Allyson Sass’ mood heading into a two-day operation is summed up in a cartoon on her YouCaring crowd source fundraising site that reads: “‘It’s only brain surgery,’ said no one ever.”

The 24-year-old Baldwin City woman will undergo a two-day surgery Sept. 16 and 17 to remove a tumor from her acoustic nerve. The tumor, which is associated with the genetic disease neurofibromatosis type II, has quadrupled in size in the past four years and is putting pressure on her brain stem, causing her to have difficulty swallowing, bouts of dizziness and headaches.

The cartoon captures the seriousness of the surgery and Sass’ determined but hopeful approach to it.

“They told me I’d be better,” she said. “That sold me.

“Really, I’m more nervous about the rehab than the surgery. My doctors know what they are doing. The rehab, that’s more about the motivation that I will have to put out there. I’m not a very patient person.”

The surgery will be performed at Barnes Jewish Hospital in St. Louis, Mo. Allyson’s mother, Anita Sass, said it was scheduled for two days so that the surgeons would not tire during the complex procedure.

“That’s something they had not heard of,” she said of the hospital. “It took a couple of days to schedule the surgery because that’s something they don’t typically do.”

The surgery will remove about 90 percent of the tumor, Anita said. With that, her daughter’s symptoms will “plummet,” she said. A later “gamma knife” procedure will be scheduled to remove what remains of the tumor.

Mother and daughter will leave their Baldwin City home Tuesday for at least a three-week stay in St. Louis. Anita said Barnes Jewish Hospital is one of three in the United States that specializes in the treatment of the non-malignant tumor growth on nerves associated with NF2.

Allyson and her mother don’t know exactly what her post-operative schedule will be. It will include a 10-day to two-week stay in the hospital and then a transfer to a rehabilitation center when she is deemed able to perform the required three hours of daily rehabilitation.

That prolonged stay is the reason for the YouCaring funding page, said family friend Amy Adamson. Allyson will miss work as a paraprofessional at the Baldwin Elementary School Primary Center, and Anita will not have any income coming from her housecleaning business or as coordinator for an exchange student organization. The donation page can be found at www.youcaring.com/search/go?w=Allyson=Sass.

“That’s a long period of not being able to earn a paycheck,” Adamson said. “We’re looking to give them some help.”

Allyson was diagnosed with NF2 when she was 15. That wasn’t a total surprise as both her father, Chris Sass, and paternal grandfather had the genetic condition. It claimed her father’s life when Allyson was 9 years old. She first noticed symptoms while studying in Spain in spring 2012 as an undergraduate at Baker University.

Those with NF2 often require surgeries to remove tumors from the brain or spinal column and Allyson’s father, who was also a Baker graduate, had a number of surgeries before he died.

A bumper sticker on Allyson’s car identifies her as a vegan, and she and her mother have sought to control the disease through nutritional and homeopathic means. Anita credits that regimen with helping Allyson delay surgery until her 24th year.

Nonetheless, mother and daughter realize it is time for the surgery, especially when headaches recently joined Allyson’s existing symptoms. She was unable to go to work Tuesday and questioned whether she would have the strength to return before the trip to St. Louis.

A self-described introvert who “doesn’t like to leave home,” Allyson does brighten when talking about her job and the children she works with.

“I love it,” she said. “The students are very sweet, accepting and fun.”

An accomplished musician who earned a seat in state band playing clarinet while at Baldwin High School, Allyson also teaches piano lessons in the Sass home to three “dedicated” children.

She brushes aside her mother’s suggestion that she has put thoughts of her professional life on hold while dealing with her condition, but admits it’s “a great question” how she should put her Baker degree in Spanish and international relations to work.

“I have a great imagination,” she said. “I can do too many things to be able to decide. I need to condense things a little bit.”