Many children with spinal muscular atrophy (SMA) develop a sideways curve of the spine called scoliosis, and there is a lot we can do about it. Small curves are watched, seating support or a brace can keep your child comfortable, and the newer SMA medicines are changing how the spine behaves. If a curve grows large, surgery can make sitting easier and more comfortable, and this page explains when it is needed and what it involves.
Reviewed by Dr. Kshitij Chaudhary, Last reviewed October 2026
At P.D. Hinduja Hospital, Mahim, Mumbai, our spine team looks after children with SMA, including through a monthly multidisciplinary SMA clinic.
What is scoliosis in SMA?
In SMA, the nerve cells that control the muscles are lost, so the muscles become weak. Scoliosis is a sideways curve of the spine. The spine can also twist, so the ribs or back stick out more on one side.
Weak muscles around the spine cannot hold it upright, so it slowly bends to one side. In SMA this usually makes a long C-shaped curve through the chest and lower back. [1,2] Nothing you or your child did caused the curve.
How common is it?
Scoliosis is one of the most common problems in SMA, and affects up to 9 in 10 children. [1] How likely it is depends on the SMA type.
SMA type | Scoliosis |
Type 1 (starts in the first months of life) | Used to be uncommon, because children did not live long enough to develop a curve. It is now more common, because treated children live longer [1] |
Type 2 (children who sit but do not walk) | The highest risk. Most children develop a curve [1] |
Type 3 (children who walk, some lose walking later) | A lower risk. The curve usually appears later, and is more likely if walking is lost at a young age [1,2] |
Has the new SMA treatment changed things?
Yes. Three medicines have changed SMA care: nusinersen (Spinraza), onasemnogene abeparvovec (Zolgensma) and risdiplam (Evrysdi). Children are now stronger and live longer. [1,2] The effect on the spine depends on when treatment starts:
- Before symptoms: the lowest risk of a significant curve. If SMA is found early, ask the neurologist about starting without delay [1,2]
- After symptoms, in type 2 and type 3: curves tend to be milder and appear later [2]
- Type 1: children now live long enough to develop scoliosis, and curves can start early [1,2]
Scoliosis can still appear in children who are doing well on treatment. So spine checks stay important even when your child's strength is improving.
How will we know if my child has a curve?
A curve often does not hurt at first. The first change is usually how your child sits. Look for:
- One shoulder or hip that looks higher, or uneven ribs or back
- Leaning to one side, or needing more support to stay upright
- A seat that no longer fits, or red marks over a hip or the spine from pressure
Mention these at your next visit. A curve found early is easier to manage.
We confirm it with an X-ray of the whole spine and measure the angle of the curve in degrees. This is the Cobb angle. Curves can grow fastest during growth spurts, so your doctor decides how often to repeat the X-ray, based on your child's age, SMA type and curve. [1,3]
Curve size | What we usually do |
Under about 20 degrees | Watch, with regular checks |
About 20 to 50 degrees | Watch closely. Seating support or a brace may be advised for sitting comfort |
Over about 50 degrees | Talk about surgery, especially in a growing child, or sooner if sitting or breathing is getting worse |
What can we do without surgery?
These measures keep your child comfortable, but none of them stops a growing curve.
- Seating and wheelchair support: seat and trunk supports shaped to your child's curve
- A brace: a firm moulded brace gives trunk support and can help sitting. It does not straighten the curve, and it can make breathing harder. We weigh this carefully for each child [2,3]
- Physiotherapy: keeps the trunk muscles as strong as possible and helps comfort and positioning
- SMA medicines and chest care: carry on with your child's neurologist and breathing team
Ask your physiotherapist before encouraging long periods of upright sitting, especially in young children with type 1 SMA. The trunk muscles need building up first. [1]
When is surgery needed?
Surgery is usually discussed when the curve passes about 50 degrees in a growing child, or sooner if sitting balance, comfort or breathing is getting worse. [1,3] Waiting for problems to appear may not be safe, because curves get harder and riskier to treat as they grow.
Surgery can make sitting easier and more comfortable, and it controls the curve. Its effect on breathing is mixed. It may slow the decline in lung function, but it may not improve it. [2,4] It does not treat SMA itself or bring back muscle strength.
If you're unsure about the advice you've been given, you're welcome to send your scans and reports for a second opinion.
What does surgery involve?
