A Kaiser Permanente neurosurgeon removed a healthy part of a patient’s brain instead of a tumor, causing permanent brain damage that left the man unable to read or write, according to a lawsuit filed Friday in Multnomah County Circuit Court.

Dane Brandon Zimmer, 46, is seeking $25 million. The lawsuit, filed on Zimmer’s behalf by a conservator, alleges that a 2018 surgery at Kaiser Sunnyside Hospital left Zimmer with permanent brain damage. Kaiser Permanente didn’t immediately respond to a request for comment.

Zimmer, then 44, went to the emergency room at Kaiser Permanente Sunnyside Medical Center in February 2018, suffering from headaches, confusion and agitation, the lawsuit says. A CT scan found a large mass in his brain and a neurosurgeon, Charles Wrobel, diagnosed it as a hemangioblastoma, the suit says.

The slow-growing, benign tumor was causing an obstruction in Zimmer’s brain, the suit says, leading to a decision to perform surgery to remove it.

After his morning surgery, Zimmer couldn’t communicate with recovery nurses, who described his speech as “word salad,” the lawsuit says.

Another CT scan showed the surgery had been performed in the wrong location and the mass was still present, the lawsuit says. No trace of the tumor was found in pathology testing of the tissue that had been removed, Zimmer’s suit says.

The tissue had come from a part of Zimmer’s cerebrum that helps with language development instead of from his cerebellum, his lawsuit alleges.

Wrobel performed another surgery on Zimmer that evening, with the assistance of another doctor, the suit says, successfully removing the mass.

Zimmer, who had suffered a brain injury at 19, had been able to care for himself and live independently before the surgeries, his suit says, the result of extensive rehab. But after the surgery, the suit says he could not read three letter words out loud and wrote words like “cat” and “dog” as “cath” and “doag.”

Zimmer is represented by Portland attorney Robert Beatty-Walters. The suit seeks $100,000 for medical expenses, $725,000 for lifetime medical care, lifetime living expenses of $6.1 million and economic damages of $18 million.

— Rob Davis

rdavis@oregonian.com

503.294.7657; @robwdavis

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