By Wayne Drash, CNN

(CNN) -- Cara Pressman sobbed in the big red chair in her living room. The 15-year-old tried to absorb the devastating news relayed by her parents: that their insurance company, Aetna, denied her for a minimally invasive brain surgery that could end the seizures that have haunted her since she was 9 years old.

"When my parents told me, I went kind of blank and started crying," she said. "I cried for like an hour."

Her friends had been lined up to visit her in the hospital for the surgery three days away, on Monday, October 23. Between tears, she texted them that the whole thing was off.

It was supposed to be a joyous weekend. Cara's grandparents had come to town to celebrate their 90th birthdays, a jubilant party with more than 100 family and friends crowding her home. The party did go on -- just with a lot more stress.

Cara had multiple complex partial seizures that weekend. When the seizures strike, her body gets cold and shakes, and she zones out for anywhere from 20 seconds to two minutes, typically still aware of her surroundings. Her seizures can be triggered by stress, by being happy, by exerting herself -- almost anything. "It's like having a nightmare but while you're awake," she said.

In the six weeks since the denial, Cara has had more than two dozen seizures affecting her everyday life. Her message to Aetna is blunt: "Considering they're denying me getting surgery and stopping this thing that's wrong with my brain, I would probably just say, 'Screw you.' ''

Aetna: We're looking out for what's best for patients

The Pressman family and, separately, Jennifer Rittereiser, a 44-year-old mom who has struggled with seizures since she was 10, approached CNN in recent weeks after they were both denied, by Aetna, for laser ablation surgery, a minimally invasive procedure in which a thin laser is used to heat and destroy lesions in the brain where the seizures are originating. Aetna is the third-largest health insurance provider in the country, providing medical coverage to 23.1 million people.

Neurologists consider laser ablation, which is performed through a small hole in the skull, to be safer and more precise than traditional brain surgery, where the top portion of the skull is removed in order for doctors to operate. The procedure is less daunting for the patient and parents who make decisions for their children: No one likes the idea of a skull opened and a chunk of brain removed.

In denying Cara her surgery, Aetna said it considers laser ablation surgery "experimental and investigational for the treatment of epilepsy because the effectiveness of this approach has not been established."

"Clinical studies have not proven that this procedures effective for treatment of the member's condition," Aetna wrote in its rejection letter.

The insurance company did approve her for the more invasive and more expensive open brain surgery, called a temporal lobectomy, even though her medical team never sought approval for the procedure.

The laser surgery is approved by the Food and Drug Administration and is widely recognized within the epilepsy community as an effective treatment alternative to open brain surgery, especially when the location of seizure activity can be pinpointed to a specific part of the brain.

Dr. Jamie Van Gompel, a neurosurgeon at the Mayo Clinic, disputes Aetna's assessment. He is not involved in Cara's care nor Rittereiser's treatment, but he said Aetna's assessment is wrong.

"I would not call it experimental at all," said Van Gompel, who is leading a clinical trial on the surgery at Mayo as part of a larger national study. "It's definitely not an experimental procedure. There've been thousands of patients treated with it. It's FDA-approved. There's a lot of data out there to suggest it's effective for epilepsy."

Van Gompel said a temporal lobectomy carries a much higher risk of serious complications, including the possibility of death. "It's a big jump to go to a big invasive procedure," he said.

Recovery time after open brain surgery can range from six to 12 weeks. By contrast, a patient who undergoes laser ablation can be back to work or at school in less than two weeks. The pain from laser surgery is much less, and extreme headaches are fewer than with open brain surgery, Van Gompel said.

While laser ablation has not yet undergone large randomized controlled trials, Van Gompel said existing data shows it's effective more than 50% of the time. He hopes the current clinical trial will show a success rate of 60% to 70% or better in epilepsy patients. Temporal lobectomies, he said, have a slightly better rate, of more than 70%.

Pressed by CNN for a better explanation on its denial, Aetna stood by its rejection for Cara and Rittereiser, saying it was in the best interest of the patients. But the language was softened slightly.

"Clinical effectiveness and our members' safety are the primary criteria we use in determining whether a treatment or service is medically necessary," Aetna said. "There is currently a limited amount of evidence-based, clinical studies related to laser ablation surgery. As noted by the Epilepsy Foundation, only studies with a very small number of participants have been used to report the effectiveness of this procedure. We consistently evaluate any new studies or additional evidence when developing our clinical policy bulletins, and will continue to do so for this procedure."

Contacted for reaction, the Epilepsy Foundation strongly objected to Aetna's remarks, saying the insurance company took its information out of context. Laser ablation surgery "has emerged as a new minimally invasive surgical option that is best suited for patients with symptomatic localization-related epilepsy," said Dr. Jacqueline French, the chief science officer with the Epilepsy Foundation.

"This technology is much less invasive than the alternative, which involves removing a sizeable piece of brain, at a substantially higher monetary and personal cost," French said. "This path should be available, if the treating epilepsy physician has recommended it, without delay or barriers."

Phil Gattone, the president and CEO of the Epilepsy Foundation, said insurance denials and other barriers to treatment have become a common battle for thousands of Americans with seizure disorders.

