Test for standard of pathologist’s care is not perfection: Saskatchewan Court of Queen’s Bench

In assessing whether a doctor has breached the standard of care, the court should not adopt a test of perfection but should consider whether the doctor has acted in accordance with standard recognized medical practice.

In Zoerb v Saskatoon Regional Health Authority, 2021 SKQB 7, the plaintiff visited her dentist to complain about swelling in her jaw. Her dentist diagnosed her with a severe abscess over one of her molars and referred her to an oral surgeon, who in turn submitted her case to pathology with a request to rule out ameloblastoma in the plaintiff’s right mandible. In April 1990, the defendant general pathologist, Henry Block, advised the oral surgeon that the tissue specimen was a radicular cyst, not ameloblastoma.

From 2001 to 2007, the plaintiff saw numerous medical specialists to complain about dental abscess, gingivitis and swelling in the lower right area of her jaw. In February 2007, an oral pathologist finally diagnosed a tissue specimen from the plaintiff as ameloblastoma, for which the plaintiff went through reconstructive surgery in October 2007.

In the present case, which involves crossing summary judgment applications, the parties now agree that the tissue specimen sent to Dr. Block back in 1990 was ameloblastoma, not a radicular cyst. The issue is whether Dr. Block breached the standard of care of a general pathologist at the time when he concluded that the tissue specimen from the plaintiff was a radicular cyst.

The Court of Queen’s Bench for Saskatchewan dismissed the plaintiff’s claim because Dr. Block and the Saskatoon Regional Health Authority did not breach the standard of care that they owed to the plaintiff. The court found that, back in 1990, Dr. Block may have been incorrect in his analysis, but he did everything he was supposed to do and met the standards of the day.

The plaintiff’s expert opinion came from an oral pathologist practising in Edmonton, Alberta, while the defendant’s expert opinion came from a general pathologist practising in Regina, Saskatchewan. The court found that, while both expert witnesses clearly tried to be intellectually honest, the opinion of the defendant’s expert witness was closer to the facts and gave a truer picture of reality, as lived by Dr. Block at the time he analyzed the plaintiff’s tissue specimen.

The defendant’s expert witness, who like Dr. Block also practised as a general pathologist in Regina, Saskatchewan in 1990, said that Dr. Block’s practice met the standard of care at the time. He said that ameloblastoma is an extremely rare tumour with a similar pathology as radicular cysts, so when encountering overlapping findings, pathologists tend to choose the diagnosis that is more statistically probable. He also said that Dr. Block was not negligent, was following the procedures he should have and came to a reasonable conclusion.

The plaintiff’s expert witness said that Dr. Block should have sought a second opinion because he should have known that dealing with ameloblastoma put him in a rarefied territory. However, the court noted that this witness was an oral pathologist whose training and practice came from the dental professional side, which gave him more experience with tissues and structures in the mouth and jaw areas, unlike general pathologists such as Dr. Block.

The court agreed with the reasoning stated in Dr. Block’s brief that although he misdiagnosed the tissue specimen, he went about the analysis in the right way. The standard of care should not amount to perfection. Instead, the court should refer to the circumstances of each particular patient and case at the material time, as well as the standard practice.

“In most cases, if not always, it is a complete answer to an allegation of negligence for the defendant to show that he acted in accordance with standard recognized medical practice,” said Dr. Block’s brief.