When it comes to cerebral palsy (CP) — injury to the developing brain that can affect muscle control, coordination, tone, reflex, posture and balance — parents have a lot of questions about surgical approaches. In fact, selective dorsal rhizotomy (SDR) is a hot topic among physicians and parents alike. This minimally invasive spinal operation can permanently reduce leg spasticity and encourage independent walking in properly selected children with CP. It may be a complementary option along with other therapies, such as physical therapy, systemic medications, Botox injections and orthopedic procedures.
Yet, despite its popularity, SDR isn’t right for every child. Here, Dr. Benjamin Shore and Dr. Scellig Stone, two of the co-directors of the Cerebral Palsy and Spasticity Center at Boston Children’s Hospital, discuss the potential benefits and risks of SDR and other procedures.
What happens during SDR?
In this procedure, a neurosurgeon makes a small cut in the upper lumbar region of the child’s spine and removes a small section of bone to expose the nerve roots as they leave the spinal cord. They then separate the nerve roots into groups, finding those that bring sensation back from the legs and leaving the motor nerves aside. Probes are used to deliver electrical impulses to the sensory nerves in order to identify which part of the leg they come from and whether or not they show signs of “hyperactivity.” Each nerve fiber is divided into smaller nerve rootlets, and a little over half of these rootlets (the ones that are most abnormally hyperactive) are cut. The surgical team then carefully closes the wound.
What are the potential benefits of SDR?
SDR is a permanent treatment. “It’s a one-time operation that’s a permanent reduction in abnormal tone, which has the potential to have lasting benefits for some kids,” explains Stone.
Who is most likely to benefit from SDR?
Although CP can affect tone in many different areas of the body, SDR is best for children who have increased tone in their legs. “The ideal candidate is someone who can walk, who is younger than age 10 or so, for whom tightness in the legs is making it difficult to walk, and for whom medical treatments haven’t worked,” says Stone.
The dilemma, says Shore, is that many kids with CP have both increased tone and weakness. Gait analysis and careful consideration of the whole child from a team of different specialists are crucial when determining who will benefit most from SDR.
What are the risks of SDR?
SDR may be less beneficial if a child has a great deal of spasticity in their arms or requires support to sit up. “From gait analysis and other studies, we can see that some children are actually using excess tone to support weaker parts of their body,” says Stone. “If you take that tone away with SDR, you may leave them in a functionally weaker state that’s actually worse off.”
It’s also important to keep in mind that the recovery for SDR is long — kids who undergo this procedure will require long-term physical therapy and follow-up. “Just because you’ve had an SDR doesn’t mean that you’re done with seeing your physicians,” says Shore. “You may need additional interventions to maintain your function.
What is PERCS and how might it benefit kids with CP?
PERCS, also known as selective percutaneous myofascial lengthening (SPML), describes a group of orthopedic surgical procedures. In this approach, the surgeon identifies areas of tightness, makes tiny incisions where a tendon is tightest and release these tight structures using a small scalpel. Although it’s marketed as a less-invasive technique, “the reality is that the incision isn’t that much smaller than open surgery,” says Shore. “We like to dose our surgery according to each child, and we are unable to alter the dose through these small incisions, it is either all released or nothing.”