Tiffany Johnson: TMR Was the Right Choice After Shark Attack

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By Betta Ferrendelli

Tiffany Johnson experienced an event few others have, and she has lived to share her story.


Johnson, 33, was attacked by a shark while snorkeling in the Bahamas on June 2, 2017. She was treading water exploring a reef when something pulled on her right arm. "I felt a tug and I thought, ‘What did I bump into?' And when I turned to look, I was face-to-face with a shark," Johnson says.


She expected the worst from the attack, which lasted only a few minutes. She thought the shark would drag her underwater and she would drown. "There was a lot of thrashing and struggling, but I never swallowed any salt water," says Johnson, who stayed on the surface breathing through her snorkel while maintaining eye contact with the shark through her face mask. The shark's initial bite was about three inches below her shoulder but didn't sever her arm. The shark, which she was later told was likely a tiger shark, bit her again just below her elbow. She says she could hear herself screaming through her snorkel as she tried to pull her arm from the shark's jaws. She freed herself, but there was nothing left below her elbow. "My arm was completely gone," she says.


Johnson underwent emergency five-hour surgery in the Bahamas, where physicians treated the wound to prevent infection. She came out of surgery in critical but stable condition. She remembers the pain. "It was excruciating," she says.


She was transferred home to Charlotte, North Carolina, the following morning and underwent a second surgery to debride and clean her arm to minimize the risk of infection.


The Best Choice

Targeted muscle reinnervation (TMR) is a surgical procedure that is used to lessen neuroma pain and to improve prosthetic control for those who have upper-arm amputations.


Glenn Gaston, MD, and Bryan Loeffler, MD, are considered pioneers in the innovative procedure that was developed by Todd Kuiken, MD, PhD, and Gregory Dumanian, MD. Johnson met Gaston and Loeffler in the hospital following her second surgery.


It was the physicians' suggestion that Johnson have TMR. "It is our practice to perform TMR on all patients with traumatic upper-extremity amputations involving the hand or arm in an effort to minimize the long-term pain that these patients can experience," Gaston says.

One reason acute TMR (TMR done soon after an amputation occurs) facilitates accelerated recovery is that soft tissue swelling from the surgery and initial injury decreases concurrently as opposed to repeated recoveries after undergoing multiple surgeries, Gaston says. Another strategy to speed recovery is to perform the nerve transfers close to or directly into the muscles targeted for "switch innervation," Gaston says. "This allows the nerve endings to grow directly into their new muscle and begin controlling it for contraction. This nerve growth occurs simultaneously with the soft tissue recovery following amputation."


Johnson had the TMR procedure as an outpatient one week after the shark attack. "We routinely perform this procedure as an outpatient basis," Gaston says. "This is due, in part, to the fact that Dr. Loeffler and I work as a team when doing these procedures, which shortens the operative time considerably."


The surgery made sense, says Johnson, the mother of three young children. "The benefits of the surgery beyond setting me up for a myoelectric prosthesis was a no-brainer. I was definitely willing to go through an additional surgery not to be in pain for the rest of my life," she says.


TMR Benefits

When an amputation is performed, the severed nerves form a neuroma, a disorganized nerve growth from the cut end, Loeffler says. "These can be very painful and hypersensitive for patients, which can limit tolerance for prosthetic wear," he says. "By taking those nerve ends and transferring them into a muscle, the nerve now has a purpose of innervating [stimulating] that muscle, so it will not form a painful neuroma."


The procedure also improves patient function, Gaston says. "The nerves that are cut during an amputation are still connected to the brain and thus have the capability of making muscles work; they simply lack the downstream muscles due to the amputation," he says. "By finding the remaining muscles in the arm, we can ‘switch innervate' remaining muscles to place them under control of the amputated nerve."


With respect to upper- versus lower-limb TMR, Gaston says, "lower-extremity patients still receive the benefit of pain control by treating or preventing neuroma formation, and we do perform TMR in lower-extremity amputees for this purpose. The added benefit of improved prosthetic control is not yet a benefit for lower-extremity prosthetics but may prove to have value for future prosthetic devices."


Before the shark attack, Johnson was unfamiliar with TMR, and she did not realize how advanced prosthetics had become. She says having the procedure was a game changer for her pain. "I have not taken medication for pain since last September," she says. "I do get tinges of pain every once in a while, but they are fleeting and only last a few seconds."


Recovery Continues

Johnson met her prosthetist, Michael Jenks, CPO, manager for Hanger Clinic in Charlotte when she met Gaston and Loeffler. A team from Hanger met with Gaston and Loeffler about five years ago with a shared mission to identify ways to improve outcomes for those with upper-limb amputations, enks says. To address the issue, an upper-limb team of occupational therapists, prosthetists, and surgeons was formed, which ultimately has led to improved outcomes and new device development for those with upper-limb amputations, he says.


Jenks has worked with Johnson through her rehabilitation and as she learned to use her myoelectric prosthesis, an Ottobock bebionic hand, a wrist rotator, and a custom silicone socket using the Coapt control system.

Seven weeks after her the surgery, Johnson was tested to determine if her arm would be able to send signals. "I was told that it usually takes at least three months after TMR surgery for the nerves to settle before I would be able to send signals that could result in an action with the prosthesis." However, she was able to signal the hand to open and close. "It was amazing," she says. "Everyone in the room was shocked that I was able to function so soon."

Jenks says the procedure will continue to benefit Johnson. "She has a very short residual limb and TMR allowed her remaining muscles to be innervated and gave us additional sites to pick up signals and utilize Coapt pattern recognition," he says. "She would only be able to use a single-site system with a very limited function if the TMR was not performed." Now, Jenks says, Johnson can operate a hand with multiple grip patterns and a wrist rotator. "It greatly enhances her function," he says.

Johnson received her second prosthesis in June that has a more aggressive fit than her first prosthesis, which she received last December. While the pain is under control, more scar tissue has built up by her elbow. Wearing her prosthesis, she has about a 70 percent bend, without it, 90 percent. She says she is considering another surgery to remove the scar tissue.


A Steady Faith

Johnson says her faith has helped her throughout the ordeal. A friend illustrated a biblical verse from Psalms, and Hanger worked with Fred's Legs in Florida to incorporate it on her prosthesis, Jenks says.

"No question that her faith has kept her strong," he says. "To go through such an ordeal yet still live with a purpose and energy to share her faith in a real and honest way. Anyone who speaks to her cannot have a doubt of her beliefs and convictions."

Johnson, who returned to work in January, is eager to get her busy life back to normal. "I love having my [prosthesis] as a tool to help me. I am able to do most tasks that require gross motor skills, however, the fine motor skills are where I still struggle," she says. "I have to give myself a lot of grace because I can't expect to do things faster or even the same way. It can be overwhelming at times, but my faith and trust in the Lord are what's gotten me through. I have been able to overcome by choosing peace instead of fear and joy instead of depression."


Betta Ferrendelli can be contacted at