Selective Dorsal Rhizotomy: Surgery for Leg Spasticity in Children

What Is Selective Dorsal Rhizotomy (SDR)?

Selective Dorsal Rhizotomy (SDR) is a neurosurgical procedure that permanently reduces leg spasticity in children with cerebral palsy by selectively cutting sensory nerve rootlets in the lumbar spine that are sending abnormal signals causing muscle stiffness. The surgery typically reduces spasticity by 70-90% in appropriately selected patients.

Spasticity is a particular form of increased muscle tone that occurs when the brain sends abnormal signals to the muscles. In children with cerebral palsy (CP), this often manifests as stiff, tight leg muscles that make walking difficult, cause pain, and can lead to orthopedic deformities over time. While spasticity itself is caused by brain injury, the abnormal signals travel through specific nerve pathways that can be interrupted surgically.

SDR works by accessing the lumbar spine (lower back) and identifying the sensory (dorsal) nerve roots that carry signals from the legs to the spinal cord. Using sophisticated electromyographic (EMG) monitoring, surgeons can identify which specific nerve rootlets are carrying the abnormal signals that cause spasticity. These abnormal rootlets are then selectively cut, while preserving the normal rootlets that are essential for sensation and motor function.

The procedure was first developed in the 1970s and has been refined over decades to become a well-established treatment at specialized pediatric neurosurgery centers worldwide. Modern techniques using single-level laminectomy (removing bone from only one vertebra) have significantly reduced operative time and improved recovery compared to earlier approaches. The surgery is considered when other treatments such as botulinum toxin injections, oral medications, or physical therapy have not adequately controlled spasticity.

Who Developed SDR and Where Is It Performed?

The modern technique of SDR was pioneered by Dr. Warwick Peacock in South Africa in the 1970s and later refined by Dr. T.S. Park at St. Louis Children's Hospital in the United States. Today, SDR is performed at specialized pediatric neurosurgery centers in North America, Europe, Asia, and Australia. The surgery requires a multidisciplinary team including pediatric neurosurgeons, neurophysiologists, anesthesiologists, and rehabilitation specialists.

Not all hospitals offer SDR, and outcomes are significantly better at high-volume centers with experienced surgeons. When considering SDR for your child, it is important to seek evaluation at a center that performs the procedure regularly and has comprehensive rehabilitation programs in place.

Who Is a Good Candidate for SDR Surgery?

Ideal SDR candidates are children aged 3-6 years with spastic diplegia (CP primarily affecting the legs), good underlying strength, ability to participate in rehabilitation, and spasticity that is the main barrier to movement. Children must undergo comprehensive multidisciplinary assessment to determine if SDR is appropriate.

Not all children with cerebral palsy are suitable candidates for SDR. The surgery works best for a specific subset of children, and careful patient selection is critical for optimal outcomes. The multidisciplinary team will assess several factors when determining if your child is a good candidate.

The ideal candidate for SDR typically has spastic diplegia, which means spasticity primarily affects the legs rather than the arms. Children with spastic quadriplegia (affecting all four limbs) may also be considered, but outcomes are generally better in diplegia. The child should have good underlying muscle strength beneath the spasticity – when the stiffness is temporarily reduced (such as during sleep or under anesthesia), the limbs should move relatively well.

Age is an important consideration. Most centers prefer to perform SDR on children between ages 3 and 6 years, though some will consider children up to age 10 or occasionally older. Operating at a younger age allows children to benefit from reduced spasticity during critical developmental years when they are learning to walk and developing motor skills. However, children must be old enough to participate meaningfully in rehabilitation.

Essential Criteria for SDR Candidacy

• Spastic cerebral palsy: SDR only works for spastic-type CP, not athetoid, ataxic, or mixed forms
• Primarily lower limb involvement: Best results in children with diplegia or triplegia
• Adequate underlying strength: Child should have some voluntary leg movement
• Cognitive ability: Child must be able to participate in intensive physiotherapy
• Spasticity as the main barrier: Weakness, dystonia, or fixed contractures may limit benefits
• Family commitment: Parents must be prepared for 1-2 years of intensive rehabilitation
• No progressive neurological conditions: SDR is not appropriate for progressive disorders

Who May Not Be a Good Candidate?

