However, a year ago her life changed forever.
"I spent my 30th anniversary in this hospital bed," Niedziela said.
The nurse leader who once oversaw spinal care at the hospital became a patient herself after being struck by a falling tree while traveling in Costa Rica.
Niedziela's spinal cord was crushed and is now paralyzed.
"This is a tragic accident that happened to me but it's outside of my control," she said. "I can't look back on the calendar."
On Thursday, Niedziela returned to Mission Hospital one last time in her role as executive director of acute care services.
She made her final rounds and said goodbye to doctors and nurses.
"I just know my coworkers are just amazing people," Niedziela said.
Deanne's colleagues like Cherie Fox said retirement brings closure to an amazing career.
"To have taken care of patients and to led this spine institute and now to have to be a patient participating in that is really just an extraordinary triumph of courage and strength," Fox said. "She absolutely is a driving force for many of us nurses on how to overcome, how to adapt and how to really be that guiding principle for a lot of us."
Niedziela is focused on her recovery and becoming more independent.
A GoFundMe page has been set up to help her achieve that goal.
She said she wouldn't be able to tackle this new chapter of her life without those who she's worked so closely with for the last three decades.
"I'm just so blessed to have so many wonderful people in my life," Niedziela said. "You know now we can live anywhere and I'm like I don't want to leave because they're my family. They're just my family."