There are two main approaches. We choose between them using your child's age, how much growing is left, the size of the curve and lung function. [1,3]
Growth-friendly rods | Spinal fusion | |
Best for | Younger children with a lot of growing left | Older children and teenagers who have nearly finished growing |
How it works | Rods hold the curve while the spine keeps growing, and are lengthened as your child grows | Rods and screws correct the curve. Bone graft joins the bones into one solid piece |
Trade-off | The spine and chest keep growing, but the rods need a small lengthening operation every so often, with more rod and anchor problems | One main operation with a lasting correction, but it is bigger, and the fused part of the spine stops growing |
These are long operations, done under general anaesthesia by a paediatric anaesthetist, with monitoring of the spinal cord. SMA weakens the breathing muscles, so we check your child's breathing, nutrition and heart before surgery.
How will my child keep getting their SMA medicine?
Nusinersen is injected into the fluid around the spinal cord, through the lower back. After a spinal fusion, new bone can close the gaps the needle passes through. Risdiplam (taken by mouth) and onasemnogene (a single drip) do not need this access.
If your child is on nusinersen, we plan the injection route before surgery, together with your child's neurologist. During the fusion, we leave a small window in the bone, so the injections can carry on. [2,5]
What are the risks of surgery?
Any major spine operation has risks, and some are higher in SMA because the breathing muscles are weak. These include bleeding (sometimes needing a blood transfusion), wound infection, chest infection or breathing problems, and rods or screws that loosen or break and need another operation. Rarely, the spinal cord or nerves are injured.
Growth-friendly rods mean more repeat procedures. Spinal fusion is a bigger single operation, with more bleeding and chest risk. [1,4] Children with type 1 SMA usually have weaker breathing muscles, so their risks may be higher. [1]
We go through your child's own risks in clinic. Our Neuromuscular Scoliosis page lists figures from published studies.
What is recovery like?
- Straight after surgery: your child goes to the paediatric intensive care unit for at least one night. The stay can be longer when the muscles are very weak. Some children need a breathing tube and a ventilator until they are strong enough to manage without it
- In hospital: the stay is usually about a week, sometimes longer. We manage pain, start physiotherapy and teach you how to care for your child at home
- At home: for the first few weeks, your child needs more help with transfers and bathing. By about six weeks, most children move more and need less pain medicine
These timelines are a guide. Children with weaker muscles may take longer. We agree the timing of the next SMA medicine dose with your child's neurologist.
When should we call?
Please contact us if the curve or your child's sitting looks worse, if there is new or growing pain, or if the skin over a hip or the spine is red or broken. If your child has trouble breathing, go to the nearest emergency department.
Questions to ask your doctor
- How big is the curve, and how fast is it growing?
- Do we need seating changes or a brace?
- If surgery is advised: which operation, what are my child's own risks, and how will the SMA medicine carry on?
Treatments we offer for this
Observation and regular follow-up, advice on seating and wheelchair changes, bracing, physiotherapy, and scoliosis correction surgery (growth-friendly rods and posterior spinal fusion with instrumentation).
References
- Gnazzo M, Pisanò G, Piccolo B, Turco EC, Esposito S, Pera MC. Scoliosis in spinal muscular atrophy in the era of disease-modifying therapy: a scoping review. Neurol Sci. 2025;46:3431-3442. doi:10.1007/s10072-025-08155-1
- Ruythooren F, Moens P. Spinal muscular atrophy scoliosis in the era of background therapies: a review of the literature. J Clin Med. 2024;13(12):3467. doi:10.3390/jcm13123467
- Mercuri E, Finkel RS, Muntoni F, et al. Diagnosis and management of spinal muscular atrophy: part 1: recommendations for diagnosis, rehabilitation, orthopedic and nutritional care. Neuromuscul Disord. 2018;28(2):103-115. doi:10.1016/j.nmd.2017.11.005
- Swarup I, MacAlpine EM, Mayer OH, et al. Impact of growth friendly interventions on spine and pulmonary outcomes of patients with spinal muscular atrophy. Eur Spine J. 2021;30(3):768-774. doi:10.1007/s00586-020-06564-8
- Labianca L, Weinstein SL. Scoliosis and spinal muscular atrophy in the new world of medical therapy: providing lumbar access for intrathecal treatment in patients previously treated or undergoing spinal instrumentation and fusion. J Pediatr Orthop B. 2019;28(4):393-396. doi:10.1097/BPB.0000000000000632
This page is for general information and does not replace a medical consultation. Please see a doctor for advice about your own symptoms.
About Dr. Kshitij Chaudhary
This page was written by Dr. Kshitij Chaudhary, a fellowship-trained spine surgeon at P.D. Hinduja Hospital, Mumbai, trained in complex spine surgery at Harvard Medical School (Beth Israel Deaconess) and the Twin Cities Spine Center, Minneapolis. About Dr. Chaudhary
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