SDR may not be recommended for children with significant fixed contractures (permanent muscle shortening), severe dystonia (involuntary twisting movements), or those who rely on their spasticity for function (some children use stiffness to help them stand or walk). Children with significant cognitive impairment may have difficulty participating in the intensive rehabilitation program, which is essential for good outcomes.

The assessment process typically includes clinical examination by multiple specialists, gait analysis (video recording of walking patterns), muscle strength testing, and often MRI imaging of the brain and spine. This comprehensive evaluation helps the team predict how much benefit your child is likely to gain from surgery.

What Are the Benefits of SDR Surgery?

SDR can permanently reduce leg spasticity by 70-90%, leading to improved mobility and walking ability, reduced pain, better balance and coordination, easier daily activities such as dressing and bathing, and decreased need for other spasticity treatments like botulinum toxin injections.

The primary benefit of SDR is a permanent reduction in leg spasticity. Unlike botulinum toxin injections which wear off after 3-6 months, or oral medications which have systemic side effects, SDR provides lasting relief. Studies following children for 10-20 years after surgery consistently show that the reduction in spasticity is maintained long-term.

Reduced spasticity translates into multiple functional improvements for children. Many children experience significant improvement in their walking ability, with studies showing that approximately 50-70% of children who were walking before surgery improve their gait pattern, increase their walking speed, or reduce their dependence on walking aids. Some children who were minimally ambulatory or using walkers can progress to independent walking with crutches or even without aids.

Beyond mobility, SDR frequently results in reduced pain. Many children with spasticity experience chronic muscle pain from constant tension, muscle cramps, and spasms. Parents often report that their children are more comfortable after surgery, sleep better, and are generally happier. The reduction in pain also makes physiotherapy more tolerable and effective.

Functional Improvements After SDR

Daily activities often become significantly easier after SDR. Children may find it easier to dress and undress, particularly putting on pants, shoes, and socks. Bathing and personal hygiene can become more manageable. Parents often report easier diaper changes or toileting for younger children. These improvements in daily function can reduce caregiver burden and increase the child's independence.

SDR can also prevent or delay orthopedic complications. Without treatment, persistent spasticity can lead to hip displacement, scoliosis (spinal curvature), and fixed contractures that may require orthopedic surgery. By reducing spasticity early, SDR may decrease the likelihood of needing future orthopedic procedures.

How Is SDR Surgery Performed?

SDR surgery involves general anesthesia, a small incision in the lower back, removal of a small piece of bone to access the spinal canal, identification of nerve roots using EMG monitoring, and selective cutting of abnormal nerve rootlets. The procedure takes 6-8 hours, and the child lies face-down throughout surgery.

Understanding what happens during SDR surgery can help parents feel more prepared. The surgery is performed under general anesthesia, meaning your child will be completely asleep and feel no pain during the procedure. Parents are typically allowed to stay with their child until they fall asleep, then wait in a designated family area during the surgery.

Once anesthesia is established, the child is carefully positioned face-down on the operating table with special padding to protect pressure points. The surgical team includes the neurosurgeon, anesthesiologist, neurophysiologist (who operates the EMG monitoring equipment), and surgical nurses. A urinary catheter is placed to monitor kidney function and fluid balance during the long procedure.

The surgeon makes an incision in the lower back, typically 4-8 centimeters long, centered over the lumbar spine. Modern SDR techniques use a single-level laminectomy, which means removing a small window of bone from only one vertebra (usually L1) to access the spinal canal. This is less invasive than older techniques that required removing bone from multiple vertebrae.

The Nerve Root Selection Process

Once the spinal canal is opened, the surgeon identifies the cauda equina – the bundle of nerve roots that extends from the spinal cord to supply the legs. The nerve roots are carefully separated and classified into ventral (motor) and dorsal (sensory) roots. Only the dorsal (sensory) roots are tested and potentially cut, as these carry the abnormal signals that cause spasticity.

The neurophysiologist uses electromyographic (EMG) monitoring to test each dorsal nerve rootlet. Small electrical stimulation is applied to each rootlet, and the EMG electrodes placed on the leg muscles record the response. Normal rootlets produce a normal, controlled muscle response. Abnormal rootlets that are contributing to spasticity produce an exaggerated, spreading response.

Based on the EMG responses, the surgeon selectively cuts between 50-70% of the abnormal rootlets while preserving the normal ones. This selective approach is crucial – cutting too few rootlets may not adequately reduce spasticity, while cutting too many could cause weakness or sensory loss. The process is repeated for multiple nerve roots supplying different muscle groups in the legs.

