In virtually all personal injury cases, trial lawyers rely on the testimony of treating doctors to prove the extent of an injury and to connect cause to injury. That being said the communications between injured parties and their physicians are privileged: defense attorneys are prohibited from speaking to treating doctors or their offices regarding the nature and extent of any injury and associated causes prior to deposition.
According to the Petrillo Doctrine which prevents any ex parte communications between defense counsel and plaintiff's treaters:
"the fiduciary relationship existing between the patient and physician requires, at the very minimum, that the patient has a right to rest assured that the physician will act in good faith, while at the same time, the physician complies with court-authorized discovery. Thus, when a patient files suit, the physician should be prepared to release those records relevant to the condition placed at issue, be available to give depositions, and be prepared to testify, should he be called upon to do so....Discussion of the patient's confidences under any other circumstances, such as the ex parte conference, could be inconsistent with the duties of...the physician.... The ex parte conference involves conduct which could be violative of the duties of a fiduciary and would, therefore, be contrary to public policy favoring the fiduciary nature of the physician-patient relationship." Petrillo v. Syntex Laboratories, Inc., 148 Ill. App. 3d 581, 594-95, 499 N.E.2d 952 (1st Dist. 1986).
There are exceptions to this rule, several exceptions actually. One statutory exception to the Petrillo Doctrine is found in 735 ILCS 5/8-802. Ex parte communications between defense counsel and treating doctors is acceptable in civil actions against the physician for malpractice.