ORANG Fighter Pilot is first in world to fly F-15 Eagle with a cervical prosthetic disc

  • Published
  • By Tech. Sgt. Steph Sawyer
  • 142nd Fighter Wing/Public Affairs

It’s a rainy December afternoon at Portland Air National Guard Base in Oregon. In the operations building, pilots are suiting up and getting ready to step for their afternoon sorties. Among them is Col. Todd Hofford, a 27-year Guardsman, and a seasoned F-15 Eagle fighter pilot with 2,500+ hours of flying under his belt. Although there have been many such days at PANG for Hofford, this one is significant. Three years of unyielding patience, effort, and perseverance have led up to this day: this is Hofford’s first official flight since having cervical disc replacement surgery. 


Hofford’s return to flying status is not only a personal milestone, but one for the U.S. Military and the world medical community also, because Hofford happens to be the first fighter pilot in the world to return to flying a high G fighter jet post-disc replacement surgery. 


For pilots of fighter jets, cervical injuries are commonplace. While degenerative disc disease to include herniations can occur in anyone, the extreme conditions fighter pilots are exposed to significantly increases the rate of occurrence. In fact, it’s stated in a 2018 dissertation titled Fighter Pilots’ Physical Performance and Spinal-injury Induced Flight Duty Limitations and published by the University of Jyvaskyla in Finland that the overall rate of spinal disorders reported in fighter pilots over their lifetimes ranges between 89% and 93%.    


To get a better idea, the average human head weighs approximately twelve pounds. The Joint Helmet Mounting Cubing System (JHMCS), designed to enhance a pilot’s situational awareness through technology adds another 6. For a pilot pulling 9Gs, that is a pressure of 9 times the force of gravity; your 18 pound head is now a 162 pound head which the bones and muscles of the neck must support and maneuver. Over time, this takes a toll on the spine. 


For Hofford, the herniation in his cervical spine was made evident by a knot in his back where the muscles were trying to compensate for the compromised disc. He then started to notice pain in his arms and tingling in his fingers. When these symptoms surfaced in 2014, Hofford worked with civilian and flight doctors to try to correct the problem through physical therapy.  


One day in August 2016, Hofford lost strength in his right arm completely. It became clear that surgical intervention was necessary in order to correct the herniation in his cervical spine. 


Historically, the medical procedure that has been performed to correct a disc herniation is known as a spinal fusion, or an anterior cervical discectomy and fusion (ACDF), wherein the herniated disc is removed and the bones on either side of the disc are fused together. 


With single level spinal fusion surgery, pilots historically have been able to recover and return to flying, but the known problem with this procedure is that by taking two vertebrae that are designed to move and fusing them together, some range of motion is lost. This results in increased intradiscal pressure and hypermobility of the adjacent segments. This means there is increased movement in the segments next to the fusion to compensate for lack of motion at the fused section. This inevitably causes an increase in wear, and as a result these adjacent segments often go bad, requiring additional corrective surgery.   


The mobility limitations and the increased rate of degradation of the sections adjacent to a spinal fusion are the issues that drove medical professionals to look to motion preserving artificial disc replacement surgery. 


Col. John Hall is the Air National Guard Assistant to the Command Surgeon, PACAF, and a board certified, fellowship trained orthopedic spine surgeon in private practice in a level one trauma center in Flagstaff, Arizona. Hall, having performed the third most prosthetic disc surgeries of any Spine Surgeon in the United States, is enthusiastic about what disc replacement could mean for military pilot’s abilities to return to flying after surgery and the possibility of increased quality of life well into retirement. 


Unlike spinal fusions, a disc replacement doesn’t hinder natural movement of the spine. This lessens the likelihood of needing more surgeries in the segments next to the prosthetic disc because the body won’t have to compensate for lack of mobility.


“We now have the ability to put a new disc in the neck or the back that actually moves for those patients,” says Hall. “It restores normal motion at that level and it reduces the rate of adjacent segment degeneration in the neck by 80%.” 


Disc replacement surgery is relatively new, however. It’s been practiced in the U.S. for approximately 12 years, and in Europe for about 20 years. Because it’s new, the Air Force only allows for pilots with cervical artificial discs to fly low G aircraft only. That is, pilots who have undergone this medical procedure are not authorized to fly fighter jets.