After all the abnormal rootlets have been cut, the surgeon closes the wound in layers and applies a sterile dressing. The entire procedure typically takes 6-8 hours, after which the child is transferred to the recovery room where parents can be reunited with them.

How Should We Prepare for SDR Surgery?

Preparation for SDR includes pre-operative appointments with the surgical team, blood tests and imaging, physiotherapy assessment to establish baseline function, discussing the procedure with your child using age-appropriate language, and practical preparations such as arranging time off work and organizing post-discharge care.

Preparing for SDR surgery involves both medical preparations and practical family planning. The surgical team will provide specific instructions, but there are several things you can do to help ensure everything goes smoothly.

In the weeks before surgery, your child will have pre-operative appointments with the neurosurgery team, anesthesiologist, and physiotherapist. These visits allow the team to review the surgical plan, explain what to expect, and answer your questions. Blood tests and possibly additional imaging (such as spine MRI) may be performed to ensure your child is healthy for surgery.

The physiotherapy team will perform a baseline assessment before surgery, documenting your child's current abilities, muscle tone, and movement patterns. This provides an important comparison point for measuring improvement after surgery. Video recording of walking and other activities may be included.

Preparing Your Child Emotionally

How you prepare your child emotionally depends on their age and understanding. For younger children, simple explanations are best: "The doctors are going to help your legs work better, and you'll need to stay in the hospital for a little while." Many hospitals have child life specialists who can help prepare children using dolls, play, and age-appropriate books about surgery.

Older children can understand more detail and may benefit from seeing photos of the hospital room and meeting the rehabilitation team beforehand. It's important to be honest that there will be some discomfort after surgery, but that the doctors and nurses will give medicine to help with pain. Focusing on the positive goals – being able to move more easily, having less pain, doing activities they want to do – can help children feel motivated.

On the day before surgery, your child will typically be admitted to the hospital. They will need to fast (no food or drink) from midnight before surgery. The team will confirm the surgical plan and answer any final questions. Try to keep the atmosphere calm and positive – children pick up on parental anxiety.

What Is Recovery Like After SDR?

After SDR surgery, children typically stay in hospital for 7-10 days. Recovery involves pain management, gradual mobilization, and starting physiotherapy within days of surgery. Children often experience temporary weakness and may notice tingling sensations. Most children return to school within 6-8 weeks, with intensive rehabilitation continuing for 1-2 years.

When your child wakes up from anesthesia, you will be able to be with them in the recovery room. It is normal for children to be groggy, confused, or upset as they wake up. Pain management is a priority in the first few days – your child will have a patient-controlled analgesia (PCA) pump or regular pain medication to keep them comfortable. Don't hesitate to ask the nursing staff for additional pain relief if your child seems uncomfortable.

For the first 1-3 days, your child will need to lie flat or with only slight head elevation to allow the surgical site to heal and prevent spinal fluid leakage. Turning from side to side is encouraged to prevent pressure sores, but sitting up is restricted initially. Nausea from the anesthesia is common in the first 24-48 hours.

By day 3-4, most children can begin sitting up gradually and starting gentle physiotherapy exercises in bed. The physiotherapist will teach exercises to maintain range of motion and begin strengthening. Standing and walking typically begin by day 5-7, with support from the physiotherapy team.

What to Expect in the First Weeks

When your child first stands and tries to walk after SDR, they will notice that their legs feel very different. The spasticity that has been present their whole life is now significantly reduced or gone. Many children describe their legs as feeling "floppy," "heavy," or "like jelly". This is temporary – the muscles are the same, but without the extra tone from spasticity, they need to learn to work in a new way.

It is completely normal for children to walk worse initially after SDR than they did before surgery. This can be distressing for parents to see, but it is expected and temporary. With rehabilitation, walking will improve beyond pre-operative levels in the majority of children. Think of it like learning to ride a different bicycle – it takes time to adapt to how the new one handles.

Tingling sensations in the legs, sometimes described as "pins and needles" or a "fuzzy" feeling, are common after SDR. This usually resolves within the first month as the nerves settle. Some children also experience temporary urinary retention (difficulty emptying the bladder), which typically resolves within the first week.

