• Corrective surgery for scoliosis in children with spinal muscular atrophy (SMA) type 1 can lead to more serious complications during and after surgery, according to a new study.
• Four children with SMA type 1 who underwent successful surgery were able to resume receiving nusinersen injections into their spines, but they had serious complications that raised concerns about the procedure.
• The doctors concluded that the surgery should only be performed after careful consideration and weighing of the risks and benefits.

Nusinersen, sold as Spinraza, is a common treatment for people with SMA — and to work, it needs to be injected directly into a person’s spine. However, it can be difficult to administer in children with kyphoscoliosis, which causes the spine to bend outward and to the side. A recent case series has found that children with SMA type 1 who undergo corrective surgery for severe scoliosis are able to resume Spinraza treatment — but the surgery can also cause significant complications.

Kyphoscoliosis Can Interfere With SMA Treatment

SMA is a neurodegenerative disorder that affects special nerve cells known as motor neurons. These cells are responsible for sending movement signals from the brain to the muscles — in SMA, these are disrupted, making movement difficult.

There are five types of SMA that are divided by their severity. SMA type 1 — also known as Werdnig-Hoffmann disease — is the most common and accounts for 60 percent of cases.

Nusinersen is a specialized medication made of small fragments of genetic material that help fix errors in the survival motor neuron (SMN) genes. Due to its makeup, nusinersen must be injected directly into the spine as an intrathecal injection.

Kyphoscoliosis can make it difficult to administer nusinersen. For this reason, doctors at Children’s Health Ireland performed surgery to correct kyphoscoliosis in four children with SMA type 1.

Surgery Leads to Serious Complications

Between July 2020 and June 2021, four children with SMA type 1 — ages 3, 4, 5, and 7 — underwent surgery to correct their kyphoscoliosis. Children with SMA are at a higher risk for complications during surgery compared to those without the disease — including urinary tract infections, infections around the surgical site, and respiratory failure.

Overall, the surgical procedures were successful and all of the children were able to resume their nusinersen injections. This is important because the drug needs to be given every four months for the rest of the childrens’ lives. A recent study, however, found that more than half of people who start Spinraza for SMA stop within two years.

The children in the study also developed more serious complications after the procedure, such as pain and instability, infections, cerebrospinal fluid leaks, and wound opening. Many of these complications required additional surgeries and lengthy hospital stays.

The findings highlight the need for doctors to thoroughly discuss with parents and guardians the benefits and risks of this type of surgery on their children.

“As more children with SMA1 receive nusinersen treatment, more will present for scoliosis correction surgery,” the researchers wrote. “With the risk of a prolonged recovery, surgical, and anesthetic complications, a detailed discussion regarding risks and benefits must be had with the guardian before undertaking such procedures.”