Gattone knows first-hand the pain of what Cara's parents are going through. His own son began having seizures when he was 4 and underwent brain surgery in the early 1990s. "It was extremely challenging for our family to make a decision to remove part of our child's skull and brain for a surgery that we hoped would end the devastation of seizures that were stopping his development," Gattone said. "We took this leap of faith and made the decision, and it worked out the best for him."

But he added that he and his wife wished laser ablation surgery had been available back then. Laser ablation was approved by the FDA nine years ago. "I know that my wife and I would've found much more comfort if we had had (laser ablation) as an option," he said.

Gattone said people with seizures, their caregivers and their doctors should not be "spending critical time in the midst of a health-care crisis, filing paperwork, making appeals or otherwise going through the motions of administrative paperwork" trying to get approval for a life-changing operation.

"The Epilepsy Foundation can understand no reason why an insurance company would place any barrier to delay a treatment that may save an individual's life, promote the development of the young child's brain or bring about seizure control," Gattone said.

Mom who crashed with kid in car gets denied

Jennifer Rittereiser lost consciousness behind the wheel of her silver SUV while driving with her 7-year-old son, Robert, in April. Her SUV rammed into a car in front of her and struck it again before veering into oncoming traffic. Her vehicle careened down an embankment, flipped over and came to rest on its side amid a tangle of brush. She narrowly missed slamming into a guardrail and several trees.

Mom and son somehow managed to walk free unharmed.

"People were amazed," she said. "They had a helicopter on the way, actually. I am extremely fortunate just from that sense."

Rittereiser has battled seizures since she was 10 and has been able to function with an array of medications in the three decades since. For much of her life, she could tell when the seizures might come.

These weren't like the seizures depicted in Hollywood movies; she wouldn't fall to the ground and writhe. She would zone out for a spell. She could understand people and could still function but couldn't speak back -- or if she did, her words were garbled.

As an executive in the health care industry, Rittereiser has fallen asleep during meetings. When she senses a seizure coming, she rushes to the bathroom to hide until they go away. One time, she says she urinated on herself at her desk without realizing it.

Rittereiser had a crash in 2014 in which she rear-ended a car after she had a seizure. No one was hurt in that crash, but she stopped driving for more than a year. Her medications were tweaked, and her seizures were largely kept in check, until the crash this April.

She was soon evaluated by an array of doctors and recommended for laser ablation surgery. After 34 years of struggling with seizures, she thought her ordeal might finally come to an end. Surgery was set for June 16.

But in late May, Aetna denied the surgery. She fought Aetna's decision through a lengthy appeals process. Aetna refused to budge.

"It's just not right," Rittereiser said.

She said she recently went to Aetna's website to look up the company's values. She felt nauseated. "Everything in their core values is not being shown in the way I'm being treated. They're talking about promoting wellness and health and 'being by your side.' "

She paused, contemplating the company's "by your side" catchphrase, saying it's "the most ridiculous thing, because they are the biggest barrier to my success and my well-being going forward.

"It drives me crazy."

Dad: 'You get so angry'

Julie Pressman stood near an elevator at her doctor's office when word came that Cara's surgery had been denied. The mom fell to the floor and wept.

She called Cara's father, Robert. He was at the airport picking up his 90-year-old parents for their birthday party. Mom and Dad rallied for their daughter and gathered strength to break the news. That's when Cara sat in the red chair, crying inconsolably.

"Telling Cara was horrible," her mom said. "Horrible."

"It's just so frustrating for us to know there's a solution out there -- a way to fix our daughter -- and some bureaucratic machine is preventing this from happening," Robert Pressman said. "You get so angry, but you don't know who to take it out on, because there's no particular person that's doing it. It's this big bureaucracy that's preventing this from happening."

Julie and Robert said the most beautiful day of their lives came on August 20, 2002, when Cara popped into the world and met her 2-year-old sister, Lindsey, for the first time. "That was the day we became a family," Julie said. "Our love for those girls is amazing. How we got this lucky is beyond us."

But that luck has been tested. When Cara was 9, she'd complained of extreme headaches for much of the day one evening, and then in the middle of the night, she began seizing uncontrollably. The family had two black Labradors that had gone to her room and barked like crazy to alert her parents. Cara had bitten her tongue, and blood was running down her face when they got to the room.

It was a terrifying scene. She was rushed off in an ambulance and underwent a battery of tests. Mom, Dad and Cara never thought they'd still be battling seizures six years later -- let alone an insurance company. She's had seizures on the soccer field, during softball games, on stage during plays, in the classroom. Almost everywhere.

How does she envision a life without seizures?

"I don't know," she said. "I've never had a life without seizures."

"You will. You will," her dad told her.

"I just don't know when," she responded.

Mom: "It will happen, kiddo."

Her mother calls Cara a feisty, petite powerhouse with big marble eyes and long eyelashes and a funny wit to match. She's a naturally gifted athlete, singer and dancer, but her parents feel that her seizures have kept her from reaching her full potential.

They long for the day when the seizures are gone. The parents said they have paid $24,000 for insurance with Aetna this year. They're determined to get Cara laser ablation surgery with or without the insurance company's help. They will appeal Aetna's latest rejection -- but they're not optimistic.

In preparation, they've begun exploring raiding their retirement funds to pay the $300,000 out of pocket. "Cara is worth every penny, but man," her mom said. " 'Screw Aetna,' indeed, to quote my kid."