Selective Dorsal Rhizotomy (SDR)

What is selective dorsal rhizotomy (SDR)?

Selective dorsal rhizotomy (SDR) is a surgical procedure performed on the lower spine to reduce spasticity (involuntary muscle contractions and stiffness) in the legs of children who have a spastic form of cerebral palsy.

Spasticity in children with cerebral palsy interferes with the development of motor skills. Over time, it can cause permanent problems as muscles weaken, and it can lead to contractures (fixed positioning of muscles).

SDR corrects muscle spasticity by cutting the nerve rootlets in the spinal cord that are sending abnormal signals to the muscles. Reducing the spasticity allows for improved motor control of the legs and, ultimately, an improvement in how a child stands and walks.

Benefits of SDR surgery

Selective dorsal rhizotomy, combined with physical therapy, can greatly reduce spasticity and improve mobility for children who have muscle spasticity that mostly affects their legs.

Who is a candidate for SDR?

Before recommending a patient for selective dorsal rhizotomy, our team performs a thorough screening that includes an evaluation in our Advanced Tone Management (ATM) Clinic. Our ATM team includes specialists from neurology, rehabilitation medicine, neurosurgery, orthopedic surgery, physical therapy and occupational therapy.  

Primary candidates for SDR surgery are children who fit the following criteria:

  • Primary tone problem is severe muscle spasticity in the legs that limits mobility
  • Cognitively able to follow directions and participate in therapy, as SDR surgery requires extensive rehabilitation

While the ideal age for SDR surgery is between 3-10 years old, there is not an age limit. Cases are considered on an individual basis.

Children with severe spasticity in their arms and legs may also be candidates for SDR surgery. For these children, the goal of the procedure is to increase independence, enabling them to sit for longer periods or to control movement in a wheelchair, as well as to ease the care required by caregivers.

Children will be evaluated for underlying muscle strength and control, as these are important for a successful SDR.

Children with significant dystonia are not ideal candidates for SDR.

How is selective dorsal rhizotomy performed?

SDR is performed while your child is under general anesthesia. A pediatric neurosurgeon makes a small incision over the middle of the spine to give the surgical team access to the nerve roots that run from the spinal cord to the muscles in the legs.

The motor (ventral) and sensory (dorsal) nerves are separated, and a pad is placed between them to remove the motor nerves from the field of operation. Using a surgical microscope, each of the sensory nerve roots is then separated into three to seven rootlets and stimulated electronically.

Other members of the surgical team — including physical therapists and electrophysiologists — measure how the leg muscles respond to the stimulation, identifying the specific rootlets that cause the greatest amount of spasticity. The most abnormal rootlets are cut, leaving the other rootlets intact.

What to expect during SDR surgery

Before selective dorsal rhizotomy surgery

In the weeks before the SDR procedure, your child will participate in physical therapy to strengthen and improve the range of motion in the trunk and leg muscles. You and your child will learn how to do these exercises at home, and you will be trained on the exercises to be done after the surgery. Arrangements will also be made for any adaptive equipment your child may need after the procedure.

In the days before the procedure, your child will be videotaped to make a record of presurgical mobility to compare with progress after the operation.

On the day of the surgery and immediately after

On the day of the surgery, your child will undergo general anesthesia. At Children’s Hospital of Philadelphia, you can trust our specially trained pediatric anesthesiologists to keep your child comfortable and safe before, during and after their procedure. Read more about our dedicated pediatric anesthesiology team.

The SDR surgery itself takes several hours, as a large number of nerve rootlets must be tested and selectively cut.

Most children can sit up and begin physical therapy on the first day after selective dorsal rhizotomy surgery.

The reduction in spasticity occurs immediately after surgery, and you may notice your child’s legs seem weaker because they have lost the spastic tone. Your child will be transferred to our inpatient rehabilitation unit a few days after surgery to undergo intensive therapy.


During inpatient rehabilitation, your child will receive daily physical therapy and occupational therapy. Therapy is designed to improve strength, balance, posture and gait, and to work toward regaining mobility and age-appropriate independence with self-care skills and activities of daily living.

Inpatient rehabilitation may also be a time to fit your child with any bracing or to teach them to use any new equipment that might be needed following surgery.

Children will generally remain on the inpatient rehabilitation unit for four to six weeks.

Before your child is released to go home, your medical team will review what you need to know about medication and what activities should be encouraged or avoided.

The therapists will also teach you strategies and a home exercise program that you will continue at home after inpatient rehab.

Your child will need to continue intensive physical therapy after discharge closer to home for the next six months to a year.

Going home after selective dorsal rhizotomy

Your child will continue to work with outpatient physical and occupational therapists in the community, which might be closer to where you live. You will have follow-up appointments with Rehabilitation Medicine as well as Neurosurgery to make sure that your child is healing well and to monitor their progress with therapy. Your child will also have yearly follow-up appointments in our ATM Clinic.

Why choose CHOP for SDR surgery

At Children’s Hospital of Philadelphia (CHOP), our Neuroscience Center works closely with the multidisciplinary Cerebral Palsy Program to ensure that candidates are screened appropriately for SDR and to provide the full range of supportive therapy before and after surgery to optimize outcomes.

Your child will have access to a broad team of experienced specialists with expertise in every element of the care of children with cerebral palsy, and who are committed to staying abreast of the latest technology available and innovative approaches to treatment.