Calvin Steede, who lives in Bermuda, will never forget the day in 2011 when he saw the movie “Winnie the Pooh” with his mother and sister. The film ended, and suddenly the boy who likes to draw and play soccer couldn’t put on his backpack. His arms had stopped working. He couldn’t stand, and soon he couldn’t talk.
Calvin, now 11, had suffered a minor stroke, a complication of sickle cell disease and the first step of a journey that would take him to Dana-Farber/Boston Children’s Cancer and Blood Disorders Center for minimally invasive surgery to protect his brain from future strokes.
Sickle cell disease
Sickle cell disease is an inherited genetic disorder in which red blood cells become sickle-shaped. Unlike healthy, round red blood cells, the sickled cells get stuck traveling through blood vessels, which causes blockages that can lead to pain and organ damage—and stroke, when blood flow to the brain is blocked.
Calvin also developed moyamoya, another potential complication of sickle cell disease in which the body forms fragile, wispy vessels in the brain to bypass a larger, blocked artery. The term moyamoya is Japanese for “puff of smoke,” which is what images of the new, tiny blood vessels resemble. Left untreated, patients with moyamoya, whether from sickle cell disease or other conditions, are at high risk of recurrent stroke or death. The moyamoya disease affects the entire length of the primary blood vessel, often very deep in the brain, so operating directly on it is not possible.
Enter Dr. R. Michael Scott and his protégé Dr. Edward Smith, neurosurgeons at Boston Children’s Hospital. In the late 1980s, Scott developed a pioneering surgical technique for moyamoya that dramatically reduces the risk of brain damage.
Taking a blood vessel from the blood-rich scalp, the surgeon makes a small opening in the skull and diverts the scalp vessel to the surface of the patient’s brain. Where Japanese neurosurgeons had simply placed the rerouted vein on the brain, Scott’s innovation was to attach it. From there, nature does its work, and the sturdier, relocated blood vessel gradually takes over from the moyamoya. Smith compares it to routing a new pipe through a window rather than destroying interior walls to unclog the blocked pipe inside.
Calvin’s surgery was originally scheduled for January 2012, but an angiogram showed the single area of narrowing thought to be early-stage moyamoya had improved.
By 2014, it had progressed, on both sides this time, and in May 2014, Calvin had moyamoya surgery. “Once Dr. Smith explained how dire the situation was, leaving it alone was not an option,” says Gina Steede, Calvin’s mother.
“If you take your average kid with sickle cell disease, there’s about a 10 percent chance he’ll have a first stroke by the time he leaves pediatric care,” says Dr. Matthew Heeney, clinical director of the Blood Disorders Center at Dana-Farber/Boston Children’s. “Once a child with sickle cell disease has a first stroke, regular blood transfusions dramatically reduce the risk of a second stroke, but the child who also has untreated moyamoya is roughly twice as likely to suffer a second stroke, even with regular transfusions.”
The 5 percent rate of post-surgical complications for patients with sickle cell disease, says Smith, is slightly higher than the 4 percent rate for other moyamoya patients. Smith and Scott worked with Heeney and his hematology colleagues to develop protocols specific to moyamoya in patients with sickle cell disease that are now published guidelines. “We really are a multidisciplinary team managing moyamoya for a very fragile population,” Smith says.
Using an angiogram or special MRI (magnetic resonance image), radiologists confirm the existence of the moyamoya and also determine when there may be a need to operate on asymptomatic patients. Sickle cell patients are hydrated before surgery to improve blood flow. They also receive a transfusion of matched healthy blood within a week before the operation. After surgery, hematologists help manage fluids and take care of patients’ lungs so they don’t get acute chest syndrome, a complication of sickle cell disease characterized by coughing, fever and pain.
Calvin gets monthly blood transfusions in Bermuda to prevent future strokes and decrease the likelihood that he’ll suffer a debilitating pain crisis. He takes aspirin daily to improve his blood flow, stays well hydrated, and returns to Dana-Farber/Boston Children’s for yearly checkups and tests.
Until recently, Calvin’s hair covered the surgical scars on each side of his head. This spring, after his barber suggested he display the scars with pride, Calvin had his hair shorn short. One scar resembles a lightning bolt.
“People don’t say I’m weird or anything, because they like me,” Calvin says. “My scars look pretty nice, and people don’t judge me by them. It makes me feel good to have my scars and be able to talk about it.”