Hospital Discharge and Going Home

Most children are ready to go home 7-10 days after surgery. Before discharge, the physiotherapy team will ensure your child can transfer in and out of bed safely, walk short distances with appropriate support, and that you are comfortable with the home exercise program. You will receive written instructions about wound care, activity restrictions, and when to call the medical team.

For the first 4-6 weeks at home, your child should avoid sitting for prolonged periods (limit to 30-60 minutes at a time), avoid bending, twisting, or lifting, and gradually increase activity as tolerated. Swimming pools, baths, and other water immersion should be avoided until the wound is fully healed (usually 2-3 weeks).

What Rehabilitation Is Needed After SDR?

Intensive physiotherapy rehabilitation is essential for successful SDR outcomes. Children typically need 5 days per week of physiotherapy for the first 3-6 months, then 2-3 times weekly for up to 2 years. Rehabilitation focuses on strengthening, balance, walking training, and functional skills. Maximum improvement is usually seen 1-2 years after surgery.

Rehabilitation after SDR is just as important as the surgery itself. Without intensive, skilled physiotherapy, children will not achieve the full benefit of spasticity reduction. The rehabilitation phase is demanding for families, requiring significant time commitment and ongoing motivation, but it is where the real gains are made.

In the first 3-6 months after surgery, most centers recommend physiotherapy 5 days per week. This may be a combination of hospital or clinic-based sessions and home exercises supervised by parents. The initial focus is on strengthening – without spasticity, the underlying muscle weakness becomes apparent and needs to be addressed. Core strengthening, leg strengthening, and postural exercises form the foundation.

As strength improves, rehabilitation progresses to balance and coordination training, gait (walking) training, and functional skills. Children learn to use their new, more flexible legs to move in efficient patterns. Standing exercises, stepping practice, and eventually walking with decreasing levels of support are introduced progressively.

The Role of Parents in Rehabilitation

Parents play a crucial role in their child's rehabilitation. The home exercise program is an essential supplement to formal physiotherapy sessions. These exercises need to be done daily, even when your child is tired or reluctant. Finding ways to make exercises fun and incorporating them into play can help with motivation.

After the intensive first phase, physiotherapy frequency gradually decreases. Most children continue therapy 2-3 times per week for the first year, then 1-2 times per week in the second year. Some children continue with less frequent sessions for several years as they work on higher-level skills and sports activities.

Maximum functional improvement is typically seen 1-2 years after surgery, but gains can continue for several years. Some families pursue intensive physiotherapy programs or camps during school vacations to accelerate progress. The rehabilitation journey requires patience – improvements are gradual, and there will be plateaus, but consistent effort over time produces the best outcomes.

What Are the Risks and Complications of SDR?

SDR is generally safe with low complication rates at experienced centers. Common temporary effects include back pain, leg tingling, and temporary weakness. Rare complications include wound infection (1-2%), spinal fluid leak (1-3%), and sensory changes. Serious permanent complications are rare when surgery is performed by experienced teams.

All surgeries carry some risk, and SDR is no exception. However, when performed at experienced centers with proper patient selection, SDR has a strong safety record. Understanding the potential risks can help you make an informed decision and know what to watch for during recovery.

Temporary effects that are common and expected include back pain at the surgical site (managed with pain medication), tingling or altered sensation in the legs (usually resolves within weeks), temporary leg weakness (expected and improves with rehabilitation), and urinary retention requiring temporary catheterization (usually resolves within a week).

Minor complications that occur in a small percentage of patients include wound infection (1-2%, treated with antibiotics), cerebrospinal fluid leak (1-3%, may require additional surgical repair), and temporary bladder dysfunction beyond the first week (uncommon, usually resolves). These complications, while inconvenient, are generally manageable and do not affect long-term outcomes.

Rare and Serious Complications

Serious complications are rare but can occur. Permanent sensory changes (numbness or hypersensitivity) in the legs can occur if too many sensory nerve rootlets are cut. This is minimized by careful EMG-guided selection during surgery. Permanent weakness is very rare with modern techniques that preserve motor nerve roots. Spinal instability requiring fusion surgery has been reported but is uncommon with single-level laminectomy.

It is important to note that SDR is an irreversible procedure. Once the nerve rootlets are cut, they cannot be reconnected. This is why careful patient selection is so important – the team needs to be confident that reducing spasticity will help rather than harm your child's function.

