Selective Dorsal Rhizotomy for Spasticity: Who May Benefit and What to Know

Selective dorsal rhizotomy (SDR) is an operation intended to produce a lasting reduction in spasticity, mainly in the legs. It is most often considered for carefully selected children with spastic cerebral palsy, although some specialist centres assess other groups. SDR is not a cure for cerebral palsy, does not directly strengthen weak muscles and does not replace rehabilitation. Its value depends on choosing the right candidate, agreeing realistic goals and committing to a long period of therapy after surgery.

This guide explains what the operation changes, who may be assessed, why selection is demanding, what recovery can involve and which questions families should ask. Eligibility criteria and rehabilitation pathways differ between countries and specialist centres, so an individual multidisciplinary assessment is essential.

Key points

• SDR permanently divides selected sensory nerve rootlets in the lower spine to reduce the abnormal reflex activity that contributes to leg spasticity.
• The operation may reduce spasticity, but it cannot correct every movement difficulty. Weakness, reduced selective motor control, balance problems, dystonia and fixed contractures require separate assessment.
• Selection usually involves a specialist team including neurosurgery, rehabilitation medicine, physiotherapy and orthopaedics, with gait and functional assessment when appropriate.
• Intensive rehabilitation is not an optional extra. It is a central part of the treatment and may continue for many months or longer.
• Benefits and risks vary. Families should discuss the goals that matter in daily life rather than focusing only on lower muscle tone.

What is selective dorsal rhizotomy?

Spasticity develops when injury or altered development in the brain or spinal cord changes the control of stretch reflexes. Muscles may respond too strongly when they are moved quickly, contributing to stiffness, involuntary postures and difficulty with movement. In SDR, a neurosurgeon reaches the sensory nerve roots in the lower spinal canal. The roots are divided into smaller rootlets, tested with neurophysiological monitoring and selected abnormal rootlets are cut. Motor roots, which carry signals from the spinal cord to muscles, are preserved.

Reducing sensory input into the spinal reflex circuit can lower spasticity in the legs. The change is intended to be permanent because the divided rootlets do not simply grow back into their previous arrangement. This permanence is one reason assessment must be careful. Unlike an injection or a medication trial, the effect cannot be switched off if the functional balance is not as expected.

SDR addresses one component of the upper motor neuron syndrome. It does not repair the original brain injury and it does not directly treat impaired coordination, weakness, poor balance or involuntary movements caused by dystonia. Understanding the difference between these features is important; our guide to spasticity, rigidity and dystonia explains why a movement disorder assessment may change the treatment plan.

Who may be considered for SDR?

The best-established use of SDR is in selected children with bilateral spastic cerebral palsy whose legs are affected more than their arms. Many programmes focus on children who walk independently or with an aid and have the potential to improve the efficiency or quality of movement once spasticity is reduced. Some specialist services also consider non-ambulant children when carefully defined goals include comfort, positioning, ease of care or reducing painful spasms. These pathways are not identical and the evidence for different groups is not equally strong.

Age ranges and eligibility thresholds vary. A centre may consider the pattern of cerebral palsy, Gross Motor Function Classification System level, muscle strength, selective motor control, joint range, hip status, previous surgery, cognition, communication, general health and the family’s ability to participate in rehabilitation. The presence of spasticity alone is never enough to determine suitability.

Features that may support consideration include predominantly spastic lower-limb overactivity, useful underlying strength, clear functional or care goals, and access to a sustained rehabilitation programme. Factors that may reduce expected benefit or require a different strategy include marked dystonia, severe uncontrolled seizures, progressive neurological disease, major fixed deformity, very limited antigravity strength, significant spinal problems or health risks that make surgery unsafe. These are not universal pass-or-fail rules; they are issues for the specialist team to interpret.

Adults occasionally undergo SDR, usually after assessment in a centre with specific experience. Evidence and long-term pathways are less established than for selected children with cerebral palsy. An adult considering the operation should ask how many comparable patients the centre has treated, which outcomes it tracks and how rehabilitation will be organised.

For a broader view of movement problems and treatment choices, see spasticity in cerebral palsy and the overview of spasticity treatment.

