Kris Boesen picked up a smartphone and texted someone four days following the procedure. He hadn’t been able to send one in months. It occurred as a result of a surgical team at USC’s Keck Medical Center opening the back of a young man’s neck in early April 2016, making a tiny incision in the membrane encircling his spinal cord, and gradually injecting 10 million stem cells—thick, according to the surgeon, like toothpaste—through a syringe into the injury site. After that, they shut him up and bided their time.
On March 6, 2016, just before he turned 21, Boesen had the night that would change his life. In Maricopa, California, he was driving his white Nissan 350Z on a winding, wet road when it fishtailed out of control and hit a curb, a tree, and a telephone pole. His neck was broken by the impact. He was able to move his left arm up and down, his hands were clenched, and his legs were completely unresponsive when the medical team examined him later. He was unable to hold a fork. He was unable to use a wheelchair. He was unable to perform nearly all of the tasks necessary for an independent adult life. “I was basically just existing,” he subsequently stated. “I wasn’t really living my life.”
| Category | Details |
|---|---|
| Patient | Kristopher “Kris” Boesen, 21 years old at time of injury — from Bakersfield, California |
| Injury | Traumatic cervical spinal cord injury sustained March 6, 2016, when his car fishtailed on a wet road in Maricopa, California, striking a tree and telephone pole |
| Condition Before Treatment | Could only move his left arm up and down; hands locked in a clenched position; unable to feed himself, use a wheelchair independently, or use his legs |
| Lead Surgeon | Charles Liu, MD, PhD — Director, USC Neurorestoration Center, Keck Medicine of USC |
| Clinical Trial Name | SCiStar — Phase 1/2a trial evaluating safety and efficacy of escalating doses of AST-OPC1 cells |
| Treatment | 10 million AST-OPC1 (oligodendrocyte progenitor cells) injected directly into cervical spinal cord — cells derived from embryonic stem cells and grown by Asterias Biotherapeutics |
| Surgery Date | Early April 2016 — approximately one month after injury; timing critical due to narrow biological window between inflammation clearing and scar tissue forming |
| How Cells Work | Oligodendrocytes produce myelin — the insulating material around nerve fibers; injected cells repair damaged insulation, invite blood vessels back to injury site, and release nourishing factors for surviving nerves |
| Results at 90 Days | Gained significant motor function improvement across two spinal cord levels; able to feed himself, use a cellphone, write his name, operate a motorized wheelchair, and hug family members |
| Institution | Keck Medical Center of USC — one of six U.S. sites authorized to enroll participants; sponsored by California Institute for Regenerative Medicine |
| Trial Eligibility | Ages 18–69; injury must be stable enough to receive injection between 14th and 30th days post-injury |
| Next Steps (at time of reporting) | Researchers planned to double the dose to 20 million cells and expand to patients with less-severe injuries; broader USC stem cell research targeting HIV/AIDS, Alzheimer’s, macular degeneration, and osteoarthritis |
Seeing that Boesen might be eligible for an experimental clinical trial being conducted at Keck Medicine of USC, his neurosurgeon at the nearby hospital called Charles Liu, director of the USC Neurorestoration Center. Boesen had to wean himself off a ventilator in five days, a process that typically takes three weeks, in order to give voice consent to participate, among other requirements set in motion by that phone call. He carried it out. Then he signed his consent form with an X while holding a pen in his still-clenched hand.
The cells that Liu injected are known as oligodendrocyte progenitor cells, a term that sounds extremely technical but actually refers to something that the body actually needs. Myelin, the insulating substance that envelops nerve fibers like rubber does an electrical wire, is produced by oligodendrocytes. Nerve signals are no longer able to effectively travel past the site of injury when the spinal cord is damaged or destroyed. The idea behind the AST-OPC1 treatment, which was created by Asterias Biotherapeutics in Fremont, California, was that by injecting these progenitor cells, the damaged insulation could be repaired, blood vessels could be drawn back into the area of injury, and factors that nourish dying but not yet dead nerves could be released. Liu held his breath while giving the injection in the operating room. In order to keep Boesen’s lungs from moving his spinal cord during the procedure, the anesthesiologist had stopped his breathing. Everyone was waiting.
Boesen started to improve two weeks after surgery. After 90 days, the improvement in motor function across two spinal cord levels was so noticeable that Liu used clinical terminology to describe it. The difference between being able to use a computer or brush your own teeth and not being able to do either of those things, according to Liu, makes two levels seem insignificant until you see what it actually means. By then, Boesen was able to use his cellphone, feed himself, write his name, operate a motorized wheelchair, and give his parents hugs. If you take a moment to consider it, the last one is not a minor issue.
It’s important to clarify what Liu and his associates were and weren’t claiming. They were not claiming that Boesen would be able to walk again because, despite Boesen’s own desire, this goal is still beyond the capabilities of current stem cell research to consistently treat severe spinal cord injuries. What they were witnessing was a recovery that deviated significantly from the typical course, showing greater improvement than the average patient with this kind of injury typically does.
This suggests, but does not prove, that the stem cells made a significant contribution. It can be challenging to distinguish the effects of treatment from natural recovery and intensive rehabilitation. Liu was clear about the caution that scientists who have dedicated their careers to studying the spinal cord are taught to be wary of premature enthusiasm. The main purpose of the trial was to evaluate safety. The initial outcomes were encouraging enough to proceed with doubling the dosage.
As you watch this story unfold—the wet road, the phone call to Liu, the five-day ventilator wean, the X on the consent form—it seems almost unbelievable how many things had to go perfectly for Boesen to be in that operating room at all. The surgical window was limited because the cells had to be injected two to four weeks after the injury, after the initial swelling had subsided but before scar tissue could develop. According to his father, the coordination needed between hospital teams, rehabilitation specialists, and the clinical trial infrastructure was a sort of coordinated miracle in and of itself.
For the majority of medical history, injuries to the spinal cord were regarded as a closed chapter. The story that USC’s team started writing in 2016 is different; it is unfinished, still evolving, and resistant to simple conclusions, but it clearly points in a direction that medicine once claimed didn’t exist.
