force Necessary to Cause Injury

Written by admin on . Posted in Civil Procedure, Uncategorized.


When a personal injury claim is advanced the Plaintiff has the burden to prove what injuries they suffered and that these were caused (or materially contributed to) by the trauma in question.  In proving a case it is common for a Plaintiff to obtain expert opinion evidence from medical doctors to address issues such as diagnosis of injury, prognosis, treatment needs, disability and causation.
One tactic used by personal injury lawyers is to try and limit the scope of the opposing sides expert witness’ opinions.  If a witness wanders outside of their area of expertise then those portions of their opinion become inadmissible.
When addressing the issue of causation a developing area of BC Injury Law is whether a physician can give opinion evidence with respect to the forces necessary to cause a specific injury.  Some argue that this is outside of a medical doctors training and is better left to biomechanical engineers.  Reasons for judgement were released today by the BC Supreme Court, Vancouver Registry, dealing with such an argument.
In today’s case (Pham-Fraser v. Smith) the Plaintiff sustained numerous injuries in a 2006 BC car crash.  The Plaintiff’s vehicle was struck at an intersection when the Defendant entered against a red light.  The issue of fault was admitted focusing the trial on the issue of damages.
In support of her case the Plaintiff called numerous physicians to give expert opinion evidence.  One of these witnesses was Dr. Brian Hunt, a neurological surgeon.  He provided the opinion that the “accident created sufficient deceleration forces to produce damage to (the plaintiff’s) L5 vertebra through abnormal axial-loading but that a biomechanical engineer (would need to) confirm this probability“.
The Defence lawyer argued that Dr. Hunt was simply not qualified to give this opinion and that this opinion was inadmissible.  Mr. Justice Greyell rejected this submission and provided the following useful analysis:

[50] Mr. Killas argued certain aspects of the expert evidence called by the plaintiff were inadmissible and that other expert opinion evidence should be given little or no weight.  In particular the defendants argued I should give little or no weight to Dr. Hunt’s opinion the accident created sufficient forces to produce damage to the L5 vertebral body through abnormal axial loading.  Mr. Killas pointed out Dr. Hunt then qualified this opinion with this remark:  “However a biomechanical engineer will need to confirm this probability”.  Mr. Killas noted Dr. Hunt had not done an investigation into the circumstances of the accident (vehicle speed, etc.) to make his opinion.

[51] Mr. Killas also argued Dr. Hunt’s diagnosis that the plaintiff sustained a brain dysfunction secondary to brain injury was simply based on the reading of Dr. Longridge’s medical report and on an unproven assumption the plaintiff had a lack of awareness of the circumstances of the motor vehicle accident.  Mr. Killas also argued Dr. Hunt’s opinion the plaintiff probably suffered abnormal axial loading on her spinal column during the accident was qualified by Dr. Hunt when he said in his report that “a biomechanical engineer will need to confirm this probability”.

[52] I accept Dr. Hunt’s opinion on both these issues.  There was evidence concerning the plaintiff’s limited recollection of what happened following the accident and I accept Dr. Hunt, given his qualifications and special experience, was well able to offer the opinions he did.

[53] I have ascribed as much weight to Dr. Hunt’s opinion concerning the cause of the plaintiff’s lower back injury as I have on the opinions of the other specialists who testified, including Dr. Schweigel.  Dr. Hunt’s expertise (and that of the others) has been gained through many years treating patients who have been involved in motor vehicle accidents.  He is well qualified to offer the opinion he did.  The fact Dr. Hunt was prepared to defer to the opinion of a biomechanical engineer does not, in my view detract from his expertise in offering his opinion to the court on the cause of the plaintiff’s lumbar spine injury.  I similarly find that the evidence of Dr. Hartzell concerning the forces applied to the plaintiff’s lower spine during the accident is helpful to the court and hence admissible, given his experience and qualifications.  Both Dr. Hunt and Dr. Hartzell, through their long and distinguished medical practices have had experience with persons with spinal injuries.