Why the preoperative assessment is so detailed

The purpose of assessment is not simply to prove that spasticity is present. It asks a more useful question: if spasticity is permanently reduced, what movement, comfort or care outcome is realistically likely, and what difficulties will remain?

A multidisciplinary review commonly includes medical history, neurological examination, muscle tone, strength, selective motor control, balance, joint range, skeletal alignment, hip surveillance and observation of everyday function. Walking children may have video or instrumented gait analysis. The team may review imaging and previous responses to physiotherapy, orthoses, oral medicines or botulinum toxin. Tests and criteria vary by centre.

Measurements such as the Modified Ashworth Scale or Tardieu Scale can describe parts of the examination, but they cannot decide candidacy on their own. A lower tone score after treatment does not automatically mean easier walking or better participation. Read more about how spasticity is measured.

The team also looks for fixed contracture. A joint that cannot reach the required position because muscles and connective tissues have shortened will not become fully mobile simply because the stretch reflex is reduced. Orthopaedic procedures may still be needed before or after SDR. The distinction is explained in spasticity versus contracture.

Goals should be specific and observable

Useful goals might include walking a particular distance with less effort, reducing repeated falls, improving foot placement, making standing transfers easier, tolerating an orthosis, sleeping with fewer painful spasms or simplifying personal care. “Walk normally” or “remove all tightness” is too broad to guide a decision. A structured discussion about goals for spasticity treatment helps families compare the burden of surgery and rehabilitation with the outcomes that matter.

It is equally important to record what the operation is not expected to change. A child may continue to need an aid, orthoses, support at school or future orthopaedic care. Honest expectations protect the child and family from interpreting a technically successful reduction in spasticity as a failure because unrelated limitations remain.

What happens during the operation?

SDR is performed under general anaesthesia by a specialist neurosurgical team. The exact surgical approach differs. Through an opening in the lower back, the surgeon exposes the relevant nerve roots. Sensory roots are separated into rootlets, and electrical stimulation with monitoring helps the team identify response patterns. A selected proportion of rootlets is divided while motor pathways and other structures are protected. The covering of the spinal canal and the surgical wound are then closed.

The operation may use a limited bony opening or a longer exposure depending on the technique and centre. Families should ask the surgeon which approach is planned and why. Time in theatre, postoperative monitoring, pain management and length of hospital stay also vary.

Immediately after surgery, leg tone may be noticeably lower. This does not mean movement is instantly easier. Spasticity may previously have helped compensate for weakness, so the legs can initially feel floppy or difficult to control. The nervous system and muscles need time and practice to work with the new level of tone.

Recovery and rehabilitation after SDR

Rehabilitation begins according to the surgical team’s protocol, often during the hospital admission. Early care may include comfortable positioning, respiratory care, gradual sitting, transfers and reintroduction of movement. Pain, fatigue, temporary sensory changes and fear of movement can affect participation. The pace should be individual rather than based on comparison with another child.

Once medically safe, therapy focuses on rebuilding strength, selective control, balance, endurance and efficient movement. A programme may include bed mobility, sitting, kneeling, standing, transfers, gait training, stairs, play and self-care. Orthoses or walking aids may need review because the child’s alignment and motor strategy have changed.

The intensity and duration of rehabilitation differ between programmes, but families should expect a substantial commitment extending well beyond discharge. Frequent therapy may be required early, followed by progressive home and community practice. School participation, transport, caregiver time and funding need planning before surgery. The operation and the rehabilitation pathway should be considered one treatment, not separate decisions.

Progress is rarely linear. A child may initially lose speed or independence while strength and control are rebuilt. Growth, illness, fatigue and changes in routine can affect performance. Regular reassessment allows the team to adjust exercises, equipment and goals. Our overview of rehabilitation for spasticity explains why activity and participation measures matter alongside muscle tone.

What benefits are possible?

For an appropriately selected person, SDR can produce a durable reduction in lower-limb spasticity. Studies and specialist programmes report improvements in joint movement, gait measures, gross motor function, comfort or ease of care in some patients. The size and meaning of change vary, and improvements reflect both the operation and the rehabilitation that follows.

A successful outcome does not always mean independent walking. For one child, success may be less effort with a walker; for another, easier assisted standing, improved sleep or more comfortable hygiene. Outcomes should therefore be compared with the individual goals agreed before surgery.

