Nerve Surgery May Restore Function in Kids With Polio-Like Virus

Damian McNamara

November 20, 2018

Nerve transfer surgery for children paralyzed by acute flaccid myelitis (AFM) who have not responded to a year or more of medical management may help restore function in these patients, early experience suggests.

Dr Mitchel Seruya

Researchers led by Mitchel Seruya, MD, director of the Brachial Plexus and Peripheral Nerve Center at Children's Hospital Los Angeles in California, are finding improvements in clinical scores of muscle strength following the procedure.

Some of these patients are now once again playing baseball, performing plank exercises, and even winning Judo competitions, Seruya told Medscape Medical News.

Seruya has operated on 15 of the more than 20 children evaluated at his institution and has assessed outcomes for all of them.

"Luckily, we have about 4 years of data. I would say out of the 15 kids, 100% of them have increased function," said Seruya.

The researchers score muscle function on a scale of 0 to 7, with 0 representing the worst function and 7 the best. "The numbers have climbed in every kid" following surgery, he added.

Candidate Selection

Longitudinal data for 12 of the 15 patients suggest that mean scores improve at the shoulder by +1, at the elbow by +2, and at the wrist and hand by +2.5.

Importantly, the investigators devised a system to predict which patients are most likely to benefit from nerve transfer surgery. They compare muscle strength scores at baseline and 3 months after onset of paralysis to distinguish "spontaneous recoverers" from patients who are more likely to need surgery.

"The kids who will likely get better on their own generally double their scores by 3 months. So if their composite score improves from 15 to 30, for example, they are generally going to do well on their own," he said.

However, those whose scores remain unchanged or improve only slightly are more likely to require nerve transfer surgery.

"When we looked at this group at 9 months, 12 months, or 15 months, they were not getting better on their own. It's not to say they will not continue to recover after month 3, it's just that recovery will be incomplete [without surgery]," Seruya said.

"It's not just the scores that are going up, it's also the activities of daily living that remarkably change [with surgery]," he added.

Patients differ in the extent to which function returns, he said. Children who have been paralyzed for a shorter time and those whose donor nerves are strong tend to have the best outcomes.

"The Best Shot We Have"

Nerve transfer surgery is "not perfect," Seruya said. "It's not turning off the virus and completely reversing AFM." However, for children who have not improved through conventional medical therapy, "this surgery is the best shot we have."

It's always a win for the families, he added. "I haven't had a family yet regret going ahead with the surgery."

It all started in 2014 when Seruya was affiliated with Texas Children's Hospital in Houston. Neurologists managing an AFM patient with paralysis in both shoulders did not see a satisfactory response after 12 months of therapy with steroids and intravenous immunoglobulin. "They basically said to me: 'We've tried medical therapy — do you think anything else is possible?' "

Seruya performed nerve transfers in both shoulders. When the patient returned at 3 months, she brought her arms all the way up to the ceiling, he said. "So for someone with 12 months of medical therapy with no results, at 3 months, even without any formal occupational therapy, she already got function back in her shoulders.

"I thought that was amazing. The neurologist turned to me and asked, 'What did you do?' " Seruya said.

The procedure relies on finding strong donor nerves in which there is some redundancy. For example, for a child who unable to move his or her elbow, if three nerves are involved in bending the wrist, one is surgically "rewired" to a different muscle. The donor nerves remain connected to the spine at all times.

Seruya moved to Los Angeles in 2015 and continued evaluating children with AFM.

First Patient

"The first kid I operated on in LA was a 20-month-old with paralysis," he said. The child had some function in his hand and wrist but was unable to move his shoulder or his elbow in any direction.

After Seruya carefully counseled the parents about their child's limited options, the parents approved the nerve transfer surgery. The procedure lasted about 15 hours.

"I moved rib nerves to make his elbow extend and to make his shoulder elevate. Then I moved his wrist nerves so his elbow could bend and flex," said Seruya.

During the first 12 months of follow-up, the team saw little improvement.

"But it turned out we just needed to give it more time. What was amazing was 15 months [after surgery], we started to register electrical activity using surface EMG [electromyography]. By 18 months after surgery, this kid who had no elbow [function] was doing planks," he said.

"The surprising thing is we can even get in there late," Seruya added. The successful outcomes for the 20-month-old, for example, illustrate the effectiveness of going beyond the typical 12- to 18-month window.

So far, Seruya and the multidisciplinary team at Children's Hospital have operated only on upper extremities.

Amy Moore, MD, a surgeon at St. Louis Children's Hospital, in Missouri, was the first to perform nerve transfer procedures in the lower extremities of children with AFM.

In the shoulder and arms, there tend to be more nerves nearby to reallocate to the paralyzed muscle. Other nerves in the arm, as well as nerves located around the ribs and diaphragm, are potential candidates.

"Every kid that has come to me so far with leg involvement has been too far out" in terms of duration of paralysis, Seruya said. In addition, the legs tend to feature fewer viable donor nerves compared to the upper extremities. That being said, he recently evaluated a child with leg paralysis who may be a candidate, because the patient could wriggle his toes.

As with any medical condition, diagnosis of AFM generally relies on a combination of history, physical examination, and imaging studies, Seruya said. "I will say that acute flaccid myelitis or polio-like paralysis was not on the radar for most emergency departments until recently."

Recognizing AFM a "Major Hurdle"

Any child with a prodromal illness who presents with acute-onset paralysis in one or more limbs "would raise my clinical suspicion," Emmanuelle Tiongson, MD, a pediatric neurologist who is part of the multidisciplinary team in the Brachial Plexus and Peripheral Nerve Clinic at Children's Hospital Los Angeles, told Medscape Medical News.

The major hurdle in the beginning was just recognizing AFM, she said. "It's important for neurologists to just keep it mind, especially in the pediatric population."

Generally in such cases, enterovirus infections follow what appears to be a typical cough, cold, or an illness resembling a stomach flu. "So the symptoms themselves before AFM are very general," she added.

The most common alternative most neurologists consider is Guillain-Barre syndrome, "which is related but not exactly the same," she said. It is important to rule out infections, including meningitis and encephalopathy, through neuroimaging of the brain and spine and to assess the spinal fluid, she added.

The Centers for Disease Control and Prevention (CDC) is currently working on a consensus statement to help guide clinical diagnosis.

In the meantime, Tiongson said, "getting treatment early with intravenous immune globulin is the best we've been able to do so far. It can help boost the immune system to fight off this virus. I've been asked how contagious it is, and honestly, I don't know."

The CDC is also evaluating whether AFM is communicable and, if so, to what degree. Generally, the causative agent must be identified before such estimates can be made; an investigation to identify the agent is ongoing.

"We think it is enterovirus D68 or the related enterovirus A71; there have been more associations than not with these strains. But there is more to be done," she said.

The investigators plan to share their surgical assessment and outcomes data in the near future. They expect to present more information on their 3-month milestone for distinguishing "spontaneous recoverers" from surgical candidates at the annual meeting of the American Society for Peripheral Nerve in February 2019.

They also plan to discuss muscle function scoring outcomes in June 2019 at the International Federation of Societies for Hand Therapy congress. Thereafter, Seruya added, "we will submit these abstracts for full publication...as an original paper."

Dr Seruya and Dr Tiongson have disclosed no relevant financial relationships.

Follow Damian McNamara on Twitter: @MedReporter. For more Medscape Neurology news, join us on Facebook and Twitter.

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