Administrators at Maine Medical Center do not yet know whether a small group of patients was exposed to surgical equipment that also was used to treat a patient who may have a rare, pathogen-based brain disease.

Doctors learned Tuesday that biopsy results showed a patient at the hospital exhibited preliminary signs of prion disease, a rare brain condition that affects about one in a million people in the U.S. annually and is always fatal.

Although the chance of transmitting prion disease through sterilized surgical tools is exceedingly low, research shows that the standard procedure for sterilizing hospital equipment does not kill the pathogen. Staffers are examining records to determine what equipment was used in which procedures in the days between when the original patient underwent an unspecified procedure and when that patient’s test results showed a possible prion-related diagnosis.

“Hospital officials are looking at the types of surgeries, the equipment involved, and awaiting a final pathology report to determine if any patients were put at theoretical risk,” said John Porter, a spokesman for MaineHealth, the hospital’s parent network.

That’s why staff announced Wednesday that the hospital had canceled 150 elective surgeries scheduled for Wednesday and Thursday and undertaken a drastic program to re-sterilize a massive amount of surgical equipment. It took 100 staffers nearly two days working around the clock to complete the task. In addition to the regular sterilization regimen of baking the equipment under pressure in an autoclave, they washed items in a caustic bath of lye or other chemicals specifically stipulated by the U.S. Centers for Disease Control and Prevention as known to kill prions.

‘ESPECIALLY RARE CIRCUMSTANCE’

Although there are systems in place to track the instruments used in each surgery, staff erred on the side of caution in ordering the sterilization process.

Porter could not discuss any specifics about the patient, including what type of care he or she received from what hospital department, when that treatment was provided, and what type of tissue biopsy led to the potential diagnosis.

In general, however, confirming a diagnosis of prion disease typically means examining brain tissue, according to the CDC, meaning the patient at Maine Med may have undergone neurosurgical care that would give doctors the ability to harvest brain tissue to test.

While Maine Med’s equipment was being treated, necessary surgeries that could not be rescheduled were performed with equipment borrowed from other hospitals, Joel Botler, the hospital’s chief medical officer, said in a written statement.

“We want to assure all our patients that Maine Medical Center is perfectly safe from this rare infectious agent,” Botler said, while thanking the staff for working long hours to complete the sterilization process. “This is an especially rare circumstance in medicine, and the men and women here responded with the utmost professionalism and dedication to make sure we continue to provide our patients with excellent, safe, patient-centered care.”

Despite the Veterans Day holiday, a full schedule of surgeries is expected to resume Friday and Saturday, giving doctors and staff a chance to catch up on the backlog of roughly 150 procedures.

Prion diseases are rare disorders that can occur spontaneously when a protein in brain or other neurological cells malfunctions and takes on an irregular shape, spurring the same mutation when it comes into contact with other neurons, according to the CDC.

FOUR MAINE CASES IN PAST DECADE

Also known as transmissible spongiform encephalopathies, prion diseases include bovine spongiform encephalopathy (“mad cow” disease) in cattle; Creutzfeldt-Jakob disease in humans; scrapie in sheep; and chronic wasting disease in deer and elk, according to the National Institutes of Health.

Of the roughly 200 to 300 cases of prion diseases reported annually in the U.S., about 85 percent are caused by a spontaneous mutation and not any external exposure to the pathogen, according to the CDC. The remaining cases are thought to be caused by genetic predisposition passed between generations of a family.

The risk of contracting such a disease from hospital equipment is exceedingly low, according to state and national health officials. It has been decades since the last time a patient in the U.S. has contracted such a disease through contact with surgical equipment, said Ryan Maddox, an epidemiologist with the CDC in Atlanta.

There have been only four cases of prion diseases in Maine in the past decade, said Dr. Sirii Bennett, Maine’s state epidemiologist.

Only a tiny fraction of the 200 or 300 U.S. cases each year are contracted through exposure, Bennett said.

“Less than 1 percent might be caused by exposure through either contaminated tissue through either a transplant or contaminated instruments,” she said.

Test results have yet to be confirmed by the National Prion Disease Pathology Surveillance Center at Case Western Reserve University in Ohio. They could take several days to be returned, Botler said.