After learning about the benefits of disc replacement compared to spinal fusion, Hofford underwent surgery in September 2016. He made a full recovery and was cleared by a civilian Neurosurgeon to fly, but later found out that the military would not clear him to return to flying the F-15. 


Hofford knew that if he wanted to fly the Eagle again, he was going to have to make a case for himself and find people who had the necessary skill set and expertise to advocate for him. 


“I was determined to turn this around,” says Hofford. “I knew it was going to take time. I needed to be patient.” 


Hofford worked with Mr. Randy Ziobro, physical therapist, Duro Health CEO and developer of Fit4Flight, a program designed to prevent and treat injuries caused by the strain of flying military aircraft.


Fit4Flight was brought to Portland Air National Guard Base in November of 2015. Since the program’s implementation, pilots involved in Fit4Flight have been able to maintain their flight status by working actively to prevent and address issues before they interfere with their ability to do their jobs. Ziobro’s concept for the program encompasses the entirety of a pilot’s career, from hire all the way into retirement.  


“It’s about flying the Eagle and having mission readiness on 100% status for their spine,” says Ziobro. “But it’s about what their life after the military is going to be also.” 


After Hofford’s surgery, Ziobro worked with him to ensure and enable post-operative recovery as well as monitor and address symptoms, should they arise. The goal was to put Hofford on track for full recovery in order to achieve the waiver to fly again. 


In addition to his involvement in Fit4Flight, Hofford was also monitored and evaluated by Col. Hall who, through his unique experience, believed that getting these devices approved for flight in fighter aircraft stood to benefit both pilots and the military as a whole. 


“I think I’m the only person in the world who has more than 300 hours in fighters and has put in more than 400 artificial disc replacements,” says Hall. “I realized with my experience in tactical aviation and as a spine surgeon, there was a possibility that we would be able to return these people to their full flying duties.” 


For Hall, the opportunity to work with a pilot who has had the surgery and was willing to go through the arduous process of becoming cleared to fly presented the opportunity to impact the lives and careers of future fliers. 


“With advances in the field of medicine in general and spine surgery in particular, we found that aviators were getting the gold-standard surgery – artificial disc replacement” says Hall. “But by doing so, it was costing them their careers, and to me that was unacceptable. So my motivation was to try to evaluate the ability to safely marry this new technology with the demands of fighter aviation.”  


In 2016, Hall began a near three-year process with Hofford to get him cleared to fly the F-15 with the prosthetic in his neck. Hall researched extensively the world-wide scientific literature regarding the ability of these discs to withstand the rigors of tactical aviation, and used computer modeling to analyze crash scenario data, a proxy for the forces that the neck would experience during an ejection sequence.


“At the end of the day, I felt that although returning someone to tactical aviation with an artificial disc in their neck was not entirely risk free, the risk profile was very low,” says Hall. 


He worked with the Acceleration Branch at the 711th Human Performance Wing at Wright-Patterson Air Force Base, Ohio; the Medical Standards Directorate of the Air Force in Washington D.C. as well as the Aeromedical Consult Service (ACS), the Surgeon General of the Air National Guard, and the Chief of Aerospace Medicine of the Air National Guard.  


After several meetings, PowerPoints, conference calls, and reviews of the scientific data, Hofford arrived at Hall’s practice in Flagstaff for a full physical exam and x-rays. Next, Hall put him through an F-15 reevaluation in the centrifuge at Wright-Patterson AFB to see how well his neck would stand up to the forces one would experience in flight. Hofford passed these evaluations with outstanding results. 


Based on Hofford’s physical performance, Hall and his team elected to grant him an unrestricted waiver to return to flying the F-15. Hofford is now the first member of a study to evaluate his physical condition as he continues to fly. 


For Hofford, obtaining this waiver means being able to continue serving his country and the state of Oregon as an F-15 fighter pilot.


“It’s a privilege and an honor to be able to fly, fight and win in one of our weapon systems,” says Hofford. “I’m connected to the mission. I get to be part of protecting the homeland, and that’s extremely meaningful.”     


Hofford continues to work with Fit4Flight and has remained asymptomatic so far. 


Since Hofford’s requalification and return to flight, five more pilots have begun the process of being evaluated to return to fighter aviation post disc replacement surgery.