Some children may be disappointed with outcomes if expectations were unrealistic. SDR reduces spasticity but does not cure cerebral palsy. Children with significant underlying weakness, dystonia, or fixed contractures may see less improvement than hoped. Having detailed discussions with the medical team about realistic expectations before surgery is essential.

What Are the Alternatives to SDR?

Alternatives to SDR for managing leg spasticity include botulinum toxin (Botox) injections, oral medications (baclofen, diazepam, tizanidine), intrathecal baclofen pump, orthopedic surgery for contractures, and comprehensive physiotherapy programs. The best option depends on the individual child's situation.

SDR is not the only option for managing spasticity in children with cerebral palsy. Depending on your child's specific situation, other treatments may be more appropriate or may be tried before considering surgery.

Botulinum toxin (Botox) injections are commonly used to temporarily reduce spasticity in specific muscle groups. The toxin blocks nerve signals to muscles, reducing tone for 3-6 months. Advantages include minimal side effects and the ability to target specific muscles. Disadvantages include the need for repeated injections (every 3-6 months), expense, and the fact that effectiveness may decrease over time with repeated use.

Oral medications such as baclofen, diazepam (Valium), and tizanidine can reduce spasticity but affect the whole body, which may cause unwanted drowsiness or weakness. They are often used in combination with other treatments. Baclofen is most commonly used and is generally well tolerated, though it should not be stopped suddenly.

Intrathecal Baclofen Pump

An intrathecal baclofen (ITB) pump delivers baclofen directly into the spinal fluid through a surgically implanted pump. This allows lower doses that reduce spasticity without causing as much drowsiness as oral medication. The pump requires surgical implantation and refilling every 1-3 months. It can be adjusted as the child grows and is reversible (the pump can be removed if needed). ITB is often considered for children who are not ideal candidates for SDR or who have more generalized spasticity.

Orthopedic surgery may be needed to correct fixed contractures or bone deformities that have developed due to chronic spasticity. Procedures such as muscle lengthening, tendon transfers, and bone surgery address the structural consequences of spasticity. Orthopedic surgery is often combined with spasticity management rather than being an alternative to it.

Comprehensive physiotherapy and rehabilitation remain the foundation of CP management regardless of other treatments. Some families choose to pursue intensive physiotherapy programs without surgical intervention, particularly if the child's spasticity is mild or if there are contraindications to surgery.

What Are the Long-Term Outcomes of SDR?

Long-term studies following children for 10-20+ years after SDR show that spasticity reduction is maintained permanently, gross motor improvements are preserved, and many adults report satisfaction with their surgery. However, the underlying cerebral palsy remains, and some children may still need additional treatments over time.

Parents naturally want to know what their child's life will look like years after SDR surgery. Long-term outcome studies provide encouraging evidence that the benefits of SDR are lasting.

Multiple studies following children for 10-20 years or more after SDR have found that the reduction in spasticity achieved by surgery is permanent. The nerve rootlets that were cut do not regenerate, so the spasticity does not return. This is in contrast to botulinum toxin injections, which need to be repeated regularly.

Functional improvements achieved through surgery and rehabilitation are generally maintained long-term. Studies show that most children who improved their walking ability after SDR continue to walk better as adults than they would have without surgery. However, some decline in function can occur during adolescence due to growth spurts, weight gain, and decreased physiotherapy intensity – this is not specific to SDR but is a general challenge in CP management.

Quality of Life and Patient Satisfaction

Adult survivors of SDR generally report high satisfaction with their surgery. Surveys of adults who had SDR as children find that the majority would recommend the surgery to others and feel it improved their quality of life. Benefits mentioned include reduced pain, easier mobility, greater independence, and fewer orthopedic problems than peers with similar CP who did not have SDR.

It is important to have realistic long-term expectations. SDR reduces spasticity but does not cure cerebral palsy. The underlying brain injury remains, and children will continue to face challenges related to their CP. Some children may still require orthopedic surgery for contractures or hip problems despite having had SDR, though the need for orthopedic intervention appears to be reduced. Ongoing physiotherapy and maintenance exercise are beneficial throughout life.

As children who had SDR reach adulthood, they transition to adult healthcare services. Finding providers experienced in CP care for adults can be challenging in some areas. Maintaining an active lifestyle and healthy weight becomes increasingly important for preserving mobility gains.