Precluding Med Mal 'Maternal Forces' Defense
Medical malpractice cases often involve the intersection of science, medicine and law. Experts for both the plaintiff and defendant frequently testify to their opinions regarding the cause of injuries or illnesses, without citing medical or scientific literature.
Frye v. U.S., 293 F. 1013 (DC 1923) and Parker v. Mobil Oil Corp., 7 N.Y.3d 434 (2006), and their progeny, allow scientific testimony as to causation to be challenged pursuant to the court's "gatekeeper" function. The court has the power to prevent unreliable scientific testimony from potentially confusing unsuspecting jurors.
Frye is generally understood to involve an assessment of whether the scientific theory at issue has been "generally accepted" in the scientific community.
Parker focuses on the basic foundational reliability of scientific evidence. Parker requires such evidence to pass muster with regard to both general causation and specific causation.
General causation requires reliable scientific evidence that, in general, the disease or injury at issue can be caused in the manner being claimed. Specific causation requires reliable scientific evidence that the injury in the particular case at issue was, in fact, caused in the manner claimed.
For the most part, the testimony of experts concerning causation is well within the bounds of broadly accepted medical and scientific theory. It is generally based upon the expert's professional experience, and his understanding of the medicine or science. Such testimony is properly challenged through robust cross-examination, and the testimony of opposing experts, and is not the subject of a Frye or Parker challenge. See, Marsh v. Smyth, 12 A.D.3d 307 (1st Dept. 2004) (Sax, concurring).
Nonetheless, the maternal forces of labor defense, often used by the defense to explain a brachial plexus injury in a newborn (often called an Erb's palsy injury1), has recently been found to be scientifically unreliable by a number of courts in New York after a thorough exploration of all of the medical and scientific literature, and consideration of affidavits and testimony from the leading experts in the United States on this issue.
This article explores this development in the law.
The brachial plexus is a sheath of nerves which includes the lower four cervical nerve roots, and first thoracic nerve root (C5-T1) of the spine. The nerves run from the spinal cord, through the neck, and into the arm.
A brachial plexus injury is a stretch injury. It occurs when nerves within the brachial plexus are stretched beyond their anatomical capacity, or injury threshold.
Over 90 percent of birth-related brachial plexus injuries are temporary, and resolve completely within a fairly short period of time after birth. Permanent brachial plexus injuries vary in severity from mild injuries with very little permanent sequela, to severe injuries where there is obvious paralysis of the affected extremity. It is generally believed there is a direct relationship between the amount of "traction," or stretching on the nerve, and the degree of the injury.
Most birth-related brachial plexus injuries occur in the context of shoulder dystocia. Shoulder dystocia occurs when a baby's head is delivered, but the baby's shoulder is lodged on the mother's symphysis pubis. The symphysis pubis is a cartilaginous joint at the mother's pelvic outlet. During shoulder dystocia, the brachial plexus is extremely vulnerable to force being applied to the baby's head and neck by the delivering clinician. Because of this, even leading defense experts have written that lateral traction by the physician during shoulder dystocia should be "avoided at all costs."2