Location of spinal cord damage allowed surgeons to bypass damaged nerve in armFor the first time, surgeons have restored partial mobility to the hand of a quadriplegic patient.
The patient had suffered an injury to the lowest bone in his neck, and it was the specific location of the injury that allowed surgeons to avoid operating on the spine itself.
Instead, the team focused on the patient's still healthy upper arm nerves. Bypassing the hand's original (and now damaged) connection to the injured spine, the team effectively used the upper arm nerves to rewire a fresh connection to the intact motor control region of his brain.
A year of rigorous physical therapy later, the team of surgeons at Washington University School of Medicine in St. Louis reaped their reward: the restoration of the patient's ability to flex his thumb and index finger.
"This procedure is unusual for treating quadriplegia because we do not attempt to go back into the spinal cord where the injury is," surgeon Dr. Ida K. Fox, an assistant professor of plastic and reconstructive surgery, said in a news release from the university. "Instead, we go out to where we know things work -- in this case the elbow -- so that we can borrow nerves there and reroute them to give hand function."
Fox and her colleagues discuss the case in the May 15 online issue of the Journal of Neurosurgery.
The authors pointed out that their surgical approach would only be viable for patients like theirs: namely, those who sustain injury to the C7 (or C6) vertebra, located in the lower region of the neck. While such patients lose hand function, they retain function in their shoulder, elbow and wrist because the spinal region above the injury remains free of damage.
Those who suffer an injury to the C1 through C5 vertebra experience total arm function loss, and would not be eligible for this type of nerve bypass surgery, developed and performed by study senior author Dr. Susan E. Mackinnon, chief of the university's division of plastic and reconstructive surgery.
Mackinnon's initial goal had been more targeted: to restore thumb and index finger function to patients suffering from localized nerve damage. This is the first instance in which the approach was harnessed to overcome damage stemming from spinal cord injury.
The breakthrough, however, relies heavily on arduous post-surgical physical therapy, during which the patient's brain must be taught to recognize that the rewired nerves control the fingers rather than the elbow.
The good news: Any similarly injured patient with intact upper arm nerves would be eligible for this procedure, regardless of how much time has elapsed since the initial spinal cord damage. The current patient was operated on two years after his accident.
One expert explained why such surgery might work so long after a spinal cord injury.
"What this case demonstrated, and what is different from peripheral nerve-injured patients who undergo nerve grafts and nerve transfers, is that the motor neuron pool is intact and the muscle is preserved for a longer time than in peripheral nerve injury," said Dr. Lewis Lane, chief of hand surgery at North Shore University Hospital in Manhasset, N.Y. "If a peripheral nerve is cut, the lower motor neuron cell connection to the muscle is disrupted. However, in spinal cord injury the injury is, by definition, in the spinal cord, so the connection ... is not disrupted because peripheral nerves are intact.
"This connection is important for muscle preservation," Lane added, "and is the subtle but important distinction that allowed the procedure done on the patient in this case report to succeed more than 22 months after the injury."
The Washington University surgeons also noted that the procedure stood a good chance of success because of its simplicity.
"This is not a particularly expensive or overly complex surgery," Mackinnon said in the news release. "It's not a hand or a face transplant, for example. It's something we would like other surgeons around the country to do."
Dr. J. Marc Simard, a professor of neurosurgery, pathology and physiology at the University of Maryland School of Medicine in Baltimore, was excited about the success of the procedure.
"It's very important to caution that this applies only to those with spinal injuries far enough down on the spine that there are remnants of nerves that are still functional above the injury that can be tapped into," he noted.
"But, for these types of patients, this sounds perfectly reasonable and rational," Simard added, "based on the basic science work that's been going on for the last 25 years. And [it's] really a major step in the rehabilitation world."