Children’s boutique owner Rachel Uchitel, who is otherwise known for the affair she had with professional golfer Tiger Woods, has brain surgery scheduled for Sept. 22, according to her Instagram.

Uchitel was recently diagnosed with Arnold–Chiari (kee-AR-ee) malformation, or Chiari malformation for short. It’s a congenital birth defect that has adverse effects on the brain and spinal cord connection, Columbia University Medical Center reported. There are four types of malformations, but type 1, which is also the type Uchitel has been diagnosed with, is the most common.

Columbia said type 1 malformation can go unnoticed into adulthood — patients don’t know they’re affected until they start showing symptoms, such as headaches, stiffness or pain in the neck or back of the head, decreased muscle strength, even breathing problems. Uchitel herself reported experiencing frequent “headaches, awful back aches, ‘brain fog,’ short term memory loss,” as well as tingling sensations in her hands and feet.

But the worst part for Uchitel, she said, has been the fact she’s unknowingly been living with this rare neurological disorder. The American Association of Neurological Surgeons cited the prevalence of Chiari is “slightly less” than one in 1,000, with most cases being asymptomatic.

“The worst part about Chiari is that it's an invisible disease,” Uchitel wrote on Instagram. “On the outside, we may look like we don't suffer but on the inside it feels like we are crumbling.”

It was during a recent MRI for Uchitel’s frequent headaches and back pain that her doctor discovered the type 1 malformation, thus prompting her to schedule surgery. The National Institute of Neurological Disorders and Stroke (NINDS), a component of the National Institutes of Health, explained that "surgery is the only treatment available to correct functional disturbances or halt the progression of damage to the central nervous system." Most individuals will see a reduction in symptoms, but as MSN reported, there’s still a 50 percent chance that symptoms will persist post-surgery. In which case, the NINDS said sometimes patients will require more than one surgery to treat the condition.

Surgeons will make an incision in the back of Uchitel’s head and remove a small portion of the bottom of her skull and maybe spinal column in order to correct the irregular, pain-inducing structure. Additional brain tissue may be added to the dura, or the covering of the brain, in order to create more space for the flow of cerebrospinal fluid.

While surgery is poised as the best treatment, it may not be best for every single patient. Columbia reported a patients’ age, overall health, and medical history will factor into whether or not they should elect the treatment. Columbia added the extent of a patient’s condition, the type of condition, and a patient’s tolerance for medications and therapies are also taken into consideration.

Coincidentally, September is Chiari Awareness Month. Given that most cases are asymptomatic, often discovered by accident, patients like Uchitel are eager to get the word out about this rare disease. The NINDS is currently working hard to learn and better understand the genetic factors that cause this painful malformation in the first place.