Refining and Expanding Rhizotomy Helps More Children with Cerebral Palsy Improve Their Mobility

Libby Infinger, M.D.
Libby Infinger, M.D.

A multi-disciplinary team at MUSC Children’s Health including a pediatric neurosurgeon, a physical medicine and rehabilitation doctor, neurophysiologists, and physical therapists is improving outcomes for children with cerebral palsy (CP) by expanding access to Selective Dorsal Rhizotomy (SDR). The most common childhood motor disability, CP is caused by abnormal brain development or brain damage–often the result of oxygen deprivation at birth or premature birth. Children with CP have a range of motor dysfunctions that affect muscle control, coordination, muscle tone, reflexes, posture, and balance. While there are several types, spastic CP accounts for about 83% of cases and is characterized by muscular stiffness that is usually concentrated in the legs but can also affect the arms, torso, and face.1

Libby Infinger, M.D., pediatric neurosurgeon and Associate Professor of neurosurgery at the Medical University of South Carolina (MUSC) explains, “In spastic CP, an issue in the brain leads to problems regulating the standard reflex loops that allow smooth movements and normal muscle tone. There’s not a coordinated response to a stimulus. Essentially, there’s a hiccup in the feedback system that causes an extra strong reaction to normal stimulus. Muscle contraction can be unopposed, leading to stiff muscles that may ultimately progress to contractures and limit or disallow mobility.”

Treatments for CP include oral medication, an implanted medication pump, and SDR surgery to cut over-active nerves at the spine. “There are different schools of thought about using the pump versus rhizotomy surgery,” says Infinger. “The biggest benefit of SDR is that it provides lifelong benefits with just one procedure. The pump needs constant tune-ups. It has to be refilled often, depending on the pump size and medication dose. It also requires follow-up surgeries to replace the battery and fix mechanical issues. On the other hand, SDR is a one-time surgery that can potentially help the child increase walking ability and maintain functionality throughout life.”

Until recently, SDR was generally only offered to children whose legs were primarily affected (spastic diplegia) but who could walk with the aid of crutches or a walker. Conducting SDR–most commonly between age four and ten–in these children can improve mobility and help them maintain walking. However, those with more severe CP (spastic quadriplegia), affecting their arms and torso as well as their legs and who cannot walk, are not usually considered for SDR.

However, after seeing substantial palliative and quality-of-life benefits of SDR in this group, the team at MUSC Children’s Health is now expanding its use in more severely affected children. “A rhizotomy will not give a non-ambulatory child the ability to walk, but it can relieve their really terrible lower-limb spasticity and decrease the overall excitatory input. Some families have told me they see improvements in upper-limb function and cognitive skills as well, even though only the legs should be affected based on the surgery location,” says Infinger. “It’s the same procedure but with different goals. For these kids, it helps with caregiving by improving their mobility in terms of being able to open their legs to bathe and get dressed. It also lets them use less oral medication which is important because the meds can have very sedating side effects.”

The MUSC team is working both to expand the number of children who benefit from SDR and to refine the procedure using more minimally invasive techniques. The recent opening of two neuro-surgical suites equipped with 3-D exoscope technology was central to their efforts. “We can do this surgery very effectively through just a single-level laminectomy. Limiting exposure to one level of the spine means patients have much less pain and recover faster,” says Infinger. “The exoscope is easier to use and has literally taken hours off our procedure time. The imaging technology lets us use a smaller incision and quickly identify structures we need to work on. Everyone in the room can see exactly what I’m doing on a big monitor in real-time, so we work together more efficiently.”

Their multi-disciplinary approach includes a pain management protocol developed with the pediatric anesthesiology team to place an epidural catheter at the end of the surgery for direct delivery of pain medication. “Having this in place for the first few days after surgery can improve pain control and decrease the amount of strong oral or IV medication patients need for pain relief,” says Infinger.

Approximately 10,000 babies are born with CP each year in the US, with premature delivery and low-birth-weight being the biggest risk factors.2  While rates of this devastating neuro-muscular disorder have declined in some places, CP is more common in South Carolina where approximately 12% of births are premature, 10% of infants have low birth-weight, and measures of maternal and infant health are below national averages.3

The hope is that by making SDR more accessible, faster, and less painful, more children with CP or spasticity from other causes can benefit from this treatment–maintaining or gaining function and experiencing improved quality-of-life. To refer a patient or schedule an appointment, please call 843-876-0444.

References

1 Centers for Disease Control and Prevention, US Department of Health and Human Services. Data and Statistics for Cerebral Palsy. Available at: https://www.cdc.gov/ncbddd/cp/data.html. Accessed: March 1, 2021.

2 ibid

The Alliance for a Healthier South Carolina, Live Healthy South Carolina initiative. Maternal and Infant Health data. Available at: https://livehealthy.sc.gov/maternal-infant-health. Accessed: March 1, 2021.

Progressnotes Spring 2021