Tiffany Johnson and her husband, JJ, are avid cruisers -- self-described "vacation junkies." In June 2017, the two left their home in Charlotte, North Carolina, and embarked on a relaxing cruise in the Caribbean.
On their final day, the Johnsons chartered a snorkel expedition in the Bahamas.
They took off in a small boat with another couple to a spot 10 minutes from Paradise Island.
Thirty minutes into the snorkeling excursion, Johnson bumped into something.
"I was just staring at the fish, and I felt a tug on my arm," Johnson said.
"I remember even just thinking 'Oh, what did I bump into?' And then when I turned, I was face-to-face with the shark."
The fight for her life
All she could see was the shark's black, beady eyes staring her down, then darting around. It was such a shock, it took a while for her to realize her entire arm was in the shark's mouth.
"It was just this weird, eerie presence," she recalled. "Fear just took over."
Instinctively, Johnson tried to pull her arm out of its mouth, and that's when it clenched down right below her elbow.
"I remember hearing the sound of my screaming through the snorkel tube," she said.
"My body wanted to give up. I was seeing almost like a movie reel of my kids," said Johnson, a mother of three. "And I remember thinking, 'No, we are not going there.' And that's when the strength in the Lord just rose up from inside of me and gave me the strength to fight back."
Thrashing, pulling, praying, Johnson finally won the battle, but when she ultimately yanked her right arm free, half was gone, from the elbow down.
"It was a mangled stump. And I remember even thinking right away, like, 'Oh my gosh, my arm's gone.' But I didn't feel any pain," she said.
The attack lasted no longer than a few minutes, she thought. The Johnsons later learned it was surprising that she survived at all.
"Most people die from sharks pulling them down and drowning them," she said, but Johnson was at surface level the entire time, breathing out of her snorkel tube.
Back to the boat
Johnson yelled out as she swam back with her left arm.
Her husband, who had gotten out of the water earlier, dove in to help her back to the boat.
Once on deck, Johnson was calm. She said she felt a peace beyond anything she could ever express.
"My husband was frantic, you know, just in sheer terror, and the captain's the same way, trying to grab the anchor," she said.
She had such a sound mind that she instructed her husband to grab their beach towel -- the only available option -- to stop the bleeding.
"And then I laid my head down and I closed my eyes because in front of me I had literally sprayed blood everywhere. And I began to pray," she said.
They stopped at Paradise Island, the closest shoreline. But they couldn't help with such a severe injury. They had to return to the main port in Nassau.
"When the ambulance arrived (at the port in Nassau) and they started wrapping my arm, that's the first time I felt pain. So, 45 minutes maybe without pain, which is just a miracle," Johnson said.
She had her first surgery in Nassau, but the hospital there could only do so much. She needed to return to the United States for more intensive surgery.
There was a problem: They didn't have their passports, since they didn't need them while cruising, and an emergency passport would take too long.
"We had the minister of tourism in the Bahamas involved, the embassy involved, Customs involved. They were all trying to figure out a way to get us back to the US," Johnson said.
Johnson called her pastor back home in Charlotte. He had connections with a private jet company in the Bahamas.
She was evacuated off the island the next day and taken home to Charlotte.
Making prosthetics more human
Once Johnson arrived in Charlotte, she was placed under the care of orthopedic surgeons, Drs. Bryan Loeffler and Glenn Gaston. They're two of the surgeons pioneering an innovative procedure called targeted muscle reinnervation, or TMR, developed by Dr. Todd Kuiken in 2002.
The procedure has been the front line in the effort to improve the interface between humans and technology. The goal is simple: Give hope -- and control -- back to upper-limb amputees.
TMR enables the user's mind to communicate with artificial limbs via prosthetics that connect to the nervous system.
When most people raise a thumb, the brain sends a signal down the spinal cord, through a network of nerves that go down the forearm and into the muscles of the thumb, telling it to lift.
"When the hand (is) lost, you still have that same signal that can be sent down, but it doesn't have a target anymore," Loeffler said.
With TMR, the surgeons take residual nerves that previously controlled the amputated limb and rewire them into the remaining part of the limb. It essentially gives that signal a target in a new muscle.
"The signal that's going from the brain, now it doesn't have a dead end, it has a muscle, and it will cause it to contract. When the muscle contracts, it generates an electrical signal that is detected by a sensor that's on the skin, and that signal is transduced into a prosthetic to allow the thumb function to occur," Loeffler said.
The intuitive, thought-controlled bionic arm has come a long way since its inception.
According to Gaston, within an hour of training, many patients are able to perform all the functions that the prosthetic allows. In the past, that would've taken months of training.
"They literally just have to think 'close my hand,' and they close their (prosthetic) hand," Gaston said.
It also has another benefit for amputees -- it greatly reduces or eliminates neuroma pain, also known as phantom pain, which is the experience of pain in the lost limb.
Loeffler said the nerves that are severed from the amputation act like exposed live wires, but with TMR, they are now a closed circuit, since they've been assigned a purpose.
According to multiple studies over the past decade, TMR offers a novel solution for post-amputation neuroma pain. For that benefit alone, both doctors say the procedure is worthwhile and can be performed at any time, even years after an amputation.
For Johnson, it has been a tough journey since the attack. She has relearned how to perform once-simple tasks, such as eating, writing and cooking.
She's adapting to life with one arm, and so is her family. But there was another helping hand on the way.
Getting a 'smart arm'
Johnson smiles and lights up the waiting room at OrthoCarolina Reconstructive Center for Lost Limbs, which is run by Loeffler and Gaston.
Here, she's a poster child for positivity. "She has been an incredible person through it all and I think her drive and her spirit to get through everything is really exemplary. And she's rubbed off on a lot of our other patients," Gaston said.
Johnson is a fast learner. She signs her medical documents with her left hand fairly well for a new lefty and, as she quips, in handwriting better than her husband's.
Now it's time for more learning. On this day, she is receiving her first mind-controlled "smart arm."
Electrodes are placed all around Johnson's right elbow, and the mechanical prosthesis is placed on. Within minutes, she's bending, grasping and pointing with the bionic arm.
All of these actions originate from the simple intent to do so. It's an incredible moment for both the patient and the doctors.
"The real unique challenge with Tiffany was the very short residual limb that we had to work with. We had to be fairly creative with which nerves we re-routed to the few muscles remaining," Gaston said.
Johnson is excited to tie her hair up in a ponytail, and cook with both hands again.
The journey ahead
During the past 15 years, TMR has continued to bridge the gap between human and machine.
"The pace of technology, particularly in this area, is mind boggling. It seems like every few months something else is coming along. I think, to some degree, the surgeries outpace the technology," Gaston said.
Right now the research lies in improving functioning of intuitive limbs, as well as implementing sensation into them.
When pressure is detected by the prosthesis, Loeffler said that can send a signal to their brain telling them it is touching something.
"The ability to touch and perceive things without looking at them is what makes a hand a hand. We're going to see, in the future, that these prosthetics are going to become more and more life-like," he said.
Above all, Johnson credits her faith for keeping her steady.
"A couple of days after the attack, I started reading Psalm 18 and I couldn't keep it together ... where it says 'the grave wrapped its robe around me. Death itself stared me in the face.' That's exactly what happened; I was staring face to face with that shark," she said.
"And then later, 'He reached down from heaven and rescued me; he drew me out of deep waters.' I was just in awe of reading this. I was just thinking, oh my God, this is my story."