SDR does not stop cerebral palsy from affecting motor control, nor does it prevent every musculoskeletal change associated with growth. Weakness may become more visible once spasticity is reduced. Contractures, torsional bone changes, hip displacement or foot deformity may still need orthopaedic monitoring and sometimes treatment. Some children continue to use medicines, orthoses or focal injections for specific problems.

Claims that SDR guarantees normal walking or eliminates all future treatment should be treated cautiously. Ask the centre to explain expected outcomes for patients with a similar functional profile, not only its overall success rate.

Risks, uncertainties and long-term follow-up

SDR is major spinal surgery. Short-term risks include pain, nausea, infection, bleeding, cerebrospinal fluid leak, wound problems, urinary difficulties and complications related to anaesthesia. Temporary changes in sensation or bladder function may occur. Rare but serious neurological complications are possible. The specialist surgeon should explain the centre’s own complication data and how problems are managed.

Longer-term concerns can include persistent weakness, sensory symptoms, changes in bladder function, spinal alignment problems, hip or foot problems and disappointment if functional gains do not match expectations. The risk profile depends on the person, surgical technique, proportion of rootlets divided and length of follow-up. Because children continue to grow, surveillance should not end when the initial rehabilitation programme finishes.

Families should know who will monitor hips, spine, gait, orthoses and function over time. A plan is also needed for pain, increasing difficulty or loss of skills. New problems should not automatically be blamed on “normal recovery.”

How SDR fits among other treatment options

SDR is one option within a broader plan. Physiotherapy and occupational therapy, orthoses, oral medicines, botulinum toxin injections, intrathecal baclofen and orthopaedic procedures address different patterns and goals. Some treatments are reversible or adjustable; SDR is not. A multidisciplinary team should explain why SDR is being considered now and why another option may or may not meet the same goals.

The most appropriate choice is not necessarily the most intensive intervention. If spasticity is not causing pain, limiting function or interfering with care, reducing it may not be the priority. In some people, a degree of tone assists standing or transfers. Treatment decisions should balance potential benefit, burden, reversibility and the person’s preferences.

Questions to ask the SDR team

• Which features make this person a suitable or unsuitable candidate?
• What are the two or three most realistic goals, and how will each be measured?
• Which difficulties are caused by spasticity, and which are due to weakness, dystonia, contracture or bone alignment?
• What surgical technique is used, and what are the centre’s complication rates?
• What will rehabilitation involve during the first weeks, first six months and following year?
• How much therapy, home practice, equipment and caregiver time should be planned?
• Could walking or transfers become temporarily harder after the operation?
• Which treatments or orthopaedic procedures may still be needed later?
• Who provides long-term follow-up for hips, spine, gait and function?
• What happens if the agreed goals are not achieved?

Frequently asked questions

Is SDR a cure for cerebral palsy?

No. It can permanently reduce selected spinal reflex activity and therefore reduce lower-limb spasticity, but it does not reverse the original brain injury or remove every movement difficulty.

Does SDR always improve walking?

No. Some selected patients improve aspects of gait or efficiency, while others have goals related to comfort, care or positioning. Walking also depends on strength, balance, selective control, skeletal alignment and rehabilitation.

Can spasticity return after SDR?

The divided rootlets are permanently cut, but the person may still experience stiffness, spasms or movement limitations from other causes. Growth, contracture, weakness, pain and dystonia can alter function over time.

Will orthopaedic surgery still be needed?

Possibly. SDR reduces neural overactivity but does not directly correct fixed muscle shortening or bone deformity. Hip and musculoskeletal surveillance remain important.

How long does rehabilitation take?

There is no single timetable. Intensive work often begins in hospital and continues for months, with ongoing strengthening, motor learning and follow-up commonly extending beyond the first year. The treating centre should provide a specific pathway before surgery.

Medical disclaimer

This information is provided as a public service and is not a substitute for personal medical advice, diagnosis or treatment. Selective dorsal rhizotomy requires assessment by an experienced multidisciplinary team. Do not make or change a treatment plan on the basis of this page alone.

Last updated: 19 September 2026.